Nitro epoxide

Nitro. substitution at the epoxide ring enhances the reactivity, as demonstrated by the relatively easy formation of 14 from the a-nitro epoxide 13. ... 

Sodium borohydride (NaBH4), a relatively mild reducing agent, reduces epoxides only sluggishly except for nitro epoxides. In the mixed solvent f-butyl alcohol and methanol, sodium borohydride can reduce aryl-substituted epoxides, terminal epoxides and cyclohexene oxide, to the corresponding alco-hols. The regiochemistry of this reaction is nearly the same as that with LAH. For example the reduc-... 

Kim, D.Y, and Kong, M., A new synthesis of cyclic P-keto phosphonates from a-nitro epoxides and a dialkyl phosphite, J. Chem. Soc., Perkin Trans. 1, 3359, 1994. 

Catalytic reduction of the nitro-epoxide (8.1, R = COOMe) leads directly to the indole carboxylic ester but when R = H, reduction of the nitro-epoxide does not give the indole. However, cleavage of the epoxide and reduction of the nitro group gives the amine (8.2) which is cyclized by a strong base. 

Cyclic p-keto phosphonates. A new synthesis involves the treatment of a-nitro epoxides with diethyl phosphite and a base at room temperature. 

Reaction of 1,2-anhydro-3i4.J 5,6-di-0-isopropylidene-1-C-nitro-D-mannltol with potassium hydrogen difluoride in anhydrous ethylene glycol yielded 2-deoxy-2-fluoro-D-glucose minor by-products arise by epimerization at C-2 of the initially formed fluoro-aldehyde, and by attack of solvent at C-2 of the intermediate nitro-epoxide. Part of... 

Glyceryl ethers are formed by the reaction of an epoxide compound with an organic hydroxyl compound as seen in Figure 8.1. The epoxide compounds, which can be used for this reaction, include alkylene oxides, epihalohydrins, nitro epoxide compounds, epoxide ethers, and epoxide thioethers. There are many types of hydroxyl compounds that can be used the most used in industry includes primary alcohols, ethoxylated alcohols, and branched alcohols. The types of catalyst used for this reaction include acid acting compounds and metal halides such as sulfuric acid and stannic chloride, respectively. ... 

A new method of preparing deoxy-sugar derivatives involves treatment of a-nitro-epoxides with sodium borohydride in this way, for example, compound (1) gives the 5-deoxy derivative (2), and (3) gives (4). However,... 

The unsaturated nitro-peroxy compound 53 reacts with nucleophiles at the 4-position to produce branched-nitro-epoxides 54 [R = D, 4-MeC6H4S, CH(Ac)2]. The synthesis of a thromboxane B2 precursor from an intermediate C-4-carboxyamidomethyl derivative is covered in Chapter 24 and the preparation of 1 - 4-carbon linked di- and tri-saccharides is mentioned in Chapter 3. 

In general, peroxomonosulfates have fewer uses in organic chemistry than peroxodisulfates. However, the triple salt is used for oxidizing ketones (qv) to dioxiranes (7) (71,72), which in turn are useful oxidants in organic chemistry. Acetone in water is oxidized by triple salt to dimethyldioxirane, which in turn oxidizes alkenes to epoxides, polycycHc aromatic hydrocarbons to oxides and diones, amines to nitro compounds, sulfides to sulfoxides, phosphines to phosphine oxides, and alkanes to alcohols or carbonyl compounds. 

Obsolete uses of urea peroxohydrate, as a convenient source of aqueous hydrogen peroxide, include the chemical deburring of metals, as a topical disinfectant and mouth wash, and as a hairdresser s bleach. In the 1990s the compound has been studied as a laboratory oxidant in organic chemistry (99,100). It effects epoxidation, the Baeyer-Villiger reaction, oxidation of aromatic amines to nitro compounds, and the conversion of sodium and nitrogen compounds to S—O and N—O compounds. 

Other methods of generating a-aminoketones in situ are common, if somewhat less general than the methods already described. 2-Nitrovinylpyrrolidine, which is readily available, yields 2,3-bis(3-aminopropyl)pyrazine on reduction and this almost certainly involves ring opening of the intermediate enamine to an a-aminoketone which then dimerizes under the reaction conditions (Scheme 59) (78TL2217). Nitroethylene derivatives have also served as a-aminoketone precursors via ammonolysis of the derived epoxides at elevated temperatures (Scheme 60) (76S53). Condensation of 1,1-disubstituted hydrazine derivatives with a-nitro-/3-ethoxyethylene derivatives has been used in the synthesis of l,4-dialkylamino-l,4-dihydropyrazines (Scheme 61) (77S136). 

In another study that appeared prior to the advent of CASTing, the traditional combination of epPCR and DNA shuffling was used to enhance the enantioselectivity of the hydrolytic kinetic resolution of p-nitro phenyl glycidyl ether and other epoxides catalyzed by the EH from Agrobacterium radiobacter [59]. Several mutants were obtained with up to 13-fold improved enantioselectivity. The amino acid exchanges took place around the active site. 

It is interesting to note the chemoselectivity of the reaction double and triple bonds, thioketals, epoxides, nitro and sulfone groups and usual functions are not affected. 

Another method involves treatment with Lawesson s reagent (see 16-10). When epoxides are substrates, the products are 3-hydroxy thiols. Tertiary nitro compounds give thiols (RNO2 RSH) when treated with sulfur and sodium sulfide, followed by amalgamated aluminum. 

Epoxidation of substituted spiro[cyclopentane-l,9 -fluorene]-2-enes 68 with a peroxidic reagent was studied [98], The spiro olefins react with m-chloroperbenzoic acid (mCPBA) in chloroform at 3 °C to give a mixture of the epoxides. In all cases (2-nitro (68b), 4-nitro (68c), 2-fluoro (68d) and 2-methoxyl (68e) groups), the iyn-epoxides, i.e., the syn addition of the peroxidic reagent with respect to the substituent, is favored. For example, for 6 nsyn anti = 63 31 for 68c syn anti = 65 35. Thus, a similar bias is observed in both the reduction of the carbonyl derivatives of 30 and the epoxidation of the derivatives of 68. 

The diastereomeric excess (d.e.) of 76a reached 72% (epoxidation) and 98% (dihydroxylation). Nitro substitution on the aromatic ring (as in 77a) significantly reduced the selectivity (increased the syn proportion), although anti preference was stiU retained in epoxidation (20% d.e.) and in dihydroxylation (68% d.e.). 

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