Structure optimization of a leukotriene D4 antagonist by combinatorial chemistry in solution

“On-water” synthesis of novel trisubstituted 1,3-thiazolesviamicrowave-assisted catalyst-free domino reactions

A clean, efficient and catalyst-free multicomponent domino reaction of arylglyoxals, cyclic 1,3-dicarbonyls and thioamides in aqueous media under microwave conditions is reported.

Novel nitrogen-enriched oridonin analogues with thiazole-fused A-ring: protecting group-free synthesis, enhanced anticancer profile, and improved aqueous solubility

Oridonin (1), a complex ent-kaurane diterpenoid isolated from the traditional Chinese herb Isodon rubescens , has demonstrated great potential in the treatment of various human cancers due to its unique and safe anticancer pharmacological profile. Nevertheless, the clinical development of oridonin for cancer therapy has been hampered by its relatively moderate potency, limited aqueous solubility, and poor bioavailability. Herein, we report the concise synthesis of a series of novel nitrogen-enriched oridonin derivatives with thiazole-fused A-ring through an efficient protecting group-free synthetic strategy. Most of them, including compounds 7-11, 13, and 14, exhibited potent antiproliferative effects against breast, pancreatic, and prostate cancer cells with low micromolar to submicromolar IC50 values as well as markedly enhanced aqueous solubility. These new analogues obtained by rationally modifying the natural product have been demonstrated not only to significantly induce the apoptosis and suppress growth of triple-negative MDA-MB-231 breast cancer both in vitro and in vivo but also effective against drug-resistant ER-positive MCF-7 clones.

Combinatorial chemistry as a tool for drug discovery

The question 'will combinatorial chemistry deliver real medicines' has been posed [96]. First it is important to realise that the chemical part of the drug discovery process cannot stand alone; the integration of synthesis and biological assays is fundamental to the combinatorial approach. The results presented in Tables 3.1 to 3.8 suggest that so far smaller directed combinatorial libraries have obtained equivalent results to those obtained previously from traditional medicinal chemistry analogue programs. Unfortunately, because of the long time it takes to develop pharmaceutical drugs there are no examples yet of marketed drugs discovered by combinatorial methods. There are interesting examples where active leads have been discovered from the screening of the same library against multiple targets (e.g. libraries 13, 39, 43, 66, 71 and 76). It is now possible to handle much larger libraries of non-oligomeric structures and the chemistry required for such applications is becoming available. Whether combinatorial approaches can also be adapted to deal with all the other requirements of a successful pharmaceutical (lack of toxicity, bioavailability etc.) is open to question but there are already examples such as cassette dosing [235-237]. However we can still be optimistic about the possibility of larger libraries producing avenues of investigation for the medicinal chemist to develop into real drugs. Combinatorial chemistry is an important tool for the medicinal chemist.

Solution-phase combinatorial chemistry

The use of solution phase techniques has been explored as an alternative to solid-phase chemistry approaches for the preparation of arrays of compounds in the drug discovery process. Solution-phase work is free from some of the constraints of solid-phase approaches but has disadvantages with respect to purification. This article will also illustrate some of the advances made in recent years in solution phase array chemistry including using supported reagents and simple extractive protocols for the effective preparation of high quality samples.

Comprehensive survey of chemical libraries yielding enzyme inhibitors, receptor agonists and antagonists, and other biologically active agents: 1992 through 1997

This review is a historical accounting of chemical libraries from which biologically active agents have been obtained. The comprehensive tabulation includes citations as early as 1992, when the first descriptions of biologically active libraries were disclosed, and continues through 1997. Four tables are provided listing libraries screened against (1) proteolytic enzymes, (2) non-proteolytic enzymes, (3) G-protein coupled receptors (GPCRs), and (4) other targets not classified in the first three tables (e.g. non-GPCRs, integrins, antiinfectives). A name, generic structure, and size is provided for each library citation, accompanied by the molecular screen and the structure and potency of the most active library member. In total, 86 libraries are presented with 60% of the contributions reported from pharmaceutical and biotechnology companies. Approximately 70% of the libraries have used alpha-amino acid synthons in their construction and 85% of the libraries include one or more amide bonds.