Ketones, with

Aryl tellurium trichlorides and some tribromides reacted with acetone and methyl phenyl ketone at 20° to yield aryl ketonyl tellurium dihalides. Aryl tellurium triiodides were unreactivef 

4-Methoxyphenyl 2-Oxo-l-propyl Tellurium DichIoride 0.34 g (1 mmol) of 4-mcthoxyphenyl tellurium trichloride is dissolved in 5 ml of acetone in a small flask. The acetone is rapidly evaporated at 20°, another 5 ml of acetone are added to the residue, and the acetone is again evaporated. This procedure is repeated three times. The residue is washed with a small volume of cold methanol and then recrystallized from benzene/petroleum ether (b.p. 50-70°) yield 0.23 g (65%) m.p. 138°. 

Similarly prepared was the following 2-oxo-l-propyl aryl tellurium dichloride  

4-Phenoxyphenyl tellurium trichloride and the aryl tellurium tribromides and triiodides did not react at 20°. Upon heating haloacetones were formedh 

Although not fully understood as yet, a reaction pathway that is consistent with the product formed could proceed by the condensation ketone and diamine with the initial formation of a ketimine 201. This in turn could tautomerize to form enamine 202 KOH may play some role in facilitating this change. Subsequent steps may 

The reaction can be performed by simply maintaining a mixture of the trichloride and excess ketone (1 3) at room temperature, or by refluxing equimolar amounts of the reagents in benzene. Alkyltellurium trichlorides give only low yields of the products. 

Aryltellurium tribromides are generally less reactive towards ketones. MeOC4H4Te(Br2)CH2COPh was prepared by this method.  

Improved reaction times and yields are achieved employing ketone silyl enol ether. 

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By contrast, in the system propionic acid d) - methyl isobutyl ketone (2), (fi and are very much different when y 1, Propionic acid has a strong tendency to dimerize with itself and only a weak tendency to dimerize with ketone also,the ketone has only a weak tendency to dimerize with itself. At acid-rich compositions, therefore, many acid molecules have dimerized but most ketone molecules are monomers. Acid-acid dimerization lowers the fugacity of acid and thus is well below unity. Because of acid-acid dimerization, the true mole fraction of ketone is signi-... 

C HgNjOjS. Colourless needles, with iH20. Prepared by reducing diazotized sulphanilic acid with an excess of sodium sulphite. It is a typical hydrazine in its reactions with ketones, and with acetoacetic ester. The latter reaction gives rise to the tartrazine dyestuffs, and is much used commercially. 

Dimedone derivatives. Dimedone or 6 6-dimethylci/cZohexane-1 3 dioiie j- in saturated aqueous solution J or in 10 per cent. alcohoUc solution gives crystalline derivatives (I) with aldehydes, but not with ketones. The reaction is ... 

An enol is usually characterised by treatment with ketonic reagents or with phenylhydrazme (compare Section IV,114 and Table IV,114A), or by hydrolysis with acid, followed by the identification of the ketone. 

Hydrazories isoelectronic with ketones Comprehensive Organic Synthesis 1991, 2, 503... 

Inspired by the work of Burk and Feaster ) we attempted to use (2-pyridyl)hydrazine (4.36) as a coordinating auxiliary (Scheme 4.10). Hydrazines generally react effidently with ketones and aldehydes. Hence, if satisfactory activation of the dienophile can be achieved through coordination of a Lewis acid to the (2-pyridyl)hydrazone moiety in water. Lewis-add catalysis of a large class of ketone- and aldehyde-activated dienophiles is antidpated Subsequent conversion of the hydrazone group into an amine functionality has been reported previously by Burk and Feaster ... 

Note 2. In the absence of LiBr the coupling was much slower and yields of the carbinols were poor and moderate, respectively. With ketones such as acetone and soluble acetylides the yields were also excellent when no salt was added. 

There also exists an acidregioselective condensation of the aldol type, namely the Mannich reaction (B. Reichert, 1959 H. Hellmann, 1960 see also p. 291f.). The condensation of secondary amines with aldehydes yields Immonium salts, which react with ketones to give 3-amino ketones (=Mannich bases). Ketones with two enolizable CHj-groupings may form 1,5-diamino-3-pentanones, but monosubstitution products can always be obtained in high yield. Unsymmetrical ketones react preferentially at the most highly substituted carbon atom. Sterical hindrance can reverse this regioselectivity. Thermal elimination of amines leads to the a,)3-unsaturated ketone. Another efficient pathway to vinyl ketones starts with the addition of terminal alkynes to immonium salts. On mercury(ll) catalyzed hydration the product is converted to the Mannich base (H. Smith, 1964). 

The widely used Moifatt-Pfltzner oxidation works with in situ formed adducts of dimethyl sulfoxide with dehydrating agents, e.g. DCC, AcjO, SO], P4O10, CCXTl] (K.E, Pfitzner, 1965 A.H. Fenselau, 1966 K.T. Joseph, 1967 J.G. Moffatt, 1971 D. Martin, 1971) or oxalyl dichloride (Swem oxidation M. Nakatsuka, 1990). A classical procedure is the Oppenauer oxidation with ketones and aluminum alkoxide catalysts (C. Djerassi, 1951 H. Lehmann, 1975). All of these reagents also oxidize secondary alcohols to ketones but do not attack C = C double bonds or activated C —H bonds. 

Enamines as nucleophiles react with butadiene, and a-octadienyl ketones or aldehydes are obtained after hydrolysis[57]. This is a good way of introducing an octadienyl group at the o-position of ketones or aldehydes, because butadiene does not react with ketones or aldehydes directly. The reaction of the pyrrolidine enamine of cyclohexanone gives, after hydrolysis, 2-(2,7-octadie-nyOcyclohe.xanone (58) as the main product, accompanied by a small amount of 2,6-di(2,7-octadienyl)cyclohexanone. The reaction of the optically active enamine 59 with butadiene gave 2-(2,7-octadienyl)cyclohexanone (60) in 72% ce[58]. 

In many cases, the a-haloketone does not appear to be an intermediate in this reaction, since reagents such as sulfur trioxide, sulfuric, or 60% nitric add lead to 2-aminothiazole but with lower yields (11 to 43%). Formamidine disulfide [-S-C(=NH)NH2]2, a product of the oxidation of thiourea, seems to be the intermediate in this reaction, since upon treatment with ketones, it gives 2-aminothiazole (604). However, the true mechanism of this reaction has not yet been completely elucidated. 

This reaction also occurs with ketones and may be carried out in a EtOH-EtONa medium. For instance, 5-diethylamino-2-pentanone reacts with 2-benzylthiazole in this way (64). 

Alcohol synthesis via the reaction of Grignard reagents with carbonyl com pounds (Section 14 6) This is one of the most useful reactions in synthetic organ ic chemistry Grignard reagents react with formaldehyde to yield primary alco hols with aldehydes to give secondary alcohols and with ketones to form terti ary alcohols... 

With ketones the e ending of an alkane is replaced by one in the longest con tinuous chain containing the carbonyl group The chain is numbered in the direction that provides the lower number for this group The carbonyl carbon of a cyclic ketone is C 1 and the number does not appear m the name... 

Esters of nonenolizable monocarboxylic acids such as ethyl benzoate give p diketones on reaction with ketone enolates... 

The reaction of the hydrogen sulfite ion in an alkaline solution with ketones and aldehydes is ... 

Furfural reacts with ketones to form strong, crosslinked resins of technical interest in the former Soviet Union the U.S. Air Force has also shown some interest (42,43). The so-called furfurylidene acetone monomer, a mixture of 2-furfurylidene methyl ketone [623-15-4] (1 )> bis-(2-furfurylidene) ketone [886-77-1] (14), mesityl oxide, and other oligomers, is obtained by condensation of furfural and acetone under basic conditions (44,45). Treatment of the "monomer" with an acidic catalyst leads initially to polymer of low molecular weight and ultimately to cross-linked, black, insoluble, heat-resistant resin (46). 

Ai,A/-bis(hydroxymethyl) formamide [6921-98-8] (21), which in solution is in equiUbrium with the monomethylol derivative [13052-19-2] and formaldehyde. With ben2aldehyde in the presence of pyridine, formamide condenses to yield ben2yhdene bisformamide [14328-12-2]. Similar reactions occur with ketones, which, however, requite more drastic reaction conditions. Formamide is a valuable reagent in the synthesis of heterocycHc compounds. Synthetic routes to various types of compounds like imida2oles, oxa2oles, pyrimidines, tria2ines, xanthines, and even complex purine alkaloids, eg, theophylline [58-55-9] theobromine [83-67-0], and caffeine [58-08-2], have been devised (22). 

Reactions. The chemical properties of cyanoacetates ate quite similar to those of the malonates. The carbonyl activity of the ester function is increased by the cyano group s tendency to withdraw electrons. Therefore, amidation with ammonia [7664-41-7] to cyanoacetamide [107-91-5] (55) or with urea to cyanoacetylurea [448-98-2] (56) proceeds very easily. An interesting reaction of cyanoacetic acid is the Knoevenagel condensation with aldehydes followed by decarboxylation which leads to substituted acrylonitriles (57) such as (29), or with ketones followed by decarboxylation with a shift of the double bond to give P,y-unsaturated nitriles (58) such as (30) when cyclohexanone [108-94-1] is used. 

Most nitroparaffins do not react with ketones, but ia the presence of alkoxide catalysts, nitromethane and lower aUphatic ketones give nitro alcohols ia the presence of amine catalysts dinitro compounds are obtained. 

Polymeric -peroxides (3) from hydrogen peroxide and lower carbon ketones have been separated by paper or column chromatography and have been characterized by conversion to the bis(p-(nitro)peroxybenzoates). Oligomeric peroxides (3, R = methyl, R = ethyl, n = 1-4) from methyl ethyl ketone have been separated and interconverted by suitable treatment with ketone and hydrogen peroxide (44). 

Degradation of polyolefins such as polyethylene, polypropylene, polybutylene, and polybutadiene promoted by metals and other oxidants occurs via an oxidation and a photo-oxidative mechanism, the two being difficult to separate in environmental degradation. The general mechanism common to all these reactions is that shown in equation 9. The reactant radical may be produced by any suitable mechanism from the interaction of air or oxygen with polyolefins (42) to form peroxides, which are subsequentiy decomposed by ultraviolet radiation. These reaction intermediates abstract more hydrogen atoms from the polymer backbone, which is ultimately converted into a polymer with ketone functionahties and degraded by the Norrish mechanisms (eq. 

Carbonyl Compounds. Cychc ketals and acetals (dioxolanes) are produced from reaction of propylene oxide with ketones and aldehydes, respectively. Suitable catalysts iaclude stannic chloride, quaternary ammonium salts, glycol sulphites, and molybdenum acetyl acetonate or naphthenate (89—91). Lactones come from Ph4Sbl-cataly2ed reaction with ketenes (92). 

Cyanopyiidine (15) reacts with ketones not beating an a-hydiogen in the presence of sodium metal to afford a tertiary alcohol (a precursor of azacydonol) in high yield, eg, the reaction of (15) and benzophenone yields the tertiary benzyl alcohol [1620-30-0] (23) ... 

Finally, the importance of quinolinium salts to dye chemistry accounts for the long, productive history of their synthesis. The reaction of A/-methylformanihde with ketones, aldehydes, ketone enamines, or enol acetates in phosphoryl chloride leads to high yields of /V-methylquinolinium salts (60). 

When the a,P-unsaturated ketone is hydrogenated to the alcohol, a product with an intense sandalwood odor is produced (162). Many other examples of useful products have been made by condensation of campholenic aldehyde with ketones such as cyclopentanone and cyclohexanone. 

Several kinds of products can be obtained by reaction of thioglycolic acid and its esters with aldehydes to form mercaptals, RCH(SCH2COOH)2, or with ketones to form thiolketals, RR C(SCH2COOH)2. Reaction with formaldehyde (qv) yields di- -butyhnethylene-bisthioglycolate [1433882-0] (MET ester) ... 

The intemiediate (25) reacts with ketones (R 2 0) to form cumulenes RC(CH2)=C=CR2. The indenyl derivative reacts similarly. 

The N,]S -dialkyl-/)-PDAs are manufactured by reductively alkylating -PDA with ketones. Alternatively, these compounds can be prepared from the ketone and -lutroaruline with catalytic hydrogenation. The /V-alkyl-/V-aryl- -PDAs are made by reductively alkylating -nitro-, -nitroso-, or /)-aminodipheny1 amine with ketones. The AijAT-dialkyl- PDAs are made by condensing various anilines with hydroquinone in the presence of an acid catalyst (see Amines-aromatic,phenylenediamines). 

Other substitution reactions have been described with ketones, epoxides, anhydrides, acyl haUdes, amides, and imidates, among others (4). 

Ammonium cyanide [12211-52-8] NH CN, a colorless crystalline soHd, is relatively unstable, and decomposes into ammonia and hydrogen cyanide at 36°C. Ammonium cyanide reacts with ketones (qv) to yield aminonitriles. Reaction of ammonium cyanide with glyoxal produces glycine. Because of its unstable nature, ammonium cyanide is not shipped or sold commercially. Unless it is kept cool and dry, decomposition releases vapors and forms black hydrogen cyanide polymer. 

Fig. 1. Carotenoid pigments -carotene (42), P-apo-8 -carotenal (44), and canthaxanthin (43) = structure (42) with ketone groups at the 4 and 4 positions.

Reactions of 3-chloro-6-methoxypyridazine with ketone enolates in liquid ammonia exhibit characteristics consistent with a radical chain mechanism for substitution (8UOC294). 

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