Carbamic acid, (5-amino-1H-pyrazol-3-yl)-, 1,1-dimethylethyl ester (9CI) synthesis

Yield:123363-50-8 100%

Reaction Conditions:

with hydrogen;palladium 10% on activated carbon in methanol;

Steps:

1.2

(5-Nitro-2H-pyrazol-3-yl)-carbamic acid tert-butyl ester (10.4 g, 45.61 mmol) was placed in a hydrogenation vessel and dissolved in methanol (150 ml). The solution was purged with nitrogen gas and 10% palladium on carbon (1.02 g, 0.958 mmol) was added to the reaction vessel while maintaining an inert environment. The vessel was placed on the Parr hydrogenator overnight. The reaction mixture was filtered over celite and concentrated under vacuo to afford 9.0 g of (5-amino-2H-pyrazol-3-yl)-carbamic acid tert-butyl ester as a foam (quantitative yield). ¹H NMR (d₆-DMSO) δ 10.9 (1H, s), 9.25 (1H, broad s), 5.57 (1H, s), 5.10 (2H, s) 1.64 (9H, s); HPLC/MS m/z: 199 [MH]⁺.

References:

US2007/173488,2007,A1 Location in patent:Page/Page column 21