Sulfuric acid magnesium salt (1:1) → 3-(5-Chloro-2-thienyl)-5,6-dihydro-1,4,2-oxathiazine-4,4-dioxide

関与物質

反応条件

反応手順

3-(5-Chloro-2-thienyl)-5,6-dihydro-1,4,2-oxathiazine (12g, 0.055 mol) prepared in Example 1, in methylene chlorine (50 ml) and anhydrous magnesium sulphate (10 g) in suspension, was stirred while m-chloroperoxybenzoic acid (34g, 50-60% material) in methylene chloride (250 ml), was added dropwise, to prepare a reaction mixture. The reaction mixture was allowed to warm to 30° C. and after the dropwise addition was externally heated to 35° C. for 10 hours by which time a negative starch/Kl test was obtained. Unwanted m-chlorobenzoic acid was then removed from the reaction mixture by extraction with aqueous sodium bicarbonate. The remaining reaction mixture was washed with water, dried (MgSO4) and evaporated to dryness. The resultant residue was chromatographed on 500 g silica gel eluting with methylene chloride, to produce 3-(5-chloro-2-thienyl)-5,6-dihydro-1,4,2-oxathiazine-4,4-dioxide (mp 113-114° C., 14.3g, Found: C 33.27, H 2.33, N 5.55; C7H6ClNO3S2 requires C 33.40, H 2.39, N 5.57).

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