DE1198372B - Process for the preparation of tris- (1, 3, 2-diazaborolo) -borazines - Google Patents

Description

Process for the preparation of tris- (1, 3,2-diazaborolo) -borazines It is known from U.S. Patent No. 2,948,751. that by implementing Boric acid trialkyl esters with optionally substituted o-phenylenediamines Tris - (3 H -1,3,2 - benzo - diazaborolo) borazine is obtained. The one made from o-phenylenediamine however, the product obtained did not have a sharp melting point. rather it decomposes the borazine already 30 to 60 ° C below the melting point, which is likely to occur Impurities is due. The cited patent continues shows that long reaction times are required. z. B. at a temperature from 150 ° C 18 hours. Nevertheless, the yield of alcohol was an indication of the yield of raw product. not quantitative.

It has now been found that tris- (1,3.2-diazaborolo) -borazines of the general formula in which A is part of a fused benzene ring optionally substituted by methyl, carboxy or carbalkoxy groups or a fused naphthalene or pyridine ring, if an o-phenylenediamine, an o-naphthylenediamine or o- Pyridylenediamine in the presence or absence of a high-boiling solvent at an initial temperature of at least 80 ° C and an end temperature of about 160 to 2500 C and a pressure below 50 Torr with a boric acid triaryl ester.

The starting materials used are, for. B. o-phenylenediamine, 2.3- or 3 * STolylenediamine. o-xylylenediamine. Diaminobenzoic acid and its derivatives. like 3.4-diaminobenzoic acid methyl ester, 2,3- or 3,4-I) iaminopyridine, 1,2- or 2,3-naphthylenediamine.

If one reacts phenylenediamine with boric acid triphenyl ester. the reaction proceeds according to the following reaction equation: First 2 moles of phenol per mole of boric acid ester are split off with formation of 1,3-dihydro-2-phenoxy-1,3.2-benzodiazaborole. On further heating, a third mole of phenol distills off, forming the borazine.

The process according to the invention can be carried out in high-boiling solvents operated, such as. B. bromobenzene, but can also very well in the melt Perform without solvents.

The product obtained can be worked up by recrystallization from suitable solvents such as dioxane.

According to the process according to the invention, the tris - (3 H - 1,3,2 - benzoborolo) - borazine surprisingly in shorter reaction times and longer Purity obtained as by the method of U.S. Patent 2,948,751.

The compounds which can be prepared according to the invention are intermediates for further syntheses. They can also be used as a fuel additive and lubricants. as biocidal compounds. as stabilizers in plastic compounds and as filling material in gas chromatographic columns.

Example 1 Tris- (3 H-1.3.2-benzodiazaborolo) -borazine 108 g of o-phenylenediamine and 290 g of triphenyl borate are placed in a round bottom flask. which is provided with a short descending cooler and a template cooled with ice water. heated in an oil bath while stirring. until a clear melt results at 100 ° C. After a pressure of 10 to 15 Torr has been generated in the apparatus by means of a water jet pump, the temperature of the oil bath is increased to 1200 ° C. Under these conditions, 180 g of phenol distilled into the receiver within 30 minutes A solid body then begins to separate out of the melt, the amount of which increases steadily as the temperature of the oil bath rises further. After a test duration of 3 hours, finally at 200.degree. no more phenol distills into the template. After this time the phenol yield is 276 g, corresponding to 98% of the theoretically calculated amount. The contents of the flask (1.20 g) are crushed in a mortar and dissolved in 2 liters of hot dioxane. After cooling to 40 to 300 ° C., about 40 to 50 g of pieces of ice are added to the solution at room temperature, regardless of any crystals already present, and the solution is stirred while cold. The resulting colorless precipitate is filtered off with suction and freed from residual solvent at 150 ° C. in a high vacuum.

The yield of colorless, microcrystalline product is 86 g (81.501o of theory). The substance melts at 410 to 4110 C. The molecular weight the compound was determined to be 347 after Rast in naphthylamine as solvent.

C18H15B3N6 (molecular weight: 347.8) calculated. . C 62.2, H 4.34, B 9.32, N 24.15%; Found ... C 62.55, H 4.50, B 9.45, N 23.85%.

Example 2 Tris- (3 H-5- or -6-methyl-1, 3,2-benzodiazaborolo) -borazine 200 g of 4-methyl-o-phenylenediamine and 475 g of boric acid triphenyl ester are, as described in Example 1, heated to 1200 ° C. in an oil bath, a pale yellow melt resulting. After evacuating the apparatus to 10 Torr, the phenol formed distilled into the ice-cold receiver. After one hour, about two thirds of the theoretically expected phenol has distilled into the receiver.

Then the oil bath temperature is increased to 160 ° C, at the same time separates a gray-brown colored solid emerges from the melt. After 3 hours is still one third of the theoretical amount of phenol is distilled off and the experiment is terminated, the reaction product is crushed in a mortar and placed in 1.8 l of dioxane while boiling Reflux dissolved, filtered hot and stirred cold. After cooling to 25 "C it will about 100 g of pieces of ice are added with stirring and the colorless precipitate freed from the solvent on a suction filter. After drying in a high vacuum at 120 ° C, the yield is 138 g (67.2% of theory). The substance melts at 350 to 351 ° C and provides a clear red-brown melt.

C21H21B3N6 (molecular weight: 389.9) Calculated ... C 64.65, H 5.43, B 8.33, N 21.55%; Found ... C 65.15, H 5.97, B 7.69, N 21.69 ° / o.

Example 3 Tris (3 H-5- or -6-carbomethoxy-1,3,2-benzdiazaborolo) borazine 8.3 g of 3,4-diaminobenzoic acid methyl ester and 14.5 g of boric acid triphenyl ester are weighed into the apparatus described in Example 1, the apparatus is evacuated to 10 Torr and the flask is then placed in an oil bath heated to 100 to 1200C. Immediately a reddish melt forms, and within a few minutes 8.3 g of phenol distill into the ice-cold receiver. After increasing the temperature to 200 ° C., more phenol (5.2 g) distilled into the receiver. After a total of 2 hours of the experiment, the mixture is allowed to cool and the solid reaction product is dissolved in dioxane and precipitated again as a gel by adding ice.

After vacuuming and washing with ether it remains on the suction filter a light gray solid, which has the following characteristics when heated: 200 ° C: unchanged; 250 ° C.: browning and sintering (gas evolution); 420 "C: jet black and glassy; 465 "C: not melted yet.

When inserting the melting point tube into the pre-warmed to 235 ° C Copper block melts the substance at 240 to 242 ° C (red melt) under stormy conditions Gas development and solidifies again immediately. The yield was 5.65 g (650/0 der Theory), based on diaminobenzoic acid methyl ester.

C24H21B3N606 (molecular weight: 521.9) Calculated ... B 622%; found ... B 6.15% and 637 ° / o.

Example 4 Tris- (1 H- or 3H-pyrido [2,3-d] [1,3,2] -diazaborolo) -borazine 11.9 g of 2,3-diaminopyridine, 29 g of boric acid triphenyl ester and 20 ml of bromobenzene are weighed into a 100 ml round bottom flask, which is provided with a short descending condenser and receiver. The apparatus is then evacuated to 10 Torr using a water jet pump. The evacuated flask is then immersed in an oil bath preheated to 100.degree. whereby the diaminopyridine goes into solution with a dark brown color. After 10 minutes, a pale yellow colored crystals are formed, but without phenol having already formed.

When the temperature of the oil bath now increases, distillation initially occurs the bromobenzene.

The crystal slurry that has formed then dissolves again at 140 ° C. and At 150 to 160 ° C, phenol gets into the receiver, which is cooled with ice water. After total 5 hours. in the last hour at 180 ° C. have 28 g of phenol in the template condensed.

The reaction product is a brown resin. It is crushed in a mortar and boiled in 100 ml of dimethyl sulfoxide. After cooling, it is decanted and Boiled again with ethanol ether and decanted. After a final ether extraction the residue is dried.

The product obtained in this way. 6.6 g (56.50 / 0 of theory). is a light gray powder and is practically insoluble in organic solvents.

The substance does not change color when heated, but then melts sharp at 446 ° C with brown discoloration.

C15H12B3N9 (molecular weight: 350.8) Calculated ... C 51.28, H 3.45. N 35,900 / 0; found . . C 50.06. H 3.69. N 35.77%.

Example 5 Tris- (1 H- or 3 H-naphtho [1,2-d] [1,3,2] -diazaborolo) -borazine 100 g of 1,2-diaminonaphthalene and 185 g of boric acid triphenyl ester are melted at 120.degree. C. in analogy to the aforementioned Examples 1 to 4.

From the deep red colored melt distilled at 10 Torr and one Oil bath temperature of 150 to 160 ° C phenol in the ice-cold receiver. After 2 hours the amount of distilled phenol is 100 g. After this time it begins Solidify reaction product. Another 50 g of phenol are at 160 ° C and 1 Torr withdrawn from the reaction product. When it has cooled down, it becomes what is present in gray chunks Crude product first extracted with petroleum ether to remove traces of phenol, and then dissolved in 11 dioxane. Crystallized from the hot filtered solution Overnight rose-colored crystals which melt at 438 ° C. with a red-brown color. The yield is 37.5 g (350 / o of theory).

C30H21B3N6 (molecular weight: 498.0) Calculated ... C 72.25, H 4.25, B 6.52, N 16.860 / 0; found ... C, 73.83. H 4.34, B 6.60, N 16.950 / o.

Claims (1)

Claim: Process for the preparation of tris- (1,3,2-diazaborolo) -borazines of the general formula NH A B N N HN-B B N N A in the A part of an optionally fused-on benzene ring substituted by methyl, carboxy or carbalkoxy groups or a fused-on naphthalene or pyridine ring, characterized in that that one is optionally substituted by methyl, carboxy or carbalkoxy groups o-phenylenediamine. an o-naphthylenediamine or o-pyridylenediamine in the presence or absence a high-boiling solvent at an initial temperature of at least 80 ° C and a final temperature of about 160 to 250 ° C and a pressure below 50 Torr reacted with a boric acid triaryl ester. References considered: U.S. Patent No. 2,948 751