37708-79-5

Upstream product

• 112578-57-1 2,6-diphenyl-4-piperidino-pyrylium; chloride 
• 42833-29-4 1-Methyl-4-piperidino-1,2,3,6-tetrahydropyridin 
• 99277-18-6 1,3-Diethoxy-1,3-diphenyl-2-azapropenylium tetrafluoroborate 
• 6177-17-9 1,5-diphenyl-penta-2,3-diene-1,5-dione 
• 102756-64-9 1,5-diphenyl-3-piperidino-pent-2ξ-ene-1,5-dione 

Relevant academic research and scientific papers

2,6-Disubstituted 4-Aminopyridines from 1,3-Dialkoxy-2-azapropenylium Salts and N-Methyl-4-piperidone Enamines

1,3-Dialkoxy-2-azapropenylium salts 1 react with enamines 2 of N-methyl-4-piperidone at room temperature to give 2,6-disubstituted 4-aminopyridines 4,5 in low to moderate yield after hydrolysis.Intermediates of the reaction of 1a with 2 are the bicyclic iminium salts 6 and 7, which may be detected (1)H-NMR spectroscopically prior to hydrolysis.Hydrolysis of the mixture obtained from the reaction of 1a with 2a under basic conditions furnishes the bicyclic ketone 3 as the major product.A "retro-Mannich"-type reaction is suggested to explain the degradation of the bicyclic intermediates 6, 7 with the formation of the pyridines 4, 5. - Key Words: 2-Azapropenylium salts, 1,3-dialkoxy- and 1,1,3,3-tetraalkoxy- / Enamines of N-methyl-4-piperidone / 4-Aminopyridines / 3,7-Diazabicyclonon-2-en-9-ones / Retro-Mannich reaction