Volumen XLV, Fasciculus 11 (1962)

Distillation foreruns from East Indian sandalwood oil (Santalum album L.), representing 5–8% of the oil, have been investigated using fractional distillation, preparative column chromatography, gas liquid chromatography (GLC.), and chemical treatments. This allowed the isolation and characterization by their spectral data of 46 compounds. 32 of them were newly identified sandalwood oil constituents including 4 novel substances: santalone (2), 4‐methylcyclohexa‐1,3‐dien‐1‐yl methyl ketone (4), 5,6‐dimethyl‐5‐norbornen‐exo‐2‐ol (7), and (E)‐5‐(2,3‐dimethyl‐3‐nortricyclyl)‐pent‐3‐en‐2‐one (20). The other constituents identified were 1‐furfuryl‐pyrrole (10) and 10 phenols accompanied by 17 terpene and sesquiterpene derivatives. Endo‐2,endo‐3‐dimethyl‐norbornan‐exo‐2‐ol (6), an α‐santenol (z), precursor, was present in the last group of constituents. The compounds 2, 4, 6, 7, 20 have been synthesized as well as another novel constituent, endo‐2‐mythyl‐3‐methylidene‐norbornan‐exo‐2‐ol (5).

Summary1-p-Menthene-8-thiol (B) is shown to be a potent character-donating constituent of grapefruit juice, in which it occurs at the ppb-level or below. A convenient synthesis is described for this terpene-thiol, apparently the most powerful flavor compound ever found in nature.The peel and juice oils from Citrus spp. are important flavoring ingredients for the food and beverage industries [l]. Considerable research work has already been done in order to identify many individual constituents of these natural flavors. Since about 1950, both cold-pressed oil and juice of grapefruit (Citrus paradisi MACFAYDEN) have been investigated and a total of some 126 volatile constituents were characterized [2] (not including less volatile components such as coumarins [3], sugars, hydroxy-acids, and other water-soluble substances which do not contribute substantially to the specific grapefruit flavor). Among the volatiles identified, nootkatone (A) [4] is considered as a primary flavor-impact compound in grapefruit, although it also occurs in most other Citrus spp. Recently, however, authors have questioned the true flavoring importance of A, even whether or not this ketone is necessary for good grapefruit flavor [5] [6]. In any case, there is no doubt that still unidentified compounds co-occur with nootkatone (A) in grapefruit flavor and contribute importantly to the flavor and aroma of grapefruit oil and juice [5-71.We now report that a prominent and unexpected representative of these hitherto unknown flavor components is I -p-menthene-8-thiol (B) [S]. When adequately diluted, this novel, powerful flavor-impact compound displays a genuine, unmistakable aroma of fresh grapefruit juice (in which it naturally occurs at or below the ppb-level). The identification of B practically settles the long-standing problem of synthetically reproducing the full-bodied flavor of fresh grapefruit juice. Other previously identified S-compounds in grapefruit were hydrogen sulfide [9] Patent applications relative to the use of 1-p-menthene-8-thiol (B) have been filed in several countries by Firmenich SA, Geneva

Damascenone an odoriferous ketone isolated in minute amounts from Bulgarian rose oil (Rosa damascena Mill.) is shown to be trans‐2,6,6‐trimethyl‐1‐crotonoyl‐cyclohexa‐1, 3‐diene (I). A synthesis starting from beta;‐cyclocitral is described for this conspicuous constituent of rose oil, which displays a powerful fragrance. The synthesis of four related, more saturated ketones, damascones , is also described.

Aus Grapefruit‐Saft wurde die Titelverbindung (IV) als stärkster bisher bekannter in der Natur vorkommender Aromastoff isoliert.