Novel annulated chromeno[3',2':5,6]pyrido[2,3-d][1,3,4]thiadiazolo[3,2-a] pyrimidines and chromeno[3'',2'':5',6']pyrido[2',3':4,5]pyrimido[2,1-b][1,3,4] thiadiazines: Synthetic approaches and antimicrobial efficiency

The current study includes synthetic approaches for some linear heterocyclic compounds containing chromone moiety. Chromenopyridopyrimidine bearing amino-thione functions 4 was efficiently synthesized starting from 6,8-dimethylchromone-3-carbonitrile (1). The novel chromenopyridothiadiazolopyrimidines were synthesized through condensation of the key precursor 4 with some mono-electrophilic reagents. In addition, heteroannulated chromenopyridopyrimidothiadiazines were synthesized through condensation of compound 4 with some α-halogenated carbonyl reagents. The synthesized products were examined for their antimicrobial efficiency appearing remarkable activity against the inspected microorganisms especially compounds 7, 12 and 14. The synthesized products were inferred using analytical and spectral data.