Mesityl oxide derivatives

Mesityl oxide (Section 111,79) (I) condenses with ethyl malonate in the presence of sodium ethoxide to give the sodium derivative of (II) this upon hydrolysis with aqueous potassium hydroxide, followed by acidification, gives the cyclic diketone 5 5-dimethyl-l 3-cycfohexanedione (III), of which the enoUc form is 5 5-dimethyldihydroresorcinol (IV) ... 

Various 4-, 5-, or 4,5-disubstituted 2-aryIamino thiazoles (124), R, = QH4R with R = 0-, m-, or p-Me, HO C, Cl, Br, H N, NHAc, NR2, OH, OR, or OjN, were obtained by condensing the corresponding N-arylthiourea with chloroacetone (81, 86, 423), dichloroacetone (510, 618), phenacyichloride or its p-substituted methyl, f-butyl, n-dodecyl or undecyl (653), or 2-chlorocyclohexanone (653) (Method A) or with 2-butanone (423), acetophenone or its p-substituted derivatives (399, 439), ethyl acetate (400), ethyl acetyl propionate (621), a- or 3-unsaturated ketones (691), benzylidene acetone, furfurylidene acetone, and mesityl oxide in the presence of Btj or Ij as condensing agent (Method B) (Table 11-17). 

Some unsaturated ketones derived from acetone can undergo base- or acid-catalyzed exothermic thermal decomposition at temperatures under 200°C. Experiments conducted under adiabatic conditions (2) indicate that mesityl oxide decomposes at 96°C in the presence of 5 wt % of aqueous sodium hydroxide (20%), and that phorone undergoes decomposition at 180°C in the presence of 1000 ppm iron. The decomposition products from these reactions are endothermic hydrolysis and cleavage back to acetone, and exothermic aldol reactions to heavy residues. 

A number of dihydroquinolines have been prepared by treating aniline derivatives with acetone or mesityl oxide in the presence of iodine. In these cases aromatization to the fully unsaturated quinoline would require the loss of methane, a process known as the Riehm quinoline synthesis. Such Skraup/Doebner-von Miller-type reactions are often low yielding due to large amounts of competing polymerization. For example, aniline 37 reacts with mesityl oxide to give dihydroquinolines 39, albeit in low yield. ... 

The well-known condensation between 2-furaldehyde and acetone in a basic medium yields what is usually called furfurylidene acetone monomer composed of a mixture of 2-furfurylidene methyl ketone, di-2-furfurylidene ketone, mesityl oxide and other oligomers derived from further condensation reactions135. This mixture is then polymerized by the action of an acidic catalyst in the first phase of the reaction a polymer of low molecular weight is produced which on further treatment cross-links to a black insoluble and heat-resistant material136. ... 

With the exception of the parent compounds, where the Michael adducts are isolated, acrylic esters [see, e.g. 6,7,31,105,111 ] and nitriles [6,7], and vinyl ketones [26, 113, 115] generally yield the cyclopropanes (Table 7.6) under the standard Makosza conditions with chloroform. Mesityl oxide produces a trichlorocyclopropy-lpropyne in low yield (10%) [7]. When there is no substituent, other than the electron-withdrawing group at the a-position of the alkene, further reaction occurs with the trichloromethyl anion to produce spiro systems (35-48%) (Scheme 7.12) [7, 31]. Under analogous conditions, similar spiro systems are formed with a,p-unsaturated steroidal ketones [39]. Generally, bromoform produces cyclo adducts with all alkenes. Vinyl sulphones are converted into the dichlorocyclopropane derivatives either directly or via the base-catalysed cyclization of intermediate trichloromethyl deriva-... 

In respect of cycloreversion, cyclobutane-fused fullerenes derived from acyclic enones [342] are less stable than their bycycKc equivalents (e.g. 293, Scheme 4.55). For the addition of mesityl oxide the equilibrium constant is so small that a 1000-fold excess of the enone is necessary to complete the reaction. The product of 302 is more stable and requires only a 100-fold excess of the enone. Reaction of 302... 

The most readily available benzo[a]quinolizinium compound is the 2,4-dimethyl derivative, which is easily obtained (75CC489) by a new [4 + 2] reaction between isoquinoline perchlorate and mesityl oxide (204, Scheme 109). The sequence in which the new bonds form remains a matter for conjecture, but the rationalization shown has been presented. 

In addition to conjugated dienes, cyanocobalt catalysts also hydrogenate the C=C bond of activated alkenes.52 Carvene, mesityl oxide, 2-cyclohexenone, benzalacetone and an androstenone derivative were reduced in this way.53... 

In [210, 211] the solid-phase reaction of unsaturated ketones and anilines on a surface of silica gel in the presence of indium chloride under microwave irradiation was described. The library consists of 15 quinolines in yields of 55-87% which were generated quickly and characterized. Ranu et al. [211] showed that dihydro derivatives of qiunolines (e.g., 270 and 273) can also be synthesized, but in this case one component of the reaction must be a 4,4-disubstituted methyl vinyl ketone, for example, mesityl oxide 52 or l-(2-methylcyclopent-l-enyl)ethanone 272 (Scheme 3.75). 

In attempts to carry out the condensation of ketones with nitriles under Ritter reaction conditions, / -acylaminoketones 96-98 were obtained73. Ketones such as acetone, cyclohexanone, mesityl oxide, diacetone alcohol and acetophenone and its substituted derivatives were applied in this reaction (equation 34). 

The mechanism of the Michael addition reaction using ester 3.3 and mesityl oxide is shown in Scheme 3.13. The enolate A derived from the malonic ester (3.3) attacks the (3-carbon... 

Certain N-nitroso derivatives are important intermediates in the synthesis of diazomethane and homologs. One synthesis involves the nitrosation of a /3-alkylaminoisobutyl methyl ketone the corresponding N-nitrosoamine is readily decomposed to the diazoalkane and mesityl oxide by treatment with sodium isopropoxide. ... 

Anthracene hydride (the anion derived from 9,10-dihydroanthracene) reacts rapidly with chalcone to form an anionic Michael adduct along with a chalcone dimerization product (Scheme 83). Prolonged reaction in the presence of anthracene hydride cleaves the Michael adduct into anthracene and the enol-ate of the saturated ketone. The partial structure RCCCO is essential for this fragmentation, as mesityl oxide, for example, gave only the Michael adduct. 

In a similar manner, acetylacetone (340) reacts with dimethylformamide-phosphorylchloride via the heptamethinium derivative (341) by double formylation and leads to 2,4-dichlorobenzaldehyde (342) (84%). 3-Penten-2-one (343a), mesityl-oxide (343 b) and 4-dimethylamino-3-penten-2-one (343 c) undergo triformylation and yield, by subsequent ring-closure, 4-chloroisophthalic dialdehydes (345a-c) ... 

Derivation Condensation of mesityl oxide and dibutyl oxalate in the presence of sodium ethoxide. Grade Technical. 

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