摘要:

AbstractThe syntheses of 5‐fluoro‐, 5,7‐difluoroimidazo[4,5‐b]pyridine (5band5e”) and 4‐fluoro‐, 6‐fluoro‐ and 4,6‐difluoroimidazo[4,5‐c]pyridine (5a, 5cand5e) are described. The syntheses are achieved through fluorodechlorination of di‐ and trichloro‐3‐nitropyridines, followed by monoamination, reduction and ring‐closure with diethoxymethyl acetate. The reactivity of the new fluoro‐imidazopy

ISSN:0165-0513    

DOI:10.1002/recl.19760950602

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractDicyclopropylethanedione forms monoclinic crystals with cell constants:a= 6.317,b= 9.990,c= 6.078 Å and β = 90.34°. The space group isP21/nand there are two molecules in the unit cell. The molecules in the crystal are centrosymmetric with the CO groupstranswith respect to each other. Each CO iscisrelative to the adjacent cyclopropane ring (bisected conform

ISSN:0165-0513    

DOI:10.1002/recl.19760950603

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractThe antioxidant action of thiophenes is shown to be due to a heterolytic decomposition of hydroperoxides effected by SO2(H2SO4) which is liberated from the thiophene. Thus, the initiation level in an autoxidizing alkylaromatic compound (n‐hexylbenzene) is decreased and the oxidation is further inhibited by phenol, the heterolysis product of the hydroperoxide. At low thiophene concentrations the inhibition is counterbalanced by the low initiation level in such a way that the oxidation continues to proceed at a constant rate. The effect of substituents, of the concentration and of added bases on the antioxidant activity of thiophenes is reporte

ISSN:0165-0513    

DOI:10.1002/recl.19760950604

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractIn autoxidizingn‐hexylbenzene traces of SO2, evolved from “inactive” thiophenes or from other SO2sources, give rise to an oscillating oxidation with oxygen evolution. This entirely new phenomenon is explained in terms of an SO2‐catalysed homolysis of hydroperoxides, which results in a very high initiatio

ISSN:0165-0513    

DOI:10.1002/recl.19760950605

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractSinglet‐oxygen oxidation of alkyl‐ and aryl‐substituted thiophenes has been studied with respect to product formation and relative rates of reaction. The reactivity of thiophenes towards singlet oxygen decreases with the introduction of electron‐withdrawing groups. A comparison of the nature of the products and the relative reactivities towards singlet oxygen of a number of thiophenes with their previously reported anti‐oxidant behaviour indicates that singlet oxygen plays hardly any significant role, if at all, in the desulfurization of thiophenes under autoxidative c

ISSN:0165-0513    

DOI:10.1002/recl.19760950606

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractUsing ethyl glycinate (I) as starting material, afterNα‐benzyloxycarbonyl‐nitroarginylproline [ZArg(NO2)‐Pro,II]* had been coupled to it with the aid of excess mixed anhydride, and after acidolysis, the tripeptide Arg(NO2)‐Pro‐Gly‐OEt was obtained. By means of the repetitive excess mixed anhydride (REMA) method the protected decapeptide sequence (X) of the luteinizing hormone‐releasing hormone (LHRH) was synthesized (Scheme). In the course of this process, at the heptapeptide stage, theC‐terminal ethyl ester (VIIa) was converted by ammonolysis into the amide (VIIb).Acidolysis ofX, with liquid hydrogen fluoride, gave crude LHRH (XI). Purification afforded LHRH, which was chemically identical with the luteinizing hormone‐releasing hormone synthesized elsewhere by another method, and which was found to be

ISSN:0165-0513    

DOI:10.1002/recl.19760950607

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractThe synthesis of some cyclopropanes with a trimethylsilyloxy group and an aryl group carrying electron‐donating substituents at the same ring carbon atom is described. These compounds can be used as precursors for 1‐aryl‐cyclopropanols and ‐cyclopropyl ch

ISSN:0165-0513    

DOI:10.1002/recl.19760950608

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

摘要:

Abstract2,5‐Dihydrothiophene can be obtained in reasonable yield by reaction ofcis‐1,4‐dichloro‐2‐butene with anhydrous sodium sulfide in a mixture of methanol and dimethyl sulfoxide. The contaminating 3,4‐epithio‐1‐butene can be removed by reaction with excess of Na2S. 3,4‐Epithio‐1‐butene and 3,6‐dihydro‐1,2‐dithiin have been obtained in good yields by treatingtrans‐1,4‐dibromo‐2‐butene andcis‐1,2‐dichloro‐2

ISSN:0165-0513    

DOI:10.1002/recl.19760950609

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractA number of synthetic routes to fully aromatic bisketenimines, versatile additives for processing polyethylene terephthalate into high‐performance tyre yarns, have been studied. A convenient procedure is presented here: conversion of a bis‐gem‐dichloroaziridine with sodium iodide or

ISSN:0165-0513    

DOI:10.1002/recl.19760950610

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19760950601

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY