Open-Air Dual-Diamination of Aromatic Aldehydes: Direct Synthesis of Azolo-Fused 1,3,5-Triazines Facilitated by Ammonium Iodide

Divergent synthesis of pyrrolidone fused pyrimido[1,2-b]indazole through selective trapping of an enone intermediate by 1H-indazol-3-amine

An oxidant-controlled divergent synthesis of a pyrrolidone fused pyrimido[1,2-b]indazole skeleton was developed through selective cyclization of an in situ generated enone intermediate and 1H-indazol-3-amine. The one-pot, metal-free process formed three C-N bonds, one C-C bond, and a tetrasubstituted carbon stereocenter containing a hydroxyl group. This method not only allowed for the synthesis of over 60 new pyrrolidone fused pyrimido[1,2-b]indazole derivatives, but was also compatible with the transformation of complex active molecules and the derivation of target products. Significantly, product 4q exhibited aggregation-induced emission (AIE) characteristics without any further modification.

Green Synthesis of Aromatic Nitrogen-Containing Heterocycles by Catalytic and Non-Traditional Activation Methods

Recent advances in the environmentally benign synthesis of aromatic N-heterocycles are reviewed, focusing primarily on the application of catalytic methods and non-traditional activation. This account features two main parts: the preparation of single ring N-heterocycles, and their condensed analogs. Both groups include compounds with one, two and more N-atoms. Due to the large number of protocols, this account focuses on providing representative examples to feature the available methods.

Di-tert-butyl peroxide as an effective two-carbon unit in oxidative radical cyclization toward 7-methylazolo[1,5-a]pyrimidines

An unexpected oxidative radical cyclization with DTBP as the C2 cyclic unit enables the assembly of privileged 7-methylazolo[1,5-a]pyrimidines.