Li-Xue Zhang

Synthesis and Biological Activity of 3-(2-Furanyl)-6-Aryl-1,2,4-Triazolo[3,4-b]-1,3,4 –Thiadiazoles

3-(2-Furanyl)-4-amino-5-mercapto-1,2,4-triazole (1) was prepared from 2-furoic acid through a multi-step reaction sequence. Compound 1 reacted with aromatic acids in the presence of phosphorus oxychloride to give 3-(2-furanyl)-6-aryl-1,2,4- triazolo[3,4-b]-1,3,4-thiadiazoles (2). The structures of all the newly synthesized compounds have been confirmed by elemental analysis, IR, 1H-NMR, 13C-NMR and mass spectra. The bioassay indicated most of the title compounds possess significant growth promoting effects on mung bean radicles.

Synthesis and Biological Activity of Some Novel Derivatives of 4-Amino-3-(D-galactopentitol-1-yl)-5-mercapto-1,2,4-triazole

To discover new 1,2,4-triazole derivatives which may possess significant biological activities, we synthesized a series of novel 6-aryl-3-(D-galactopentitol-1-yl)-7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines and 4-(arylmethylidene)amino-5-(D-galactopentitol-1-yl)-3-mercapto-4H-1,2,4-triazoles from 4-amino-3-(D-galactopentitol-1-yl)-5-mercapto-1,2,4-triazole. All the title compounds were characterized by elemental analysis, IR, 1H- and 13C-NMR. Plant growth-regulating activity tests showed that these compounds have remarkable effects on the growth of radish and wheat.

Chemical composition of the green alga Codium Divaricatum Holmes

A new sterol, 24-R-stigmasta-4,25-diene-3β,6β-diol (1), along with three known compounds (2-3), was isolated from the green alga Codium divaricatum Holmes, a traditional Chinese medicine, which is efficacious against cancer. All structures were determined by spectroscopic methods and comparison with related known compounds. Single-crystal X-ray crystallography allowed us to confirm the structure of 1. To our knowledge, the compound 1 is reported as the first from natural source, and compounds 2, 4 have not been isolated from green algae before.

Synthesis and Biological Evaluation of Some Novel Schiff’s Bases from 1,2,4-Triazole

We have synthesized a number of novel Schiffs bases from 4-amino-3-(D-glucoheptonic-hexitol-1-yl)-1H-1,2,4-triazole-5-thione. By attaching D-glucoheptonic-hexitol-1-yl residues to 1,2,4-triazole at the 3-position, the solubility of the title compounds has been improved greatly. All the products have been characterized by elemental analysis, IR, 1H-NMR, 13C-NMR and MS. The plant-growth regulating effects of the title compounds were examined. From the biological activity results, we found that most compounds showed weak to moderate activities.

Regioselective Synthesis of 1-(2,6-Dichloro-4-Trifluoromethylphenyl)- 4-Alkyl-1H-[1,2,3]-Triazoles

A new and efficient method for the synthesis of 1-(2,6-dichloro-4-trifluoro-methylphenyl)-4-alkyl-1H-[1,2,3]-triazoles by the room temperature 1,3-dipolar cycloaddition of (2-azido-1,3-dichloro-5-trifluoromethyl)benzene with terminal alkynes in the presence of Cu (I) salt as catalyst is reported. All the reactions gave 1,4-disubstituted products with high regioselectivity, as no 1,5-disubstituted product was formed. The structures of all the title compounds have been confirmed by elemental analysis, 1H- and 13C-NMR and in addition, the structure of compound 5a was investigated by X-ray crystallography.

Syntheses and Biological Activities of 6-Aryl-3-(3-hydroxy- propyl)-7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines

A series of 6-aryl-3-(3-hydroxypropyl)-7H-1,2,4-triazolo[3,4-b][1,3,4]-thiadiazines were synthesized by the reaction of 4-amino-3-(3-hydroxypropyl)-5-mercapto-1,2,4-triazole (1) with substituted omega-haloacetophenones. Their structures were confirmed by elemental analysis, IR, 1H-NMR, and 13C-NMR. Tests of plant growth regulating effects showed that the title compounds display remarkable inhibitory activities on the growth of radish and wheat.

Synthesis and Biological Activities of Some Novel Triazolothiadiazines and Schiff Bases Derived from 1,2,4-Triazole

3-substituted-4-amino-5-mercapto-1,2,4-triazoles are versatile compounds for constructing various biologically active heterocycles. To find more 1,2,4-triazole derivatives that may possess significant biological activities, we synthesized a number of novel 3-(4-ethoxyphenyl)-6-aryl-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines and 4-(arylmethylidene)amino-5-(4-ethoxyphenyl)-3-mercapto-4H-1,2,4-triazoles. All the title compounds were characterized by elemental analysis and NMR data, and the compound 5f was investigated with X-ray crystallography (CCDC No. 611639). The plant-growth regulating effects of those Schiff bases were examined, and they showed an inhibiting effect on the growth of wheat radicles and radish radicles.

Simple and convenient synthesis of 1,3,5-triarylbenzenes from ketones

A new and efficient synthesis of a series of 1,3,5-triarylbenzenes was accomplished in good yields via the triple condensation of aryl methyl ketones promoted by thionyl chloride in anhydrous ethanol. The method is simple and convenient.

4-Amino-3-(1,2,3,4,5-penta­hydroxy­pentyl)-1,2,4-1H-triazole-5(4H)-thione

In the title compound, C7H14N4O5S, the 5-mercapto substituent of the 1,2,4-triazole exists in the thione form [C=S = 1.666 (5) A], with the protonated N atom of the triazolyl ring, the amine group and the hydroxy groups of the pentyl chain engaged in extensive hydrogen-bonding interactions, giving rise to a three-dimensional network structure.

Synthesis and Biological Activities of Some Novel Triazolothiadiazines and Schiff Bases Derived from 4-Amino-3-(4-hydroxyphenyl)-1H-1,2,4-triazole-5(4H)-thione

A series of novel 4-(6-substituted-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-3-yl)phenols (5a–5n) and (E)-4-substituted-3-(4-hydroxyphenyl)-1H-1,2,4-triazole-5(4H)-thiones (6a– 6h) has been synthesized in high yields. The structures of all the title compounds have been determined by elemental analysis, IR, MS, 1H NMR, and 13C NMR, and the compound 5a was investigated with X-ray crystallography (CCDC No. 666889). Most of the title compounds possessed high plant growth–regulating activities. Supplemental materials are available for this article. Go to the publishers online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.