[OH:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[CH:8]1[NH:12][C@H:11]([C:13]([OH:15])=[O:14])[CH2:10][S:9]1.C(=O)([O-])[O-].[Na+].[Na+].[Br:22][CH2:23][CH2:24][C:25](Cl)=[O:26].Cl>O>[Br:22][CH2:23][CH2:24][C:25]([N:12]1[C@H:11]([C:13]([OH:15])=[O:14])[CH2:10][S:9][CH:8]1[C:3]1[CH:4]=[CH:5][CH:6]=[CH:7][C:2]=1[OH:1])=[O:26]To a stirred solution of 22.5 g of (4R)-2-(2-hydroxyphenyl)-4-thiazolidinecarboxylic acid and 21.2 g of sodium carbonate in 200 ml of water, cooled by an ice-water bath, 18.8 g of 3-bromopropanoyl chloride is added dropwise. The resulting mixture is continuously stirred for 2 hr at room temperature, acidified with 2 N aqueous hydrochloric acid solution, and extracted with 300 ml of ethyl acetate. The organic layer is washed with brine and dried over sodium sulfate. After removal of ethyl acetate in vacuo, 100 ml of chloroform is added to the residue and the separated crystals are filtered to give 24.3 g (70%) of the product. The product is recrystallized from methanol to yield the titled compound: mp 109°-115° C.; IR (nujol) 3330, 1709, 1629, 1594, 1229, 1198, 1029 cm-1.
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