Process for the preparation of N-vinylated unsaturated nitrogen-containing five-membered heterocycles

摘要

1. Process for the preparation of N-vinylated unsaturated five-membered N-heterocyclic compounds of the formula see diagramm : EP0150380,P6,F3 wherein A, B and C can be identical or different and can represent N, C-H, C-Hal, C-alkyl or C-phenyl, with the proviso that A, B and C represent a maximum of 2 further N atoms in the five-membered ring, and D can represent C-H, C-Hal, C-alkyl or C-phenyl, or A and B, or C and D, where A, B and C do not represent N, can be the constituent of a benzene ring, which is optionally substituted by fluorine, chlorine, bromine, a nitro or trihalogenomethyl group, an alkoxy group with 1 to 4 carbon atoms, a carbalkoxy group with 1 to 4 carbon atoms or a dialkylamino group with 1 to 4 carbon atoms, characterised in that N-beta-hydroxyethyl-N-heterocyclic compounds of the general formula see diagramm : EP0150380,P6,F4 wherein A, B, C and D have the abovementioned meaning, are reacted with carbonic acid esters of the formula see diagramm : EP0150380,P6,F5 wherein R**1 and R**2 are identical or different and represent an alkyl radical with 1 to 4 carbon atoms, at temperatures in the range from 100 to 250 degrees C, the resulting carbonate is heated under a reduced pressure of 0.01 to 300 mbar to temperatures of 100 to 270 degrees C and the reaction product is then separated off by distillation.