Acetic Acid → tert-Butyl 4-[N-[-2-Acetoxymethyl-4-oxo-3-pivaloyloxymethyl-3,4,7,8-tetrahydro-6H-cyclopenta[g]quinazolin-6-yl]-N-methylamino]benzoate

Participants

Reaction Steps

To a stirred solution of tert-butyl 4-[N-[-2-acetoxymethyl-4-oxo-3-pivaloyloxymethyl-3,4,7,8-tetrahydro-6H-cyclopenta[g]quinazolin-6-yl]amino]benzoate (0.060 g, 0.106 mmol) in THF (6 ml) was added glacial acetic acid (2 ml) followed by 37% aqueous formaldehyde (0.090 ml). The solution was stirred for 2.5 hours at room temperature and then sodium cyanoborohydride (0.017 g, 0.27 mmol) was added. The reaction mixture was stirred overnight at room temperature. The solvent was removed in vacuo and the residue was partitioned between ethyl acetate (25 ml) and water (25 ml). The aqueous layer was extracted with more ethyl acetate (2×25 ml). The combined organics were washed with saturated aqueous sodium bicarbonate (30 ml), brine (30 ml), dried (Na2SO4) and concentrated in vacuo to leave an oil (0.060 g, 98%); 1H-NMR (CDCl3) 1.20 (s, 9H, POM C(CH3)3), 1.58 (s, 9H, CO2C(CH3)3), 2.15 (s, 3H, CH3CO), 2.02, 2.52 (2×m, 2H, 7-CH2), 2.74 (s, 3H, N10-Me), 3.13 (m, 2H, 8-CH2) 5.21 (s, 2H, 2-CH2), 5.66 (t, 1H, J=8.1 Hz, 6-H), 6.12 (AB system, J=10.8 Hz, 2H, POM CH2), 6.85 (d, J=8.8 Hz, 2H, 3,5′-ArH), 7.58 (s, 1H, 9-H), 7.90 (d, J=8.9 Hz, 2H, 2,6′-ArH), 8.08 (s, 1H, 5-H); MS (ESI, m/z) 578 (M+H)+.

Provenance & Evidence