Magnesium dicarboxylates promote the prenylation of phenolics that is extended to the total synthesis of icaritin.

The prenylation of phenolic substrates promoted by magnesium dicarboxylates was developed. An investigation of the scope demonstrated that substrates with electron-donating group(s) gave better yields than those with electron-withdrawing group(s). Although the conversions of all substrates were higher in MeCN than in DMF, DMF was still the favorable solvent for polyphenolic substrates since MeCN would cause the generation of cyclized by-products (6) and reduce the yield of 3. The regio-selectivity of ortho- vs. para-prenylation (3'vs.3'') for those para-unoccupied substrates was also solvent dependant. DMF produced mainly ortho-products but with poor conversions. On the other hand, MeCN generated mainly para-products, along with minor ortho-products. Mechanistic study of the prenylation provided evidence for the nucleophilic addition/substitution of the phenolic substrate to the alkyl halide in the presence of the magnesium dicarboxylates. The proto application of this method in the total synthesis of icaritin through the prenylation of 2,4,6-trihydroxyacetophenone, followed by the reaction with benzaldehyde to afford the flavonol, was successful, with a total yield of 33%.

The Homocoupling Reaction of Aromatic Terminal Alkynes by a Highly Active Palladium(II)/AgNO3 Cocatalyst in Aqueous Media Under Aerobic Conditions.

A new and efficient Pd(II)/AgNO3-cocatalyzed homocoupling of aromatic terminal alkynes is described. Various symmetrical 1,4-disubstituted-1,3-diynes are obtained in good to excellent yields. This protocol employs a loading with relatively low palladium(II) in aqueous media under aerobic conditions.

Synthesis of aryloxyacetamides from arylboronic acids and 2-bromoacetonitrile promoted by alkaline solutions of hydrogen peroxide.

A novel and metal catalyst-free synthesis of aryloxyacetamides from the corresponding arylboronic acids and 2-bromoacetonitrile promoted by alkaline solutions of hydrogen peroxide has been developed involving an oxidation-reduction of eco-friendly H2O2 with simultaneous reaction ipso-hydroxylation of arylboronic acid and hydration of the nitrile. This protocol is compatible with sensitive substituents attached to the arylboronic acid and provides desired products in moderate to good yields in pure water.

[Processing method and HPLC fingerprint of charred radix Scutellariae].

OBJECTIVE: To investigate the process and HPLC fingerprint of Charred Radix Scutellariae, and lay a foundation of Charred Radix Scutellariae quanlity control mode. METHOD: Select HPLC-UV fingerprint. Chromatogram condition: Hypersil C18 column (5.0 mm x 200 mm, 5 microm), mixtures of methanol, 0.4% phosphoric acid and acetonitrile as mobile phase in a gradient mode. Flow rate: 1.0 mL x min; Detection wavelength was set at 277 nm. RESULT: There were no evident differences among Charred Radix Scutellariae that were normatively manufactured and processed. CONCLUSION: This test proves the process is feasible, this method recurs well and can be used to provide scieitific basis for the normative process and quanlity control mode of Charred Radix Scutellariae.