The Ullmann reaction of an equimolar mixture of 3-iodobenzanthrone and 6-chlorobenzanthrone gave a new unsymmetrical compound, 3, 6'-dibenzanthronyl (8) (mp 344346°C) in 33% yield. 3, 8'-Dibenzanthronyl (9) (mp 338340°C) was obtained from 3-iodo and 8-chlorobenzanthrone in 50% yield by the same procedure. Isoviolanthrone B (4) and new violanthrone-analogue (10) (violanthrone C) were obtained in quantitative yield by alkali condensation of (8) and (9), respectively. Hydrocarbon (12) (violanthrene C) was obtained by the reduction of (10) with zinc dust in the mixed flux of zinc chloride and sodium chloride in 66% yield, and also isoviolanthrene (11) from (4) by the same procedure in 77% yield. The structure of (8), (9), (11) and (12) were confirmed by IR, mass spectra and elemental analysis.
Reactions of melamine (M) and benzoguanamine (BG) with ethyl chlorocarbonate (ECC) in dioxane were studied. BG reacted with ECC to give N-carboethoxybenzoguanamine as the main product and N, N-bis (carboethoxy) benzoguanamine in a poor yield. N, N-bis (carboethoxy) melamine and N-carboethoxymelamine were obtained from M and ECC. In the case of m-phenylenediamine, N, N'-bis (car-boethoxyl) derivative yielded. These results suggest rather strong electron-withdrawing effect of s-triazine ring as compared with a benzene ring.
Reactions of N, N'-disubstituted thioureas with 1-chlorobenzotriazole (1-CBT) or trichloro-isocyanuric acid (TCIA) have been investigated. Aliphatic or alicyclic N, N'-disubstituted thioureas were, allowed to react with an equimolar amount of 1-CBT or TCIA in the presence of cxcess pyridine at room temperature, giving 56-75% of the corresponding carbodiimides. At the same time, ca 70% of free sulfur was obtained. Similar reactions with excess 1-CBT or TCIA in the presence of sodium hydroxide solution were carried out to give 71-88% of carbodiimides. Alkaline solution from 1-CBT was acidified with acetic acid, after separation of carbodiimide, to obtain 1, 2, 3-benzotriazole. Alkaline solution from TCIA was acidified with conc. hydrochloric acid to give cyanuric acid.