Azocine derivatives. Part II. Synthesis of benzazocine derivatives by ring-expansion of dihydrobenzazepines with dibromocarbene

Abstract

Methods of ring-expansion for preparation of benzazocine derivatives have been explored. 2,3,4,5-Tetrahydro-1-p-tolylsulphonyl-1-benzazepin-5(1H)-one has been converted sequentially into the enol ether, which in turn gave a dibromocarbene adduct. This was ring-expanded to 2,3,4,5-tetrahydro-1-p-tolylsulphonyl-1-benzazocin-6(5H)-one and to the corresponding enol ether.