N-aryl-2-hydroxy-1,2,3,4-tetrahydropyridines and N-aryl-2-chloromethylene-1,2,3,4-tetrahydropyridines - Successive intermediates in the Hantzsch synthesis of 1,4-dihydropyridines

Article abstract of DOI:10.1007/BF02253029

Esters of 4-chloro-2-arylideneacetoacetic acid I and esters of N-arylaminocrotonic acid II form stable N-aryl-3,4-trans-2-hydroxy-1,2,3,4-tetrahydropyridines III. Their regio- and stereoselective dehydration results in N-aryl-2-chloromethylene-1,2,3,4-tetrahydropyridines with an exocyclic bond, IV. Compounds IV isomerize to the corresponding N-aryl-2-chloromethyl-1,4-dihydropyridines V in acid medium. Michael addition of compounds I and II in chloroform or benzene forms carbocyclic derivatives of cyclohexene VI. 1998 Plenum Publishing Corporation.