[C:1]([C:4]1[C:5]([N+:20]([O-])=O)=[C:6]([O:18][CH3:19])[C:7]([C:15](=[O:17])[NH2:16])=[C:8]([N+:12]([O-])=O)[C:9]=1[O:10][CH3:11])(=[O:3])[NH2:2].CO.Cl>[Pd].C(O)CCC.C(O)(=O)C.O>[C:15]([C:7]1[C:8]([NH2:12])=[C:9]([O:10][CH3:11])[C:4]([C:1](=[O:3])[NH2:2])=[C:5]([NH2:20])[C:6]=1[O:18][CH3:19])(=[O:17])[NH2:16]A mixture consisting of 561 mg (1.79 mmol) of 6, 50 mg of 5% Pd/C, and 100 mL of methanol was shaken under 50 psi of H2 for 4 hours. Upon completing the reduction, 10 mL of concentrated hydrochloric acid was added immediately to the reaction mixture with stirring. After filtering the acidified mixture through CELITE and washing with methanol, the solvents were evaporated in vacuo and the solid residue thoroughly dried. The 8·2HCl was purified by dissolution in a minimum amount of hot methanol followed by addition of ethyl acetate: 568 mg (97%) yield; TLC (n-butanol/acetic acid/water [5:2:3]), Rf =0.37; 1H NMR (dimethyl-d6 sulfoxide) δ7.93 and 7.92 (4H, 2 brs, 3- and 6-carbamyls, no assignments made), 3.69 (6H, s, methoxys); mass spectrum (EI mode), m/z 254 (P+).
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