Ethyl trifluoroacetate → 1-Tetralone

HRID 966442Notes

Reaction equation

HRID 966442 reaction equation
N1[C:9]2[C:8]3[CH:10]=[CH:11][CH:12]=[CH:13][C:7]=3[CH2:6][CH2:5][C:4]=2C=N1.FC(F)(F)C(OCC)=[O:17].C[O-].[Na+]>CO>[C:9]1(=[O:17])[C:8]2[C:7](=[CH:13][CH:12]=[CH:11][CH:10]=2)[CH2:6][CH2:5][CH2:4]1

Participants

5

Reactant 3

HCID 9794Ethyl trifluoroacetateHCID 3398588HCID 3398588, compoundHCID 10942334Sodium Methoxide

Product 1

HCID 107241-Tetralone

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

Synthetic Scheme III shows the procedure for preparation of 4,5-dihydrobenz[g]indazole compounds embraced by Formula I. In step 1, ethyl trifluoroacetate is reacted with base, such as 25% sodium methoxide in a protic solvent, such as methanol, and a 1-tetralone derivative (9) to give the intermediate diketone (10). In step 2, the diketone (10) in an anhydrous protic solvent, such as absolute ethanol or acetic acid, is treated with the free base or hydrochloride salt of a substituted hydrazine at reflux for 24 hours to afford a mixture of pyrazoles (11) and (12). Recrystallization gives the 4,5-dihydro benz[g]indazolyl-benzenesulfonamide (11).

Sources & evidence

ORD record
ord-8576afd13e6048c9adebcff1157bd42f
Source dataset
uspto-grants-2005_10
Patent number
US06951949B2

Reaction notes

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