Sodium triacetoxyborohydride → 6-[(4S)-4-{[3-(7-Methoxy-2-oxoquinoxalin-1(2H)-yl)propyl]amino}-2-oxopyrrolidin-1-yl]-2H-pyrido[3,2-b][1,4]oxazin-3(4H)-one

Participants

Reaction Steps

6-[(4S)-4-Amino-2-oxopyrrolidin-1-yl]-2H-pyrido[3,2-b][1,4]oxazin-3(4H)-one (94.1 mg, 0.379 mol) and 3-(7-methoxy-2-oxoquinoxalin-1(2H)-yl)propanal (Reference Example 8; 106 mg, 0.456 mmol) were dissolved in chloroform/methanol (10:1, v/v, 6 ml). Molecular sieve 3 A (powder, 1.0 g) was added to the solution and heated under reflux for 3 hours. After cooling, sodium triacetoxyborohydride (145 mg, 0.684 mmol) was added to the reaction mixture and the mixture was stirred overnight at room temperature. After completion of the reaction, the molecular sieve was removed by filtration and a saturated sodium hydrogen carbonate aqueous solution was added to the filtrate and stirred. After separating the organic layer, the aqueous layer was extracted twice with chloroform/methanol (10:1, v/v) and combined with the organic layer. The organic layer was dried over anhydrous magnesium sulfate and the solvent was removed under reduced pressure. The obtained residue was purified by thin-layer chromatography (chloroform/methanol) to yield 56 mg (32%) of the title compound in the form of a colorless solid.

Provenance & Evidence