2-[2-[4-[2-[2-(4-benzo[b][1,4]benzothiazepin-6-ylpiperazin-1-yl)ethoxy]ethyl]piperazin-1-yl]ethoxy]ethanol; Quetiapine Dipiperazine Diether Impurity; 2-[2-[4-[2-[2-[4-(dibenzo[b,f][1,4]thiazepin11-yl)piperazin-1-yl]ethoxy]ethyl]piperazin-1-yl]ethoxy]ethanol