Cl[C:2]1[CH:11]=[CH:10][C:5]([C:6]([O:8][CH3:9])=[O:7])=[CH:4][N:3]=1.[NH:12]1[CH:16]=[CH:15][N:14]=[CH:13]1.[Na].[H-].[Na+].N1C=CN=C1>CN(C=O)C>[N:12]1([C:2]2[CH:11]=[CH:10][C:5]([C:6]([O:8][CH3:9])=[O:7])=[CH:4][N:3]=2)[CH:16]=[CH:15][N:14]=[CH:13]1A solution of the methyl ester obtained in Step 1. above (16.29 g) in DMF is added dropwise to a DMF suspension of sodium imidazole [prepared from NaH (4.19 g) and imidazole 6.49 g)] at RT. The reaction mixture is heated to 120° C. for nineteen hours. The cooled reaction mixture is partitioned between water and chloroform, the organic layer separated, washed with water, dried over Na2SO4, filtered, evaporated, and residual DMF removed under high vacuum yielding the desired product as a tan solid which is recrystalized from methanol (M.P. 183°-184.5° C.) before use in the next step.
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