Sodium triacetoxyborohydride → 1-{2-[(3R,4S)-4-({[5-chloro-6-(hydroxymethyl)-3-pyridinyl]methyl}amino)-3-hydroxy-1-piperidinyl]ethyl}-7-(methyloxy)-1,5-naphthyridin-2(1H)-one

Participants

Reaction Steps

A mixture of 1-{2-[(3R,4S)-4-amino-3-hydroxy-1-piperidinyl]ethyl}-7-(methyloxy)-1,5-naphthyridin-2(1H)-one (Intermediate 33 as a free base: 200 mg, 0.628 mmol) and 5-chloro-6-(hydroxymethyl)-3-pyridinecarbaldehyde (108 mg, 0.628 mmol) in DCE (10 ml) and Methanol (0.5 ml) was stirred at room temperature overnight. Sodium triacetoxyborohydride (399 mg, 1.885 mmol) was added. The mixture was stirred under N2 at rt for 6 h. LCMS showed imine and desired compound. An excess of sodium triacetoxyborohydride (399 mg, 1.885 mmol) was added. The mixture was stirred overnight. Full conversion to the amine was observed by LCMS. It was quenched with saturated NaHCO3, extracted with DCM/MeOH 9/1, dried (MgSO4), filtered, and concentrated affording 242 mg of crude material. Purification by manual flash chromatography using a 5 g Merck silica gel cartridge, and DCM/MeOH 9/1 as eluent afforded 1-{2-[(3R,4S)-4-({[5-chloro-6-(hydroxymethyl)-3-pyridinyl]methyl}amino)-3-hydroxy-1-piperidinyl]ethyl}-7-(methyloxy)-1,5-naphthyridin-2(1H)-one (179.8 mg, 0.360 mmol, 57% yield) as a white solid.

Provenance & Evidence