3,5-Dimethylpyrazole → HCID 66615637, compound

Temperature

-20 °C

At −30° C., a solution of 3,5-dimethyl-1H-pyrazole (7.2 g, 74.9 mmol) in dichloromethane (40 ml) was treated with CrO3 (7.5 g, 74.9 mmol, added in two portions) while the reaction temperature rose to −20° C. The resulting mixture was stirred at −20° C. for 0.5 h and treated within 20 min. with a solution of α-bulnesene (3.0 g, 14.7 mmol) in dichloromethane (20 ml) while the reaction temperature rose to −10° C. The resulting mixture was stirred between −20° C. and −10° C. for 4 h before allowing the reaction temperature to slowly reach 20° C. (overnight), treated with 8M aqueous NaOH (70 ml), stirred at 20° C. for 20 h, and extracted with MTBE (400 ml). The aqueous phase was extracted with MTBE (150 ml) and the joined organic phases were washed twice with 2 M aq. HCl (100 ml), once with H2O (100 ml), once with aqueous saturated NaCl solution (100 ml), dried with MgSO4, filtered, and the solvent evaporated. FC (200 g 0.015-0.040 mm-SiO2, flow: 60 ml/min., hexane/methyl t-butyl ether 100:0 to 85:15 in 30 min.) of the crude product (2.4 g) gave (3S,3aS,5R)-3,8-dimethyl-5-(prop-1-en-2-yl)-3,3a,4,5,6,7-hexahydroazulen-1(2H)-one (130 mg, 4%).

1. customrose to −20° C
2. customrose to −10° C
3. stirringThe resulting mixture was stirred between −20° C. and −10° C. for 4 h
4. customto slowly reach 20° C. (overnight)
5. stirringstirred at 20° C. for 20 h
6. extractionextracted with MTBE (400 ml)
7. extractionThe aqueous phase was extracted with MTBE (150 ml)
8. washthe joined organic phases were washed twice with 2 M aq. HCl (100 ml), once with H2O (100 ml), once with aqueous saturated NaCl solution (100 ml)
9. dry with materialdried with MgSO4
10. filtrationfiltered
11. customthe solvent evaporated

ORD record

ord-3526fafa6d9846f3977ddb83b5ea790b

Source dataset

uspto-grants-2014_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08883468B2