Methyl ketones from ester

Carboxylic acid esters from methyl ketones... 

From a comparison of the types of end group in Table IV which give vapour-or liquid-expanded films, it appears that those compounds whose end groups possess a considerable amount of residual affinity, such as undissociated fatty acids, amides, nitriles, c., form liquid-expanded films those which have less, such as esters or methyl ketones, form vapour-expanded. The lateral adhesion between the end groups therefore appears to have a controlling influence in 1 J.C.S. (1926), 2491 (1931), 1533. 

Figure 3.62 Iron (II) activation of hydrogen peroxide to produce ring-opened methyl esters from cyclic ketones.

Lithium enolates derived from methyl ketones and acetates successfully add to vinyl selenoxides - and to vinyl selenones to give cyclopropyl ketones and esters (Scheme 110). The a-lithioalkyl selenoxide or selenone intermediates presumably exchange to the lithium enolates which, after displacement of the seleno or selenoxy group, lead to the observed products. 

From oxiho-Hydroxyaraldehydes and Bis(methylthio)methylidene-Ketones In a route which certainly involves formation of the ester linkage as a hrst step, ortfto-hydroxy-araldehydes react with bis(methylthio)methylidene-ketones (easily generated from methyl ketones by reaction with base, then carbon disulfide, then iodomethane), the ring closure taking place without further intervention. ... 

Substitutions. Enolates generated from methyl ketones on treatment with LDA attack dimethyl 2-bromomethylfumarate in an Sn2 fashion, to give substitued itaconic esters. ... 

Fig. 9.1. (A) Chromatogram of a ten

Ketones and esters are required for C-type inks. Types of esters are ethyl acetate, isopropyl acetate, normal propyl acetate, and butyl acetate. From the ketone class, acetone or methyl ethyl ketone (MEK) can be used. The usual solvent for D-type inks are mixtures of an alcohol, such as ethyl alcohol or isopropyl alcohol, with either aUphatic or aromatic hydrocarbons. Commonly used mixtures are 50/50 blends by volume of alcohol and aUphatic hydrocarbon. 

Garyophyllene. (-)-CaryophyUene can be isolated from Indian turpentine and has been used to prepare a number of woody aroma products. The epoxides are produced by reaction with peracids. Acetylation of caryophyUene also gives a usehil methyl ketone (180) (Fig. 8). Acid-catalyzed rearrangement of caryophyUene in the presence of acetic acid gives a mixture of esters, which are related to caryolan-l-ol and clovan-2-ol (181). 

A thioamide of isonicotinic acid has also shown tuberculostatic activity in the clinic. The additional substitution on the pyridine ring precludes its preparation from simple starting materials. Reaction of ethyl methyl ketone with ethyl oxalate leads to the ester-diketone, 12 (shown as its enol). Condensation of this with cyanoacetamide gives the substituted pyridone, 13, which contains both the ethyl and carboxyl groups in the desired position. The nitrile group is then excised by means of decarboxylative hydrolysis. Treatment of the pyridone (14) with phosphorus oxychloride converts that compound (after exposure to ethanol to take the acid chloride to the ester) to the chloro-pyridine, 15. The halogen is then removed by catalytic reduction (16). The ester at the 4 position is converted to the desired functionality by successive conversion to the amide (17), dehydration to the nitrile (18), and finally addition of hydrogen sulfide. There is thus obtained ethionamide (19)... 

Acylation of ami noketone 8 with the acid chloride from p-toluic acid affords the corresponding ester (10) catalytic hydrogenation leads to the bronchodilator bitolerol (11). An analogous scheme starting from the N-methyl ketone (12) and pivaloyl chloride gives ami noalcohol (14). This compound is then resolved to isolate the levorotatory isomer. There is thus obtained the drug dipivefrin. 

Likewise, thermolysis of 4-azidophenyl methyl ketone in methanol yields 5-acetyl-2-methoxy-3//-azepine (60%), compared to only an 8% yield from the photolytic reaction.78 119 The thermolysis of phenyl azide in refluxing cyclohexanol yields no 3H-azepine, only diphenyl-diazene (10%) and aniline (30%).74 In contrast, thermolysis of methyl 2-azidobenzoate in cyclohexanol furnishes a mixture of methyl 2-(cyclohexyloxy)-3//-azepine-3-carboxylate (20 % bp 127°C/0.1 Torr) and methyl 2-aminobenzoate (60%). Thermolysis of the azido ester in methanol under nitrogen in an autoclave at 150 C yields a 7 10 mixture (by 1HNMR spectroscopy) of the amino ester and methyl 2-methoxy-3//-azepine-3-carboxylate, which proved to be difficult to separate, and much tar.74 The acidic medium179 is probably responsible for the failure of methyl 2-azidoberjzoate to yield a 3//-azepine when thermolyzed in 3-methoxyphenol aniline (40%) is the major product.74... 

Other carbanionic groups, such as acetylide ions, and ions derived from a-methylpyridines have also been used as nucleophiles. A particularly useful nucleophile is the methylsulfinyl carbanion (CH3SOCHJ), the conjugate base of DMSO, since the P-keto sulfoxide produced can easily be reduced to a methyl ketone (p. 549). The methylsulfonyl carbanion (CH3SO2CH2 ), the conjugate base of dimethyl sulfone, behaves similarly, and the product can be similarly reduced. Certain carboxylic esters, acyl halides, and DMF acylate 1,3-dithianes (see 10-10. )2008 Qxj(jatjye hydrolysis with NBS or NCS, a-keto aldehydes or a-... 

Bisulfite addition products are formed from aldehydes, methyl ketones, cyclic ketones (generally seven-membered and smaller rings), a-keto esters, and isocyanates, upon treatment with sodium bisulfite. Most other ketones do not undergo the reaction, probably for steric reasons. The reaction is reversible (by treatment of the addition product with either acid or base ) and is useful for the purification of the starting compounds, since the addition products are soluble in water and many of the impurities are not. ... 

Apart from the reaction of cyclohexanecarboxylic acid with methyllithium, cyclohexyl methyl ketone has been prepared by the reaction of cyclohexylmagnesium halides with acetyl chloride or acetic anhydride and by the reaction of methylmagnesium iodide with cyclohexanecarboxylic acid chloride. Other preparative methods include the aluminum chloride-catalyzed acetylation of cyclohexene in the presence of cyclohexane, the oxidation of cyclohexylmethylcarbinol, " the decarboxylation and rearrangement of the glycidic ester derived from cyclohexanone and M)utyl a-chloroj)ropionate, and the catalytic hydrogenation of 1-acetylcycIohexene. "... 

Attempted direct extension of the two foregoing methodologies to synthesis of the 3-C-methyl analogs of 17, 18, 23 and 24 starting from the diastereoisomeric methyl ketones 10 and 12 was ineffective, as ammonia does not add across the triply substituted double bond of the 3-C-methyl analogs of the esters 19 and 20. However, the phenyl-sulfenimines 25 and 26 add allylmagnesium bromide and diallylzinc with different stereochemistry (8), so that it is possible to have eventual access to the four configurational isomers of 3-amino-2,3,6-trideoxy--3-C-methyl-3-L-hexose. 

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