Organic Chemistry of Explosives

98 Synthetic Routes to Nitrate Esters

give excellent yields of the corresponding nitrate ester. Allylic, benzylic and tertiary chlorides

also give nitrate esters in good yield. The nucleophilic substitution of alkyl halides with silver

nitrate is a very attractive method for the synthesis of some acid-sensitive nitrate esters, like

glycidyl nitrate, which is prepared in 72 % yield from the reaction of epibromohydrin with

silver nitrate (Table 3.1, Entry 4).^62 The direct nitration of glycidol with nitric acid or mixed

acid is not possible due to acid-catalyzed ring opening of the epoxide functionality. Russian

chemists^64 ,^65 have reported the synthesis of energetic hemiformal nitrates from the metathesis

of the corresponding chloromethyl ethers with silver nitrate (Table 3.1, Entries 6 and 7).

R --- O H

Ph 3 P, I 2 , Imidazole AgNO 3

Et 2 O, CH 3 CN

[ R I ] R --- O N O 2 (Eq. 3.8)

Figure 3.17

Tojo and co-workers^69 reported a ‘one-pot’ synthesis of alkyl nitrates from alcohols via the

alkyl iodide; the alcohol is treated with a mixture of iodine, triphenylphosphine and imidazole

in diethyl ether–acetonitrile, and the resulting alkyl iodide is reactedin situwith silver nitrate

(Equation 3.8). Reported yields for primary alcohols are good to excellent but yields are lower

for secondary alcohols.

3.3.2 Decomposition of nitratocarbonates

RO Cl

O

AgNO 3

RO ONO 2

O

+ RONO 2 CO 2 AgCl

C 5 H 5 N, CH 3 CN

+

29

+

Figure 3.18

An extremely mild method for the synthesis of nitrate esters from easily oxidized or acid-

sensitive alcohols involves the decomposition of a nitratocarbonate (29).^70 ,^71 The nitratocar-

bonate is preparedin situfrom 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 ni-

trate ester and carbon dioxide. Few examples of these reactions are available in the literature^70 ,^71

and they are limited to a laboratory scale.

3.3.3 Displacement of sulfonate esters with nitrate anion

Voelter and co-workers^72 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