Guanidine Hydrochloride → 5-(4-Ethyl-7-methyl-benzo[b]thiophen-5-yloxy)-pyrimidine-2,4-diamine

Participants

Reaction Steps

2-(4-Ethyl-7-methyl-benzo[b]thiophen-5-yloxy)-3-phenylamino-acrylonitrile (360 mg, 1 mmol), guanidine HCl (411 mg, 4 mmol) and sodium methoxide (880 ul, 4 mmol, 4.9 M solution in methanol) in 5 mL absolute ethanol were heated to reflux in 5 ml absolute ethanol for 2 hours. Premixed guanidine HCl (411 mg, 4 mmol) and sodium methoxide (880 ul, 4 mmol, 4.9 M solution in methanol) in 1 ml EtOH was added via pipette, and the reaction mixture was heated to reflux for 2 hours. The reaction mixture was cooled, diluted with water, extracted twice with EtOAc, washed with brine, and dried over magnesium sulfate. Solvent was removed in vacuo to give 241 mg of 5-(4-Ethyl-7-methyl-benzo[b]thiophen-5-yloxy)-pyrimidine-2,4-diamine as a white solid (74%). Mass Spec M+H=301, M.P.=181° C. Recrystallization of 175 mg of this product from MeOH and HO/diethyl ether afforded 98 mg of the corresponding HCl salt 49%, Mass Spec M+H=301, M.P.>300 C.

Provenance & Evidence