The chrysanthemumcarboxylic acids. II.—-Esterification of the chrysanthemic acids
作者:S. H. Harper、H. W. B. Reed
DOI:10.1002/jsfa.2740020908
日期:1951.9
Esterification of (±)-cis- and (±)trans-chrysanthemic acids in methanolic sulphuric acid gives the expected methyl chrysanthemates together with methyl δ-methoxydihydro-chrysanthemates. Normal esterification of the carboxyl group is accompanied, in part, by acid-catalysed addition of methanol to the ethylenic bond of the isobutenyl group. Methyl (±)-cis-δ-methoxydihydrochrysanthemate is also formed
(±)-cis- 和 (±)trans-菊酸在甲醇硫酸中的酯化得到预期的菊花酸甲酯和 δ-甲氧基二氢菊酸甲酯。羧基的正常酯化部分伴随着酸催化的甲醇加成到异丁烯基的烯键上。(±)-顺式-δ-甲氧基二氢菊酸甲酯也可在 (±)-顺式-二氢-菊花-δ-内酯的甲醇分解作用下形成。菊酸甲酯的臭氧化,然后是臭氧化物的氢解,以低产率得到(±)-顺式-和(±)-反式-3-甲酰基-2:2-二甲基环丙烷-I-羧酸甲酯。(±)-反式-醛基酯也可通过 (±)-反式-3-碳甲氧基-2 的罗森蒙德还原获得,但产率也很低: