Studies in Heterocyclic Comopunds of Expected physiological Activities

Compounds containing a chromone or a furochromone moiety may have a variety of biological effects, especially antispasmodic activity. Searching for the development of novel heterocyclic antispasmodic agents that possess potent activity and small toxicity led the authors to prepare different fourchromones and chromones aiming to use them as antispasmodic and bronchodilator agents.1) Angular furochromones :These derivatives were obtained through the oxidation of visnagin with potassium dichromate and sulphuric acid to produce 6-formyl-7-hydroxy-5-methoxy-2-methylechromone (I), the reduction of which leads to the 7-hydroxy-5-methoxy-2, 6-dimethylchromone (II). The later compound is the key intermediate for three routes of syntheses of angular furochromones and also used for preparing a group of amino acid esters. The first route is the condensation of (III) with different -bromacetophenones followed by cyclization with sodium ethoxide in absolute ethanol to give 5-methyoxy-2, 6-dimethyl-9-substituted-4H-furo [2, 3-h]-1-benzopyran-4-one (IV).2) Chromone derivatives :6-Formyl-7-hydroxy-5-methoxy-2-methylchromone (I) is the key intermediate for the synthesis of different series of chromone derivatives.The first is the formation of 8-arylazo-compounds (XIII) by coupling with diazonium salts. A group of hydrazones are also prepared by reaction of phenyl hydrazine, 1.N.H. and phenylthiosemicarbazide with (I) to produce compounds (XIVa-d) and (XVa, b). ethers XVIIIf-h & XIXa-c) of the last two compounds (XVa, b). were also prepared. Anils were obtained by the reaction of (I) with aniline and p-amino salicylic acid affording (XVII & XVa). Condensation of (I) with alkyl halides or -bromoacetophenones gave a group of 7-alkoxy and acyloxy derivatives (XVIa-f).