Cyclopropyl Scaffold: A Generalist for Marketed Drugs.

In recent decades, much attention has been given to cyclopropyl scaffolds, which commonly exist in natural products and synthetic organic molecules. Clinical drug molecules with cyclopropyl rings are an area of focus in therapeutic research due to their interesting chemical properties and unique pharmacology activity. These molecular drugs against different targets are applicable in some therapeutic treatment fields including cancer, infection, respiratory disorder, cardiovascular and cerebrovascular diseases, dysphrenia, nervous system disorders, endocrine and metabolic disorders, skin disease, digestive disorders, urogenital diseases, otolaryngological and dental diseases, and eye diseases. This review is a guide for pharmacologists who are in search of valid preclinical/clinical drug compounds where the progress, from 1961 to the present day, of approved marketed drugs containing cyclopropyl scaffold is examined.

Triazol: a privileged scaffold for proteolysis targeting chimeras.

Current traditional drugs such as enzyme inhibitors and receptor agonists/antagonists present inherent limitations due to occupancy-driven pharmacology as the mode of action. Proteolysis targeting chimeras (PROTACs) are composed of an E3 ligand, a connecting linker and a target protein ligand, and are an attractive approach to specifically knockdown-targeted proteins utilizing an event-driven mode of action. The length, hydrophilicity and rigidity of connecting linkers play important role in creating a successful PROTAC. Some PROTACs with a triazole linker have displayed promising anticancer activity. This review provides an overview of PROTACs with a triazole scaffold and discusses its structure-activity relationship. Important milestones in the development of PROTACs are addressed and a critical analysis of this drug discovery strategy is also presented.

Concise synthesis of 2-methoxyestradiol from 17ß-estradiol through the C(sp2)-H hydroxylation.

A four-step route for the synthesis of 2-methoxyestradiol (5) starting from 17ß-estradiol (1) has been achieved with a 51% overall yield. The key step was the ruthenium-catalyzed ortho-C(sp2)-H bond hydroxylation of aryl carbamates. Using dimethyl carbamate as the directing group, [RuCl2(p-cymene)]2 as the catalyst, PhI(OAc)2 as the oxidant and trifluoroacetate/trifluoroacetic anhydride (1:1) as the co-solvent, the hydroxyl group could be singly installed at the 2-position of 3-dimethylcarbamoyloxyestradiol (2) with 65% yield. Subsequent methylation of hydroxy and removal of dimethyl carbamate afforded 2-methoxyestradiol (5).