Sulfuric acid magnesium salt (1:1) → HCID 44512920, compound

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Reaction Steps

A mixture of (1R)-1-[(4-amino-1-piperidinyl)methyl]-1,2-dihydro-4H,9H-imidazo[1,2,3-ij]-1,8-naphthyridine-4,9-dione (Example 1 step (j): 70.5 mg, 0.235 mmol), 5-methyl-6-(trifluoromethyl)-3-pyridinecarbaldehyde (Preparation 12: 37 mg, 0.196 mmol) and magnesium sulphate (anhydrous) (58.9 mg, 0.489 mmol) in DCM (7 ml) was stirred overnight at RT. LCMS on the crude product showed imine and not starting material was present. Rt of the desired compound was 2.59 [M+H] 472.2. Then sodium triacetoxyborohydride (124 mg, 0.587 mmol) was added and the mixture was stirred for 3 hours. LCMS showed imine so 1 eq. sodium triacetoxyborohydride (41.5 mg, 0.196 mmol) was added. Saturated aqueous sodium bicarbonate solution was added to the organic phase until pH9 was achieved. The organic phase was extracted with DCM and isolated, dried over anhydrous sodium sulphate, filtered and concentrated under reduced pressure. The residue was purified by Flash-Master chromatography on a 2 g silica gel cartridge using DCM/MeOH 5% to obtain three batches (9.3 mg). 1H NMR was consistent with the desired compound, and LCMS was consistent with the desired compound [M+H]+ 474, Rt=1.81 purity 95%.

Provenance & Evidence