bluuebunny/crossref_metadata_2025_split huggingface dataset:
Condensed thiophenes from sulfur bridging. II. Catalyzed reaction of azabiaryls with hydrogen sulfide
Authors: Klemm L. H. , Mccoy D. R. , Klopfenstein C. E. 
Published: March 2009

AbstractSulfur bridging inlo the phenylpyridines, 2‐ and 3‐phenylquinolines, and the symmetric bi‐pyridines was effected by means of hydrogen sulfide and an alumina catalyst at 630° to give [1]benzothienopyridines, [1]benzothienoquinolines, and thienodipyridines, respectively. Structures of products were assigned on the bases of spectral and chromatographic studies, as well as of separate syntheses. Relative yields of the various products are rationalized in terms of a model for interaction between a chemisorbed sulfur atom and the substrate molecule.
Thieno[2,3‐d]pyrimidines. I. A new method for the preparation of esters and amides of thieno[2,3‐d] pyrimidine‐6‐carboxylic acids
Authors: Santilli Arthur A. , Kim Dong Han , Wanser Stephen V. 
Published: March 2009

AbstractA novel method for the preparation of esters and amides of thieno[2,3‐d]pyrimidine‐6‐carb‐oxylic acids was described. A typical example was the direct formation of ethyl 5‐amino‐2‐methylthiothieno[2,3‐d]pyrimidine‐6‐earboxylate(IIIa) from 4‐chloro‐2‐methylthio‐5‐pyrimidine‐carbonitrile (Ia) and ethyl mercaptoacetate in refluxing ethanol containing sodium carbonate. Displacement of the methylthio group in IIIa by various amines gave the corresponding amino derivatives. The reactions of IIIa and related compounds with acetylating agents such as acetic anhydride or chloroacetyl chloride gave various products. Treatment of 5‐carbethoxy‐4‐chloro‐2‐phenylpyrimidine(IV) with methyl mercaptoacetate afforded the dechloro intermediate diester Va, which cyclized on reaction with sodium ethoxide to form methyl 5‐hydroxy‐2‐phenylthieno‐[2,3‐d]pyrimidine‐6‐carboxylate (Vla). The synthesis was expanded to include the preparation of various new 2,4,5‐trisubstituted thieno[2,3‐d]pyrimidine‐6‐carboxylic acid esters and amides (Charts I‐V).
Novel polycyclic heterocycles. VII. Synthesis of tetracyclic ketones and derivatives from tricyclic 5,11‐dihydrodibenz[b,e][1,4] oxazepines
Authors: Petigara Ramesh B. , Yale Harry L. 
Published: March 2009

AbstractMichael addition of 5,11‐dihydrodibenz[b,e][1,4]oxazepines to acrylonitrile gave 5,11‐di‐hydrodibenz[b,e][1,4]oxazepine‐5‐propionitriles, which were converted to the corresponding methyl 5‐propionates. Mild alkaline hydrolysis of these esters furnished the key intermediates, the 5,11‐dihydrodibenz[b,e] [1,4]oxazepine‐5‐propionic acids. In the preferred procedure, these propionic acids were cyclized to the tetracyclic ketones in yields of 60‐90%, by the action of one equivalent of trifluoroacetic anhydride in benzene. When ring C was involved in cylcization, 1,2‐dihydro‐3H,7H‐quino[8,1‐cd][1,5]benzoxazepin‐3‐ones were obtained, and when ring A was involved, 1,2‐dihydro‐3H,8H‐quino[1,8‐ab] [4,1]benzoxazepin‐3‐ones were formed. With 1c, both modes of cyclization were observed. In an alternative procedure that gave lower yields, the propionic acids were first converted to the corresponding acid chlorides, and these were cyclized by means of anhydrous stannic chloride; as anticipated, the products by this method were identical with those obtained via the trifluoroacetic anhydride method. Several reactions of these tetra‐cylcic ketones, e.g., their ease of oxime formation, and dehydrogenation to the α,β‐unsaturated ketones, are described. The α,β‐unsaturated ketones do not form oximes.The structures assigned to the ketones are based on interpretations of their pmr, uv, and ir spectra. These assignments were confirmed by an X‐ray analysis of a single crystal of one representative ketone, 2b; the X‐ray study was also useful in indicating the thermodynamically preferred conformation of 2b. The structures of all the other compounds followed from similar spectral interpretations. The mass spectra of a few compounds are also discussed.
Bicyclic bases Ambident anions as intramolecular nucleophiles in the formation of 2‐oxa‐5‐azabicyclo[2.2.1] heptane derivatives
Authors: Porloghese P. S. , Sepp D. T. 
Published: March 2009

AbstractThe intramolecular cyclization of the ambident anion 5 derived from condensation of N, O‐ditosylhydroxy‐L‐proline acid chloride with dimethyl malonate anion was studied under a variety of reaction conditions. Cyclization occurred solely by O‐alkylation to give 2‐oxa‐5‐azabicyclo[2.2.1 ]heptanes. The NMR speetra of the hicyclo compounds are diseussed.
Thiophene series. XV The effect of leaving groups on the reactivity of nitro‐activated thiophene derivatives with sodium thiophenoxide
Authors: Guanti Giuseppe , Dell'Erba Carlo , Macera Paola 
Published: March 2009

AbstractThe effect of leaving groups on the reactivity of 3‐X‐2‐nitrothiophene (1), 2‐X‐3‐nitrothiophene (II) and 2‐X‐5‐nitrothiophene (III) (X = Cl, Br, I, OC6H4NO2(p), SO2C6 H5) with sodium thiophenoxide has been examined.The results show that the reactivity ratio kIII/kII is always greater than unity and is relatively uninfluenced by changing leaving groups compared to the ratio kI/kII. The ratio kI/kII is greater or smaller than unity, according to following patterns of leaving groups

Examination of the reactivity of the three series of compounds having Cl, Br, I and C6H4NO2(p) as leaving groups showed the absence of an “element effect” which indicates that in the transition states of these displacement reactions there is little breaking of the bond to the group being displaced.
Studies on the syntheses of azole derivatives. Part VIII. Photolysis of N‐aryl‐N‐benzylearbamoyl azides [studies on the syntheses of heterocyclic compounds. Part CDXV
Authors: Kametani Tetsuji , Shio Masahisa 
Published: March 2009

AbstractPhotolysis of N‐benzyl‐N‐phenylearbamoylazide (IVc) afforded 1‐benzy 1‐2‐benzimidazolinone (Ic), 2‐benzimidazolinone (IIe), 4‐benzy 1‐2‐benzimidazolinone (IIe), and 5‐benzy1‐2‐benzimidazo‐linone (IIf)‐ The same reaction of N‐benzyl‐N‐(4‐chlorophenyl) carbamoyl azide (IVd) gave 3‐benzyl‐1‐(phenylhydrazocarbonyl)‐2‐benzimidazolinone (VIb) besides the above four products. In the case of N‐benzyl‐4‐(4‐butoxyphenyl)carbamoyl azide (IVe), 1‐benzy1‐5‐butoxy‐2‐benz‐imidazolinone (1e), 5‐butoxy‐2‐benzimidazolinone (IId), 5‐benzy1‐2‐benzimidazolinone (IIf), and 4‐benzy1‐6‐butoxy‐2‐benzimidazolinone (IIg).
Isothiazoles I: 4‐isothiazolin‐3‐ones. A general synthesis from 3,3′‐dithiodipropionamides
Authors: Lewis Sheldon N. , Miller George A. , Hausman Martin , Szamborski Eugene C. 
Published: March 2009

AbstractThe syntheses of 3‐hydroxyisothiazole, 4‐methyl‐3‐hydroxyisothiazole, and a eomprehensive series of the respective 2‐substituted‐4‐isothiazoIin‐3‐ones have been achieved by the one‐step chlorination‐cyclization of the corresponding 3,3 ‐dithiodipropionamides. In several instances, 5‐chloro‐4‐isothiazolin‐3‐ones were isolated as side products; however, no 4‐chloro‐4‐isothiazo‐lin‐3‐ones were evident in the reaction mixtures. These observations, coupled with the exclusive 4‐ or 4,5‐halogenation of several preformed 4‐isothiazoIin‐3‐ones, support a proposed reaction pathway involving introduction of chlorine α to the sulfur atom in intermediate reaction products.
1,3,5‐Trisubstituted hexahy drotriazines as mannich reagents. I. Preparation of secondary aminomethyl sulfide hydrochlorides
Authors: Reynolds Delbert D. , Cossar Bernard C. 
Published: March 2009

Abstract1,3,5‐Trisubstituted hexahy drotriazines react with hydrogen chloride in the presence of anhydrous solvents to form useful intermediates for the introduction of the RNHCH2‐ group into compounds which undergo the Mannich reaction. The effectiveness of the new aminomethyl‐ating agent has been demonstrated by the preparation of secondary aminomethyl sulfide hydro‐chlorides.
1,3,5‐Trisubstituted hexahydrotriazines as mannich reagents. III. Preparation and cleavage of 3,4‐dihydro‐6‐hydroxy‐3‐substituted‐2H‐1,3‐benzoxazine hydrochlorides
Authors: Reynolds Delbert D. , Cossar Bernard C. 
Published: March 2009

Abstract3,4‐Dihydro‐6‐hydroxy‐3‐substituted‐2H‐1,3‐benzoxazine hydrochlorides have been prepared by the reaction of hydroquinones with novel aminomethylating reagents prepared from 1,3,5‐trisubstituted hexahydrotriazines. With these monooxazine hydrochlorides is formed an equal molar amount of an amine hydrochloride. Purification leads to low yields. This difficulty has been circumvented by the use of bis(alkoxymethyl)amines in the presence of anhydrous hydrogen chlorides. The monooxazines have been hydrolyzed to yield ortho‐secondary aminomethylhydro‐quinone derivatives.
Mass spectral fragmentation patterns of various 6‐substituted 2,4‐bis‐(m‐aminoanilino)‐s‐triazines
Authors: Karliner J. , Seltzer R. 
Published: March 2009

AbstractThe mass spectra of 6‐substituted‐2,4‐bis‐(m‐aminoanilino)‐s‐triazines were determined and found to be dominated by intense molecular ions (base peak), strong M‐H peaks and fragment ions diagnostic for the arylamino and C‐6 substituents. Mechanisms have been proposed for the formation of the major peaks in the spectra. Fragmentation pathways involving hydrogen transfer reactions have been rationalized by concomitant opening of the triazine ring rather than an amino‐imino tautornerization as previously suggested. Fragmentation reactions accompanied by rearrangement modes have also been encountered in some of the compounds studied.
Pyrrolopyrimidine nucleosides VII. A study on electrophilic and nucleophilic substitution at position six of certain pyrrolo[2,3‐d] pyrimidine nucleosides
Authors: Tolman Richard L. , Robins Roland K. , Townsend Leroy B. 
Published: March 2009

AbstractA study involving the reactivity of the pyrrolo[2,3‐d] pyrimidine ring system at position 6 with another exocyclic group (CN or magnified image‐NH2) already residing at C5 has established that hydrogen and bromine are susceptible to electrophilic and acid‐catalyzed nucleophilic substitution, respect‐tively. In one instance a strong nucleophile (hydrazine) gave nucleophilic substitution at position 6 which was followed by a reaction with the o‐nitrile group to afford the tricyclic nucleoside 4,5‐diamino‐8‐(β‐D‐ribofuranosyl)pyrazolo[3′, 4′ :5,4] pyrrolo[2,3‐d] pyrimidine (4).
Synthesis and properties of some aryl‐s‐triazines
Authors: Gillespie J. S. , Acharya Satya Prakash , Davis R. E. 
Published: March 2009

AbstractThe synthesis and reactions of several substituted s‐triazines were studied in attempts to prepare 4,6‐bis(4‐chlorophenyl)‐s‐lriazine‐2‐carboxylie acid (2) and 2‐aldehyde (8). The 4,6‐bis‐(4‐chlorophenyl)‐s‐triazine derivatives were surprisingly inert to a variety of reagents. 4,6‐Bis‐(4‐chlorophenyl)‐2‐methyl‐s‐triazine (1) could not be oxidized with any of a variety of oxidants. On bromination 1 gave 4,6‐bis(4‐chlorophenyl)‐2‐dibromomethyl‐s‐triazine (4) which was resistant to hydrolysis but on oxidation with selenium dioxide gave 2. Compound 2 was also prepared by the oxidation of 4,6‐bis(4‐chlorophenyl)‐2‐hydroxymethyl‐s‐triazme (7) with potassium permanganate. Other reagents did not oxidize 7 to 8. 4,6‐Bis(4‐chloroanilino)‐2‐mcthyl‐s‐triazine (3) was also resistant to oxidizing agents. 2‐Diazomethy1‐4,6‐dichloro‐s‐triazine (11) on reaction with 4‐chloroaniline gave 4,6‐bis(4‐chloroanilino)‐2‐chloromethyl‐s‐triazine (12). All efforts to prepare 8 were unsuccessful.
Mcsoionic purinone analogs. I. Initial theoretical considerations
Authors: Coburn R. A. 
Published: March 2009

AbstractThirty mesoionic analogs of purin‐6‐one, ‐2‐one and ‐2,6‐dione have been formulated based upon reported simple monocyclie mesoionic systems and factors influencing their stability. lluckel molecular orbital calculations were performed for these structures employing the ω, ω′ ‐technique and the variation of resonance integrals with bond orders. The results provide predictions concerning the properties and stability of the analogs, assist the determination of reasonable synthetic goals, and serve as input for more sophisticated theoretical treatments.
Preparation of indoles from 4H‐3,1‐benzothiazines by extrusion of sulfur
Authors: Lednicer Daniel , Emmert D. Edward 
Published: March 2009

AbstractProlonged heating of a series of α ‐hydroxy‐α‐aryl‐o‐toluidines in the presence of base and carbon disulfide afforded the corresponding 4H‐3,]‐benzothiazine‐2‐thiones. Treatment of the thiolalkyl ethers of these compounds with strong bases led to ring contraction to the corresponding 2‐thioalkyl indole with concommitant extrusion of sulfur. The scope of the reaction was examined.
The synthesis of 1,3,4,5‐tetrahydro‐2,3‐benzoxazepines and 1,2,4,5‐tetrahydro‐3,2‐benzoxazepines
Authors: Pifferi G. , Consonni P. , Monguzzi R. , Omodei‐Salé A. 
Published: March 2009

AbstractCondensation of o‐bromomethylphenethyl bromide with potassium salt of N‐hydroxyurethan afforded 3‐earbethoxy‐1,3,4,5‐tetrahydro‐2,3‐benzoxazepine, which was hydrolyzed to 1,3,4,5‐tetrahydro‐2,3‐benxoxazepine (III). The reaction of o‐aeetoxymethylphenethyl bromide (VIb) with potassium salt of N‐hydroxyurethan in DMF, gave a complex mixture, from which O‐[2‐(o‐acetoxymethylphenyl)(ethyl]‐N‐earbethoxyhydroxylamine (VIIa) was separated. Subsequent desacetylation to VIIb and halogenation yielded O‐[2‐(o‐bromomethylphenyl)ethyl]‐N‐carbethoxyhydroxylamine (VIIc). By treatment of VIIc with potassium hydroxide, 2‐carbethoxy‐1,2,4,5‐tetrahydro‐3,2‐benzoxazepine (X) was obtained together with small amounts of 6,15‐diearbethoxy‐5,6,8,9,14,15,17, 18‐octahy drodibe nzo[d,I]‐1,8‐dioxa‐2,9‐diazaeyclotetradec in e (XI). Hydrolysis of X with potassium hydroxide gave 1,2,4,5‐tetrahydro‐3,2‐benzoxazepine (XII).N‐Alkyl and N‐acyl derivatives of III and XII were also prepared.
Reactions of 4‐pyrones with primary amines. A new class of ionic associates
Authors: Van Allan J. A. , Reynolds G. A. , Alessi J. T. , Chang S. Chie , Joines R. C. 
Published: March 2009

AbstractPrimary aliphatic amines react with 2,6‐dimethyl‐4‐pyrone to give 2,6‐dialkylamino‐2,5‐heptadien‐4‐one derivatives. When the alkyl group was methyl, the diamino derivative cyclized on warming to give 1,2,6‐trimethyl‐4‐pyridone. The corresponding butylamino derivative did not thermally cyclize, but did give a pyridone on treatment with acid. The isopropylaminoketone did not cyclize. Several examples of 1,2,6‐trisubstituted‐4‐pyridones formed “ionic associates” consisting of two parts of the pyridone and one part of perchloric acid. These associates are useful primary standards for nonaqueous titrations.
Chemistry of thienopyridines. XII. Selective formation of N‐oxides, sulfoxides, and sulfones in some tricyclic systems
Authors: Klemm L. H. , Mathur S. B. , Zell Reinhard , Merrill R. E. 
Published: March 2009

AbstractDirect conversion of [1]benzothieno[3,2‐b]pyridine (IVa), thieno[3,2‐b:4,5‐b']dipyridine (Va), and thieno[2,3‐b:4,5‐b']dipyridine (VIa) into their sulfoxides was effected by means of an equimolar quantity of iodobenzene dichloride in aqueous acetonitrile. Treatment of IVa‐VIa with excess chlorine gas in carbon tetrachloride and then with water gave the corresponding sulfones, IVc‐VIc. Hydrogen peroxide in glacial acetic acid converted Va and VIa into di‐N‐oxides, thieno[3,2‐b]pyridine into its N‐oxide, and sulfone VIc into an N‐oxide sulfone (X). Spectral and chemical means of distinguishing amongst the oxide functions are noted, and rationalizations for selectivity in the oxidations are discussed.
The reaction of trivalent phosphorus nucleophiles with phenyl azidoformate and 5‐aryloxy‐1,2,3,4‐thiatriazoles
Authors: Pilgram Kurt , Görgen Franz , Pollard Clenn 
Published: March 2009

AbstractBenzoyl azide and phenyl azidoformate react with phosphorous triamides (8) to give isolable phosphazides (11 and 12) which decompose thermally to give the corresponding acylated iminophosphoranes (13 and 14). With 5‐aryloxy],2,3,4‐thiatriazoles (15) and 8, 1:1 reaction products are formed which are best represented by the 2,2‐dihydro‐1,3,4,5,2‐thiatriazaphosphorine (23) structure. This structure assignment is based on thermal degradation studies and on the interpretation of infrared data of the 1:1 adducts; their mass spectra show fragmentation patterns in accordance with their formulation.
Conformalional analysis of azetidines‐evidenee for a non‐planar ring
Authors: Higgins Robert H. , Cromwell Norman H. , Paudler William W. 
Published: March 2009

AbstractThe proton coupling constants and particularly chemical shifts of a series of 1‐alkylazetidines, 1‐alkylazeudin‐3‐ols, 1‐alkyl‐3‐methylazetidin‐3‐ols, and C‐methylazetidines are rationalized in terms of a conformationally mobile, non‐planar azetidine ring. Preferred conformations for these compounds are discussed.
Bieyclic bases . Synthesis and stereochemical studies of chiral 5‐substituted N‐tosyl‐2‐azabicyclo[2.2.1[ heptanes
Authors: Portoghese P. S. , Lattin D. L. , Telang V. G. 
Published: March 2009

AbstractThe synthesis of chiral exo and endo 5‐sulbstituted N‐losyl‐2‐azabicyclo[2.2.1]heptanes is reported. The nearly identical exo‐endo equilibrium ratios of the title compounds and the carbocyclic analogs suggest that their geometries and sterie interactions are quite similar.
Cyclic phosphonium ylides
Authors: Davies Maureen , Hughes A. N. 
Published: March 2009

AbstractSynthetic approaches to cyclic phosphonium ylides are reviewed and the syntheses are classified according to reaction type rather than ring size. Particular attention is paid to syntheses leading to isolable or easily characterizable cyclic ylides and a number of other reactions in which cyclic phosphonium ylides are postulated as transient intermediates are discussed. There is also a brief discussion regarding structure and bonding in certain of the more stable cyclic ylides such as the 1,1‐disubslituted phosphorins and certain diphosph(V)orins.
The reduction and hydrolysis of some 7,7‐diethylpyrazolo[1,2‐a]‐pyridazine‐6,8(7H)dione derivatives
Authors: Gillis Bernard T. , Izydore Robert A. 
Published: March 2009

AbstractThe chemistry of several of the Diels‐Alder adducts formed by the reaction of 4,4‐diethylpyrazoline‐3,5‐dione (1) with conjugated dienes was studied with respect to reduction (hydride and catalytic) and reaction with base. Reaction of the 2,3‐dimethyl‐1,3‐butadiene adduct with lithium aluminum hydride followed by hydrogenation gave 1,3,5,6,7,8‐hexahydro‐cis‐endo‐6,7‐dimethyl‐2,2‐diethylpyrazolo[1,2‐a]pyridazine (11). Attempted conversion of this compound to 3,3‐diethyl‐cis‐7,8‐dimethyl‐1,5‐diazacyclononane (12) gave instead a compound which has been tentatively identified as N‐(2,3‐dimethyl‐4‐aminobutyl)‐2‐ethyl‐2‐methylbutanaldimine (14). Lithium aluminum hydride reduction of 4,4‐diethylpyrazolidine‐3,5‐dione (22) or the adducts formed from 1 and cyclopentadiene or 1,3‐cyclohexadiene gave good yields of 4,4‐diethylpyrazolidine (21). This later reduction gave a new and efficient synthetic route to the pyrazolidine ring system. Lithium aluminum hydride reduction of 5,6,7,8‐tetrahydro‐5,8‐ethano‐2,2‐diethylpyrazolo[1,2‐a]pyridazine‐1,3(2H)dione (26) followed by hydrogenolysis led to a high yield of 4,4‐diethyl‐2,6‐diazabicyclo[5.2.2]undecane (28) which is the first reported example of this ring system. Reaction of several of the adducts with ethanolic potassium hydroxide resulted in the opening of the five‐membered ring.
Studies on the syntheses of heterocyclic compounds. part CDLV. The mass spectral investigation and synthesis of the ochotensinan skeleton
Authors: Kametani T. , Hibino S. , Shibuya S. , Takano S. 
Published: March 2009

AbstractSyntheses of several 1‐spiroisoquinoline derivatives (VIII, IX, X, XI, XII, XIII, and XIV) were carried out and their unique mass spectral fragmentations were reported. The presence of carbonyl groups at the C‐9 and C‐14 positions caused cleavage of the five membered ring through the elimination of one or two carbon monoxide groups. This led to the formation of the three membered ring system on the fragmentation pathway.
The synthesis of 1,4‐diazacycl[3,2,2]azine
Authors: Paudler William W. , Vandahm Richard A. , Park Young N. 
Published: March 2009

AbstractThe diazaanalog of “cycl[3,2,2]azine”, “1,4‐diazacycl[3,2,2]azine” (1,4,7b‐triazacyclopent‐[cd]indene) and its 2‐methyl derivative were prepared. These compounds are subject to facile acid‐catalyzed hydrolysis affording substituted imidazo[1,2‐a]pyridines.
5‐Azapurines and the structures of sym‐triazole intermediates
Authors: Hirata Tadashi , Twanmoh Li‐Ming , Wood Harry B. , Goldin Abraham , Driscoll John S. 
Published: March 2009

AbstractSeveral isomers are possible when an isocyanate or an isothiocyanate is allowed to react with 3‐amino‐1,2,4‐triazole. It was found that variations in reagents or reaction conditions could be used to produce isomeric derivatives. The effect of substituents on the chemical shifts of adjacent ring protons is described for a number of new triazole derivatives. These data can be used to assign structures to new sym‐triazole reaction products. Appropriate triazoles were used as intermediates in the synthesis of s‐triazolo[1,5‐a]‐s‐triazine (5‐azapurine) derivatives. Spectral properties, methods of synthesis, and modes of degradation are described for several new members of this ring system.
The crystal and molecular structure of 1,1,2,4,4,5‐hexaphenyl‐1,4‐diphosphoniacyclohexadiene‐2,5 dibromide
Authors: Brown J. N. , Trefonas L. M. 
Published: March 2009

AbstractThe crystal and molecular structure of 1,1,2,4,4,5‐hexaphenyl‐1,4‐diphosphoniacyclohexadiene‐2,5 dibromide has been determined by a single crystal, x‐ray diffraction study using diffractometer data. The compound crystallizes in the space group P21/c with unit cell constants a = 8.813(1), b = 36.736(4), c = 12.478(1) Å, and β = 120.91°(1). The structure was solved by the heavy atom method and refined by block‐diagonal least‐squares to a final R = 0.04 for the 2761 statistically significant reflections. The structure determination shows that the central phosphonium ring is a diene and not a delocalized structure as anticipated. The ring is in the boat conformation with the axial phenyl rings aligned essentially parallel to each other and 3.55 Å apart.
Model photostable compounds
Authors: Otterstedt Jan‐Erik Anders , Pater Richard 
Published: March 2009

AbstractThe photostabilities and syntheses of 2,2′‐bis(o‐hydroxyphenyl)‐5,5′‐bipyrimidine, 6,6′‐bis(o‐hydroxyphenyl)‐3,3′‐bipyridine and 3,8‐bis(o‐hydroxyphenyl)‐4,7‐phenanthroline are discussed. The syntheses of parent compounds lacking the o‐hydroxy groups are also described.
6H‐indeno[1,2‐b]pyrido[3,2‐e]pyrazines. A new heterocyclic ring system
Authors: Israel Mervyn , Jones Lynne C. , Modest Edward J. 
Published: March 2009

AbstractCondensation of 1,2‐indanedione and 1,2,3‐indanetrione hydrate (ninhydrin) with 2,3‐diamino‐pyridines gave a number of compounds belonging to the hitherto unknown 6H‐indeno[1,2‐b]‐pyrido[3,2‐e]pyrazine ring system. The unsymmetrical nature of the reactants can theoretically result in isomeric ring closure products. Assignment of the 6H‐ ring system was based upon the identity of 6H‐indeno[1,2‐b]pyrido[3,2‐e]pyrazin‐6‐one obtained from 2,3‐diaminopyridine and ninhydrin with material prepared by unequivocal synthesis. The direction of cyclization of ninhydrin and 1,2‐indanedione with the diamines was shown to be the same by reduction of the indenopyridopyrazinones to the corresponding indenopyridopyrazines. Some physical, chemical, and tumor growth‐inhibitory properties of the products are reported.
Chemistry of thienopyridines. XIII. Selective formation of sulfones in Bi‐ and tricyclic Systems. Thieno[2,3‐b]pyridine 1,1‐dioxide as a dienophile
Authors: Klemm L. H. , Merrill R. E. 
Published: March 2009

AbstractBicyclic and tricyclic thienopyridines are converted into sulfones in 13‐73% yield by means of acid‐hypochlorite. The sulfone thieno[2,3‐b]pyridine 1,1‐oxide (Ib) undergoes Diels‐Alder condensation with furan (both exo and endo products formed), anthracene, and naphthacene. Self‐condensation of Ib occurs with elimination of sulfur dioxide to give 8‐(3‐pyridyl)quinoline (XV). The structure of XV was established by means of pmr and a europium shift reagent. Ultraviolet, pmr, and mass spectral data for various compounds are presented and discussed.