Peracetic acid, epoxidation with

Construction of the simplest fused heterocyclic system that shows some anabolic activity starts by epoxidation of the olefin at C2 in 23-1 with peracetic acid buffered with sodium acetate (23-2) (Scheme 5.23). Reaction of this intermediate with potassium thiocyanate and phosphoric acid, essentially thiocyanic acid, leads to diaxial opening of the oxirane to form the 3a-hydroxy-2/8-cyanate 23-3. Treatment of the product with base leads to formation of the /3-thioepoxide 23-5. Formation of that product can be rationalized by assuming that the first step involves removal by base of a proton on the hydroxyl group. That alkoxide then proceeds to add to the cyano group at C2 to form a transient five-membered ring as in... 

Typical of the epoxidized diene polymers are the products produced by treatment of polybutadiene with peracetic acid. Epoxidized diene polymers are not very reactive toward amines but may be cross-linked with acid hardeners. Cured resins have substantially higher heat-distortion temperatures (typically, 250°C) than do the conventional amine-cured diglycidylether resins. 

Epoxidized oils are obtained by treatment of drying and semidrying oils (unsaturated), such as linseed and soybean oils, with peracetic acid. Epoxidized oils find use primarily as plasticizers and stabilizers for PVC. 

NR latex (modified with peracetic acid epoxidation)... 

Medroxyprogesterone acetate (74) is stmcturaHy related to and has been prepared from hydroxyprogesterone (39) (Fig. 10). Formation of the bis-ketal accomplishes the protection of the ketones and the required migration of the double bond. Epoxidation with peracetic acid produces a mixture of epoxides (75), with a predominating. Treatment of the a-epoxide with methyl magnesium bromide results in diaxial opening of the epoxide. Deprotection of the ketones provides (76), which is dehydrated to (77) by treatment with dilute sodium hydroxide in pyridine. Upon treatment with gaseous hydrochloric... 

Dieldrin [60-57-1] or l,2,3,4,10,10-hexachloro-l,4,4t ,5,8,8t -hexahydro-6,7-epoxy-l,4- <7o, Aro-5,8-dimethanonaphthalene (34) (mp 176°C, vp 0.4 mPa at 20°C) is formed from aldrin by epoxidation with peracetic or perben2oic acids. It is soluble in water to 27 / g/L. Aldrin and dieldrin have had extensive use as soil insecticides and for seed treatments. Dieldrin, which is very persistent, has had wide use to control migratory locusts, as a residual spray to control the Anopheles vectors of malaria, and to control tsetse flies. Because of environmental persistence and propensity for bio accumulation, registrations in the United States were canceled in 1974. 

Specialty Epoxy Resins. In addition to bisphenol, other polyols such as aUphatic glycols and novolaks are used to produce specialty resins. Epoxy resins may also include compounds based on aUphatic, cycloaUphatic, aromatic, and heterocycHc backbones. Glycidylation of active hydrogen-containing stmctures with epichlorohydrin and epoxidation of olefins with peracetic acid remain the important commercial procedures for introducing the oxirane group into various precursors of epoxy resins. 

Cycloaliphatic Epoxy Resins. This family of aUphatic, low viscosity epoxy resins consists of two principal varieties, cycloolefins epoxidized with peracetic acid and diglycidyl esters of cycHc dicarboxyhc acids. 

Epoxidation of the A -enol acetate was originally carried out with per-benzoic acid. Monoperphthalic acid has also been used, but is apparently more susceptible to steric and conformational factors. The commercially available peracetic acid is generally most convenient. Based on the expected backside attack, the derived epoxides have the 17a configuration, and hydrolysis always produces the 17a-hydroxy group. 

Hydrolysis of the intermediate epoxy acetate is generally carried out with strong alkali if base-sensitive groups are present, milder conditions (e.g., potassium bicarbonate, potassium carbonate) can be employed. If commercial peracetic acid (which contains sulfuric acid) is used for epoxidation, the intermediate epoxy acetate cannot be isolated, but is hydrolyzed in situ by the acid to the desired ketol. Acid hydrolysis will also retain 3-acetates, if present. ... 

The second important process for propylene oxide is epoxidation with peroxides. Many hydroperoxides have been used as oxygen carriers for this reaction. Examples are t-butylhydroperoxide, ethylbenzene hydroperoxide, and peracetic acid. An important advantage of the process is that the coproducts from epoxidation have appreciable economic values. 

The monomer (laurolactam) could he produced from 1,5,9-cyclododeca-triene, a trimer of hutadiene (Chapter 9). The trimer is epoxidized with peracetic acid or acetaldehyde peracetate and then hydrogenated. The saturated epoxide is rearranged to the ketone with Mgl2 at 100°C. is then changed to the oxime and rearranged to laurolactam. 

Stack and coworkers immobilized phenantrohne derivative 16 on micelle-templated silica SBA-15 (Scheme 8) [55,56]. The system showed more selective and efficient catalytic activity for olefin epoxidations with peracetic acid than the analogous homogeneous catalyst. 

Endrin is a stereoisomer of dieldrin produced by the reaction of vinyl chloride and hexachloro-cyclopentadiene to yield a product which is then dehydrochlorinated and condensed with cyclopentadiene to produce isodrin. This intermediate is then epoxidized with peracetic or perbenzoic acid to yield endrin. An alternative production method involves condensation of hexachlorocyclopentadiene with acetylene to yield the intermediate for condensation with cyclopentadiene (EPA 1985e IARC 1974). 

The epoxidation of fatty acid methyl esters (FAME) is traditionally conducted in strong acidic media, e.g., with peracetic acid in sulfuric acid solutions. These reactions can be conducted by an environmentally benign route, however, in the... 

Another method of making epoxides is the electrophilic reaction of alkenes with a peroxy acid such as peroxyacetic acid (sometimes simply peracetic acid). Thus, cyclohexene may be converted into the epoxide in a single reaction. 

Emulsion, minimizing of, 37, 31 Enanthaldehyde, 34, 51 ENANTHALDEHYDE, e-METHYL-d-OXO-, dimethyl acetal, 32, 79 Enanthic acid, e-oxo, 31, 3 Epichlorohydnn, 31, 1 Epoxidation of fra j-stilbene with peracetic acid, 38,83 a,a -EpOXYBIBENZYL, 38, 83 Esterification, by azeotropic distillation with toluene, 30, 30, 31 of coumalic acid with methanol, 36,44 of diethoxyacetic acid, 35, 59 of ethanol with phosphorus trichloride, 31, 111... 

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