A process for the preparation of a compound of the general formula (III):
 wherein R¹, R², R⁵ and R⁶ each represent a hydrogen atom or an alkyl group containing from l to 4 carbon atoms, R is an alkyl group and X and Y each represent a hydrogen atom, a halogen atom or an alkyl, cycloalkyl, alkenyl, alkynyl, aryl, aralkyl, alkoxy or aryloxy group, the process comprising the elimination of the molecule HZ, with a simultaneous ring closure, from a compound of the general formula (IV):
 wherein R¹, R², R⁵ and R⁶ R, X and Y have the same meanings as before and Z is a leaving group, for example a chlorine or bromine atom or a tosylate or mesylate group.  
                            一种通式(III)化合物的制备方法:
 其中 R¹、R²、R⁵和 R⁶ 各自代表氢原子或含有 l 至 4 个碳原子的烷基,R 是烷基,X 和 Y 各自代表氢原子、卤素原子或烷基、环烷基、烯基、炔基、芳基、芳烷基、烷氧基或芳氧基,该过程包括从通式(IV)的化合物中消除分子 HZ,同时闭环:
 其中 R¹、R²、R⁵和 R⁶R、X 和 Y 的含义与前述相同,Z 为离去基团,例如
氯原子或
溴原子或甲
苯磺酸盐基团或
甲磺酸盐基团。