18-Crown-6 → Indium Ac2O AcOH

Participants

Reaction Conditions

Reaction Steps

A mixture of spray-dried KF (539 mg, 9.29 mmol), intermediate 10 (250 mg, 0.929 mmol) and catalytic amount of 18-crown-6 in dry DMSO (8 mL) was stirred at 170-180° C. for 40 min. Work-up of the reaction mixture as described in example 1 gave the residue. This residue was dissolved in a mixture of AcOH and Ac2O (1:1, 10 mL) and was added indium powder (1.06 g, 9.29 mmol) at rt. The reaction mixture was stirred at 60° C. for 30 min. The reaction mixture was attained to rt and diluted with EtOAc (50 mL). The solution was stirred for 5 min and filtered through celite. The celite bed was washed with EtOAc (2×10 mL) and the combined organic layer was evaporated under reduced pressure. The residue was chromatographed over silica gel column using chloroform:methanol (90:10) as eluents to give the product as a pale brown color solid (83 mg, 35%), mp 238-242° C. 1H NMR (400 MHz, DMSO-d6): δ 11.00 (1H, br s, exchangeable with D2O), 8.72 (1H, br s, exchangeable with D2O), 8.21 (1H, d, J=8.4 Hz), 7.34 (1H, dd, J=15.4, 8.2 Hz), 6.90 (1H, t, J=8.8 Hz), 3.63 (2H, d, J=6.0 Hz), 2.17 (3H, s); 13C NMR (100 MHz, DMSO-d6): δ 172.5, 169.7, 163.0, 158.3 (d, J=242 Hz), 138.2 (d, J=7 Hz), 130.0 (d, J=9 Hz), 116.5 (d, J=22 Hz), 116.2 (d, J=2 Hz), 109.3 (d, J=21 Hz), 43.8, 24.2; LC-MS (positive ion mode): m/z 255 (M+H)+.

Provenance & Evidence