Ketone, methyl neopentyl

The preparation of neopentyl alcohol from diisobutylene herein described represents an example of acid-catalyzed addition of hydrogen peroxide to a branched olefin, followed by an acid-catalyzed rearrangement of the tertiary hydroperoxide formed. In addition to neopentyl alcohol, there are formed acetone and also small amounts of methanol and methyl neopentyl ketone by an alternative rearrangement of the hydroperoxide. 

Methyl isobutyl ketone was reduced with (- )-menthol-LAH in ether to give the (+ )-(S)-carbinol (53) in low optical yield. Methyl neopentyl ketone was similarly reduced to the (-I- )-carbinol, although pinacolone was reduced to only racemic alcohol. Maximum stereoselectivity in the reduction of both ketones and alkenynols was obtained with a 2 1 (-)-menthol-LAH reagent. The observed low stereoselectivity was attributed mainly to insufficient interaction of the remote isopropyl substituent on the menthyl group with the substituents on... 

Values for 0i and 0,i were determined in the photolysis of two substituted 2-pentanones (Table 24). The quantum yields of acetone and olefin formation were found to be equal and independent of temperature. No wavelength dependence of the primary quantum yield 0n was observed between 3130 and 2654 A in the photolysis of methyl neopentyl ketone. 

When this procedure was applied to the enamine derived from methyl neopentyl ketone, poor yields (< 60 %) were obtained. This was unexpected, since a variety of other ketones had afforded good yields (> 85 %) by the same procedure. The problem was to determine (7) Why the enamine from methyl neopentyl ketone did not work in this procedure, and (2) what to do about it. 

Fig. 14.2 Variation in the conditions affording the maximum yield in the synthesis of morpholine enamines from a series of carbonyl compounds (1) methyl isopropyl ketone, (2) pinacolone, (3) methyl isobutyl ketone, (4) methyl neopentyl ketone, (5) diethyl ketone, (6) diisopropyl ketone, (7) ethyl isobutyl ketone, (8) diisobutyl ketone, (9) isobutyraldehyde,...

Methyl-2-propanethiol 1574 Musk ketone 1556 Neopentyl mercaptan 4276... 

IX-D-13. Photodecomposition of 4,4-Dimethyl-2-Pentanone [Methyl Neopentyl Ketone, CH3C(0)CH2C(CH3)3]... 

Historically, isobutyl alcohol was an unwanted by-product of the propylene Oxo reaction. Indeed, isobutyraldehyde the precursor of isobutyl alcohol was occasionally burned for fuel. However, more recentiy isobutyl alcohol has replaced -butyl alcohol in some appHcations where the branched alcohol appears to have preferred properties and stmcture. However, suppHes of isobutyl alcohol have declined relative to overall C-4 alcohols, especially in Europe, with the conversion of many Oxo plants to rhodium based processes which give higher normal to isobutyraldehyde isomer ratios. Further the supply of isobutyl alcohol at any given time can fluctuate greatly, since it is the lowest valued derivative of isobutyraldehyde, after neopentyl glycol, methyl isoamyl ketone and certain condensation products (10). 

About 69% of the total 1988 U.S. consumption of isobutyraldehyde, went into the production of isobutyl alcohol and isobutyraldehyde condensation and esterification products. The other principal isobutyraldehyde derivative markets (as a percentage of total 1988 U.S. isobutyraldehyde consumption) are neopentyl glycol (15%) isobutyl acetate (6%) isobutyric acid (5%) isobutyUdene diurea (2.5%) and methyl isoamyl ketone (1.7%). 

Materials. Phthalic anhydride (PA), adipic acid (AA), neopentyl glycol (NPG), p-hydroxybenzoic acid (PHBA), salycilic acid, m-hydroxybenzoic acid (MHBA), xylene, and methyl isobutyl ketone (MIBK) were purchased from Aldrich. p-Toluenesulfonic acid (p-TSA) was purchased from Matheson. "Aromatic 150" solvent and "Resimene 7A6", a hexakis(methyloxymethyl)melamine (HMMM) resin were supplied by Exxon and Monsanto, respectively. "Bonderite 1000" pretreated cold-rolled steel panels 3"x9"x2AGA were purchased from Parker. 

The versatility of the APG4 reduction system is further exemplified by the use of P-keto esters as substrates. 3-Oxobutyrates involving methyl, ethyl, t-butyl, or neopentyl esters are reduced to the (S)-hydroxyesters with > 99% ee and in quantitative yield. Moreover, simple aliphatic ketones from 2-octanone to 2-undecanone, as well... 

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