Epoxides nitrate

Epoxides are normally hydrogenated in preference to saturated ketones but double bonds are usually reduced under these conditions. It is possible in some cases to selectively cleave an epoxide without saturating double bonds by the use of the deactivated catalysts recommended for the partial reduction of acetylenes (see section IV) or by the addition of silver nitrate to the palladium-catalyzed reaction mixture. " ... 

Finally, epoxides can be converted into other functional groups under certain well-defined conditions. For example, ceric ammonium nitrate (CAN) catalyzes the efficient conversion of epoxides to thiiranes (i.e., 124 125) at room temperature in te/t-butanol <96SYN821>. 

Products formed by reaction of NO3 radicals with a-pinene have been identified and include pinane epoxide, 2-hydroxypinane-3-nitrate, and 3-ketopinan-2-nitrate formed by reactions at the double bond, and pinonaldehyde that is produced by ring fission between C-2 and C-3 (Wangberg et al. 1997). These reactions should be viewed in the general context of odd nitrogen to which alkyl nitrates belong (Schneider et al. 1998). 

The catalysts which have been tested for the direct epoxidation include (i) supported metal catalysts, (ii) supported metal oxide catalysts (iii) lithium nitrate salt, and (iv) metal complexes (1-5). Rh/Al203 has been identified to be one of the most active supported metal catalysts for epoxidation (2). Although epoxidation over supported metal catalysts provides a desirable and simple approach for PO synthesis, PO selectivity generally decreases with propylene conversion and yield is generally below 50%. Further improvement of supported metal catalysts for propylene epoxidation relies not only on catalyst screening but also fundamental understanding of the epoxidation mechanism. 

Urbanski, 1965, Vol. 2, 129 Shock-sensitive and explodes at 200° C. See related ALKYL NITRATES, 1,2-EPOXIDES... 

Reaction with epoxides gives the dangerously unstable and explosive mixed nitrate-perchlorate diesters, such as 1,2-ethanediyl nitrate perchlorate from ethylene oxide. 

However, styrene and cyclohexene gave complex product mixtures, and 1-octene did not react under the same reaction conditions. Thus, the activity of this catalyst is intrinsically low. Jacobs and co-workers [159,160] applied Veturello s catalyst [PO WCKOj ]3- (tethered on a commercial nitrate-form resin with alkylammonium cations) to the epoxidation of allylic alcohols and terpenes. The regio- and diastereoselectivity of the parent homogeneous catalysts were preserved in the supported catalyst. For bulky alkenes, the reactivity of the POM catalyst was superior to that of Ti-based catalysts with large pore sizes such as Ti-p and Ti-MCM-48. The catalytic activity of the recycled catalyst was completely maintained after several cycles and the filtrate was catalytically inactive, indicating that the observed catalysis is truly heterogeneous in nature. 

Nitroaniline Nitric acid, Sulfuric acid, 2314 Nitronium perchlorate, 1,2-Epoxides, 4028 2.2 -Oxybis(ethyl nitrate), 3260 Sodium nitrate, Phenol, Trifluoroacetic acid, 4721 See also NITRATING AGENTS... 

Synthesis of vicinal dInItrate esters from the ring opening nitration of epoxides with dinitrogen pentoxide (Ref. 75) ... 

Research efforts are ongoing into the use of dinitrogen pentoxide for the industrial synthesis of nitrated hydroxy-terminated polybutadiene (NHTPB) from epoxidated HTPB (Section 3.10). The reaction of aziridines with dinitrogen pentoxide is an important route to 1,2-nitramine-niU ates and these reactions are discussed in Section 5.8.1. ... 

Reaction of epoxides with nitrate anion under acidic conditions... 

Nichols and co-workersstudied the formation of j8-hydroxy nitrate esters via the acid-catalyzed ring-opening of epoxides with nitrate anion. Reactions were conducted in aqueous media using solutions of ammonium nitrate is nitric acid and under nonaqueous conditions using solutions of pure nitric acid in chloroform. 2-Nitratoethanol (32) is formed in 58 % yield from ethylene oxide (30) using either of these methods. ... 

Unsymmetrical epoxides (39) can form two isomers, (40) and (41), on reaction with nitrate anion and so raise the issue of regioselectivity. Under acidic conditions terminal epoxides are found to predominantly yield the primary nitrate ester (41) although this is not clear cut and propylene oxide is reported to yield an ill defined mixture of isomers. A comprehensive study on the regioselectivity of epoxide opening with nitrate anion under acidic conditions was conducted on glycidol. ... 

Single electron transfer nitration of epoxides with ceric ammonium nitrate... 

A suspension of thallium (III) nitrate in hexane reacts with epoxides to give the corresponding -hydroxy nitrate esters in good yield. The same reagent in acetonitrile has been used to synthesize a-nitratoketones from substituted acetophenones, 1,2-dinitrate esters from alkenes, and 1,3-dinitrates from ring-opening nitration of cyclopropanes. ... 

The use of oxetanes for the synthesis of polynitrate esters is generally of less value than the use of epoxides, which are readily available from the epoxidation of alkenes. The analogous reaction of azetidines with dinitrogen pentoxide is a route to 1,3-nitramine-nitrates and these reactions are discussed in Section 5.8.2. ... 

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