UDC 547.814.5 7-Hydroxy-3-phenoxy-8-formylchromones were synthesized using the Duff reaction and were reacted with 2,4-dinitrophenylhydrazine to produce hydrazones and with an excess of hydrazine hydrate to produce the pyrazole recyclization products. Derivatives of α-pyrono[2,3-f]chromones were synthesized using the Knoevenagel condensation with 2-azahetarylacetonitriles and the Perkin reaction.Few 7-hydroxy-8-formylchromones (isounonal 1) and their partially hydrogenated derivatives, lavinal (2), and 4,7-dihydroxy-6-methyl-5-methoxy-8-formylflavan (3) have been discovered within the broad class of natural flavonoids. The first two occur together in plants of the family Annonaceae [1-6] such as Dasymaschalon rostratum [1], Desmos chinensis Lour [2], Desmos cochinchinensis [3], and Unona lawii Hook. f. & Thoms [4]. The last is found in roots of Desmos cochinchinensis [3]. A mixture of all three flavonoids isolated from D. cochinchinensis [3] exhibited antimalarial activity whereas lavinal itself was viewed as a potential AIDS agent [7]. Phenoxychromones are also found in nature [8]. This enabled us to combine these two classes into one in order to study properties different from those of each class individually but characteristic of the system as a whole.The classical method for synthesizing 7-hydroxy-8-formylchromones is the Duff reaction [9-15]. Starting 7-hydroxy-3-phenoxy-8-formylchromones 4-10 were synthesized using the Duff reaction by heating chromones 11-17 with urotropine in acetic acid with subsequent work up of the reaction mixture by HCl solution. PMR spectra of these compounds in DMSO-d 6 showed a singlet for the formyl group near 10.5 ppm and a broad singlet for the hydroxyl proton that was shifted to weak field relative to the resonance of the hydroxyl in the starting chromone by 1.6-1.7 ppm as a result of the formation of an intramolecular H-bond.The presence of the formyl group was also confirmed by formation of the 2,4-dinitrophenylhydrazone 18 upon reaction of 8 with 2,4-dinitrophenylhydrazine. The PMR spectrum of 18 exhibited resonances for aromatic protons characteristic of starting chromone 8; 1H doublets for H-5′′ and H-6′′ at 8.39 and 7.89 ppm, respectively; and a singlet for H-3′′ of the 2,4-dinitrophenyl group at 8.90 ppm.The reaction of 8-formylchromone 6 with an excess of hydrazine hydrate did not stop at the formation of the hydrazone but led to recyclization of theγ-pyrone ring to form pyrazole 19. This was confirmed by a broad singlet typical of the pyrazole NH proton at 12.90 ppm, singlets for two hydroxyls at 11.78 and 12.07, and a 2H singlet at 6.69 for the hydrazone amino group in the PMR spectrum recorded in DMSO-d 6 .

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