RESUMEN
The synthesis of a series of isoelectronic analogues of (S)-2-[3-(tert-butylamino)-2-hydroxypropoxy]-3-cyanopyridine (1) are described; included in this group are examples of thiazole, isothiazole, thiadiazole, pyrazine, and the structurally related naphthyridines. All of the compounds are similar to 1 in that they contain a cyano group ortho to the aminohydroxypropoxy side chain and meta to the nitrogen heteroatom. In addition, several related examples, having additional nuclear substituents and/or groups other than CN in the position adjacent to the aminohydroxypropoxy group, were prepared, and beta-adrenoceptor antagonist activity and vasodilating potency were determined. Three compounds, thiazole 2 and isothiazoles 3 and 27, effectively lowered mean arterial pressure in the SH rat at 5 mg/kg. Compounds 2, 3, and 27 increased iliac blood flow and exhibited beta-adrenergic blocking properties in the dog.
Asunto(s)
Antagonistas Adrenérgicos beta/síntesis química , Antihipertensivos/síntesis química , Piridinas , Animales , Presión Sanguínea/efectos de los fármacos , Perros , Femenino , Frecuencia Cardíaca/efectos de los fármacos , Hipertensión/fisiopatología , Isoproterenol/antagonistas & inhibidores , Masculino , Ratas , Flujo Sanguíneo Regional/efectos de los fármacos , Relación Estructura-Actividad , Vasodilatadores/síntesis químicaRESUMEN
Syntheses are reported for three metabolites (2-4) of timolol (1) formed by oxidative metabolism of the morpholine ring. GLC-MS comparisons are presented which establish that the two metabolites whose structures were previously in question are identical with their synthetic counterparts 2 and 3. In 2, metabolic oxidation of the 4-morpholinyl group of 1 had occurred at the carbon next to oxygen to give the 2-hydroxy-4-morpholinyl moiety, whereas in 3, the morpholine of 1 has been oxidized one step further and then ring opened to produce the N-(2-hydroxyethyl)glycine substituent. Biological testing of synthetic samples of the three major metabolites from human urine (3, 4, and 6) indicated that only 4, in which the morpholine moiety has been degraded to a 2-hydroxyethylamino group, had significant beta-adrenergic blocking activity (one-seventh that of timolol in anesthetized dogs).