Ammonia → 5'-Methylspiro[chromane-4,2'-imidazole]-4',6-diamine

Participants

Reaction Steps

A mixture of 6-bromo-5′-methylspiro[chroman-4,2′-imidazol]-4′-amine (Intermediate 4, 115 mg, 0.39 mmol), trans-4-hydroxy-L-proline (51 mg, 0.39 mmol), CuI (37 mg, 0.20 mmol), and K2CO3 (162 mg, 1.17 mmol) in DMSO (0.9 mL) was stirred at r.t. for 15 min. Ammonia, (30-33% in H2O, 0.37 mL, 5.86 mmol) was added and the mixture was subjected to microwave irradiation at 110° C. for 3 h. The mixture was diluted with DMSO and water and filtered through a pad of diatomaceous earth. NaCl (s) was added and the aqueous mixture was extracted with EtOAc (5×35 mL). The combined organic phases were dried (Na2SO4) and evaporated to give a crude product which was purified by flash chromatography (4 g silica, eluent: CHCl3/(MeOH/NH3) gradient) affording the title compound (59 mg, 65% yield). 1H NMR (400 MHz, DMSO-d6) δ ppm 1.76-1.92 (m, 2 H), 2.19 (s, 3 H), 4.18-4.34 (m, 2 H), 4.45 (br. s., 2H), 5.69 (d, 1 H), 6.35 (dd, 1 H), 6.45 (br. s., 2 H), 6.50 (d, 1 H); MS (ES−) m/z 231 [M+H]+.

Provenance & Evidence