METHODS Pemetrexed was synthesized starting from p-iodobenzoic acid via ten steps,including chlorination,esterification,condensation,cyclization,hydrolysis and saponification.

• 方法以对碘苯甲酸为起始原料,经氯化、酯化、缩合、环合、水解、成盐等十步反应合成培美曲塞。