Abstract:
This invention provides novel arylindenopyridines of the formula: 
                         
 
and pharmaceutical compositions comprising same, useful for treating disorders ameliorated by antagonizing Adensine A2a receptors or reducing PDE activity in appropriate cells. This invention also provides therapeutic and prophylactic methods using the instant pharmaceutical compositions.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of co-pending application Ser. No. 10/123,389, filed on Apr. 16, 2002, which claims the benefit of Provisional application Ser. No. 60/284,465 filed Apr. 18, 2001, which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to novel arylindenopyridines and their therapeutic and prophylactic uses. Disorders treated and/or prevented using these compounds include neurodegenerative and movement disorders ameliorated by antagonizing Adenosine A2a receptors and inflammatory and AIDS-related disorders ameliorated by inhibiting phosphodiesterace activity. 
     BACKGROUND OF THE INVENTION 
     Adenosine A2a Receptors 
     Adenosine is a purine nucleotide produced by all metabolically active cells within the body. Adenosine exerts its effects via four subtypes of cell-surface receptors (A1, A2a, A2b and A3), which belong to the G protein coupled receptor superfamily (Stiles, G. L. Journal of Biological Chemistry, 1992, 267, 6451). A1 and A3 couple to inhibitory G protein, while A2a and A2b couple to stimulatory G protein. A2a receptors are mainly found in the brain, both in neurons and glial cells (highest level in the striatum and nucleus accumbens, moderate to high level in olfactory tubercle, hypothalamus, and hippocampus etc. regions) (Rosin, D. L.; Robeva, A.; Woodard, R. L.; Guyenet, P. G.; Linden, J. Journal of Comparative Neurology , 1998, 401, 163). 
     In peripheral tissues, A2a receptors are found in platelets, neutrophils, vascular smooth muscle and endothelium (Gessi, S.; Varani, K.; Merighi, S.; Ongini, E.; Borea, P. A. British Journal of Pharmacology, 2000, 129, 2). The striatum is the main brain region for the regulation of motor activity, particularly through its innervation from dopaminergic neurons originating in the substantia nigra. The striatum is the major target of the dopaminergic neuron degeneration in patients with Parkinson&#39;s Disease (PD). Within the striatum, A2a receptors are co-localized with dopamine D2 receptors, suggesting an important site of for the integration of adenosine and dopamine signaling in the brain (Fink, J. S.; Weaver, D. R.; Rivkees, S. A.; Peterfreund, R. A.; Pollack, A. E.; Adler, E. M.; Reppert, S. M. Brain Research Molecular Brain Research, 1992, 14, 186). 
     Neurochemical studies have-shown that activation of A2a receptors reduces the binding affinity of D2 agonist to their receptors. This D2R and A2aR receptor-receptor interaction has been demonstrated in striatal membrane preparations of rats (Ferre, S.; von Euler, G.; Johansson, B.; Fredholm, B. B.; Fuxe, K. Proceedings of the National Academy of Sciences of the United States of America, 1991, 88, 7238) as well as in fibroblast cell lines after transfected with A2aR and D2R cDNAs (Salim, H.; Ferre, S.; Dalal, A.; Peterfreund, R. A.; Fuxe, K.; Vincent, J. D.; Lledo, P. M. Journal of Neurochemistry, 2000, 74, 432). In vivo, pharmacological blockade of A2a receptors using A2a antagonist leads to beneficial effects in dopaminergic neurotoxin MPTP(1-methyl-4-pheny-l,2,3,6-tetrahydropyridine)-induced PD in various species, including mice, rats, and monkeys (Ikeda, K.; Kurokawa, M.; Aoyama, S.; Kuwana, Y. Journal of Neurochemistry, 2002, 80, 262). Furthermore, A2a knockout mice with genetic blockade of A2a function have been found to be less sensitive to motor impairment and neurochemical changes when they were exposed to neurotoxin MPTP (Chen, J. F.; Xu, K,; Petzer, J. P.; Staal, R.; Xu, Y. H.; Beilstein, M.; Sonsalla, P. K.; Castagnoli, K.; Castagnoli, N., Jr.; Schwarzschild, M. A. Journal of Neuroscience, 2001, 21, RC143). 
     In humans, the adenosine receptor antagonist theophylline has been found to produce beneficial effects in PD patients (Mally, J.; Stone, T. W. Journal of the Neurological Sciences, 1995, 132, 129). Consistently, recent epidemiological study has shown that high caffeine consumption makes people less likely to develop PD (Ascherio, A.; Zhang, S. M.; Hernan, M. A.; Kawachi, I.; Colditz, G. A.; Sp izer, F. E.; Willett, W. C. Annals of Neurology, 2001, 50, 56). In summary, adenosine A2a receptor blockers may provide a new class of antiparkinsonian agents (Impagnatiello, F.; Bastia, E.; Ongini, E.; Monopoli, A. Emerging Therapeutic Targets, 2000, 4, 635). 
     Phosphodiesterase Inhibitors 
     There are eleven known families of phosphodiesterases (PDE) widely distributed in many cell types and tissues. In their nomenclature, the number indicating the family is followed by a capital letter that indicates a distinct gene. A PDE inhibitor increases the concentration of CAMP in tissue cells, and hence, is useful in the prophylaxis or treatment of various diseases caused by the decrease in cAMP level which is induced by the abnormal metabolism of CAMP. These diseases include conditions such as hypersensitivity, allergy, arthritis, asthma, bee sting, animal bite, bronchospasm, dysmenorrhea, esophageal spasm, glaucoma, premature labor, a urinary tract disorder, inflammatory bowel disease, stroke, erectile dysfunction, HIV/AIDS, cardiovascular disease, gastrointestinal motility disorder, and psoriasis. 
     Among known phosphodiesterases today, PDE1 family are activated by calcium-calmodulin; its members include PDE1A and PDE1B, which preferentially hydrolyze cGMP, and PDE1C which exhibits a high affinity for both CAMP and cGMP. PDE2 family is characterized as being specifically stimulated by cGMP. PDE2A is specifically inhibited by erythro-9(2-hydroxy-3-nonyl)adenine (EHNA). Enzymes in the PDE3 family (e.g. PDE3A, PDE3B) are specifically inhibited by cGMP. PDE4 (e.g. PDE4A, PDE4B, PDE4C, PDE4D) is a cAMP specific PDE present in T-cells, which is involved in inflammatory responses. A PDE3 and/or PDE4 inhibitor would be predicted to have utility in the following disorders: autoimmune disorders (e.g. arthritis), inflammatory bowel disease, bronchial disorders (e.g. asthma), HIV/AIDS, and psoriasis. A PDE5 (e.g. PDE5A) inhibitor would be useful for the treatment of the following disorders: cardiovascular disease and erectile dysfunction. The photoreceptor PDE6 (e.g. PDE6A, PDE6B, PDE6C) enzymes specifically hydrolyze cGMP. PDE8 family exhibits high affinity for hydrolysis of both cAMP and cGMP but relatively low sensitivity to enzyme inhibitors specific for other PDE families. 
     Phosphodiesterase 7 (PDE7A, PDE7B) is a cyclic nucleotide phosphodiesterase that is specific for cyclic adenosine monophosphate (cAMP). PDE7 catalyzes the conversion of cAMP to adenosine monophosphate (AMP) by hydrolyzing the 3′-phosphodiester bond of cAMP. By regulating this conversion, PDE7 allows for non-uniform intracellular distribution of cAMP and thus controls the activation of distinct kinase signalling pathways. PDE7A is primarily expressed in T-cells, and it has been shown that induction of PDE7A is required for T-cell activation (Li, L.; Yee, C.; Beavo, J. A.  Science  1999, 283, 848). Since PDE7A activation is necessary for T-cell activation, small molecule inhibitors of PDE7 would be useful as immunosuppressants. An inhibitor of PDE7A would be predicted to have immunosuppressive effects with utility in therapeutic areas such as organ transplantation, autoimmune disorders (e.g. arthritis), HIV/AIDS, inflammatory bowel disease, asthma, allergies and psoriasis. 
     Few potent inhibitors of PDE7 have been reported. Most inhibitors of other phosphodiesterases have IC 50 &#39;s for PDE7 in the 100 μM range. Recently, Martinez, et a/. ( J. Med. Chem.  2000, 43, 683) reported a series of PDE7 inhibitors, among which the two best compounds have PDE7 IC 50 &#39;s of 8 and 13 μM. However, these compounds were only 2-3 times selective for PDE7 over PDE4 and PDE3. 
     Finally the following compounds have been disclosed, and some of them are reported to show antimicrobial activity against strains such as  Plasmodium falciparum, Candida albicans  and  Staphylococcus aureus  (Gorlitzer, K.; Herbig, S.; Walter, R. D.  Pharmazie  1997, 504): 
                        
 
     SUMMARY OF THE INVENTION 
     This invention provides a compound having the structure of Formula I 
                        
 
or a pharmaceutically acceptable salt thereof, wherein
     (a) R 1  is selected from the group consisting of:
       (i) —COR 5 , wherein R 5  is selected from H, optionally substituted C 1-8  straight or branched chain alkyl, optionally substituted aryl and optionally substituted arylalkyl;    wherein the substituents on the alkyl, aryl and arylalkyl group are selected from C 1-8  alkoxy, phenylacetyloxy, hydroxy, halogen, p-tosyloxy, mesyloxy, amino, cyano, carboalkoxy, or NR 20 R 21  wherein R 20  and R 21  are independently selected from the group consisting of hydrogen, C 1-8  straight or branched chain alkyl, C 3-7  cycloalkyl, benzyl, aryl, or heteroaryl or NR 20 R 21  taken together form a heterocycle or heteroaryl;   (ii) COOR 6 , wherein R 6  is selected from H, optionally substituted C 1-8  straight or branched chain alkyl, optionally substituted aryl and optionally substituted arylalkyl;    wherein the substituents on the alkyl, aryl and arylalkyl group are selected from C 1-8  alkoxy, phenylacetyloxy, hydroxy, halogen, p-tosyloxy, mesyloxy, amino, cyano, carboalkoxy, or NR 20 R 21  wherein R 20  and R 21  are independently selected from the group consisting of hydrogen, C 1-8  straight or branched chain alkyl, C 3-7  cycloalkyl, benzyl, aryl, or heteroaryl or NR 20 R 21  taken together form a heterocycle or heteroaryl;   (iii) cyano;   (iv) a lactone or lactam formed with R 4;      (v) —CONR 7 R 8  wherein R 7  and R 8  are independently selected from H, C 1-8  straight or branched chain alkyl, C 3-7  cycloalkyl, trifluoromethyl, hydroxy, alkoxy, acyl, alkylcarbonyl, carboxyl, arylalkyl, aryl, heteroaryl and heterocyclyl;
           wherein the alkyl, cycloalkyl, alkoxy, acyl, alkylcarbonyl, carboxyl, arylalkyl, aryl, heteroaryl and heterocyclyl groups may be substituted with carboxyl, alkyl, aryl, substituted aryl, heterocyclyl, substituted heterocyclyl, heteroaryl, substituted heteroaryl, hydroxamic acid, sulfonamide, sulfonyl, hydroxy, thiol, alkoxy or arylalkyl,   
            or R 7  and R 8  taken together with the nitrogen to which they are attached form a heterocycle or heteroaryl group;   (vi) a carboxylic ester or carboxylic acid bioisostere including optionally substituted heteroaryl groups   
       (b) R 2  is selected from the group consisting of optionally substituted alkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted heterocyclyl and optionally substituted C 3-7  cycloalkyl;   (c) R 3  is from one to four groups independently selected from the group consisting of:
       (i) hydrogen, halo, C 1-8  straight or branched chain alkyl, arylalkyl, C 3-7  cycloalkyl, C 1-8  alkoxy, cyano, C 1-4  carboalkoxy, trifluoromethyl, C 1-8  alkylsulfonyl, halogen, nitro, hydroxy, trifluoromethoxy, C 1-8  carboxylate, aryl, heteroaryl, and heterocyclyl;   (ii) &#39;NR 12 R 11  wherein R 10  and R 11  are independently selected from H, C 1-8  straight or branched chain alkyl, arylalkyl, C 3-7  cycloalkyl, carboxyalkyl, aryl, heteroaryl, and heterocyclyl or R 10  and R 11  taken together with the nitrogen form a heteroaryl or heterocyclyl group;   (iii) —NR 12 COR 13  wherein R 12  is selected from hydrogen or alkyl and R 13  is selected from hydrogen, alkyl, substituted alkyl, C 1-3 alkoxyl, carboxyalkyl, R 30 R 31 N (CH 2 ) p —, R 30 R 31 NCO(CH 2 ) p —, aryl, arylalkyl, heteroaryl and heterocyclyl or R 12  and R 13  taken together with the carbonyl form a carbonyl containing heterocyclyl group, wherein, R 30  and R 31  are independently selected from H, OH, alkyl, and alkoxy, and p is an integer from 1-6,    wherein the alkyl group may be substituted with carboxyl, alkyl, aryl, substituted aryl, heterocyclyl, substituted heterocyclyl, heteroaryl, substituted heteroaryl, hydroxamic acid, sulfonamide, sulfonyl, hydroxy, thiol, alkoxy or arylalkyl;   
       (d) R 4  is selected from the group consisting of (i) hydrogen, (ii) C 1-3  straight or branched chain alkyl, (iii) benzyl and (iv) —NR 13 R 14 , wherein R 13  and R 14  are independently selected from hydrogen and C 1-6  alkyl;    wherein the C 1-3  alkyl and benzyl groups are optionally substituted with one or more groups selected from C 3-7  cycloalkyl, C 1-8  alkoxy, cyano, C 1-4  carboalkoxy, trifluoromethyl, C 1-8  alkylsulfonyl, halogen, nitro, hydroxy, trifluoromethoxy, C 1-8  carboxylate, amino, NR 13 R 14 , aryl and heteroaryl; and   (e) X is selected from S and O;
 
with the proviso that when R 4  is isopropyl, then R 3  is not halogen.
   

     In an alternative embodiment, the invention is directed to compounds of Formula I wherein R 1 , R 3  and R 4  are as described above and R 2  is —NR 15 R 16  wherein R 15  and R 16  are independently selected from hydrogen, optionally substituted C 1-8  straight or branched chain alkyl, arylalkyl, C 3-7  cycloalkyl, aryl, heteroaryl, and heterocyclyl or R 15  and R 16  taken together with the nitrogen form a heteroaryl or heterocyclyl group; with the proviso that when R 2  is NHR 16 R 1  is not —COOR 6  where R 6  is ethyl. 
     This invention also provides a pharmaceutical composition comprising the instant compound and a pharmaceutically acceptable carrier. 
     This invention further provides a method of treating a subject having a condition ameliorated by antagonizing Adenosine A2a receptors or by reducing PDE activity in appropriate cells, which comprises administering to the subject a therapeutically effective dose of the instant pharmaceutical composition. 
     This invention further provides a method of preventing a disorder ameliorated by antagonizing Adenosine A2a receptors or by reducing PDE activity in appropriate cells in a subject, comprising administering to the subject a prophylactically effective dose of the compound of claim  1  either preceding or subsequent to an event anticipated to cause a disorder ameliorated by antagonizing Adenosine A2a receptors or reducing PDE activity in appropriate cells in the subject. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Compounds of Formula 1 are potent small molecule antagonists of the Adenosine A2a receptors that have demonstrated potency for the antagonism of Adenosine A2a, A1, and A3 receptors. 
     Compounds of Formula I are also potent small molecule phosphodiesterase inhibitors that have demonstrated potency for inhibition of PDE7, PD E5, and PDE4. Some of the compounds of this invention are potent small molecule PDE7 inhibitors which have also demonstrated good selectivity against PDE5 and PDE4. 
     Preferred embodiments for R 1  are COOR 6 , wherein R 6  is selected from H, optionally substituted C 1-8  straight or branched chain alkyl, optionally substituted aryl and optionally substituted arylalkyl. Preferably R 6  is H, or C 1-8  straight or branched chain alkyl which may be optionally substituted with a substituent selected from CN and hydroxy. 
     Preferred embodiments for R 2  are optionally substituted heterocycle, optionally substituted aryl and optionally substituted heteroaryl. Preferred substituents are from one to three members selected from the group consisting of halogen, alkyl, alkoxy, alkoxyphenyl, halo, triflouromethyl; trifluoro or difluoromethoxy, amino, alkylamino, hydroxy, cyano, and nitro. Preferably, R 2  is optionally substituted furan, phenyl or napthyl or R 2  is 
                        
 
optionally substituted with from one to three members selected from the group consisting of halogen, alkyl, hydroxy, cyano, and nitro. In another embodiment of the instant compound, R 2  is —NR 15 R 16 .
 
     Preferred substituents for R 3  include:
         (i) hydrogen, halo, C 1-8  straight or branched chain alkyl, C 1-8  alkoxy, cyano, C 1-4  carboalkoxy, trifluoromethyl, C 1-8  alkylsulfonyl, halogen, nitro, and hydroxy;   (ii) —NR 10 R, 11  wherein R 10  and R 11  are independently selected from H, C 1-8  straight or branched chain alkyl, arylC 1-8 alkyl, C 3-7  cycloalkyl, carboxyC 1-8 alkyl, aryl, heteroaryl, and heterocyclyl or R 10  and R 11 , taken together with the nitrogen form a heteroaryl or heterocyclyl group;   (iii) —NR 12 COR 13  wherein R 12  is selected from hydrogen or alkyl and R 13  is selected from hydrogen, alkyl, substituted alkyl, C 1-3 alkoxyl, carboxyC 1-8 alkyl, aryl, arylalkyl, R 30 R 31 N (CH 2 ) p —, R 30 R 31 NCO(CH 2 ) p —, heteroaryl and heterocyclyl or R 12  and R 13  taken together with the carbonyl form a carbonyl containing heterocyclyl group, wherein , R 30  and R 31  are independently selected from H, OH, alkyl, and alkoxy, and p is an integer from 1∝6.       

     Particularly, R 3  is selected from the group consisting of 
                        
 
alkyl(CO)NH—, NH 2 , and NO 2 .
 
     Preferred embodiments for R 4  include hydrogen, C 1-3  straight or branched chain alkyl, particularly methyl, amine and amino. 
     In a further embodiment of the instant compound, R 1  is COOR 6  and R 2  is selected from the group consisting of substituted phenyl, and substituted naphthyl or R 2  is NR 15 R 16 . 
     More particularly, R 1  is COOR 6  where R 6  is alkyl, R 2  is substituted phenyl or naphthyl or R 2  is NR 15 R 16 , and R 3  is selected from the group consisting of H, nitro, amino, NHAc, halo, hydroxy, alkoxy, or a moiety of the formulae: 
                        
 
alkyl(CO)NH—, and R 4  is selected from hydrogen, C 1-3  straight or branched chain alkyl, particularly methyl, and amino.
 
     In a preferred embodiment, the compound is selected from the group of compounds shown in Table 1 hereinafter. 
     More preferably, the compound is selected from the following compounds: 
                        
 
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 2-amino4(1,3-benzodioxol-5yl)-5-oxo-, ethyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 4-(6-bromo-1,3-benzodioxol-5-yl)-2-methyl-5-oxo-, ethyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 7-amino4-(1,3 -benzodioxol-5-yl)-2-methyl-5-oxo-, ethyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 4-(6-bromo-1,3-benzodioxol-5-yl)-2-methyl-5-oxo-, methyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 4-(3,5-dimethylphenyl)-2-methyl-5-oxo-, methyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 8-(acetylamino)41,3-benzodioxol-5-yl)-2-methyl-5-oxo-, ethyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 2-methyl4-(3-methylphenyl)5-oxo-, methyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 7-amino-4-(3,5-dimethylphenyl)-2-methyl-5-oxo-, methyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 7-amino-2-methyl4-(4-methyl-1-naphthalenyl)-5-oxo-, methyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 4-(3,5dibromo-4-hydroxyphenyl)-2-methyl-8-nitro-5-oxo-, methyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 7,8-dichloro-4-(3,5-dibromo-4-hydroxyphenyl)-2-methyl-5-oxo-, methyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 7-bromo(3,5-dibromo-4 -hydroxyphenyl)-2-methyl-5-oxo-, methyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 8-bromo-4-(3,5-dibromo-4 -hydroxyphenyl)2-methyl-5-oxo-, methyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 8-[(3-carboxy-1-oxopropyl)amino]-4-(3,5-dimethylphenyl-2-methyl-5-oxo-, methyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 8-[(3-carboxy-1-oxopropyl)amino]-2-methyl-4-(4-methyl-1-naphthalenyl)-5oxo-, methyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 4-(3,5-dimethylphenyl)-8-[[4-(hydroxyamino)-1,4-dioxobutyl]amino]-2-methyl-5-oxo-, methyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 4-(3,5dimethylphenyl)-8[[[(2-hydroxyethyl)amino]acetyl]amino]-2-methyl-5-oxo, methyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 8-[(4-carboxy-1-oxobutyl)amino]-4-(3,5-dimethylphenyl)-2-methyl-5-oxo-, methyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 4-(3,5-dimethylphenyl)-8-[[[(2-hydroxyethyl)methylamino]acetyl]amino]-2-methyl-5-oxo-, methyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 4-(3,5dimethylphenyl)-2-methyl-8-[(4-morpholinylacetyl)amino]-5-oxo-, methyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 4-(3,5-dimethylphenyl)-2-methyl-5-oxo-8-[(1-piperazinylacetyl)amino]-, methyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 4-phenyl-2-amino-oxo-, ethyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 4-(4-methylphenyl)-2-methyl-5-oxo-, methyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 4-(3-bromophenyl)2-methyl-5-oxo-, methyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 4-(3-bromophenylamino)-2-methyl-5-oxo-, methyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 4-phenyl-2-amino-5-oxo-, methyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 4-(2-furyl)-2-amino-5-oxo-, methyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 4-(3-furyl)-2-amino-5-oxo-, methyl ester 
     
       
                 
         
             
             
         
      
     
     5H-indeno[1,2-b]pyridine-3-carboxylic acid, 4-(2-furyl)-2-amino-5-oxo-, ethyl ester 
     The instant compounds can be isolated and used as free bases. They can also be isolated and used as pharmaceutically acceptable salts. Examples of such salts include hydrobromic, hydroiodic, hydrochloric, perchloric, sulfuric, maleic, fumaric, malic, tartaric, citric, benzoic, mandelic, methanesulfonic, hydroethanesulfonic, benzenesulfonic, oxalic, palmoic, 2-naphthalenesulfonic, p-toluenesulfonic, cyclohexanesulfamic and saccharic. 
     This invention also provides a pharmaceutical composition comprising the instant compound and a pharmaceutically acceptable carrier. 
     Pharmaceutically acceptable carriers are well known to those skilled In the art and include, but are not limited to, from about 0.01 to about 0.1 M and preferably 0.05 M phosphate buffer or 0.8% saline. Such pharmaceutically acceptable carriers can be aqueous or non-aqueous solutions, suspensions and emulsions. Examples of non-aqueous solvents are propylene glycol, polyethylene glycol, vegetable oils such as olive oil, and injectable organic esters such as ethyl oleate. Aqueous carriers include water, ethanol, alcoholic/aqueous solutions, glycerol, emulsions or suspensions, including saline and buffered media. Oral carriers can be elixirs, syrups, capsules, tablets and the like. The typical solid carrier is an inert substance such as lactose, starch, glucose, methyl-cellulose, magnesium stearate, dicalcium phosphate, mannitol and the like. Parenteral carriers include sodium chloride solution, Ringer&#39;s dextrose, dextrose and sodium chloride, lactated Ringer&#39;s and fixed oils. Intravenous carriers include fluid and nutrient replenishers, electrolyte replenishers such as those based on Ringer&#39;s dextrose and the like. Preservatives and other additives can also be present, such as, for example, antimicrobials, antioxidants, chelating agents, inert gases and the like. All carriers can be mixed as needed with disintegrants, diluents, granulating agents, lubricants, binders and the like using conventional techniques known in the art. 
     This invention further provides a method of treating a subject having a condition ameliorated by antagonizing Adenosine A2a receptors or by reducing PDE activity in appropriate cells, which comprises administering to the subject a therapeutically effective dose of the instant pharmaceutical composition. 
     In one embodiment, the disorder is a neurodegenerative or movement disorder. In another embodiment, the disorder is an inflammatory disorder. In still another embodiment, the disorder is an AIDS-related disorder. Examples of disorders treatable by the instant pharmaceutical composition include, without limitation, Parkinson&#39;s Disease, Huntington&#39;s Disease, Multiple System Atrophy, Corticobasal Degeneration, Alzheimer&#39;s Disease, Senile Dementia, organ transplantation, autoimmune disorders (e.g. arthritis), immune challenge such as a bee sting, inflammatory bowel disease, bronchial disorders (e.g. asthma), HIV/AIDS, cardiovascular disorder, erectile dysfunction, allergies, and psoriasis. 
     In one preferred embodiment, the disorder is rheumatoid arthritis. 
     In another preferred embodiment, the disorder is Parkinson&#39;s disease. 
     As used herein, the term “subject” includes, without limitation, any animal or artificially modified animal having a disorder ameliorated by reducing PDE activity in appropriate cells. In a preferred embodiment, the subject is a human. In a more preferred embodiment, the subject is a human, 
     As used herein, “appropriate cells” include, by way of example, cells which display PDE activity. Specific examples of appropriate cells include, without limitation, T-lymphocytes, muscle cells, neuro cells, adipose tissue cells, monocytes, macrophages, fibroblasts. 
     Administering the instant pharmaceutical composition can be effected or performed using any of the various methods known to those skilled in the art. The instant compounds can be administered, for example, intravenously, intramuscularly, orally and subcutaneously. In the preferred embodiment, the instant pharmaceutical composition is administered orally. Additionally, administration can comprise giving the subject a plurality of dosages over a suitable period of time. Such administration regimens can be determined according to routine methods. 
     As used herein, a “therapeutically effective dose” of a pharmaceutical composition is an amount sufficient to stop, reverse or reduce the progression of a disorder. A “prophylactically effective dose” of a pharmaceutical composition is an amount sufficient to prevent a disorder, i.e., eliminate, ameliorate and/or delay the disorder&#39;s onset. Methods are known in the art for determining therapeutically and prophylactically effective doses for the instant pharmaceutical composition. The effective dose for administering the pharmaceutical composition to a human, for example, can be determined mathematically from the results of animal studies. 
     In one embodiment, the therapeutically and/or prophylactically effective dose is a dose sufficient to deliver from about 0.001 mg/kg of body weight to about 200 mg/kg of body weight of the instant pharmaceutical composition. In another embodiment, the therapeutically and/or prophylactically effective dose is a dose sufficient to deliver from about 0.05 mg/kg of body weight to about 50 mg/kg of body weight. More specifically, in one embodiment, oral doses range from about 0.05 mg/kg to about 100 mg/kg daily. In another embodiment, oral doses range from about 0.05 mg/kg to about 50 mg/kg daily, and in a further embodiment, from about 0.05 mg/kg to about 20 mg/kg daily. In yet another embodiment, infusion doses range from about 1.0 μg/kg/min to about 10 mg/kg/min of inhibitor, admixed with a pharmaceutical carrier over a period ranging from about several minutes to about several days. In a further embodiment, for topical administration, the instant compound can be combined with a pharmaceutical carrier at a drug/carrier ratio of from about 0.001 to about 0.1. 
     This invention still further provides a method of preventing an inflammatory response in a subject, comprising administering to the subject a prophylactically effective amount of the instant pharmaceutical composition either preceding or subsequent to an event anticipated to cause the inflammatory response in the subject. In the preferred embodiment, the event is an insect sting or an animal bite. 
     Definitions and Nomenclature 
     Unless otherwise noted, under standard nomenclature used throughout this disclosure the terminal portion of the designated side chain is described first, followed by the adjacent functionality toward the point of attachment. 
     As used herein, the following chemical terms shall have the meanings as set forth in the following paragraphs: “independently”, when in reference to chemical substituents, shall mean that when more than one substituent exists, the substituents may be the same or different;. 
     “Alkyl” shall mean straight, cyclic and branched-chain alkyl. Unless otherwise stated, the alkyl group will contain 1-20 carbon atoms. Unless otherwise stated, the alkyl group may be optionally substituted with one or more groups such as halogen, OH, CN, mercapto, nitro, amino, C 1 -C 8 -alkyl, C 1 -C 8 -alkoxyl, C 1 -C 8 -alkylthio, C 1 -C 8 -alkyl-amino, di(C 1 -C 8 -alkyl)amino, (mono-, di-, tri-, and per-) halo-alkyl, formyl, carboxy, alkoxycarbonyl, C 1 -C 8 -alkyl-CO—O—, C 1 -C 8 -alkyl-CO—NH—, carboxamide, hydroxamic acid, sulfonamide, sulfonyl, thiol, aryl, aryl(c 1 -c 8 )alkyl, heterocyclyl, and heteroaryl. 
     “Alkoxy” shall mean —O-alkyl and unless otherwise stated, it will have 1-8 carbon atoms. 
     The term “bioisostere ” is defined as “groups or molecules which have chemical and physical properties producing broadly similar biological properties.” (Burger&#39;s Medicinal Chemistry and Drug Discovery, M. E. Wolff, ed. Fifth Edition, Vol. 1, 1995, Pg. 785). 
     “Halogen” shall mean fluorine, chlorine, bromine or iodine; “PH” or “Ph” shall mean phenyl; “Ac” shall mean acyl; “Bn” shall mean benzyl. 
     The term “acyl” as used herein, whether used alone or as part of a substituent group, means an organic radical having 2 to 6 carbon atoms (branched or straight chain) derived from an organic acid by removal of the hydroxyl group. The term “Ac” as used herein, whether used alone or as part of a substituent group, means acetyl. 
     “Aryl” or “Ar,” whether used alone or as part of a substituent group, is a carbocyclic aromatic radical Including, but not limited to, phenyl, 1- or 2-naphthyl and the like. The carbocyclic aromatic radical may be substituted by independent replacement of 1 to 5 of the hydrogen atoms thereon with halogen, OH, CN, mercapto, nitro, amino, C 1 -C 8 -alkyl, C 1 -C 8 -alkoxyl, C 1 -C 8 -alkylthio, C 1 -C 8 -alkyl-amino, di(C 1 -C 8 -alkyl)amino, (mono-, di-, tri-, and per-) halo-alkyl, formyl, carboxy, alkoxycarbonyl, C 1 -C 8 -alkyl-CO—O—, C 1 -C 8 -alkyl-CO—NH—, or carboxamide. Illustrative aryl radicals include, for example, phenyl, naphthyl, biphenyl, fluorophenyl, difluorophenyl, benzyl, benzoyloxyphenyl, carboethoxyphenyl, acetylphenyl, ethoxyphenyl, phenoxyphenyl, hydroxyphenyl, carboxyphenyl, trifluoromethylphenyl, methoxyethylphenyl, acetamidophenyl, tolyl, xylyl, dimethylcarbamylphenyl and the like. “Ph” or “PH” denotes phenyl. 
     Whether used alone or as part of a substituent group, “heteroaryl” refers to a cyclic, fully unsaturated radical having from five to ten ring atoms of which one ring atom is selected from S, O, and N; 0-2 ring atoms are additional heteroatoms independently selected from S, O, and N; and the remaining ring atoms are carbon. The radical may be joined to the rest of the molecule via any of the ring atoms. Exemplary heteroaryl groups include, for example, pyridinyl, pyrazinyl, pyrimidinyl, pyridazinyl, pyrroyl, pyrazolyl, imidazolyl , thiazolyl, oxazolyl, isoxazolyl, thiadiazolyl, triazolyl, triazinyl, oxadiazolyl, thienyl, furanyl, quinolinyl, isoquinolinyl, indolyl, isothiazolyl, 2-oxazepinyl, azepinyl, N-oxo-pyridyl, 1-dioxothienyl, benzothiazolyl, benzoxazolyl, benzothienyl, quinolinyl-N-oxide, benzimidazolyl, benzopyranyl, benzisothiazolyl, benzisoxazolyl, benzodiazinyl, benzofurazanyl, benzothiopyranyl, indazolyl, indolizinyl, benzofuryl, chromonyl, coumarinyl, cinnolinyl, quinoxalinyl, indazolyl, pyrrolopyridinyl, furopyridinyl (such as furo[2,3-c]pyridinyl, furo[3,2-b]pyridinyl, or furo[2,3-b]pyridinyl), imidazopyridinyl (such as imidazo[4,5-b]pyridinyl or imidazo[4,5-c]pyridinyl), naphthyridinyl, phthalazinyl, purinyl, pyridopyridyl, quinazolinyl, thienofuryl, thienopyridyl, thienothienyl, and furyl. The heteroaryl group may be substituted by independent replacement of 1 to 5 of the hydrogen atoms thereon with halogen, OH, CN, mercapto, nitro, amino, C 1 -C 8 -alkyl, C 1 -C 8 -alkoxyl, C 1 -C 8 -alkylthio, C 1 -C 8 -alkyl-amino, di(C 1 -C 8 -alkyl)amino, (mono-, di-, tri-, and per-) halo-alkyl, formyl, carboxy, alkoxycarbonyl, C 1 -C 8 -alkyl-CO—O—, C 1 -C 8 -alkyl-CO—NH—, or carboxamide. Heteroaryl may be substituted with a mono-oxo to give for example a 4-oxo-1H-quinoline. 
     The terms “heterocycle,” “heterocyclic,” and “heterocycle” refer to an optionally substituted, fully or partially saturated cyclic group which is, for example, a 4- to 7-membered monocyclic, 7- to 11-membered bicyclic, or 10- to 15-membered tricyclic ring system, which has at least one heteroatom in at least one carbon atom containing ring. Each ring of the heterocyclic group containing a heteroatom may have 1, 2, or 3 heteroatoms selected from nitrogen atoms, oxygen atoms, and sulfur atoms, where the nitrogen and sulfur heteroatoms may also optionally be oxidized. The nitrogen atoms may optionally be quaternized. The heterocyclic group may be attached at any heteroatom or carbon atom. 
     Exemplary monocyclic heterocyclic groups include pyrrolidinyl; oxetanyl; pyrazolinyl; imidazolinyl; imidazolidinyl; oxazolyl; oxazolidinyl; isoxazolinyl; thiazolidinyl; isothiazolidinyl; tetrahydrofuryl; piperidinyl; piperazinyl; 2-oxopiperazinyl; 2-oxopiperidinyl; 2-oxopyrrolidinyl; 4-piperidonyl; tetrahydropyranyl; tetrahydrothiopyranyl; tetrahydrothiopyranyl sulfone; morpholinyl; thiomorpholinyl; thiomorpholinyl sulfoxide; thiomorpholinyl sulfone; 1,3-dioxolane; dioxanyl; thietanyl; thiiranyl; and the like. Exemplary bicyclic heterocyclic groups include quinuclidinyl; tetrahydroisoquinolinyl; dihydroisoindolyl; dihydroquinazolinyl (such as 3,4-dihydro-4-oxo-quinazolinyl); dihydrobenzofuryl; dihydrobenzothienyl; dihydrobenzothiopyranyl; dihydrobenzothiopyranyl sulfone; dihydrobenzopyranyl; indolinyl; isochromanyl; isoindolinyl; piperonyl; tetrahydroquinolinyl; and the like. 
     Substituted aryl, substituted heteroaryl, and substituted heterocycle may also be substituted with a second substituted-aryl, a second substituted-heteroaryl, or a second substituted-heterocycle to give, for example, a 4-pyrazol-1-yl-phenyl or 4-pyridin-2-yl-phenyl. 
     Designated numbers of carbon atoms (e.g., C 1-8 ) shall refer independently to the number of carbon atoms in an alkyl or cycloalkyl moiety or to the alkyl portion of a larger substituent in which alkyl appears as its prefix root. 
     Unless specified otherwise, it is intended that the definition of any substituent or variable at a particular location in a molecule be independent of its definitions elsewhere in that molecule. It is understood that substituents and substitution patterns on the compounds of this invention can be selected by one of ordinary skill in the art to provide compounds that are chemically stable and that can be readily synthesized by techniques known in the art as well as those methods set forth herein. 
     Where the compounds according to this invention have at least one stereogenic center, they may accordingly exist as enantiomers. Where the compounds possess two or more stereogenic centers, they may additionally exist as diastereomers. Furthermore, some of the crystalline forms for the compounds may exist as polymorphs and as such are intended to be included in the present invention. In addition, some of the compounds may form solvates with water (i.e., hydrates) or common organic solvents, and such solvates are also intended to be encompassed within the scope of this invention. 
     Some of the compounds of the present invention may have trans and cis isomers. In addition, where the processes for the preparation of the compounds according to the invention give rise to mixture of stereoisomers, these isomers may be separated by conventional techniques such as preparative chromatography. The compounds may be prepared as a single stereoisomer or in racemic form as a mixture of some possible stereoisomers. The non-racemic forms may be obtained by either synthesis or resolution. The compounds may, for example, be resolved into their components enantiomers by standard techniques, such as the formation of diastereomeric pairs by salt formation. The compounds may also be resolved by covalent linkage to a chiral auxiliary, followed by chromatographic separation and/or crystallographic separation, and removal of the chiral auxiliary. Alternatively, the compounds may be resolved using chiral chromatography. 
     This invention will be better understood by reference to the Experimental Details which follow, but those skilled in the art will readily appreciate that these are only illustrative of the invention as described more fully in the claims which follow thereafter. Additionally, throughout this application, various publications are cited. The disclosure of these publications is hereby incorporated by reference into this application to describe more fully the state of the art to which this invention pertains. 
     Experimental Details 
     I. General Synthetic Schemes 
     Representative compounds of the present invention can be synthesized in accordance with the general synthetic methods described below and illustrated in the following general schemes. The products of some schemes can be used as intermediates to produce more than one of the instant compounds. The choice of intermediates to be used to produce subsequent compounds of the present invention is a matter of discretion that is well within the capabilities of those skilled in the art. 
                        
 
     Procedures described in Scheme 1, wherein R 3a , R 3b , R 3c , and R 3d  are independently any R 3  group, and R 1 , R 2 , R 3 , and R 4  are as described above, can be used to prepare compounds of the invention wherein X is O. 
     Benzylidenes 2 may be obtained by known methods (Bullington, J. L; Cameron, J. C.; Davis, J. E.; Dodd, J. H.; Harris, C. A.; Henry, J. R.; Pellegrino-Gensey, J. L.; Rupert, K. C.; Siekierka, J. J. Bioorg. Med. Chem. Lett. 1998, 8, 2489; Petrow, V.; Saper, J.; Sturgeon, B. J. Chem. Soc. 1949, 2134). Hantzsch reaction of the benzylidene compounds with enamines 3 can be performed in refluxing acetic acid (Petrow et al., supra). When the desired enamines are not available, alternate Hantzsch conditions may be utilized which involve adding ammonium acetate to the reaction. The resulting dihydropyridines 4 are oxidized with chromium trioxide to obtain the desired pyridines 1 (Petrow et al., supra). In cases where the substitution pattern on the fused aromatic ring (R 3 ) leads to a mixture of regioisomers, the products can be separated by column chromatography. 
     In some cases, especially where R 2  is an alkyl group, another modification of the Hantzsch may be performed which uses three components (Bocker, R. H.; Buengerich, P.  J. Med. Chem.  1986, 29, 1596). Where R 2  is an alkyl group it is also necessary to perform the oxidation with DDQ or MnO 2  instead of chromium (VI) oxide (Vanden Eynde, J. J.; Delfosse, F.; Mayence, A.; Van Haverbeke, Y.  Tetrahedron  1995, 51, 6511). 
                        
 
     In order to obtain the corresponding carboxylic acids and amides, the cyanoethyl esters 5 are prepared as described above. The esters are converted to the carboxylic acids by treatment with sodium hydroxide in acetone and water (Ogawa, T.; Matsumoto, K.; Yokoo, C.; Hatayama, K.; Kitamura, K.  J. Chem. Soc., Perkin Trans.  1 1993, 525). The corresponding amides can then be obtained from the acids using standard means. 
                        
 
     The procedure for making compounds where R 4  is NH 2  may be slightly modified. These compounds are prepared in one step from the benzylidenes 2 and alkyl amidinoacetate (Kobayashi, T.; Inoue, T.; Kita, Z.; Yoshiya, H.; Nishino, S.; Oizumi, K.; Kimura, T. Chem. Pharm. Bull. 1995, 43, 788) as depicted in Scheme 4 wherein R is R 5  or R 6  as described above. 
                        
 
     The dihydropyridine lactones 9 can be synthesized from benzylidenes 8 (Zimmer, H.; Hillstrom, W. W.; Schmidt, J. C.; Seemuth, P. D.; Vogeli, R.  J. Org. Chem.  1978, 43, 1541) and 1,3-indanedione, as shown in Scheme 5, and the corresponding pyridine is then obtained by oxidation with manganese dioxide. 
                        
 
     Representative schemes to modify substituents on the fused aromatic ring are shown below. The amines 11 are obtained from the corresponding nitro compounds 10 by reduction with tin (II) chloride (Scheme 6). Reaction of the amines with acetyl chloride provide the amides 12. 
                        
 
     In accordance with Scheme 7 wherein Y is 0, and n is an integer from 1-3, an alkyl chain with a carboxylic acid at the terminal end can also be added to the amines 11. For example, reaction with either succinic anhydrid (Omuaru, V. O. T.;  Indian J. Chem.,  Sect B. 1998, 37, 814) or β-propiolactone (Bradley, G.; Clark, J.; Kernick, W.  J. Chem. Soc., Perkin Trans.  1 1972, 2019) can provide the corresponding carboxylic acids 13. These carboxylic acids are then converted to the hydroxamic acids 14 by treatment with ethyl chloroformate and hydroxylamin (Reddy, A. S.; Kumar, M. S.; Reddy, G. R.  Tetrahedron Lett.  2000, 41, 6285). 
                        
 
     The amines 11 can also be treated with glycolic acid to afford alcohols 15 (Jursic, B. S.; Zdravkovski, Z.  Synthetic Comm.  1993,23, 2761) as shown in Scheme 8. 
                        
 
     As shown in Scheme 9, the aminoindenopyridines 11 may also be treated with chloroacetylchloride followed by amines to provide the more elaborate amines 16 (Weissman, S. A.; Lewis, S.; Askin, D.; Volante, R. P.; Reider, P. J.  Tetrahedron Led.  1998, 39,7459). Where R 6  is a hydroxyethyl group, the compounds can be further converted to piperazinones 17. 
                        
 
     The 4-aminoindenopyridines 19 can be synthesized from the 4-chloroindenopyridines 18 using a known procedure (Gorlitzer, K.; Herbig, S.; Walter, R. D.  Pharmazie  1997, 504) or via palladium catalyzed coupling (Scheme 10). 
                        
 
     Cyanoesters 20 can be prepared by known methods (Lee, J.; Gauthier, D.; Rivero, R. A.  J. Org. Chem.  1999, 64, 3060). Reaction of 20 with enaminone 21 (lida, H.; Yuasa, Y.; Kibayashi, C. J. Org. Chem. 1979, 44, 1074) in refluxing 1-propanol and triethylamine gave dihydropyridine 22, wherein R is R 5  or R 6  as described above, (Youssif, S.; El-Bahaie, S.; Nabih, E.  J. Chem. Res.  (S) 1999, 112 and Bhuyan, P.; Borush, R. C.; Sandhu, J. S.  J. Org. Chem.  1990, 55, 568), which can then be oxidized and subsequently deprotected to give pyridine 23. 
                        
 
II. Specific Compound Syntheses
 
     Specific compounds which are representative of this invention can be prepared as per the following examples. No attempt has been made to optimize the yields obtained in these reactions. Based on the following, however, one skilled in the art would know how to increase yields through routine variations in reaction times, temperatures, solvents and/or reagents. 
     The products of certain syntheses can be used as intermediates to produce more than one of the instant compounds. In those cases, the choice of intermediates to be used to produce compounds of the present invention is a matter of discretion that is well within the capabilities of those skilled in the art. 
     EXAMPLE 1 
     Hantzsch Condensation to Form Dihydropyridine 4 (R 1 =COOMe; R 2 =3,5-dimethylphenyl; R 3b,c =Cl; R 3a,b =H; R 4 =Me) 
     To a refluxing solution of benzylidene 2 (0.500 g, 1.5 mmol) in acetic acid (10 mL) was added methyl-3-aminocrotonate (0.695 g, 6.0 mmol). The reaction was heated to reflux for 20 minutes, then water was added until a precipitate started to form. The reaction was cooled to room temperature. The mixture was filtered and washed with water to obtain 0.354 g (55%) of a red solid. MS m/z 450 (M + +23), 428 (M + +1). 
     EXAMPLE 2 
     Alternate Hantzsch Conditions to Form Dihydropyridine 4 (R 1 =CO 2 Me; R 2 =2,4-dimethylphenyl; R 3 =H; R 4 =Et) 
     To a refluxing solution of benzylidene 2 (1.00 g, 3.82 mmol) in acetic acid (12 Ml) was added methyl propionylacetate (1.98 g, 15.2 mmol) and ammonium acetate (1.17 g, 15.2 mmol). The reaction was heated for 20 min and then cooled to room temperature. No product precipitated from the solution, so the reaction was heated to reflux and then water was added until a solid began to precipitate. After cooling to room temperature, the mixture was filtered and the red solid washed with water to yield 1.29 g (90%) of product. MS m/z 396 (M + +23), 374 (M + +1). 
     EXAMPLE 3 
     Oxidation of Dihydropyridine 4 to Pyridine 1 (R 1 =COOMe; R 2 =3,5-dimethylphenyl; R 3a,b =Cl; R 3a,d =H; R 4 =Me) 
     To a refluxing solution of dihydropyridine 4 (0.250 g, 0.58 mmol) in acetic acid (10 mL) was added a solution of chromium (VI) oxide (0.584 g, 0.58 mmol) in 1 mL water. After 30 minutes at reflux, the reaction was diluted with water until a precipitate started to form. The mixture was cooled to room temperature and allowed to stand overnight. The mixture was filtered and washed with water to give 0.199 g (81%) of a yellow solid. MS m/z 448 (M + +23), 426 (M + +1). 
     EXAMPLE 4 
     Oxidation of Dihydropyridine 4 to Pyridine 1 (R 1 =COOMe; R 2 =(4-methyl)-1-naphthyl; R 3b,c =H, NO 2 /NO 2 , H; R=Me) 
     To a refluxing suspension of regioisomeric dihydropyridines 4 (3.59 g, 8.16 mmol) in acetic acid (40 mL) was added a solution of chromium (VI) oxide (0.816 g, 8.16 mmol) in 3 mL water. After 20 minutes at reflux, the reaction was diluted with water until a precipitate started to form. The mixture was cooled to room temperature and allowed to stand overnight. The mixture was filtered and washed with water to yield the mixture of regioisomers as a yellow solid. The products were purified by column chromatography eluting with hexanes:ethyl acetate to yield 1.303 g (37%) of pyridine 1 (R 3b =NO 2 ; R 3c =H) and 0.765 g (21%) of its regioisomer (R 3b =H; R 3c =N0 2 ). MS m/z 461 (M + +23), 439 (M + +1). 
     EXAMPLE 5 
     Alternate Three Component Hantzsch Reaction to Form Dihydropyridine 4 (R 1 =CO 2 Me; R 2 =cyclohexyl; R 3 =H; R 4 =Me) 
     Cyclohexane carboxaldehyde (2.0 g, 17.8 mmol), 1,3-indandione (2.6 g, 17.8 mmol), methylacetoacetate (2.0 g, 17.8 mmol), and ammonium hydroxide (1 mL) were refluxed in 8 mL of methanol for 1.5 hours. The temperature was lowered to approximately 50° C. and the reaction was stirred overnight. The reaction was cooled to room temperature, filtered and the solid washed with water. The residue was then dissolved in hot ethanol and filtered while hot. The filtrate was concentrated to yield 4.1 g (68%) of the product which was used without purification. MS m/z 336 (M − −1). 
     EXAMPLE 6 
     DDQ Oxidation of Dihydropyridine 4 (R 1 =CO 2 Me; R 2 =cyclohexyl: R 3 =H; R 4 =Me) 
     To a solution of dihydropyridine 4 (2.50 g, 7.40 mmol) in 15 mL of dichloromethane was added 2,3-dichloro-3,6-dicyano-1,4-benzoquinone (1.70 g, 7.40 mmol). The reaction was stirred at room temperature for four hours. The mixture was filtered and the residue was washed with dichloromethane. After the filtrate was concentrated, the residue was purified by column chromatography eluting with ethyl acetate: hexanes to yield 0.565 g (23%) of a yellow solid. MS m/z 358 (M + +23), 336 (M + +1). 
     EXAMPLE 7 
     MnO 2  Oxidation of Dihydropyridine 4 (R 1 =CO 2 Me; R 2 =4-(dimethylamino)phenyl: R 3 =H; R 4 =Me) 
     To a solution of dihydropyridine 4 (0.50 g, 1.3 mmol) in 10 mL of dichloromethane was added manganese dioxide (2.5 g, 28.7 mmol). The reaction was stirred at room temperature overnight before filtering and washing with dichloromethane. The filtrate was concentrated to yield 0.43 g (88%) of orange solid 1. MS m/z 395 (M + +23), 373 (M + +1). 
     EXAMPLE 8 
     Cleavage of Carboxylic Ester 5 (R 2 =2,4-dimethylphenyl; R 3 =H; R 4 =Me) 
     To a suspension of ester 5 (2.75 g, 6.94 mmol) in acetone (50 mL) was added aqueous 1 M NaOH (100 mL). After stirring at room temperature for 24 hours, the reaction mixture was diluted with 100 mL of water and washed with dichloromethane (2×100 mL). The aqueous layer was cooled to 0° C. and acidified with concentrated HCl. The mixture was filtered and washed with water to yield 1.84 g (77%) yellow solid 6. MS m/z 366 (M + +23), 343 (M + +1). 
     EXAMPLE 9 
     Preparation of Amide 7 (R 2 =2.4-dimethylphenyl; R 3 =H; R 4 =Me; R 5 =H; R 6 =Me) 
     A solution of carboxylic acid 6 (0.337 g, 0.98 mmol) in thionyl chloride (10 mL) was heated at reflux for 1 hour. The solution was cooled and concentrated in vacuo. The residue was diluted with CCl 4  and concentrated to remove the residual thionyl chloride. The residue was then dissolved in THF (3.5 mL) and added to a 0° C. solution of methylamine (1.47 mL of 2.0 M solution in THF, 2.94 mmol) in 6.5 mL THF. The reaction was warmed to room temperature and stirred overnight. The mixture was poured into water, filtered, washed with water and dried to yield 0.263 g (75%) of tan solid. MS m/z 357(M + +1). 
     EXAMPLE 10 
     Preparation of Pyridine 1 (R 1 =CO 2 Et: R 2 =4-nitrophenyl; R 3 =H; R 4 =NH 2 ) 
     To a refluxing solution of benzylidene 2 (1.05 g, 3.76 mmol) in 10 mL of acetic acid was added ethyl amidinoacetate acetic acid salt (0.720 g. 3.76 mmol). The resulting solution was heated at reflux overnight. After cooling to room temperature, the resulting precipitate was removed by filtration and washed with water. This impure residue was heated in a minimal amount of ethanol and then filtered to yield 0.527 g (35%) of a yellow solid. MS m/z 412 (M + +23), 390 (M + +1). 
     EXAMPLE 11 
     Hantzsch Condensation of Benzylidene 8 (R 2 =3-methoxyphenyl) and 1,3-indandione) 
     The benzylidene 8 (2.00 g, 9.2 mmol), 1,3-indandione (1.34 g, 0.2 mmmol) and ammonium acetate (2.83 g, 36.7 mmol) were added to 30 mL of ethanol and heated to reflux overnight. The reaction mixture was cooled to room temperature and diluted with ethanol. A yellow precipitate was collected by filtration, washed with ethanol, and dried under vacuum to yield 1.98 g (63%) of the dihydropyridine 9. MS m/z 346 (M + +1). 
     EXAMPLE 12 
     Reduction to Prepare Amine 11 (R 1 =CO 2 Me; R 2 =4-methylnaphthyl; R 4 =Me) 
     To a refluxing suspension of pyridine 10 (0.862 g, 1.97 mmol) in 35 mL of ethanol was added a solution of tin (II) chloride dihydrate (1.33 g, 5.90 mmol) in 6 mL of 1:1 ethanol: concentrated HCl. The resulting solution was heated at reflux overnight. Water was added until a precipitate started to form and the reaction was cooled to room temperature. The mixture was then filtered and washed with water. After drying, the residue was purified by column chromatography eluting with hexanes: ethyl acetate to yield 0.551 g (69%) of an orange solid. MS m/z 431 (Me + +23), 409 (M + +1). 
     EXAMPLE 13 
     Acetylation of Amine 11 (R 1 =CO 2 Et; R 2 =3,4-methylenedioxyphenyl; R 4 =Me) 
     To a solution of amine 11 (0.070 g, 0.174 mmol) in 15 mL of dichloromethane was added triethylamine (0.026 g, 0.261 mmol) and acetyl chloride (0.015 g, 0.192 mmol). After stirring overnight at room temperature, the reaction mixture was diluted with water and then extracted with dichloromethane (3×35 mL). The combined organics were washed with brine, dried over MgSO 4 , and concentrated. The residue was purified by silica gel chromatography eluting with hexanes: ethyl acetate to yield 0.054 g (70%) of amide 12. MS m/z 467 (M + +23), 445 (M + +1). 
     EXAMPLE 14 
     Preparation of Carboxylic Acid 13 (R 1 =CO 2 Me; R 2 =3,5dimethylphenyl; R 4 =Me; Y=O; n=2) 
     To a suspension of amine 11 (0.079 g, 0.212 mmol) in 5 mL of benzene was added succinic anhydride (0.021 g, 0.212 mmol). After heating at reflux for 24 hours, the reaction mixture was filtered and washed with benzene. The residue was dried under high vacuum and then washed with ether to remove the excess succinic anhydride. This yielded 0.063 g (63%) of carboxylic acid 13. MS m/z 473 (M + +1). 
     EXAMPLE 15 
     Preparation of Carboxylic Acid 13 (R 1 =CO 2 Me; R 2 =3,5-dimethylphenyl: R 4 =Me; Y=H 2 : n=1) 
     To a refluxing solution of amine 11 (0.078 g, 0.210 mmol) in 5 mL of acetonitrile was added β-propiolactone (0.015 g, 0.210 mmol). The reaction was heated to reflux for 72 hours before cooling to room temperature. The reaction mixture was concentrated. The residue was mixed with 10% aqueous sodium hydroxide and washed sequentially with ether and ethyl acetate. The aqueous layer was acidified with concentrated HCl and extracted with dichloromethane (2×25 mL). The combined organics were dried over MgSO 4 , filtered, and concentrated. The residue was purified by column chromatography eluting with 5% MeOH in dichloromethane to yield 0.020 g (21%) of an orange solid. MS m/z 467 (M + +23), 445 (M + +1). 
     EXAMPLE 16 
     Preparation of Hydroxamic Acid 14 (R 1 =CO 2 Me; R 2 =(4-methyl)-1-naphthyl: Y=O; n=2; R 4 =Me) 
     To a 0° C. suspension of carboxylic acid 13 (0.054 g, 0.106 mmmol) in 10 mL of diethyl ether was added triethylamine (0.014 g, 0.138 mmol) and then ethyl chloroformate (0.014 g, 0.127 mmol). The mixture was stirred at 0° C. for 30 minutes and them warmed to room temperature. A solution of hydroxylamine (0.159 mmol) in methanol was added and the reaction was stirred overnight at room temperature. The mixture was filtered and the residue was washed with ether and dried under vacuum to yield 0.030 g (54%) of a yellow solid. MS m/z 524 (M + +1). 
     EXAMPLE 17 
     Preparation of Amide 15 (R 1 =CO 2 Me; R 2 =3,5-dimethylphenyl: R 4 =Me) 
     A mixture of amine 11 (0.201 g, 0.54 mmol) and glycolic acid (0.049 g, 0.65 mmol) was heated at 120-160° C. for 30 minutes. During heating, more glycolic acid was added to ensure that excess reagent was present. Once the starting material was consumed, the reaction was cooled to room temperature, and diluted with dichloromethane. The resulting mixture was extracted with 20% NaOH, followed by 10% HCl, and finally water. The combined organics were concentrated and triturated with ether. Purification by column chromatography eluting with ethyl acetate: hexanes yielded 0.012 g, (5%) of a yellow solid. MS m/z453 (M + +23), 431 (M + +1). 
     EXAMPLE 18 
     Preparation of Amide 16 (R 1 =CO 2 Me; R 2 =3,5-dimethylphenyl; R 4 =Me; NR 6 R 7 =morpholino) 
     To a 0° C. mixture of amine 11 (0.123 g, 0.331 mmol) in 2 mL of 20% a aqueous NaHCO 3  and 3 mL of ethyl acetate was added chloroacetyl chloride (0.047 g, 0.413 mmol). The reaction was warmed to room temperature and stirred for 45 minutes. The mixture was poured into a separatory funnel and the aqueous layer was removed. The organic layer containing the crude chloroamide was used without purification. To the ethyl acetate solution was added morpholine (0.086 g, 0.992 mmol) and the reaction was heated to approx. 65° C. overnight. The reaction was diluted with water and cooled to room temperature. After extraction with ethyl acetate (3×25 mL), the combined organics were washed with brine, dried over MgSO 4  and concentrated to yield 0.130 g (79%) of a yellow solid. MS m/z 522 (M + +23), 500 (M + +1). 
     EXAMPLE 19 
     Preparation of piperazinone 17 (R 1 =CO 2 Me; R 2 =3,5-dimethylphenyl; R 4 =Me; R 7 =H) 
     To a 0° C. solution of amide 16 (R 6 =CH 2 CH 2 OH) (0.093 g, 0.20 mmol), tri n-butylphosphine (0.055 g, 0.27 mmol) in 0.35 mL ethyl acetate was slowly added di-tert-butyl azodicarboxylate (0.062 g, 0.27 mmol) in 0.20 mL ethyl acetate. The reaction was allowed to stand for 15 minutes and then heated to 40° C. overnight. 4.2 M ethanolic HCl was added dropwise. The mixture was cooled to 0° C. and allowed to stand for 2 hours. The mixture was filtered and washed with cold ethyl acetate. Purification by column chromatography with 1-5% MeOH in CH 2 Cl 2  yielded 0.011 (12%) of a white solid. MS m/z 478 (M + +23), 456 (M + +1). 
     EXAMPLE 20 
     Preparation of 4-Aminoindenopyridine 19 (R 1 =CO 2 Me; R 4 =Me; R 6 =Me; R 7 =phenyl) 
     To a solution of 4-chloroindenopyridine 18 (0.069 g, 0.240 mmol) in 10 mL of 2-ethoxyethanol was added N-methylaniline (0.026 g, 0.240 mmol). The reaction was heated at reflux for 96 hours. After cooling to room temperature, the solution was concentrated. The residue was purified by column chromatography eluting with hexanes: ethyl acetate to yield 0.029 g (34%) of an orange solid. MS m/z 359 (M + +1). 
     EXAMPLE 21 
     Preparation of 4-Aminoindenopyridine 19 (R 1 =CO 2 Me; R 4 =Me; R 6 =H; R 7 =cyclopentyl) by Palladium Catalyzed Coupling 
     A mixture of 4-chloroindenopyridine 18 (0.100 g, 0.347 mmol), cyclopentylamine (0.035 g, 0.416 mmol), palladium (II) acetate (0.004 g, 0.0017 mmol), 2-(di-t-butylphosphino)biphenyl (0.010 g, 0.0035 mmol), and cesium carbonate (0.124 g, 0.382 mmol) in 10 mL of dioxane was heated at reflux overnight. The reaction was cooled to room temperature, diluted with water, and extracted with ethyl acetate (3×35 mL). The combined organics were washed with brine, dried over Na 2 SO 4 , and concentrated. The residue was purified by column chromatography eluting with ethyl acetate: hexanes. The purified oil was dissolved in ether and cooled to 0° C. To this solution was slowly added 1.0 M HCl in ether. The resulting precipitate was isolated by filtration, washed with ether, and dried under vacuum to yield 0.032 g (25%) of a yellow solid. MS m/z 359 (M + +23), 337 (M + +1). 
     EXAMPLE 22 
     Preparation of Dihydropyridine 21 (R 1 =CO 2 Me; R 2 =2-furyl; R 3 =H; R 4 =NH 2 ) 
     Unsaturated cyanoester 20 (0.20g, 1.10 mmol), enamine 21 (0.20g, 0.75 mmol) and 5 drops of triethylamine were refluxed in 1-propanol (4 mL). After 3 hours, the reaction was concentrated to half the volume and cooled. The resulting precipitate was filtered and washed with 1-propanol. The precipitate was a mixture of products and therefore was combined with the filtrate and concentrated. Purification by column chromatography, eluting with ethyl acetate: hexane yielded 0.11 g (34%) of the red product 22. MS m/z465 (M + +23). 
     EXAMPLE 23 
     DDQ Oxidation/Deprotection of Dihydropyridine 22 (R 1 =CO 2 Me; R 2 =3-furyl; R 3 =H; R 4 =NH 2 ) 
     To a solution of dihydropyridine 22(0.05 g, 0.11 mmol) in chlorobenzene (4 mL) was added 2,3-dichloro-3,6-dicyano-1,4-benzoquinone (0.05g, 0.22 mmol). The reaction was refluxed overnight before cooling to room temperature and diluting with diethyl ether. The reaction mixture was filtered through celite and concentrated in vacuo. Purification by column chromatography, eluting with ethyl acetate:hexane yielded 0.018 g (52%) of yellow product 23. MS m/z 343 (M + +23), 321 (M + +1). 
     Following the general synthetic procedures outlined above and in Examples 1-21, the compounds of Table 1 below were prepared. 
                                                                                                       TABLE 1                   Ia                                                                                   MS       No.   R 1     R 2     R 3a     R 3b     R 3c     R 3d     R 4     (M + 1)                    1   CN                                 H   H   H   H   Me   341       2   CO 2 Et                                 H   H   H   H   Me   388       3   CO 2 t-Bu                                 H   H   H   H   Me   416       4   CO 2 t-Bu                                 H   H   H   H   Me   432       5   CO 2 Et                                 H   H   H   H   Me   389       6   CO 2 H                                 H   H   H   H   Me   360       7   CO 2 Et                                 H   H   H   H   Me   480       8   CO 2 Et                                 H   H   H   H   Me   482       9   CO 2 Et                                 H   H   H   H   Me   424       10   CO 2 H                                 H   H   H   H   Me   376       11   CO 2 Et   Ph   H   H   H   H   Me   344       12   CO 2 Et                                 H   H   H   H   Me   374       13   CO 2 Et                                 H   H   H   H   Me   434       14   CO 2 Et                                 H   H   H   H   Me   454       15   CO 2 Bn                                 H   H   H   H   Me   450       16                                                               H   H   H   H   Me   507       17   CO 2 Me                                 H   H   H   H   Me   390       18   CO 2 Me                                 H   H   H   H   Me   374       19   CO 2 Et                                 H   H   H   H   Me   404       20   CO 2 Et                                 H   H   H   H   Me   404       21   CO 2 Et                                 H   H   H   H   Me   454       22   CO 2 Et                                 H   H   H   H   NH 2     411 (M + 23)       23   CO 2 Et                                 H   H   H   H   Me   388       25   CO 2 Et                                 H   H   H   H   NH 2     405       26   CO 2 Et                                 H   H   H   H   NH 2     390       27   CO 2 Et   Ph   H   H   H   H   NH 2     345       28   CO 2 Et                                 H   H   H   H   Me   402       29   CO 2 Et                                 H   H   H   H   Me   483       30   CO 2 Me   Ph   H   H   H   H   Me   330       31   CO 2 Et                                 H   H   H   H   Me   402       32   CO 2 Et                                 H   NO 2     H   H   Me   433       33                                                               H   H   H   H   Me   413       34   CO 2 Et                                 H   H   H   H   Me   433       35   CO 2 Et                                 H   H   NO 2     H   Me   433       36   CO 2 Me                                 H   H   H   H   Me   398       37   CO 2 Et                                 H   H   NH 2     H   Me   403       38   CONH 2                                   H   H   H   H   Me   359       39   CO 2 Et                                 H   H   H   H   Me   372       40   CO 2 Et                                 H   NH 2     H   H   Me   403       41   CO 2 Et                                 H   H   H   H   Me   334       42   CO 2 Et   2-Thienyl   H   H   H   H   Me   350       43   CO 2 Me                                 H   H   H   H   Me   358       44   CO 2 Me                                 H   H   H   H   Me   388       45   CO 2 Me                                 H   H   H   H   Me   419       46   CO 2 Me                                 H   H   H   H   Me   388       47   CO 2 Me   4-Pyridyl   H   H   H   H   Me   331       48   CO 2 Me                                 H   H   H   H   Me   374       49   CO 2 Me                                 H   H   H   H   Me   454       50   CO 2 Me                                 H   H   H   H   Me   439       51   CO 2 Me                                 H   H   H   H   Me   358       52   CO 2 Et                                 H   H   H   H   Me   372       53   CO 2 Me                                 H   H   H   H   Me   410       54   CO 2 Me                                 H   H   H   H   Me   375       55   CO 2 Et                                 H   NHAc   H   H   Me   445       56   CO 2 Et                                 H   H   NHAc   H   Me   445       57   CO 2 Et                                 H   H   H   H   Me   358       58   CO 2 Et                                 H   H   H   H   Me   358       59   CO 2 Et                                 H   H   H   H   Me   358       60   CO 2 Et                                 H   NO 2     H   H   Me   457       61   CO 2 Et                                 H   H   NO 2     H   Me   457       62   CO 2 Me                                 H   H   H   H   Me   344       63   CO 2 Et                                 H   NH 2     H   H   Me   427       64   CO 2 Et                                 H   H   NH 2     H   Me   427       65   CO 2 Me                                 H   H   H   H   Me   466       66   CO 2 Me                                 H   H   H   H   Me   344       67   CO 2 Me                                 H   H   H   H   Me   344       68   CO 2 Me                                 H   NO 2     H   H   Me   443       69   CO 2 Me                                 H   H   NO 2     H   Me   443       70   CO 2 Et                                 H   H   H   H   i-Pr   400       71   CO 2 Me                                 H   NH 2     H   H   Me   413       72   CO 2 Me                                 H   H   H   H   Me   399       73   CO 2 Me                                 H   H   H   H   Et   372       74   CO 2 Me                                 H   H   H   H   Me   398       75   CO 2 Me                                 H   H   H   H   Me   394       76   CO 2 Me                                 H   H   H   H   Me   372       77   CO 2 Me                                 H   NO 2     H   H   Me   403       78   CO 2 Me                                 H   H   NO 2     H   Me   403       79   CO 2 Me                                 H   H   H   H   Me   394       80   CO 2 Me                                 H   NHAc   H   H   Me   455       81   CO 2 Me                                 H   H   H   H   Me   488       82   CO 2 Me                                 H   NH 2     H   H   Me   373       83   CO 2 Me                                 H   H   NH 2     H   Me   373       84   CO 2 Me                                 H   H   H   H   Me   362       85   CO 2 Me                                 H   H   H   H   Me   431 (M + 23)       86   CO 2 Me                                 H   H   H   H   Me   380 (M + 23)       87   CO 2 Me                                 H   NO 2     H   H   Me   439       88   CO 2 Me                                 H   H   NO 2     H   Me   439       89   CO 2 Me                                 H   H   H   H   Me   430       90   CO 2 Me                                 H   NH 2     H   H   Me   409       91   CO 2 Me                                 H   H   NH 2     H   Me   409       92                                                               H   H   H   H   Me   397       93   CN                                 H   H   H   H   Me   325       94   CO 2 Me                                 H   H   H   H   NH 2     359       95   CO 2 Me                                 H   H   H   H   NH 2     395       96   CO 2 H                                 H   H   H   H   Me   344       97                                                               H   H   H   H   Me   433       98   CN                                 H   H   H   H   Me   361       99                                                               H   H   H   H   C 2 H 2 O 2     358       100                                                               H   H   H   H   C 2 H 2 O 2     357       101                                 Ph   H   H   H   H   C 2 H 2 O 2     314       102                                 p-C 6 H 4 NO 2     H   H   H   H   C 2 H 2 O 2     361       103                                                               H   H   H   H   C 2 H 2 O 2     364       104                                                               H   H   H   H   C 2 H 2 O 2     342       105   CO 2 H                                 H   H   H   H   Me   380       106   CONH 2                                   H   H   H   H   Me   343       107   CONHMe                                 H   H   H   H   Me   357       108   CONMe 2                                   H   H   H   H   Me   371       109                                                               H   H   H   H   C 2 H 2 O 2     378       110                                                               H   H   H   H   C 2 H 2 O 2     328       111                                                               H   H   H   H   C 2 H 2 O 2     356       112                                                               H   H   H   H   C 2 H 2 O 2     328       113   CO 2 Me                                 H   H   H   H   Me   375       114                                                               H   H   H   H   C 2 H 2 O 2     328       115   CO 2 Me                                 H   H   H   H   Me   373       116   CONH 2                                   H   H   H   H   Me   379       117                                                               H   H   H   H   C 2 H 2 O 2     365       118   CO 2 Me                                 H   H   H   H   Me   375       119   CONHMe                                 H   H   H   H   Me   393       120   CONMe 2                                   H   H   H   H   Me   407       121   CO 2 Me                                 H   H   H   H   Me   381       122   CO 2 Me                                 H   Cl   Cl   H   Me   463       123   CO 2 Me                                 H   Cl   Cl   H   Me   427       124   CO 2 Me                                 H   H   H   H   Me   381       125   CO 2 Et                                 H   H   H   H   Me   408       126   CO 2 Me                                 H   Cl   Cl   H   Me   555       127   CO 2 Me                                 Cl   H   H   Cl   Me   427       128   CO 2 Me   2-NO 2 -4,5-   H   H   H   H   Me   421               OCH 2 O—               C 6 H 2         129   CO 2 Me                                 Cl   H   H   Cl   Me   558       130   CO 2 Me                                 H   H   H   H   Me   345       131   CO 2 Et                                 H   Cl   Cl   H   Me   477       132   CO 2 Me                                 H   H   H   H   Me   503       133   Ac                                 H   H   H   H   Me   472       134   Ac                                 H   H   H   H   Me   342       135   CO 2 Me                                 H   H   H   H   Me   331       136                                                               H   H   H   H   Me   527       137                                                               H   H   H   H   Me   397       138   CO 2 Me                                 H   H   H   H   Me   362       139   CO 2 H                                 H   H   H   H   Me   474       140   CO 2 H                                 H   H   H   H   Me   344       141   CO 2 Me                                 H   H   H   H   Me   346       142   CO 2 Me                                 H   H   H   H   Me   380       143   CO 2 Me                                 H   H   H   H   Me   486       144   CO 2 Me                                 H   H   H   H   Me   436       145   CO 2 Me                                 H   H   H   H   Me   518       146                                                               H   H   H   H   Me   557       147                                                               H   Cl   Cl   H   Me   466       148   CO 2 Et   —NHPh   H   H   H   H   Me   359       149   CO 2 Me                                 H   H   H   H   Me   360       150   CO 2 Me                                 H   H   H   H   Me   504       151                                                               H   H   H   H   Me   420       152   C 3 H 5 O 3                                   H   H   H   H   Me   534       153                                                               H   H   H   H   Me   385       154                                                               H   H   H   H   Me   373       155                                                               H   H   NO 2     H   Me   574       156   CO 2 Me                                 H   Br   H   H   Me   473       157   CO 2 Me                                 H   H   Br   H   Me   473       158                                                               H   Cl   Cl   H   Me   489       159                                                               H   H   NO 2     H   Me   590       160                                                               H   H   H   H   Me   411       161   CO 2 Me                                 H   Br   H   H   Me   436       162   CO 2 Me                                 H   H   Br   H   Me   438       163   CO 2 Me                                 H   Br   Br   H   Me   516       164                                                               H   Cl   Cl   H   Me   597       165                                                               H   Cl   Cl   H   Me   480       166   CO 2 Me                                 H   Br   Br   H   Me   552       167   CO 2 Et                                 H   Br   Br   H   Me   530       168   CO 2 Me                                 F   H   H   F   Me   540       169   CO 2 Me                                 H   H   NO 2     H   Me   551       170   CO 2 Me                                 H   Cl   Cl   H   Me   573       171                                                               H   H   NO 2     H   Me   444       172                                                               H   NO 2     H   H   Me   444       173   CO 2 Me                                 F   H   H   F   Me   394       174                                                               F   H   H   F   Me   433       175   CO 2 Me                                 H   Br   Br   H   Me   548       176   CO 2 Me                                 H   H   H   H   Me   355       177   CO 2 Me                                 H   NO 2     H   H   Me   421       178   CO 2 Me                                 H   H   NO 2     H   Me   453 (M + 23)       179   CO 2 Me                                 H   Cl   Cl   H   Me   443       180   CN                                 H   H   H   H   Me   341       181   CO 2 Me                                 H   H   H   H   Me   598       182   CO 2 Me                                 H   Cl   Cl   H   Me   435       183   CO 2 Et                                 H   H   H   H   Me   387       184   CO 2 Et                                 H   H   H   H   Me   373       185   CO 2 Me                                 H   H   H   H   Me   612       186   CO 2 Et                                 H   H   H   H   Me   410       187   CO 2 Me                                 H   H   NO 2     H   Me   345       188   CO 2 Me                                 H   Cl   Cl   H   Me   668       189   CO 2 Me                                 H   H   NO 2     H   Me   413       190   CO 2 H                                 H   Cl   Cl   H   Me   544       191   CN                                 H   H   H   H   Me   565       192   CO 2 Me                                 H   Br   H   H   Me   606 (M + 23)       193   CO 2 Me                                 H   H   Br   H   Me   584       194   CO 2 Et                                 H   H   H   H   Me   373       195   CO 2 Et                                 H   H   H   H   Me   427       196   CO 2 Et                                 H   Cl   Cl   H   Me   587       197   CO 2 Et                                 H   H   H   H   Me   437       198   CO 2 Et                                 H   H   H   H   Me   389       199   CO 2 Et                                 H   H   H   H   Me   612       200   CO 2 Et                                 H   Cl   Cl   H   Me   449       201   CO 2 Me                                 H   Cl   Cl   H   Me   450       202   CO 2 Me                                 H   Cl   Cl   H   Me   465       203   CO 2 Me                                 H   H   H   H   Me   396       204   CO 2 Me                                 H                                 H   H   Me   473       205   CO 2 Me                                 H   H   H   H   Me   345       206   CO 2 Me                                 H   H   H   H   Me   359       207   CO 2 Me                                 H   Cl   Cl   H   Me   444       208   CO 2 Me                                 H   H   H   H   Me   355       209   CO 2 H                                 H   H   H   H   Me   366       210   CO 2 Me                                 H   Cl   Cl   H   Me   444       211   CO 2 Me                                 H   Cl   Cl   H   Me   430       212   CO 2 Me                                 H   H   H   H   Me   416       213   CO 2 Me                                 H   Cl   Cl   H   Me   430       214   CO 2 Me                                 H   H   H   H   Me   413       215   CO 2 Me                                 H   OMe   OMe   H   Me   418       216   CO 2 Me                                 H   OMe   OMe   H   Me   454       217   CO 2 Me                                 H   H   H   H   Me   362       218   CO 2 Me                                 H                                 H   H   Me   445       219   CO 2 Me                                 H   H   H   H   Me   359       220   CO 2 Me   —NHPh   H   H   H   H   Me   345       221   CO 2 Me                                 H   H   H   H   Me   423       222   CO 2 Me   2-Pyridyl   H   H   H   H   Me   353                                       (M + 23)       223   CO 2 Me                                 H   OMe   OMe   H   Me   459       224   CO 2 Me                                 H   Cl   Cl   H   Me   485       225   CO 2 Me                                 H   H   H   H   Me   345       226   CO 2 Me                                 H   H   NO 2     H   Me   420       227   CO 2 Me                                 H   H   NO 2     H   Me   420       228   CO 2 Me                                 H   H   H   H   Me   359       229   CO 2 Me                                 H   H   H   H   Me   396       230   CO 2 Me                                 H   OH   OH   H   Me   426       231   CO 2 Me                                 H   H   F   H   Me   376       232   CO 2 Me                                 H   H   NO 2     H   Me   461       233   CO 2 Me                                 H   Cl   Cl   H   Me   468       234   CO 2 Me                                 H   H   H   H   Me   373       235   CO 2 Me                                 H   H   H   H   Me   375       236   CO 2 Me                                 H   NO 2     H   H   Me   443       237   CO 2 Me                                 H   H   NO 2     H   Me   443       238   CO 2 Me                                 H   H   H   H   Me   398       239   CO 2 Me                                 H   Cl   Cl   H   Me   491       240   CO 2 Me                                 H                                 H   H   Me   509       241   CO 2 Me                                 H   H                                 H   Me   473       242   CO 2 Me                                 H   H                                 H   Me   509       243   CO 2 Me                                 H   H   H   H   Me   310       244   CO 2 Me                                 H                                 H   H   Me   524       245   CO 2 Me                                 H   H                                 H   Me   488       246   CO 2 Me                                 H   H   H   H   Me   308       247   CO 2 Me   i-Pr   H   H   H   H   Me   296       248   CO 2 Me                                 H   H   H   H   Me   336       249   CO 2 Me   Me   H   H   H   H   Me   268       250   CO 2 Me                                 H   H                                 H   Me   474       251   CO 2 Me                                 H   H                                 H   Me   487       252   CO 2 Me   N-Morpholino   H   H   H   H   Me   339       253   CO 2 Me                                 H   H   H   H   Me   337       254   CO 2 Me                                 H   H                                 H   Me   488       255   CO 2 Me                                 H                                 H   H   Me   474       256   CO 2 Me                                 H                                 H   H   Me   456       257   CO 2 Me                                 H                                 H   H   Me   431       258   CO 2 Me                                 H                                 H   H   Me   500       259   CO 2 Me                                 H                                 H   H   Me   499       260   CO 2 Me                                 H                                 H   H   Me   481       261   CO 2 Me                                 H   H                                 H   Me   500       262   CO 2 Me                                 H   H                                 H   Me   499       263   CO 2 Me                                 H   H                                 H   Me   431       264   CO 2 Me                                 H   H   H   H   NH 2     397 (M + 23)       265   CO 2 Me   Ph   H   H   H   H   NH 2     353 (M + 23)       266   CO 2 Me                                 H   H   H   H   NH 2     413 (M + 23)       267   CO 2 Me   2-Furyl   H   H   H   H   NH 2     321       268   CO 2 Me   3-Furyl   H   H   H   H   NH 2     321       269   CO 2 Me   2-Furyl   H   H   H   H   Me   320       270   CO 2 Me   2-Furyl   H   H   H   NH 2     Me   335       271   CO 2 Me   2-Furyl   NHOH   H   H   H   Me   351       272   CO 2 Et   2-Furyl   H   H   H   H   NH 2     335       273   CO 2 Et   2-Furyl   H   Br   H   H   NH 2     413       274   CO 2 Et   2-Furyl   H   H   Br   H   NH 2     413       275   CO 2 Et                                 H   H   H   H   Me   467       276   CO 2 Me                                 H   H                                 H   Me   481       277   CO 2 Me                                 H   H                                 H   Me   456       278   CO 2 Me                                 H                                 H   H   Me   473       279   CO2Me                                 H                                 H   H   Me   513       280   CO 2 Me                                 H                                 H   H   Me   516       281   CO 2 Me                                 H                                 H   H   Me   501       282   CO 2 Me                                 H                                 H   H   Me   566       283   CO 2 Me                                 H                                 H   H   Me   488       284   CO 2 Me                                 H   H                                 H   Me   541                    
III. Biological Assays and Activity
 
Ligand Binding Assay for Adenosine A2a Receptor
 
     Ligand binding assay of adenosine A2a receptor was performed using plasma membrane of HEK293 cells containing human A2a adenosine receptor (PerkinElmer, RB-HA2a) and radioligand [ 3 H]CGS21680 (PerkinElmer, NET1021). Assay was set up in 96-well polypropylene plate in total volume of 200 mL by sequentially adding 20 mL1:20 diluted membrane, 130 mLassay buffer (50 mM Tris-HCl, pH7.4 10 mM MgCl 2 , 1 mM EDTA) containing [3H] CGS21680, 50 mLdiluted compound (4×) or vehicle control in assay buffer. Nonspecific binding was determined by 80 mM NECA. Reaction was carried out at room temperature for 2 hours before filtering through 96-well GF/C filter plate presoaked in 50 mM Tris.HCl, pH7.4 containing 0.3% polyethylenimine. Plates were then washed 5 times with cold 50 mM Tris.HCl, pH7.4., dried and sealed at the bottom. Microscintillation fluid 30 ml was added to each well and the top sealed. Plates were counted on Packard Topcount for [ 3 H]. Data was analyzed in Microsoft Excel and GraphPad Prism programs. (Varani, K.; Gessi, S.; Dalpiaz, A.; Borea, P. A. British Journal of Pharmacology, 1996, 117, 1693) 
     Adenosine A2a Receptor Functional Assay 
     CHO-K1 cells overexpressing human adenosine A2a receptors and containing cAMP-inducible beta-galactosidase reporter gene were seeded at 40-50K/well into 96-well tissue culture plates and cultured for two days. On assay day, cells were washed once with 200 mL assay medium (F-12 nutrient mixture/0.1% BSA). For agonist assay, adenosine A2a receptor agonist NECA was subsequently added and cell incubated at 37 C., 5% CO 2  for 5 hrs before stopping reaction. In the case of antagonist assay, cells were incubated with antagonists for 5 minutes at R.T. followed by addition of 50 nM NECA. Cells were then incubated at 37C., 5% CO 2  for 5 hrs before stopping experiments by washing cells with PBS twice. 50 mL 1× lysis buffer (Promega, 5× stock solution, needs to be diluted to 1× before use) was added to each well and plates frozen at −20C. For b-galactosidase enzyme colormetric assay, plates were thawed out at room temperature and 50 mL 2× assay buffer (Promega) added to each well. Color was allowed to develop at 37C. for 1 hr. or until reasonable signal appeared. Reaction was then stopped with 150 mL 1M sodium carbonate. Plates were counted at 405 nm on Vmax Machine (Molecular Devices). Data was analyzed in Microsoft Excel and GraphPad Prism programs. (Chen, W. B.; Shields, T. S.; Cone, R. D. Analytical Biochemistry, 1995, 226, 349; Stiles, G. Journal of Biological Chemistry, 1992, 267, 6451) 
     Assay of Phosphodiesterase Activity 
     The assay of phosphodiesterase activity follows the homogeneous SPA (scintillation proximity assay) format under the principle that linear nucleotides preferentially bind yttrium silicate beads in the presence of zinc sulfate. 
     In this assay, the enzyme converts radioactively tagged cyclic nucleotides (reaction substrate) to linear nucleotides (reaction product) which are selectively captured via ion chelation on a scintillant-containing bead. Radiolabeled product bound to the bead surface results in energy transfer to the bead scintillant and generation of a quantifiable signal. Unbound radiolabel fails to achieve close proximity to the scintillant and therefore does not generate any signal. 
     Specifically, enzyme was diluted in PDE buffer (50 mM pH 7.4 Tris, 8.3 mM MgCl 2 , 1.7 mM EGTA) with 0.1% ovalbumin such that the final signal:noise (enzyme:no enzyme) ratio is 5-10. Substrate (2,8- 3 H-cAMP or 8- 3 H-cGMP, purchased from Amersham Pharmacia) was diluted in PDE (4, 5, 7A) buffer to 1 nCi per μl (or 1 μCi/ml). For each test well, 48μl of enzyme was mixed with 47μl substrate and 5 μl test compound (or DMSO) in a white Packard plate, followed by shaking to mix and incubation for 15 minutes at room temperature. A 50 μl aliquot of evenly suspended yttrium silicate SPA beads in zinc sulfate was added to each well to terminate the reaction and capture the product. The plate was sealed using Topseal-S (Packard) sheets, and the beads were allowed to settle by gravity for 15-20 minutes prior to counting on a Packard TopCount scintillation counter using a  3 H glass program with color quench correction. Output was in color quench-corrected dpm. 
     Test compounds were diluted in 100% DMSO to a concentration 20× final assay concentration. DMSO vehicle alone was added to uninhibited control wells. Inhibition (%) was calculated as follows:
 
Nonspecific binding (NSB)=the mean of CPM of the substrate+buffer+DMSO wells
 
Total Binding (TB)=the mean of the enzyme+substrate+DMSO wells
 
         %   ⁢           ⁢   Inhibition   ⁢           ⁢   listed   ⁢           ⁢   in   ⁢           ⁢   Table   ⁢           ⁢   1     =         (     1   -     (       Sample   ⁢           ⁢   CPM     -   NSB     )       )       TB   -   NSB       ×   100.         
 
     The IC 50  values were calculated using the Deltagraph 4-parameter curve-fitting program. The IC 50  and % Inhibition data on PDE 4, 5, and 7A are listed for the indicated compounds in Table 2 below. 
     
       
         
               
             
               
               
               
             
               
               
               
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 
                   
                             
                     
                         
                         
                     
                   
                 
               
             
          
           
               
                   
                 MS 
                 IC 50 (μM)/% inh.@μM 
               
             
          
           
               
                 No. 
                 R 1   
                 R 2   
                 R 3a   
                 R 3b   
                 R 3c   
                 R 3d   
                 R 4   
                 (M + 1) 
                 PDE7A 
                 PDE4 
                 PDE5 
               
               
                   
               
             
          
           
               
                 6 
                 CO 2 H 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 360 
                 45%@ 20 
                 49%@5 
               
               
                 51 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 358 
                 0.055 
                 0.353 
                 2.7 
               
               
                 56 
                 CO 2 Et 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 NHAc 
                 H 
                 Me 
                 445 
                 0.074 
                 0.333 
                 2.5 
               
               
                 70 
                 CO 2 Et 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 i- Pr 
                 400 
                 2.11 
               
               
                 73 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Et 
                 372 
                 1.54 
                   
                 0.998 
               
               
                 82 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 NH 2   
                 H 
                 H 
                 Me 
                 373 
                 0.021 
                 0.204 
                 1.11, 0.864 
               
               
                 90 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 NH 2   
                 H 
                 H 
                 Me 
                 409 
                 0.005 
                 0.237, 0.172 
                 2.33 
               
               
                 98 
                 CN 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 361 
                 1.13 
               
               
                 119 
                 CONHMe 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 393 
                 0.658 
                   
                 41%@ 20 
               
               
                 133 
                 Ac 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 472 
                 1.54 
               
               
                 134 
                 Ac 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 342 
                 1.14 
               
               
                 169 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 NO 2   
                 H 
                 Me 
                 551 
                 0.0053 
                   
                 0.184 
               
               
                 170 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 Cl 
                 Cl 
                 H 
                 Me 
                 573 
                 0.0087 
                   
                 0.557 
               
               
                 190 
                 CO 2 H 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 Cl 
                 Cl 
                 H 
                 Me 
                 544 
                 5.9 
               
               
                 191 
                 CN 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 565 
                 0.593 
               
               
                 197 
                 CO 2 Et 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 437 
                 0.728 
                 69%@5 
                 0.362 
               
               
                 219 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 359 
                 0.964 
                 61%@5 
                 1.1 
               
               
                 220 
                 CO 2 Me 
                 —NHPh 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 345 
                 0.084 
                 1.8 
                 0.637 
               
               
                 241 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 Me 
                 473 
                 0.0035 
                 0.954 
                 0.183 
               
               
                 242 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 Me 
                 509 
                 0.0038 
                 0.782 
                 0.141 
               
               
                 243 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 310 
                 2.6 
               
               
                 245 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 Me 
                 488 
                 0.0053 
                 0.875 
                 0.185 
               
               
                 248 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 336 
                 0.783 
                 0.171 
                 0.649 
               
               
                 250 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 Me 
                 474 
                 0.0074 
                 0.684 
                 2.4 
               
               
                 251 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 Me 
                 487 
                 0.0054 
                 0.754 
                 0.26 
               
               
                 253 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 337 
                 0.905 
                 0.85 
                 0.303 
               
               
                 254 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 Me 
                 488 
                 0.0067 
                 0.664 
                 0.765 
               
               
                 261 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 Me 
                 500 
                 0.0063 
                 0.477 
                 0.63 
               
               
                 262 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 Me 
                 499 
                 0.008 
                 0.702 
                 3.7 
               
               
                   
               
             
          
         
       
     
     
       
         
               
             
               
               
             
               
               
               
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 3 
               
             
             
               
                   
               
               
                 
                   
                             
                     
                         
                         
                     
                   
                 
               
             
          
           
               
                   
                 Ki(nM) 
               
             
          
           
               
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
                 A2a 
                   
               
               
                   
                   
                   
                   
                   
                   
                   
                   
                 MS 
                 A2a 
                 antagonist 
                 A1 
               
               
                 No. 
                 R 1   
                 R 2   
                 R 3a   
                 R 3b   
                 R 3c   
                 R 3d   
                 R 4   
                 (M + 1) 
                 binding 
                 function 
                 binding 
               
               
                   
               
             
          
           
               
                 14 
                 CO 2 Et 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 454 
                 451 
               
               
                 22 
                 CO 2 Et 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 NH 2   
                 411 (M + 23) 
                 70 
                 253 
               
               
                 18 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 374 
                 159 
                 &gt;1000 
                 584 
               
               
                 27 
                 CO 2 Et 
                 Ph 
                 H 
                 H 
                 H 
                 H 
                 NH 2   
                 345 
                 42 
                 36 
                 554 
               
               
                 23 
                 CO 2 Et 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 388 
                 251 
               
               
                 275 
                 CO 2 Et 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 467 
                 263 
               
               
                 41 
                 CO 2 Et 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 334 
                 271 
               
               
                 57 
                 CO 2 Et 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 358 
                 400 
               
               
                 67 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 344 
                 39 
                 128 
                 1853 
               
               
                 66 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 344 
                 46 
                 151 
                 1591 
               
               
                 85 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 431 (M + 23) 
                 35 
                 &gt;1000 
                 5570 
               
               
                 82 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 NH 2   
                 H 
                 H 
                 Me 
                 373 
                 294 
               
               
                 95 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 NH 2   
                 395 
                 286 
               
               
                 135 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 331 
                 123 
               
               
                 130 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 345 
                 222 
               
               
                 141 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 346 
                 172 
               
               
                 183 
                 CO 2 Et 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 387 
                 191 
               
               
                 208 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 355 
                 171 
               
               
                 197 
                 CO 2 Et 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 437 
                 148 
               
               
                 217 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 362 
                 119 
               
               
                 221 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 423 
                 76 
                 258 
                 2180 
               
               
                 222 
                 CO 2 Me 
                 2-Pyridyl 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 353 (M + 23) 
                 237 
               
               
                 198 
                 CO 2 Et 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 389 
                 185 
               
               
                 199 
                 CO 2 Et 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 612 
                 301 
               
               
                 279 
                 CO2Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 Me 
                 513 
                 179 
               
               
                 261 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 Me 
                 500 
                 472 
               
               
                 280 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 Me 
                 516 
                 237 
               
               
                 276 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 Me 
                 481 
                 304 
               
               
                 258 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 Me 
                 500 
                 211 
               
               
                 281 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 Me 
                 501 
                 201 
               
               
                 262 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 Me 
                 499 
                 332 
               
               
                 184 
                 CO 2 Et 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 373 
                 140 
               
               
                 195 
                 CO 2 Et 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 427 
                 171 
               
               
                 260 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 Me 
                 481 
                 163 
               
               
                 263 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 Me 
                 431 
                 480 
               
               
                 245 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 Me 
                 488 
                 276 
               
               
                 264 
                 CO 2 Me 
                 
                   
                             
                     
                         
                         
                     
                   
                 
                 H 
                 H 
                 H 
                 H 
                 NH 2   
                 397 (M + 23) 
                 342 
               
               
                 265 
                 CO 2 Me 
                 Ph 
                 H 
                 H 
                 H 
                 H 
                 NH 2   
                 353 
                 50 
               
               
                   
                   
                   
                   
                   
                   
                   
                   
                 (M + 23) 
               
               
                 267 
                 CO 2 Me 
                 2-Furyl 
                 H 
                 H 
                 H 
                 H 
                 NH 2   
                 321 
                 &lt;15 
               
               
                 268 
                 CO 2 Me 
                 3-Furyl 
                 H 
                 H 
                 H 
                 H 
                 NH 2   
                 321 
                 21 
               
               
                 269 
                 CO 2 Me 
                 2-Furyl 
                 H 
                 H 
                 H 
                 H 
                 Me 
                 320 
                 192 
               
               
                 270 
                 CO 2 Me 
                 2-Furyl 
                 H 
                 H 
                 H 
                 NH 2   
                 Me 
                 335 
                 303 
               
               
                 271 
                 CO 2 Me 
                 2-Furyl 
                 NH 
                 H 
                 H 
                 H 
                 Me 
                 351 
                 276 
               
               
                   
                   
                   
                 OH 
               
               
                 272 
                 CO 2 Et 
                 2-Furyl 
                 H 
                 H 
                 H 
                 H 
                 NH 2   
                 335 
                 &lt;5 
               
               
                 273 
                 CO 2 Et 
                 2-Furyl 
                 H 
                 Br 
                 H 
                 H 
                 NH 2   
                 413 
                 279 
               
               
                 274 
                 CO 2 Et 
                 2-Furyl 
                 H 
                 H 
                 Br 
                 H 
                 NH 2   
                 413 
                 143