Design and Synthesis of Novel N-tert-butyl-N-substitutedbenzoyl-N- [dihydrobenzofuran(chroman)]carbohydrazide Derivatives as Potential Insect Growth Regulators
作者:Zhiqiang Huang、Qiqi Zhao、Runqiu Huang、Qingmin Wang
DOI:10.2174/157017809787003070
日期:2009.1.1
Six of new N-tert-butyl-N-substitutedbenzoyl-N-(2,4-dimethyl-2,3-dihydrobenzofuran)-7-carbohydrazide derivatives and five of new N-tert-butyl-N-substitutedbenzoyl-N-(5-methylchroman)-8-carbohydrazide derivatives were designed and synthesized from m-cresol. The synthesis highlighted that some kinds of reactions were ameliorated in methodology. An important feature is that 1-(3-allyl-2-hydroxy-4-methylphenyl)ethanone can easily be transformed into 1-(2,3-dihydro-2,4-dimethylbenzofuran-7-yl)ethanone just with concentrated sulfuric acid as catalyst. In addition, we found that 1-(5-methyl-2H-chromen-8-yl)ethanone could not be reduced to 1-(5-methylchroman-8-yl)ethanone directly by hydrogen with Pd/C as catalyst. It is an effective method for protecting 1-(5-methyl-2H-chromen-8-yl)ethanone with ethylene glycol to obtain 5-methyl-8-(2-methyl-1,3-dioxolan-2-yl)-2H-chromene and then reducing by hydrogen with Pd/C as catalyst to produce 1-(5-methylchroman-8-yl)ethanone in one step. Furthermore, SOCl2 can convert 2,3-dihydro-2,4- dimethylbenzofuran-7-carboxylic acid to 2,3-dihydro-2,4-dimethylbenzofuran-7-carbonyl chloride, but it is inefficient for transforming 5-methylchroman-8-carboxylic acid to the corresponding acyl chloride. Hence, different heterocycles on the benzene ring of benzoheterocyle moiety have influence on the reaction property of the corresponding acid.
以间甲酚为原料,设计并合成了6种新的N-叔丁基-N-取代苯甲酰基-N-(2,4-二甲基-2,3-二氢苯并呋喃)-7-甲酰肼衍生物和5种新的N-叔丁基-N-取代苯甲酰基-N-(5-甲基苯并吡喃)-8-甲酰肼衍生物。合成结果表明,某些类型的反应在方法上有所改进。其中一个重要特点是,只需用浓硫酸作催化剂,1-(3-烯丙基-2-羟基-4-甲基苯基)乙酮就能轻松转化为 1-(2,3-二氢-2,4-二甲基苯并呋喃-7-基)乙酮。此外,我们还发现 1-(5-甲基-2H-苯并吡喃-8-基)乙酮在 Pd/C 催化剂的作用下不能直接被氢气还原成 1-(5-甲基苯并吡喃-8-基)乙酮。用乙二醇保护 1-(5-甲基-2H-苯并吡喃-8-基)乙酮,得到 5-甲基-8-(2-甲基-1,3-二氧戊环-2-基)-2H-苯并吡喃,然后用氢气和 Pd/C 作催化剂还原,一步生成 1-(5-甲基苯并吡喃-8-基)乙酮,是一种有效的方法。此外,SOCl2 可将 2,3-二氢-2,4-二甲基苯并呋喃-7-羧酸转化为 2,3-二氢-2,4-二甲基苯并呋喃-7-甲酰氯,但将 5-甲基苯并二氢吡喃-8-羧酸转化为相应酰基氯的效率较低。因此,苯并杂环上的不同杂环会影响相应酸的反应性质。