[CH3:1][C:2]1[CH:7]=[CH:6][N:5]=[C:4]([NH:8][C:9](=[O:15])[O:10][C:11]([CH3:14])([CH3:13])[CH3:12])[CH:3]=1.C([Li])CCC.[C:21](OCC)(=[O:28])[C:22]1[CH:27]=[CH:26][N:25]=[CH:24][CH:23]=1>C1COCC1>[O:28]=[C:21]([C:22]1[CH:27]=[CH:26][N:25]=[CH:24][CH:23]=1)[CH2:1][C:2]1[CH:7]=[CH:6][N:5]=[C:4]([NH:8][C:9](=[O:15])[O:10][C:11]([CH3:12])([CH3:14])[CH3:13])[CH:3]=1Tert-butyl 4-methyl-2-pyridinylcarbamate (Ihle, N. C.; Krause, A. E.; J. Org. Chem., 1996, 61(14):4810-4811; 10 g, 48.0 mmol) was dissolved in 100 mL THF and cooled to −78° C. under argon and was treated with n-butyllithium (2.5-M in hexanes, 48.0 mL, 120 mmol) such that the internal temperature did not exceed −50° C. The reaction was warmed to 20° C. for 20 min. then was recooled to −78° C. and ethyl isonicotinate (10.79 mL, 72.0 mmol) was added neat and the reaction again was warmed to 20° C. and stirred 45 minutes. The reaction was quenched with sat. NaHCO3 and extracted with ethyl acetate. The organics were dried over Na2SO4, filtered and concentrated under reduced pressure to give a red-orange oil which was purified by silica gel chromatography, eluting from 50% ethyl acetate in hexanes to 100% ethyl acetate to afford 7.56 g (50%) of the titled compound as a yellow oil.
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