Tris(furan-2-yl)phosphane → 7-Benzyl-4-(pyridin-2-yl)-5,6,7,8-tetrahydropyrido[3,4-d]pyrimidine

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Reaction Steps

Part C: To a solution of 7-benzyl-4-chloro-5,6,7,8-tetrahydropyrido[3,4-d]pyrimidine (4.75 g, 18.3 mmol) in 1,4-dioxane (80 mL) at 25° C. was added sequentially 2-(tributylstannyl)pyridine (98%, 5.95 mL, 18.3 mmol), tri-2-furylphosphine (0.85 g, 3.66 mmol), and palladium (II) acetate (0.205 g, 0.914 mmol). The resulting mixture was heated slowly to reflux over ˜0.25 h and then was stirred at reflux for 5.0 h. After cooling to room temperature the mixture was diluted with water and ethyl acetate, and the mixture filtered. The phases were separated, and the organic phase washed with water and brine, dried over anhyd. sodium sulfate, filtered, and concentrated. Column chromatography (elution: 0-5% 2M ammonia in methanol/chloroform) afforded 7-benzyl-4-(pyridin-2-yl)-5,6,7,8-tetrahydropyrido[3,4-d]pyrimidine (2.15 g, 39%) as a red oil; Mass Spec.: m/c: 303.15 (M+H)+ [calc'd: 303.15]; 1H NMR (500 MHz, CDCl3) δ 9.02 (s, 1H), 8.68 (m, 1H), 8.01 (m, 1H), 7.83 (m, 1H), 7.42-7.27 (m, 6H), 3.80 (m, 4H), 3.31 (m, 2H), 2.80 (m, 2H).

Provenance & Evidence