Efficient Synthesis of 6-Amino-Substituted Pyridin-2(1H)-ones Using in situ Generated Propiolic Acid Chloride

Abstract

A regioselective and highly efficient synthesis of 6-amino-substituted pyridin-2(1H)-ones is presented. In situ generated propiolic acid chloride was used for the cyclization of acyclic β-keto N,S-acetals to afford the heterocyclic core. Substitution by amines led to a flexible access of the target compounds.

Key words

pyridin-2(1H)-ones - cyclizations - thioacetals - N,S-acetals - ring closure

References

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2

From the cyclization of the ketene aminal comprising 1-cyclohexylmethanamine and cyclopropylamine (1, R = CH₂-cHex R′ = cPr) with propiolic acid methyl ester we isolated the regioisomeric compounds 3 and 3′ in 21% and 27% yield.