P-Menthane derivatives

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. ... 

Further papers in this section include a straightforward synthesis of 4-methyl-car-3-ene and some derivatives, another report of cobalt-catalysed air oxidation of car-3-ene cf. Vol. 7, p. 45), anodic oxidation of car-3-ene to yield 2,6,6-trimethylcyclohepta-2,4-dienol predominantly (together with some p-menthane derivatives), a further paper cf. Vol. 8, p. 57) on dehydrogenation of car-3-ene over chromia and chromia-alumina catalysts, the full paper on isomerization of 2,3- and 3,4-epoxycaranes over solid acids and bases, dimerization of (-)-cw-caran-4-one to 4-caranylidenecarane (mostly transoid) using the diamagnetic complex [THF,Cl2Mg2Ti]2, (+)-car-3-ene nitroso-... 

Besides p-menthane derivatives discussed above, there are a few other isoprenoid cyclohexane types with rather limited distribution. Some of these have been found to occur in woody tissues also - e.g., 73, an o-menthane derivative. 

Paftiirana, C., Andersen, R.J., and Wright, J.LC. (1989) Hydralltnanol A, an interesting diphenyl-p-menthane derivative of mixed biogenetic origin from the hydroid HydraUmania falcata. Tetrahedron Lett., 30, 1487-1490. 

Melanoxin, Y5 Melianone, T51 Melittoside, T15 Mellein, 5-methyl, Y2 Mellein, Y2 Mellitoxin, T31 Meloscine, K31 p-menthane derivatives, T4-5 Menthiafolin, T13 Methofuran, Cl Menthol, A26 Menthone, Cl orrho-menthone, T16 Menthylamine, T4 Menthyl chloride, T4 Mephenesin, All Meroquinene, A32 Mesembrene, K20 Metabolite C, T17 ... 

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

Photomutarotation, in addition to inversion of the rotatory dispersion curves, is observed on exposure of ( —)-2-chloro-nitrosocamphane (LXXXIX) to intense light.114,187 On the other hand, isomerization of the normal iso-type without the inversion of the rotatory dispersion curves is involved in the case of 2-chloro-2-nitroso derivatives of pino-camphane (XC), carane (XCI), and p-menthane (XCII).116... 

The resin secreted by Cannabis indica and Cannabis sativa, varieties of hemp, is known variously as marijuana, hashish or bhang and is abused as a hallucinogenic drug. It appears however to have some beneficial properties and is currently under test as an antiemetic in cancer therapy. The secretion contains a number of interrelated oxygen heterocycles, some of which are shown in Scheme 281, which attempts to indicate their biosynthetic relationships (70MI22401). The cannabinoids are probably derived from a monoterpene unit based on p-menthane and 5-n-pentylresorcinol (olivetol), acting the part of a polyketide. 2,2-Dimethylchromene biosynthesis also requires the intervention of an isoprene fragment. 

Recommended Names of Para Derivatives Are Based on Fixed Numbering of p-Menthane Carbon Skeleton... 

The menthane-type radicals given below are based on the p-form of menthane. Names of the radicals derived from the few known o- and m-menthane-type mono-eye lies would be analogous. The established fixed numbering for p-menthane is shown on the formula for p-menthyl the position numbers in all of the recommended radical names are based on this numbering. The names in parentheses shown below some of the recommended names are the common terpene radical names. Examples ... 

Among the hydroformylated l-methyl-4-[alpha-alkoxy-isopropyl]-l-cyclohexenes, i.e. 8-methoxy-p-menthan-2-carboxyaldehyde, the methyl ether 36 (Eq. 15.3.4) smells mangofruit-like and might be used as a perfumery material. The ethyl derivative has a green citrous fragrance, the propyl one has a fresh grass flavour and the butyl one smells woody. 

Essential oil analyses of note this year are of Buchu leaf (some p-menthane sulphur derivatives), Hyssopus officinalis (methyl myrtenate, 2-hydroxyisopinocamphone, pinic acid, and pinonic acid), Laggera aurita (m-menth-6-en-8-ol), some Cymbopogon species (up to 89% of unusual p-menthadienols), and Trichostema lanceolatum (55% p-menthen-4-ol). There... 

Bohlmann has isolated another naturally occurring thymol epoxy-ester (c/. Vol. 1, p. 34 Vol. 3, p. 46), this time from Wedelia forsteriana Compound (137)has been isolated from Pluchea odorata. Pseudomonas fluorescens converts (-)-menthone into cis- and trans-(138). In addition to known (Vol. 2, p. 31) p-menthane-8-thiol-3-ones in Buchu leaf oil, 5-methyl dnd S-acetyl derivatives have been isolated... 

Reactions.—3-Isopropylcyclopent-2-en-l-one reacted with Me-SOl-NaH to give sabina ketone and sabinene oxide 619 the latter could be cleaved to p-menthan-1-ol.620 Thujone and isothujone (for nomenclature see ref. 59) coupled with methyl vinyl ketone under basic conditions to give an adduct that could be modified to sesquithujane (e.g. cubebane) derivatives.621 (—)-Isothujone with HCHO formed the 1-hydroxymethyl derivative that underwent Jones oxidation and decarboxylation to (+)-thujone.622 623... 

As an example of the co-existence of systematic, semi-systematic and trivial names, we could look at the monoterpenoid ketone, carvone. Carvone occurs in both enantiomeric forms in nature, the laevo-form in spearmint and the dextro-form in caraway. The trivial name carvone is derived from the Latin name for caraway, Carum carvi. The basic carbon skeleton is that of l-isopropyl-4-methylcyclohexane. This skeleton is very common in nature and is particularly important in the genus Mentha, which includes various types of mint, since it forms the backbone of most of the important components of mint oils. The skeleton has therefore been given the name p-menthane and the numbering system used for it is shown in Figure 1.3. Therefore, any of the following names may be used to describe the same molecule carvone, p-mentha-1,8-dien-6-one and 1 -methyl-4-(l-methylethenyl)cyclohex-l-ene-6-one. To classify it, we could say it was an unsaturated ketone of the /7-menthane family of monoterpenoids. 

Menaquinone, menadione see vitamin K]. p-Menthadienes. Doubly unsaturated, monocyclic monoterpenes derived from p-menthane. C,oH 6, Mr 136.23, liquids, sensitive to light, air, and heat. Occurrence p-M. are widely distributed in nature. The table (see below) lists those plants from which laiger amounts of p-M. can be isolated from the essential oils. /S-Terpinene and (-)-j8-phellandrene occur in very small amounts only. 

Monocyclic monoterpenic hydrocarbons are derived predominantly from the optically active hydrocarbon 4-isopropyl-1-methylcyclohexane, known as p-menthane (8-2). An exception isp-cymene also known as cymene (l-isopropyl-4-methylbenzene, 8-3), which is an aromatic hydrocarbon. Cymene is a common component of many essential oils, especially the essential oils of cumin (the seed of the herb Cuminum cyminum of the parsley family Apiaceae) and common thyme Thymus vulgaris, from the mint family Lamiaceae) Hsted in Table 8.32 (see later). 

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