[(3S,5S)-3-(2-Methyl-allyl)-2-oxo-5-phenyl-morpholine-4-carbothioyl]-carbamic acid benzyl ester 在
N-溴代丁二酰亚胺(NBS) 作用下,
以
二氯甲烷 为溶剂,
以91%的产率得到(4S,8R,9aS)-8-Bromomethyl-8-methyl-1-oxo-4-phenyl-6-thioxo-hexahydro-pyrimido[6,1-c][1,4]oxazine-7-carboxylic acid benzyl ester