1961 年 81 巻 4 号 p. 615-618
Differential thermal analysis was carried out on sulfanilamide, sulfathiazole, bromovalerylurea, and bromodiethylacetylurea, and thermal abnormality was found in all these compounds by transition of crystal form. It was also found that bromodiethylacetylurea has a γ-form, besides α- and β-forms, which is labile at a high temperature. The γ-form is stable at above ca. 90° and this was also confirmed by powder X-ray method at the time of heating.