bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of 4‐chloro‐7‐ethoxy‐2(3H)‐benzoxazolone‐6‐carboxylic acid
Authors: Kato Shiro , Morie Toshiya 
Published: March 2009

AbstractAs a part of metabolic studies of mosapride (1), a potential gastroprokinetic agent, the synthesis of 4‐chloro‐7‐ethoxy‐2(3H)‐benzoxazolone‐6‐carboxylic acid (7) as a derivative of 4‐amino‐5‐chloro‐2‐ethoxy‐3‐hydroxybenzoic acid (6), which has served a benzoic acid part of the metabolites 4 and 5, is described. Treatment of methyl 3‐amino‐4‐substituted amino‐5‐chloro‐2‐ethoxybenzoate derivatives 11a‐c with sodium nitrate in acidic medium gave the benzotriazole derivatives 13x,y instead of the objective 3‐hydroxy counterpart. The synthesis of 7 started from o‐vanillin acetate (15) and proceeded through the intermediates 2‐hydroxy‐3‐methoxy‐4‐nitrobenzaldehyde (18), methyl 4‐amino‐2,3‐dihydroxybenzoate (23), and methyl 7‐hydroxy‐2(3H)‐benzoxazolone‐6‐carboxylate (30). Compound 30 was alternatively prepared from 23 via methyl 4‐ethoxycarbonylamino‐2‐ethoxycarbonyloxy‐3‐hydroxybenzoate (29), which is the product resulting from the migration of the ethoxycarbonyl group of methyl 4‐amino‐2,3‐diethoxycar‐bonyloxybenzoate (27).
New anti‐tumor agents. 1. Heterocyclic benzodioxole lactones
Authors: Jurd Leonard 
Published: March 2009

AbstractMorpholino Mannich bases of types 5, 12 react with tetronic acid in aqueous acetic acid to yield uncyclized lactones of types 7, 13. Acetylation and methylation of these products yields monoacetyl‐monomethyl derivatives which can then be cyclized in alkali to give unsaturated lactones of types 8, 16 and saturated lactones 9b, 15. The hydroxylactone 9a can be synthesized directly by reaction of 3,4,5‐trimethoxybenzaldehyde with sesamol and tetronic acid in methanol. With few exceptions the lactones of type 8 and 16 have proven to be active inhibitors of tumor growth in the National Cancer Institute in vitro screening program against 60 diverse human cancer cell lines. The lactone 8 is particularly potent, inhibiting in vitro growth of some cancers at concentrations as low as 10−6‐10−7 moles/1.
Synthesis and reactivity of oxopyrrolidinothieno[2]azepinones: [3]Benzazepine antidepressant analogs
Authors: Mamouni AÏCha , Daïch Adam , Decroix Bernard 
Published: March 2009

AbstractA synthesis of oxopyrrolidino[2]azepinones annelated to a thiophene ring 3a,b,c is described starting from succinimide and halogenomethylthiophenes 6a,b,c. Stereoselective reduction, Schmidt reaction and the Beckmann rearrangement of the oximes of the ketones 3a,b,c are studied.
Synthesis of nitrogen‐containing heterocycles. 7 Reaction of aliphatic diaminomethylenehydrazones with hindered ethoxymethylenecyanoacetate
Authors: Miyamoto Yoshiko , Yamazaki Chiji 
Published: March 2009

AbstractAliphatic diaminomethylenehydrazones 1 were reacted with ethyl 2‐cyano‐3‐ethoxy‐2‐pentenoate 2 to give a number of heterocycles in low to moderate yields, according to the substitution pattern and the size of substituent. When 1 carried a single methyl group on the terminal nitrogen, it gave preferentially 6‐oxo‐1,6‐dihydropyrimidines 4 incorporating N(4) into the ring. In contrast, the reaction between 1c or 1d and 2 led to 6‐imino‐ and 6‐oxo‐1, 6‐dihydropyrimidines 7 and 8 along with 3. When the alkylidene moiety was bulky, 1e and 1f, the similar reaction gave 3 in high yields without any cyclized product. Upon exposure to acid, compound 3 yielded 6‐oxo‐1,6‐dihydropyrimidines 6, [1,2,4]triazolo[1,5‐c]pyrimidine‐8‐carboxylate 5 and N‐alkenyl‐1,2,4‐triazoles 9 in addition to 7 and 8 in proportions dictated by the nature of the substituents of 1. The structural assignment and reaction mechanism are discussed.
Rearrangements of 5‐acetyl‐3‐benzoylamino‐6‐(2‐dimethylamino‐1‐ethenyl)‐2H‐pyran‐2‐one and 3‐benzoylamino‐6‐(2‐dimethylamino‐1‐ethenyl)‐5‐ethoxycarbonyl‐2H‐pyran‐2‐one into 1‐aminopyridine, pyrano[2,3‐b]pyridine and isoxazole derivatives
Authors: Strah Sonja , Svete Jurij , Stanovnik Branko 
Published: March 2009

AbstractRearrangements of 5‐acetyl‐3‐benzoylamino‐6‐(2‐dimethylamino‐1‐ethenyl)‐2H‐pyran‐2‐one (1) and 3‐benzoylamino‐6‐(2‐dimethylamino‐1‐ethenyl)‐5‐ethoxycarbonyl‐2H‐pyran‐2‐one (7) in the presence of N‐nucleophiles, such as ammonia, hydrazine, and hydroxylamine, into 1‐aminopyridine, pyrano[2,3‐b]‐pyridine, and isoxazole derivatives 5, 11, and 15 is described. In the reaction of compounds 1 and 7 with C‐nucleophiles, such as 5,5‐dimethyl‐1,3‐cyclohexanedione and barbituric acid, only substitution of the dimethylamino group is taking place to give the compounds 17, 18, and 20.
The birch reduction of heterocyclic compounds. 11. Birch reduction and reductive alkylation of furamides
Authors: Kinoshita Takamasa , Icbinari Daisuke , Sinya Junko 
Published: March 2009

AbstractThe Birch reduction‐alkylation of some N,N‐dialkylfuramides and its application to the useful intermediates for the natural product synthesis are described.
Synthesis of steroidal extranucleo 1,3,4‐oxadiazoles
Authors: Siddiqui A. U. , Satyanarayana Y. , Ahmed I. , Siddiqui A. H. 
Published: March 2009

AbstractCholest‐5en‐3β‐ol 1, 3,3‐ethylenedioxy‐androst‐4‐en‐17β‐ol 2 and 17,17‐ethylenedioxy‐1,3,5(10)‐estratrien‐3β‐ol 3 were converted into ethyl ester 1a, 2a and 3a by reaction with ethyl chloroacetate in the presence of potassium. The ethyl esters 1a, 2a and 3a on reaction with hydrazine gave hydrazides 1b, 2b and 3b, which on reaction with cyanogen bromide afforded 1,3,4‐oxadiazoles 1c, 2c and 3c.
Synthesis of mono‐cationic and dicationic analogs of hoechst 33258
Authors: Czarny Agnieszka , Wilson W. D. , Boykin David W. 
Published: March 2009

AbstractThe synthesis of fourteen mono‐cationic and six dicationic analogs of Hoechst 33258 is described. The monocationic benzimiazoles 7a‐7g and the dicationic benzimidazoles 9a‐9c are obtained in five steps starting from 4‐acetamidobenzonitrile. The monocationic bis‐benzimiazoles 12a‐12g are synthesized in four steps starting from 4‐amino‐3‐nitrobenzonitrile. The dicationic bis‐benzimiazoles 17a‐17c are obtained in six steps starting from 4‐amino‐3‐nitrobenzonitrile.
Synthesis and oxygen‐atom transfer reactions of 3‐hydroperoxy‐3,4,4,5,5‐pentasubstituted‐1,2‐dioxolanes
Authors: Baumstark A. , Chen Y.‐X. , Rodriguez A. 
Published: March 2009

AbstractA series of 3‐hydroperoxy‐3,4,4,5,5‐pentasubstituted‐1,2‐dioxolanes 2a‐d were synthesized in good yield from the corresponding 3‐hydroxy‐1,2‐dioxolanes by reaction with concentrated hydrogen peroxide in acetonitrile with p‐toluenesulfonic acid as catalyst. The 3‐hydroperoxy‐1,2‐dioxolanes were effective oxygen‐atom transfer reagents for the oxidation of thioanisole, triethylamine and 2,3‐dimethyl‐2‐butene to the sulfoxide, N‐oxide and epoxide, respectively. The reactions occurred under mild conditions and were found to be of the second order overall. The second order rate constants (k2) were determined for oxidation of thioanisole by 2a‐d in deuteriochloroform. For 2a, k2 values for N‐oxidation and epoxidation were also measured. The 3‐hydroperoxy‐1,2‐dioxolanes were found to be less reactive than the structurally similar cyclic α‐azohydroperoxides but much more reactive than simple hydroperoxides. The mechanism of oxygen‐atom transfer is postulated to occur via nucleophilic attack of the substrate on the terminal oxygen of the hydroperoxide. Intramolecular hydrogen bonding of the hydroperoxy proton to a dioxolane oxygen appears to account for the reaction order in aprotic media.
Synthesis and tautomerism of 2‐aryl‐ and 2‐heteroaryl derivatives of benzimidazole
Authors: Lee In‐Sook Han , Jeoung Eun Hee , Lee Chang Kiu 
Published: March 2009

AbstractBenzimidazoles containing furyl and thienyl substituents at C‐2 were prepared by condensation of o‐phenylenediamine and corresponding carboxylic acids in the presence of polyphosphoric acid. The 2‐heteroarylbenzimidazoles showed tautomerism in dimethyl sulfoxide solution while 2‐phenylbenzimidazole did not. The tautomerism appeared to be taking place by intermolecular relay of protons between stacked molecules.
Synthesis of 1‐(2‐hydroxyphenyl)‐2,4‐imidazolidinedione derivatives through cyclic transformations of ethyl 2‐oxo‐3(2H)‐benzoxazoleacetate derivatives
Authors: Milcent René , Akhnazarian Anna , Lensen Nathalie 
Published: March 2009

AbstractA series of ethyl 2‐oxo‐3(2H)‐benzoxazoleacetate derivatives 2 have been synthesized. By reaction with ammonia, primary amines or hydrazine, these compounds 2 were transformed into 1‐(2‐hydroxyphenyl)‐2,4‐imidazolidinedione derivatives 4, 5 and 6, respectively. Some of these new hydantoins 4, treated with phosphorus oxychloride, gave 3H‐2‐oxoimidazo[2,1‐b]benzoxazole derivatives 9. Ethyl 2‐oxo‐3(2H)‐benzoxazolepropionate (10) was prepared by a Michaël reaction of ethyl acrylate with 2‐benzoxazolone (1a). With 10, no cyclic transformation was observed in the presence of ammonia or alkylamine.
Iminium carbonic acid derivative salts. XI. Synthesis of N,S‐containing heterobicycles from N‐protected 2‐methylthio‐1,3‐thiazinium and 2‐methylthiothiazoüum salts. Part 3. Reaction of N‐protected 2‐methylthio‐1,3‐thiazinium and 2‐methylthiothiazolium salts with 3‐amino‐2‐cyano‐3‐arylacrylonitriles
Authors: Hanefeld Wolfgang , Naeeni Mahmoud , Schlitzer Martin 
Published: March 2009

AbstractN‐Boc‐protected 2‐memylthio‐1,3‐thiazinium 1 and 2‐methylthiothiazolium iodides 2, 3 obtained from the corresponding 3,4,5,6‐tetrahydro‐2H‐1,3‐thiazine‐2‐thiones and thiazolidine‐2‐thiones by the action of methyl iodide were reacted with 3‐armno‐2‐cyano‐3‐arylacrylonitriles forming the cyclic isothioureas 5–7. The protection group was removed with trifluoroacetic acid whereupon the desired cyclisation to 3,4‐dihydro‐2H,6H‐pyrimido[2,1‐b][1,3]thiazines 8a‐c, 8a′‐c′ and thiazolo[3,2‐b]pyrimidines 9a,b, 9a′,b′, 10a,b took place.
Furopyridines. XVIII. Photocycloaddition of furo[2,3‐c]pyridin‐7(6H)‐one with acrylonitrile
Authors: Shiotani Shunsaku , Tsukamoto Youichi , Kawahara Yukiko , Saitoh Hideo , Ishida Toshimasa , In Yasuko 
Published: March 2009

AbstractThe photocycloaddition of furo[2,3‐c]pyridin‐7(6H)‐one (1) and its N‐mefhyl derivative (1‐Me) to acrylonitrile has been studied. The structures of the photoadducts isolated by colum chromatography were determined by the nuclear magnetic resonance spectroscopy and single crystal X‐ray analysis. The cyclo‐addition of 1 afforded an adduct 2 at the carbonyl oxygen and 8‐cyano‐8,9‐dihydrofuro[d]azocin‐7(6H)‐one (3), and the addition of 1‐Me the N‐methyl derivative 3‐Me of 3, (9S*)‐9‐cyano‐6‐methyl‐3a,7a‐dihydro‐3a,7a‐ethanofuro[2,3‐c]pyridin‐7(6H)‐one (4), (2S*, 2aR*, 7bR*)‐ (5) and (1R*, 2aS*, 7bS*)‐2‐cyano‐3‐methyl‐4‐oxo‐1,2,2a,3,4,7b‐hexahydrocyclobuta[e]furo[2,3‐c]pyridine (6).
Synthesis of new pyridine intermediates as precursors for the elaboration of streptonigrin analogues by the metalation‐cross‐coupling strategy
Authors: Pomel V. , Rovera J. C. , Godard A. , Marsais F. , Quéguiner G. 
Published: March 2009

AbstractStarting from available 2‐amino‐6‐chloro‐3‐nitropyridine, synthesis of 3‐amino‐6‐pyridinecarboxylic acid derivatives precursor for pyridine ring C of streptonigrin analogues is described.
Preparation of triazamacrocycles containing only secondary amine functions using both tosyl and boc protecting groups
Authors: Krakowiak Krzysztof E. , Yi Guoliang , Bradshaw Jerald S. 
Published: March 2009

Abstract1,8,15‐Triazacycloheneicosane (1); 1,9,17‐triazacyclotetracosane (2) and 1,10,19‐triazacycloheptacosane (3) were prepared by treating the appropriate N,N‐bis(ω‐bromoalkyl)toluenesulfonamide 8–10 with the appropriate N,N′‐ditosyl‐α,ω‐diaminoalkane 11–13 in dimethylformamide using sodium hydride as the base followed by phenol and 33% hydrobromic acid in acetic acid to remove the tosyl protecting groups. 2‐Allyloxymethyl‐4,11,18‐ triazaoxacycloheneicosane (4) was prepared in two ways. First, N,N′,N″‐tritosylbis(hexamemylene)triamine (18) was treated with 2‐allyloxymethyl‐3‐oxa‐1,6‐hexanediol ditosylate (23) and cesium carbonate in dimethylformamide followed by sodium amalgam to remove the tosyl protecting groups. The second preparation of 4 was done by treating the tri‐BOC analog of 18 with 23 followed by hydrochloric acid in isopropyl alcohol to remove the BOC protecting groups. The overall yields of 4 using these two processes were very close.
Synthesis and anticonvulsant activity of 2‐aryl‐3,4‐dialkyltetrahydro‐1,3,4‐oxadiazines and 2‐aryl‐3,4‐dialkyltetrahydro‐1,3,4‐oxadiazin‐5‐ones
Authors: Kornet Milton J. 
Published: March 2009

AbstractSeveral 2‐aryl‐3,4‐dialkyltetrahydro‐1,3,4‐oxadiazines have been synthesized from 2‐(1,2‐dialkylhydrazino)ethanol (2) and aromatic aldehydes. Also, three 2‐aryl‐3,4‐dialkyltetrahydro‐1,3,4‐oxadiazin‐5‐ones were obtained from the reaction of 1,2‐dialkylglycolylhydrazine (5) and aromatic aldehydes. These compounds exhibited activity in the maximal electroshock seizure test.
Conformational behavior on 2,2,3‐trisubstituted 1,2,3,4‐tetrahydroquinoline alkaloids, virantmycin, benzastatins, and their congeners, evaluated by semi‐empirical molecular orbital calculations
Authors: Morimoto Yoshiki 
Published: March 2009

AbstractThe conformational behaviors on ring inversion between two half‐chair conformers a and b in physiologically active 2,2,3‐trisubstituted 1,2,3,4‐tetrahydroquinoline alkaloids, virantmycin (1), benzastatin C (6), benzastatin D (7), and their congeners 2–5, which were revealed by their nmr studies have been quantitatively evaluated by semi‐empirical molecular orbital calculations (PM3). The geometries of respective half‐chair conformers a and b in compounds 1–7 were optimized and it was found that their thermodynamic distributions are approximately valid in comparison with the coupling constants observed in their nmr experiments. Furthermore, these calculations estimated the energy barriers for ring inversion in compounds 1–7 in the range of ca. 4.86–11.13 kcal/mol, which were compatible with rapid interconversions between a and b at room temperature.
Synthesis of nonsymmetrically 3,4‐disubstituted 1,2,5‐thiadiazole dioxides
Authors: Martinez Ana , Castro Ana , Arán Vicente J. , Cardelús Ignacio , Llenas Jesús , Palacios José M. 
Published: March 2009

AbstractA synthetic pathway for obtaining arylamino, alkylamino 3,4‐disubstituted 1,2,5‐thiadiazole dioxide derivatives has been developed. This methodology could be applied to obtain potential biologically active molecules.
New isomeric N‐substituted hydrazones of 2‐, 3‐and 4‐pyridinecarboxaldehydes
Authors: Wyrzykiewicz Elżbieta , Prukała Dorota 
Published: March 2009

AbstractEighteen compounds unknown in the literature, N‐(E)‐stilbenyloxyalkylcarbonyl‐ and N‐(E)‐stilbenyloxyalkylcarbonylaminoalkylcarbonyl‐substituted hydrazones of 2‐, 3‐ and 4‐pyridinecarboxaldehydes have been prepared. The stereochemical behavior of these compounds in dimethyl‐d6 sulfoxide solution has been studied by 1H‐nmr technique. The E geometrical isomers and cisltrans amide conformers have been found for N‐substituted‐hydrazones 1–16.
Synthesis and reactions of 1,3‐dicarbonyl‐substituted troponoids: Conversion to tropolones having an isoxazole or a pyrazole ring
Authors: Nasu Tomoyuki , Tagawa Tomoko , Imafuku Kimiaki 
Published: March 2009

Abstract3‐Acetyltropolone (1) was treated with diethyl oxalate in the presence of sodium ethoxide to afford 3‐(2‐ethoxalyl‐1‐oxoethyl)tropolone (2) as a minor product and its cyclized 2‐ethoxycarbonyl‐4,9‐dihydrocyclohetpa[b]pyran‐4,9‐dione (3) as the major one. The former was readily converted to the latter. Then, as a stable synthon bearing a 1,3‐dicarbonyl group, 2‐(2‐ethoxalyl‐1‐oxoethyl)‐7‐methylaminotropone (5) was prepared. The reactions of compound 5 with hydroxylamine, hydrazine, and methylhydrazine were carried out to give troponoids possessing an isoxazole or a pyrazole ring. The parent compounds, 3‐(3‐pyrazolyl)tropolone (13) and 3‐(1‐methylpyrazol‐3‐yl)tropolone (21), were obtained via hydrolysis and decarboxylation. Similarly, 2‐ethoxycarbonyl‐4,9‐dihydrocyclohepta[b]pyran‐4,9‐dione (3) reacted with hydroxylamine, hydrazine, and methylhydrazine to yield troponoids possessing a heterocyclic ring.
Facile synthesis of benzene‐bridged azaoxamacrobicyclic ligands
Authors: Bradshaw Jerald S. , Krakowiak Krzysztof E. 
Published: March 2009

AbstractFive new barrel‐shaped macrobicyclic compounds capable of complexation with anions have been prepared. Intermediate triamines were prepared in one‐step using a triple Mitsonobu reaction, thereby shortening the overall synthetic sequence. A previously prepared benzene‐bridged hexaazamacrocycle was prepared in only four‐steps.
Acylation of 5‐amino‐3H‐1,3,4‐thiadiazolin‐2‐one
Authors: Ra Do Young , Cho Nam Sook , Cho Jae Joo 
Published: March 2009

AbstractAcylation of 5‐amino‐3H‐1,3,4‐thiadiazolin‐2‐one (2) was undertaken selectively at either the 3‐NH position or at 5‐amino group depending on reaction conditions. The 3‐NH is highly acidic and acylation takes place with acid anhydrides at this position in high yields in the presence of pyridine or triethylamine. The diacylation of both the 3‐position and the 5‐amino group was only possible via the 5‐amino‐3‐acyl‐1,3,4‐thiadiazolin‐2‐one intermediates 4. Under neutral conditions, acylation only occurs at the 5‐amino group with acyl chlorides forming 5‐acylamino‐3H‐1,3,4‐thiadiazolin‐2‐ones 5. 5‐Acetylamino‐3H‐1,3,4‐thiadiazolin‐2‐one can also be synthesized by the thermal transformation of 5‐amino‐3‐acetyl‐1,3,4‐thiadi‐azolin‐2‐one in acetic acid.
Functionalization of 4,5‐dihalopyridazin‐6‐ones using 1‐(1,1‐dibromo‐2‐oxopropyl) derivatives
Authors: Kang Young‐Jin , Chung Hyun‐A , Kweon Deok‐Heon , Cho Su‐Dong , Lee Sang‐Gyeong , Kim Sung‐Kyu , Yoon Yong‐Jin 
Published: March 2009

AbstractFunctionalization of 4,5‐dihalopyridazin‐6‐ones using 1‐(1,1‐dibromo‐2‐oxopropyl)‐4,5‐dihalopyridazin‐6‐ones with some nucleophiles gave regioselectively only 5‐halo‐4‐substituted‐pyridazin‐6‐ones.
Synthesis and structure of novel 1,2‐dihydro‐phthalazine containing betaines
Authors: Saczewski Franciszek , Gdaniec Maria 
Published: March 2009

Abstract1,2‐Dihydro‐2‐(4,5‐dihydroimidazol‐2yl)phthalazin‐1‐ol 1 reacts exothermically with dialkyl acetylenedicarboxylates to give 3‐[2‐(4,5‐dihydro‐1H‐imidazol‐3‐iurn‐2‐yl)‐1,2‐dihydro‐1‐phthalazin]‐1,4‐dialkoxy‐1,4‐dioxo‐2‐buten‐2‐olates 7 and 8. Enolic ester compounds underwent further transesterification reactions with formation of the betaines 9 and 10. The unequivocal structural assignement of these compounds was achieved by spectroscopic 1H and 13C nmr methods as well as X‐ray analysis of 7.
Synthesis of functionalized 3‐pyridyl methyl ketones
Authors: Wright S. W. , Hageman D. L. , McClure L. D. 
Published: March 2009

AbstractA synthesis of 3‐pyridyl methyl ketones is described that employs a palladium‐catalyzed olefination of 3‐bromopyridines with butyl vinyl ether followed by acid hydrolysis of the intermediate pyridyl vinyl ether in situ. This method has been applied to bromoquinoline substrates as well. The reaction is compatible with a variety of functional groups.
Synthesis of five‐membered 2‐heteroaryl 2‐heteroaromatic carboxylates and attempted cyclization to bisheteroaryl[2,3‐b:3′,2′‐d]pyran‐2‐one
Authors: Lee Chang Kiu , Yu Ji Sook , Kim Sun Hee 
Published: March 2009

Abstract2‐Heteroaryl 2‐heteroaromatic carboxylates were prepared by reactions of 2‐heteroaromatic carbonyl chlorides and 2(5H)‐furanone, 2(5H)‐thiophenone, and 1‐methyl‐2(5H)‐pyrrolone in triethylamine. The 1H nmr spectra of the esters showed that the electronic effect of both heteroaromatic rings did not cause any sizable shift from each other except for 1‐methyl‐2‐pyrrolyl 1‐methyl‐2‐pyrrolecarboxylate (5c). Attempts to cyclize the esters to heteroaryl‐fused pyran‐2‐ones were unsuccessful. The results may be explained by the most stable conformation of the esters in which two heteroatoms are anti along the C0 bond of the ester group.
Formation of basic compounds during the indole cyclization of ketone phenylhydrazones
Authors: Boido Caterina Canu , Boido Vito , Novelli Federica , Sparatore Fabio 
Published: March 2009

AbstractOn the basis of previous occasional findings, the Fischer indole cyclization of ten ketone phenylhydrazones containing moieties of increasing bulkiness was investigated in order to isolate eventual side products. In the cases of the three 2‐, 3‐ and 4‐acetylpyridine phenylhydrazones the corresponding 2‐pyridylindoles were the sole compounds so far isolated. In all the remaining cases, beside the indoles a mixture of basic compounds was obtained. In all cases aniline and a 2‐substituted (2‐methyl or 2‐phenyl)benzimidazole were formed, the last resulting through an apparent ortho‐semidinic rearrangements of phenylhydrazones. Starting from methyl isopropyl ketone phenylhydrazone a compound of formula C11H15NO was also isolated, to which the structure of 3‐(4‐aminophenyl)‐3‐methylbutanone was assigned on the basis of ir, nmr spectra and of the chemical reactivity. The formation of this compound seems related to a para‐benzidine‐like rearrangement of phenyl hydrazone.
A short and stereoselective synthesis of carbocyclic alpha‐l‐dideoxyhomonucleosides
Authors: Girard F. , Lee M.‐G. , Agrofoglio L. A. , Fridland A. 
Published: March 2009

AbstractA stereoselective five‐step total synthesis of the hitherto unknown carbocyclic alpha‐L‐dideoxyhomonu‐cleosides starting from readily available (1R,5S)‐2‐oxabicyclo[3.3.0]oct‐6‐en‐3‐one is described.
Synthesis and biological activity of 1,5‐dihydropyridazino‐[3,4‐b]quinoxalines and a new class of quinolones
Authors: Kurasawa Yoshihisa , Kim Ho Sik 
Published: March 2009

AbstractA new class of quinolones, 1,4‐dihydro‐4‐oxopyridazino[3,4‐b]quinoxaline‐3‐carboxylic acids and related compounds, were synthesized via oxidation of 1,5‐dihydropyridazino[3,4‐b]quinoxalines obtained from 2‐hydrazinoquinoxaline 4‐oxides. Some of the 1,5‐dihydropyridazino[3,4‐b]quinoxalines, 1,4‐dihydro‐4‐oxopyridazino[3,4‐b]quinoxaline‐3‐carboxylic acids, and related compounds showed biological activity.
Design, synthesis, and photophysical characterization of novel pentacyclic red shifted azine dyes
Authors: Gloster Daniel F. , Cincotta Louis , Foley James W. 
Published: March 2009

AbstractAs part of our continuing efforts to develop second generation photodynamic therapeutic agents [1], we synthesized three pentacyclic azine dyes that were designed with the aid of MNDO calculations to absorb visible light having wavelengths longer than 600 nm. Photophysical measurements for the azine dyes 1,4,8,11‐tetraethyl‐1,2,3,4,8,9,10,11,13‐nonahydrodipyrazino[2,3‐b:2′, 3′‐i] phenazinium acetate, 13, 1,4,8,11‐tetraethyl‐2,3,4,8,9,10,11,12,13‐octahydro‐13‐methyldipyrazino[2,3‐b:2,3′‐i]phenazinium iodide, 14, and l,4,8,11,13‐pentaethyl‐2,3,4,8,9,10,11,12,13‐octahydrodipyrazino[2,3‐b:2′,3′‐i]phenazinium iodide, 15, are highlighted by a 35 nm red shift in their absorption spectra and a 5–7 fold increase in their singlet oxygen quantum yield relative to tricyclic model compounds 3,7‐bis(diethylamino)phenazinium chloride, 20, and 3,7‐bis(diethylamino)‐5‐ethyl‐phenazinium iodide, 21, which were also synthesized for this study. Incorporation of rigid peripheral tetrahydropyrazino ring systems in the pentacyclic azines 13, 14, and 15 are responsible for the improved fluorescence and singlet oxygen quantum yields relative to the tricyclic azines 20 and 21.