Keywords: alkylamides, 4-hydroxy-2-oxoquinoline-3-carboxylic acids, diuretic activity, anti-inflammatory activity, X-ray structural analysis.For transformation of ethyl 1-hydroxy-3-oxo-5,6-dihydro-3H-pyrrolo[3,2,1-ij]quinoline-2-carboxylates (1) to alkyl-, aryl-, or hetarylamides (of interest as potentially biologically active materials) it was proposed to treat them with a 40% excess of the corresponding amine in refluxing bromobenzene over 20 h with subsequent distillation of solvent at reduced pressure and purification of the final reaction products [2]. At the same time, the high reactivity of 1-R-3-ethoxycarbonyl-4-hydroxy-2-oxo-1,2-dihydroquinolines has been noted and this allows them to be amidated quite efficiently [3][4][5]. The obvious structural similarity of ester 1 with these compounds led us to suggest that they will react with amines (at least aliphatic) under milder conditions.i R = C 5 H 11 , j R = i-C 5 H 11 , k R = 2-hydroxyethyl, l R = 3-hydroxypropyl, m R = cyclo-C 3 H 5 ,

Keywords: amides, 2-hydroxy-4-oxo-4H-pyrido-[1,2-a]pyrimidine-3-carboxylic acids, tricarbonylmethane heterocyclic derivatives, diuretic activity, X-ray structural analysis.The problem of discovering novel classes of chemical substances capable of diuretic action, and particularly important, those which are highly efficient and safe diuretic medicines has not lost its urgency even over recent decades. Interesting substances investigated within this scheme are amidated 4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acids derivatives [2,3]. Although for a long time high diuretic activity has not been considered a characteristic of quinolone compounds, several of these materials proved extremely promising and have been subjected to broad pharmacological investigation to this time. With this in mind we have carried out the synthesis and biological screening to reveal the ability of the series of structurally related 2-hydroxy-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carboxylic acid N-R-amides 1-3 to increase the diuretic kidney function.It was found that the alkylamides 1a-u (Table 1) can be prepared by the reaction of ethyl 2-hydroxy-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carboxylate (4) with a two, or better three, fold excess of the corresponding alkylamine in refluxing ethanol. It was initially proposed that it was necessary to use quite a large excess of the _______ * For Communication 143 see [1].

acid anilides has been carried out. The antitubercular activity and the effect on the urinary function of the kidney have been studied for the compounds prepared. A structure-biological activity relationship is discussed.In recent times the attention of synthetic chemists has been drawn to a search for biologically active substances in order to create from them novel medicinal compounds and it has been ever more attracted to 4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acid anilides [2][3][4][5][6][7][8]. This is explained not only by the broad spectrum of pharmaceutical activity of the studied 4-hydroxyquinol-2-ones and their natural occurrence but also by the ready chemical modification of their basic structure. Directed changes can be introduced into any part of the basic molecule by quite simple methods guaranteeing the best access to an almost unlimited range of analogs which, in turn, significantly increases the likelihood of discovering promising structural leads in subsequent study.Condensation of primary aromatic amines with triethyl methanetricarboxylate in conventional conditions gives primarily the methanetricarboxylic acid trianilides. During microwave irradiation the reaction given occurs somewhat differently and indeed yields 4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acid anilides [7]. To some extent, the low yields are compensated by the synthesis of the target compounds in a single stage. This method is certainly of interest although the promising application of it is small since both the quinolone ring and the anilide fragment are formed from the same aniline.

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The interaction of 4-methyl-2-oxo-1,2-dihydroquinoline-3-carboxylic acid with thionyl chloride in oxygen-containing solvents leads to the formation of a significant amount of colored side products, consequently it was proposed the reaction be carried out in carbon tetrachloride. The synthesis of a series of amides was effected by the amidation of the obtained acid chloride with appropriate primary arylalkylamines. Results are presented of a study of the effect of the synthesized compounds on the urineexcreting function of the kidney.