1-((R)-2,2-dimethyl-[1,3]dioxolan-4-ylmethyl)-3-nitro-1H-pyrazole → (R)-1-((2,2-Dimethyl-1,3-dioxolan-4-yl)methyl)-1H-pyrazol-3-amine

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Reaction Steps

1-((R)-2,2-Dimethyl-[1,3]dioxolan-4-ylmethyl)-3-nitro-1H-pyrazole (14.5 g) in ethanol (60 mL) was treated with 10% palladium on activated carbon (1.4 g). The mixture was placed on a Parr shaker and exposed to hydrogen (50 psi) for 16 h. After this time, the mixture was filtered through diatomaceous earth. The filtrate was concentrated in vacuo to afford 1-((R)-2,2-dimethyl-[1,3]dioxolan-4-ylmethyl)-1H-pyrazol-3-ylamine (12.4 g, 98%) as an amorphous yellow oil; ESI-LRMS m/e calcd for C9H15N3O2 [M+H+] 198, found 198 [M+H+]. 1H NMR (300 MHz, DMSO-d6) δ ppm 1.24 (s, 3H), 1.30 (s, 3H), 3.70 (dd, J=8.5, 6.0 Hz, 1H), 3.85-4.02 (m, 3H), 4.28 (quin, J=6.0 Hz, 1H), 4.56 (s, 2H), 5.36 (d, J=2.1 Hz, 1H), 7.30 (d, J=2.1 Hz, 1H).

Provenance & Evidence