C([O:3][C:4]([C:6]1[S:13][C:12]2[C:11]3[S:14][C:15]4[C:19]([CH2:20][CH2:21][CH2:22][CH2:23][CH2:24][CH2:25][CH2:26][CH2:27][CH2:28][CH3:29])=[C:18]([C:30]([O:32]CC)=[O:31])[S:17][C:16]=4[C:10]=3[S:9][C:8]=2[C:7]=1[CH2:35][CH2:36][CH2:37][CH2:38][CH2:39][CH2:40][CH2:41][CH2:42][CH2:43][CH3:44])=[O:5])C.[Li+].[OH-].C1COCC1>[I-].C([N+](CCCC)(CCCC)CCCC)CCC.CO>[CH2:20]([C:19]1[C:15]2[S:14][C:11]3[C:12]4[S:13][C:6]([C:4]([OH:5])=[O:3])=[C:7]([CH2:35][CH2:36][CH2:37][CH2:38][CH2:39][CH2:40][CH2:41][CH2:42][CH2:43][CH3:44])[C:8]=4[S:9][C:10]=3[C:16]=2[S:17][C:18]=1[C:30]([OH:32])=[O:31])[CH2:21][CH2:22][CH2:23][CH2:24][CH2:25][CH2:26][CH2:27][CH2:28][CH3:29]Compound 74 (14.0 g, 0.021 mol) is mixed with LiOH (1.24 g, in 15 mL water), THF (100 mL), MeOH (20 mL) and a catalytic amount of tetrabutylammonium iodide. This mixture is heated at reflux overnight and most of the solvent is evaporated. The residue is acidified with concentrated HCl (30 mL). The resultant solid is collected by filtration, washed thoroughly with water and vacuum dried to yield compound 75 (12.5 g, 97.4% yield). M.P.: 315.6-318.5° C.
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