作者:Alan A. Katritzky、Sergei A. Belyakov、Dai Cheng、H. Dupont Durst
DOI:10.1055/s-1995-3958
日期:1995.5
Several 1,3,5-triarylformazans were synthesized (42-77%) using a new methodology. Azo-coupling of aryldiazonium salts with arylaldehyde arylhydrazones under mild basic conditions in two-phase liquid-liquid media is efficiently promoted by phase-transfer catalysts (onium salts or dicyclohexano-18-crown-6) at 5-25°C. The condensation of benzaldehyde with phenylhydrazine followed by phase-transfer catalyzed azo-coupling with phenyldiazonium chloride (one-pot procedure) gave 1,3,5-triphenylformazan in a 54% yield without isolation of the intermediate benzaldehyde phenylhydrazone. A double azo-coupling reaction of phenyldiazonium chloride with 9 different CH-active compounds afforded corresponding formazan only in the case of phenylpyruvic acid. Reaction in malonamide gave 3-carbamoyl-1,5-diphenylformazan instead of the expected 1,5-diphenylformazan.
采用一种新方法合成了多种 1,3,5-三芳基甲臢(42-77%)。相转移催化剂(鎓盐或二环己烷-18-冠醚-6)可在 5-25°C 的温度下,在两相液液介质的温和碱性条件下有效促进芳基偶氮盐与芳基醛芳基肼的偶氮偶联反应。苯甲醛与苯肼发生缩合反应,然后在相转移催化下与苯基重氮氯化物发生偶氮偶联反应(一锅法),得到 1,3,5-三苯基甲酰肼,收率为 54%,且无需分离中间体苯甲醛苯腙。苯基重氮酰氯与 9 种不同的 CH 活性化合物进行双偶氮偶联反应,只有苯基丙酮酸能得到相应的甲臢。在丙二酰胺中反应得到的是 3-氨基甲酰基-1,5-二苯基甲臢,而不是预期的 1,5-二苯基甲臢。