Synthesis and evaluation of novel amide amino-ß-lactam derivatives as cholesterol absorption inhibitors.

The ß-lactam cholesterol absorption inhibitor ezetimibe is so far the only representative of this class of compounds on the market today. The goal of this work was to synthesize new amide ezetimibe analogs from trans-3-amino-(3R,4R)-ß-lactam and to test their cytotoxicity and activity as cholesterol absorption inhibitors. We synthesized six new amide ezetimibe analogs. All new compounds exhibited low toxicity in MDCKIIwt, hNPC1L1/MDCKII and HepG2 cell lines and showed significant inhibition of cholesterol uptake in hNPC1L1/MDCKII cells. In addition, we determined the activity of the three compounds to inhibit cholesterol absorption in vivo. Our results demonstrate that these compounds considerably reduce cholesterol concentrations in liver and small intestine of mice. Thus, our newly synthesized amide ezetimibe analogs are cholesterol absorption inhibitors in vitro and in vivo.

Novel amino-ß-lactam derivatives as potent cholesterol absorption inhibitors.

Two new trans-(3R,4R)-amino-ß-lactam derivatives and their diastereoisomeric mixtures were synthesized as ezetimibe bioisosteres and tested in in vitro and in vivo experiments as novel ß-lactam cholesterol absorption inhibitors. Both compounds exhibited low cytotoxicity in MDCKII, hNPC1L1/MDCKII, and HepG2 cell lines and potent inhibitory effect in hNPC1L1/MDCKII cells. In addition, these compounds markedly reduced cholesterol absorption in mice, resulting in reduced cholesterol concentrations in plasma, liver, and intestine. We determined the crystal structure of one amino-ß-lactam derivative to establish unambiguously both the absolute and relative configuration at the new stereogenic centre C17, which was assigned to be S. The pKa values for both compounds are 9.35, implying that the amino-ß-lactam derivatives and their diastereoisomeric mixtures are in form of ammonium salt in blood and the intestine. The IC50 value for the diastereoisomeric mixture is 60 µM. In vivo, it efficiently inhibited cholesterol absorption comparable to ezetimibe.

Aminoethyl-substituted indole-3-acetic acids for the preparation of tagged and carrier-linked auxin.

Indole-3-acetic acid is an indispensable hormone (auxin) in plants and an important metabolite in humans, animals, and microorganisms. Here we introduce its 5- and 6-(2-aminoethyl)-derivatives for use in the design of novel research tools, such as immobilized and carrier-linked forms of indole-3-acetic acid and its conjugates with biochemical tags or biocompatible molecular probes. The aliphatic nitrogens of 5- and 6-(2-aminoethyl)indole were acetylated and the products were converted to the corresponding 3-(N,N-dimethylamino)methyl derivatives (gramines). These were reacted with cyanide. Saponification of the resulting acetonitriles was accompanied by N-deprotection to yield 5- and 6-(2-aminoethyl)indole-3-acetic acids. The latter were chemically stable and could be linked, via their amino groups, and without prior protection of their carboxyl moieties, to bovine serum albumin and to biotin, including appropriate spacer modules. One of the protein conjugates was used to elicit the formation of monoclonal antibodies, which were evaluated using the biotin conjugates in an enzyme-linked immunosorbent assay employing streptavidin-coupled alkaline phosphatase, and thus shown to recognize predominantly the indole-3-acetic acid moiety.