Studies on Isomeric Pyridylisoxazoles

Abstract

Atstracz-Data concerning the reaction between hydroxylamne hydrochlarrde and 1-(2-pyrldylI-3-phenyl-(1 a1 and I-12-thlenyll-3-phenyl-1.3-propane- d m n e (I 1) disagree n t h those prevrausly reported m ilrerature.The same reactlo" was also studred cmp1oyrng a series of 1.3-diketones-The dlrecrlon of enollzatlon of 1.3-dlketanes accounted far the lsomerrc lsoxazoles formation.1 It was reported that 1.3-dlkctonesI a and I 1 r e a c t with hydroxylarnine hydrochloride to glve as the sole products i-phunyl-3-(2-pyrldyl)-(IT a! and 3-phenyl-5-~2-thlenylI-~soxazo1e ( 1 1 1 I1 2 reipect~vely .lnstead a careful enanrnarion of these reacrlons showed that n mlxture of t w o lsomeri was always formed.These results together with the p h a r m a c e u i l c a l rnierest of isoxar01e 5 W r l d r n r m s a ~t s ~, ~ stimulated to extend m e same r e a c t L o n to 1,3-d1ketones I b-1 .~i the same i m e the combmed substxtnent effects an the formarron of isomeric isoxaro~rs I I and 111 can he studled.The hltherto unknown diketone2 were prepared by standard procrdorcs.The lsaxarolepyrldln~um salts resulting from the cycllraiion r c a c t r o n of I a-i were converted to free bases With sodrum carbanate.