Synthesis of pyrrolo[2,3-d]pyrimidines via cyclocondensation of β-alkoxy- and β-amino-α-bromoaldehydes

A series of β-alkoxy- and β-amino-α-bromoaldehydes was synthesized. The cyclocondensation of these intermediates with 2,4-diamino-6-hydroxypyrimidine yielded a series of pyrrolo[2,3-d]pyrimidines containing heteroatoms in the side chain. Choice of protecting group proved critical to the success of the bromination and cyclocondensation reactions. A number of oxygen and nitrogen protecting groups were examined and the results are described herein.