in tetrahydrofuran mixt. refluxed for 5h, then hydrolysis of the excess Grignard reagent with satd. aq. NH4Cl; sepn. of the organic layer, drying over MgSO4, filtration, evapn., dissolution in petroleum ether, sepn. on a column containing Kieselgel, twice recrystn. (petroleum ether); elem. anal.;