Modified synthesis of 11-[14C]-clozapine.

The reported synthetic pathway of 8-chloro-11-(4-methyl-1-piperazinyl)-11-[14C]-5H-dibenzo[b,e][1,4]diazapine (clozapine) was modified in several steps. The synthetic pathway was shortened by 60% and the total yield was increased from 6% to 23%.