Diisopropylethylamine → tert-butyl 3-amino-6,6-dimethyl-1-{[2-(trimethylsilyl)ethoxy]methyl}-4,6-dihydropyrrolo[3,4-c]pyrazole-5(1H)-carboxylate

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Reaction Conditions

Reaction Steps

To a suspension of tert-butyl 3-amino-6,6-dimethyl-4,6-dihydropyrrolo[3,4-c]pyrazole-5(1H)-carboxylate (8.5 g, 33.9 mmol) and diisopropyl ethylamine (18 mL, 3.0 equiv) in dichloromethane (200 mL) was added 2-(trimethylsilyl)ethoxymethyl chloride (6.0 mL, 1.0 equiv) dropwise at 0° C. under nitrogen. The mixture was been stirred at 0° C. under nitrogen for two hours then warmed to room temperature and stirred over night. The reaction mixture was concentrated and purified by column chromatography to give the title compound J(i) as a white solid (2.27 g, 18%). 1H NMR (400 MHz, METHANOL-d4): δ ppm 0.81-0.97 (m, 2H) 1.45-1.59 (m, 9H) 1.72 (d, J=5.29 Hz, 13H) 3.53-3.67 (m, 2H) 4.26 (d, J=7.55 Hz, 2H) 5.17 (s, 2H). 2D-NOESY NMR showed proton at 5.17 ppm is correlated with proton at 1.72 ppm.

Provenance & Evidence