SYNTHESIS OF SOME BIOLOGICALLY ACTIVE DERIVATIVES OF 2-HYDROXYMETHYL-5-HYDROXY -4H-PYRAN-4-0NE Miroslav VEVERKA a and Eva KRACOVICOVA h Q Institute of Biotechnology, Slovak Technical University, 81237 Bratislava and b Research Institute of Chemical Technology, 83603 Bratislava 833 Received April 24, 1989 Accepted August 24, 1989 Depending on reaction conditions, acylation of the phenolic and primary alcoholic group in l-hydro xymethyl-5-hydroxy-4H-pyran-4-one leads to mono- or disubstituted products. Also described is acylation of the phenolic group in 2-chloromethyl- or 2-bromomethyl-5-hydroxy-4H- -pyran -4-one as well as the nucleophilic replacement of the halogen by azide group. The prepared derivatives exhibit herbicidal and growth regulatory activity. One of the possible ways in the search for more selective and safer pesticides consists in preparation of modified traditional structures by partial synthesis from natural material. 2-Hydroxymethyl-5-hydroxy-4H-pyran-4-one (kojic acid) and its derivatives exhibit pesticidal activities 1 and they undergo an easy microbial degradation to nontoxic products 2 • In the present study we modified the phenolic and primary alcoholic group in 2-hydroxymethyl-5-hydroxy-4H-pyran-4-one and its derivatives by bonding to herbicidally active residues of carboxylic acids in order to improve transport properties of the desired structures in the plant system. Depending on the conditions, treatment of 2-hydroxymethyl-5-hydroxy-4H-pyran- -4-one with reactive derivatives of carboxylic acids affords monoacyl or diacyl derivatives. Reaction with benzoyl chloride or acetic anhydride in an excess of pyridine leads to acylation of both groupS3. Benzoylation in the presence of a small excess of aqueous alkali affords the 5-0-benzoyl derivative whereas with large excess of the alkali the reaction gives the 5,7-dibenzoyl derivative 3 . The 7-0-mono- acetate was prepared by treatment of the 5,7-0-diacetate with aluminium chloride 4 or by reaction with hydroxylamine hydrochloride in pyridine 3 • Benzoylation in the absence of a hydrogen chloride acceptor results in formation of the 5-0-benzoyl derivatives. Selective benzoylations are described by Poonia 6 • In our work, the phenolic group of the title compound and its 2-halogenomethyl and 2-azidomethyl derivatives was acylated with acyl chlorides in aqueous acetone in the presence of sodium hydroxide, or in acetone with triethylamine as the base (I-IV). The yields of these reactions are given in Table I. Further, we tried to prepare derivatives 1 -1 Vunder conditions described in the literatureS (in the absence Collect. Czech. Chem. Commun. (Vol. 55) (1990)