Trifluoroacetic acid → (2'-Ethyl-5'-phenyl-1H,2'H-[3,3']bipyrazolyl-5-ylmethyl)-carbamic Acid Methyl Ester

To a room temperature solution of the above-prepared (2′-ethyl-5′-phenyl-1H,2′H-[3,3′]bipyrazolyl-5-ylmethyl)-carbamic acid tert-butyl ester (25 mg, 68 μmoles) in CH2Cl2 (2 mL) was added trifluoroacetic acid (0.5 mL, excess). The resulting solution was stirred at room temperature for one hour, then concentrated and azeotroped with acetonitrile (3×) in vacuo. To the resulting crude deprotection product in acetonitrile was added triethylamine, then 1-methoxycarbonyl imidazole (26 mg, 204 μmoles) and the mixture was heated to 90° C. for two hours. The reaction was then cooled to room temperature, diluted with ethyl acetate and 1 M NaHSO4, and stirred vigorously for 20 minutes. The organic phase was washed with brine, dried over Na2SO4, filtered, and concentrated in vacuo. Flash chromatography (silica gel, hexanes/ethyl acetate gradient) provided the title compound as a white solid. 1H NMR (CDCl3, 400 MHz): 7.87 (d, 2H); 7.41 (dd, 2H); 7.37 (dd, 1H); 6.75 (s, 1H); 6.42 (s, 1H); 5.30 (dd, 1H); 4.68 (q, 2H); 4.40 (d, 2H); 3.73 (s, 3H); 1.51 (t, 3H).

1. concentrationconcentrated
2. customazeotroped with acetonitrile (3×) in vacuo
3. additionTo the resulting crude deprotection product in acetonitrile was added triethylamine
4. temperatureThe reaction was then cooled to room temperature
5. stirringstirred vigorously for 20 minutes
6. washThe organic phase was washed with brine
7. dry with materialdried over Na2SO4
8. filtrationfiltered
9. concentrationconcentrated in vacuo

ORD-Eintrag

ord-cd8e24d887cf4550bdf30903b3c67454

Quelldatensatz

uspto-grants-2003_08

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US06608087B1