bluuebunny/crossref_metadata_2025 huggingface dataset:
The preparation of 2,6‐diaminopyrazine, 2,6‐diazidopyrazine and some of their derivatives
Authors: Shaw John T. , Brotherton Christine E. , Moon Robert W. , Winland Mark D. , Anderson Mark D. , Kyler Keith S.
Published: March 2009

A much improved synthesis of the heretofore difficultly obtainable 2,6‐diaminopyrazine (4) was afforded by the low‐pressure catalytic hydrogenation (palladium on carbon) of 2,6‐diazido‐pyrazine (2); reaction of 2,6‐dichloropyrazine (1) and sodium azide gave 2 in 84% yield. The outcome of the reduction was found to be solvent dependent: 1,2‐dimethoxyethane containing aqueous ammonia gave 4 in 83% yield; 1,2‐dimethoxyethane alone gave 5‐aminotetrazolo[1,5‐a]‐pyrazine (3) in 26% yield. Additional alternative syntheses of 3 and 4 are described. A number of acyl and azo derivatives of 4 were prepared. Reactions of 2 with dimethyl acetylenedicarboxylate and ethyl acetate (base catalyzed) leading to vic‐triazole derivatives are also described.
The addition of hydroxylamine to the halogenated uracils
Authors: Priest John H. , Scheffler Julie E. , Sander Eugene G.
Published: March 2009

Hydroxylamine adds reversibly to C‐6 of uracil bases via a multistep mechanism. Equilibrium constants measured at several pH values, 25°, μ = 3.0 M are: uracil, 0.25 M−1; 5‐iodouracil, 0.30 M−1, 5‐bromouracil, 0.24 M−1, 5‐chlorouracil, 0.06 M−1 and 5‐fluorouracil, 5.11 M−1. The kinetics of hydroxylamine addition to both 5‐bromo‐and 5‐iodouracil are complex. At low hydroxylamine buffer concentrations, the rate constants are second‐order with respect to hydroxylamine buffer but at higher concentration a first‐order dependence is approached. Hydroxylamine elimination from 5‐iodo‐6‐hydroxylamino‐5,6‐dihydrouracil is subject to general base catalysis by tris(hydroxy‐methyl)aminomethane but at higher concentrations the rate constants are not proportional to the concentration of general base. This reaction is subject to solvent effects where increasing ethanol concentration depresses the rate when measured at constant pH. These kinetics can be rationalized in terms of a multistep reaction pathway in which hydroxylamine addition to C‐6 of the halogenated uracil precedes general acid catalyzed proton transfer to C‐5 yielding the final 6‐hydroxylaminodihydropyrimidine product.
Dioxo‐2,5 pipérazines. 1. La synthèse des carboxythiazolo dioxo‐2,5 pipérazines
Authors: Jerumanis Stanislas , Lemieux Alain
Published: March 2009

Line route nouvelle et générale pour préparer les carboxythiazolo dioxo‐2,5 pipérazines est decrite. Dansles reactions de formation du cycle de la dioxo‐2,5 pipérazine, la Néthoxycarbonyle éthoxy‐2 dihydro‐1,2 quinoléine (EEDQ) a été utilisée comme agent d'activation. Par cette méthode le butoxycarbonyl‐9 diméthyl‐7,7 dioxo‐2,5 thia‐8 diaza‐1,4 bicyclo[4,3,0]nonane (6) et le car‐boxy‐9 dimèthyl‐8,8 dioxo‐2,5 thia‐7 diaza‐1,4 bicyclo[4,3,0]nonane (8)ont été obtenus, avec un rendement quasi quantitatif, en utilisant la carboxy‐4 butoxycarbonyl‐2 diméthyl‐5,5 thiazolidine (4) comme produit de départ. L'ester 6 a été hydrolysé avec de l'hydroxyde de barium en acide correspondant 7 et l'acide 8 traité avec du diazométhane a donné l'ester 9. L'ester 6 a été synthé‐tisé aussi à partir de l'ester éthylique de la N‐(butoxycarbonyl‐2 carboxy‐4 diméthyl‐5,5 thiazoli‐dine)glycine (10). Les données spectroscopiques sont interprétées pour confirmer les structures de nouveaux produits obtenus.
The synthesis of 11H‐1,2,4‐triazolo[4,3‐b]pyridazino[4,5‐b]indoles,11H‐tetrazolo[4,5‐b]pyridazino[4,5‐b]indoles and 1,2,4‐triazolo[3,4‐f]‐1,2,4‐triazino[4,5‐a]indoles
Authors: Monge Vega A. , Aldana I. , Rabbani M. M. , Fernandez‐Alvarez E.
Published: March 2009

This paper describes the synthesis of the previously unknown 11H‐1,2,4‐triazolo[4,3‐b]pyridazino[4,5‐b]indoles (2) and 11H‐tetrazolo[4,5‐b]pyridazino[4,5‐b]indoles (3) from 4‐hydrazino‐5H‐pyridazino[4,5‐b]indoles (1), as well as the synthesis of 1,2,4‐triazolo[3,4‐f]‐1,2,4‐triazino‐[4,5‐a]indoles (10) from 2‐indolecarbohydrazide (4). Compounds 2 were obtained by acylation of compounds 1, followed of thermal cyclization and compounds 3 by treating compounds 1 with nitrous acid. The reactions of compound 4 with formic acid or ethyl orthoformiate gave 1,2‐dihydro‐1‐oxo‐1,2,4‐triazino[4,5‐a]indole (6). Treating this last compound with phosphorus oxychloride or phosphorus pentasulfide, followed by hydrazine, gave 1‐hydrazino‐1,2,4‐triazino‐[4,5‐a]indole (9). Acylation of this last compound, followed of cyclization gave compounds 10. All the compounds were characterized by elemental analysis and ir and 1H‐nmr spectra.
Studies on sulphur heterocycles. Reactions of 6,7‐dihydrobenzo[b]thiophen‐4(5H)one derivatives and their conversion to 7‐substituted thieno[2,3‐h][1]benzopyran‐8‐ones
Authors: Asprou Chris M. , Brunskill John S. A. , Jeffrey Howard , De Asish
Published: March 2009

Cyclization of γ‐(2‐thienyl)butryic acid with acid anhydrides gives 2‐acyl derivatives as well as the expected 6,7‐dihydrobenzo[b]thiophen‐4(5H)one. Several reactions of these ketones have been studied including their conversion to 0,0‐diethyl thiophosphonohydrazones. 7‐Substituted thieno[2,3‐h][1]benzopyran‐8‐ones have been prepared via 4‐hydroxybenzo[b]thiophen‐5‐carbaldehydes.
New heterocyclic ring systems from α‐hydroxymethyleneketones. X Thiadiazasteroid‐related compounds
Authors: Brunelli Carlo , Fravolini Arnaldo , Grandolini Giuliano , Cristina Tiralti M.
Published: March 2009

Some thiadiazasteroid analogues have been synthesized by the reaction of 3‐hydroxymethyl‐enebenzo[h]thiochroman‐4‐one with hydrazine and substituted hydrazines, semicarbazide and thiosemicarbazide. Pmr data supporting the structural assignments have been discussed.
On the reaction of methoxide ion with bromoiodothiophenes
Authors: Gronowitz Salo , Hallberg Anders , Glennow Christer
Published: March 2009

The reaction of 3‐bromo‐2‐iodothiophene with sodium methoxide in methanol, pyridine or hexamethylphosphoric triamide and the same reaction of 4‐bromo‐2‐iodo‐ and 4‐bromo‐3‐iodo‐thiophene in pyridine led to a halogen‐dance, giving the same mixture of 3‐bromothiophene, bromo‐iodothiophenes, diiodo‐bromothiophenes and triiodo‐bromothiophenes. The reaction of all three isomeric bromo‐iodothiophenes with sodium methoxide in methanol in the presence of cupric oxide gave 4‐bromo‐2‐methoxythiophene.
Hydrolytic cleavages of 7‐nitro‐2‐phenyl‐1,2‐benzisoxazol‐3‐one. Evidence for the occurrence of a benzidine‐like rearrangement of N,O‐diphenylhydroxylamines
Authors: Sheradsky Tuvia , Avramovici‐Grisaru Schely
Published: March 2009

Preparation of the title compound 1 is described. Its treatment with base caused hydrolysis of the amide bond and subsequent benzidine‐like rearrangement to give 4′‐amino‐3‐carboxy‐4‐hydroxy‐5‐nitrobiphenyl (4). Acid treatment caused cleavage of the nitrogen‐oxygen bond and rearrangement to 7‐nitro‐3‐phenylbenzoxazol‐2‐one (6).
Sels d'aziridinium stables C‐fonctionnalisés III: Synthèse et caractérisation d'aziridines protonées épimères à l'azote
Authors: Baret Par Paul , Rivoirard Eve‐Marie , Pierre Jean‐Louis
Published: March 2009

Le traitement d'aziridines C‐fonctionnalisées par l'acide fluorosulfurique permet la préparation des sels d'aziridinium N‐protonés correspondants avec des rendements élevés. L'action du fluorosulfate de méthyle sur les aziridines secondaires conduit également aux sels d'aziridinium N‐protonés. Les sels protonés sont isolés et caractérisés par voies chimique et spectroscopique. La configuration des épimères à l'azote est établie par effet Overhauser nucléaire et la stéreéchimie de la réaction est discutée.
Syntheses of fluorescent dyes. IX. New 4‐hydroxycoumarins, 4‐hydroxy‐2‐quinolones, 2H,5H‐Pyrano[3,2‐c]benzopyran‐2,5‐diones and 2H,5H‐Pyrano[3,2‐c]quinoline‐2,5‐diones
Authors: Knierzinger Andreas , Wolfbeis Otto S.
Published: March 2009

7‐Substituted 4‐hydroxycoumarins (2a‐e) and 4‐hydroxy‐2‐quinolones (2f‐i) have been synthesized from the appropriate phenols or anilines and were converted to the enamines 3 using triethoxymethane and aniline. Condensation of 3 with nitriles 4a‐h gave substituted 2H,5H‐pyrano[3,2‐c]benzopyran‐2,5‐diones (5a‐r) or 2H,5H‐pyrano[3,2‐c]quinoline‐2,5‐diones (5s‐x), which exhibit both spontaneous and stimulated fluorescence with maxima between 418 and 549 nm. The marked influence of an electron withdrawing 3‐substituent in 5 is demonstrated by the fluorescence spectra of 7a,b (synthesized from 2d,e and ethyl 3‐oxobutyrate), whose maxima are sharply shifted to the blue as compared with compounds 21‐r.
A reinvestigation of the stevens rearrangement of 1,3,4‐trimethyl‐1‐(3,4,5‐trimethoxybenzyl)‐1,2,5,6‐tetrahydropyridinium chloride
Authors: Bosch J. , Domingo A. , Lopez F. , Rubiralta M.
Published: March 2009

1,3,3‐Trimethyl‐2‐(3,4,5‐trimethoxyphenyl)‐4‐methylenepiperidine (XI) is prepared in an unambiguous way which involves the Refortmatsky reaction followed by ethanolysis on the N‐(3,4,5‐trimethoxybenzylidene)methylamine, later treatment of the resulting aminoester with ethyl acrylate, ring closure by Dieckmann reaction with decarbalkoxylation and, finally, a Wittig reaction on the piperidone obtained. The resulting methylenepiperidine XI differs in its physical and spectroscopic data from the methylene derivative IIIa obtained by the Stevens rearrangement of the 1,3,4‐trimethyl‐1‐(3,4,5‐trimethoxybenzyl)‐1,2,5,6‐tetrahydropyridinium chloride, whose structure must be reviewed.
Nouvelle synthèse des pyrido[4,3‐b]quinoléines substituées sur leur sommet 1
Authors: Rivalle Christian , Bisagni Emile
Published: March 2009

On décrit une nouvelle synthèse de pyrido[4,3‐b]quinoléines diversement substituées sur leur sommet 1 qui comporte seulement trois étapes. Ainsi, les hydroxy‐2 arylamino‐4 pyridines sont transformées dans les conditions de la réaction de Vilsmeir‐Haack en donnant directement les oxo‐1 dihydro‐1,2 pyrido[4,3‐b]quinoléines; la chloration de ces dernières engendre ensuite les chloro‐1 pyrido[4,3‐b]quinoléines qui sont aisément substituées par des amines variées.
A new procedure for the cyclization of 2‐indole‐ and 3‐indolecarbohydrazones to 5H‐pyridazino[4,5‐b]indole derivatives
Authors: Vega A. Monge , Palop J. A. , Martínez M. T. , Alvarez E. Fernández
Published: March 2009

A new procedure for the cyclization of 2‐indolecarbohydrazones (5) to 1,2,3,4‐tetrahydro‐4‐oxo‐5H‐pyridazino[4,5‐b]indoles (6) and for the cyclization of 3‐indolecarbohydrazones (7) to 1‐oxo‐1,2,3,4‐tetrahydro‐5H‐pyridazino[4,5‐b]indoles (8 and 9) is described. The hydrazones (5 or 7) were treated with an acyl halide (acetyl or benzoyl chlorides) and triethylamine in ethyl acetate of chloroform as solvents to give the compounds 6 (20–70%) from the compounds 5, and the compounds 8 (20–60%) from the compounds 7. Through refluxing with ethanol‐hydrochloric acid the compounds 8a‐8f selectively separate the acetyl group on N5 to give the respective compounds, 9a‐9f. The ir and 1H‐nmr spectra of all the compounds 5, 6, 7, 8 and 9 and the uv, mass and 13C‐nmr spectra of the compounds 7h, 7i, 8h and 8i are discussed.
v‐triazolines. Part XIV . 1‐aryl‐5‐dialkylaminomethyl‐4‐methylene‐4,5‐dihydro‐v‐triazoles
Authors: Pocar Donato , Rossi Luisa Maria , Trimarco Pasqualina
Published: March 2009

The cycloaddition of arylazides to 1‐methyl‐ and 1‐benzyl‐2,5‐dihydropyrrole affords pyrrolo[3,4‐d]‐v‐triazole derivatives which react with methyl iodide, yielding the corresponding quaternary ammonium salts. On base‐catalyzed elimination 1‐aryl‐5‐dialkyl‐aminomethyl‐4‐methylene‐4,5‐dihydro‐v‐triazoles are formed. Their structure and behaviour toward methoxide and secondary amines are discussed.
A synthesis of hydrothiopyran‐3‐ones. The intramolecular cyclization of allylthiopropionyl and propargylthioacetyl chlorides
Authors: Ichikawa Kazuo , Inoue Seiichi , Sato Kikumasa
Published: March 2009

Intramolecular cyclization of 2‐(allylthio)propionyl chloride (3a) effected by aluminum chloride gave two dihydrothiopyran‐3‐ones (5a,6a) and 5‐chloro‐2‐methyltetrahydrothiopyran‐3‐one (7a). Treatment of propargylthioacetyl chloride (4a) with aluminum chloride afforded 5‐chloro‐3,6‐dihydro‐2H‐thiopyran‐3‐one (10a). The cyclization reactions of related compounds were also studied.
The oxidation of a series of phthalyl alcohols
Authors: Bhattacharjee Debkumar , Popp Frank D.
Published: March 2009

A series of phthalyl alcohols containing methoxy and methyl substituents were prepared by lithium aluminum hydride reduction of phthalides. Oxidation of the phthalyl alcohols with activated manganese dioxide or with barium manganate gave phthalaldehydes or phthalides depending on the position of the ring substituents.
Conformations privilegiees de dithieno[c,e]dihydro azepines, oxepinnes et thiepinnes: Etude par spectroscopie d'absorption electronique
Authors: Meunier P. , Arriau J.
Published: March 2009

L'étude comparative des spectres d'absorption électronique (uv) de dithiéno[c,e]dihydro “épinnes” et des bithiophènes correspondants permet de conclure à 1′existence privilégiée en solution d'une forme “croisée” pour les composés cycliques étudies. Cette conclusion est confirmee, d'une part par 1′analyse des résultats théoriques (CNDO/S) et, d'autre part, par l'étude de dérives stériquement encombrés.
Sur diverses possibilités de formation de pyrimidines à partir de formyl‐3 chromone
Authors: Pene Cécile , Hubert‐Habart Michel
Published: March 2009

La guanidine transforme: la formyl‐3 chromone en un mélange d'amino‐2 (hydroxy‐2 benzoyl)‐5 pyrimidine et d'amino‐2 hydroxy‐5 5H(1) benzopyranno[4–3‐d]pyrimidine; le diacétate de méthylidyne‐3 chromone en amino‐2 hydroxy‐5 5H(1) benzopyranno[4,3‐d]pyrimidine, et l'ox‐ime de la formyl‐3 chromone en amino‐2 5H(1)benzopyranno[4,3‐d]pyrimidinone‐5. La thiourée, l'acetamidine et la nitroguanidine sont également capables d'engendrer des pyrimidines du měme type avec la formyl‐3 chromone, le diacétate de méthylidyne‐3 chromone ou la (dioxolanne‐1,3 yl‐2)‐3 chromone.
O‐carbamoyl oximes as potential analgesics
Authors: Evenson Gerald N. , Moffett Robert Bruce
Published: March 2009

Preparation of oxadiazinones 2, from α‐anilinoacetophenone oximes and O‐carbamoyl‐2,3‐dihydro‐4‐quinolinone oximes 3, from quinolinones are described.
Studies on chemotherapeutics I. Synthesis of 5‐substituted‐4‐oxo‐1,4‐dihydro‐3‐pyridinecarboxylic acid derivatives
Authors: Balogh MÁRia , Hermecz István , Mészaros Zoltán , Simon KÁLman , Pusztay Levente , Horváth GÁBor , Dvortsak Peter
Published: March 2009

Ethyl 5‐substituted‐4‐oxo‐1,4‐dihydro‐3‐pyridinecarboxylates were synthetized by reacting 1,3,5‐triazine with 4‐substituted ethyl acetoacetate derivatives in ethanol, in the presence of sodium ethoxide. The l‐alkyl‐5‐substituted‐4‐oxo‐1,4‐dihydro‐3‐pyridinecarboxylic acids required for the antimicrobial studies were prepared by N‐alkylation (with triethyl phosphate or alkyl halides) and alkaline hydrolysis of the pyridone esters.
2,3,5,6‐tetramethylmorpholine. V. Mechanism study of cyclization of 3,3′‐iminobis‐2‐butanols
Authors: Hernestam Sven , Stenvall Gillis
Published: March 2009

The mechanism of cyclization of 3,3′‐iminobis‐2‐butanols to 2,3,5,6‐tetramethylmorpholines in sulfuric acid is studied. Contrary to our prior suggestions, the ring closure seems to be exclusively a normal S‐type substitution. The partial inversion before the cyclization is discussed.
Reaction between 2,2′ ‐dithiodianiline and acetylenic ketones or esters. A new synthesis of 4H‐1,4‐benzothiazines
Authors: Liso Gaetano , Trapani Giuseppe , Berardi Vincenza , Marchini Paolo
Published: March 2009

The title compounds (3a‐c) together with the benzothiazolines (4b‐c) were obtained by reaction between 2,2′ ‐dithiodianiline (1) and acetylenic ketone (2a) or esters (2b‐c). A possible pathway involving the formation and subsequent cyclization to 3 of enamine intermediates A and/or B, is suggested.
The synthesis of some 4‐nitroisothiazoles as potential antifungal agents
Authors: Albert Anthony H. , O'Brien Darrell E. , Robins Roland K.
Published: March 2009

5‐Chloro‐3‐methyl‐4‐nitroisothiazole (III) was prepared by nitration of 5‐chloro‐3‐methyliso‐thiazole. Compound III was found to exhibit significant antifungal activity in vitro against a wide spectrum of fungi. The synthesis of 3‐methyl‐4‐nitro‐5‐nitroamino, 5‐carboxamido, 5‐N,N‐dimethylamino and 5‐β‐hydroxyethylaminoisothiazole are here reported. The synthesis of 3‐methyl‐4‐nitroso‐5‐ethylthioisothiazole (IX) is reported via an unusual reaction of 5‐bromo‐3‐methyl‐4‐nitroisothiazole (I) and sodium ethyl mercaptide. 5‐Bromo‐4‐nitroisothiazole was prepared by nitration of 5‐bromoisothiazole. The nitro group was shown to be essential for antifungal activity.
A novel ring transformation of uracil into the benzene ring system
Authors: Hirota Kosaku , Kitade Yukio , Senda Shigeo
Published: March 2009

Reaction of 5‐formyl‐1,3‐dimethyluracil with some active methylene compounds in the presence of base causes novel ring transformations to give the p‐hydroxybenzoates and the nicotinate.
Benzolactams. II. Synthesis of tetrahydrobenz[d]indeno‐[1,2‐b]azepines and their 12‐Oxo derivatives
Authors: Orito Kazuhiko , Kaga Harumi , Itoh Mitsuomi , De Silva S. Osmund , Manske Richard H. , Rodrigo Russel
Published: March 2009

Aromatic methoxy and/or methylenedioxy substituted 7‐methyltetrahydrobenz[d]indeno[1,2‐b]‐azepines 7 and their 12‐oxo derivatives 8 were efficiently synthesized by the general method consisting of two types of intramolecular dehydrative cyclizations, as follows. N‐Methyl‐N‐β‐phenethylacetamides 1 were cyanomethylated in the two‐step process of chloromethylation and treatment of the resultant benzyl chlorides with sodium cyanide. The condensation of the benzyl cyanides 2 with the appropriate benzaldehydes, followed by reduction of the benzylidene function, gave α,β‐diphenylpropionitriles 3. Successively, hydrolysis to the amino acids 4 and the thermal cyclization converted 3 to the benzylbenzazepinones 5, which were also prepared by benzylation of the benzazepinones 6 smoothly by heating of 5 with phosphoryl chloride to afford the title azepines 7. Further, these tetracyclic enamines 7 underwent autoxidation to the corresponding 12‐oxo derivatives 8, on exposure to oxygen in the presence of Triton B.
Synthesis of 2‐and 6‐chloro‐3‐(5‐methyl‐1,3,4‐oxadiazol‐2‐yl)pyridines
Authors: Ponticello Gerald S. , Engelhardt Edward L. , Baldwin John J.
Published: March 2009

A convenient synthesis of 2‐ and 6‐chloro‐3‐(5‐methyl‐1,3,4‐oxadiazol‐2‐yl)pyridines, 3 and 10, utilizing the readily available amide 7 is described. Incorporation of the 3‐t‐butylamino‐2‐hydroxypropoxy side chain onto 3 provided 2, a potential bioisostere of 1. The antihypertensive activities of 2 and 12 were evaluated in the spontaneously hypertensive rat model.
Synthesis of 1,3,4,6,7,11b‐hexahydro‐9,10‐dimethoxy‐11b‐methyl [1,4]thiazino[3,4‐a]isoquinoline derivatives
Authors: Jirkovsky I. , Noureldin R.
Published: March 2009

Alkylation of the 2‐mercaptoacetamide 4a with chloropropanone afforded the ketoamide 10 which on direct acid‐catalyzed cyclization furnished 12. The cyclization can be arrested at the stage of the enamide 11. Periodate oxidation of 12 gave the equatorial sulfoxide 14. Reduction of 12 with diborane led to 13 which was oxidized to yield a mixture of sulfoxides 17 and 18. The configuration of 12, 14, 17, and 18 was established on the basis of nmr data. Compounds 12, 14, and 18 showed an interesting degree of antihypertensive activity.
9‐β‐D‐ribopyranosylhypoxanthine, a minor component produced by streptomyces antibioticus
Authors: Kern D. L. , Cook P. D. , French J. C.
Published: March 2009

9‐β‐d‐Ribopyranosylhypoxanthine was isolated from fermentation broths of Streptomyces antibioticus. Its structure was proved by synthesis.
Sur les orthoamino formyl quinoléines, nouveaux synthons hétérocycliques
Authors: Godard Alain , Quéguiner Guy
Published: March 2009

Les quatre ortho amino formyl quinoléines substituées sur le cycle pyridinique ont été synthétisées par oxydation des amino hydroxyméthyl quinoléines correspondantes. Parmi toutes les méthodes envisagées, seule cette dernière a permis la préparation de l'amino‐3 formyl‐2 quinoléine, composé relativement peu stable. Ces nouveaux composés bifonctionnels dérivés de la quinoléine constituent des synthons particulièrement intéressants pour l'élaboration de certains hétérocycles.
Folate antagonists. 17. Synthesis and biological properties of a 2,4‐diamino‐6‐thioquinazoline analog of aminopterin
Authors: Werbel Leslie M. , Newton Linda , Elslager Edward F.
Published: March 2009

A multistep route for the synthesis of N‐[4‐[(2,4‐diamino‐6‐quinazolinyl)thio]benzoyl]‐L‐glutamic acid (2) from 4‐mercaptobenzoic acid and 5‐chloro‐2‐nitrobenzonitrile is described. Although this aminopterin analog lacked significant antimalarial activity, it was a potent inhibitor of dihydrofolate reductase from Trypanosoma cruzi. The pteroic ester analog 11, however, was active against Plasmodium berghei infections in mice at high doses.
4‐Substituted‐3‐alkyl‐3,4‐dihydro‐2H‐1,3‐benzoxazin‐2‐ones. IV (2‐4). Keto‐Enol tautomerism of β‐keto ester derivatives. Reaction of β‐dicarbonyl compounds with diamines
Authors: Bobowski George , Shavel John
Published: March 2009

A series of α‐[3‐alkyl‐3,4‐dihydro‐2‐oxo‐2H‐1,3‐benzoxazin‐4‐yl]‐β‐keto ester derivatives 1 (Table I) were synthesized by the condensation of 3‐alkyl‐3,4‐dihydro‐4‐hydroxy‐2H‐1,3‐benzoxazine‐2‐ones 3 (2) with β‐keto esters 4 in the presence of traces of mineral acids under azeotropic conditions. Condensation of 1 with hydrazines 5 gave pyrazolone derivatives 2 (Table II). Condensation of β‐diketone derivatives 6 with hydrazines 5 and with 1,2‐benzenediamine (8) resulted in the formation of pyrazoles (7a‐c) and diazepine derivatives 12 (Table III) and 13, respectively.
Selenium heterocycles. XXXI. Reaction of ethyl propiolate with 5‐phenyl‐2‐thioxo‐1,3‐thiaselenole and 4‐phenyl‐2‐thioxo‐1,3‐dithiole
Authors: Shafiee A. , Assadi F.
Published: March 2009

Reaction of ethyl propiolate with 4‐phenyl‐2‐thioxo‐1,3‐dithiole afforded 4‐carbethoxy‐2‐thioxo‐1,3‐dithiole in high yield. Reaction of ethyl propiolate with 5‐phenyl‐2‐thioxo‐1,3‐thiaselenole gave 4‐carbethoxy‐2‐thioxo‐1,3‐thiaselenone (IX), 4‐carbethoxy‐2‐selenoxo‐1,3‐dithiole (X) and 5‐carbethoxy‐2‐thioxo‐1,3‐thiaselenole (XI). A possible mechanism for the formation of these compounds is given.
Triphenylphosphonium‐alloxan betaines
Authors: Adams William E. , Heindel Ned D.
Published: March 2009

Alloxan and 1,3‐dimethylalloxan react with triarylphosphines to generate zwitterionic adducts involving the phosphorus and the C‐5 carbonyl oxygen atoms of alloxan. The adducts, unlike alloxan, did not induce permanent hyperglycemia but one analog did effect a transient rise in blood glucose.
Dihydrothiazolopurines
Authors: Montgomery John A. , Thomas H. Jeanette
Published: March 2009

Reaction of 1,2‐dibromoethane with 2‐mercaptoadenine gave both 4‐amino‐7,8‐dihydrothiazolo[2,3‐b]purine (2) and the isomeric 3,6,7,9‐tetrahydro‐9‐iminothiazolo[3,2‐a]purine (3). These tricyclic structures were identified by Raney nickel reduction to the corresponding 3‐ and 1‐ethyladenines.
The synthesis of 2‐methylchromone‐3‐carboxylic acid
Authors: Charlton J. L. , Lypka G. , Sayeed V.
Published: March 2009

A new synthesis of 2‐methyl‐4‐oxo‐4H‐1‐benzopyran‐3‐carboxylic acid (2‐methylchromone‐3‐carboxylic acid from salicyloyl chloride and the enamine of ethyl acetoacetate, is described and compared with the classical synthesis.
Studies on the oxidation of phenothiazine derivatives
Authors: Anderson E. L. , Post A. , Staiger D. S. , Warren R.
Published: March 2009

The sulfoxides of pharmacologically active phenothiazine derivatives have been widely studied as biological transformation products in body fluids and tissue (1,2). The majority of the work has been devoted to the development of analytical techniques for detection of these products (2,3,4).
Synthesis and absolute configuration of 3‐ethyl and 3‐n‐propylpyrrolidine
Authors: Bettoni Giancarlo , Cellucci Carla , Berardi Francesco
Published: March 2009

Optically active 3‐ethyl and 3‐n‐propylpyrrolidine were prepared by two independent routes from their corresponding succinic acids and the absolute configurations were assigned. Maximum optical rotation was also established through evaluation of the degree of racemization of the products obtained via both synthetic routes.
A convenient and general synthesis of 2‐amino‐1,3,4‐thiadiazoles. Dehydration of acylthiosemicarbazides with methanesulfonic acid
Authors: Kress Thomas J. , Costantino Silvio M.
Published: March 2009

2‐Amino‐5‐alkyl and 2‐amino‐5‐aryl‐1,3,4‐thiadiazoles were prepared by the dehydration of 2‐acylthiosemicarbazides with molar equivalents of methanesulfonic acid in refluxing toluene. The synthesis appears to be general.
A benzofuran analog of chloramphenicol
Authors: Bevinakatti Hanamanthsa S. , Badiger Virupax V.
Published: March 2009

Preparation of dl‐threo‐2‐dichloroacetamido‐1‐(2‐benzofuranyl)propane‐1,3‐diol (VI), adopting the method of Sorm, et al, has been described. The structures of the final compound (VI) as well as of the two precursors (V and IV) have been confirmed by ir, nmr and mass spectral studies.
The use of 3,5‐dimethyl‐4‐nitroisoxazole for the preparation of α,β‐unsaturated aromatic acids
Authors: Sarti‐Fantoni P. , Donati D. , Fiorenza M. , Moschi E. , Dal Piaz V.
Published: March 2009

A series of α,β‐unsaturated aromatic acids were prepared by alkaline hydrolysis of 3‐methyl‐4‐nitro‐5‐styrylisoxazoles.
Synthesis of 2‐carboxy‐4‐methylazetidine. A novel isomeric analog of dl‐proline
Authors: Soriano David S. , Podraza Kenneth F. , Cromwell Norman H.
Published: March 2009

L‐Azetidine‐2‐carboxylic acid is a naturally occurring azetidine currently used in the synthesis of abnormally high molecular weight polypeptides. The synthesis of 2‐carboxy‐4‐methylazetidine is now reported which is a novel isomeric analog of dl‐proline. Reaction of α,β‐dibromo carbonyl ester with three molar equivalents of benzylamine yields 1‐benzyl‐2‐carbomethoxy‐4‐methyl‐azetidine. Hydrolysis of the latter compound with barium hydroxide yields 1‐benzyl‐2‐carboxyl‐4‐methylazetidine which, if subjected to catalytic hydrogenation., yields the title compound in practical yield. The cis configuration is tentatively assigned to the title compound on the basis of previously published arguments.
Pyrrolo[1,2‐d]triazines‐1,2,4. I. Dérivés pyrroliques
Authors: Lancelot Jean Charles , Maume Daniel , Robba Max
Published: March 2009

La synthèse d'hydrazides pyrroliques a été effectuée à partir de l'hydrazide de l'acide pyrrole‐carboxylique‐2 et celle d'hydrazones pyrroliques à partir du pyrrole‐carboxaldéhyde‐2. Les pyrrolyl‐2 oxadiazoles et thiadiazoles sont accessibles par cyclisation des hydrazides pyrroliques avec l'oxychlorure et le décasulfure de phosphore. Ces dérivés sont destinés à la synthèse de pyrrolo[1,2‐d]triazines‐1,2,4 par cyclisation ou par réarrangement.
Carbon‐13 nuclear magnetic resonance spectra of substituted‐s‐triazolyl tetrazoles
Authors: Kothari Paresh J. , Stenberg Virgil I. , Singh Shiva P. , Parmar Surendra S. , Zoellner Robert W.
Published: March 2009

The natural abundance carbon‐13 nuclear magnetic resonance spectra of various 5‐aryltetrazoles, 1‐(5‐aryltetrazol‐2‐ylacetyl)‐4‐phenyl thiosemicarbazides and 5‐(5‐aryltetrazol‐2‐ylmethyl)‐4‐phenyl‐s‐triazole‐3‐thiols were recorded using Fourier transform techniques. The chemical shifts of various carbon resonances have been assigned on the basis of chemical shift theory, the signal multiplicity observed in the single‐frequency off‐resonance decoupled (SFORD) spectra and comparison with the chemical shifts of the model compounds.
Oxidative cyclization of morusin
Authors: Nomura Taro , Fukai Toshio , Matsumoto Junko
Published: March 2009

Oxidative cyclization of morusin (I) by using one‐electron transfer oxidizing agents (manganese dioxide, silver oxide) afforded morusin hydroperoxide (II). A similar reaction was carried out in the presence of 2,4,6‐tri‐t‐butylphenol, a radical quencher, to give compounds (IV, V, VI and VII) coupled with the 2,4,6‐tri‐t‐butylphenoxy radical. On the basis of above results, the possible mechanism of this oxidative cyclization was discussed. In addition, morusin hydroperoxide (II) was also obtained by photo‐sensitized oxidation of morusin (I) in the presence of sensitizers (Rose Bengal, hematoporphyrin). To elucidate the reaction mechanism similar reactions were carried out in the presence of radical quencher (2,4,6‐tri‐t‐butylphenol) or singlet oxygen quencher (triethylenediamine). From these results, the possible mechanism of the formation of morusin hydroperoxide (II) from morusin (I) was discussed.
Heterocycles from substituted amides. VII Oxazoles from 2‐isocyanoacetamides
Authors: Chupp John P. , Leschinsky Kindrick L.
Published: March 2009

Certain heretofore unknown tertiary α‐isocyanacetanilides 1 are reported for the first time, prepared by methods necessarily different from those employed to prepare the previously cited aliphatic α‐isocyano‐acetamides 2. Like 2, 1 has been shown to readily undergo dialkylation with alkyl halides. Moreover, 1 also gives rise to oxazole and oxazoline derivatives upon reaction with acyl halides and aldehydes, respectively, resembling the similarly activated α‐isocyano esters and sulfones. Further, in a demonstrable ring‐chain tautomeric equilibration, apparently restricted to tertiary amides, 1 readily cyclizes, providing the only known synthesis of 5‐amino‐2,4‐unsubstituted oxazoles 3. In other examples 4‐chloro and 4‐alkyl‐5‐amino‐oxazoles are produced. The materials and reactions are characterized, and compared with previous related studies.
Heterocycles from substituted amides. VIII Oxazole derivatives from reaction of isocyanates with 2‐isocyanoacetamides
Authors: Chupp John P. , Leschinsky Kindrick L.
Published: March 2009

A facile reaction of 2‐isocyanoacetamides 1 with reactive aryl and sulfonyl isocyanates is shown to give 5‐amino‐2‐oxazolecarboxamides 3 in a reaction arising from electrophilic attack of isocyanate with the nucleophilic isocyanide carbon. This reaction, perhaps proceeding through an unstable nitrile ylid intermediate reminiscent of the Cornforth rearrangement, is a first example of ring closure via acylation, involving the activated methylene of an organic isocyanide, without recourse to added base. Isomeric 5‐amino‐4‐oxazolecarboxamides 4 are formed when 5‐aminooxazoles 2 react with isocyanates. Since 2 has previously been shown to easily form by thermal isomerization of 1, methods now exist for the preparation of both 5‐amino‐ 2‐ and 4‐oxazolecarboxamides from the single starting material 1. In contrast, 1 with acyl isocyanates is shown to give a variety of products, including iminooxazolinediones, 5‐amino‐2‐oxazolecarbox‐amide 3 and 2 (1) pyrazinones (tentatively identified), depending on the structure of the isocyanates.
Formation d'hydroxy‐5 méthyl‐5 isoxazolidinones‐3 par action du dicétène sur les hydroxylamines
Authors: Perronnet Jacques , Girault Pierre , Demoute Jean‐Pierre
Published: March 2009

L'action du dicétëne sur les hydroxylamines monosubstituées à l'azote conduit à des dérivés cycliques de type hydroxy‐5 méthyl‐5 isoxazolidinone‐3.
Heteroacyl azides as acylating agents for aromatic or heteroaromatic amines
Authors: Stanovnik B. , Tišler M. , Golob V. , Hvala I. , Nikolić O.
Published: March 2009

The possibility of formation of substituted heterocyclic amides from heteroacyl azides and aromatic or heteroaromatic amines was investigated. Although acylation proceeded in some cases under mild reaction conditions, formation of N,N′‐disubstituted ureas was the main process at elevated temperatures.
Syntheses of covalently‐linked porphyrin‐quinone complexes
Authors: Kong Josephine L. Y. , Loach Paul A.
Published: March 2009

A synthetic route for the preparation of covalently‐linked porphyrin‐quinone and metalloporphyrin‐quinone complexes as models for the phototrap in bacterial photosynthesis is described. 5‐(4‐Carboxyphenyl)‐10,15,20‐tritolylporphyrin, prepared by a mixed aldehyde approach, was attached to a benzoquinone center with a propanediol bridge by means of ester linkages. The starting point for the benzoquinone moiety was 2,5‐dihydroxyphenylacetic acid, whose hydroquinone function was first protected by preparing its dimethyl ether. The spacing between the two centers of the complex could be altered simply by varying the length of the bridging group (a diol) employed. Boron tribromide was used to unmask the quinol derivatives in the final coupled products. The zinc(II) derivative of porphyrin‐quinone complex was prepared by addition of a saturated solution of zinc acetate in methanol to a solution of the corresponding porphyrin‐hydroquinone complex in dichloromethane at room temperature. The structures of these complexes were confirmed by nmr spectroscopy, uv‐visible absorption, and mass spectroscopy. Oxidation of the quinol moiety in the covalently‐linked complex to its corresponding quinonoid derivative was accomplished by treating a solution of the complex in dichloromethane with a stoichiometric amount of 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone, a high potential benzoquinone.
Benzomorphan related compounds. XII 2,5‐Methanothieno[3,2‐g]quinolines as rigid bridged thienomorphans
Authors: Bosch J. , Alvarez M. , Granados R.
Published: March 2009

The preparation of a 1,2,3,4,4a,5,9,9a‐octahydro‐2,5‐methanothieno[3,2‐g]quinoline, which can be considered as a rigid thieno[3,2‐f]morphan system due to an additional two‐atoms bridge between the 3 and 9 positions of the morphan nucleus, is described. The synthetic route involved the acidic cyclization of a 3‐(2‐thenyl)‐2‐azabicyclo[2.2.2]oct‐7‐ene, obtained by the Diels‐Alder reaction between 1,3,4‐trimethyl‐2‐(2‐thenyl)‐1,2‐dihydropyridine and ethyl acrylate.
New practical synthesis of prazosin
Authors: Honkanen Erkki , Pippuri Aino , Kairisalo Pekka , Thaler Heinrich , Koivisto Maija , Tuomi Sirpa
Published: March 2009

A new four step synthesis of prazosin, 2‐[4‐(2‐furoyl)piperazin‐l‐yl]‐4‐amino‐6,7‐dimethoxyquinazoline, has been described. The method is also adaptable for the preparation of other substituted 4‐aminoquinazolines. The yields are good in every step and the reactions are performed with ease. Prazosin hydrochloride of high purity is obtained directly in the last step.
Studies on novel heterocyclic ring systems. Reaction of 4‐hydroxylcoumarin with o‐aminobenzaldehyde and 2‐mercaptoaniline
Authors: Tabaković K. , Tabaković I. , Trkovnik M. , Jurić A. , Trinajstić N.
Published: March 2009

Reactions of 4‐hydroxycoumarin (1) with o‐aminobenzaldehyde (2) and 2‐mercaptoaniline (5) have been investigated. The yet unreported 6,12‐dihydro‐l‐benzopyrano[3,4‐b][1,4]benzothiazin‐6‐one (6) system has been synthesized and characterized on the basis of spectral and analytical data. A novel synthetic route to 6H‐l‐benzopyrano[4,3‐b]quinolin‐6‐one (4) is reported. HMO calculations predict the most reactive sites on the molecules.
Rearrangement of a pyranone to a benzothiazole
Authors: White R. L. , Schwan Thomas J. , Alaimo R. J.
Published: March 2009

The conversion of 2‐chloromethyl‐5‐methoxy‐4H‐pyran‐4‐one to 2‐amino‐5‐hydroxy‐6‐methoxybenzothiazole hydrochloride under mild reaction conditions has been observed. The synthesis of the identical benzothiazole by an alternate unequivocal method is also reported.
3,3‐Dinitrobutyl‐1,2,4‐oxadiazoles
Authors: Bjorklund Mark D. , Coburn Michael D.
Published: March 2009

The syntheses of 3,5‐bis(3,3‐dinitrobutyl)‐1,2,4‐oxadiazole and a series of 3‐aryl‐5‐(3,3‐dinitrobutyl)‐1,2,4‐oxadiazoles were accomplished by treating 4,4‐dinitropentanoyl chloride with the appropriate amidoximes to yield the intermediate O‐(4,4‐dinitropentanoyl)amidoximes, which were dehydrated to the 1,2,4‐oxadiazoles.
Nouvelle synthése de dioxènes‐1,4
Authors: Bacquet Cathy , Einhorn Jacques , Lelandais Daniel
Published: March 2009

Nous décrivons la synthèse de quelques dioxénes‐1,4 connus ou nouveaux à partir des methoxy‐2 dioxannes‐1,4 correspondants obtenus par voie électrochimique.
5‐Amino‐4,5‐dihydroisoxazoles. Part II . Reactions of 5‐amino‐3‐aryl‐4‐methylene‐4,5‐dihydroisoxazoles with Nucleophiles
Authors: Pocar Donato , Rossi Luisa Maria , Scorca Franca , Trimarco Pasqualina
Published: March 2009

Several 5‐amino‐3‐aryl‐4‐methylene‐4,5‐dihydroisoxazoles were reacted with methoxide, benzenethiolate, benzenethiol, carboxylic acids and secondary amines. Addition and/or addition‐elimination products were obtained. Reaction mechanisms are discussed.
An HMO study of the azo‐hydrazone tautomerism in diazonium coupling products of 5‐isoxazolones
Authors: Párkányi Cyril , Shawali Ahmad S.
Published: March 2009

The HMO method has been used to study tautomerism in 3‐substituted 4‐arylazo‐5‐isoxazolones (2), the possible tautomeric structures being 2a‐2d. Also the common anions of these tautomers, 6, have been theoretically studied. In addition to the free molecules, HMO calculations have been carried out for structures with hydrogen bonds to protic solvents, for tautomers with intramolecular hydrogen bonds, and for dimers formed via intermolecular hydrogen bonds. In all these situations, the hydrazone form 2a has been shown to be most stable. Also the inductive effect of electron‐donating and electron‐withdrawing substituents in the arylazo moiety upon the stability of various tautomers has been investigated. The results obtained on the basis of HMO calculations are in full agreement with the experimental data of Summers and co‐workers. Several m‐ and p‐substituted 4‐arylazo‐3‐methyl‐5‐isoxazolones have been synthesized and their spectral data and melting points reported.
[1]Benzothienopyrimidines. I. Etude de la 3H‐benzothieno[3,2‐d]pyrimidone‐4
Authors: Robba Max , Touzot Paulette , ‐El‐Kashef Hussein
Published: March 2009

La 3H‐benzothiéno[3,2‐d]pyrimidone‐4 (3) a été synthétisée par cyclisation bimoléculaire de l'amino‐3 carbéthoxy‐2 benzothiophéne (1) avec le formamide. Les réactions électrophiles effectuées sur la benzo‐thiénopyrimidone (3) conduisent à des dérivés de substitution sur l'azote lactamique dont la structure a été prouvée par 1H rmn et au moyen de synthèses univoques. La benzothiéno[3,2‐d]pyrimidone (3) permet d'accéder à la benzothiéno[3,2‐d]pyrimidine (7) soil par l'intermédiaire de la 3H‐benzothiéno[3,2‐d]‐pyrimidinethione‐4 (6), soit par l'intermédiaire de la chloro‐4 benzothiéno[3,2‐d]pyrimidine (4) et de l'hydrazino‐4 benzothiéno[3,2‐d]pyrimidine (5).
Benzomorphan related compounds. XIII. Syntheses of 2,6‐methanopyrrolo[1,2‐d] [1,4]diazocines
Authors: Bosch J. , Mauleón D. , Granados R.
Published: March 2009

Two alternative syntheses of 2,6‐methanopyrrolo[1,2‐d][1,4]diazocines (I) based in the acidic cyclization of 2‐(1‐pyrrolylmethyl)tetrahydropyridines are described. In the first synthetic route, lithium aluminum hydride reduction of 2‐cyano‐1,4‐dimethyl‐1,2,3,6‐tetrahydropyridine (IIa) followed by reaction of the resulting primary amine with 2,5‐diethoxytetrahydrofuran affords the requisite tetrahydropyridine IVa. An analogous sequence from 2‐cyano‐4,6‐di‐methylpyridine (V) leads to the corresponding 2‐(1‐pyrrolylmethyl)pyridine VII which by quaternization and borohydride reduction yields a mixture of isomeric tetrahydropyridines, precursors of the pyrrolodiazocine systems Ib and Ic. Structural and stereochemical assignment of the synthesized compounds are discussed.
New heterocyclic systems. Benzo[4,5]cyclohepta[1,2‐b]pyrrole and benzo[5,6]cyclohepta[1,2‐f]pyrrolizidine derivatives
Authors: Ackrell J. , Franco F. , Guzmàn R. Greenhouse A. , Muchowski J. M.
Published: March 2009

The synthesis of the polycyclic pyrrole acetic acids 9e, 13e and 13g by multistep processes from 1‐bromo‐4‐phenylbutan‐2‐one (6c) is reported. An instance of the use of the 2‐chloroethyl moiety as a pyrrole nitrogen protecting group is described. The α‐methylaminoketone (6e) was synthesised by a novel two step process from 6c and methyl N‐methylformimidate (12).
Diels‐alder reaction of 2‐chloro‐2‐nitrosopropane with 1,3‐cyclohexadiene
Authors: Kesler Ewa
Published: March 2009

3‐(2‐Chloropropyl)‐2‐oxa‐3‐azabicyclo[2.2.2]oct‐5‐ene and 2‐oxa‐3‐azabicyclo[2.2.2]oct‐5‐ene hydrochloride have been prepared by cycloaddition of 2‐chloro‐2‐nitrosopropane to 1,3‐cyclohexadiene and their structure determined by nmr, using a 1H nmr shift reagent.
Reaction of N‐cyanoformimidates with some heterocyclic compounds. A new synthesis of 5‐azaadenine and related compounds
Authors: Lalezari I. , Nabahi S.
Published: March 2009

3‐Amino‐1,2,4‐triazoles and 2‐aminobenzimidazole were reacted with N‐cyanoimidates to give 5‐amino‐1,2,4‐triazolo[2,3‐a]‐1,3,5‐triazines (5‐azaadenines) and 4‐aminobenzimidazo[1,2‐a]‐1,3,5‐triazines, respectively. The structures of the compounds obtained were confirmed through the comparison with some of the possible isomers prepared by independant methods.
Synthesis of a 4‐hydroxyisoquinolin‐1‐one and a related dibenzo[α,g]quinolizin‐8‐one
Authors: Coyle J. D. , Challiner J. F. , Haws E. J. , Newport G. L.
Published: March 2009

Aqueous acid converts the imidazo[4,3‐α]isoindol‐5‐one 2 to a 4‐hydroxyisoquinolin‐1‐one (3). A related imidazoisoindolone 6, obtained by photochemical cyclization of the Mannich base from 1,2,3,4‐tetrahydro‐isoquinoline, formaldehyde and phthalimide, gives a dibenzo[a,g]quinolizin‐8‐one (7) in a similar reaction.
Chemistry of the phenoxathiins and isosterically related heterocycles. XII. Synthesis of diazaphenoxathiin analogs: 1,9‐Diazaphenoxathiin and 1,7‐diazaphenoxathiin
Authors: Caldwell Steven R. , Turley James C. , Martin Gary E.
Published: March 2009

The synthesis of the first diazaphenoxathiins, 1,9‐diazaphenoxathiin and 1,7‐diazaphenoxathiin, are described. Complete assignments are made for the 13C‐nmr spectra of these compounds based on additivity correlation and 1H‐13C spin‐coupling constants. The isolation and confirmation of the structure of 2‐[2′(‐3′‐nitropyridylthio)]‐3‐[2″‐(3″‐nitropyridyloxy)] pyridine using 13C‐nmr and appropriate model compounds is also discussed. A preliminary evaluation of spontaneous motor depression in mice showed a substantial difference between the observed activities of the two diazaphenoxathiins reported. The possibility of the observed difference being associated with the relative positions of the annular aza‐substitutions is discussed.
Confirmation of the structure of the bicyclic oxidation product of dehydroascorbic acid bis‐phenylhydrazone
Authors: El Khadem Hassan S. , El Ashry El Sayed H. , Jaeger David L. , Kreishman George P. , Foltz Rodger L.
Published: March 2009

The structure of the bicyclic oxidation product of dehydro L‐ascorbic acid has been confirmed by detailed mass spectroscopy and 13C nmr spectroscopy as 3. This structure was put in doubt, when electron ionization mass spectroscopy detected a molecular peak two mass units higher than expected. Careful experiments at low temperature revealed that the molecular ion disproportionates when heated, giving ion 2 or one of its isomers.
Hydrazidoyl halides in synthesis of Δ2‐1,3,4‐selenadiazolin‐5‐ones
Authors: Hassaneen Hamdi M. , Shetta Abdelfattah , Shawali Ahmad S.
Published: March 2009

Reaction of hydrazidoyl halides 1‐5 with potassium selenocyanate in ethanol produces the corresponding 2,4‐disubstituted‐5‐iminoδ2‐1,3,4‐selenadiazolines, 9‐13 respectively. Nitrosation of the latter yields the N‐nitroso derivatives 14‐17, which decompose upon refluxing in xylene to give 2,4‐disubstituted Δ2‐1,3,4‐selenadiazolin‐5‐ones in good yield. Compounds 9‐13 give the respective N‐acetyl derivatives 22‐26 and N‐benzoyl derivatives 27‐31 with acetic anhydride and benzoyl chloride in pyridine.
Synthesis of 4‐amino[1] benzofuro[3,2‐g] cinnolines
Authors: Ladurée D. , Florentin D. , Robba M.
Published: March 2009

The synthesis of the new heterocycles, 4‐amino[1]benzofuro[3,2‐g]cinnolines, was accomplished by the intramolecular cyclization of the Z‐configuration of cyanoarylhydrazones. The latter compounds were obtained via interaction between the diazonium salt of 3‐amino‐dibenzofuran and various active methylene compounds via the Japp‐Klingemann reaction. The alkaline treatment of azo intermediates 4, which may be isolated in the course of condensation, gave the corresponding cyanoarylhydrazones 5. A study of the configuration and possible isomerisations is reported.
Reaction of sulfene and dichloroketene with open‐chain N,N‐disubstituted α‐aminomethyleneketones. Synthesis of N,N‐disubstituted 4‐amino‐3,4‐dihydro‐(5‐methyl‐6‐phenyl)(5,6‐diphenyl)‐1,2‐oxathiin 2,2‐dioxides and of 4‐amino‐3‐chloro‐5‐methyl‐6‐phenyl‐2H‐pyran‐2‐ones
Authors: Bargagna Alberto , Schenone Pietro , Bondavalli Francesco , Longobardi Mario
Published: March 2009

Cycloaddition of sulfene to N,N‐disubstituted 3‐amino‐2‐methyl‐1‐phenyl‐2‐propen‐1‐ones (I) and 3‐amino‐1,2‐diphenyl‐2‐propen‐1‐ones (II) occurred in good to moderate yield only in the case of aliphatic N‐substitution to give 4‐dialkylamino‐3,4‐dihydro‐(5‐methyl‐6‐phenyl)(5,6‐diphenyl)‐1,2‐oxathiin 2,2‐dioxides. Polar 1,4‐cycloaddition of dichloroketene to I and II occurred only in the former case, giving in good to moderate yield N,N‐disubstituted 4‐amino‐3,3‐dichloro‐3,4‐dihydro‐5‐methyl‐6‐phenyl‐2H‐pyran‐2‐ones which were dehydrochlorinated with DBN to N,N‐disubstituted 4‐amino‐3‐chloro‐5‐methyl‐6‐phenyl‐2H‐pyran‐2‐ones.

In the reaction of 2‐methyl‐1‐phenyl‐3‐diphenylamino‐2‐propen‐1‐one with dichloroketene, a product was isolated which was proven by uv, ir, nmr and chemical evidence to be the dipolar ion VI, the supposed intermediate of the polar 1,4‐cycloaddition of dichloroketene to N,N‐disubstituted enaminones.
Reissert compound studies. XXXVII. Attempts to form reissert compounds from quinazoline and cinnoline
Authors: Bhattacharjee D. , Popp F. D.
Published: March 2009

Reaction of quinazoline with trimethylsilyl cyanide and benzoyl chloride gave 2,4‐dicyano‐1,3‐dibenzoyl‐1,2,3,4‐tetrahydroquinazoline as the major product. This compound undergoes monoalkylation with methyl iodide in the presence of sodium hydride. Reaction of cinnoline with trimethylsilyl cyanide and benzoyl chloride gave 1,2‐dibenzoyl‐4‐cyano‐1,2‐dihydrocinnoline.
Substituted thiosemicarbazido/semicarbazido quinolines as possible antimalarials
Authors: Mehrotra Suman , Barthwal Jayanti P. , Pandey Bhagwan R. , Bhargava Krishna P. , Parmar Surendra S.
Published: March 2009

Several 2‐aryl substituted thiosemicarbazido‐4‐methyl‐6‐methoxyquinolines and 2‐aryl substituted semi‐carbazido 4‐methyl‐6‐methoxyquinolines were synthesized and evaluated for their antimalarial activity in mice infected withPlasmodium berghei. Two of these substituted quinolines were found to exhibit 50% clearance in a dose of 500 mg./kg. administered intraperitoneally for 5 days.
Reductive opening of the thiazolidine ring. Selective N‐methylation of cysteamines
Authors: Melchiorre Carlo , Giardinà Dario , Angeli Piero
Published: March 2009

The reaction of thiazolidines 2 and 7 with borane was investigated. It gave N‐methylcysteamines 3 and 8 through thiazolidine ring opening. Sodium borohydride and lithium aluminum hydride were ineffective.
Methylation of 4‐phenyl‐1,2,3‐thiadiazole. Reaction of nucleophiles with N‐methyl‐1,2,3‐thiadiazolium salts and the crystal structure of the products
Authors: Auricchio S. , Brückner S. , Giunchi L. Malpezzi , Kozinsky V. A. , Zelenskaja O. V.
Published: March 2009

The methylation of 4‐phenyl‐1,2,3‐thiadiazole yields both N‐methylated products. These react differently with nucleophiles. The structure of the product of the reaction with morpholine has been determined through X‐ray diffraction analysis.
Synthesis of some 3,7‐disubstituted quino[3,2‐c][1,8]naphthyridines
Authors: Da Settimo Antonio , Biagi Giuliana , Primofiore Giampaolo , Ferrarini Pier Luigi , Livi Oreste , Marini Anna Maria
Published: March 2009

The preparation of some 3,7‐disubstituted‐5,6‐dihydroquino[3,2‐c][1,8]naphthyridines (6) by the condensation of 7‐substituted‐2,3‐dihydro‐1,8‐naphthyridin‐4‐(1H)ones (5) with o‐aminoacetophenone or o‐aminobenzophenone is described. All the 5,6‐dihydroderivatives 6 were transformed into the fully aromatic compounds 7 by heating with nitrobenzene. Only a few quino[3,2‐c][1,8]naphthyridines were previously described.