K 49 Kisil', S. P. New Fluoroaryl-containing beta,beta'-Dioxoesters in the Synthesis of Fluorobenzopyran-2(4)-ones [Electronic resource] / S. P. Kisil', Ya. V. Burgart, V. I. Saloutin // Russian Journal of Organic Chemistry (Translation of Zhurnal Organicheskoi Khimii). - 2001. - Vol. 37, № 10. - P1455-1462 Рубрики: ХИМИЧЕСКИЕ НАУКИ Аннотация: For the first time were obtained ethyl 2-(2-methoxy-3,4,5,6-tetrafluorobenzoyl)-3-oxobutanoate and ethyl 2-pentafluorobenzoyl-3-oxobutanoate and their copper chelates. The compounds were prepared by acylation of ethyl acetoacetate with 2-methoxy-3,4,5,6-tetrafluoro- and pentafluorobenzoyl chlorides. Cyclization of these ,'-dioxoesters afforded substituted chromones. 2-Methyl-5-methoxy-6,7,8-trifluoro-3-ethoxycarbonylchromone hydrolyzes depending on reaction conditions either to 5-hydroxy-2-methyl-6,7,8-trifluorochromone or to 5-hydroxy-2-methyl-6,7,8-trifluorochromone-3-carboxylic acid. Reaction with morpholine provided 7-substituted product, and with aqueous ammonia as a result of rearrangement forms 3-acetimidoyl-4-hydroxy-5-methoxy-6,7,8-trifluorocoumarin. Hydrolysis of the latter yields 3-acetyl-4-hydroxy-5-methoxy-6,7,8-triflu \\\\Expert2\\nbo\\Russian Journal of Organic Chemistry\\2001, 37 (10), 1455.pdf |