Triethylamine → HCID 68713643, compound

Participants

Reaction Conditions

Reaction Steps

(S)-1-Phenylethyl alcohol (1.0 g) and 1,1′-carbonyldiimidazole (1.33 g) are dissolved in tetrahydrofuran (20 ml), and the mixture is stirred at 80° C. for 2 hours. To the reaction solution are added (2R*,4S*)-4-amino-2-ethyl-6-methoxy-3,4-dihydro-2H-[1,5]naphthyridine-1-carboxylic acid ethyl ester (1.91 g) and triethylamine (1.14 ml), and the mixture is heated to reflux for 3 days. The reaction solution is partitioned by adding ethyl acetate and a saturated aqueous sodium bicarbonate solution, and then the organic layer is washed with saturated brine and dried over magnesium sulfate, then concentrated under reduced pressure. The residue is purified by column chromatography (silica gel; hexane:ethyl acetate=90:10→70:30). The resulting mixture of diastereomers is recrystallized from hexane to give (2R,4S)-2-ethyl-6-methoxy-4-((S)-1-phenylethoxycarbonylamino)-3,4-dihydro-2H-[1,5]naphthyridine-1-carboxylic acid ethyl ester (345 mg). The physical property data are the same as the compound obtained in Example 2 (3).

Provenance & Evidence