Menthanes

Baccharis genistelloides, from which carquejol is obtained, is not the only Baccharis species to yield an o-menthane. Bohlmann and Zdero have isolated two esters of the type (190) from Baccharis timera  

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 

Inouye, S. Tobita, and M. Moriguchi, Chem. andPharm. Bull. (Japan), 1976, 24, 1406. 

Rivista Ital. Essenze-Profumi, Piante Ojfic., Aromi, Saponi, Cosmet., Aerosol., 1976, 58, 136. 

Sawamura, S. Shima, and H. Sakai, Agric. and Biol. Chem. (Japan), 1976, 40, 649. 

Rogers, J. M. Franco, S. Martinez-Carrera, and S. Garcia-Blanco, Acta Cryst., 1975, B31, 2742. M Y. Senda and S. Imaizumi, Tetrahedron, 1975, 31, 2905. 

Umemoto and T. Nagasawa, Nippon Nogei Kagaku Kaishi, 1977, 51, 245. 

Asakawa, and O. Tanaka, Tetrahedron Letters, 1977, 175. 

356 J Tahara and Y. Sakuda, Kochi Joshi Daigaku Kiyo, Shizen Kagaku Hen, 1976, 24, 1 (Chem. Abs., 

Ensley and R. V. C. Carr, Tetrahedron Letters, 1977, 513 Current Abstracts of Chemistry, Abstract 255 431 incorrectly identifies the product as S-(-)-pulegone. 

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  

Bhatnagar, R. C. Cookson, and R. M.Tuddenham, Tetrahedron Letters, 1974,3903. 2,15 A. Ferro, Rivista Ital. Essenze-Profumi, Piante Offic., Aromi, Saponi, Cosmet., Aerosol., 1974,56,611. 

The conformational equilibria of the four 2-methoxymenthanes and the four 3-methoxymenthanes cf. Vol. 2, p. 27) have been studied using H n.m.r. and correlated214 with optical rotation and rotatory dispersion. H N.m.r. studies have 

208 j Shono, I. Nishiguchi, T. Yokoyama, and M. Nitta, Chem. Letters, 1975,433. 

Gabe and D. F. Grant, Acta Cryst., 1962, 15, 1074 for earlier crystallographic data on this compound, (-)-menthylamine hydrochloride, and (-)-menthylamine hydrobromide, see D. F. Grant and D. Rogers, ibid., 1954, 7, 301. An earlier paper, viz. I. W. Ramsay and D. Rogers, ibid., 1952, 5, 268, records data on a-/-menthol. 

Blount, B. A. Pawson, and G. Saucy, J.C.S. Chem. Comm., 1969, 715 the formula of (4/ ,8R)-p-menth-]-en-9-ol is depicted incorrectly in this paper. 

Cycloheptanes. Thujic acid p-bromophenacyl ester /3-thujaplicin 3,5,7-tri-bromohinokitiol 3,7-dibromohinokitiol 5,7-dibromohinokitiol y-thujaplicin and the di-isopropylditropolonofuran utahin.  

---

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

Commercially, autoxidation is used in the production of a-cumyl hydroperoxide, tert-huty hydroperoxide, -diisopropylbenzene monohydroperoxide, -diisopropylbenzene dihydroperoxide, -menthane hydroperoxide, pinane hydroperoxide, and ethylbenzene hydroperoxide. 

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. 

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). 

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 —... 

Henderson and Sutherland have prepared a hydrocarbon synthetically which is possibly a modification of terpinene. They reduced thymo-hydroquinone, thus obtaining menthane-2-5-diol, which was heated for half an hour with twice its weight of sulphate of potash under a reflux condenser, and so yielded a terpene boiling at 179°, of specific gravity about 0 840 and refractive index 1-4779. 

The German ending -an should be translated -ane if it is the name of a hydrocarbon (or parent heterocyclic compound) which is fully saturated otherwise, -an. Examples methane, menthane, tolan, furan, pentosan. 

Oxo-4-methyl-l-isopropyl-cyclohexan (Menthon) wird an verschiedenen Metall-Ka-thoden in sehr guter Ausbeute zum 4-Methyl-1 -isopropyl-cyclohexan (Menthan) reduziert (in starker Schwefelsaure4 oder in Athanol/Lithiumperchlorat5). 

Since the chemical addition of HCN always results in mixtures of cis/trans-isomers, the stereoselective HNL-catalyzed addition is of great advantage in the synthesis of natural products. The syntheses of the natural monoterpenes cis-p-menth-8-ene-l,7-diol and cA-/ -menthane-l,7,8-triol are interesting examples for the application of this methodology (Scheme 9). ... 

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. 

It should be noted that the preparation of complexes (RNC)AuCN can be carried out via very special routes. Thus AuCN reacts with Mel to give (MeNC)AuCN. This reaction involves an interesting A-alkylation of an Au(i)-bound cyanide group.219 Other (RNG)AuGN complexes were obtained from the reaction of K[AuC14] with the isocyanide in methanol. Examples are the compounds (L)Au2(CN)2 with L = l,8-diisocyano-/>-menthane or 2,5-diisocyano-2,5-dimethyl-hexane. The reactions proceed with a dealkylation of an isocyanide in the coordination sphere of a gold(m) center to produce free cyanide (Scheme 53).201... 

---