Benzyl Bromide → ethyl 4-benzyl-3,4-dihydro-2H-1,4-benzoxazine-2-carboxylate

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Reaction Steps

1A was treated with sodium bicarbonate to prepare the free base (1B). A mixture of 5.3 g of 1B and 8.23 g of thallium ethoxide in 50 ml of dimethylformide was stirred at room temperature for 16 hours. 5.64 g of benzyl bromide then was added and the resulting mixture was stirred at room temperature for 5 hours. Thallium bromide precipitated and was filtered. The filtrate was stripped of solvent under reduced pressure and the residue was dry column chromatographed through silica gel using a 4:16:80 by volume mixture of tetrahydrofuran, ethyl acetate and hexane as eluent. The product was recrystallized from ether/hexane to give 1, as a solid, m.p.: 83.5°-84.5°.

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