Thia‐bridged triarylamine hetero[4]helicenes (TBTH[4]H) are a peculiar class of geometrically stable [4]helicenes that have shown promising applications as organic electronic materials. Their structure comprises a bis‐phenothiazine moiety, with a nitrogen atom and an aromatic ring in common, forced into a helix‐shaped arrangement by four carbon–sulfur bonds. We describe a detailed study on the scope and application of the electrophilic sulfur insertion path to TBTH[4]H, with particular emphasis on the regioselective preparation of asymmetric (not dissymmetric) derivatives.

M33 is a branched antimicrobial peptide against Gram-negative bacteria. We reported its conjugation with levofloxacin and its antibacterial activity.

We have developed an efficient chemical resolution of racemic hydroxy substituted dithia-aza[4]helicenes (DTA[4]H) 1(OH) using enantiopure acids as resolving agents. The better diastereomeric separation was achieved on esters prepared with (1S)-(−)-camphanic acid. Subsequent simple manipulations produced highly optically pure (≥ 99% enantiomeric excess) (P) and (M)-1(OH) in good yields. The role of the position where the chiral auxiliary is inserted (cape- vs bay-zone) and the structure of the enantiopure acid used on successful resolution are discussed.

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