Menthane derivatives 328

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. ... 

The acetylation of cis-cyclononene with acetyl chloride and aluminium chloride leads to a mixture, whose main component is a menthane derivative, chloro-l-acetyl-4-isopropylcyclohexane. ... 

A mixture of o-menthanes resulted from reduction of o-cymene with Ca(NH3)6,297 and a neat route to the o-menthane skeleton involved photochemical addition of allene to 3-methylcyclohex-2-en-l-one and opening of the cyclobutyl ring with BF3.298 O-Menthadi- and tri-enes resulted from pyrolysis of verbenene.299 Acid-and base-promoted isomerizations of o-menthadienes300 and dehydration of cis- and trans- o-menthan-8-ols with a variety of reagents have been recorded.301 Optically active 2-methyl-4-isopropenylcyclohexanone (which is a useful precursor for ra-menthane derivatives) has been prepared by pyrolysis of chiral 2,2,5-trimethyl-bicyclo[3.1.1 ]heptan-2-one.302... 

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 ... 

CitroneUal can also be converted to the ds- [92471-23-3] (88) and / 3 -/)-menthane-3,8-diol [91739-72-9] (89) by reaction with dilute acids (176,177). The glycol mixture can be readily purified by distillation and the two isomers easily separated. The glycols are usehil as insect repellents (qv) and are especially effective against mosquitos (178). Derivatives of the glycols have been prepared and are usehil as insecticides and plant growth regulators (179). 

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

Chemical Properties. Hydrogenation of menthols yields / -menthane oxidation with chromic acid or catalytic dehydrogenation yields menthones. Dehydration under mild conditions yields 3-/ -menthene as the main product. Reaction with carboxylic acids or their derivatives yields menthyl esters, which are used mainly as aroma substances and in pharmaceutical preparations and formulations. The esterification of menthols with benzoic acid is used on an industrial scale in the resolution of racemic menthol. 

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. 

Using the CH multiplicities as obtained from two DEPT experiments (Fig. 2.59(d, e)), the CH skeleton can be derived in the next step, so that the compound turns out to be a 1,2,4-trisubstituted cyclohexane of the menthane type ... 

Type A. Those which contain as ring substituents an iso three-carbon group and a one-carbon group, usually in para position for a few hydrocarbons of this type, these groups are in meta or ortho position. Thus, Type A monocyclics may be considered as derivatives of menthane (isopropylmethylcyclohexane) or of cymene (isopropylmethylbenzene). 

For the Type A monocyclic terpene hydrocarbons (para, ortho, and meta derivatives of menthane) use the menthane, menthene, and menthadiene names and the well-established fixed numbering of menthane. 

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

Several teachers expressed the opinion that they would like to see the numbering assigned to menthane (whether it is the historical numbering or a new numbering) retained for bicyclics and other terpene derivatives to simplify the following through a series of terpene transformation reactions. 

For the parent compound of the menthane-type (Type A) monocyclic terpene hydrocarbons, the name menthane, its well-established fixed numbering of the carbon skeleton, and extension of nomenclature rules to apply to double bonds outside the ring have been recommended (for the p-form, see Formula 6, Chart 5, p. 19). These recommendations and the extension of nomenclature practices to apply to points of attachment outside the ring are basic to the rules for forming the names of menthane-type monocyclic radicals. Since the enumeration of the parent compound is fixed, the position number of a point of attachment in radicals derived from it is predetermined and will not always be numbered as 1. 

Rule 1 Form the names of univalent radicals derived from menthane (the saturated parent hydrocarbon of menthane-type monocyclic terpenes) by replacing the ane ending of the hydrocarbon name with "y/ . That is menthyl. 

Rule 2 Form the names of univalent radicals derived from the unsaturated menthane-type monocyclic terpene hydrocarbons containing one double bond, which may be either in the ring or outside the ring, by replacing the final e" of the hydrocarbon name (menthene) with "yV That is menthenyl. 

Rule 4 Form the names of bivalent radicals derived from menthane and having two points of attachment on the same carbon atom by adding "idene99 to the names of the saturated univalent radicals. That is menthylidene. 

Rule 5 Form the above types of names for all hydrocarbon terpene radicals derived from menthane-type monocyclic hydrocarbons regardless of the position of the point or points of attachment that is, the H or H s may be removed from carbons in the ring or from carbons in the numbered side chains. Use position numbers to designate the position of the point or points of attachment in the radicals. 

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 ... 

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