described. The first step involves a Stobbe condensation of benzaldehydes 9–11 with dimethyl succinate. Subsequent transposition of the ester and reduction of the double bond provides the building blocks 15–17 for an intramolecular Friedel–Crafts acylation. ABC-lactones 22–25 are prepared from γ-keto esters 18–21 by saponification, subsequent reduction with sodium borohydride followed by acid-catalyzed
发芽兴奋剂GR24(用于合成高效和高产制备5)及其A-环二甲基取代的类似物30 - 32已经描述。第一步包括
苯甲醛的斯滔布缩合9 - 11与
琥珀酸二甲酯。双键的酯和减少随后的换位提供积木15 - 17为分子内Friedel-Crafts酰化。ABC内酯22 – 25是由γ-
酮酸酯18 – 21制备的通过皂化,随后用
硼氢化钠还原,然后酸催化的内酯化。内酯与D环的偶联是通过甲酰化和随后用
溴代
丁烯内酯8进行处理而得到GR24及其二甲基类似物来实现的。用Striga hermonthica种子进行的
生物测定表明,二甲基类似物的活性略低于GR24本身。