Formation of Pyridines

SCHEME 1.150 Formation of 2,4,6-trimethylpyridine from acetoxime and calcium carbide in aqueous KOH. 

SCHEME 1.151 Formation of 6-methyl-l,2,3,4,7,8,9,10-octahydrophenanthridine from cyclohexanone oxime and acetylene in aqueous KOH. 

Reaction is carried out at 200°C-220°C in autoclave for 8 h, the maximum pressure reached during the synthesis being 27 atm. When calcium carbide is used, the yields of pyridines do not exceed 10%, while with pure acetylene, their values attain 30%. 

Apparently, for ketoximes and acetylene in aqueous-alkaline medium, the following condensation processes leading to pyridines are possible  

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Three-Membered Ring—Aziridines 164 5.1 Formation of Pyridine Ring 5.2 Formation of Pyrimidine Ring 176 178... 

Formation of Pyridines, Pyrroles, A -Bipyrrolines, Siloles, and (Z, Z)-Dienylsilanes Remarkable E ect of Substitution Patterns on the Butadienyl Skeletons... 

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