KH in N,N-dimethyl acetamide (vac. or Ar); treatment of soln. of urea deriv. in dimethylacetamide with KH, addn. of nickel compd., stirring for 45 min, addn. of potassium tert-butoxide, addn. of tetramethylammonium salt, stirring for 1 h; evapn. triturating with diethyl ether, isolation of ppt., elem. anal.;
