Triethylamine → Thymine

Participants

Reaction Steps

5.5 g, of N-(thymin-1-ylacetyl)-piperazinone (20.6 mmol) was suspended in 200 mL of dry DCM and treated with 3.77 g (1.5 eq, 30.9 mmol) DMAP, 11.23 g (51.5 mmol, 2.5 eq) Boc-anhydride and 7.2 mL (51.5 mmol, 2.5 eq) of triethylamine. The reaction also results in protection of the secondary amino group on the thymine. The reaction mixture was stirred at room temperature for 3-4 hours, while following the reaction progress by TLC. Upon completion, the reaction mixture was concentrated by rotary evaporation, and the resulting oil was resuspended in DCM. The organic phase was washed successively with 0.1 N HCl solution (2×25 mL), water (2×100 mL) and dried over sodium sulfate. Concentration and purification by recrystallization from diethyl ether afforded 6 g of the Boc-protected thymine PNA precursor (80% yield) as a white solid.

Provenance & Evidence