Patchoulenes

On dehydration it yields patchoulene, a sesquiterpene which has not been i investigated. 

In fact, a "diabolic confabulation" of two rearrangements, one in the course of degradation of patchouli alcohol to a-patchoulene (4-5) and another one in the... 

Scheme 13.6.8 shows how compound 38. which has the basic bicyclo[5.3.1]undecane ring system of taxol, can be prepared by this procedure from a taxusin intermediate readily available from camphor in either enantiomeric form [15b]. Compare the structure of 40 with a-patchoulene 5, in Scheme 1.1 (pag. 10). 

Although cedranoid sesquiterpenes have earlier been synthesized, a renewed interest in alternative methods for elaborating these frameworks has arisen. The stereo-specific approach to (x-cedrene and a-patchoulene skeletons designed by Deslong-champs and summarized in Scheme XLIII is a case in point Beginning with the Stork-Clarke intermediate 559, the tetracyclic cyclopropyl diketone 560 was elaborated via a series of standard transformations. Treatment of 560 with three equivalents of sodium methoxide in methanol at room temperature for 20 min... 

Closely related to Java patchouli (P. heyneonus) known as false patchouli and sometimes used to produce an essential oil. The true oil is a viscous amber colour with a sweet earthy odour. Its main component is patchouli alcohol (up to 40%) with bulnesene (14-17%), seychellene (8.5-9.5%), caryophyllene (3-4%), 3-patchoulene (2.7-4%). There are a variety of attributed therapeutic properties. For the mind it is said to be a grounding oil helpful for those who feel depressed, detached and exhausted. Applied to the circulation it is considered stimulating, as a diuretic and for skin healing in conditions like acne and eczema. It is often used as a fixative in oriental perfumes, and a deodorizer as it masks unpleasant smells. Due to its very strong odour it is advisable to use in low proportions in a blend. Generally considered to be a safe oil as it is non-irritant and non-sensitizing. 

Erraan and Stonehave devised a new method for the construction of the tricyclic skeleton associated with such sesquiterpenes as a-patchoulene (438) and cyperene (439). The route they employed was the formation of the acid-ester (440 R = OH) by a Diels-Alder reaction of 3-ethoxycarbonyl-2,4-dimethyl-penta-1,3-diene with acrylic acid. The corresponding diazo-ketone (440 R = CHN2), on treatment with boron trifluoride etherate, gave the keto-esters (441) and (442) directly. This direct acid-catalysed cyclization proved to be more efficient than the conventional copper-catalysed thermal decomposition of (440 ... 

Oil of Patchouli. Patchouli oil. Essential oil from leaves of several Labiatae species. The commercial oil is obtained from the cultivated species, Pogoslemon cablin (Blanco) Benth. (P. patchouly Pellet, var suavis Hook, f.), Labiatae. Major constituent is patchouli alcohol (cj. i / minor constituents include patchoulene. azulene, eugeno], and several unidentified sesquiterpenes Pfau, Planner, Helv. 

Analysis of rhizomes of cultivated plants showed significantly higher content of valepotriates and patchouli alcohol than reported in wild plants. The maximum valepotriate content was found at 4.3% (dry matter basis) under nylon net shade. A marked difference in other constituents of ar-curcumene, (3-patchoulene, and y-patchoulene was found in higher percentage than reported from wild plants [62]. 

---