Isobutylene → 8,8-Dimethyl-6-(3-morpholin-4-yl-phenyl)-5,6,7,8-tetrahydro-[1,5]naphthyridine-2-carbonitrile

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Reaction Conditions

Reaction Steps

To a stirred solution of 5-{[1-(3-morpholin-4-yl-phenyl)-meth-(E)-ylidene]amino}-pyridine-2-carbonitrile (22.9 g, 78.4 mmol) in acetonitrile (150 mL) were added isobutene (21.0 mL, 313.5 mmol) and ytterbium(III) trifluoromethanesulfonate (Yb(OTf)3) (5.8 g, 9.5 mmol). The resulting mixture was stirred at 90° C. for 18 h in sealed tube. The mixture was diluted with ethyl acetate (300 mL) and washed with water (100 mL×2) and brine (100 mL×2) and then dried over anhydrous sodium sulfate. The solvent was removed in vacuo and the residue was purified by ISCO combi-flash chromatography (gradient elution, 10-50% ethyl acetate in petroleum ether) to afford 8,8-dimethyl-6-(3-morpholin-4-yl-phenyl)-5,6,7,8-tetrahydro-[1,5]naphthyridine-2-carbonitrile (3.3 g, 12.1%) as a light yellow solid: MS (ESI) M+1=349.1.

Provenance & Evidence