A facile synthesis of 1-ethyl-3-methyl-11-phenyl-1,4-dihydro-5H-pyrazolo[3,4-c][1,5]benzodiazocin-5-ones. A new ring system

The new ring system pyrazolo[3,4-c][1,5]benzodiazocine was obtained through cyclization of the key intermediate of type 6a-d and 9, in refluxing toluene in presence of a catalytic amount of p-toluensulfonic acid, from moderate to high yields