C(O[C:4]([C:6]1[N:7]=[CH:8][C:9]2[C:14]([C:15]=1[OH:16])=[CH:13][CH:12]=[C:11]([NH:17][C:18]([NH:20][C:21]1[CH:26]=[CH:25][CH:24]=[CH:23][CH:22]=1)=[O:19])[CH:10]=2)=[O:5])C.[CH2:27]([C:30]([OH:32])=[O:31])[CH2:28][NH2:29].C[O-].[Na+].CO>>[OH:16][C:15]1[C:14]2[C:9](=[CH:10][C:11]([NH:17][C:18]([NH:20][C:21]3[CH:26]=[CH:25][CH:24]=[CH:23][CH:22]=3)=[O:19])=[CH:12][CH:13]=2)[CH:8]=[N:7][C:6]=1[C:4]([NH:29][CH2:28][CH2:27][C:30]([OH:32])=[O:31])=[O:5]4-Hydroxy-7-(3-phenyl-ureido)-isoquinoline-3-carboxylic acid ethyl ester (75 mg, 0.2135 mmol) and B-alanine (191 mg, 2.135 mmol) were combined in a dry flask. 0.5M sodium methoxide in methanol (4.2 mL, 2.135 mmol) was added with stirring and the solution brought to reflux and held for 24 h. The mixture was cooled, concentrated in vacuo and the residue dissolved in water. The solution was acidified to pH 3 with 1M hydrochloric acid and the precipitate isolated by filtration. The crude product was purified by trituration with a minimal volume of methanol to provide the title compound in 57% yield. MS ESI(+) m/e: 395.1345 (M+1).
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