From the commercial extract of the leaves of Stevia rebaudiana , a diterpene glycoside was isolated which was characterized as 13-[(2- O -β-D-glucopyranosyl-β-D-glucopyranosyl)oxy] ent -kaur-16-en-19-oic acid-(2- O -β-D-glucopyranosyl-β-D-glucopyranosyl) ester ( 1 ); also known as rebaudioside E. The complete 1 H and 13 C NMR assignments of rebaudioside E was achieved by the extensive 1D and 2D NMR ( 1 H and 13 C, COSY, HMQC, HMBC) as well as mass spectral data. Further, hydrolysis studies were performed on rebaudioside E using acid and enzymatic studies to identify aglycone and sugar residues in its structure.

The synthesis of the high-potency sweetener, NC-00637 (1), required selective preparation of the gamma-protected glutamic acid. Coupling of the three components could be performed in any order, but the final route involved N-acylation of the protected L-glutamic acid with the acid chloride derived from (S)-2-ethylhexanoic acid. Activation of the alpha-carboxyl group allowed condensation with 5-amino-2-cyanopyridine (4). Saponification of the gamma-ester 19 then provided the sweetener 1.

Reactions of benzotriazolylacetic acid 7 dianion with electrophiles gave 2-benzotriazolylcarboxylic acids 9a-c. Dianions of 9a-c were transformed with acid halides to alpha-benzotriazolylketones 12a-i.

The pyridine moiety within the high-potency sweetener, NC-00637 (1), 5-amino-2-cyanopyridine (4), was prepared from 2-hydroxy-5-nitropyridine (10). The sequence involved the conversion of the hydroxy group to bromide followed by substitution with cyanide to give 2-cyano-5-nitropyridine (8). Reduction of the nitro group proved to be troublesome when catalytic hydrogenation was used. Iron with an acid gave a reproducible reaction that could be used at scale.

The synthesis of the high potency sweetener candidate NC-00637 (1) required large quantities of (S)-2-methylhexanoic acid (2). This acid was first prepared in small quantities by the use of chiral auxiliaries. For large quantities, resolution by classical means and an enzymatic method were investigated. Asymmetric hydrogenation provided a workable solution.

Abstract α‐Hydroxylation of a ketone using o ‐iodosylbenzoic acid: α‐hydroxyacetophenone via the α‐hydroxy dimethylacetal reactant: Anhydrous methanol (80 mL) product: α‐Hydroxyacetophenone. intermediate: 6.0 g (0.33 mol) of α‐hydroxy dimethylacetal

A total of 397 natural and artificial comprehensively referenced sweeteners were classified by their structures into nine sets. The sweetness potencies were correlated with quantum chemical and other molecular descriptors using the heuristic and the best multi-linear regression methods of the CODESSA software package. QSPR models (two-parameter unless otherwise indicated) emerged for each subclass of sweeteners with R 2 values of 0.835 for 47 aldoximes, 0.959 for 8 acesulfamates, 0.919 for 9 sulfamates, 0.941 for 10 -arylsulfonylalkanoic acids, 0.715 for 27 guanidines (0.802 in a three-parameter correlation), 0.769 for 30 ureas/thioureas (0.888 in a three-parameter correlation), 0.905 for 20 natural sweeteners, 0.957 for 7 miscellaneous sweeteners (one-parameter correlation), 0.688 for 87 peptides (five-parameter correlation). A significant global five-parameter QSPR theoretical model with R 2 of 0.686 for the entire set of sweeteners is presented and discussed with reference to the possible existence of single or multiple sweetness receptors.

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It is possible, using hydrophobic organic acids (such as cinnamate) or hydroxyamino acids (such as serine and tyrosine), to modify the temporal profile of the high-potency sweetener neotame. On the basis of Monte Carlo simulations, it was concluded that it is unlikely that this effect is due to direct interaction between the neotame molecule and the taste modifier. It is shown, using conformational analysis and molecular modeling, that the taste modifiers can adopt low-energy conformers which mimic the proposed active conformation of neotame, which suggests that the modifiers may compete for binding at the receptor site.

Selon l'invention, on modifie le gout et les proprietes physico-chimiques de N-[N-(3,3-dimethylbutyl)-L-α-aspartyl]-L-phenylalanine 1-methylester en utilisant des additifs d'acide hydrophobe. De tels additifs comprennent l'acide benzoique, l'acide valerique, l'acide acetique, l'acide nonoique, l'acide isobutyrique, l'acide cyclohexocarboxylique, l'acide cinnamique, l'acide anisique, l'acide caproique, l'acide isocaproique, l'acide tannique, l'acide citrique, l'acide malique, l'acide lactique, l'acide gluconique, l'acide bitartrique, l'acide fumarique, l'acide adipique et des derives de ces acides. L'invention concerne egalement des procedes de preparation de ces compositions, des produits alimentaires prepares a l'aide de celles-ci, ainsi que des procedes de preparation de ces produits alimentaires a l'aide de ces compositions.