No abstract

Flavone (1) was found to protect against ethanol-induced gastric damage in rats; however, it is known that certain compounds in the flavone class, including flavone itself, are inducers of hepatic drug metabolizing enzymes. With the hope of identifying gastroprotective flavones that have minimal effects on drug metabolizing enzymes, we have synthesized and evaluated selected flavone analogs. Gastroprotective potency in the ethanol model was retained by methoxy substitution in the 5-position (4) and by methoxy (12) or methyl (14) substitution in the 7-position. A number of substituted analogs of the potent molecule 5-methoxyflavone (4) were also synthesized, and in many cases, these substitutions provided gastroprotective molecules. In order to assess liver enzyme induction potential, two of the gastroprotective flavones, 7-methoxyflavone (12) and 5-methoxy-4'-fluoroflavone (26), were examined for their effect on liver microsomal cytochrome P450 and 7-ethoxyresorufin O-dealkylase (CYP1A) activity. These two compounds caused minimal changes in the cytochrome P450 concentration and were considerably less potent than beta-naphthoflavone as inducers of CYP1A enzyme activity. Furthermore, following oral administration to rats, 5-methoxy-4'-fluoroflavone (26) was found to protect against indomethacin-induced gastric damage. These results indicate that, through appropriate substitution, flavones can be obtained that are gastroprotective but have minimal effects on drug-metabolizing enzymes.

organic chemistry, review organic chemistry, review Z 0200 25 -357 Gastroprotective Agents for the Prevention of NSAID-Induced Gastropathy -[e.g. ebrotidine, quercetin, somatostatin, cisapride, ecabet sodium, xanthine A-906119; 173 refs.]. -(ARES, J. J.; OUTT, P. E.; Curr.

No abstract

A general synthesis of 4-substituted 6-(2-imidazolinylamino)-5,8-dimethylquinolines 1 has been developed. All new compounds were synthesized from a common intermediate, 5,8-dimethyl-6-nitro-4-quinolone 3, the structure of which was confirmed by X-ray crystallography. This methodology involved the conversion of 3 into either a 4-chloro- or 4-bromoquinoline followed by the introduction of various 4-substituents late in the synthetic sequence. Substituents introduced in this way include alkyl (18a), alkoxy (12a, 12b), halo (9, 12c, 16), cyano (18b), thioalkyl (12d), acetamido (14), carboxamido (19), and hydroxy (10). This work illustrates the utility of 4-haloquinoline intermediates in the general synthesis of 4-substituted quinolines.