Methyl ketones carboxylic acids

As further illustrated in Scheme 2, the 1-methyl- and 1,3,3-trimethylcyclopropene are rapidly metallated with organolithium reagents in ether to afford stable solutions of the 1-lithiocyclopropenes (18) In comparison, solutions of the metallocyclopropenes (16) are significantly less stable and even at — 40°C are observed to degrade slowly to a mixture of dimeric and trimeric products apparently formed by nucleophilic addition of 16 to the highly reactive cyclopropene n system L Alkylation of 18 (R=H or Me) with methyl iodide produced 1,2-dimethyl- and 1,2,3,3-tetramethylcyclopropene . The trimethyl derivative 18 (R = Me) has also been carbonated and acylated to afford the corresponding 2,3,3-trimethylcyclopropene carboxylic acid, methyl ketone and carboxaldehyde. 

Carbon tetrachloride, CCI4, in the presence of potassium hydroxide at 25-80 °C, transforms primary alcohols into carboxylic acids, methyl ketones into acids with the same number of carbons or with one less carbon in the chain, and aryl methyl sulfones into arenesulfonic acids [954]. 

In recycled PP, 61 compounds were detected and 35 of them were identified. Many peaks showed very low separation levels making their identification difficult. In virgin and recycled PP the following compounds were identified Ethylbenzene and xylene were found only in the recycled resin. Present in both virgin and recycled PP were a large number of branched alkanes and n-alkanes between Qg and C25. Octadecanoic acid, methyl ester and dibutyl palmitate, which is a typical compound used in the cosmetic industry, were found only in the recycled PP. Amines such as hexamine, 3-ethyl and NIN"N" trimethyl dipropylene triamine were identified in both PP materials. Carboxylic acids and ketones were absent in both polymeric materials and so were fragrance or flavour compounds [113]. 

During the total synthesis of (+)-anthoplalone by K. Fukumoto et al. one of the intermediates was a cyclopropyl methyl ketone, and the synthetic sequence required the conversion of this functionality to the corresponding cyclopropane carboxylic acid methyl ester. This transformation was accomplished via the haloform reaction using bleach in methanol. The methyl ester and some carboxylic acid was obtained after this step, so the product mixture was treated with diazomethane to convert the acid side product to the methyl ester. 

The decarboxylation of carboxylic acid to ketone is known to be promoted by basic oxides such as CaO and 81203. The dimerization of HCHO to methyl formate by Tischenko reaction is known to be promoted by acid-base bifunctional action of catalyst. The decomposition of formic acid to CO2 is known to be promoted by basic sites. ... 

Thionyl chloride is one of the most common and effective reagents to effect cyclodehydration of 2-acylamino ketones. For example, Litak and Kauffman refluxed 446 in SOCI2 and isolated 4-[2-(3,4-dihydro-2//-l-benzopyran-6-yl)oxazol-5-ylpyridine 447 in excellent yield (Scheme 1.123). Both 447 and 441 were starting materials for reactive fluorescent stains to be used in fluorescence microscopy. Reck and Friedrichsen refluxed 448 in SOCl2/chloroform and prepared 4-(methoxy-carbonyl)-2-methyl-5-oxazoleacetic acid methyl ester 449 (Scheme 1.123). This material was a precursor of the novel diene 4-methoxy-2-methyl-furo[3,4-ti]ox-azole-6-carboxylic acid methyl ester 450. 

Derivatization Ketones oximes Hydroxyl groups trimethlylsilyl or f-butyidimethylsilyl ethers Carboxylic acids methyl esters... 

Feng Q, Huang K, Liu S, Yu J, Liu F (2011) Electrocatalytic carboxylation of aromatic ketones with carbon dioxide in ionic liquid l-butyl-3-methylimidazoliumtetrafluoborate to alpha-hydroxy-carboxylic acid methyl ester. Electrochim Acta 56(14) 5137-5141. doi 10.1016/j. electacta.2011.03.061... 

Reactions of trimethylsilylmethyllithium with secondary and tertiary carboxylic acid methyl or ethyl esters give the corresponding a-trimethylsilyl ketones 45 in... 

Chloro-3-ethylbenzoxazolium salts (565) are remarkably versatile reagents the fluoroborate converts a-hydroxy-carboxylic acids into ketones, e.g. benzilic acid into benzophenone, methyl thiocarbamates RNHCSOMe into isocyanates RNCO, ° and alkyl- and aryl-formamides into isocyanides the chloride transforms alcohols into alkyl chlorides. 

Belov et al. (2011) evaluated the potential of N,N-dimethylformamide dimeth-ylacetal (DMF-DMA) as a methylating agent for a variety of p-substituted phenols under microwave irradiation. The reaction was completed within 30 min if substituent is an electron-withdrawing group while it is over in 60 min, if substituent is an electron-donating group. Enamino-ketone formation and esterification were obtained with carboxylic acid and ketone functional group, respectively. 

These are effective high-octane gasoline additive oxygenates. The conversion of isobutane into isopropyl, methyl ketone, or isopentane into isobutyl, methyl ketone is illustrative. In this reaction, no branched carboxylic acids (Koch products) are formed. 

A more eflicient and general synthetic procedure is the Masamune reaction of aldehydes with boron enolates of chiral a-silyloxy ketones. A double asymmetric induction generates two new chiral centres with enantioselectivities > 99%. It is again explained by a chair-like six-centre transition state. The repulsive interactions of the bulky cyclohexyl group with the vinylic hydrogen and the boron ligands dictate the approach of the enolate to the aldehyde (S. Masamune, 1981 A). The fi-hydroxy-x-methyl ketones obtained are pure threo products (threo = threose- or threonine-like Fischer formula also termed syn" = planar zig-zag chain with substituents on one side), and the reaction has successfully been applied to macrolide syntheses (S. Masamune, 1981 B). Optically pure threo (= syn") 8-hydroxy-a-methyl carboxylic acids are obtained by desilylation and periodate oxidation (S. Masamune, 1981 A). Chiral 0-((S)-trans-2,5-dimethyl-l-borolanyl) ketene thioketals giving pure erythro (= anti ) diastereomers have also been developed by S. Masamune (1986). 

In his cephalosporin synthesis methyl levulinate was condensed with cysteine in acidic medium to give a bicyclic thiazolidine. One may rationalize the regioselective formation of this bicycle with the assumption that in the acidic reaction mixture the tMoI group is the only nucleophile present, which can add to the ketone. Intramolecular amide formation from the methyl ester and acid-catalyzed dehydration would then lead to the thiazolidine and y-lactam rings. The stereochemistry at the carboxylic acid a-... 

The haloform reaction is sometimes used for the preparation of carboxylic acids from methyl ketones... 

The methyl ketone shown in the example can enohze in only one direction and typifies the kind of reactant that can be converted to a carboxylic acid in synthetically accept able yield by the haloform reaction When C 3 of a methyl ketone bears enolizable hydro O... 

Primary synthesis has limited application in making pyrimidine-carboxylic acids or even their esters. However, some pyrimidine-4(and 5)-carboxylic acids can be effectively so made. For example, bromomucic acid (785) reacts as an aidehydo ketone with S-methyl-thiourea to give 5-bromo-2-methylthiopyrimidine-4-carboxylic acid (786) directly (53JCS3129) while the Whitehead synthesis (Section 2.13.3.1.2<7) can give, for instance, 3-methylcytosine-5-carboxylic acid (787) (55MI21300). 

In addition to the applications indicated on p. 858. hypohalous acids are useful halogenating agents for Ixjth aromatic and aliphatic compounds. HOBr and HOI are usually generated in silii. The ease of aromatic halogenation increa.ses in the sequence OCl < OBr < Ol and is facilitated by salts of Pb or Ag. Another well-known reaction of hypohalites is their cleavage of methyl ketones to form carboxylates and haloform ... 

Buu-Hoi has shown that n-alkyl methyl ketones excluding ethyl methyl ketone, yield primarily 2-monosubstituted cinchoninic acids. It has been demonstrated that the products of the condensation of isatin with aryloxyketones are the corresponding 3-aryloxy-4-quinoline carboxylic acids rather than the isomeric 2-aryloxymethylcinchoninic acids.In the case of simple a-alkoxyketones such as 1-alkoxyethyl methylketones, the preferred products are the 2-alkoxyalkylcinchoninic... 

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