Nitro-pyrimidines
United States Patent 3923804
Compounds of the formula ##SPC1## Wherein R1 is selected from the group consisting of H and NO2, R2, R3 and R4 are selected from the group consisting of H and ##SPC2## Are prepared by reacting picryl bromide with the appropriate pyrimidine of the formula ##SPC3## Wherein R5, R6 and R7 are selected from the group consisting of H and halogen. These compounds are used as heat resistant explosives.
US Patent References:
Explosive comprising polynitro heterocyclic and nitroaromatic compounds
DeMaris - July 1964 - 3140212
ANTIBACTERIAL 5-NITROFURYL-PYRIMIDINES
Berger et al. - November 1971 - 3621022
Explosive comprising polynitro heterocyclic and nitroaromatic compounds
DeMaris - July 1964 - 3140212
ANTIBACTERIAL 5-NITROFURYL-PYRIMIDINES
Berger et al. - November 1971 - 3621022
Inventors:
Sitzmann, Michael E. (Chevy Chase, MD)
Dacons, Joseph C. (Washington, DC)
Dacons, Joseph C. (Washington, DC)
Application Number:
05/298088
Publication Date:
12/02/1975
Filing Date:
10/04/1972
View Patent Images:
Export Citation:
Assignee:
The United States of America as represented by the Secretary of the Navy (Washington, DC)
Primary Class:
Other Classes:
544/322, 149/105
International Classes:
C06B25/04; C07D239/26; C07D239/30; C06B25/00; C07D239/00; C07D239/50
Field of Search:
149/105 260/251R
Primary Examiner:
Sebastian, Leland A.
Attorney, Agent or Firm:
Sciascia, Cooke R. S. J. A.
Claims:
What is claimed as new and desired to be secured by Letters Patent of the United States is
1. Pyrimidines of the formula ##SPC10##
2. The compound of claim 1 wherein at least 2 of R2, R3 and R4 are ##SPC12##
3. The compound of claim 1 wherein R1 is H and each of R2, R3 and R4 are ##SPC13##
4. The compound of claim 1 wherein R1 is NO2, R3 is H and each of R2 and R4 are ##SPC14##
5. The compound of claim 1 wherein R1 is NO2, R4 is H and each of R2 and R3 are ##SPC15##
1. Pyrimidines of the formula ##SPC10##
2. The compound of claim 1 wherein at least 2 of R2, R3 and R4 are ##SPC12##
3. The compound of claim 1 wherein R1 is H and each of R2, R3 and R4 are ##SPC13##
4. The compound of claim 1 wherein R1 is NO2, R3 is H and each of R2 and R4 are ##SPC14##
5. The compound of claim 1 wherein R1 is NO2, R4 is H and each of R2 and R3 are ##SPC15##
Description:
BACKGROUND OF THE INVENTION
This invention generally relates to explosives and more particularly to explosives with excellent heat stability.
Use of explosives in many different types of devices is widely known in the prior art. However, despite the huge number of explosives that are known there are relatively few that can withstand high temperatures of at least 280°C or above without substantial deterioration. Since explosives in many specialized uses are subjected to temperatures of about 280°C or higher there has been a constant search for explosive materials which will not deteriorate substantially due to high temperatures.
SUMMARY OF THE INVENTION
Accordingly, one object of this invention is to provide new chemical compounds.
Another object of this invention is to provide chemical compounds that can be used as explosives.
A further object of this invention is to provide explosive compounds which are capable of withstanding temperatures of at least about 280°C without substantial deterioration.
A still further object of this invention is to provide explosive compounds which can be used in environments wherein high temperatures are a problem (i.e., where aerodynamic heating is a problem).
Yet another object of this invention is to provide explosive compounds which can be used in mild detonating cord and flexible linear shaped charges.
These and other objects of this invention are accomplished by providing chemical compounds of the formula ##SPC4##
Wherein R 1 is selected from the group consisting of H and NO 2 and R 2 , R 3 and R 4 are selected from the group consisting of H and ##SPC5##
Which are prepared by reacting picryl bromide or any picryl halide, with the appropriate pyrimidine of the formula ##SPC6##
Wherein R 5 , R 6 and R 7 are selected from the group consisting of H and a halogen.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Compounds of the formula ##SPC7##
Wherein R 1 is H or NO 2 and R 2 , R 3 and R 4 are H or ##SPC8##
Are prepared by contacting a picryl halide, such as picryl bromide, with a pyrimidine of the formula ##SPC9##
Wherein R 5 , R 6 and R 7 are H or halogen. This reaction is the typical, well known Ullman biaryl synthesis. The pyrimidine is dissolved in a solvent such as nitrobenzene and copper is added. The picryl halide is then added dropwise to the above solution over a period of about 1/2 hour and the temperature is maintained around 150°C throughout. Following this the solutions are purified using typical purification techniques.
The general nature of the invention having been set forth, the following examples are presented as specific illustrations thereof. It will be understood that the invention is not limited to these specific examples but is susceptible to various modifications that will be recognized by one of ordinary skill in the art.
EXAMPLE 1
PICRYL BROMIDE
An amount of 355 g (3.5 moles) of reagent grade potassium nitrate was dissolved in 800 ml of 30% oleum in a 2000 ml 3-neck round bottom flask fitted with a mechanical stirrer and a thermometer. During the addition of the potassium nitrate, the mixture was cooled and stirred on an ice bath, the temperature being kept below 60°C. When the addition was complete, the mixture was cooled to 30°C and 79 g (0.5 moles) of bromobenzene was added at such a rate as to keep the temperature below 50°C. The ice bath was then replaced by an oil bath and the reaction mixture was heated to approximately 125°C for four hours. After cooling, the mixture was drowned in crushed ice, the product was collected by filtration using a sintered glass funnel and thoroughly washed with water. After drying in a warm oven, it was dissolved in 100 ml of acetone, 300 ml of methanol was added and the solution was cooled in the freeze compartment of the refrigerator. On filtration, 83.7 g of pale yellow crystalline picryl bromide, mp 120°-122°C (lit. 122°-3°C) was recovered. The filtrate was concentrated to about 150 ml by boiling on the steam bath and again cooled in the freeze compartment. The second crop weighed 28.0 g and melted over the range 111°-118°C. On recrystallization from acetone-ethanol, an additional 21.0 g of crystalline product, mp 120°-122°C was obtained to give a total yield melting at this temperature of 104.7 g, 71.6%. Samples melting at 122°-123°C were obtained by one additional recrystallization from acetone-methanol.
EXAMPLE 2
2, 4, 6 - TRIPICRYLPYRIMIDINE 3-neck
A vigorously stirred mixture of 22.0 g (1.12 moles) of 2,4,6-trichloropyrimidine (commercially available) and 106.7 g (1.68 moles) of copper in 120 ml of nitrobenzene was heated to 145°C in a 1000 ml 3-neck round bottom flask equipped with a mechanical stirrer, a thermometer and an addition funnel. A solution of 140.2 g (0.48 moles) of picryl bromide in 210 ml of nitrobenzene was added over a period of 25 minutes. During the addition and for five minutes thereafter, a temperature range of 1 /2°-150°C was maintained. The reaction mixture was then cooled to 70°C and stirred into 1300 ml of methanol. After cooling to 10°C, the mixture was filtered, the solid residue was washed with methanol and digrested in 1200 ml of 20% aqueous HCl at 50°-60°C to remove the copper salts. After filtering and washing with dilute HCl, water and finally methanol, the dark brown residue on the funnel was dissolved in 280 ml of dimethylsulfoxide at 100°C. The solution was treated with 35 g of activated charcoal. The solution was then filtered and the charcoal pad was washed with 75 ml of hot dimethylsulfoxide. A volume of 1500 ml of methanol was slowly added to the filtrate to precipitate the product. On cooling to 10°C, filtering and washing with methanol, 52.6 g of a tan product which partially melted at ca 230°C, resolidified and melted finally at 335°-340° C was collected. This product, which was a solvate, was dissolved in 175 ml of nitrobenzene at 175° C. The solution was allowed to cool to room temperature, filtered, and the cream colored crystalline product was thoroughly washed with methanol. After drying in a warm oven, the product weighed 43.3 g, partially melted at 230°C and melted finally at 341°-2° C (dec). An additional crop of 8.1 g obtained from the filtrate showed similar melting characteristics except that its final melting point was 337°-9° C. Both crops were combined and recrystallized from 155 ml of nitrobenzene. The yield was 45.6 g of yellow crystals which melted the same as the first crop above. After drying under vacuum at 145°-150° C for 4.5 hours, 38.9 g (45.4%) of a cream colored crystalline product, m.p. 341°-2° C (dec) was recovered.
EXAMPLE 3
2,4-DIPICRYL-5-NITROPYRIMIDINE
A vigorously stirred mixture of 5.28 g (0.03 moles) of 2,4-dichloro-5-nitropyrimidine (prepared by the procedure of N. W. Whittaker, J. Chem. Soc., 1565-70 (1951)) and 17.6 g (0.28 moles) of copper in 20 ml of nitrobenzene was rapidly heated to 145° C in a 100 ml 3-neck around bottom flask equipped with a mechanical stirrer, a thermometer and an addition funnel. A solution containing 23.4 g (0.08 moles) of picryl bromide in 40 ml of nitrobenzene was added dropwise over a period of 25 minutes. The temperature range of 145°-150° C was maintained during the addition and for five minutes thereafter. The dark brown mixture was then cooled to 70° C and stirred into 500 ml of methanol. The mixture was cooled to 10° C, filtered and the solid residue was digested in 400 ml of 20% HCl HC at 60-70° C for 10 minutes to remove the copper salts. The residue was recovered by filtration, and after washing with dilute HCl, water and finally methanol, it was dissolved in 50 ml of dimethylsulfoxide by heating to 80° C. The dark brown solution was treated with activated charcoal, filtered and the charcoal pad was washed with a small amount of hot dimethylsulfoxide. The product was precipitated by adding 300 ml of methanol and cooling in an ice bath. On filtration, 9.25 g of light brown crystals, m. p. 325°-6° C (dec) were recovered. This product was recrystallized by dissolving in 60 ml of nitrobenzene at 180° C, and cooling to room temperature. The yellow crystalline product was recovered by filtration and washed with methanol. On drying, it weighed 8.0 g and melted with decomposition at 327°-8° C. An additional 0.95 g (same melting point) was obtained by adding 150 ml of methanol to the mother liquor. The total yield was 8.95 g (54.6%).
EXAMPLE
4,6-DIPICRYL-5-NITROPYRIMIDINE
A vigorously stirred mixture of 23.3 g (0.12 moles) of 4,6-dichloro-5-nitropyrimidine (commercially available) and 71.1 g (1.12 moles) of copper in 100 ml of nitrobenzene was rapidly heated to 145° C in a 500 ml 3-neck round bottom flask fitted with a mechanical stirrer, a thermometer and an addition funnel. A solution of 93.5 g (0.32 moles) of picryl bromide in 140 ml of nitrobenzene was added over a period of 25 minutes. A temperature range of 145°-150°C was maintained during the addition and for five minutes thereafter. The dark brown mixture was cooled to 70° C and poured into 1000 ml of methanol. After cooling to 10° C, the solid residue was removed by filtration and washed with methanol. The residue was extracted by stirring in 1500 ml of boiling acetone and the mixture was filtered while hot. The filtrate was treated with 20 g of activated charcoal and filtered. The filtrate was then concentrated by rapid distillation with stirring until considerable crystallization had occurred and the volume was about 250 ml. Methanol was then added at about the same rate as the distillate was removed until the temperature of the distillate was 62° C. Approximately 500 ml of methanol was required. The mixture was then cooled to room temperature, filtered, and the cream colored crystalline product was washed with methanol. On drying, the product weighed 31.0 g (47.3%) and melted at 349°-350° C with decomposition. An additional crystallization did not improve the melting point of the product and reduced the yield only slightly to 30.6 g (46.7%).
Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described herein.
This invention generally relates to explosives and more particularly to explosives with excellent heat stability.
Use of explosives in many different types of devices is widely known in the prior art. However, despite the huge number of explosives that are known there are relatively few that can withstand high temperatures of at least 280°C or above without substantial deterioration. Since explosives in many specialized uses are subjected to temperatures of about 280°C or higher there has been a constant search for explosive materials which will not deteriorate substantially due to high temperatures.
SUMMARY OF THE INVENTION
Accordingly, one object of this invention is to provide new chemical compounds.
Another object of this invention is to provide chemical compounds that can be used as explosives.
A further object of this invention is to provide explosive compounds which are capable of withstanding temperatures of at least about 280°C without substantial deterioration.
A still further object of this invention is to provide explosive compounds which can be used in environments wherein high temperatures are a problem (i.e., where aerodynamic heating is a problem).
Yet another object of this invention is to provide explosive compounds which can be used in mild detonating cord and flexible linear shaped charges.
These and other objects of this invention are accomplished by providing chemical compounds of the formula ##SPC4##
Wherein R 1 is selected from the group consisting of H and NO 2 and R 2 , R 3 and R 4 are selected from the group consisting of H and ##SPC5##
Which are prepared by reacting picryl bromide or any picryl halide, with the appropriate pyrimidine of the formula ##SPC6##
Wherein R 5 , R 6 and R 7 are selected from the group consisting of H and a halogen.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Compounds of the formula ##SPC7##
Wherein R 1 is H or NO 2 and R 2 , R 3 and R 4 are H or ##SPC8##
Are prepared by contacting a picryl halide, such as picryl bromide, with a pyrimidine of the formula ##SPC9##
Wherein R 5 , R 6 and R 7 are H or halogen. This reaction is the typical, well known Ullman biaryl synthesis. The pyrimidine is dissolved in a solvent such as nitrobenzene and copper is added. The picryl halide is then added dropwise to the above solution over a period of about 1/2 hour and the temperature is maintained around 150°C throughout. Following this the solutions are purified using typical purification techniques.
The general nature of the invention having been set forth, the following examples are presented as specific illustrations thereof. It will be understood that the invention is not limited to these specific examples but is susceptible to various modifications that will be recognized by one of ordinary skill in the art.
EXAMPLE 1
PICRYL BROMIDE
An amount of 355 g (3.5 moles) of reagent grade potassium nitrate was dissolved in 800 ml of 30% oleum in a 2000 ml 3-neck round bottom flask fitted with a mechanical stirrer and a thermometer. During the addition of the potassium nitrate, the mixture was cooled and stirred on an ice bath, the temperature being kept below 60°C. When the addition was complete, the mixture was cooled to 30°C and 79 g (0.5 moles) of bromobenzene was added at such a rate as to keep the temperature below 50°C. The ice bath was then replaced by an oil bath and the reaction mixture was heated to approximately 125°C for four hours. After cooling, the mixture was drowned in crushed ice, the product was collected by filtration using a sintered glass funnel and thoroughly washed with water. After drying in a warm oven, it was dissolved in 100 ml of acetone, 300 ml of methanol was added and the solution was cooled in the freeze compartment of the refrigerator. On filtration, 83.7 g of pale yellow crystalline picryl bromide, mp 120°-122°C (lit. 122°-3°C) was recovered. The filtrate was concentrated to about 150 ml by boiling on the steam bath and again cooled in the freeze compartment. The second crop weighed 28.0 g and melted over the range 111°-118°C. On recrystallization from acetone-ethanol, an additional 21.0 g of crystalline product, mp 120°-122°C was obtained to give a total yield melting at this temperature of 104.7 g, 71.6%. Samples melting at 122°-123°C were obtained by one additional recrystallization from acetone-methanol.
EXAMPLE 2
2, 4, 6 - TRIPICRYLPYRIMIDINE 3-neck
A vigorously stirred mixture of 22.0 g (1.12 moles) of 2,4,6-trichloropyrimidine (commercially available) and 106.7 g (1.68 moles) of copper in 120 ml of nitrobenzene was heated to 145°C in a 1000 ml 3-neck round bottom flask equipped with a mechanical stirrer, a thermometer and an addition funnel. A solution of 140.2 g (0.48 moles) of picryl bromide in 210 ml of nitrobenzene was added over a period of 25 minutes. During the addition and for five minutes thereafter, a temperature range of 1 /2°-150°C was maintained. The reaction mixture was then cooled to 70°C and stirred into 1300 ml of methanol. After cooling to 10°C, the mixture was filtered, the solid residue was washed with methanol and digrested in 1200 ml of 20% aqueous HCl at 50°-60°C to remove the copper salts. After filtering and washing with dilute HCl, water and finally methanol, the dark brown residue on the funnel was dissolved in 280 ml of dimethylsulfoxide at 100°C. The solution was treated with 35 g of activated charcoal. The solution was then filtered and the charcoal pad was washed with 75 ml of hot dimethylsulfoxide. A volume of 1500 ml of methanol was slowly added to the filtrate to precipitate the product. On cooling to 10°C, filtering and washing with methanol, 52.6 g of a tan product which partially melted at ca 230°C, resolidified and melted finally at 335°-340° C was collected. This product, which was a solvate, was dissolved in 175 ml of nitrobenzene at 175° C. The solution was allowed to cool to room temperature, filtered, and the cream colored crystalline product was thoroughly washed with methanol. After drying in a warm oven, the product weighed 43.3 g, partially melted at 230°C and melted finally at 341°-2° C (dec). An additional crop of 8.1 g obtained from the filtrate showed similar melting characteristics except that its final melting point was 337°-9° C. Both crops were combined and recrystallized from 155 ml of nitrobenzene. The yield was 45.6 g of yellow crystals which melted the same as the first crop above. After drying under vacuum at 145°-150° C for 4.5 hours, 38.9 g (45.4%) of a cream colored crystalline product, m.p. 341°-2° C (dec) was recovered.
EXAMPLE 3
2,4-DIPICRYL-5-NITROPYRIMIDINE
A vigorously stirred mixture of 5.28 g (0.03 moles) of 2,4-dichloro-5-nitropyrimidine (prepared by the procedure of N. W. Whittaker, J. Chem. Soc., 1565-70 (1951)) and 17.6 g (0.28 moles) of copper in 20 ml of nitrobenzene was rapidly heated to 145° C in a 100 ml 3-neck around bottom flask equipped with a mechanical stirrer, a thermometer and an addition funnel. A solution containing 23.4 g (0.08 moles) of picryl bromide in 40 ml of nitrobenzene was added dropwise over a period of 25 minutes. The temperature range of 145°-150° C was maintained during the addition and for five minutes thereafter. The dark brown mixture was then cooled to 70° C and stirred into 500 ml of methanol. The mixture was cooled to 10° C, filtered and the solid residue was digested in 400 ml of 20% HCl HC at 60-70° C for 10 minutes to remove the copper salts. The residue was recovered by filtration, and after washing with dilute HCl, water and finally methanol, it was dissolved in 50 ml of dimethylsulfoxide by heating to 80° C. The dark brown solution was treated with activated charcoal, filtered and the charcoal pad was washed with a small amount of hot dimethylsulfoxide. The product was precipitated by adding 300 ml of methanol and cooling in an ice bath. On filtration, 9.25 g of light brown crystals, m. p. 325°-6° C (dec) were recovered. This product was recrystallized by dissolving in 60 ml of nitrobenzene at 180° C, and cooling to room temperature. The yellow crystalline product was recovered by filtration and washed with methanol. On drying, it weighed 8.0 g and melted with decomposition at 327°-8° C. An additional 0.95 g (same melting point) was obtained by adding 150 ml of methanol to the mother liquor. The total yield was 8.95 g (54.6%).
EXAMPLE
4,6-DIPICRYL-5-NITROPYRIMIDINE
A vigorously stirred mixture of 23.3 g (0.12 moles) of 4,6-dichloro-5-nitropyrimidine (commercially available) and 71.1 g (1.12 moles) of copper in 100 ml of nitrobenzene was rapidly heated to 145° C in a 500 ml 3-neck round bottom flask fitted with a mechanical stirrer, a thermometer and an addition funnel. A solution of 93.5 g (0.32 moles) of picryl bromide in 140 ml of nitrobenzene was added over a period of 25 minutes. A temperature range of 145°-150°C was maintained during the addition and for five minutes thereafter. The dark brown mixture was cooled to 70° C and poured into 1000 ml of methanol. After cooling to 10° C, the solid residue was removed by filtration and washed with methanol. The residue was extracted by stirring in 1500 ml of boiling acetone and the mixture was filtered while hot. The filtrate was treated with 20 g of activated charcoal and filtered. The filtrate was then concentrated by rapid distillation with stirring until considerable crystallization had occurred and the volume was about 250 ml. Methanol was then added at about the same rate as the distillate was removed until the temperature of the distillate was 62° C. Approximately 500 ml of methanol was required. The mixture was then cooled to room temperature, filtered, and the cream colored crystalline product was washed with methanol. On drying, the product weighed 31.0 g (47.3%) and melted at 349°-350° C with decomposition. An additional crystallization did not improve the melting point of the product and reduced the yield only slightly to 30.6 g (46.7%).
Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described herein.