Ethyl chloroacetate → Ethyl 3-amino-4,5,6,7-tetrahydrobenzo[2,1-d]selenophene-2-carboxylate

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To a suspension of sodium selenide (4.7 g, 37.3 mmol, prepared from 3.0 g of selenium as described above) in DMF (37 mL) was added a solution of 2-chlorocyclohex-1-enecarbonitrile (5.24 g, 37.3 mmol) in DMF (18 mL) at rt for 5 min and stirred the mixture at 60° C. for 45 min. The reaction mixture was allowed to rt and added ethyl chloroacetate (3.16 mL, 37.3 mmol) dropwise for 5 min. The reaction mixture was stirred at 60° C. for 3 h. Then, a solution of sodium methoxide (2.0 g, 37.3 mmol) in methanol (37 mL) was added dropwise and stifling was continued for 2 h at the same temperature. The mixture was allowed to rt and poured into ice cold water and stirred for 15 min. The solution was extracted with chloroform (3×200 mL) and the combined chloroform layer was washed with water, brine and dried over sodium sulfate. The solution was filtered and evaporated the solvent. The residue was chromatographed over silica gel column using hexane-EtOAc (90:10) as eluents to give the product as a yellow color oil of a mixture of ethyl and methyl ester (2.4 g, 25%). 1H NMR (400 MHz, CDCl3): δ 5.54 (2H, s, —NH2), 4.24 (2H, q, J=7.1 Hz, —COOCH2CH3), 2.74-2.75 (2H, m, H-7), 2.27-2.28 (2H, m, H-4), 1.81-1.84 (4H, m, H-5,6), 1.31 (3H, t, J=7.1 Hz, —COOCH2CH3); LC-MS (positive ion mode): m/z 294, 296 (M+Na)+.

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