Methyl butanol, structure

Figure 9. Structures of additional glycoconjugates isolated from Riesling wine during this study B-D-glucopyranosides of 3-methylbutanol 21, 2-methyl-butanol 22, benzyl alcohol 23, 2-phenylethanol 24, furanoid linalool oxides (two diastereoisomers) 25, pyranoid linalool oxides (two diastereoisomers) 27, 3-oxo-7,8-dihydrc>-a-ionol 28, 3-oxo-a-ionol 29, 4,5-dihydro-vomifoliol 30, vomifoliol 31, and 7,8-dihydro-vomifoliol as well as the 6-O-B-D-apiofurano-syl-fi-D-glucopyranosides of furanoid linalool oxides (two diastereoisomers).

Optical Activity.—We come now, in the case of the isomeric alcohols, to a new and inost interesting example of isomerism. The five carbon alcohol 2-methyl butanol-i, differs from the other seven structurally isomeric amyl alcohols not only in structure, but also in other striking ways. Three different amyl alcohols are known all of which have the constitution of 2-methyl butanol-i. Two of these three are known as optically active all the other amyl alcohols being inactive. Certain substances either in the crystalline form, as in the case of quartz in solution, as in the case of sugar or in the liquid form, as in the case of the alcohol we are considering possess this physical property of optical activity. This property is shown by the fact that the compound has the power to turn or rotate the plane of vibration of a ray of light that has been polarized. 

What we are concerned with at this time is an explanation on chemical grounds of the important fact that three amyl alcohols or pentanolSf are known all of which possess the same structural formula viz., 2-methyl butanol-i and that one of these compounds is dextrorotatory another is levo-rotatory and the third one is inactive. These three are different individual compounds with practically the same physical properties other than optical. The inactive variety of 2-methyl butanol-1 differs, however, from the other seven structurally isomeric pentanols which are likewise inactiye not only in its structure but also in the fact that by means of certain reactions there may be obtained from it both the dextro-rotatory and the levo-rotatory compounds. In it, and in other inactive compounds of the same kind, there are present equivalent amounts of the two oppositely active compounds,... 

Though we can thus explain the existence of these three alcohols which possess the structural formula of 2-methyl butanol-1 we do it in each case only in terms of the other two, i.e.y the inactive compound consists of a mixture of the dextro and levo forms and conversely. How then can we account for the fact that the two active isomers and, therefore, the three together are possible with the same structural formula ... 

Theory of van t Hoff-LeBel.—Two men independently of each other advanced a theory which explains these facts. One, a Dutch chemist by the name of van t Hoff, and the other a French chemist, LeBel. On examining the structural formulas of optically active compounds these men each saw that they differed in a common way from all optically inactive compounds which were not possible of being split into optical components. Taking as an illustration the alcohol with which we are dealing, viz., active amyl alcohol or 2-methyl butanol-1 we see by examining its formula that one of the carbon atoms is characteristically different from all of the others. 

Structures of 2 -Methyl -Butanol and sec-Butyl Chloride Depicted in the Convention that Identifies the Chiral Center and the Direction of the Bonds to the Chiral Carbon... 

Treatment of 3 methyl 2 butanol with hydrogen chloride yielded only a trace of 2 chloro 3 methylbutane An isomeric chloride was isolated in 97% yield Suggest a reasonable structure for this product... 

The beneficial effect of the change of the flow rate of the mobile phase has also been exploited for the improvement of CCC purification of the components of the dye Quinoline yellow (Colour Index No. 47005). The chemical structures of the components of Quinoline yellow are shown in Fig. 3.121. The two-phase system used for the purification consisted of tm-butyl methyl ether-l-butanol-ACN-0.1 M TFA (1 3 1 5 v/v). The column... 

A comparison of the kinetics of alkaline hydrolysis of methyl, isopropyl and butyl acetates in propan-2-ol-water and t-butanol-water has revealed that the observed effects correlate with solvent structure. ... 

In order to explain the structures of the decenes by the action of 75% sulfuric acid on 3-methyl-2-butanol (methylisopropylcarbinol), it is necessary to assume the intermediate formation of 2-methyl-2-butene and 2-methyl-l-butene in the ratio of 3 to 1 ... 

Change-transfer complexes of solute-alcohol stoichiometry 1 2 have been reported by Walker, Bednar, and Lumry3 for indole and certain methyl derivatives (M) in mixtures of associating solvents n-butanol and methanol (Q) with n-pentane these authors introduced the term exciplex to describe the emitter of the red-shifted structureless fluorescence band which increases in intensity with the alcohol content of the mixed solvent. The shift of the exciplex band to longer wavelengths as the solvent polarity is increased, described by Eq. (15), confirms the dipolar nature of the complex that must have the structure M+Q2. No emission corresponding to the 1 1 complex is observed in these systems which indicates (but does not prove) that the photo-association involves the alcohol dimer. The complex stoichiometry M+Q determined from (Eqs. 9, 10, and 12)... 

It was found in transesterification of ethyl acrylate in the liquid phase over a non-porous KU-2 catalyst [464], that the structure of the alcohol influenced the value of the limiting sorption of alcohol by the ion exchanger, the logarithm of this value being a linear function of the dielectric constant of the alcohol. As the second-order rate coefficients yielded the same sequence as the limiting sorption values, viz. allyl alcohol > 1-butanol > 3-methyl-l-butanol, Filippov et al. [464] assumed a relation between the dielectric constant and the reactivity of the alcohols. 

Except for the biochemical example just cited, the structures of all of the alcohols in Section 5.9 (including those in Problem 5.13) were such that each one could give only a single alkene by (3 elimination. What about elimination in alcohols such as 2-methyl-2-butanol, in which dehydration can occur in two different directions to give alkenes that are constitutional isomers Here, a double bond can be generated between C-l and C-2 or between C-2 and C-3. Both processes occur but not nearly to the same extent. Under the usual reaction conditions 2-methyl-2-butene is the major product, and 2-methyl-1-butene the minor one. 

AMYL ALCOHOLS. Amyl alcohol describes any saturated aliphatic alcohol containing five carbon atoms. This class consists of three pentanols, four substituted butanols, and a disubshtuted propanol. i.e.. eight structural isomers CvHdO four primary, three secondary, and one tertiary alcohol. In addition, 2-pentanol, 2-methyl-l-butanol. and 3-methyl-2-butanol have chiral centers and hence two enantiomeric forms,... 

In this type of problem, one should work backward from the structures of the final products, analyzing each reaction for the structural information it gives. The key questions to be inferred in the preceding problem are (a) What kind of chiral compound or compounds could give 2-methyl-2-butanol and a chiral alcohol with nitrous acid (b) What kinds of compounds could give 8 on reduction (c) What does the solubility behavior of A indicate about the type of compound that it is (d) Why does chiral A racemize when dissolved in alkali ... 

The enol acetate 77 of 3,4-dihydro-7-methoxy-5-methyl-l-(2l/)-naphthalenone was converted to the acid 78 by ozonolysis and hydrolysis and this by a Wittig reaction with a-methoxyethyltriphenyl-phosphonium chloride gave 79. Compound 79 was converted into 80 by a series of reactions, five in number, which in turn was converted into 81 by reaction with potassium in -butanol. The methyl ester of compound 81, one isomer of which was recognized as that having the correct stereo structure, was converted to 82 by heating with acetic anhydride and 10-camphorsulfonic acid. Subsequent steps involved ozonization, reaction with V,iV -carbonyldiimidazole, lactam formation, reaction with pyridinium bromide perbromide, reaction with sodium hydride, and a further series in which (+ )-oxodendrobine (83) was ultimately obtained. Reduction of the latter to ( )-dendrobine... 

We turned our efforts to a synthesis in which a chiral 5-carbon unit would be coupled to a 6-carbon structure bearing functionality permitting resolution. The 5-carbon fragment would contain the hydrocarbon asymmetric center (C-8 of VII) the other unit would provide C-2. Commercially available (S>)-2-methyl 1-butanol was determined to be >99% pure. However, the R-alcohol (acid, aldehyde, etc.) would have to be synthesized. Asymmetric alkylations of chiral a-metallated amides were performed, but the enantiomeric excesses were not sufficiently high. In particular we noted that alkylations involving a short chain bifunctional compound (e.g., 3-methoxy-propyl iodide) provided slightly lower ee s than did the parent alkyl iodide. 

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