Research For The Synthesis And Biological Activities Of Aminotriazolethione Schiff Bases

Triazole compounds and its derivatives exhibit excellent biological activities. They have been widely used in pesticide and medicine due to their high efficiency, low toxicity and inward absorbent features. In order to search for new fungicides with broad spectrum and high activity and to explore the relationship between their structures and biological activities, thirty Schiff base compounds were synthesized and their structures were confirmed on the basis of IR, ~1H NMR and elemental analysis. The preliminary bioassay indicated that the title compounds showed good fungicidal activities to test vegetable pathogens. The relationship between the structures and the fungicidal activities of the compounds has been discussed.Part one: 1, 3-diaminothiourea was synthesized using hydrazine hydrate and carbon disulfide as start materials. Then 5-alkyl-4-amino-2, 4-dihydro-1, 2, 4-triazole -3-thione were prepared by 1,3- diaminothiourea reacting with acetic acid, propionic acid, butanoic acid, isobutyric acid respectively. Twenty-four Schiff bases were synthesized by 5-alkyl-4-amino-2, 4-dihydro-1, 2, 4-triazole-3-thione and aromatic aldehydes. Their structures have been confirmed by ~1H NMR, IR and elemental analysis. The preliminary biological activities have been tested. The results showed that most of them exhibited excellent fungicidal activities. The relationship between the structures and the biological activities has been discussed.Part two: 4-amino-5-(4-pyridyl)-2, 4-dihydro-1, 2, 4-triazole-3-thione was prepared using isoniazid, carbon disulfide and hydrazine hydrate as start materials. Then six Schiff bases were synthesized by 4-amino-5-(4-pyridyl)-2, 4-dihydro-1, 2, 4-triazole-3-thione and aromatic aldehydes. Their structures have been confirmed by ~1H NMR, IR and elemental analysis. The preliminary bioassay indicated that the title compounds showed good fungicidal activities to five vegetable pathogens. The relationship between the structures and the fungicidal activities of the compounds has been discussed.