N-丁氧羰基-4-溴丙氨酸 、
1,4-二溴丁烷 、
(4-bromo-butyl)-(4-bromo-phenyl)-carbamic acid tert-butyl ester 、
2-phenyl-4,5-dihydro-oxazole-4-carboxylic acid tert-butyl ester 、 、 以Jew et al., 2004, ibid) to provide 4-{4-[(4-bromo-phenyl)-tert-butoxycarbonyl-amino]-butyl}-2-phenyl-4, 5-dihydro-oxazole-4-carboxylic acid ethyl ester (XXIX)的产率得到4-{4-[(4-bromo-phenyl)-tert-butoxycarbonyl-amino]-butyl}-2-phenyl-4,5-dihydro-oxazole-4-carboxylic acid ethyl ester