A rapid metal-and additive-free room temperature method for C(sp 2 )-H thiocyanation of aminopyrazoles, aminoisoxazole, aminoisothiazole, amino uracils, and aliphatic enamines has been developed in an aqueous medium using hydrogen peroxide as a benign oxidant and ammonium thiocyanate as a thiocyanating agent. On the other hand, the reaction of hydrogen peroxide and ammonium thiocyanate followed by one-pot addition of NaOH provides the corresponding disulfides in the case of amino azoles, and pyrimidine-fused 2-amino thiazoles were observed in the case of aminouracils. The salient features of this method are the use of an eco-friendly oxidant, reaction tunability to access different products, wide substrate scope, and good to very good yields.

Herein, we report two novel methods for the synthesis of pyrimidine fused quinolines using a one-pot C-C and C-N bond forming strategy from the reaction of 6-aminouracils with 2-bromobenzaldehydes or 2-bromobenzyl bromide derivatives in the presence of 10 mol % CuCl without using any ligand. The reaction of 2-bromobenzaldehyde or its derivatives with 6-aminouracils in the presence of KCO as base and a catalytic amount of CuCl in DMF medium under microwave heating conditions provides corresponding pyrimidine fused quinoline derivatives in good yields within 30 min. Alternatively, pyrimidine fused quinoline derivatives have been synthesized from the reaction of 2-bromobenzyl bromides with 6-aminouracil derivatives in the presence of molecular oxygen, CuCl (10 mol %), and KCO as base in DMF under reflux conditions. Structures of all the products were unambiguously confirmed by spectroscopic techniques and by recording single crystal XRD of 3a.

A reaction medium dependent three-component reaction of isatin, 4-hydroxycoumarin and aminopyrazole/aminoisoxazole has been reported under microwave heating conditions for the synthesis of two different types of fused spirooxindoles.

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