[H-].[Na+].[NH:3]1[CH:7]=[CH:6][N:5]=[CH:4]1.Br[CH2:9][CH2:10][CH2:11][CH2:12][Cl:13].[C:14]([OH:17])(=[O:16])[CH3:15]>C1COCC1>[C:14]([OH:17])(=[O:16])[CH3:15].[Cl:13][CH2:12][CH2:11][CH2:10][CH2:9][N:3]1[CH:7]=[CH:6][N:5]=[CH:4]1To a suspension of NaH (1.11 g; 46.3 mmol) in dry THF, imidazole (3 g; 44.1 mmol) dissolved in 15 ml dry THF is added drop-wise at RT. After completion of the addition the mixture is refluxed for 1 h. After cooling to RT 1-bromo-4-chloro-butane (15.2 ml; 132 mmol) is added and the reaction is stirred for 16 h at RT. The mixture is acidified with acetic acid, filtered and evaporated. The residue is taken-up in hydrochloric acid (10%, 80 ml) and extracted with EtOAc (2×20 ml). The aqueous layer is adjusted to pH 8 with carbonate buffer and the product is extracted with Et2O. After addition of 1 eq AcOH the organic layer is dried over MgSO4 and concentrated in vacuo to give the compound (6.78 g).
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