Ketones, unsaturated reaction with

The presence of unsaturation in the side chain is also compatible with antihistaminic activity. Mannich condensation of p-chloroacetophenone with formaldehyde and pyrollidine affords the amino ketone, 109. Reaction with an organometallic reagent from 2-bromopyridine gives 110. Dehydration leads to triproli-dine (111). ... 

Peroxy adds may epoxidize unsaturated ketones [299, 332], but a concomitant Baeyer-Villiger reaction is possible [254] (equations 389 and 391). Other ways of forming epoxy ketones are reactions with salts of hypochloric acid [691, 704] and with V-bromosuccinimide [746]. Mesityl oxide is converted into its epoxide, as shown in equation 437 [142, 220, 254, 746]. 

On the one hand, thioacetals of a,B-unsaturated ketones resulting from the a-alkylation reaction reported above have been transformed efficiently into the corresponding unsaturated ketones on reaction with mercury(II) chloride and oxide in methanol (Scheme 71, entry or on reaction - with... 

Reaction with amides. Benzamides and thiobenzamides are converted to a,a-disubstituted benzylamines. Tertiary amides form ketones on reaction with RCeCl even when the reagent is present in large excess, therefore Weinreb amides are not necessary for the ketone synthesis. Enaminones are also attacked at the carbonyl group, and in the cases of a -silylated derivatives the reaction products are 3,y-unsaturated ketones. ... 

When the substrates are i -halo-a,)8-unsaturated ketones the reactions with cyclopropyl-cuprates lead to the corresponding )9-cyclopropyl enones, In each case, when a comparison was made, the jS-iodo enone gave the produet in better yield under milder conditions than when the yS-bromo enone was used." It is also noteworthy that products resulting from addition of a cyclopropyl moiety to the initially formed -cyclopropyl enone were not detected. In accordance with this, successive treatment of bromocyclopropane with tert-butyllithium, phenylsulfanylcopper, and 3-iodocyclopent-2-enone gave 3-cyclopropylcy-clopent-2-enone (2a) in 97% yield.Under the same conditions a 1 1 mixture of endo-and cxo-6-bromobicyclo[3.1. Ojhexane was coupled to 3-iodocyclohex-2-enone leading to a 1 1 mixture of endo- and e.xo-3-(bicyclo[3.1.0]hex-6-yl)cyclohex-2-enone (3) in 94% total yield further examples have been reported. ... 

Other synthons for 1,3-dicarbonyl compounds that have been successfully applied include p-chloro-a,P-unsaturated ketones and aldehydes, P-dimethylamino-a,P-unsaturated ketones (easily obtained from ketones by reaction with DMFDMA), P-alkoxy-enones"" and vinyl-amidinium salts."" Alkynyl-ketones react with 5-alkyl-isothioureas, giving 2-alkylthio-pyrimidines" and propiolic acid reacts with urea to give uracil directly in about 50% yield. "" 1,3-Keto-esters with formamidine produce 4-pyrimidinones"" and C-substituted formamidines with ethyl cyanoacetate give 2-substituted-6-amino -pyrimidinones. In analogy, pyrimidines fused to other rings, for example as in quinazolines, can be made from ortho-aminonitriles " and in general, from P-enamino esters. ... 

However, as Weitz and Scheffer found,43 <%,/ -unsaturated ketones give epoxy ketones in reaction with hydrogen peroxide in alkaline solution. 

Cyclopropane 1,4-dicarbonyl systems are produced from a, -unsaturated aldehydes and ketones by reaction with diazoketones in the presence of antimony pentafluoride, generally in high yield [equation (19)], and y-keto-aldehydes... 

Allyl bromides may be converted to j8,y-unsaturated ketones by reaction with nitrile oxides followed by reduction and hydrolysis of the resulting oxime (Scheme... 

The most important reactions taking place on the hydroxy groups of alcohols are 0-H bond cleavage and C-O bond cleavage. With the O-H bond cleavage, reactions with strong acids proceed, as do oxidations of primary alcohols to aldehydes, secondary alcohols to ketones and reactions with organic acids (formation of esters). In foods the last three reactions are particularly important, and are usually enzymatically catalysed. Other important reactions are dehydration and the opposite reaction, hydration, which yield unsaturated hydrocarbons from alcohols and isomeric alcohols from unsaturated hydrocarbons, respectively. These reactions are particularly important in terpenic alcohols. In oleochemistry, oxidation and esterification reactions are used for the production of various lipid derivatives. 

Barbee TR, Guy H, Heeg MJ, Albizati KF. Functional group hybrids. Reactivity of a -nucleofuge a,(3-unsaturated ketones. 2. Reactions with malonate anion. Concerning the mechanism of the Favorskii rearrangement. J. Org. Chem. 1991 56 6773-6781. 

Cycloaddition of COj with the dimethyl-substituted methylenecyclopropane 75 proceeds smoothly above 100 °C under pressure, yielding the five-membered ring lactone 76. The regiocheraistry of this reaction is different from that of above-mentioned diphenyl-substituted methylenecyclopropanes 66 and 67[61], This allylic lactone 76 is another source of trimethylenemethane when it is treated with Pd(0) catalyst coordinated by dppe in refluxing toluene to generate 77, and its reaction with aldehydes or ketones affords the 3-methylenetetrahy-drofuran derivative 78 as expected for this intermediate. Also, the lactone 76 reacts with a, /3-unsaturated carbonyl compounds. The reaction of coumarin (79) with 76 to give the chroman-2-one derivative 80 is an example[62]. 

Polymeric OC-Oxygen-Substituted Peroxides. Polymeric peroxides (3) are formed from the following reactions ketone and aldehydes with hydrogen peroxide, ozonization of unsaturated compounds, and dehydration of a-hydroxyalkyl hydroperoxides consequendy, a variety of polymeric peroxides of this type exist. Polymeric peroxides are generally viscous Hquids or amorphous soHds, are difficult to characterize, and are prone to explosive decomp o sition. 

Reaction with Organic Compounds. Aluminum is not attacked by saturated or unsaturated, aUphatic or aromatic hydrocarbons. Halogenated derivatives of hydrocarbons do not generally react with aluminum except in the presence of water, which leads to the forma tion of halogen acids. The chemical stabiUty of aluminum in the presence of alcohols is very good and stabiUty is excellent in the presence of aldehydes, ketones, and quinones. 

Olefins may be obtained by elimination from the organoboron intermediates formed from enol derivatives and diborane. " As in the reaction with a,jS-unsaturated ketones (section IX), the conversion is carried out in two parts first formation of the diborane adduct and second, decomposition in refluxing acetic anhydride. 

The opening of epoxides with neighboring keto groups, accompanied by vinylogous jS-elimination, has already been mentioned (section V). This is an extension of the jS-elimination reactions which occur when a,p- or jS,y-epoxy ketones are opened with acid or base. a,jS-Epoxy ketones give a-substituted a,jS-unsaturated ketones [(162), for example], and j5,y-epoxy ketones give y-substituted a,jS-unsaturated ketones [(163), for example] ... 

The reaction with the jff,y-unsaturated A °k3 ketone (20) in pyridine proceeds in 25% yield to the 10j -fluoro ketone (21). a,yS-Unsaturated ketones do not react with perchloryl fluoride. 

Isolated double bonds do not interfere with this reaction sequence, but other ketones (saturated or a, -unsaturated) will also form enol acetates, which in turn are capable of further reaction with 7V-iodosuccinimide. 

A valuable extension of the diazomethane reaction for the preparation of A-homosteroids was discovered by Johnson, Neeman and Birkeland " who found that a,j5-unsaturated ketones are homologated by reaction with diazomethane in the presence of either fluoroboric acid or boron trifluoride. The main product is formed by the insertion of a methylene group between the carbonyl group and the unsaturated a-carbon to give a / ,y-unsaturated ketone. 

Steroidal a,j8-unsaturated ketones such as /l -3-ketones undergo a facile reaction with pyrrolidine to give the corresponding, d - -dienamines (111) (40,53). The reaction is much slower with morpholine and piperidine, which is undoubtedly due to the generation of the double bond exocyclic to the six-membered hetero rings in the step involving the dehydration of the intermediate carbinolamine (112) to the corresponding iminium ion (113). 

The reaction of enamines with perfluoro olefins has also been reported (62). Dienamines have been reported to react with ethyl acrylate at C2 to give the alkylated a,j8-unsaturated ketone derivative. Thus the dienamine (44) gave 71 in 50 % yield on reaction with ethyl acrylate in dioxane for 40 hr (63). 

A reaction related to the Michael addition reactions of enamines to unsaturated esters, which leads to S-ketoesters, is the reaction with 1-carb-ethoxy-l-cyanocyclopropane (318). This gives access to ketones substituted with the next higher homologous acid chain. 

The Fiesselmann reaction has been extensively used with p-halovinyl esters, ketones,aldehydes and nitriles as reaction partners for thioglycolic acid and its derivatives. This reaction with P-halovinyl aldehydes has been extensively explored as a result of the availability of P-chloro-a,P-unsaturated aldehydes via the Vilsmeier... 

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