摘要:

AbstractThe synthesis of various purine nucleosides by cyclization of AICA‐riboside(5‐amino‐1‐β‐D‐ribofuranosylimidazole‐4‐carboxamide) is described. A variety of cyclization reactions provide new synthetic routes to inosine and guanosine. In this review, emphasis will be placed on the synthes

ISSN:0022-152X    

DOI:10.1002/jhet.5570150301

出版商:Wiley‐Blackwell    

年代:1978

数据来源: WILEY

摘要:

AbstractTreatment of 1,3‐dimethyl‐6‐hydrazinouracil with the appropriate dimethylformamide dialkylacetal afforded the, corresponding 2‐alkyl‐5,7‐dimethylpyrazolo[3,4‐d]pyrimidine‐4,6‐(5H,7H)diones. The reaction of 1,3‐dimethyl‐6‐(α‐methylbenzylidenehydrazino)uracils with dimethylformamide dimethylacetal or triethyl orthoformate gave the corresponding 5,7‐dimethyl‐2‐vinylpyrazolo[3,4‐d]pyrimidine‐4,6(5H,7H)diones, respectively. Similarly, treatment of 1,3‐dimethyl‐6‐(α‐methylbenzylidenehydrazino)uraeils with triethyl orthopropionate yielded the corresponding 5,7‐dimethyl‐3‐ethy

ISSN:0022-152X    

DOI:10.1002/jhet.5570150302

出版商:Wiley‐Blackwell    

年代:1978

数据来源: WILEY

摘要:

AbstractThe synthesis and electronic absorption spectra of some pyranylidene trimethine pyrylium salts are described.

ISSN:0022-152X    

DOI:10.1002/jhet.5570150303

出版商:Wiley‐Blackwell    

年代:1978

数据来源: WILEY

摘要:

Abstract2‐[4‐(1‐Oxo‐2‐isoindolinyl)phenyl]propanoic acid (1) having a potent analgesic and anti‐inflammatory activity could be obtained by three methods, which were found to provide extremely useful ways for the synthesis of1from the industrial point of view. (E)‐ and (Z)‐Isomers of 2‐butenoic acid and oxiranecarboxylic acid derivatives as the intermedaites in the synthesis of1were separated and characterized. Furthermore, the optical resolution of (±)‐2‐[4‐(1‐oxo‐2‐isoindolinyl)phenyl]propanoic acid was successfully achieved using cincho

ISSN:0022-152X    

DOI:10.1002/jhet.5570150304

出版商:Wiley‐Blackwell    

年代:1978

数据来源: WILEY

摘要:

AbstractUnder both weakly and strongly alkaline conditions, 1‐alkyl‐2,5‐dithiobiureas (1‐alkyl‐thiocarbamoyl‐3‐thiosemicarbazides) form 4‐alkyl‐5‐amino‐1,2,4‐triazoline‐3‐thiones and 4‐alkyl‐1,2,4‐triazolidine‐3,5‐dithiones in varying proportions. 1‐Alkoxythiocarbonyl‐3‐thiosemicarbazides expel hydrogen sulfide under weakly basic conditions to form the corresponding 5‐alkoxy‐1,2,4‐triazoline‐3‐thiones. In a strongly alkaline environment, however, these alkoxy‐thiocarbonyl thiosemicarbazides eliminate alcohol to form the appropriate 1,2,4‐triazolidine‐3,5‐dithiones. 1‐Alkoxycarbonyl‐3‐thiosemicarbazides eliminate alcohol in both weakly and strongly basic media to give 5‐thiono‐1,2,4‐triazolidine

ISSN:0022-152X    

DOI:10.1002/jhet.5570150305

出版商:Wiley‐Blackwell    

年代:1978

数据来源: WILEY

摘要:

AbstractThe reaction of aroylphenylacetylenes (I) with acyl‐ or aroylhydrazines (II) gave ω‐aroyl‐acetophenone‐N‐acyl orN‐aroylhydrazones (IV). The latter gave upon treatment with methanolic potassium hydroxide and with acetic anhydride in the presence of sodium acetate, the corresponding pyrazoles (V) and theN‐acetylpyrazoles (VII and VIII), respectively. The acetylenic ketones (1) also reacted with methylhydrazine and 1,1‐dimethylhydrazine to give 5‐aryl‐1‐methyl‐3‐phenylpyrazoles (XII), and 1,1‐dimethylhydrazine derivatives (XIII), respectively. When the latter compounds were heated with acetic anhydride, they gav

ISSN:0022-152X    

DOI:10.1002/jhet.5570150306

出版商:Wiley‐Blackwell    

年代:1978

数据来源: WILEY

摘要:

AbstractThe molecular structure of 1,6‐dimethyl‐7‐ethoxycarbonylpyrazolo[1,5‐d]tetrazole, a 3a‐azapentalene derivative having only nitrogens as ring heteroatoms, has been determined by X‐ray dif‐raction. The compound crystallizes in the space group P21/a with four molecules in a unit cell of dimensions a = 10.184, b = 28.827, c = 4,090 Å, β = 123.37°. The structure, which was solved by direct methods and refined to a final value of R = 0.039, shows a clear difference in bond localization in the two fused rings, in agreement with CNDO/2 calculations. The position of theN‐methyl group corroborates an empirical

ISSN:0022-152X    

DOI:10.1002/jhet.5570150307

出版商:Wiley‐Blackwell    

年代:1978

数据来源: WILEY

摘要:

AbstractBy varying the acidity, solvent polarity, and temperature when thiosemicarbazide reacted with ethyl 4‐chloroacetoacetate, ethyl 2‐amino‐6H‐1,3,4‐thiadiazine‐5‐acetate hydrochloride, ethyl 2‐hydrazinothiazole‐4‐acetate, and ethyl 2‐imino‐3‐aminothiazoline‐4‐acetate hydrochloride were prepared selectively. Double bond migration occurred after neutralizing the thiadiazine and thiazoline hydrochlorides to form the α,β‐unsaturated esters: 2‐amino‐5‐carbethoxymethylidene‐4,5‐dihydro‐6H‐1,3,4‐thiadiazine and 2‐imino‐3‐amino‐4‐carbethoxymethylidenethiazolidine. Pmr studies revealed that an equilibrium existed in solution between the imine and enamine tautomers of the thiadiazine free base. In the enamine structure, a 6‐membered hydrogen bonded ring system promotes stability. The thiadiazine contracted in acidic aqueous acetone to ethyl 2‐isopropylidenehydrazonothiazole‐4‐acetate.Monobenzoylation at the primary amine of the thiadiazine yielded ethyl 2‐benzamido‐6H‐1,3,4‐thiadiazine‐5‐acetate without disruption of the hydrogen bonded ring, but benzoylating the imino functionality of the thiazolidine caused deconjugation of the α,β‐unsaturated ester by double bond migration back into the ring, and ethyl 2‐benzimido‐3‐aminothiazoline‐4‐acetate was produced, dehydration yielded ethyl 2‐phenylthiazolo[3,2‐b]‐s‐triazole‐5‐acetate. This compound was also obtained by reacting 3‐phenyl‐1,2,4‐triazole‐5‐thiol with ethyl 4‐chloroacetoacetate, while the monobenzoylated derivative of the hydrazinothiazole, ethyl 2‐(2‐benzoylhydrazino)thiazole‐4‐acetate underwent a dehydrative cyclization to ethyl 3‐phenyl‐thiazolo [2,3‐c]‐s‐triazole‐5‐acetate.In chloroform solvent, the second site of benzoylation on the thiadiazine was ring nitrogen 3 while in ethanol or acetonitrile‐pyridine ring nitrogen 4 was benzoylated instead. Benzoylation at ring nitrogen 3 resulted in deconjugation of the α,β‐unsaturated ester moiety and formed the endocyclic imine, ethyl 2‐benzimido‐3‐benzoyl‐2,3‐dihydro‐6H‐1,3,4‐thiadiazine‐5‐acetate. However, deconjugation of the unsaturated ester did not occur after benzoylation at ring nitrogen 4; the product wastrans‐2‐benzamido‐4‐benzoyl‐5‐carbethoxymethylidene‐4,5‐dihydro‐6H‐1,3,4‐thiadiazine.The hydrogen bonded oximes,syn‐2‐amino‐5‐ethyloxalyl‐6H‐1,3,4‐thiadiazine oxime, 3,3‐dimethyl‐5‐ethyloxalyl‐2H‐1,2,4‐triazolo[3,4‐b]thiazole oxime, and 2‐(2‐benzoylhydrazino)‐4‐ethyloxalylthiazole oxime were synthesized by nitrosation.2‐Amino‐5‐ethyloxalyl‐6H‐1,3,4‐thiadiazine oxime benzoate, 2‐benzamido‐5‐ethyloxalyl‐6H‐1,3,4‐thiadiazine oxime dibenzoate, and the tribenzoylated derivatives, 2‐benzimido‐3‐benzoyl‐5‐ethyloxalyl‐2,3

ISSN:0022-152X    

DOI:10.1002/jhet.5570150308

出版商:Wiley‐Blackwell    

年代:1978

数据来源: WILEY

摘要:

AbstractA synthesis of the novel 4H‐pyrano[4,3‐d]thiazole ring system is described. Derivatives bearing alkylamine and alkanoic acid side chains have been prepared and tested for potential antidepressant and antiinflammatory activities, respectively; only marginal activities were found in these te

ISSN:0022-152X    

DOI:10.1002/jhet.5570150309

出版商:Wiley‐Blackwell    

年代:1978

数据来源: WILEY

摘要:

AbstractPhenanthro[4,5‐bcd]thiophene (1) is converted into phenanthrene (2) (50%) and a mixture of methylphenanthrenes (3) (12%) by means of methanol and a sulfided cobaltous oxide‐molybdic oxide‐aluminum oxide catalyst (CMA‐1) at 450° in a flow system. Similarly,2gives3; and 4‐methylphenanthrene yields2plus3(main component 3‐methylphenanthrene) under the same reaction conditions. Mechanisms of the reactions are discussed. A facile chromatographic separation for 1‐ and 4‐keto‐1,2,3,4‐tetrahydrophenan

ISSN:0022-152X    

DOI:10.1002/jhet.5570150310

出版商:Wiley‐Blackwell    

年代:1978

数据来源: WILEY