tert-Butyl methyl ether → 10H-pyrazolo[1',5':1,2]imidazo[4,5-c]quinolin-6-amine

Participants

Reaction Steps

A solution of 10-[(4-methylphenyl)sulfonyl]-10H-pyrazolo[1′,5′:1,2]imidazo[4,5-c]quinolin-6-amine (0.13 g, 0.34 mmol) and sodium ethoxide (0.032 g, 0.38 mmol) in ethanol (3.5 mL) was heated to 85° C. After 1.5 h, the reaction was cooled to ambient temperature, quenched with silica gel (1.3 g) and concentrated under reduce pressure. The material was loaded onto a 40 g silica gel cartridge and purified by prep. HPLC (eluted with 10-30% CMA in chloroform) to give a red/orange solid. The solid was treated with methyl tert-butyl ether (10 mL) and heated to boiling. The hot mixture was filtered through fine filter paper and the filtrate concentrated to yield 20 mg of 10H-pyrazolo[1′,5′:1,2]imidazo[4,5-c]quinolin-6-amine as a mauve solid, mp, dec>200° C.; 1H NMR (500 MHz, DMSO-d6) δ 11.58 (s, 1H), 8.53 (dd, J=7.9, 1.1 Hz, 1H), 7.93 (d, J=2.1 Hz, 1H), 7.68 (d, J=8.1 Hz, 1H), 7.53-7.50 (m, 1H), 7.41-7.38 (m, 1H), 6.73 (s, 2H), 6.04 (d, J=2.1 Hz, 1H); 13C NMR (125 MHz, DMSO-d6) δ 147.5, 145.9, 143.5, 143.3, 127.2, 125.8, 123.9, 122.4, 121.2, 117.7, 113.4, 80.4; MS (ESI) m/z 224.22 (M+H)+.

Provenance & Evidence