Bromine → 3-Methyl-2-(3-oxobenzo[d]isothiazol-2(3H)-yl)pentanoic acid
Reaction equation
C(C(NC([C:12]1[CH:36]=[CH:35][CH:34]=[CH:33][C:13]=1[C:14]([N:16]([S:25]SC1C=CC=CC=1)[CH:17]([CH:21]([CH3:24])[CH2:22][CH3:23])[C:18]([OH:20])=[O:19])=[O:15])=O)C(C)CC)(O)=O.BrBr>ClCCl>[CH3:24][CH:21]([CH2:22][CH3:23])[CH:17]([N:16]1[C:14](=[O:15])[C:13]2[CH:33]=[CH:34][CH:35]=[CH:36][C:12]=2[S:25]1)[C:18]([OH:20])=[O:19]Participants
4
Procedure
A stirred, room temperature suspension of 5.3 g (10.0 mmol) of [S-(R*,R*)]-2-[2-[2-(1-carboxy-2-methylbutylcarbamoyl)phenyldisulfanyl benzoylamino]-3-methylpentanoic acid (prepared by the general method of Example 5) in 200 mL of dichloromethane was treated dropwise with 2.4 g (15.0 mmol) of liquid bromine. The reaction mixture was stirred at room temperature for 2 hours, and the solvent was evaporated in vacuo. The residue was triturated with dichloromethane, which was also evaporated in vacuo to remove excess bromine. The residue was partitioned between dichloromethane/5% sodium bicarbonate (200 mL each). The aqueous layer was separated, washed with dichloromethane, and acidified to pH 1.5 with 6.0M hydrochloric acid. After extracting with dichloromethane (2×75 mL), the combined organic layers were washed with water, dried (MgSO4), filtered and evaporated in vacuo to give 4.8 g of the title compound, mp 50°-52° C.