[OH:1][C@@H:2]1[C@H:6]2[N:7]([C:21]([O:23][C:24]([CH3:27])([CH3:26])[CH3:25])=[O:22])[CH2:8][C@@H:9](OS(C3C=CC(C)=CC=3)(=O)=O)[C@H:5]2[O:4][CH2:3]1.[CH3:28][S-:29].[Na+].[Cl-].[NH4+]>CC(N(C)C)=O>[OH:1][C@@H:2]1[C@H:6]2[N:7]([C:21]([O:23][C:24]([CH3:25])([CH3:26])[CH3:27])=[O:22])[CH2:8][C@H:9]([S:29][CH3:28])[C@H:5]2[O:4][CH2:3]1A stirred solution of tosylate (35b) (250 mg, 0.63 mmol) and sodium thiomethoxide [CAS 5188-07-8] (88 mg, 1.25 mmol) in 3 ml of DMA was heated under an atmosphere of argon in a sealed pressure vessel at 90° C. for 2 hours. The mixture was then allowed to cool to ambient temperature then an aqueous saturated solution of ammonium chloride (10 mL) was added. The aqueous phase was extracted with tert-butyl methyl ether (3×7 ml). The organic phase was dried (MgSO4), filtered and reduced in vacuo to leave an oil. Flash chromatography over silica, eluting with diethyl ether:pentane 2:1 gave thiomethylether (54) as colourless oil (0.152 g, 88%). TLC(Rf=0.29, Et2O:pentane 2:1), HPLC-MS 220.1 [M+2H−tBu]+, 573.2 [2M+H]+; δH (500 MHz, CDCl3) mixture of rotamers 1:1; 1.46 (4.5H, s, CCH3), 1.49 (4.5H, s, CCH3), 2.16 (3H, s, SCH3), 3.20 (1H, brs, BocNCH2), 3.47-4.05 (4H, m, OCH2CHOH, BocNCH2 and CHSCH3), 4.24-4.45 (2H, m, BocNCH and OCH2CHOH), 4.63 (1H, s, OCHCHSCH3).
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