Trifluoroacetic acid → benzyl 2-[3-chloro-2-methyl-5-(3-[(methylamino)methyl]phenethylamino)-6-oxo-1(6H)-pyrazinyl]acetate

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Reaction Steps

Benzyl-2-[3-[(3-[(tert-butoxycarbonyl)(methyl)amino]methylphenethyl)amino]-5-chloro-6-methyl-2-oxo-1(2H)-pyrazinyl]acetate (preparation 18) (0.7 g, 1.26 mmol) was dissolved in CH2Cl2 (10 ml) and treated with TFA (1.0 ml). After stirring at room temperature for 3 hr, the reaction mixture was evaporated to dryness then dissolved in ethyl acetate (200 ml) washed with sat. aq NaHCO3, sat aq brine, dried over MgSO4. Removal of the drying agent by filtration followed by evaporation of the solvent gave a dark brown oil which was purified by chromatography (SiO2, gradient elution with 100% CH2Cl2; 98:2 CH2Cl2:MeOH; 95:5 CH2Cl2:MeOH; 95:5:1 CH2Cl2:MeOH:NH3) to give the desired product (0.38 g, 65%). 1H NMR (CDCl3) δ 2.00 (s, br, 1H), 2.20 (s, 3H), 2.45 (s, 3H), 2.90 (t, 2H), 3.70 (m, 2H), 3.75 (s, 2H), 4.80 (s, 2H), 5.20 (s, 2H), 6.10 (m, br, 1H), 7.10 (m, 1H), 7.15 (m, 2H), 7.25 (m, 1H), 7.35 (m, 5H). LRMS m/z=455.0, 457.2 (M+1)+.

Provenance & Evidence