Biomedical subjects

Cai-Guang Yang

Publications and source records attributed to Cai-Guang Yang.

8 recordsLinked to original sources

PubMed2006

Brønsted acid catalyzed addition of phenols, carboxylic acids, and tosylamides to simple olefins.

Intermolecular addition of phenols, carboxylic acids, and protected amines to inert olefins can be catalyzed by low concentrations (1-5%) of triflic acid. Functional groups, such as the methoxyl substitution on aromatics, could be tolerated if the concentration of triflic acid and the reaction temperature are controlled appropriately. This reaction provides one of the simplest olefin addition methods and is an alternative to metal-catalyzed reactions.

Journal Article↗

PubMed2006

Gold(I)-catalyzed intra- and intermolecular hydroamination of unactivated olefins.

Ph3PAuOTf catalyzes efficient intra- and intermolecular hydroamination of unactivated olefins with sulfonamides.

Journal Article↗

PubMed2005

Direct repair of the exocyclic DNA adduct 1,N6-ethenoadenine by the DNA repair AlkB proteins.

The exocyclic DNA base adduct 1,N6-ethenoadenine (epsilonA) is directly repaired by the AlkB proteins in vitro.

Adenine↗

PubMed2005

Intramolecular additions of alcohols and carboxylic acids to inert olefins catalyzed by silver(I) triflate.

[reactions: see text] Intramolecular additions of hydroxyl or carboxyl groups to inert olefins catalyzed by simple silver(I) triflate are described. Good to excellent yields can be obtained for a range of substrates under relatively mild conditions. This reaction represents one of the simplest methods to construct cyclic ethers or lactones.

Journal Article↗

PubMed2005

Gold(I)-catalyzed intermolecular addition of phenols and carboxylic acids to olefins.

Ph3PAuOTf can catalyze efficient intermolecular addition of phenols and carboxylic acids to olefins under relatively mild conditions.

Journal Article↗

PubMed2002

Preparing functional bis(indole) pyrazine by stepwise cross-coupling reactions: an efficient method to construct the skeleton of dragmacidin D.

A direct approach for selective construction of properly substituted bis(indole) pyrazine, the skeleton of a marine alkaloid dragmacidin D, has been developed. The key steps involved the regioselective introduction of two indole units, using the palladium(0)-catalyzed Suzuki and the Stille cross-coupling reactions sequentially.

Alkaloids↗

PubMed2002

Enantioselective synthesis of marine indole alkaloid hamacanthin B.

An enantioselective total synthesis of hamacanthin B (1) is described. This synthesis is based on the asymmetric synthesis of (S)-2-azido-(indol-3-yl)ethylamine 7, which is coupled with the 3-indolyl-alpha-oxoacetyl chloride 8 and subsequently used in a successful intramolecular Staudinger-aza Wittig cyclization to form the central dihydropyrazinone ring. The stereochemistry of naturally isolated hamacanthin B is revealed as the (S)-configuration.

Alkaloids↗

PubMed2002

Structure-based 3-D-QSAR analysis of marine indole alkaloids.

A 3-D-QSAR study has been performed on these indole alkaloid derivatives to correlate their chemical structures with their observed antitumor activity against IGROV1. Due to the absence of information on their active mechanism, comparative molecular field analysis (CoMFA) has been applied. A model able to well correlate the antitumor activity with the chemical structures of mono and bis(indole) alkaloids 1-18 has been developed which is potentially helpful in the design of novel and more potent antitumor agents.

Alkaloids↗