Reaction Steps
A 4-mL vial was charged with salicylate 16 (0.0075 g, 0.01 mmol, 1.0 equiv), and Pd(OH)2/C (20 wt. %, 0.005 g). MeOH (1 mL) was added and the vial was sealed with a Teflon cap. The atmosphere was replaced by H2 (balloon, ˜1 atm.) and stirred until TLC analysis indicated complete consumption of the starting material, typically 20 min. The resulting suspension was filtered through a pad of CELITE® 545 (diatomaceous earth, filter aid) and washed with MeOH. The homogeneous solution was concentrated in vacuo. The crude residue was purified by flash chromatography (98:2 CH2Cl2:MeOH) affording pactamycin (0.005 g, 82%) as a pale yellow solid. Analytical data: [α]D19+27.4 (c=0.40, CHCl3); 1H NMR (600 MHz, CDCl3): δ 10.98 Or s, 1H), 7.91 (d, J=10.8 Hz, 1H), 7.26-7.23 (m, 4H), 7.18-7.16 (m, 2H), 6.81-6.78 (m, 2H), 6.64 (d, J=7.2 Hz, 1H), 5.78 (br s, 1H), 5.67 (d, J=10.8 Hz, 1H), 4.84 and 4.79 (ABq, J=12.6 Hz, 2H), 3.93 (m, 1H), 3.80 (d, J=10.2 Hz, 1H), 2.99 (s, 6H), 2.95 (s, 1H), 2.55 (s, 3H), 2.38 (s, 3H), 1.55 (s, 3H), 1.04 (d, J=6.0 Hz, 3H); 13C NMR (150 MHz, CDCl3): δ 198.5, 172.6, 162.8, 159.2, 146.6, 141.2, 138.3, 134.6, 129.6, 123.0, 118.7, 118.4, 115.7, 112.0, 110.8, 88.8, 84.9, 74.3, 71.5, 68.7, 65.4, 63.2, 36.9, 29.7, 26.7, 24.1, 21.1, 18.1; HRMS (ESI1) Calcd. for C28H38N4O8+H, 559.2762. Found, 559.2763. IR (thin film, cm−1) 3393, 2938, 2359, 2341, 1698, 1652, 1520, 1473, 1418, 1338, 873, 668; TLC (95:5 CH2Cl2/MeOH): Rf=0.30.
