Further studies on the synthesis and tastes of monosubstituted benzenesulfamates. A semi-quantitative structure–taste relationship for the meta-compounds

Abstract

Twenty-two new sodium monosubstituted phenylsulfamates XC 6H 4NHSO 3 −Na + have been prepared and characterized. These compounds, and also para-tolyl- and phenylsulfamate, have been tasted and their taste properties reported. Taste data are now available for 63 such compounds: 19 ortho-, 23 meta- (including phenylsulfamate) and 21 para-. Using CPK molecular models, measurements of the aromatic portion XC 6H 4– have been made. Exclusive/predominant sweetness and reduced sweetness is mainly found with the meta-compounds and a plot derived from the CPK measurements correctly classifies 20 of the 23 (including X=H) meta-compounds into sweet and bitter categories, 12 of the 13 sweet compounds (92%) and 8 of the 10 bitter compounds (80%). Using the PC SPARTAN PRO molecular modelling program, HOMO and LUMO electronic parameters and aqueous solvation energy E solv were calculated. Linear (LDA) and quadratic (QDA) discriminant analyses were carried out on the 23 compounds using various subsets of the CPK measurements and the above SPARTAN-calculated parameters. A 91% classification rate was achieved using QDA and the subset with the parameters LUMO, E solv, and the CPK measurements, x (length) and z (width) of XC 6H 4–. Apparently, for sweetness, the CPK measurement x of XC 6H 4– needs to be in the range ∼5.65⩽ x⩽∼5.95 Å. Using several of the methods developed, taste predictions were made on some unsynthesised meta-phenylsulfamates.