Alkylation of 3-Ethoxy-2-Lithioacrylonitrile: Synthesis of 5-Alkylcytosines

Abstract
The utility of commercially available, inexpensive 3-ethoxyacrylonitrile (1) as a precursor for the synthesis of 5-alkylcytosines was investigated. Metalation of 1 affords a 2-lithio derivative of sufficient stability to allow alkylation with allylic or benzylic bromides and primary iodides which are unbranched at the β-position. The alkylated derivatives are converted to 5-alkylcytosines in modest yield by exposure to sodium ethoxide and urea in ethanol.