Methyl carbinols

Chemical Designations - Synonyms Isobutyl methyl carbinol Methyl Alcohol MAOH 4-Methyl-2-pentanol MIBC MIC Chemical Formula (CH3)2CHCH2CH(OH)CH3. 

Beal and Kagan have shown that reaction of Grignard reagent with 15-ketones (45) gives the 15a-methyl carbinols (46). 

An example is the formation of 47% of the 17/ -methyl carbinol and 38% of the 17a-methyl carbinol in the alkylation of a Iba-acetoxy-n-ketosteroid. ... 

The addition of methylmagnesium bromide to 3j -acetoxy-D-homo-androst-5-en-17a-one (52) proceeds with formation of the equatorial 17a/5-methyl carbinol (53), a result which is analogous to the previously described alkylations of 12-keto steroids. 

The reaction also works with primary and secondary methyl carbinols 8. Those starting materials are first oxidized under the reaction conditions to the corresponding carbonyl compound 1 ... 

There is an isomeric and closely associated alcohol, phenyl-methyl carbinol, CgH5CH OH)CHg, known to chemists. This is a liquid of different odour, but which is not used very much in synthetic perfumery. It is an oil boiling at 203°, and forms an acetate which is found naturally in essential oil of gardenia. This ester is of use in blending perfumes of this type of flower. 

There exist three isomers of phenyl-propyl alcohol, all of which have been prepared and described, and, although not yet introduced into commerce, may eventually be so. These are as follows Benzyl-methyl-carbinol, CgHj. CHj. CH(OH)CHg, boiling at 215° phenyl-ethyl-carbinol, CgHg. CH(OH)CH2. CHg, boiling at 221° and benzyl-dimethyl-carbinol, C Hg. C(OH)(CHg)2, melting at 21° and boiling at 225°. 

The reaction of crotonaldehyde and methyl vinyl ketone with thiophenol in the presence of anhydrous hydrogen chloride effects conjugate addition of thiophenol as well as acetal formation. The resulting j3-phenylthio thioacetals are converted to 1-phenylthio-and 2-phenylthio-1,3-butadiene, respectively, upon reaction with 2 equivalents of copper(I) trifluoromethanesulfonate (Table I). The copper(I)-induced heterolysis of carbon-sulfur bonds has also been used to effect pinacol-type rearrangements of bis(phenyl-thio)methyl carbinols. Thus the addition of bis(phenyl-thio)methyllithium to ketones and aldehydes followed by copper(I)-induced rearrangement results in a one-carbon ring expansion or chain-insertion transformation which gives a-phenylthio ketones. Monothioketals of 1,4-diketones are cyclized to 2,5-disubstituted furans by the action of copper(I) trifluoromethanesulfonate. ... 

The result is not totally surprising, because hydride ion shifts are known in many methylations. Thus, it was proposed that the methyl carbinol is formed by the sequence methylation of a double bond - hydride shift - formation of terminal methylene - epoxidation - opening of the epoxide to aldehyde - reduction to carbinol (Scheme 6). The pathway can explain well the loss of two original hydrogens in methionine methyl group. 

Volume I). The most rapid metabolic deactivating reaction is oxidation to the bioinert C15 oxo prostaglandins. Converting the latter to a tertiary methyl carbinol led to the desired orally active gastric antisecretory agents. 

Oxidation of 2,3-dimethylquinoxaline (from phenylenediamine and diacetyl) with either peracids or hydrogen peroxide in acetic acid gives the 1,4-dioxide (162). Treatment of this bis-N-oxide with selenium dioxide leads to oxidation of one of the methyl groups to the methyl carbinol and formation of... 

Raddeanamine (360) is an unusual spirobenzylisoquinoline alkaloid having a tertiary methyl group in five-membered ring. Methylation of the corresponding ketone gave the methyl carbinol with the reverse stereochemistry, namely, the methyl carbinol 361 was obtained from the reaction of the ketone 294 with methyllithium (Scheme 64). Stereoselective synthesis of ( )-raddeanamine was accomplished by an intramolecular oxyfunctionalization via the 8-methyl-8,14-cycloberbine 364 (175). 

Figure 8. Enzymatic preparation of (S)- and (R)-furyl methyl carbinol. TADH, Thermoanaerobium brokii alcohol dehydrogenase (NADPH was regenerated by glucose/glucose dehydrogenase from Bacillus cereus obtained from Amano.) CCL, lipase from Candida cvlindraceae ChE, cholesterol esterase from Pseudomonas.

The resulting ketone (21-4) is then condensed with methylmagnesium bromide to give the corresponding methyl-carbinol the highly unreactive nature of the carbonyl group at position 11 is further illustrated by the selective reaction at the 6 position. 

METHYL ISOBUTYL CARBINOL Isobutyl methyl carbinol, Methylainyl Alcohol, MAOH, MIBC, MIC Flammable Liquid, III 2 2 0... 

Phenyl methyl carbinol Acetophenone or ethyl- R A. K salt, H20 — 124(W) 138... 

The synthesis of CHDTC02H is, in principle, straightforward and was first accomplished in two laboratories in 1969 150). A modified version of the Comforth synthesis151) is shown in Fig. 67. Most of the steps are self-evident. The doubly labeled phenyl methyl carbinol is, of course, a dl pair in the first instance the absolute stereochemistry at the CHDTX chiral center is RS but the relative stereochemistry of the two chiral centers is defined as IRS,2RS, i.e. only one of the two possible diastereomers is obtained. The resolution at the methyl group occurs automatically when the carbinol is resolved by classical methods. 

Diallyl Methyl Carbinol and Ozone. Explosion has resulted when acetic acid added to this reaction mixture.8... 

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