Mannitol 1,2,3,5,6-pentanitrate

Later, Wigner [15] found that by heating with pyridine nitromannitol is denitrated to mannitol pentanitrate, and Hayward [20] has confirmed the denitration to pentanitrate by means of pyridine, occurring even at room temperature. After some 15 hr about a 65% yield is obtained. 

Hayward produced eyidence that the pentanitrate so obtained has the structure of D-mannitol-l,2,3,5,6-pentanitrate. Methylation of the pentanitrate with silver oxide and methyl iodide gave 4-methyl-D-mannitol pentanitrate (m.p. 111—112°C). 

Nitromannitol can be obtained by nitrating mannitol with a mixture of nitric acid and sulphuric acid. The method is inconvenient, however, since the reaction produces a thick crystalline mass and the nitration proceeds unevenly [8]. Generally therefore, mannitol is dissolved in a five-fold amount of nitric acid (d — 1.51) at a temperature below 0°C, which is maintained while a ten-fold quantity of sulphuric acid (d = 1.84) is added to the solution. Fine crystals of the product are precipitated which were separated on a vacuum filter. The product is slightly impure due to the presence of mannitol pentanitrate. The acid product is drowned quickly in cold water, filtered again, washed with cold water, neutralized by means of dilute sodium bicarbonate solution and once again washed with water. Nitromannitol is crystallized from alcohol, to which a stabilizer (diphenylamine) is added. 

Interest has focused on derivatives of mannitol hexanitrate (14) as potential explosives because although this nitrate ester is a powerful explosive it has some property characteristics of a primary explosive. Treatment of mannitol hexanitrate (14) with pyridine or ammonium carbonate " in aqueous acetone leads to a very selective denitration with the formation of mannitol-1,2,3,5,6-pentanitrate (77). Marans and co-workers synthesized the acetate (78), the propionate (79), and the phenylacetate (80) derivatives of mannitol-1,2,3,5,6-pentanitrate and all have significantly lower melting points than mannitol hexanitrate. The incorporation of such groups can also help to increase the solubility of an explosive in the melt of another explosive. 

Mannitol hexanitrate is obtained by nitration of mannitol with mixed nitric and sulfuric acids. Similarly, nitration of sorbitol using mixed acid produces the hexanitrate when the reaction is conducted at 0—3°C and at —10 to —75°C, the main product is sorbitol pentanitrate (117). Xylitol, ribitol, and L-arabinitol are converted to the pentanitrates by fuming nitric acid and acetic anhydride (118). Phosphate esters of sugar alcohols are obtained by the action of phosphorus oxychloride (119) and by alcoholysis of organic phosphates (120). The 1,6-dibenzene sulfonate of D-mannitol is obtained by the action of benzene sulfonyl chloride in pyridine at 0°C (121). To obtain 1,6-dimethanesulfonyl-D-mannitol free from anhydrides and other by-products, after similar sulfonation with methane sulfonyl chloride and pyridine the remaining hydroxyl groups are acetylated with acetic anhydride and the insoluble acetyl derivative is separated, followed by deacetylation with hydrogen chloride in methanol (122). Alkyl sulfate esters of polyhydric alcohols result from the action of sulfur trioxide—trialkyl phosphates as in the reaction of sorbitol at 34—40°C with sulfur trioxide—triethyl phosphate to form sorbitol hexa(ethylsulfate) (123). 

D-Glucitol hexanitrate256 and the pentanitrates of xylitol,257 ribitol,257 and L-arabinitol257 have been partially denitrated by the action of pyridine, but the structures of the reaction products were not ascertained. The dinitrates of the 1,4.3,6-dianhydro derivatives of D-mannitol, D-glucitol, and L-iditol react only slowly in anhydrous pyridine,258 and only traces of mononitrates could be detected in aqueous pyridine, mononitrates accounted for a maximum of 10% of the decomposed dinitrates. 

D-Marmitolbexanitrate. This compd in pyridine evolved gases (NO, N20 N) and mannitol - 1,2 4,5,6 - pentanitrate and CgH5N.HN03, after dilution with water. Approx 2 moles of CgHgN suffered ring cleavage, 0.25 mole of the hexani-trate was completely denitrated, and 0.75 mole of pentanitrate was formed (Ref 3)... 

D-Mannitol hexanitrate and galactitol hexanitrate are, however, converted readily and exothermically by pyridine, or by ammonium carbonate in aqueous acetone, into 1,2,3,5,6-pentanitrates. In the denitration by pyridine, nitric and nitrous oxides and nitrogen are evolved. Moisture is required in the pyridine in order to provide the proton which replaces the nitronium ion (NOj ). The use of rigorously dried pyridine greatly reduced the yield, but, as the water content was increased, the yield rose to a maximum of 75 %. 

Sorbitol is dissolved to five times volume of concentrated nitric acid (d = 1.52 at 0 °C). The product can be precipitated by 10 times volume of 20 % finned sulfuric acid (5 °C). In the product, there is a small amount of impurity of pentanitrate. At 0-10 °C of nitration and precipitation temperamre, an oily mixture of sorbitol hexanitrate and sorbitol pentanitrate will be obtained. The explosion property of nitro sorbitol is similar with that of nitro mannitol. 

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