Hydrochloric Acid → (R)-4-chloro-5-methyl-5,6-dihydropyrido[2,3-d]pyrimidin-7(8H)-one

Participants

Reaction Conditions

Reaction Steps

Add (R)-tert-Butyl 4-chloro-5-methyl-7-oxo-6,7-dihydropyrido[2,3-d]pyrimidine-8(5H)-carboxylate (36 g, 1.0 equiv) to water (120 mL) and stir to form a suspension. Add 12N HCl (120 g, 10 equiv) drop wise at 20-30° C. and stir the mixture for 6-8 h. A solution gradually forms. Cool the solution to 5-10° C. and add concentrated ammonium hydroxide (86.4 g, 2.4 equiv) to form a suspension. Stir the suspension for 2-3 h and is filter. Wash the filter cake with cooled water (36 mL), and then slurry with cooled isopropanol (28 g). Filter the slurry and dry the filter cake in vacuo to yield (R)-4-chloro-5-methyl-5,6-dihydropyrido[2,3-d]pyrimidin-7(8H)-one (21 g, 87%). MS (ES) m/z=198 [M]+.

Provenance & Evidence