tert-Butyl 4-(2-oxo-1,2,3,4-tetrahydroquinazolin-7-yl)-5,6-dihydropyridine-1(2H)-carboxylate → tert-Butyl 4-(2-oxo-1,2,3,4-tetrahydroquinazolin-7-yl)piperidine-1-carboxylate

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Reaction Steps

To a solution of compound 22 (0.8 g, 2.45 mmol) in THF (20 mL) was added Pd—C (10% wet basis, 0.15 g), and the mixture was subjected to hydrogenation in a Parr apparatus at 60 psi for 12 h. After filtering over the pad of celite, the solution was concentrated to get a brown oil material, which was resolved over silica column, eluting with hexanes:ethyl acetate (4:6) and then changing to (6:4) yielded 0.59 g (76%) of 23 as a light yellow gum. IR (KBr) νmax. cm−1: 3211, 3165 (NH), 3072 (Ar—H), 1698 (C═O), 1610, 1512, 1419 (C═C). 1H-NMR (500 MHz, CDCl3) δ=1.48 (s, 9H, (CH3)3C); 1.54 (m, 2H, CH2); 1.75-1.82 (m, 2H, CH2); 2.56 (m, 1H, CH); 2.76 (br. s, 2H, CH2); 4.23 (br. s, 2H, CH2); 4.44 (s, 2H, CH2); 6.58 (m, 2H, H-7, H-8); 7.30 (m, 1H, d, J=8.3 Hz, H-5); 13C NMR (125.7 MHz, CDCl3) δ=28.38 (CH3)3C), 32.50 (CH2), 42.87 (CH2), 43.30 (CH), 47.88 (CH2), 66.36 (CH2), 79.53 (CH3)3C), 93.98 (aromatic-C), 113.24 (aromatic-C), 116.97 (aromatic-C), 117.68 (aromatic-C), 132.41 (aromatic-C), 134.49 (aromatic-C), 149.82 (aromatic-C), 152.48 (C═O), 154.69 (C═O). Calculated (%) for C18H25N3O3(331.19); C, 65.23; H, 7.60; N, 12.68. found (%); C, 65.12; H, 7.69; N, 12.55.

Provenance & Evidence