A new electronic-topological investigation of the relationship between chemical structure and ambergris odour.

An electronic-topological approach has been used to define an active ambergris fragment (AAF) which correctly describes the presence (or absence) of the ambergris odour of all 181 compounds investigated. The AAF consists of one oxygen atom and three carbon atoms (alpha, beta, gamma) which are separated by certain key distances and which possess certain atomic charges. The C(alpha) atom must bear at least one hydrogen atom (H(alpha)) which is located at a certain distance from one of the unshared electronic pairs of the oxygen atom.

Structural and electronic origin of meat odour of organic hetero-atomic compounds.

By means of the electron-topologic approach suggested earlier, the structural and electronic features favouring meat odour occurrence are evaluated using 77 organic compounds with known odorant properties as a basis for primary logico-structural analysis. A general fragment of the type XH2 (where X = S, O, N is a hetero-atom) with a certain electronic structure and conformational property is shown to be responsible for the meat odour. The results obtained allow for a prognosis of odorant compounds and their purposeful synthesis.