This paper will outline the mechanism of the Bischler–Napieralski cyclodehydration for the radiosynthesis of (R)-(-)-[6a-14C]apomorphine 1. The carbon-14 radiosynthesis of (R)-(-)-[6a-14C]apomorphine was first reported by Kitson and Knagg in May 2006. The Bischler–Napieralski cyclodehydration of 3,4-dimethoxy-2-nitrophenyl-N-phenethyl[carboxyl-14C]acetamide 5 was initiated using a mixture of P2O5/POCl3 in refluxing toluene. This generated the endocyclic dehydration product 1-(3,4-dimethoxy-2-nitrobenzyl)dihydro[1-14C]isoquinoline 4. The Bischler–Napieralski endocyclic dehydration by-product was identified from 1H NMR and MS to be 3-(6,7-dimethoxyanthranil)-dihydro[1-14C]isoquinoline 7. The action of POCl3 in acetonitrile on 3,4-dimethoxy-2-nitrophenyl-N-phenethyl[carboxyl-14C]acetamide 5 gave exclusively the exocyclic dehydration product 1-(3,4-dimethoxy-2-nitrobenzal)-1,2,3,4-tetrahydro[1-14C]isoquinoline 8. Copyright © 2007 John Wiley & Sons, Ltd.
本文将概述Bischler-Napieralski环脱氢反应在(R)-(-)-[6a-14C]
阿朴吗啡1的放射性合成中的机理。2006年5月,Kitson和Knagg首次报道了(R)-(-)-[6a-14C]
阿朴吗啡的碳-14放射性合成。3,4-二甲氧基-2-
硝基苯基-N-苯乙基[羧基-14C]乙酰胺5的Bischler-Napieralski环脱氢反应是在回流
甲苯中用
P2O5/POCl3混合物进行的。由此产生了内环脱氢产物1-(3,4-二甲氧基-2-硝基苄基)二氢[1-14C]
异喹啉4。通过1H NMR和MS鉴定,Bischler-Napieralski内环脱氢副产物为3-(6,7-二甲氧基邻
氨基苯基)-二氢[1-14C]
异喹啉7。POCl3在
乙腈中对3,4-二甲氧基-2-
硝基苯基-N-苯乙基[羧基-14C]乙酰胺5的作用只产生了外环脱氢产物1-(3