bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of thiopyrano[2,3‐d] pyrimidines and thieno[2,3‐d]pyrimidines
Authors: Santilli Arthur A. , Scotese Anthony C. 
Published: April 2009

AbstractThe reaction of 4‐chloro‐5‐cyano‐2‐methylthiopyrimidine (I) with ethyl mercaptosuccinate (II) in refluxing ethanol containing sodium carbonate has afforded diethyl 3‐amino‐2‐(methyl‐thio)‐7H‐thiopyrano[2,3‐d]pyrimidine‐6,7‐dicarboxylate (IV). Displacement of the methylthio group in IV with hydrazine gave the corresponding hydrazino derivative which underwent Schiff base formation with benzaldehyde or 2,6‐dichlorobenzaldehyde. Treatment of IV in refluxing acetic anhydride afforded the corresponding diacetylated amino derivative. Partial saponification of IV with sodium hydroxide gave 5‐amino‐2‐(methylthio)‐7H‐thiopyrano‐[2,3‐d]pyrimidine 6,7‐dicarboxylic acid 6 ethyl ester (VIII). The reaction of 4‐amino‐6‐chloro‐5‐cyano‐2‐phenylpyrirnidine (XI) with II resulted in the formation of ethyl 4‐amino‐6‐(ethoxy‐carbonyl)‐5,6‐dihydro‐5‐amino‐2‐phenylthieno[2,3‐d]pyrimidine‐6‐acetate (XIII) which when subjected to hydrolysis gave ethyl 4,5‐diamino‐2‐phenylthieno[2,3‐d]pyrimidine‐6‐acetate isolated as the hydrochloride (XIV). Diazotization of IV with sodium nitrite in acetic acid unexpectedly afforded diethyl 5‐(acetyloxy)‐6,7‐dihydro‐6‐hydroxy‐2‐(methylthio)‐5H‐thio‐pyrano[2,3‐d]pyrimidine‐6,7‐diearboxylate (XV). Several structural ambiguities were resolved by ir and pmr spectra.
Synthéses de bitriazoles‐3(‐5),1′ méthylés en position 1 ou 4 et de bitriazoles‐4,4′
Authors: Aouial Mohamed , Bernardini Antoine , Viallefont Philippe 
Published: April 2009

AbstractDeux synthéses de bitriazoles caractérisé's par une jonution C3(5)‐N1′ ou N4‐N4′ sont rapportées et discutées. Elles font appel aux réactions de substitution nucléophile de I'halogene des halogénotriazoles par l'anion du triazole lui‐měme et aux réactions de désulfuration de bis‐s‐triazolothiadiazines par le Nickel Raney. La détermination de leur structure est prouvée par RMN. Les spectres UV de ces dérives sont aussi rapportés.
Tosylation of 2‐(monosubstituted)amino‐1,3,4‐thiadiazoles
Authors: L'abbé Gerrit , Verhelst Gabriel , Huybrechts Lucas , Toppet Suzanne 
Published: April 2009

AbstractTosylation of 2‐benzylamino‐ and 2‐anilino‐5‐phenyl‐1,3,4‐thiadiazoles (1a,b) in the presence of triethylamine affords the ring‐sulfonylated products 2a,b which isomerize in a later stage of the reaction to the exocyclic amino‐sulfonylated products 3a,b. Acetylation of 1a,b gives the acylamino substituted thiadiazoles 4a,b directly as the only reaction products. The 13C nmr data are discussed and their importance for the study of prototropic tautomerism and for structure elucidation of the reaction products is indicated.
A noteworthy improvement of the 3‐diazo‐4‐oxo‐3,4‐dihydroquinoline photosynthesis of indole‐3‐carboxamides
Authors: Carlock John T. , Bradshaw Jerald S. , Stanovnik Branko , Tišler Miha 
Published: April 2009

AbstractThe use of benzene, in place of methylene chloride as solvent, allows the synthesis of amides of indole‐3‐carboxylic acid via the photolysis of 3‐diazo‐4‐oxo‐3,4‐dihydroquinoline to occur in significantly higher yield and requiring shorter reaction times. This modification makes unnecessary the time consuming and costly chromatographic purification step, and allows the synthesis of novel amides which could not he isolated using the previous method.
Benzo[f]isoindole analogs II. Thieno[3,4‐b]quinoxaline
Authors: Roland Mitchel M. , Anderson Richard C. 
Published: April 2009

AbstractThe transient existence of thieno[3,4‐b]quinoxaline (2d) as a product of dehydration of 1,3‐dihydrothieno[3,4‐b]quinoxaline 2‐oxide (5) was demonstrated by trapping experiments with N‐phenylmaleimide and dimethyl acetylenedicarboxylate. Attempts to isolate 2d from reaction mixtures arising from dehydration of 5 and from dehydrogenation of 1,3‐dihydro‐thieno[3,4‐b]quinoxaline (8) were unsuccessful.
The stereochemical course of the catalytic hydrogenation of 3(2H)isoquinolinones
Authors: Deak G. , Hazai L. , Tóth G. 
Published: April 2009

Abstract4‐Benzylidene‐1‐phenyl‐1,4‐dihydro‐3(2H)isoquinolinone (2), 4‐benzyl‐1‐phenyl‐3(2H)isoquino‐linone (3) and 4‐benzyl‐3‐ethoxy‐1‐phenylisoquinoline (6) have been hydrogenated on palladium‐charcoal catalyst. The structure of the products and the ratio of the stereoisomers have been determined by nmr spectroscopy and by LIS measurements with Eu(dpm)3.
Preparation and reactions of some 1,2,3,4‐Tetrahydro‐2,3‐disubstituted 7(or 8)hydroxy‐1,4‐dioxopyrazino[1,2‐a] indoles
Authors: Saxena Mahendra P. , Ahmed Skakti R. 
Published: April 2009

Abstract1,2,3,4‐Tetrahydro‐2,3‐disubstituted 7(or 8) hydroxy‐1,4‐dioxopyrazino[1,2‐a]indoles have been prepared by the condensation of 6(or 5)benzyloxyindole‐2‐carbonyl chloride with d1‐N‐ alkylamino acid ethyl esters in the presence of triethyl amine followed by the hydrogenolysis over palladium‐carbon. Methylation and alkaline hydrolysis of 1,2,3,4‐tetrahydro‐2‐benzy1‐1,4‐dioxopyrazino[1,2‐a]indole are discussed.
Isothiazoles IX. Halogenation of 2‐substituted‐4‐isothiazolin‐3‐ones
Authors: Weiler Ernest D. , Petigara Ramesh B. , Wolfersberger Martha H. , Miller George A. 
Published: April 2009

AbstractBromination of 4‐isothiazolin‐3‐ones, I, gave the 4‐bromo derivatives, III, in good yields, while formation of 4,5‐dibromo derivatives, IV, was much more difficult. In contrast, chlorination of I, even under mild conditions, gave primarily 4,5‐dichloro derivatives, VI, and lesser amounts of the 4‐chloro derivatives, V. Vigorous bromination of the 4‐methyl analog of I gave the 5‐bromo derivatives, VIII, whereas mild chlorination gave predominantly the 4,5,5‐trichloro derivatives, X.
Substituted pyrimidines. II. 1,3‐Dimethylisocytosine and related compounds
Authors: Maehr Hubert , Smallheer Joanne , Toome Voldemar 
Published: April 2009

Abstract1,3‐Dimethyl‐1,2‐dihydro‐2‐imino‐4(3H)pyrimidinone (1,3‐dimethylisocytosine) was prepared by methylation of 2‐amino‐3‐methyl‐4(3H)pyrimidinone and was degraded in alkaline solution to a mixture of 3‐methyl‐2‐methylamino‐4(3H)pyrimidinone, 1,3‐dimethyl‐2,4‐(1H,3H)pyrimid‐indione, 2‐methylamino‐l‐methyl‐4(1H)pyrimidinone, 1‐methyl‐2,4‐(1H,3H)pyrimidindione and 3‐methyl‐2,4‐(1H,3H)pyrimidindione. Thiation of the title compound gave both 1,2‐dihydro‐1,3‐dimethyl‐2‐thio‐4(3H)pyrimidinone and 1,3‐dimethyl‐2,4‐(1H,3H)pyrimidinedithione. The title compound is a tautomerically fixed pyrimidine and its uv spectra were compared with related compounds, notably 3‐methyl‐2‐dimethylarnino‐4(3H)pyrimidinone which is also tautomerically fixed.
Heterocycles from ketenimines XI. Oxindoles
Authors: Barker Marvin W. , Sung Hsiu‐Sun 
Published: April 2009

AbstractThe reaction of ketenimines with heterocyclic N‐oxides yields N‐substituted oxindoles. Hydrolysis of these adducts or acid work‐up of the original reaction mixtures leads directly to oxindoles in which the nitrogen atom is unsubstituted.
1,2,4‐Triazoles from formic acid‐Induced rearrangement of 6‐(Phenylhydrazino)uracils
Authors: Wright G. E. 
Published: April 2009

AbstractThe structure of a rearrangement product of 6‐(phenylhydrazino)uracil + formic acid has been proved to be 1‐phenyl‐3‐carboxamidomethyl‐1,2,4‐triazole: hydrolysis of this compound and thermal decarboxylation of the intermediate acid gave the known 1‐phenyl‐3‐methyl‐1,2,4‐triazole. Yields of triazoles from substituted 6‐(phenylhydrazino)uracils follow inversely yields of pyrimidoindoles derived from Fischer‐type cyclization [J. Heterocyclic Chem., 13, 539 (1976)]. The lack of formation of a triazole from 3‐methyl‐6‐(phenylhydrazino)uracil suggests that an intermediate in this rearrangement, ie., that resulting from formylation of the anilino nitrogen atom followed by intramolecular cyclization involving the uracil 1‐nitrogen atom, must undergo conjugate elimination of water to generate the triazole ring.
A new route to the phosphindole system
Authors: Holah David G. , Hughes Alan N. , Kleemola Daniel 
Published: April 2009

AbstractA new and possibly general route to the hitherto relatively inaccessible simple substituted phosphindoles, utilizing the extreme readiness of simple phosphole sulfides to undergo Diels‐Alder dimerization, is described. The synthesis reported here is that of 3,6‐dimethyl‐l‐phenylphosphin‐dole sulfide which is prepared in good yield in two simple steps from the readily available 3‐methyl‐l‐phenylphosphole.
Oxidative reactions of polyarylpyrroles. II. Oxidative dimerization with dichromate
Authors: Sprio Vincenzo , Petruso Salvatore , Ceraulo Leopoldo , Lamartina Liliana 
Published: April 2009

AbstractThe behaviour of 2,4,5‐triphenylpyrrole and 2‐(p‐tolyl)‐4,5‐diphenylpyrrole under oxidation conditions with dichromate has been investigated. The several reaction products obtained were separated by column cliromatography. In addition to products previously obtained using other oxidizing agents (2), additional products were isolated, namely, the 2,3′‐dimers IIIa.b and related oxygenated products Va,b and VIa,b. Their structures were assigned by means of elemental analyses, chemical behaviour and spectroscopic data (ir, uv, nmr andms).
Chlorosulfonation of 2‐arylimidazoles
Authors: Baldwin J. J. , Lumma P. K. , Ponticello G. S. , Novello F. C. , Sprague J. M. 
Published: April 2009

AbstractThe chlorosulfonation of 2‐arylimidazoles was investigated; the resulting sulfonyl chloride derivatives were isolated and characterized as the corresponding sulfonamides. When the 2‐aryl substituent was 3,4‐dichlorophenyl or 3‐pyridyl, chlorosulfonation occurred only on the imidazole ring. The chlorosulfonation of 2‐(4‐chlorophenyl)imidazole was temperature dependent, yielding either a mono or disulfonamide after treatment with ammonia. The structure of this disulfon‐amide was determined from pmr spectra to be 2‐(4‐chloro‐3‐sulfamoyl)‐4(5)sulfamoylimidazole.
Photosensitized cyclodimerizations of 4‐vinylpyridine, 2‐vinylpyridine, and 2‐vinylquinoline
Authors: Nakano Tatsuhiko , Martín A. , Rivas C. , Pérez C. 
Published: April 2009

AbstractIrradiations of 4‐vinylpyridine and of 2‐vinylpyridine in either f‐butyl alcohol or benzene, with benzophenone, yielded a single photodimer, which, on the basis of the nmr and mass spectral data, was assigned the trans‐head‐to‐head structure (I). Upon irradiation in either t‐butyl alcohol or benzene, in the presence of benzophenone, 2‐vinylquinoline gave a single photodimer whose structure and stereochemistry were also determined from the nmr and mass spectral evidence as (V). Irradiation of 2‐vinylquinoline in benzene, in the absence of benzophenone, also gave rise to the same photodimer, but, when t‐butyl alcohol or methanol was used as a solvent, no dimer formation was observed.
Intramolecular 1,3‐cycloadditions of nitrile ylides bearing an acetylenic function
Authors: Garanti Luisa , Padova Giovanna , Zecchi Gaetano 
Published: April 2009

AbstractTreatment of amides 1a,b with thionyl chloride followed by reaction with triethylamine gave 1,4‐dihydro[1]benzopyrano[4,3‐b]pyrrole derivatives (4a,b) arising from intramolecular 1,3‐cycloaddition of intermediate nitrile ylides (3a,b).
The novel one step syntheses of benzobis‐ and benzotris[1,2,5]thiadiazole
Authors: Mataka Shuntaro , Takahashi Kazufumi , Tashiro Masashi 
Published: April 2009

AbstractThe reaction of tetrasulfur tetranitride with alkoxybenzenes such as anisole (1a), o‐ (1b), m‐(1c), p‐dimethoxybenzenes (1d), and benzyl ether (1e) was investigated. Benzo[1,2‐c:3,4‐c′ :5,6‐c ]‐tris[1,2,5]thiadiazole (2) and benzo[1,2, c:3,4‐c′ ]bis[1,2,5]thiadiazoles (3a and 3b) were isolated. J. Chem. Soc., 14, 963 (1977)
Synthesis of 4H‐furo[3,2‐b]indole derivatives A new heterocyclic ring system
Authors: Tanaka Akira , Yakushijin Kenichi , Yoshina Shigetaka 
Published: April 2009

Abstract4H‐Furo[3,2‐b]indole (III) was prepared from deoxygenation of 2‐(2‐nitrophenyl)furan (II) with triethyl phosphite and thermolysis of 2‐(2‐azidophenyl)furan (VI). 4H‐ or 4‐alkylfuro [3,2‐b]indole‐2‐carboxaldehydes (VIII, IXa‐c) were obtained by Vilsmeier formylation of the corresponding furo[3,2‐b]indoles (III, VIIa‐c). 4H‐Furo[3,2‐b]indole‐2‐carboxaldehyde (VIII) was submitted to the Cannizzaro, Wittig and reduction reactions. The Shiff's bases were obtained by the reaction of 4‐ethylfuro[3,2‐b]indole‐2‐carboxaldehyde (IXb) with amines. J. Heterocyclic Chem., 14, 975 (1977)
Synthesis of 5‐amino‐2,3‐dihydro‐1H‐1,4‐benzodiazepines
Authors: Corral Carlos , Madroñero Ramón , Vega Salvador 
Published: April 2009

AbstractA number of 5‐amino‐2,3‐dihydro‐lH‐1,4‐benzodiazepines (II) have been prepared from the reaction of 5‐methylmercapto‐2,3‐dihydro‐1H‐1,4‐benzodiazepine (I) with amines. Another alternate approach based on the cyclodehydration of the ureic compounds (IV) was unsuccessful. The synthesis of I was accomplished by methylation of the 1,2,3,4‐tetrahydro‐5H‐5‐thioxo‐1,4‐benzodiazepine (VI) with dimethyl sulfate in methanol‐dioxane. Another attempted method for the synthesis of I is also presented. J. Heterocyclic Chem., 14, 985 (1977)
1,3‐Oxazolidin‐4‐ones. Synthesis and configuration of cis and trans isomers
Authors: Pilgram Kurt , Pollard Glenn E. 
Published: April 2009

AbstractMixtures of cis and trans 1,3‐oxazolidin‐4‐ones were obtained by cyclodehydration, in the presence of p‐toluenesulfonic acid or boron trifluoride etherate, of lactamide and N‐methyl‐lactamide with aromatic and aliphatic aldehydes. The products were separated by column (silica) chromatography and their configurations were determined.
4(And 5)‐cyclopropylamino‐5(and 4)halo‐3(2H)pyridazinones. Formation and characterization of isomers
Authors: Pilgram Kurt H. , Pollard Glenn E. 
Published: April 2009

AbstractThe reactions of 4,5‐dihalo‐3(2H)pyridazinones with ammonia and amines gave mixtures of 5‐amino‐4‐halo‐ and 4‐amino‐5‐halo‐3(2H)pyridazinones separated by chromatography. Structures were elucidated by means of retention values (Rf) and confirmed by independent synthesis.
Aqueous synthesis of a new 1,3,2‐diazaphospholidine
Authors: Schenkenberg Philip R. , Williams Charles R. 
Published: April 2009

AbstractN,N,N'‐Trimethylphosphoric triamide reacts with aqueous glyoxal to produce a 1,3,2‐diaza‐phospholidine 5‐membered ring system (III) in good yield. The ease of this synthesis belies the results with other phosphoramides where no cyclic species could be isolated.
Intramolecular substitution of unactivated aryl groups by thioamide anion
Authors: Spitulnik M. J. 
Published: April 2009

AbstractThe general reaction of intramolecular nucleophilic substitution of unactivated aryl groups by thioamide anion in dipolar aprotic amide solvent is extended by the syntheses of 6‐chloro‐5‐methoxy‐2‐methylbenzothiazole from 2′,4′‐dichloro‐5′‐methoxythioacetanilide and 6‐methoxy‐2‐methylbenzothiazole from 4′‐methoxy‐2′‐nitrothioacetanilide. The six‐membered fused ring heterocycles, 2‐methyl‐4H,3‐benzothiazine and 6,8‐dichloro‐3‐rnethyl‐1H‐4,1,2‐benzothiadi‐azine are also prepared.
Formation of a pyrazopyrazolone by the pyrolysis of antipyrine diazonium fluoroborate
Authors: Robbins Philip J. 
Published: April 2009

AbstractThe pyrolysis of antipyrine 4‐dizaonium fluoroborate gave an antipyrylazopyrazopyrazolone instead of the desired 4‐fluoroantipyrine. This compound was formed by intermolecular and intramolecular coupling of the diazo compound at elevated temperatures. J. Heterocyclic Chem., 14, 1107 (1977)
Some derivatives of 1,8‐naphthyridine, 1,2‐dihydropyrindo[2,3‐B][1,8]‐naphtyridine and 2H‐pyrano[2,3‐b][1,8]naphtyridine
Authors: Henery Ronald A. , Hammond Peter R. 
Published: April 2009

AbstractThe pyrolysis of antipyrine 4dizaonium flouroborate gave an antipyrylazopyrazopyrazolone instead of the desired 4‐fluoroantipyrine. This compound was formed by intermolecular and intramolecular coupling of the diazo compound at elevated temperatures.
Nucleosides. CIX. 2′‐Deoxy‐ψ‐isocytidine, 2 ‐deoxy‐ψ‐uridine, and 2′‐deoxy‐l‐methyl‐ψ‐uridine. Isosteres of deoxycytidine, deoxyuridine and thymidine
Authors: Chu C. K. , Reichman U. , Watanabe K. A. , Fox J. J. 
Published: April 2009

Abstract2′‐Deoxy‐ψ‐isocytidine (VIIβ), a 2′‐deoxy analog of antileukemic ψ‐isocytidine and also a C‐nucleoside analog of deoxycytidine, was synthesized from ψ‐uridine by making use of the newly discovered pyrimidine to pyrimidine transformation reaction [J. Chem. Soc., 14, 537 (1977)]. 2′‐Deoxy‐ψ‐uridine (IIβ) and 2′‐deoxy‐l‐methyl‐ψ‐uridine (V), both C‐nucleoside analogs of deoxyuridine and thymidine, were also synthesized.ψ‐Uridine was converted into the 2′‐chloro analogs (I) which was reduced with tributyltin hydride to give an α,β‐mixture of 2′‐deoxy‐ψ‐uridines. The β‐isomer (11β was trimethylsilylated and the product (III) treated with methyl iodide to afford the 1‐methyl derivative (IV). After hydrolytic removal of the trimethylsilyl groups from IV, the thymidine analog (V) was obtained in good yield.A crude mixture of II was converted in good yield into an α,β‐mixture of 1,3‐dimethyl‐2 ‐deoxy‐ψ‐uridines (VI) by treatment with DMF dimethyl acetal in DMF. Treatment of the β‐isomer (VIβ) with guanidine, however, gave the α,β‐mixture of 2 ‐deoxy‐ψ‐isocytidines (VII). The pure β‐isomer (VIIβ) was obtained by thick layer chromatography. The pure α‐isomer (VIIα) was obtained when VIα was treated with guanidine.2 ‐Deoxy‐ψ‐isocytidine (VIIβ) and 2 ‐deoxy‐l‐methyl‐ψ‐uridine (V) exhibited inhibitory activity against P815 cells (ID5 0 1.2 μg./ml. and 4.9 μg./ml., respectively) and the thymidine analog V was found to be active against Streptococcus faecium var. duran. J. Heterocyclic Chem., 14, 1119 (1977)
Nucleophilic displacement of aromatic fluorine. Part V. Use of nitrogen heterocycles as nucleophiles
Authors: Gilman Norman W. , Holland Betty C. , Walsh Gregory R. , Fryer R. Ian 
Published: April 2009

AbstractThe scope of the nucleophilic displacement of aromatic halogens on 1,4‐benzodiazepine precursors by the anions of pyrroles, pyrazoles and imidazoles was studied both with and without electron‐withdrawing substitutents on the heterocyclic nucleophiles. Some of the products proved to be useful intermediates for the synthesis of novel fused 1,4‐benzodiazepines.
Cycloadditions dipolaires‐1,3 II. Addition des diarylnitrilimines au N‐methyl‐indole. Etude expérimentale et essai d'interprétation
Authors: Laude Bernard , Soufiaoui Mohamed , Arriau Et Jean 
Published: April 2009

AbstractOn étudie la réactivite du N‐méthylindole vis‐à‐vis de plusieurs diarylnitrilimines. Les cycloadduits obtenus sont des dérivés du méthyl‐8 dihydro‐3a,8a pyrazolo [3,4‐b] indole. La structure proposée est en accord avec les données analytiques et spectrales. Elle est confirmée par voie chimique. Une interprétation fondee sur la méthode de perturbation au second ordre des propriétés des orbitales frontières rend compte de la régiospécificité observée.
Synthesis and antimalarial effects of [1]benzothieno[3,2‐f]quinazoline‐1,3‐diamine
Authors: Johnson Judith , Elslager Edward F. , Werbel Leslie M. 
Published: April 2009

AbstractBromination of 2‐dibenzothiophenamine has been shown to afford 1‐bromo‐2‐dibenzothio‐phenamine rather than the previously reported 3‐isomer. This material was converted to the 1‐cyano derivative and cyclized with chloroformamidine hydrochloride to [l]benzothieno‐[3,2‐f]quinazoline‐1,3‐diamine. Both this and the corresponding 7,7‐dioxide were devoid of antimalarial activity.
Reactivity of 2‐amino‐1,3,4‐thiadiazoles. Nucleophilic behaviour of some 2‐amino‐1,3,4‐thiadiazoles: Model compounds
Authors: Werber Giuseppe , Buccheri Francesco , Gentile Manlio 
Published: April 2009

AbstractThe ambident nucleophilic behaviour of some 2‐amino‐5‐H‐1,3,4‐thiadiazoles in alkylation, acylation and nitrosation reaction has been verified. The structures assigned to the 2‐amino‐1,3,4‐thiadiazoles (1a‐i) and to the Δ2‐1,3,4‐thiadiazolines (2a‐e) agree with the spectral data.
Synthesis of imidazo[4,5‐d]pyridazine nucleosides related to inosine
Authors: Dan Cook P. , Dea Phoebe , Robins Roland K. 
Published: April 2009

AbstractSeveral imidazo[4,5‐d]pyridazine nucleosides which are structurally similar to inosine were synthesized. Anhydrous stannic chloride‐catalyzed condensation of persilylated imidazo[4,5‐d]‐pyridazin‐4(5H)one (1) and imidazo[4,5‐d]pyridazine‐4,7(5H,6H)dione (16) with 1‐O‐acetyl‐2,3,5‐tri‐O‐benzoyl‐β‐D‐ribofuranose (3) provided (after sodium methoxide deblocking) 6‐β‐D‐ribo furanosylimidazo[4,5‐d]pyridazin‐4(5H)one (5) and 3,6‐di‐(β‐D‐ribofuranosyI)imidazo[4,5‐d]pyridazin‐4‐one (7); and 1‐(β‐D‐ribofuranosyl)imidazo[4,5‐d]pyridazine‐4,7(5H,6H)dione (19) and 1,5 or 6‐di‐(β‐D‐ribofuranosyl)imidazo[4,5‐d ]pyridazine‐4,7(5H or 6H)dione (21), respeeitvely. 4,7‐Diehloro‐1‐β‐D‐ribofuranosylimidazo[4,5‐d]pyridazine (12) and dimethyl 1‐β‐D‐ribofuranosylimidazole‐4,5‐dicarboxylate (26), both prepared from stannic chloride‐catalyzed ribosylations of the corresponding heterocycles, were converted in several steps to 3‐β‐D‐ribo‐furanosy limidazo[4,5‐d]pyridazin‐4(5H)one (14) and nucleosidc 19, respectively. Acid‐catalyzed isopropylidenation of mesomeric betaine 7 or nuclcoside 14 provided 3‐(2,3‐isopropylidene‐β‐D‐ribofuranosyl)imidazo[4,5‐d]pyrizin‐4(5H)one (31). 1‐β‐D‐Ribofuranosylimidazo[4,5‐d]‐pyridazine (29) was obtained in several steps from nueleoside 12. The structure of the nucleosides was established by the use of carbon‐13 and proton nmr.
Investigations of substituted benzofuran‐3‐carboxylates, benzo[1,2‐b:4,5‐b']difurans and benzo[1,2‐b:4,3‐b']difurans
Authors: McPherson H. L. , Ponder B. W. 
Published: April 2009

AbstractThe Michael addition of ethyl acetoacetate to benzoquinone, toluquinone, and chlorobenzo‐quinone leads to formation of substituted 5‐hydroxybenzofuran‐3‐earboxylates and linear benzo‐[1,2‐b:4,5‐b']difurans. The previously reported structural proof for the benzodifurans obtained from chlorobenzoquinone and toluquinone, although correct in the conclusion, is shown to be invalid. Proof of the linear benzodifuran structures was obtained by comparison of the uv spectra with authentic angular benzo[1,2‐b:4,3‐b']difurans.
Synthesis of heterocyclic compounds VIII. 4H‐Pyrans from α‐benzoylcinnamonitriles
Authors: Quinteiro M. , Seoane C. , Soto J. L. 
Published: April 2009

AbstractA new synthesis of substituted 4H‐pyrans is reported. The base catalyzed reaction of substituted α‐benzoy]cinnamonitri]es (I) with malononitrile yields 6‐amino‐2,4‐diaryl‐3,5‐dieyano‐4H‐pyrans (III). Similarly, 6‐amirio‐2,4‐diaryl‐5‐carbethoxy‐3‐cyano‐4H‐pyrans (IV) have been prepared Irom ethyl cyanoacetate.
Carbon‐13 magnetic resonance spectra of cocaine metabolites and derivatives
Authors: Baker John K. , Borne Ronald F. 
Published: April 2009

AbstractThe carbon‐13 nmr spectral assignments oi cocaine, O‐benzoylecgonine, ecgonine, norcocaine, O‐benzylnorecgonine, norecgonine, and N‐allylnorcocaine were made. The assignments were primarily based on the correlation of substituent effects within series and selective proton irradiation studies.
Reaction of ketenes with N,N‐disubstituted α‐aminomethyleneketones VII. Synthesis of 2H,5H‐[1]benzothiopyrano[4,3‐b]pyran and 2H,5H‐thiopyrano[4,3‐b]pyran derivatives
Authors: Mosli Luisa , Menozzi Giulia , Schenone Pietro 
Published: April 2009

AbstractThe dipolar 1,4‐cycloaddition of dichloroketerie to N,N‐disubslituled 3‐aminomethylene‐2,3‐dihydro‐4‐thiochromanones and 3‐aminomethylenetelrahydro‐4‐thiopyranones gave N,N‐disubstituted 4‐amino‐3,3‐diehloro‐3,4‐dihydro‐2H,5H‐[1]benzolhiopyrano[4,3‐b]pyran‐2‐ones and 4‐amino‐3,3‐dichloro‐3,4,7,8‐tetrahydro‐2H,5H‐thiopyrano[4,3‐b]pyran‐2‐ones, respectively, only in the ease of aromatic or strong hindering aliphatic N‐substitution. The adducts gave N,N′‐disubstituted 4‐amino‐3‐chloro‐2H,5H‐[1]benzothiopyrano[4,3‐b]pyran‐2‐ones and 4‐amino‐3‐chloro‐7,8‐dihydro‐2H,5H‐thiopyrano[4,3‐b]pyran‐2‐ones, respectively, by dehydro‐chlorination with DBN. By chromatography on neutral alumina, 3‐(2,2‐dichloroethylidene)‐2,3‐dihydro‐4‐thiochromanone was isolated as an unstable liquid from the reaction between dichloroketerie and 3‐diethylaminornethylene‐2,3‐dihydro‐4‐thiochromanone.