Diisopropylethylamine → (+/-)-4-[(3,3-Dimethyl-cyclobutyl)-(3-methyl-quinolin-2-ylamino)-methyl]-benzoic acid ethyl ester

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Reaction Steps

(+/−)-4-[amino-(3,3-dimethyl-cyclobutyl)-methyl]-benzoic acid ethyl ester (Intermediate 24) (45 mg, 0.17 mmol) was combined with 3-methylquinoline-N-oxide (27.4 mg, 0.172 mmol, Alfa Aesar, Ward Hill, Mass., USA) and dichloromethane (2 mL). Diisopropylethylamine (0.112 mL, 0.645 mmol) was added followed by bromotripyrrolidinophosphonium hexafluorophosphate (109 mg, 0.224 mmol). The solution was stirred at room temperature for 28 h before partitioning between ethyl acetate and aq. sat. NaHCO3. The separated aqueous layer was extracted with additional ethyl acetate and the combined organics dried over MgSO4. Purification by silica gel flash chromatography (ethyl acetate/heptane) gave (+/−)-4-[(3,3-dimethyl-cyclobutyl)-(3-methyl-quinolin-2-ylamino)-methyl]-benzoic acid ethyl ester (44.0 mg) as a clear oil. 1H NMR (400 MHz, CDCl3) δ 7.96 (d, J=8.4 Hz, 2 H) 7.56-7.62 (m, 2 H) 7.46-7.53 (m, 3 H) 7.38-7.46 (m, 1 H) 7.12-7.20 (m, 1 H) 5.33 (dd, J=9.5, 6.7 Hz, 1 H) 4.77 (d, J=6.6 Hz, 1 H) 4.34 (q, J=7.2 Hz, 2 H) 2.67 (sxt, J=8.8 Hz, 1 H) 2.30 (s, 3 H) 1.97 (ddd, J=11.1, 8.1, 3.2 Hz, 1 H) 1.74-1.85 (m, 1 H) 1.66-1.73 (m, 2 H) 1.36 (t, J=7.1 Hz, 3 H) 1.16 (s, 3 H) 1.10 (s, 3 H); MS (M+1): 403.3.

Provenance & Evidence