1 - ethanone, oxidation

I-[2- 3-Methyl-2-triazenyl)phenyl ethanone -oxide, 9CI. IG80... 

After the initial claim of the synthesis of an oxirene (by the oxidation of propyne Section 5.05.6.3.1) this system reappeared with the claim 31LA(490)20l) that 2-chloro-l,2-diphenyl-ethanone (110) reacted with sodium methoxide to give diphenyloxirene (111), but it was later shown (52JA2082) that the product was the prosaic methoxy ketone (112 Scheme 97) (the formation of 111 from 110 would be an a-elimination carbene-type reaction). Even with strong, nonnucleophilic bases, (110) failed to provide evidence of diphenyloxirene formation (64JA4866). 

A -(2,3>5-Trichloro-4-oxocyclohexa-2,5-dienylidene)benzenesulfonamide oxidations of 5,6-dihydro-l,3-thiazines 24 afford excellent yields of l-(4-ethoxy-2,6-diaryl-277-l,3-thiazin-5-yl)ethanone 58 and 59 (Equation 6) <2000CHE862>. 

In the original patent published by Merck in 1995, rofecoxib (2) was synthesized in three steps from the known 4-(methylthio)acetophenone (10), prepared from the Friedel-Crafts acylation of thioanisole. As depicted in Scheme 2, oxidation of sulfide 10 using an excess of magnesium monoperoxyphthalate hexahydrate (MMPP, an inexpensive, safe and commercially available surrogate for w-CPBA) gave rise to sulfone 11, which was subsequently brominated with bromine and AICI3 to afford 2-bromo-l-(4-(methylsulfonyl)phenyl)ethanone (12). After recrystallization from 1 1 EtOAc/hexane, the pure phenylacyl bromide 12 was then cyclo-condensed with phenylacetic acid under the influence of l,8-diazabicyclo[5.4.0]undec-7-ene (DBU) to deliver rofecoxib (2) in... 

Another synthetic route starts with the condensation of N-methoxyamide (x) with 4-(methylsulfanyl) benzyl-magnesium bromide to give 1-(6-methylpyridin-3-yl)-2-(4-(methylsulfanyl)phenyl)ethanone (xiii), which is finally oxidized with the wolframate to ketosulfone (ix). 

To retain a side-chain substituent, selective methods of oxidation are required. For example, 4-methylbenzoic acid can be prepared from l-(4-methylphenyl)-ethanone by the haloform reaction (Section 17-2B) ... 

Nitrile oxides react with the methyl enol ethers of (Rs)-l -fluoro-alkyl-2-(p-tolylsulfinyl)ethanones to produce (45,5/f,/fs)-4,5-dihydroisoxazoles with high regio-and diastereo-selectivity.87 In the 1,3-dipolar cycloaddition of benzonitrile oxide with adamantane-2-thiones and 2-methyleneadamantanes, the favoured approach is syn, as predicted by the Cieplak s transition-state hyperconjugation model.88 The 1,3-dipolar cycloaddition reaction of acetonitrile oxide with bicyclo[2.2.l]hepta-2,5-diene yields two 1 1 adducts and four of six possible 2 1 adducts.89 Moderate catalytic efficiency, ligand acceleration effect, and concentration effect have been observed in the magnesium ion-mediated 1,3-dipolar cycloadditions of stable mesitonitrile oxide to allylic alcohols.90 The cycloaddition reactions of acryloyl derivatives of the Rebek imide benzoxazole with nitrile oxides are very stereoselective but show reaction rates and regioselectivities comparable to simple achiral models.91. 

However, the oxidation of 1-methyl-1-cyclohexene, having a substituent in position 1 (entry 8), proceeds much less selectively, providing only 44% of a cyclic ketone in the reaction products. The reaction is accompanied by a significant cleavage of double bonds leading to 1-cyclopentyl-ethanone and 6-hepten-l-one. An aldehyde (C7H120) is also found in the reaction products ( 2-3%). 

In [210, 211] the solid-phase reaction of unsaturated ketones and anilines on a surface of silica gel in the presence of indium chloride under microwave irradiation was described. The library consists of 15 quinolines in yields of 55-87% which were generated quickly and characterized. Ranu et al. [211] showed that dihydro derivatives of qiunolines (e.g., 270 and 273) can also be synthesized, but in this case one component of the reaction must be a 4,4-disubstituted methyl vinyl ketone, for example, mesityl oxide 52 or l-(2-methylcyclopent-l-enyl)ethanone 272 (Scheme 3.75). 

Dimethyl-1-cyclohexyl-1-trimethylsiloxy-ethene (191) gives by means of methyllithium/ethylbromide in dimethoxyethane (DME) 1-cyclohexyl-2,2-dimethyl-1-butanone (297)133 Dimerizations occur when substances such as 1-trimethylsiloxy-styrene (192) or 1-trimethylsiloxy-l-cyclopentene (195) are treated with silver oxide/ DMSO to afford l,5-diphenyl-2,5-butadione (198) and 2,2 -dicyclopentanonyl (199)l34 respectively. Under the catalytic influence of Cu2+ ions, 192 plus ben-zenesulfonyl chloride yield phenyl-(l-phenyl-l-ethanone-2-yl)sulfone (200)l3 ... 

Compound 1295 undergoes a smooth reaction in boiling THE to produce triphenylphosphine oxide and l-(tri-fluoromethyl)-3/f-pyrrolizines 1296 that may be considered as a product of an intramolecular Wittig reaction (Scheme 247) <2006ARK55>. The tautomeric l//-pyrrolizine 1297 was not formed. When phosphorus ylides containing the trichloromethyl group 1298 were heated in THE the expected pyrrolizine 1299 was not formed, and the 2,2,2-trichloro-l-(l//-pyrrol-2-yl)ethanone 1300, dialkyl 2-butynedioate and triphenylphosphine were obtained instead (Scheme 248). 

C6H5BrOS 1 -(5-bromo-2-thienyl)ethanone 5370-25-2 25.00 1.6489 2 6836 C6H5N03 isonicotinic acid N-oxide 13602-12-5 53.33 1.3510 2... 

The synthesis began with the condensation of 4-bromo-l,2-diaminobenzene with 2-bromo-l-(4-(dimethylamino)phenyl)ethanone to provide two separable isomeric products. The products were crystallized and examined by X-ray crystallography to confirm the structures. The desired product was the major compound isolated at 36.7% yield. Formation of the aryl tributyltin was accomplished under a standard Stille coupling procedure, followed by conversion to the isotopically-enriched iodine under acidic oxidizing conditions to provide one of the desired isotopically-labelled drags needed for the monitoring of the Alzeheimer s patients. 

The A -hydroxyphthalimide (NHPI)-catalysed liquid-phase oxidation of 1-methoxy-4-(l-methylethyl)benzene (G) with O2 produced 1-methyl-l-(4-methoxyphenyl)ethyl hydroperoxide in a yield of 73 mol%. However, when (G) was oxidized in the presence of NHPI in combination with Cu(II), the product l-(4-methoxyphenyl)ethanone was produced with high selectivity up to 68-75mol% but in low yield (llmol%). The use of NHPI in combination with Co(II), Mn(II), and Fe(II) salts, and the effects of the catalyst concentration and the temperature was studied. ... 

Zawadiak et al. [620] studied the retention of three oxidation products of 2-isopropylnaphthalene (IPN), l-(2-naphthyl)ethanone, 2-(2-naphthyI)-2-propanol,... 

The ethanone bridge in products such as 84 and 86 could be oxidatively cleaved after hydroxylation a to the ketone. Conditions were found for in situ or-hydroxylation of the enolate resulting from the Brook-then-Cope sequence. For example, the union of sodium enolate 87 and cc,P-... 

Diverse dihydronaphtho[l,2-(r]furans were generated fix)m 1,4-naphthoquinones and olefins in the presence of ceric ammonium nitrate (13OBC6097). ( )-Lantalucratins A and B were produced in the presence of diammonium cerium(IV) nitrate (13T10470).Benzo[(>]furan moieties were synthesized by a three-component Mannich reaction of 3-acetyl-2H-chromen-2-one or l-(l-benzo[fc]fioran-2-yl) ethanone with p-substituted aromatic aldehydes and aromatic amines with ceric ammonium nitrate (CAN) as a catalyst (13MCR4787).p-Alkenylphenols went through the oxidative dimerization to generate substituted dihydrobenzo[l)]furans in the presence of CAN (13T653). 

Disubstituted isocoumarins arise from the copper(II)-catalyzed addition of o-halobenzoic acids to active internal alkynes (13JOC1660), rhodium(III)-mediated oxidative coupling ofbenzoic acids with disubsti-tuted alkynes (13T4454), palladium(II)-catalyzed tandem annulation reaction of o-alkynylbenzoates with methyl vinyl ketone (13T8626), and nickel(II)-promoted t-butyl isocyanide insertion in 2-(o-bromophenyl)-1-ethanones followed by hydrolysis (Scheme 69) (13SC3262). 

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