Sabinene hydrate, cis

The use of enantiomers as additional markers for taxonomic characterization of aromatic plants may be very helpful. The differences in the enantiomeric distribution of trans- and cis- sabinene hydrates in two Origanum species enable the species to be distinguished in spite of their similar essential oil compositions. A further study on the natural variation of the enantiomeric composition within a wild population may be carried out in order to examine the stability in a taxon (including the possible presence of chemotypes). The enantiomeric ratio of essential oil components is a reliable parameter for assessing quality because it may be indicative of adulteration, contamination, aging, shelf life, technological process and the botanical source of a specific chiral compound. ... 

The bicyclic monoterpenes cis-sabinene hydrate and cit-sabinene hydrate acetate are known as the major and original flavor compounds of marjoram Origanum majorand) Relatively large quantities of cis- and trans-sabinene hydrate were detected in the genus Origanum m-Sabinene hydrate acetate was found in relatively large amounts in solvent and CO2 extracts of O. and as a minor component in hydro-... 

Larkov O, Dunkelblum E, Zada A, Lewinsohn E, Freiman L, Dudai N, Ravid U, Enantiomeric composition of trans- and cis- sabinene hydrate and their acetates in five Origanum spp., Flavour Fragr/22 109—114, 2005. 

Novak J, Bitsch C, Pank F, Langbehn J, Franz CM, Distribution of the cis-sabinene hydrate acetate-chemotype in accessions of marjoram Origanum majorana L.), Euphytica 127 69-74, 2002. 

Composition Main constituents are a- and y-terpinene, terpinene-4-ol, a-terpineol, linalool, linalyl acetate and cis-sabinene hydrate. The latter, along with its transisomer and terpinene-4-ol, is considered as typical aroma carrier of sweet marjoram. The quantitative composition, especially of oils of uncertain botanical origin, varies considerably ]155]. Oils from India contain eugenol, methyl chavicol and geraniol in marked amounts ]156], while these compounds are negligible or absent in European oils. Commercial oils from Turkey contain considerable amounts of carvacrol, some up to 80% [157]. Also the production process can influence the oil composition, e.g. cis-sabinene hydrate is partly converted to terpinene -ol during steam distillation. The genuine plant additionally contains cis-sabinene hydrate acetate, which is almost totally hydrolysed in the steam-distilled oil [158]. 

Bicydo[3,l)0]hexanes.—Acid-catalysed ethanolysis (80% EtOH) of cis-sabinene hydrate (28) and its trans-isomer (of unspecified chiralities) yields 30% of p-menth-l-en-4-ol it would be of interest to know its optical purity in view of the reports that (+)-trans-sabinene hydrate may be isomerized to p-menth-1- ... 

Groendahl, E. Ehlers, B.K (2008). A new cis-sabinene hydrate chemotypre detected in large Thyme (Thymus pidegioides L.) growing wild in Denmark. Journal of Essential Oil Research, Vol.20, No.l, 0anuary/February 2008), pp. 40-41, ISSN 1041-2905... 

Majorana hortensis) Tetrata DE 1999 Ployploid cis-Sabinene-hydrate... 

Gaoni, Y. Base Induced Isomerizations of y,6-Epoxyketones - II. Syntheses in the Thujane Series. /),L-Sabina Ketone and D.L-Cis Sabinene Hydrate. Tetrahedron 28, 5525 (1972). 

Novak J, Bitsch C, Langbehn J, Pank F, Skoula M, Gotsiou Y, Franz CM, Ratios of cis- and tra wr-sabinene hydrate in Origanum majorana L. and Origanum microphyllum (Bentham) Vogel, Biochem Syst Ecol 28 697—704, 2000. 

Thujane-type monoterpenes, unusual monoterpenes with a cyclopropane ring in a bicyclo[3.1.0] skeleton, are formed from the terpinen-4-yl cation directly or via the sabinyl cation. Important members include a-thujene 52, sa-binene 53, the cis isomer 54 of sabinene hydrate, sabinol 55, sabinylacetate 56, a-thujone 57, -thujone 58 and isothujanol 59 (Structure 4.13). 

Wilkins et al. [89] describe the use of GC-FTIR to separate and identify some very similar cyclic alcohols, the pairs of cis and trons-menth-2-ene-l-ols, sabinene hydrates, and terpineols. The 800-1500 cm region gave distinct fingerprints that differentiated each isomer from the other. 

Cis- and trans-sabinene hydrate, formerly called thujanol, are the two main tertiary alcohols. They are t5rpical compounds in the marjoram oil Origanum majorana) and a specific chemot5tpe of thyme oils Thymus vulgaris). Sabinol is found in the oil of Juniperus sabina and other Juniperus species. These alcohols occur as free compounds or as acetates. 

Acid catalyzed rearrangements of cis- and trani-sabinene hydrate yielded terpinen-4-ol (56%), y-terpinene (18%), a-terpinene (9%), terpinolene (3%), p-cymene (1%), a-terpineol (1%), and E/Z-p-menth-2-en-l-ol (1%) [41]. 

Owing to its long-standing limitations, the Stetter reaction has been utQized in a limited number of syntheses (Figure 18.4). P-Unsubstituted acceptors have been used en route to cis-jasmone and dihydrojasmone [57], roseophilin (81) [58], ( )-trans-sabinene hydrate [59], monomorine I [60], and haloperidol [61], while a doubly activated Michael acceptor was used to access an intermediate in the synthesis of atorvastatin [62]. Less reactive P-substituted acceptors could be used intramolecularly in the syntheses of ( )-hirsutic acid C (82) [63], ( )-platensimycin (83) [64], and polycyclic ether arrays [65], as well as in the enantioselective formation of a spirocyclic intermediate toward FD-838 (84) [66]. 

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