Triethyloxonium tetrafluoroborate has been used as a selective o-alkalyting agent of lactam for preparation of the lactim ether of oxindole. The synthesis of new pyrimido 1,6 -a indole derivatives is described. Addition of dicyanomethylidene indole (1) to varicous fluorophenyl isothiocyanates gave 2- fluorophenyl -3- imino -1- thioxo -1,2,3,5-tetrahydropyrimido, 1,6-a) indole -4- carbonitrile (2). Reduction of these compounds with sodium borohydride gave the corresponding enaminonitriles 3- amino -2- fluorophenyl1-thioxo -1,2,4a , 50 tetrahydropyrimido 1,6-a indole -4 carbonitrile (3) . Treatment of enaminonitriles with chloracetyl chloride afforded the N- chloroacetylamino derivatives (4) which underwent cyclization either by acid or base to the tetracyclic compounds 3- chloromethyl (or alkylaminomethyl) -1- oxo-6- thioxo-12-12a - dihydro-[ 2H,5H ]- pyrimido  [4, 5, 4, 5] pyrimido[ 1, 6-a) indoles (5). Preliminary pharmacological screening of some compounds revealed analgesic and anti-inflammatory activities.