Ultrasonic-Assisted Synthesis of Two t -Butoxycarbonylamino Cephalosporin Intermediates on SiO2

Herein,we describe a facile and high efficient strategy for the synthesis of two forms of the 7β-t-butoxycarbonylamino-3-chloromethyl-3-cephem-4-carboxylates using ultrasonic irradiation. by sio2 as weak lewis acid catalyst,4-methoxybenzyl 7β-t-butoxycarbonylamino-3-chloromethyl-3-cephem-carboxylate (boc-acle) and benzhydryl 7β-t-butoxycarbonylamino-3-chloromethyl-3-cephem-4-carboxylate (boc-aclh) were successfully synthesized through the efficient protection of the n-t-butoxycarbonyl (n-boc),and the reactions occurred at low temperature requiring short reaction times and exhibiting excellent isolated yields (96% and 96.2%,resp.). the advantages of this reaction route including the usage of economical reagents and mild reaction conditions and high isolated yield make the two significant t-butoxycarbonylamino cephalosporin intermediates possible in large-scale production. � 2016 feng xue et al.