3-亚甲基异苯并呋喃-1(3H)-酮及其衍生物合成新方法

A Novel Synthetic Method of 3-Methyleneisobenfuran-1(3H)-one and Their Derivatives

报道了3-亚甲基异苯并呋喃-1(3H)-酮及其衍生物简易、高效的合成方法.其特点是原料易得且价格低廉、反应条件温和、收率高.该方法以2-甲基苯甲酸及其衍生物为原料,经过酯化、自由基溴代和三苯基膦发生亲核取代反应合成了2-[(溴三苯基正膦基)甲基]苯甲酸甲酯及其衍生物;随后发生Wittig反应、羧酸酯碱性条件下水解得到2-乙烯基苯甲酸及其衍生物;接着和碘(NBS)发生环合反应,生成3-碘(溴)甲基异苯并呋喃-1(3H)-酮及其衍生物;最后消除卤化氢得到目标化合物.

A novel and highly efficient synthesis of 3-methyleneisobenzofuran-1（3H）-one and the corresponding derivatives was reported. The new method was characterized with raw material easy to get, low manufacturing cost, mild reaction conditions and high yields. 2-Methylbenzoic acid and their derivatives were used as starting material, methyl 2-（（bromotri- phenylphosphoranyl）methyl）benzoate and their derivatives were synthesized through esterification, free-radical bromination with N-bromobutanimide（NBS） and nucleophilic substitution with triphenylphosphine. After Wittig reaction and hydrolysis of carboxylic esters, 2-vinylbenzoic acid and their derivatives were obtained. Then through cyclization reaction with iodine（NBS）, 3-iodo（bromo）methylisobenzofuran-1（3H）-one and their derivatives were obtained, which further react by elimination hydrogen halide with 1,8-diazabicyclo[5.4.0]under-7-ene to afford the target compounds. Eleven intermediates were new compounds.