New ?-o-(5-oxopyrazol-3-yl)arylethylamines and their unusual metastable betaine form

摘要

Novel 13-arylethylamines bearing 5-pyrazolone substituent in the ortho-position of aryl moiety were obtained by the hydrazine-induced recyclization of 1-(alkoxycarbonyl-methylidene)-1,2,3,4-tetrahydroisoquinolines. These amines can exist in a highly unstable betaine form in the solid phase.