157562-24-8Relevant articles and documents
HAMMICK CYCLIZATIONS STUDIES ON THE MECHANISM OF THE HAMMICK REACTION
Bohn, Bernhard,Heinrich, Nicolaus,Vorbrueggen, Helmut
, p. 1731 - 1746 (2007/10/02)
Heating of 3-hydroxypicolinic acid with the acetylketene precursor 2,2,4-trimethyldioxin-4-one, ethyl acetoacetate or ethyl 2-cyclopentaneonecarboxylate leads via the 3-O-acylated 3-hydroxypicolinic acids, which cannot be isolated, and subsequent decarboxylation to the corresponding Hammick cyclization products in up to 25 percent yields besides 3-hydroxypyridine.In the case of 3-aminopicolinic acid the 3-(3-oxobutyrylamido)picolinic acid can be isolated but gives on heating only 3-aminopyridine and 3-(3-oxobutyrylamido)pyridine albeit none of the anticipated Hammick cyclization products.The Hammick cyclization reactions, side reactions and reaction mechanisms are discussed.