SU650504A3 - Method of obtaining methyl-(2-quinoxalinylmethylene)-carbazate-n',n4-dioxide - Google Patents

Description

By diluting the mother liquor with water, 7.7-8.1 g (25-30%) of beisofuroxan can be isolated, which can be used again in the reaction.

Example 3. Production of 2-formyl-oxy-1, 4-dioxydimethyl acetal.

15 ml of ammonium hydroxide (25% aqueous solution) are added but dropwise to a solution of 26 g (0.22 mol} meliglyoxalidimethyleetal and 27.2 g (0.21) of benzofuroxane in 45 ml of dimethylformamide at a temperature below 30 ° C , the reaction mixture is stirred or allowed to stand at room temperature for 20 hours. The separated crystals are filtered off with cold methanol to give 32.8 g (69.5%) of a yellow crystalline 2-form 11 Lxpnoxalin-1, 4 - dioxide dimethyl acetal, m.p. 148-149 ° C. An additional amount of 20.8 g (0.18 mol) of methyl glyoxalmethyl acetal and 21.7 g, (0.16 m ol) benzofuroxan is injected into the mother liquor, the reaction mixture is left to stand for one day. The separated and the product is filtered and washed with methanol, to obtain 35.4 g (75%) of a celizable compound, mp 150 ° C.

The use of the appropriate; its equipment kazaipa reaction can be carried out continuously with a high number of repetitions.

PRI me R 4. Obtaining methyl- (2-hypoxyalylmethyl) -carbazate-, - dioxide.

26.6 g (0.1 mol) of 2-formylquinokalin1, 4-dioxide dimethyl acetal and 10 g (0.11 mol) of methyl carbazate are suspended in 200 ml of WATER. 8 ml of concentrated hydrochloric acid is added to the suspension, and the mixture is stirred on a water bath heated to 95-100 ° C for 20 minutes. During this period, the reactants are released and the product begins to separate. The mixture was stirred at room temperature for 1 hour, then cooled and the product was filtered off. The product is washed with water, ethanol and chloroform. Get

26.6 g (97.8%) of yellow cryetallic methyl- (2-quinoxalinylmethyl) -carbazate CHL-diokeide. The product decomposes at 260 C.

Example 5. Obtaining methyl- (2-hioksaliplmetilen) -carbazate - M, N-dioxide.

5.7 g (0.11 mol) of 98% gpdrazingidr; 1 t is added dropwise to a suspension of 9.9 g (0.11 mol) of dimethyl carbonate in 25 ml of methanol, the reaction mixture is not stirred at room temperature for 2 h Thereafter, methanol and unreacted hydrazium, which is possibly present, are removed by distillation, the residue is diluted with 20 ml of water and a solution of 23.6 g (0.1 mol} of 2-formyl xy) 10xalin-1,4 - dioxidimethyl ista L in 200 ml of warm water containing 2 ml of concentrated hydrochloric acid. The resulting suspension is cooled to a compote temperature tours and do not react at this temperature for 45 minutes. The supernatant was filtered off and washed with water, ethanol and chloroform-yum. 24.5 g (93.5%) of crystalline yellow methyl- (2-quinoxalsenylmetlipl) carbazate-M were obtained, S - Dioxide. The product decomposes Irie 258-260 C.

Claims (1)

1. Patent of Germany No. 1927337, cl. 12 p, 6. 968.