Synthesis Of Novel Chromeno[3,2-e][1,2,4]triazolo[1,5-c] Pyrimidinone Derivatives

The 1,2,4-triazole compounds with 6π electron conjugated system can form carbene structure, which make them have strong coordination ability, easy to form hydrogen bonds, π-π stacking, and thus have good prospects in medicine, pesticides, physics, materials science, life science and other research fields. Due to chromeno[3,2-e][1,2,4]triazole [1,5-c]pyrimidine derivatives not only possess the structure of chromeno, but also contain triazolepyrimidone ring, they have valuable pharmacological properties such as antibacterial, anti-cancer, anti-tumor, weeding and bactericidal. Additionally, a carbonyl group was added into the cyclohexanone ring of chromeno[3,2-e][1,2,4]triazole[1,5-c]pyrimidine via chemical structural modifications, which increased its activity.Firstly, 2-amino-3-carbonitrile-chromene derivatives 2 were prepared by the reaction of cyclohexane-1,3-dione with 2-arylylidene malononitrile derivatives in ethanol via Michael reaction in this article. Compounds 2 and excess triethyl orthoformate were combined and heated under refluxing to give eight novel intermediates ethyl formimidate derivatives 3. And then, 99 % hydrazine monohydrate was added dropwise to the derivatives 3 in ethanol, and the solution was stirred at-5 ℃. The precipitate was separated to afford nine novel 3-amino-4-imino-5-aryl-5,7,8,9-tetrahydro-3H-chromeno[2,3-d]pyrimidin-6(4H)-one derivatives 4. Finally, twenty-one novel chromeno[3,2-e][1,2,4]triazolo[1,5-c]pyrimidin-11(10H)-one derivatives 5, 6 and 7 were synthesized respectively by the reaction of 4 with excess triethyl orthoformate(formic acid), acetic anhydride or ethyl cyanoacetate. The synthetic route for the target compounds is commonly used materials as solvent, and has the advantages of simple operation, mild reaction conditions and highly yield.In this paper, forty compounds containing heterocyclic ring were synthesized, and characterized by IR, 1H NMR, MS. Moreover, the single crystals of 5d, 5f, 5g, 6b, 6c, 6d, 6e, 6f and 7f were obtained and determined by X-ray diffraction analysis. Most of these compounds are all crystallized in space group p-1 in room temperature, which may have structure of SHG.