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 dichloromethene (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 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