Nitrate esters general

Generally, the successful conversion of 20-ketopregnanes to 17-hydroxy-androstanes with peracids requires the protection of other ketones, with the exception of those at C-11, and possibly C-12 e.g., as ketals or cyanohydrins ) and isolated double bonds e.g., as dibromides). Unprotected hydroxyl groups do not interfere, except, as expected, a 17a-hydroxy-20-keto steroid is oxidized to the 17-ketone. The use of nitrate esters to protect... 

Nitrostarch (NS) is a nitrate ester (more properly a mixt of several nitrate esters) of starch, which is a plant-product polysaccharide of the general formula (CgHujOj) The general molecular formula for NS is [C6H7(OH)x-(0NO2)y]n where x + y - 3, The following empirical relation, similar to that used for NC... 

At best, expl power i a somewhat nebulous quantity. If we consider relative power as measured in a Ballistic Mortar or Trauzl Block, then OB correlates reasonably well with relative power, provided these comparisons are made for similar expls. This is illustrated in Fig 1, where Ballistic Mortar measurements axe respectively correlated with OB for nitro, nitramine, nitrate ester and aluminized expls. In general Ballistic Mortar measurements are more reproducible than Trauzl Block data. Consequently we have shown these in preference to Trauzl Block measurements. Correlation between Trauzl block data and OB are reported in Refs 1 8... 

The general mechanism of nitrating alcohols to form nitrate esters is described under Nitration in this Vol. Several specific remarks about PETN are contained in that article. The industrial nitration of PE differs from most nitrate esters in that it employs coned nitric acid rather than mixed acid. Nevertheless nitration via the nitronium ion mechanism, which is the preferred mechanism in mixed acid nitrations, is also feasible in coned nitric acid. However, Eremenko and co-workers claim that the nitrating agent in PE nitrations, in mixed acid, is unionized nitric acid (Refs 39 76). The present writer does not find Eremenko s arguments to be very convincing. In any case, commercial production of PETN employs nitric acid and not the mixed acids of Eremenko s studies... 

A group of flavoenzyme reductases mediate the reduction both nitrate esters and C= C double bonds generally activated with carbonyl or nitro functions. The structures of the substrates vary widely (references in Faber 1997). 

Feuer and co-workers ° conducted extensive studies into alkaline nitration with nitrate esters, exploring the effect of base, time, stoichiometry, concentration, solvent, and temperature on yields and purity. Reactions are generally successful when the substrate a-proton acidity is in the 18-25 p A a range. Alkoxide bases derived from simple primary and secondary aliphatic alcohols are generally not considered compatible in reactions using alkyl nitrates. Optimum conditions for many of these reactions use potassium tert-butoxide and amyl nitrate in THF at —30 °C, although in many cases potassium amide in liquid ammonia at —33 °C works equally well. 

The scope of these reactions is illustrated by the variety of functionalized nitrate esters which can be prepared (Table 3.1). In general, primary and secondary alkyl iodides and bromides... 

Voelter and co-workers synthesized the nitrate esters of some carbohydrates by treating the corresponding trifluoromethanesulfonate (triflate) esters with tetrabutylammonium nitrate. Yields were generally excellent. The same authors describe a one-pot process for the synthesis... 

The nitro substituents are generally classihed according to the nature of the atom to which they are attached carbon, nitrogen or oxygen. - Accordingly, in the previous chapters, the introduction of C-nitro, iV-nitro (nitramine) and O-nitro (nitrate ester) functionality into organic compounds has been discussed. 

Chemical Properties NG reacts chemically as a nitrate ester, saponifiable to glycerol by alka-lies (preferably with peroxide present), and hydrolyzed by nitric acid to glycerol. In general, side products tend (d be produced resulting from cleavage of the C—C bonds and oxidation of the alcohol functions... 

Nitroxyethyl Nitramine Plasticizers Nitroxy ethyl nitramine (NENA) plasticizers are a new family of energetic plasticizers which have emerged recently. These are effective plasticizers in energetic formulations, particularly in nitrocellulosic systems. NENAs contain both nitrate ester and nitramine functionalities and possess the general structure RN (N02).CH2.CH2.0N02 where R is methyl, ethyl, propyl, isopropyl, butyl and pentyl. 

Nitrotoluenes, Van No strand, NY(1918) 2)M.Kostevitch, "Tarry Matter of Alpha Trinitrotoluene, Part II, Imprd Art Vol-taire,P aris( 1927), 8 3)Sidgwick( 19 37), 259 et seq 4)Davis(1943), 136-7, 147, 149-51 170-1 5>negering( 1950), 139 seq 6) Dept of the Army TM 9-1910( 1955), 146 Alkalies, Action on Nitric Esters. Organic nitrates in general are readily saponified by alkaline solns. A simple metathetical reaction to yield the alkali nitrate and alcohol does not take place instead, as a result of simultaneous oxidation and reduction, alkali nitrite and a variety of products are formed depending on the conditions of the reaction. The resistance of different nitric esters to alkalies varies considerably. Thus, starch nitrate is decomposed much more slowly than cellulose nitrate and amylopectin nitrate still more alowly... 

We said esters are condensation products between carboxylic acids and alcohols, but this definition is really too restrictive. In the most general sense, an ester is the condensation product between an alcohol and an acid, not just a carboxylic acid. We saw an example of a nitrate ester earlier in the structure of nitroglycerin. In biochemistry, phosphate esters are one of the most important classes of esters. A phosphate ester is derived from an alcohol and phosphoric acid (H3P04). Again, the acid and alcohol are condensed (under special reaction conditions) to give the ester and a molecule of water. This is shown in Figure 11.53. Phosphate esters form the backbone of DNA and RNA. 

The propellants derived from nitrate ester-based binders possessed the undesirable characteristics associated with nitrate ester groups such as thermal instability, hydrolytic instability, and impact instability (especially for highly nitrated compositions). For this reason a study was undertaken to prepare polymeric binders in which oxygen is carried in the form of the more thermally and hydrolytically stable nitro group. Aerojet General Corp., working with both the Purdue and the Ohio Research Foundations, carried out the bulk of these studies. The following are typical of the condensation monomers synthesized by Aerojet ... 

---