Phase Transfer Catalysis: Reaction of 4-Bromopyridine with Cyclic Secondary Amines

Abstract

Our interest in the acylation of alcohols lead us to investigate the use of substituted amino-pyridines as catalyst¹ for the acylation reaction. Since a literature search^2–5 revealed that the available procedures required the use of expensive starting materials, high temperatures, and long reaction times to obtain moderate yields of product, we investigated the applicability of phase transfer catalysis to the alkylation of several cyclic secondary amines with halopyridines. Although the alkylation of hydroxyl, thiol and amino groups using phase transfer catalyst⁶ is not unique, there are few examples available of the alkylation of amino groups by halogenated aromatics. We report here the alkylation of several secondary cyclic amines with 4-bromopyridine hydrochloride employing benzyltriethylammonium bromide as the phase transfer catalyst. The resulting crystalline products are powerful catalyst for the acylation of cholesterol and of