An efficient process for the M1-selective muscarinic agonist MCD-386 has been developed that offers significant advantages over the original synthetic approach. The new process utilizes an improved preparation of a known sym. diamine ester, followed by elaboration to a sym. 5-substituted tetrahydropyrimidine. The new route avoids cryogenics and chromatog. steps, circumvents an expensive protecting group strategy, and offers significant improvements in cost and throughput.