Dimethylbutane-2-one

Isothiocyanato-3,3-dimethylbutan-2-one (87) provided the C4N3 fragment that gave, upon reaction with 2-ethylthiosemicarbazide (CN3 fragment) (88), the 3-ethyl-l,6,7,8a-tetrahydro-2,5-dithioxo-8,8,8a-trimethyl-l,2,4-triazolo[l,5-c]pyrimidine 89 (76M1241) (Scheme 33). 

These reaction conditions also permit the chemoselective quantitative reduction of benzaldehyde to benzyl alcohol without any concomitant reduction of either acetophenone or 3,3-dimethylbutan-2-one present in the same reaction mixture.83 Additionally, this useful method permits the reduction of aldehyde functions in polyfunctional compounds without affecting amide, anhydride, eth-ylenic, bromo, chloro, or nitro groups.79,80,319... 

Reaction with ketone and imine functionalities was studied in detail for silylene 85. Reaction of this silylene with ketones such as benzophenone, 3,3-dimethylbutan-2-one, and 2-adamantan-2-one afforded the disilaoxetane compounds 139 in high yields (Scheme 15). The formation of these products most likely occurs via a [2+1] cycloaddition to form a short-lived oxasilacyclopropane intermediate 140, which further reacts with a second silylene to form the final product C19970M4861, 1997PS537>. 

The trifluoromethyl substituent shows peculiar behaviour in S l processes647,649. Reaction of a,a,a-trifIuoro-0-iodotoluene (231) with the enolate of 3,3-dimethylbutan-2-one (232) in liquid ammonia under standard photosensitization conditions yields only a minor amount (8%) of the expected substitution product (233), and mainly (43%) a more complex molecule (234) deriving from it (equation 177). Compound 233 is deprotonated... 

If the ketone is blocked on one side so that it cannot enolize—in other words it has no a protons on that side—only one aldol reaction is possible. Ketones of this type migitt bear a tertiary alkyl or an aryl substituent, f- Butyl methyl ketone (3,3-dimethylbutan-2-one), for example, gives aldol reactions with various bases in 60-70% yield. Enolization cannot occur towards the t- butyl group and must occur towards the methyl group instead. 

In contrast, fluorinated ketones have been used as both nucleophilic and electrophilic reaction constituents. The lithium (Z)-enolate of l-fluoro-3,3-dimethylbutan-2-one can be selectively prepared and undergoes highly diastereoselective aldol condensation with aldehydes to give products 17. ... 

To LiHMDS (lOmraol) and UMPA (lOmmol) in THF (50 mL) at —78 C was added 1 -fluoro-3,3-dimethylbutan-2-one (0.5 g, 4 mmol) in THF over 1 min. To the enolate solution was added rapidly the aldehyde (3 mmol) in THF after stirring for an additional 2 min the reaction was quenched by rapid addition of sat. aq NH Cl. Extractive workup with hexanes gave, after evaporation, a clear oil. By NMR and GC. Isolated yield. 

Thus, treatment of 2-chloroquinoxaline (1) with ketone enolate 2 in liquid ammonia affords l-(quinoxalin-2-yl)-3.3-dimethylbutan-2-one (3), via a thermal Sr 1 mechanism, and 2-/f r(-butylfuro[2,3-Z)]quinoxaline (4), via a competing ionic addition-substitution process. ... 

As a case in point, 3,3-dimethylbutan-2-one (139 Scheme 16) upon reaction with the zirconocene complex of isoprene in benzene at 60 C for 2 h affords (140a), whereas irradiation of the reaction mixture at low temperature in toluene leads to (140b). Mixtures of (140a) and (140b) are obtained by irradiation of isolated (138) and ketone (139) at higher temperatures. As the reaction temperature is lowered, an increasing amount of (140b) is formed. Therefore, it is reasoned that the zirconocene complex reacts in the cis form (138), under thermal conditions, and in the trans form under photochemical eolations. 

U.S. 4867971 (1989) Ryan et al. (Colgate-Palmolive) 0.1-2% 1 -imidazolyl-1 -(4-chlorophenoxy)-3,3-dimethylbutan-2-one (climbazole) pH 4-5.5 A stable homogeneous liquid antidandruff shampoo increased deposition of climbazole enhanced antidandruff efficacy... 

D.18) 2-Butanone, 3,3-dimethyl-, 3,3-dimethylbutan-2-one, tert-butyl methyl ketone, 2,2-dimethylbutanone, trimethylacetone, pinacoline, pinacolone 75-97-8]... 

Treatment of 2 chloroquinoxaline with the potassium enolate of 3,3-dimethylbutan-2-one in liquid ammonia (for 15 minutes, in the dark) gives a mixture of the substitution product (146) (70%) and the furoquinoxaline... 

Butanone, 1-chloro-3,3-dimethyl- tert-Butyl chloro-methyl ketone 1-Chloro-3,3-dimethyl-2-butanone 1-Chloro-3,3-dimethylbutan-2-one Chloromethyl tert-butyl ketone a-Chloropinacolin a-Chloroplnacoline 1-Chloropinacolone Chlorpinakolin EINECS 236-920-6 1-Monochloropinacollne. 

Beiistein Handbook Reference) BRN 1752918 2-Butanone, 1,1-dichloro-3,3-dimethyi- 1,1-Dichlono-3,3-dimelhyl-2-butanone 1,1-Dichloro-3,3-dimethylbutan-2-one Dichloromethyl tert-butyl ketone Dichloropinacolin Dichloropinakolin ra.m-Dichlorpinakolin EINECS 245-111-7. 

At high-temperature conditions, the product distributions of typical decar-boxylative and aldol condensations vary with temperature, time on stream, and catalyst age. Several ketone isomers can be produced. With acetic acid, e.g., C5-C7 (e.g., methylhexanone, pentan-2-one, 3,3 -dimethylbutan-2-one) ketones and alkylphenols arise from acetone aldolization. An important cyclic product in low temperature acetone aldolization is isophorone (2-cyclohexen-l-one, 3,5,5 -trimethyl), formed by the aldol condensation of acetone with mesityl oxide, followed by 1,6-Michael addition. In reactions with acetic acid, we have observed 2-cyclohexen-l-one, 3,5-dimethyl, which is probably a cracking product of isophorone, and small amounts of isophorone itself. Cracking to produce... 

In general the enantioselective hydrogenations of monoketones are less effective than the enantioselective hydrogenation of diketones, but Osawa et al. found special conditions under which methyl-ketones, such as acetone, butan-2-one and 3,3-dimethylbutan-2-one, produced optical yields of 74%, when they were hydrogenated on RNi-TA-NaBr at 100 bar hy ogen pressure and 100°C in a solution of THF, to which pivalic acid has been added. 

Complexes of lithium aluminium hydride with l,4 3,6-dianhydro- and 1,3 4,6-di-O-benzylidene-D-mannitol, each of which contains a two-fold axis of symmetry, have been used to achieve asymmetric reductions of some alkyl aryl and dialkyl ketones e.g. methyl or ethyl phenyl ketone and 3,3-dimethylbutan-2-one). All reductions with lithium l,4 3,6-dianhydro-D-mannitolatodihydridoaluminate(iii), using a 2 1 molecular ratio of ketone to reducing agent, gave the 5-enantiomer of the secondary alcohol preferentially (selectivity 1.1—5.3 %), whereas those of alkyl aryl ketones and dialkyl ketones gave more of the 5- and R-alcohols, respectively, when lithium l,3 4,6-di-0-benzylidene-D-mannitolatodihydridoaluminate(iii) was used. 

The first pinacol rearrangement was conducted by Fittig in 1860, though he did not know the precise constitutions of the starting material and product at the time of the experiment. On treatment of 2,3-dimethylbutane-2,3-diol (pinacol) with sulforic acid, 3,3-dimethylbutane-2-one (pinacolone) was formed. ... 

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