Studies in nitration of thiochroman

Thiochroman is a light yellow highly refractive oil, which was prepared frist in 1905 by Von Braum by reacting potasium ethyl zanthate and the diaso salt of o-([gamma]-chloropropyl-)anilin. A second method of synthesis was discovered in 1923 by krollpfeiffer and Schults, who oxidized [beta]-phenlmercaptopropionic acid with concentrated sulfuric acid to thiochromanone and reduced the thiochromanone by the Clemenson method to thiochroman. The following compounds were prepared by this method: 6-methylthiochroman; 6,8-dimethylthiochroman; 7,8-benzothiochroman; and 5,6-benzothiochroman. In 1946 Cagniant and Deluserche prepared acyl dreivatives by direct substitution. In 1950 Cagniant and Cagniant prepared 6-bromothiochroman by direct substitution, and from this compound they prepared 6-cyanthiochroman, 6-carboxythiochroman, and 6-acetylthiochroman. The purpose of this investigation was to determine which of the two methods of synthesis was most suitable for the preparation of large quantities of Thiochroman, and to clarify the orientation in the thiochroman nucleus by the study of its nitration reactions...