Nitrate ester preparation

Nitrate Esters Prepared by the Procedure of Caesar and Goldfranh ... 

Esters of nitro alcohols with primary alcohol groups can be prepared from the nitro alcohol and an organic acid, but nitro alcohols with secondary alcohol groups can be esterified only through the use of an acid chloride or anhydride. The nitrate esters of the nitro alcohols are obtained easily by treatment with nitric acid (qv). The resulting products have explosive properties but are not used commercially. 

Dimethoxybenzyl esters prepared from the acid chloride and the benzyl alcohol are readily cleaved oxidatively by DDQ (CH2CI2, H2O, rt, 18 h, 90-95% yield). A 4-methoxybenzyl ester was found not to be cleaved by DDQ. The authors have also explored the oxidative cleavage (ceric ammonium nitrate, CH3CN, H2O, 0°, 4 h, 65-97% yield) of a variety of 4-hydroxy- and 4-amino-substituted phenolic esters. ... 

Solutions of acetyl nitrate, prepared from fuming nitric acid and acetic anhydride, can react with alkenes to yield a mixture of nitro and nitrate ester products, but the /3-nitroacetate is usually the major product. ° Treatment of cyclohexene with this reagent is reported to yield a mixture of 2-nitrocyclohexanol nitrate, 2-nitrocyclohexanol acetate, 2-nitrocyclohexene and 3-nitrocyclohexene. °/3-Nitroacetates readily undergo elimination to the a-nitroalkenes on heating with potassium bicarbonate. /3-Nitroacetates are also reduced to the nitroalkane on treatment with sodium borohydride in DMSO. ... 

An interesting example of the effectiveness of different reagents for 0-nitration can be seen during the synthesis of neo-inositol-based nitrate ester explosives. l,4-Dideoxy-l,4-dinitro-neo-inositol (15), a compound readily prepared from the condensation of nitromethane and glyoxal in the presence of base,undergoes conversion to the tetranitrate ester (16) on... 

Olah and co-workers ° conducted a comprehensive study into the use of N-nitropyridinium salts for nitration. Such salts are easily prepared from the slow addition of the appropriate heterocyclic base to an equimolar suspension of nitronium tetrafluoroborate in acetonitrile. Olah studied the effect on nitration of changing both the structure of the heterocyclic base and the counter ion. Three of these salts (20, 21, 22) illustrated above have been synthesized and used for the 0-nitration of alcohols with success. Transfer nitrations with Al-nitropyridinium salts are particularly useful for the preparation of nitrate esters from acid-sensitive alcohols and polyols because conditions are essentially neutral. 

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... 

An extremely mild method for the synthesis of nitrate esters from easily oxidized or acid-sensitive alcohols involves the decomposition of a nitratocarbonate (29). The nitratocar-bonate is prepared in situ from metathesis between a chloroformate (reaction between phosgene and an alcohol) and silver nitrate in acetonitrile in the presence of pyridine at room temperature. Under these conditions the nitratocarbonate readily decomposes to yield the corresponding nitrate ester and carbon dioxide. Few examples of these reactions are available in the literature and they are limited to a laboratory scale. 

Solutions of nitric acid in chlorinated solvents can add to some alkenes to give nitrate esters. Some tertiary nitrate esters can be prepared in this way isobutylene (49) reacts with fuming nitric acid of 98.6 % concentration in methylene chloride to give ferf-butyl nitrate (50). However, the products obtained depend on both the substrate and the reaction conditions /3-nitro-nitrate esters, vic-dinitrate esters, /3-nitroalcohols and nitroalkenes have been reported as products with other alkenes. Oxidation products like carboxylic acids are also common, especially at elevated temperatures and in the presence of oxygen. The reaction of alkenes with fuming nitric acid is an important route to unsaturated nitrosteroids, which assumedly arise from the dehydration of /3-nitroalcohols or the elimination of nitric acid from /3-nitro-nitrate... 

Barton and Narang" have prepared nitrate esters by treating primary and secondary alky-lamines with dinitrogen tetroxide in the presence of an amidine base like DBU. Wudl and Lee " conducted deamination reactions without any amidine base and reported much lower yields of nitrate ester product. The use of an amidine base is not necessary if the amine substrate... 

A number of secondary high explosives containing both nitramine and nitrate ester functionality have been reported. Aliphatic examples include A-nitrodiethanolamine dinitrate (DINA) (110), prepared from the nitration of diethanolamine with nitric acid-acetic anhydride in the presence of zinc chloride,and A,A -dinitro-A,A -bis(2-hydroxyethyl)oxamide dinitrate (NENO) (111), prepared from the mixed acid nitration of A,lV -bis(2-hydroxyethyl) oxamide . 

Agrawal and co-workers prepared some energetic explosives containing nitrate ester, nitramine and aromatic C-nitro functionality within the same molecule and studied their thermal and explosive properties l-(2-nitroxyethylnitramino)-2,4,6-trinitrobenzene... 

Alkyl lV,lV-dinitramines (154) have been prepared from the reaction of the tetraalkylam-monium salts (155) of primary nitramines with nitryl fluoride in acetonitrile at subambient temperature. The same reaction with the primary nitramine or its alkali metal salts yields the corresponding nitrate ester. Treatment of the ammonium, potassium, or lithium salts of primary nitramines (156) with a solution of nitronium tetrafluoroborate in acetonitrile at subambient temperature yield alkyl iV,iV-dinitramines. ° The same reactions in ether or ester solvents enables the free nitramine to be used. The nitrolysis of A-alkylnitramides (157) and N,N-diacylamines with nitronium tetrafluoroborate in acetonitrile, and the nitration of aliphatic isocyanates with nitronium tetrafluoroborate and nitric acid in acetonitrile, also yield alkyl A,A-dinitramines (154). 

Alkyl azides are conveniently prepared from the reaction of alkali metal azides with an alkyl halide, tosylate, mesylate, nitrate ester or any other alkyl derivative containing a good leaving group. Reactions usually work well for primary and secondary alkyl substrates and are best conducted in polar aprotic solvents like DMF and DMSO. The synthesis and chemistry of azido compounds is the subject of a functional group series. ... 

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