Ethyl Bromide → tert-butyl 4-{1-[(1-ethyl-1H-tetrazol-5-yl)methyl]-2,4-dioxo-6-phenyl-1,4-dihydrothieno[3,2-d]pyrimidin-3(2H)-yl}piperidine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a solution of the tautomeric mixture of tert-butyl 4-[2,4-dioxo-6-phenyl-1-(2H-tetrazol-5-ylmethyl)-1,4-dihydrothieno[3,2-d]pyrimidin-3(2H)-yl]piperidine-1-carboxylate and tert-butyl 4-[2,4-dioxo-6-phenyl-1-(1H-tetrazol-5-ylmethyl)-1,4-dihydrothieno[3,2-d]pyrimidin-3(2H)-yl]piperidine-1-carboxylate (255 mg; compound B14b) in DMF (5 ml) under nitrogen atmosphere is added lithium hydride (5.0 mg). After 10 min at RT bromoethane (163 mg) is added. The mixture is stirred for 1.5 h at 40° C. then all volatile materials are removed in vacuo. The residue is purified by flash column chromatography [silica gel, eluation gradient: hexanes/EtOAc/triethylamine, 16/3/1 to 5/4/1 (v/v/v)] to give the two separated isomers tert-butyl 4-{1-[(1-ethyl-1H-tetrazol-5-yl)methyl]-2,4-dioxo-6-phenyl-1,4-dihydrothieno[3,2-d]pyrimidin-3(2H)-yl}piperidine-1-carboxylate (compound B15) and tert-butyl 4-{1-[(2-ethyl-2H-tetrazol-5-yl)methyl]-2,4-dioxo-6-phenyl-1,4-dihydrothieno[3,2-d]pyrimidin-3(2H)-yl}piperidine-1-carboxylate (compound B14) as solids.

Provenance & Evidence