A-Caryophyllene

Deussen termed the inactive caryophyllene, as further experiments showed it to be, a-caryophyllene, and the laevo-rotatory compound, )8-caryophyllene. A third body was obtained, which yielded no blue nitrosite at all, to which Deussen assigned the name -y-caryophyllene. This body... 

Semmler and Mayer agree that the reagent used and the conditions of temperature, etc., govern the character of the sesquiterpene, or mixture of sesquiterpenes which result. By using sodium methylate very cautiously, they obtained a caryophyllene having the following characters —... 

By using pyridine to split off the hydrochloric acid, Semmler and Mayer obtained a caryophyllene substantially identical with that obtained by Schimmel, but of optical rotation - 57°, indicating that Schimmel s body was a mixture of the two compounds. Semmler and Mayer give the following formulae for the caryophyllenes indicated by the above, together with that of the hydrochloride, to indicate the transpositions which occur —... 

Formula (1) would thus indicate the natural dextro-caryophyllene of clove stems formula (2) indicates the highly laevo-rotatory caryophyllene resulting from regeneration by means of pyridine, and (3) may represent the a-caryophyllene of Deussen. 

Caryophyllene nitrosochloride, (CjgHgJjN OoCL, is obtained when a mixture of the sesquiterpene, alcohol, ethyl acetate, and ethyl nitrite is cooled in a freezing mixture, and then treated with a saturated solution of hydrochloric acid in alcohol. The reaction mass is allowed to stand on ice for an hour and is then exposed to sunlight. Thus prepared it melts at about 158° to 163°, and can be separated into two compounds, one being that of a-caryophyllene and the other that of yS-caryophyllene Deussen s sesquiterpenes of natural caryophyllene from clove oil), a-caryophyllene nitrosochloride melts at 177", and /3-caryophyllene nitrosochloride at 159°. They can be separated by fractional crystallisation. The corresponding a-nitrolbenzylamine melts at 126° to 128°, and the /3-nitrolbenzylamine at 172° to 173°. The bimolecular formula given above is probable but not certain. 

Deussen considers that the nitrosate above described is identical with that of a-caryophyllene, and that the nitrosochloride is identical with that of the same sesquiterp ene. He therefore considers that iinmulene is, at all events i in greater part, actually a-caryophyllene. 

The first observation is the similarity between the chemical compositions of both the Boswellia carteri and Boswellia sacra. For these three olibanum samples, a-pinene (2), (3-myrcene (8) and limonene (14) are the predominant monoterpenes. p-Caryophyllene (73) is the major sesquiterpene besides a-copaene (65), a-humulene (also called a-caryophyllene) (78) and caryophyllene oxide (95). The characteristic olibanum compounds isoincensole and isoincensole acetate (128) together with cembrene A (120) are the main diterpenes. 

Wie und in welcher Reihenfolge diese verwickelten Reaktionen ver-laufen, ist experimentell und theoretisch noch ungeklart. Sukh Dev (37) erhielt aus dem Humulen (a-Caryophyllen) durch Cyclisierung mit p-Toluolsulfonsaure ein Bicyclohumulen, das bei der Dehydrierung mit Palladiumkohle ebenfalls ein Azulen — wohl Guajazulen — bildete. 

Caryophyllenes are a class of sesquiterpenes that protect plants against insects, and have a quite unusual structure a four membered-ring fused to a medium-sized ring of nine carbon atoms. There are two isomers which only differ in the configuration of an endocyclic double bond the so-called a-caryophyllene ( -isomer) (la) and the corresponding (Z)-isomer the P- or isocaryophyllene (lb). 

N.A. Caryophyllen, isobetanine, isoprebetanine 100 Treat catarrh, dyspepsia, granular conjunctivitis, and rheumatism. 

Analysis TM290 was used by Corey ( . Amer. Chem. Soc,, 196, 86, 1652) in his synthesis of a-caryophyllene alcohol. Again, only one disconnection is very productive ... 

Though the rearrangement step transforms a stable tertiary cation into a less stable secondary cation, relief of strain in expansion from a four- to a five-membered ring makes the alkyl migration favourable. In 1964, E.J. Corey published a synthesis of the natural product a-caryophyllene alcohol that made use of a similar ring expansion. Notice the photochemical [2+2] cycloaddition (Chapter 35) in the synthesis of the starting material. 

Although isocomene (668), mentioned above, is included in this section it is likely that this hydrocarbon, together with modhephene (679), is derived from a caryophyllene-type precursor. Indeed one can conceive of a biogenetic pathway (Scheme 87) which encompasses both these compounds as well as botrydial (681), quadrone (682), and the recently isolated senoxydene (304). " To lend partial credence to this scheme is the fact that the hydrocarbon (680) is a product of acid-catalysed rearrangement of isocaryophyllene (678). ... 

Other products which were isolated from this study were the related fused 5,7-ring molecules (117)-(119), together with a-caryophyllene alcohol (116 Scheme 13). 

The ready availability of four-membered rings of defined stereochemistry from enone-alkene photocycloadditions has been the origin of several syntheses which employ Wagner-Meerwein rearrangements in subsequent steps. This is exemplified by a neat and very short synthesis of a-caryophyllene alcohol (40) from cyclopentene and 3-methylcyclohexenone which was described some years ago (see Scheme 15). The rearrangement in 40% sulfuric acid proceeded remarkably smoothly. A short synthesis of iso-comene (41 Scheme 16) also Illustrates this strategy... 

These compounds co-occur in the essential oil of Cedrus atlantica and it is interesting to note that a-caryophyllene alcohol (62) (obtained for the first time as a natural product) and the epimeric himachalene epoxides (63 a and b) have also been identified as co-metabolites. ... 

Here again the considerations are not theoretical they are entirely practical. One of the results of the capricious use of terms in the past has been that single substances are designated by several unrelated names, and that the same name is used for several unrelated substances. Where this has been the case, it may be necessary to unravel some tangled threads. Moreover, it is necessary to watch current literature very closely. Only very recently, for example, was it shown that a-caryophyllene and humulene are identical, although this had been suspected for some time. 

This ring-expansion process is quite useful when applied to polycyclic systems. Corey treated 57 with 40% sulfuric acid and isolated the rearranged alcohol, a-caryophyllene alcohol (60). The initially formed cyclo-butylcarbinyl cation (58) rearranged to the cyclopentyl cation (59), which was trapped by water to give 60. 

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