Synthesis of Pentazocine

l u t i d i n e (a) A r c h e r a n d c o -w o r k e r s ' method ( b ) Kametani a n d c o -w o r k e r s ' method ( c ) Sumitomokagaku' s method 2-2 F r o m 1 -amino-3-methyl-3-pentene ( a ) Mannich r e a c t i o n (b) B i s c h l e r -N a p i e r a l s k i r e a c t i o n 2-3 F r o m a n amino a c i d 2-4 T h e i n t r o d u c t i o n of 3-methyl-2-butenyl g r o u p to t h e 1 , 2 , 3,4,5,6-hexahydro-2,6-methano-3-benzazocine n u c l e u s(a) Debenzylation of q u a t e r n a r y ammonium s a l t by c a t a l y t i c hydrogenation (b) Debenzylation of q u a t e r n a r y ammonium s a l t by thio- phenoxide anion ( c ) Hofmann degradation of q u a t e r n a r y ammonium s a l t s (d) Acylation of N-methyl d e r i v a t i v e and reduction 3. S t e r e o c h e m i s t r y of pentazocine and i t s intermediate 3 1 Optical resolution of pentazocine 3-2 Configuration of intermediates 4. Conclusion