Biomedical subjects
Publications and source records attributed to Yan-Guang Wang.
Aromatic aldehydes reacted with anilines and benzenediazonium-2-carboxylate to afford 6-aryl-phenanthridines. The reaction furnishes a rapid and direct construction of substituted phenanthridine rings from readily available starting materials via a one-pot cascade process.
A variety of substituted iminocoumarins are prepared in good to excellent yields via a copper-catalyzed multicomponenet reaction of sulfonyl azides, terminal alkynes, and salicylaldehydes or o-hydroxylacetophenones. The method is general, mild, versatile, and efficient. A plausible mechanism for the domino process is proposed.
A benzyl-protected analog of the phenylpropanoid glycoside arenarioside, (4-benzyloxyphenyl)ethyl alpha-L-rhamnopyranosyl-(1-->3)-4-O-[(E)-3,4-di-O-benzyl-caffeoyl]-[beta-D-xylopyranosyl-(1-->6)]-beta-D-glucopyranoside (22), was synthesized through two different routes from D-glucose. This is the first approach on the synthesis of a trisaccharide phenylpropanoid glycoside, although the benzyl-protecting group in the backbone of the arenarioside analog could not be removed by conventional debenzylation procedures.
[reaction: see text] A new triethylamine-catalyzed cascade reaction of aromatic aldehydes with propiolates has been developed. This serial multi-bond-forming process furnishes diverse polycyclic aromatic hydrocarbons, including naphthalenes, phenanthrenes, benzofurans, and 2,3,9,9a-tetrahydronaphtha[2,3-b]furans. The chemical outcome of the process depends on the reaction temperature and can be tailored selectively by an appropriate choice of experimental conditions.
[reaction: see text] A facile parallel synthesis of polysubstituted 2,6-dicyanoanilines via microwave-promoted three-component reaction of aldehydes, ketones, and propanedinitrile in solution and also on polymer support has been developed. The screening for optical properties identified two new compounds with high fluorescence quantum yields.
[reaction: see text] Aryl triflates are effectively converted to the corresponding anilines under microwave irradiation in 1-methyl-2-pyridone (NMP) without base and catalyst. Aryl triflates substituted with both electron-poor and electron-rich groups give good to excellent yields. It is noteworthy that the halogenated aryl triflates can chemoselectively react with amines to afford halogenated anilines.
7-Arylseleno-7-deoxydaunomycinone derivatives 3a-e and 7-thiophenyl-7-deoxydaunomycinones (7 and 8) were synthesized and the antitumor activities of them were evaluated against human stomach cancer SGC-7901 and human leukaemia HL60. The cytotoxic assay show that seleno daunomycinone derivatives are much better inhibitory activity than thiodaunomycinone and the structure-activity relationship was discussed. 7-Deoxydaunomycinone 4 was obtained when selenophenols were used in excess and the possible mechanism was proposed.
Twelve new 4beta-halogenated benzoylamino compounds (7.1-7.12) of podophyllotoxin have been synthesized, and their structures were confirmed by IR, 1H-NMR, MS spectra as well as CHN elemental analysis. These compounds showed delayed insecticidal activity against 5th instar larvae of Pieris rapae Linnaeus in vivo, when tested by a leaf-dipping method at a concentration of 250ppm. By preliminary qualitative structure-activity relationship analysis, we found the following results: 1) Compounds 7.2, 7.5-7.9 were more potent than the nature parent product in the mortality after 15 d against P. rapae in vivo. Especially compounds 7.5 and 7.6 bearing meta- and para-chlorobenzene substituents respectively, were the most potent of these compounds; 2) Substitution on the benzene ring moiety of 4beta-benzoylamino podophyllotoxin (PPT) with Cl, Br, I at the para or at the meta position yielded compounds which were as potent or more potent than those containing the corresponding substituting group at the ortho position. 3) Substitution on the benzene ring moiety of 4beta-benzoylamino podophyllotoxin with I either at the ortho, meta or para position yielded less potent compounds (7.10-7.12) when compared with PPT.
The present situation of the HIV/AIDS epidemic is very grim in China. The probability of China becoming a country with a high prevalence of HIV/AIDS cannot be excluded because there have been factors which promote the wide spread of HIV if we fail to take timely action to prevent it at the opportune moment. However, China's HIV prevention policy is inadequate. Health professionals and programmers believed that they could take a conventional public health approach to cope with the HIV epidemic. They simply ignored the fact that HIV infection is an epidemic so special that their approach is not effective to deter the epidemic. Many health professionals and programmers bypassed ethical issues that had emerged in the prevention of the HIV epidemic. Even some health educators, sexologists and officials believe that 'AIDS is the punishment for promiscuity', and this belief has led to discrimination and stigmatization of AIDS patients, HIV positive people, their family members and high risk groups. Although homosexuality is not illegal, the police can always find any reason to detain homosexuals. A difficult ethical issue is about the laws prohibiting prostitution and drug use in China which force prostitutes and intravenous drug users underground, giving them no chance to access information, education and the services needed to protect them. The dilemma facing China is whether to stay with a restrictive policy for the reason of ideology cleansing or to turn to a more supportive policy. It is necessary to have some change in the ethical framework to evaluate the action in HIV prevention. Tolerance should be the first ethical principle.