[Structure: see text] Supramolecular enantiodifferentiating photocyclodimerization of 2-anthracenecarboxylic acid (AC) was performed in the presence of (2S,4S)-4-amino-5-chloro-2-methoxy-N-(1-ethyl-2-hydroxymethyl-4-pyrrolidinyl)benzamide (TKS159), and its stereoisomers were employed as chiral templates. The TKS template provides us with a novel hydrogen-bonding and shielding motif for enantioface-selectively binding an AC molecule. Chiral products 2 and 3 were obtained in good enantiomeric excesses (ee's) of 40% and 40%, respectively.

The first synthesis of nitrogen-bridged terthiophenes (NBTTs) has been achieved by a tandem Buchwald-Hartwig coupling of 3,3',3",4'-tetrabromo-2,2':5',2"-terthiophene. Several NBTT derivatives bearing aryl or alkyl moieties on the N-atoms could be synthesized. Their fundamental electrochemical characteristics and HOMO-LUMO levels were found to be influenced by the substituents on the N-atoms.

The photochirogenesis of 2-anthracenecarboxylic acid (AC) complexed to a hydrogen-bonding template (TKS159) was investigated to obtain mechanistic information on how chirogenesis is achieved for the dimerization of AC. Complexation of AC to TKS159 leads to the shielding of one of the two surfaces of the prochiral AC molecule. The two diastereomeric AC-TKS complexes, i.e., re-AC-TKS and si-AC-TKS, were characterized by changes in the UV-vis, fluorescence, and circular dichroism spectra and excited-state lifetimes. The ee is not simply determined by the diastereomeric ratio of the re- and si-AC-TKS complexes but also depends on the relative lifetimes of the diastereomeric complexes. The relative population of the re and si complexes was calculated from the enantiomeric excess (ee) for the products, taking into account the relative lifetimes of the two complexes. These studies established a protocol that can be used to reveal the mechanism for photochirogenesis by investigating the ground state and the excited state behavior of supramolecular systems.

Due to concerns about the current therapeutic modalities for Helicobacter pylori infection, e.g., the increased emergence of drug-resistant strains and the adverse reactions of drugs currently administered, there is a need to develop an anti-H. pylori agent with higher efficacy and less toxicity. The antibacterial activity of TG44, an anti-H. pylori agent with a novel structural formula, against 54 clinical isolates of H. pylori was examined and compared with those of amoxicillin (AMX), clarithromycin (CLR), and metronidazole (MNZ). Consequently, TG44 inhibited the growth of H. pylori in an MIC range of 0.0625 to 1 g/ml. The MIC ranges of AMX, CLR, and MNZ were 0.0078 to 8 g/ml, 0.0156 to 64 g/ml, and 2 to 128 g/ml, respectively. The antibacterial activity of TG44 against AMX-, CLR-, and MNZ-resistant strains was nearly comparable to that against drug-susceptible ones. In a pH range of 3 to 7, TG44 at 3.13 to 12.5 g/ml exhibited potent bactericidal activity against H. pylori in the stationary phase of growth as early as 1 h after treatment began, in contrast to AMX, which showed no bactericidal activity at concentrations of up to 50 g/ml at the same time point of treatment. TG44 at 25 g/ml exhibited no antibacterial activity against 13 strains of aerobic bacteria, suggesting that its antibacterial activity against H. pylori is potent and highly specific. The present study indicated that TG44 possesses antibacterial activity which manifests quickly and is potentially useful for eradicating not only the antibiotic-susceptible but also the antibioticresistant strains of H. pylori by monotherapy.