Abstract
A convenient, concise route for the preparation of tetrahydropyrido[2,3-d]pyrimidines functionalized at the 5-position is presented starting from acyclic aldehydes. Key steps involve a high yielding Knoevenagel condensation, 1,4 conjugate addition with an allylcuprate and a pyrimidine annulation using guanidine hydrochloride. An improved synthesis of the starting aldehyde, ethyl 4-propalbenzoate is presented.