Methyl iodide → 2-Methoxyethyl 4-hydroxy-2-methyl-2H-1,2-benzothiazine-3-carboxylate 1,1-dioxide

Beteiligte Stoffe

Reaktionsschritte

2-Methoxyethyl 4-hydroxy-2H-1,2-benzothiazine-3-carboxylate 1,1-dioxide (31.0 g., 0.1035 mole) was combined with 230 ml. of acetone and cooled to 10° C. Methyl iodide (21.9 g., 0.155 mole) was added, followed by the dropwise addition, over 10 minutes, of sodium hydroxide (103.5 ml. of 1 N). The cooling bath was removed and the reaction mixture allowed to slowly warm to room temperature (about 45 minutes), then heated at 35° C. for 2 hours and finally at 39°-40° C. for 16 hours. The reaction mixture was cooled to room temperature, diluted with 200 ml. of acetone, treated with activated carbon, filtered and concentrated in vacuo at 0°-5° C. to about 50 ml. The resulting slurry was filtered, and solids washed with ice-water and then dried in vacuo to yield 2-methoxyethyl 4-hydroxy-2-methyl-2H-1,2-benzothiazine-3-carboxylate 1,1-dioxide [29.26 g., 90%; m.p. 106°-107.5° C.; m/e 313; ir(KBr) 3345, 2941, 1684, 1351, 1053 cm-1 ].

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