Diterpenoid sweeteners. Synthesis and sensory evaluation of stevioside analogues with improved organoleptic properties.

Congeneric series of stevioside (1) and rebaudioside A (3) analogues have been prepared. It was found that the bitter-taste component endogenous in the natural compounds 1 and 3 may be eliminated by increase in molecular hydrophilic character. Through the series of compounds prepared, bitter-taste character was correlated with k', a chromatographic indicator of gross hydrophilicity. An analogue (11) of stevioside, shown chromatographically to be of increased hydrophilicity, was prepared and found to exhibit no bitter-taste character. Similarly an analogue (13) of rebaudioside A, having increased polarity, was prepared and found not to exhibit any bitter taste. The rebaudioside A analogue 13 was determined to have higher potency than 11 is suggested as a potential non-nutritive sweetener for food applications.