Hydroxylamine → HCID 86761613, compound

Participants

Reaction Steps

To a solution of 1′-methyl-2′-oxo-1′,2,2′,3-tetrahydrospiro[furo[2,3-g][1,4]benzodioxine-8,3′-indole]-4′-carbonitrile (0.35 g, 1.05 mmol) in dimethylsulfoxide (10 mL) was added hydroxylamine (50% w/w solution in water, 3.0 mL). The reaction mixture was stirred for 16 h at ambient temperature, poured into water (50 mL) and extracted with ethyl acetate (3×100 mL). The combined organic extracts were washed with brine (2×50 mL), dried over magnesium sulfate, filtered and concentrated in vacuo. The residue was triturated in hexanes to afford N′-hydroxy-1′-methyl-2′-oxo-3,7-dihydro-2H-spiro[benzofuro[5,6-b][1,4]dioxine-8,3′-indoline]-4′-carboximidamide (0.37 g) as a colorless solid. To a 10 mL microwave reaction vessel were added N′-hydroxy-1′-methyl-2′-oxo-3,7-dihydro-2H-spiro[benzofuro[5,6-b][1,4]dioxine-8,3′-indoline]-4′-carboximidamide (0.20 g, 0.54 mmol), acetic anhydride (0.50 mL) and pyridine (2.00 mL). The solution was heated at 160° C. for 0.5 h in a microwave reactor, allowed to cool to ambient temperature and concentrated in vacuo. The residue was purified by column chromatography and eluted with hexanes/ethyl acetate (3/1) followed by recrystallization from diethyl ether to afford 1-methyl-4′-(5-methyl-1,2,4-oxadiazol-3-yl)-2,3-dihydrospiro[furo[2,3-g][1,4]benzodioxine-8,3′-indol]-2′(1′H)-one (0.08 g, 37%) as a colorless solid: mp 199-201° C. (diethyl ether); 1H NMR (300 MHz, CDCl3) δ 7.70 (dd, J=8.0, 0.8 Hz, 1H), 7.46 (t, J=7.9 Hz, 1H), 7.03 (dd, J=7.8, 0.8 Hz, 1H), 6.39 (s, 1H), 6.03 (s, 1H), 5.14 (d, J=8.6 Hz, 1H), 4.82 (d, J=8.6 Hz, 1H), 4.16-4.00 (m, 4H), 3.28 (s, 3H), 2.50 (s, 3H); MS (ES+) m/z 391.9 (M+1).

Provenance & Evidence