8,8,10,10-Tetrachloro-3-phenoxy-1,2,4,5,7,9,11-heptaaza-3,6.lambda.~5~,8.lambda.~5~,10.lambda.~5~-tetraphosphaspiro[5.5]undeca-6,8,10-triene 3-oxide AIDS-137693 AIDS137693 NSC642782