In the pres. ent synthesis we proceeded from 2.{2-naphthylthio) benzoic acid4 (VII) which was obtained by. a reaction of 2-thionaphthoI5, 6 with 2-iodobenzoic acid7 in boiling aqueous solution of potassium hydroxide in the presence of copper. The other steps were analogous to the synthesis of benzo [b] naphtho [2, 1-J] thiepin