2045-25-2Relevant articles and documents
Metal free [4+1] and [5+1] annulation reactions to prepare heterocycles using DMF and its derivatives as one-carbon source
Liu, Lingfeng,Qiao, Chunhua,Shen, Bei,Xu, Yiwen
, (2020/04/01)
1,2,4-Triazolo[3,4-a]pyridines and related heterocycles and substituted triazines were commonly discovered scaffolds in a variety of pharmaceutical and agrochemical agents. Herein, we report a highly efficient and practical method using DMF and its derivative for the [4+1] and [5+1] annulation reactions to prepare these heterocycles. This metal free reaction takes advantages of shelf stable DMF as solvent and carbon donor, imidazole chloride as a catalyst, the mild reaction condition tolerates a broad substrate range and substitutes. The prepared 3-unsubstituted 1,2,4-triazolo[3,4-a]pyridine and derivatives allow further introduction of a variety of functional group1 at 3-position.
Regioselective synthesis of imidazo[1,2-a][1,3,5]triazines and 3,4-dihydroimidazo[1,2-a][1,3,5]triazines from [1,3,5]triazin-2,4-diamines
Dao, Pascal,Garbay, Christiane,Chen, Huixiong
, p. 3867 - 3871 (2013/07/05)
An efficient and practical procedure was developed to prepare novel imidazo[1,2-a][1,3,5]triazines and 3,4-dihydroimidazo[1,2-a][1,3,5]triazines with a good regioselectivity and high yields, starting from dicyandiamide and the corresponding arylamines. Mechanistic studies for the subsequent cyclocondensation with chloroacetaldehyde support a pathway, which begins with the displacement of the chloro atom activated by an adjacent CO group, followed by cyclization and dehydration.