A convenient route was successfully developed for the synthesis of novel heterocycles such as spiro-oxazino-quinoline derivatives from 2-aminoquinoline-3-carbonitrile (4) in good yield. The Spiro-quinoline derivatives (6, 8 and 10) were synthesized and further studied for their photophysical properties. Semiempirical molecular orbital calculation (PM3/PM6 for structure) proves to be a suitable tool for the prediction of absorption and fluorescence properties of these compounds.

Suzuki-Miyaura cross coupling was successfully used for C5-arylation in 4-amino-2-chloroquinoline-3-carbaldehyde using arylbornic acid and tetrakistriphenylphosphine palladium catalyst in water. Friedländer condensation reaction on 4-amino-2-chloro/2-arylquinoline-3-carbaldehyde and aromatic ketones gave novel aryl and diarylbenzo[h] [1, 6]naphthyridines in good yields. Fluorescence quantum yields were increased by introducing C2 and C5 π donor aryl benzo[h][1, 6]naphthyridines derivatives.

A series of 1,3,6-trisubstituted and 1,3,5,6-tetrasubstituted pyrazolo [3,4-b] pyridines 5 have been synthesized by series of reactions on 1-phenyl-3-carboxylate pyrazolone to obtain o-aminoaldehyde, which undergo facile condensation with various a-methylene ketones, nitriles, and esters, furnish fused pyridine derivative in good yield.

Novel 4‐amino‐6‐chloroquinoline‐3‐carbaldehyde has been synthesized by synchronous reduction by lithium aluminiumhydride and finally oxidation with MnO2. Friedländer condensation of it with reactive methylenes furnished novel benzo[3,4‐h][1,6]naphthyridine derivatives. J. Heterocyclic Chem., (2011).

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