With ButNH2 the anhydride R(PhNH)P(O)OS18O2Bn 5 (R = But), like the hydroxylamine derivative R(Ph)P(O)NHOS18O2Bn 4 (R = PhMeCH), gives ButNHS18O2Bn containing only a part (76–78%) of the available 18O label; this is a result of partial scrambling of the label in 5 (OS18O2
⇌
18OSO2) while it is reacting; there is no need to postulate scrambling in the rearrangement of 4 to 5 (R = PhMeCH) or to exclude a concerted mechanism.
与
羟胺衍
生物R(Ph)P(O)NHOS18O2Bn 4(R = PhMeCH)一样,酸酐R(PhNH)P(O)OS18O2Bn 5(R = But)在ButNH2中仅含有部分(76-78%)可用的18O标记;这是由于5(OS18O2 ⇌ 18OSO2)在反应时部分标记混乱的结果;没有必要假设4到5(R = PhMeCH)的重排混乱,也不必排除协同机制。