Thymine → 1-Ethylthymine

Participants

Reaction Steps

A stirring suspension of thymine (536 mg, 4.18 mmol) in dry DMF (5 mL) was added sodium hydride (60% oil dispersion, 167 mg, 4.18 mmol). After stirring the mixture for 30 min at room temperature, a solution of trans-5-bromomethyl-2-ethoxyphosphinoyl-tetrahydrofuran (example 66) (630 mg, 2.09 mmol) in DMF (3 mL) was added via cannula. The mixture was then stirred at 900° C. for 18 h after which the mixture was cooled and quenched with saturated ammonium chloride (5 mL). The volatiles were removed under vacuo and the residue was dissolved in a mixture of dichloromethane (20 mL) and water (10 mL). The mixture was filtered and the aqueous layer was collected and extracted with dichloromethane (2×20 mL). The combined extracts were then washed with brine (20 mL), dried (MgSO4) and concentrated to dryness. Purification by chromatography eluting with EtAc, 5% MeOH in EtAc then 10% MeOH in EtAc yielded first N1 -ethyl thymine (83 mg, 26%) and then the title compound as an oil (186 mg, 26%).

Provenance & Evidence