C[O-].[Na+].[Cl:4][CH:5](Cl)[C:6]1[S:7][CH2:8][CH:9]([C:11]([O:13][CH2:14]C)=[O:12])[N:10]=1.C(Cl)Cl.O>CO>[Cl:4][CH2:5][C:6]1[S:7][CH:8]=[C:9]([C:11]([O:13][CH3:14])=[O:12])[N:10]=1Sodium methoxide (25% w/w in MeOH (44.62 g, 206.5 mmol)) was added slowly, (over 55 min.) whilst maintaining the temperature between 0 and 10° C., to ethyl 2-(dichloromethyl)-4,5-dihydro-1,3-thiazole-4-carboxylate (50.0 g, 206.5 mmol) in 50 mL of MeOH. An additional 50 mL of MeOH was added and stirred for 1 h. keeping the temperature below 10° C. DCM (125 mL) and water (71 mL) was added to the mixture and the organic layer was separated. The aqueous layer was extracted with a further 71 mL of DCM. The combined organic layers was dried over MgSO4 and evaporated in vacuo to give the crude product (34.6 g, 87%).
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