Diisopropylethylamine → (R)-methyl 1-(4-fluorophenyl)-6-((3-(trifluoromethyl)phenyl)sulfonyl)-4,4a,5,6,7,8-hexahydro-1H-pyrazolo[3,4-g]isoquinoline-4a-carboxylate

A solution of (R)-6-tert-butyl 4a-methyl 1-(4-fluorophenyl)-4a,5,7,8-tetrahydro-1H-pyrazolo[3,4-g]isoquinoline-4a,6(4H)-dicarboxylate (2.0 g, 4.68 mmol) in 20% trifluoroacetic acid/dichloromethane (50 mL) was stirred at room temperature for 1 hour. The solvent was removed in vacuo, azeotroping three times with toluene (˜20 mL), to give a dark orange oil. The oil was dissolved in dichloromethane (50 mL) and 3-(trifluoromethyl)benzene-1-sulfonyl chloride (0.900 ml, 5.61 mmol) was added followed by diisopropylethylamine (4.09 ml, 23.39 mmol). The reaction mixture was stirred at room temperature for 20 minutes, and then solvent removed in vacuo to give a dark orange oil. The crude product was purified by chromatography on silica gel (gradient: 0-45% ethyl acetate in isohexane) to afford (R)-methyl 1-(4-fluorophenyl)-6-((3-(trifluoromethyl)phenyl)sulfonyl)-4,4a,5,6,7,8-hexahydro-1H-pyrazolo[3,4-g]isoquinoline-4a-carboxylate (931 mg) as a pale yellow solid. LCMS (Method F, ES-API): RT 2.62 min, m+H=536.2.

1. customThe solvent was removed in vacuo
2. customazeotroping three times with toluene (˜20 mL)
3. customto give a dark orange oil
4. customsolvent removed in vacuo
5. customto give a dark orange oil
6. customThe crude product was purified by chromatography on silica gel (gradient: 0-45% ethyl acetate in isohexane)

ORD record

ord-865bb578d23a4b5c9f0dcef43f332708

Source dataset

uspto-grants-2014_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08859774B2