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Scheme 12. Azidoiodination of Alkenes Using the Oxone/ KI/NaN 3 System Scheme 13. 1,2-Acetoxychlorination of Olefins Chemical Reviews Review dx.

The antioxidant activity of rooibos flavonoids, including the dihydrochalcones aspalathin and nothofagin and their corresponding flavone glycosides, was evaluated using the ABTS radical cation, metal chelating, and Fe(II)-induced microsomal lipid peroxidation assays. Epigallocatechin gallate (EGCG) and Trolox were used as reference standards. Optimized geometric conformers of aspalathin and nothofagin, in addition to calculated physicochemical properties, were considered to explain interaction with the microsomal membrane structure and thus relative potency of the dihydrochalcones. The most potent radical scavengers were aspalathin (IC50 = 3.33 microM) and EGCG (IC50 = 3.46 microM), followed by quercetin (IC50 = 3.60 microM) and nothofagin (IC50 = 4.04 microM). The least effective radical scavengers were isovitexin (IC50 = 1224 microM) and vitexin (IC50 > 2131 microM). Quercetin (IC50 = 17.5 microM) and EGCG (IC50 = 22.3 microM) were the most effective inhibitors of lipid peroxidation. Aspalathin (IC50 = 50.2 microM) and catechin (IC50 = 53.3 microM) displayed similar potencies. Nothofagin (IC50 = 1388 microM) was almost as ineffective as its flavone glycoside analogues.

Ursolic acid (UA), belongs to a group of pentacyclic triterpenoids and is known to possess some very interesting biological properties. Protocols have been developed in order to synthesize bioactive UA analogs which have resulted in numerous ursolic acid analogs being synthesized during the period 2012-2016. Ursolic acid and its analogues can be employed to treat various cancers, inflammatory diseases, diabetes, Parkinson's disease, Alzheimer's disease, hepatitis B, hepatitis C and AIDS to mention but a few. Areas covered: This review covers patents on therapeutic activities of ursolic acid (UA) and its synthetic derivatives published during the four year period 2012-2016. A discussion about structure-activity relationships (SAR) of these analogs is also included. Expert opinion: Ursolic acid and its synthetic derivatives demonstrated excellent anticancer, antidiabetic, antiarrhythmic, anti-hyperlipidemic, antimicrobial, anti-hypercholesterolemic, and anti-cardiovascular properties. Additionally, various ursolic acid analogues have been synthesized through modification at positions C-OH, C-OH and CCOH. It is noteworthy that the C-17 amide and amino analogs of UA possessed better anticancer activity compared to the parent compound (UA). Most importantly, UA has the potential to conjugate with other anticancer drugs or be transformed into its halo derivatives since this will greatly facilitate scientists to get lead compounds in cancer drug discovery.

This review aims to collect and discuss the synthetic applications of meta-chloroperbenzoic acid (mCPBA) over the past few decades.

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