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1. We propose a mechanism for the aldol condensation of acetone in the presence of solid base, explaining the optimum way of forming diacetone alcohol by filling the surface of the base with the diacetone alcohol and acetone anions. 2. Disappearance of the diacetone alcohol from the reaction products after filling the principal centers of the free base was caused by its decomposition under the influence of the acetone anion in the organic phase. 3. The reaction orders for acetone in formation of mesityl oxide and phorone in the presence of solid NaOH are second and third, respectively. 4. We have studied the aldol condensation of acetone in the presence of solid NaOH and benzyltriethylammonium chloride. The formation of diacetone alcohol proceeds in the organic phase as a result of the interaction of the onium alcoholate of diacetone alcohol with acetone, which greatly speeds up the reaction rate. The second order of the reaction with respect to acetone is caused by the limiting step of desorption of the anion of diacetone alcohol inside the organic phase. 5 The role of the benzyldiethylammonium chloride consists of desorption from the surface of the base of the anions of acetone and diacetone alcohol adsorbed on it in the form of ionic pairs, leading to a reduction of the basic properties of the surface of the base.

1. Calculations by the semiempirical MINDO/3 and nonempirical SCF methods predict the formation of an enolate anion, and calculations by the CNDO/BW method the formation of a keto anion, in the deprotonation of acetaldehyde and vinyl alcohol. 2. Formation of an enolate anion was confirmed by comparing the calculated and measured deprotonation energies for the substituted acetaldehydes (acetone, propionic aldehyde, methyl ethyl ketone). 3. MINDO/3 and CNDO/BW calculations on the isomers of mesityl oxide and its anions indicate that the same type of anion will result from detachment of a proton from the γ-CH3 group of the conjugated form of the oxide, from the secondary C atom of the unconjugated form, and from the hydroxyl group of the enol form.

1. Quantum chemical CNDO/BW calculations with optimization of geometries have been carried out on the keto and enol forms of acetone, mesityl oxide, and methyl ethyl ketone, and on the carbanions resulting from various types of deprotonation in these compounds. 2. The keto forms of acetone and mesityl oxide are considerably more stable than the enol forms, while the enolate anions resulting through from heterolytic rupture of the OH bond in the enol forms pass over into the keto form anions with zero activation energy. 3. The calculated gas-phase acidities of the compounds in question here increase in the order: acetone, methyl ethyl ketone, mesityl oxide. 4. Proton detachment from the γ-CH3 group of theβ-form of mesityl oxide, from the secondary C atom of theα-form, or from the hydroxyl group of the enol form leads, in every case, to the same anion structure, namely anα-form carbanion with an unconjugated system of single and double bonds. This, and the anion resulting from proton detachment from theα-methine C atom of theβ-form, are the most stable of the mesityl oxide carbanions. 5. The H atoms bound to the secondary C atom are the most acidic hydrogens in methyl ethyl ketone. Theα-CH3 group acidity is the same in each of the compounds covered by this work.

1. The rate of alkylation of acetone by prehnylchloride (PC) increases linearly with an increase in the OH− ion activity and the PC concentration. The fact that the reaction appears to be zeroth order with respect to acetone is due to the deprotonation of acetone in the aqueous phase, the result being that the acetone concentration in the 50% NaOH solution is that corresponding to saturation, regardless of the original ketone content of the system. 2. The fact that the rate of alkylation changes with a change in the PC-to-acetone ratio and with the introduction of toluene into the system could be the result of changes in the solubility of the catalyst, or the ion pair, in the organic phase. 3. The differences in the effect of NaOH and KOH on the alkylation reaction have been explained, as has the suppression of PC hydrolysis under two-phase catalysis. 4. The usual temperature effects of the aldol condensation carry over to catalysis in two-phase systems.β-Elimination with the formation of mesityl oxide requires the action of a phase-transfer catalyst.

1. The fact that the specific rate of alkylation in two-phase catalytic systems increases in passing from the saturated to the unsaturated ketones, and to phenyl acetone and the cyclic ketones, may be due to an increase in the CH acidity at the alkylation site in the ketone molecule. 2. Kinetic studies have shown that alkylation of mesityl oxide leads to the formation of an unconjugated isopentenyl-α-mesityl oxide which isomerizes to the more stable isopentenylβ-mesityl oxide. 3. The preferential formation of unconjugated products in alkylation of the conjugated form of mesityl oxide is due to the low value of the free energy of deprotonation of the anion of the unconjugated form. 4. Analysis of the thermodynamics of the formation of the neutral forms, and of the carbanions of acetone and mesityl oxide, suggests that carbanion formation does not involve the enol form.

1. By the condensation of α -campholenaldehyde in alkaline with acetone with acetone, 2-butanone, acetophenone, mesityl oxide, and 6-methyl -5 -hepten-2-one, the corresponding unsaturated ketones have been prepared. In spite of the considerable difference from the isomeric ionones in structure, campholenalcetone has an odor close to that of the ionones. The other ketones have pleasant spicelike odors. 2. α-Campholenaldehyde condenses with ethly acetate and with ethyl acetoacetate yielding ethyl campholenalacetate and ethyl 2-campholenalacetoacetate, respectively.

1. 3-Camphenilance carboxaldehyde has been condensed with acetone, with 2-butanone, with acetophenone, with mesityl oxide, and with 6-methyl-5 hepten-2-one, The products formed from acetone and 2-butanone have odors that are reminiscent of that of ionone, and the products obtained from the other ketones have pleasant feeble spicy odors. 2. 3-Camphenilanecarboxaldehyde has been condensed with ethyl acetate end with ethyl acetoacetate, yielding the corresponding unsaturated esters.

1. Vapor phase conversion of mesityl oxide and diacetone alcohol was studied over tricalcium phosphate. 2. It was shown that like H+ and OH− ions, calcium phosphate selectively catalyzes the reaction of vapor phase hydrolytic cleavage of mesityl oxide into acetone. 3. It was found that dealdolization of diacetone alcohol proceeds more completely and under more mild conditions over this catalyst than does the hydrolytic cleavage of mesityl oxide. 4. The results of our work indicate that both in homogeneous catalysis and over a solid catalyst, the hydrolytic cleavage of mesityl oxide proceeds through a hydration step which limits the overall rate of the process.

1. A comparative investigation was made into the properties of a Raney nickel catalyst and an Ni-MgO catalyst prepared from a mixed magnesium-nickel formate in hydrogenation reactions at room temperature. It was shown that vinyl ethers, 1-heptyne, mesityl oxide, styrene, acetals having double and triple bonds, acetophenone, and benzophenone are hydrogenated over Ni-MgO catalyst and Raney nickel at about the same rates. Butanone and benzaldehyde are hydrogenated more rapidly over an Ni-MgO catalyst, but for the hydrogenation of 2-octene, cinnamyl alcohol, cinnamic acid, piperylene, cyclohexene [or cyclohexadiene? see previous note — Publisher], diphenylacetylene, and organosilicon compounds the activity of the Ni-MgO catalyst is lower than that of Raney nickel. 2. It was found that with respect to thermal stability, content of sorbed hydrogen, and possibility of regeneration by oxidation and subsequent reduction this catalyst is similar to Raney nickel. A catalyst obtained by decomposing the mixed salt in an atmosphere of nitrogen is of low activity.

An effective four-stage synthetis of (±)-frontalin from mesityl oxide has been developed with a low-temperature oxy-Cope rearrangement as the key stage.

1. The hydrogenation of the C=C and C=O bonds of mesityl oxide and methyl vinyl ketone proceeds successively. When the hydrogen pressure is increased, the selectivity of the process drops. 2. The rate of addition of hydrogen to the C=C bonds of theα,β-unsaturated ketones studied does not depend upon the degree of shielding of double bonds. 3. 2-Methylpentene-1-one-4 is adsorption-displaced from the surface of the catalyst. The unconjugated double bond of this ketone is hydrogenated four times more slowly than the double bond of mesityl oxide.

1. An investigation was made of the effects of type of catalyst, temperature, and other factors in the reaction of hydrolytic scission of 2-cyclohexylidene cyclohexanone into cyclohexanone. 2. It was shown that, in accordance with the lower degree of conjugation of this ketone, its scission proceeds less readily than that of mesityl oxide. When the reaction was carried out under pressure in presence of an alkaline catalyst. the conversion into cyclohexanone attained 80–90%a A similar result was obtained in a continuous apparatus.

The carbon-carbon multiple bond of mesityl oxide is more reactive toward difluoroamine than the carbonyl group.

On reacting the potassium salt of trinitromethane with acetyl chloride in abs acetone acylation of the trinitromethane anion does not occur and the main product of the reaction is 1,1,1-trinitro-2,2-dimethyl-pentan-4-one formed as a result of the addition of trinitromethane to mesityl oxide which arises from acetone in the process of reaction.

1. Homogeneous catalysts based on complexes of Rh with tyrosine and N-phenylanthranilic acid possess substantially greater activity than the heterogeneous catalyst Rh-C in reactions of hydrogenation of mesityl oxide and methyl vinyl ketone. 2. On a homogeneous rhodium catalyst, just as on a heterogeneous catalyst, the process is selective: only the C=C bond is hydrogenated, while the carbonyl group is not reduced.

1. The reaction of mesityl oxide with anti-benzaldoxime gives the N-alkylation product, namely N-(4-oxo-2-methyl-2-pentyl)-α-phenylnitrone; the reaction is reversible. 2. The treatment of N-(4-oxo-2-methyl-2-pentyl)-α-phenyl-nitrone with hydroxylamine gives N-(4-hydroxyimino-2-methyl-2-pentyl)hydroxylamine and 5-hydroxy-3,3,5-trimethylisoxazolidine. The latter is the intermolecular cyclization product of the intermediate β-hydroxylamine ketone.