Diisopropylethylamine → 6-Benzyl-N-((6-chloropyridin-3-yl)methyl)-5,6,7,8-tetrahydropyrido[4,3-d]pyrimidin-4-amine

A mixture of 6-benzyl-4-chloro-5,6,7,8-tetrahydropyrido[4,3-d]pyrimidine (2.5 g, 9.6 mmol), 2-chloro-5-aminomethylpyridine (2.7 g, 19 mmol), acetonitrile (10 mL), and N,N-diisopropylethylamine (3.4 mL, 19 mmol) was subjected to microwave irradiation at 180° C. for 2 h. After standing at rt overnight, the precipitated solids were collected by filtration and washed with cold acetonitrile (5 mL×2), and dried to yield a yellow powder (2.8 g, 77%).