ABSTRACT A straightforward and efficient multicomponent strategy has been developed for the synthesis of fused heterocyclic Schiff base derivatives featuring chromene and pyrano2,3‐ d pyrimidine frameworks. Utilizing a catalytic amount of sulfamic acid, the reaction proceeds under reflux through the condensation of cyclic diketones, malononitrile, and benzaldehyde. Subsequent Schiff base formation with aromatic aldehydes yields good amounts of structurally diverse hybrid molecules. This metal‐free protocol involves sequential C─C and C─N bond formations, demonstrating broad substrate tolerance. Key advantages include the recyclability of the catalyst, mild reaction conditions, minimal purification requirements, and operational simplicity. The approach provides rapid access to bioactive scaffolds with pharmacologically significant fused ring systems. Preliminary antimicrobial evaluations of the synthesized compounds revealed promising activity, highlighting their potential as therapeutic candidates. Overall, this methodology offers a sustainable and scalable route for constructing medicinally valuable heterocyclic architectures.
Bhatnagar et al. (Sun,) studied this question.