Categories: Synthesis of N-Heterocycles >
Synthesis of 1,3,5-triazines
A simple and efficient method for the base-mediated synthesis of unsymmetrical 1,3,5-triazin-2-amines uses readily available imidates, guanidines, and amides or aldehydes as the starting materials and cesium carbonate as the base. This three-component reaction provides diverse 1,3,5-triazin-2-amines in good yields with tolerance of a broad range of functional groups.
L. Pan, Z. Li, T. Ding, X. Fang, W. Zhang, H. Xu, Y. Xu, J. Org. Chem., 2017, 82, 10043-10050.
A series of primary alcohols and aldehydes were treated with iodine in ammonia water under microwave irradiation to give the intermediate nitriles, which without isolation underwent [2 + 3] cycloadditions with dicyandiamide and sodium azide to afford the corresponding triazines and tetrazoles in high yields.
J.-J. Shie, J.-M. Fang, J. Org. Chem., 2007, 72, 3141-3144.
Activated carboxylic acids react with a stoichiometric amount of zinc dimethyl imidodicarbonimidate in CH2Cl2-pyridine with molecular sieves to form 4,6-dimethoxy-1,3,5-triazines in high yields.
S. Oudir, B. Rigo, J.-P. Hénichart, P. Gautret, Synthesis, 2006, 2845-2848.
An efficient copper-catalyzed reaction of 1,1-dibromoalkenes and biguanides provides substituted 2,4-diamino-1,3,5-triazines under mild conditions in good yields. The reaction tolerated alkyl-, heterocyclic-, or aryl-substituted 1,1-dibromoalkenes containing functionalities such as nitriles, ethers, and halogens.
C. Zhang, M.-T. Ban, K. Zhu, L.-Y. Zhang, Z.-Y. Luo, S.-N. Guo, D.-M. Cui, Y. Zhang, Org. Lett., 2017, 19, 3947-3949.