Cesium carbonate → (S)-3-[6-(6-Methoxy-5-methyl-pyridin-3-yl)-5,6,7,8-tetrahydro-pyrido[4,3-d]pyrimidin-4-yloxy]-pyrrolidine-1-carboxylic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

X-Phos (0.96 g, 2.01 mmol, 0.3 eq.), Pd2(dba)3 (0.615 g, 0.672 mmol, 0.1 eq.), Cs2CO3 (4.38 g, 13.44 mmol, 2 eq.) were combined and flushed 10 min with Argon. To this mixture, a solution of (S)-3-(5,6,7,8-tetrahydro-pyrido[4,3-d]pyrimidin-4-yloxy)-pyrrolidine-1-carboxylic acid tert-butyl ester (intermediate 7) (2.15 g, 6.72 mmol) in dioxane (6 mL) and 5-bromo-2-methoxy-3-methylpyridine (1.76 g, 8.73 mmol) were added at rt and the reaction mixture was stirred at 120° C. for 2 h. The reaction was cooled down to rt, the reaction mixture filtered over Hyflo, AcOEt was added and the organic layer was washed with brine, dried over Na2SO4, filtered and concentrated under vacuum. The residue was dissolved in dioxane (6 mL) and added to a glass vial containing 5-bromo-2-methoxy-3-methylpyridine (1.76 g, 8.73 mmol), X-Phos (0.96 g, 2.01 mmol), Pd2(dba)3 (0.615 g, 0.672 mmol), Cs2CO3 (4.38 g, 13.44 mmol). The vial was capped and the reaction mixture was stirred at 120° C. for 2 h. The reaction was cooled down to rt, the reaction mixture filtered over Hyflo, AcOEt was added and the organic layer was washed with brine, dried over Na2SO4, filtered and concentrated under vacuum. Purification by flash chromatography on silica gel (CH2Cl2 then TBME then TBME/MeOH 99/1 to 90/10) gave (S)-3-[6-(6-methoxy-5-methyl-pyridin-3-yl)-5,6,7,8-tetrahydro-pyrido[4,3-d]pyrimidin-4-yloxy]-pyrrolidine-1-carboxylic acid tert-butyl ester as a yellow foam (2.05 g, 69% yield). 1H NMR (400 MHz, DMSO-d6, 298K) δ ppm 1.35-1.44 (br.s., 9H) 2.07-2.23 (m, 2 H), 2.14 (s, 3 H), 2.87-2.93 (m, 2 H), 3.39-3.68 (m, 6 H), 3.81 (s, 3 H), 4.03-4.08 (m, 2 H), 5.56-5.63 (m, 1 H), 7.41-7.46 (m, 1 H), 7.67-7.73 (m, 1 H), 8.60 (s, 1 H). LCMS: [M+H]+=342.2, Rt(2)=0.94 min.

Provenance & Evidence