中文名称 | 英文名称 | CAS号 | 化学式 | 分子量 |
---|---|---|---|---|
乙酰氨基丙二酸二乙酯 | 2-acetylaminomalonic acid diethyl ester | 1068-90-2 | C9H15NO5 | 217.222 |
N-乙酰基-DL-丝氨酸 | N-acetyl-serine | 97-14-3 | C5H9NO4 | 147.131 |
—— | acetylamino-hydroxymethyl-malonic acid diethyl ester | 6267-40-9 | C10H17NO6 | 247.248 |
The biomimetic oxidative coupling of the ethyl ester of N-acetyl-3,5-diiodotyrosine (1) to yield the ethyl ester of N-acetylthyroxine (2) has been investigated. A putative mechanism involving phenolic coupling to yield an intermediate aryloxydienone (7) followed by an E2 elimination for loss of the side chain has been proposed. Oxidative couplings with analogous 4-substituted 3,5-diiodophenols indicate that a number of mechanisms are possible; these include quinone methide intermediates and SN2 substitutions in the intermediate aryloxydienones. Rearomatization of the intermediate aryloxydienones is a strong driving force for the loss of the side chains. The results indicate that 3,5-diiodo-4-aryloxydienones are good leaving groups in E2 and SN2 mechanisms. The synthetic method provides a facile synthesis of thyroxine analogues from readily available 4-substituted 3,5-diiodophenols. Keywords: diiodotyrosine, phenolic coupling, phenoxyl radicals, thyroxine.