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

Twenty-two new sodium monosubstituted phenylsulfamates XC6H4NHSO3−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 XC6H4– 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 Esolv 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, Esolv, and the CPK measurements, x (length) and z (width) of XC6H4–. Apparently, for sweetness, the CPK measurement x of XC6H4– 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.