Synthesis of N-(substituted phenylcarbonylamino)-4-ethyl-1,2,3,6-tetrahydropyridines as potential nonsteroidal anti-inflammatory agents

Fourteen novel N-(substituted phenylcarbonylamino)-4-ethyl-1,2,3,6-tetrahydropyridines 9 were synthesized in fair to good yields. 4-Ethylpyridine 5 reacted with O-mesitylenesulfonylhydroxylamine (O-MSH) 4 to furnish N-amino-4-ethylpyridinium mesitylenesulfonate 6. The reaction of 6 with substituted acid chlorides 7 gave the stable crystalline pyridinium ylides 8a-8n. A sodium borohydride reduction of 8 in absolute ethanol furnished the target compounds N-(substituted phenylcarbonylamino)-4-ethyl-1,2,3,6-tetrahydropyridines 9a-9n.