Quantitative after sodium-hydroxide treatment

On standing, diphenyldiazomethane decomposes to yield benzophenone azine. In one of the checkers runs the product was stored at room temperature after 2 days, crystals of the azine were visible. The product at this stage was assayed by treatment with benzoic acid addition of 6.8 g. of the diazo compound in a thin stream to a solution of 17 g. of benzoic acid in 90 ml. of ether, and, after 30 minutes, extraction of the excess benzoic acid with dilute sodium hydroxide followed by distillation of the ether, gave 7.4 g. (75%) of crude benzohydryl benzoate melting at 83-85°. In the same procedure the freshly prepared diazo compound gave a quantitative yield of the crude ester. 

In 1909, 4-amino-6-methyl-l,3,5-triazin-2-ol was obtained by cyclization of (acetylcarbamimi-doyl)urca under basic conditions.443 Subsequently, several new processes based on acylated dicyanodiamides were developed.444-447,449 Thus, when acyldicyanodiamides 1 are heated to reflux in 2-ethoxyethanol, 4-amino-1,3,5-triazin-2-ols 2 are obtained in crude yields of 60 to 100%.444,445 Catalytic amounts of amine salts significantly accelerate this reaction. After selective acid hydrolysis of acyldicyanodiamides, (acylcarbamimidoyl)ureas 3 are obtained which can also be cyclized to the 1,3,5-triazines 2. These reactions are carried out in excess sodium hydroxide solution and provide the triazines in 90 to 99% yield.443,444,446 447 Cyclization of 1-acylbiurets 4, prepared by acid hydrolysis of (acylcarbamimidoyl)ureas 3, is effected by treatment with potassium hydroxide solution.444,448 While the benzoyl derivative 3 (R = Ph) yields the corresponding l,3,5-triazine-2,4-diol 5 (R = Ph) in quantitative yield, the acetyl derivative 3 (R = Me) cyclizes only partially to the corresponding triazinediol 5 (R = Me).448... 

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