Conformational evaluation of some 4-deoxyhex-4-enopyranose derivatives and their use in the preparation of a previously undescribed class of 3-thio-L-sorbopyranosides and their 6-C-methoxy analogues.

A new series of thio-substituted sugars were synthesised relying on the totally regio- and stereoselective cycloaddition of 4-deoxyhex-4-enopyranose derivatives to 'in situ' generated oxothiones. Conformational studies of the above unsaturated sugars showed a marked prevalence of the all-axial conformer.

Design, synthesis and biological activity of carbohydrate-containing peptidomimetics as new ligands for the human tachykinin NK-2 receptor.

Enantiopure cycloadducts between glycals and alkyl or aryl heterodienes were selected as small, rigid, nonpeptide molecules able to superimpose to the structure of the cyclopeptide tachykinin NK-2 antagonist 1. The presence of three aromatic groups in the pyranose ring resulted essential for NK-2 affinity, while an increase in activity was shown by the corresponding sulfoxides.

Regiocontrolled synthesis of enantiopure 3,3'-thiosubstituted biphenyls.

Sulfenylation of 6,6'-dimethoxy-2,2'-dihydroxybiphenyl, used as a racemic mixture and single enantiomers, by phthalimidesulfenyl chloride afforded the corresponding 3,3'-N,N'-dithiophthalimide with complete regioselectivity. Simple manipulations of the latter compound allowed access to the corresponding bis-thiol or o-thioquinone as useful intermediates for the synthesis of new sulfur-containing open-chain and macrocyclic C(2) enantiopure ligands. The application of this methodology to the preparation of a biphenyl bearing two cysteine units as potential HIV-1 protease inhibitor is also described.