ABSTRACT
Continuing a targeted search for new leading structures with diuretic action among tricyclic derivatives of hydroxyquinolines, which are of interest as potential inhibitors of aldosterone synthase, the synthesis of a series of the corresponding pyrido[3,2,1-ij]quinoline-6-carboxanilides was carried out by amidation of ethyl-7-hydroxy-5-oxo-2,3-dihydro-1H,5H-pyrido[3,2,1-ij]quinoline-6-carboxylate with aniline, aminophenols and O-alkylsubstituted analogs with high yields and purity. The optimal conditions of this reaction are proposed; they make it possible to prevent partial destruction of the original heterocyclic ester and thereby avoid formation of specific impurities of 7-hydroxy-2,3-dihydro-1H,5H-pyrido[3,2,1-ij]quinolin-5-one. To confirm the structure of all substances obtained, elemental analysis, nuclear magnetic resonance (NMR) spectroscopy, and mass spectrometry were used. Moreover, the peculiarities of their ¹H and 13C-NMR spectra, as well as their mass spectrometric behavior under conditions of electron impact ionization, were discussed. The effect of pyrido[3,2,1-ij]quinoline-6-carboxanilides on the urinary function of the kidneys was studied in white rats of both genders by the standard method of oral administration at a dose of 10 mg/kg. Testing was conducted in comparison with hydrochlorothiazide, as well as with structurally close pyrrolo[3,2,1-ij] quinoline-5-carboxanilides studied earlier with the same substituents in the anilide fragments. It was found that addition of one methylene unit to the heterocycle partially hydrogenated and annelated with the quinolone core has a positive impact on biological properties-most of the substances studied exhibit a statistically significant diuretic effect exceeding the activity of not only hydrochlorothiazide, in some cases, but also the action of the structural analogs. The important structural and biological regularities, which are common with pyrroloquinolines and introduced by a chemical modification, were revealed. The importance of the presence in the structure of terminal amide fragments of tricyclic quinoline-3-carboxamides of a 4-methoxy-substituted aromatic ring was particularly marked. The expediency of further study of pyridoquinolines as promising diuretic agents has been shown.
ABSTRACT
In continuing the search for new analgesics among derivatives of 2,1-benzothiazines, a series of corresponding toluidides and xylidides of 4-hydroxy-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylic acid has been synthesized by the reaction of ethyl 4-hydroxy-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylate with equimolar amounts of mono- and dimethyl-substituted anilides in boiling dry xylene. Their structure has been confirmed by the data of elemental analysis, nuclear magnetic resonance (NMR) spectroscopy (¹Ð and 13С), as well as mass spectrometry. All compounds obtained were subjected to pharmacological screening to identify their analgesic properties. Testing was carried out in male rats using the standard model of the thermal tail-flick (tail immersion test) in parallel and in comparison with the structurally related drugs meloxicam and piroxicam. Among the substances studied, highly active oral painkillers have been found; they exceed the analgesic effect of the reference drugs using the same dose. Interesting structural and biological regularities have been described; they will be useful in further research on creating promising new analgesics based on 4-hydroxy-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxamides.
ABSTRACT
In the title compound, C(14)H(15)NO(4), the bicyclic fragment and the ester group form a dihedral angle of 86.7â (2)°. Inter-molecular O-Hâ¯O and C-Hâ¯O hydrogen bonding connects mol-ecules into a helix along the crystallographic b axis.
ABSTRACT
In the title compound, C(18)H(21)BrN(2)O(5), conjugation between the π-donating N-C-O fragment and the π-withdrawing carbonyl group results in considerable redistribution of the electron density within the dihydropyridinol ring. This effect is also promoted by the formation of an intra-molecular N-Hâ¯O hydrogen bond. The five-membered heterocycle is disordered over two envelope conformations in a 0.35:0.65 ratio.
