Thionyl Chloride → HCID 15813206, compound

Participants

Reaction Conditions

Reaction Steps

Dimethyl 6-methyl-4-methylamino-2-(4-trifluommethyl-phenyl)cyclohexa-3,5-diene-1,3-dicarboxylate (3) ##STR8## 10.0 g (25 mmol) of dimethyl 6-hydroxy-6-methyl-4-methylamino-2-(4-trifluoromethylphenyl)-cyclohex-3-ene-1,3-dicarboxylate (preparation analogous to Example II) are heated to 60° C. in 100 ml of pyridine and treated with 2.5 ml of thionyl chloride. The mixture is stirred at 60° C. for 10 minutes and concentrated, and the residue is taken up in methylene chloride, washed three times with water, dried and concentrated. The residue is grossly purified on 200 g of silica gel (petroleum ether/AcOEt=3:1) and then separated by MPLC (methylene chloride/AcOEt=30:1). Two fractions are obtained. 224 mg (2.3%) of dimethyl 4-methyl-6-methylamino-2-(4-trifluoromethylphenyl)-cyclohexa-3,6-diene-1,3-dicarboxylate (non-polar isomer (2)) crystallize from ether/petroleum ether. From the 2nd fraction, 2.29 g (22%) of the polar isomer, dimethyl 6-methyl-4-methylamino-2-(4-trifluoromethylphenyl)-cyclohexa-3,5-diene-1,3-dicarboxylate (3) are precipitated from AcOEt as the hydrochloride (Rf =0.47 (c)).

Provenance & Evidence