P-Menthanes

DIITIATORS - FREE-RADICAL INITIATORS] (Voll4) p-Menthane hydroperoxide [26762-92-5]... 

A mixture of they -menthadienes can be hydrogenated to produce a mixture of i7j -y-menthane [6069-98-3] and /ra/ j -p-menthane [1678-82-6]. Oxidation to a mixture ofy)-menthane hydroperoxides gives a usehil polymerization initiator used in the mbber industry. 

Highly fluorinated tertiary alcohols usually give olefins on iluormation with sulfur tetrafluoride [759/, but in certain cases, replacement of the hydroxyl group with fluorine occurs under mild conditions Hexafluoro-2-arylpropan-2-ols react with sulfur tetrafluoride at low temperatures to give high yields of heptafluoro-isopropylarenes [766] (equation 77), and similarly, 3,8 dihydroxy 9,9,9,10,10,10-hexafluoro-p-menthane affords 3,8,9,9,9,10,10,10-octafluoromenthane [766] (equation 78)... 

The type substance upon which the nomenclature of the terpeues is based is hexahydro-jj-cymene, which is termed p-menthane, the carbou atoms beiug numbered as shown in the following formula —... 

Scheme 9 Stereoselective synthesis of cw-p-menthane-l,7,8-triol (A) and cA-p-menth-8-ene-l,7-diol (B).

Pig. 32. Acid-catalyzed rearrangement of 1,2 4,8-diepoxy-p-menthane, 6. Values in parentheses are enthalpies relative to 6 in kcal/mol... 

Diepoxy-p-menthane, 6, rearranges when heated with alumina in toluene 73). What is the product of this reaction An organic chemist would predict that acid treatment of the diepoxide 6 (Figs. 3 and 32) would induce one or other of the oxirane rings to open. But which of the two will be the more reactive, and would overall reaction necessarily involve such an initial step Furthermore, for each oxirane there are two possible C—O cleavages. 

Epoxy-p-menthane, 24 528 Epoxy—polyester automotive coatings, 10 447, 449... 

The diastereomeric 2-cli loro-2-nitroso-p-menthanc and 3-chloro-3-nitroso-p-menthane (267) epimerize during photolysis143 (equation 119) and can concurrently give the nitrox-ide 269 as detected by ESR spectrometry, which confirms the mechanism for the photolysis of geminally substituted nitroso compounds (equations 120 and 121). 

A 68% optical yield was obtained with the (- )-boman-2- ido-ol complex, and a 77% optical yield was obtained with a (/ )-(-)-p-menthan-3-ol complex. 

Membrane water electrolyzers, platinum and platinum metal cathodes, 40 122 p-Menthane, 20 281... 

As an example What will be the product of heating l,2 I,4-di-epoxy-p-menthane,J. (Figure 9) with alumina in toluene A chemist would assume initial breaking of an epoxide-ring. But which one of the two Or will both break Furthermore, for each epoxide ring there are two possible choices of C-0 bonds. 

The two diastereomers of cis- and rmws-piperitone oxide are 1,2-epoxy-3-keto-p-menthanes, which have been found in various plant species. The most abundant natural sources of these compounds are plants belonging to the Lamiaceae family, especially Mentha and Calamintha In many publications, the authors gave no details on the diastereomeric composition of piperitone oxides, probably because of their very similar retention times on a non-polar column. 

Kopke X Mosandl A, Stereoisomeric flavor compounds. Part LIV 8-Mercapto-p-menthane-3-one -optically pure stereoisomers and chirospecific analysis, Z Lebensm Unters Forsch 194 372—376, 1992. 

Kopke X Schmarr HG, Mosandl A, Stereoisomeric flavour compounds. Part LVII Xhe stereoisomers of 3-oxo-p-menthane-8-thiol acetate, simultaneously stereoanalyzed with their corresponding thiols, FlavourFragr/7 205—211, 1992. 

Further work on p-menthane hydroxylation using Pseudomonas mendocina-SF (Vol. 6, p. 12) has resulted in isolating the metabolites (160 R=CH20H) and (160 ... 

Cycloheptanes.— The C-1—C-2 bond in -y-thujaplicin is essentially single, Co"-/3-thujaplicin-amine complexes have been described, and thermodynamic data on the U -/3-thujaplicin complex have been calculated. The biomimetic cyclization of the silyl enol ether (191) to karahanaenone (192), using methyl-aluminium bis(trifluoroacetate) is almost quantitative (192) is also synthesized by thermolysis followed by desilylation of the silyl enol ether (193) which is readily available from l-bromo-2-methyl-2-vinylcyclopropane and isobutyraldehyde. Dehalogenation of 3-bromo-l-iodo-3-methylbutan-2-one with Zn-Cu couple on alumina in the presence of isoprene yields (192) and minor amounts of the isomers (194) and (195) however, dehalogenation with Fc2(CO)9 favours (195). Acetolysis of karahanaenol tosylate yields anticipated p-menthane derivatives and no filifolene. ... 

Other papers in this section report catalytic hydrogenolysis of cis- and trans-caranes to m- and p-menthanes, ° the stereochemistry of amines derived from... 

Of the few known terpene compounds that contain heteroatoms such as nitrogen or sulfur, the thiol 8-mercapto-p-menthan-3-one described below has qualitatively important applications as a fragrance and flavor substance. The second thiol, -p-menthene-8-thiol, is described because its odor threshold value is far lower than that of most other fragrance and flavor materials. 

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