(5R^*, 9S^*)‐ and (5R^*, 9R^*)‐2,2,9‐Trimethyl‐1,6‐dioxaspiro[4.4]non‐3‐ene and their Dihydro Derivatives as New Constituents of Geranium Oil

Abstract

Summary(5R *,9S *)-and (5R *,9R *)-2,2,9-Trimethyl-1,6-dioxaspiro[4.4]non-3-ene ( l a and l b resp.) and their dihydro derivatives 2a and 2b are described as new constituents of geranium oil. The structures and configurations of la, lb, 2a, and 2b are based on spectra interpretation and syntheses. Also some other monoterpenoid constituents identified in the same boiling range are discussed.

Identification of the Characteristic Odorants in Fresh Rhizomes of Ginger (Zingiber officinale Roscoe) Using Aroma Extract Dilution Analysis and Modified Multidimensional Gas Chromatography-Mass Spectroscopy

“…Compound 13 was determined to be 2-(2',3'-epoxy-3'methylbutyl)-3-methylfuran on the basis of its authentic mass spectra and Kovats index. Compound 13, with a green, earthy, and citrus-like odor, was previously found in geranium oil (Kaiser, 1984), but is identified here for the first time in ginger. Compounds 10 and 14 (Table 2) were identified as the same compounds, (Z)-and (E)-3,7-dimethyl-3,6-octadienal, which were isolated from a cubeba oil.…”

“…Preparation of 2-(2',3,-Epoxy-3'-methylbutyl)-3-methylfuran. This compound was synthesized by the same previously described method (Kaiser, 1984).…”

An introduction to the scent of cacti

“…This is probably the result of a combination of chemical rearrangements and a loss of dimethyl disulphide due to column break-through. Thus, the biological origin of several sulphides in the scents of batpollinated cacti must be questioned, leaving only methyl thioacetate (15), dimethyl disulphide (16) and dimethyl disulphide monosulphone (17) as genuine natural products.…”