85903-35-1Relevant academic research and scientific papers
Cyclocondensation of hydroxylamine with 1,3-bis(het)arylmonothio 1,3-diketones and 1,3-bis(het)aryl-3-(methylthio)-2-propenones: Synthesis of 3,5-bis(het)arylisoxazoles with complementary regioselectivity
Raghava, Byregowda,Parameshwarappa, Gangajji,Acharya, Anand,Swaroop, Toreshettahally R.,Rangappa, Kanchugarakoppal S.,Ila, Hiriyakkanavar
, p. 1882 - 1892 (2014/04/03)
Efficient routes for the regioselective synthesis of 3,5-bis(het) arylisoxazoles with complementary regioselectivity have been developed. The methods involve the cyclocondensation of hydroxylamine hydrochloride with either 1,3-bis(het)aryl-monothio-substituted 1,3-diketones 1 or with 3-methylthio-1,3-bis(het)aryl-2-propenones 2 under various reaction conditions. In the first protocol, diketones 1 were treated with hydroxylamine hydrochloride in the presence of sodium acetate/acetic acid (pH 2.2) in refluxing ethanol/benzene to give 3,5-bis(het)arylisoxazoles 5, in which the het(aryl) moiety attached to thiocarbonyl group of the monothio-substituted 1,3-diketones is installed at the 3-position. On the other hand, the reaction of hydroxylamine hydrochloride with 3-(methylthio)-1,3-bis(het)aryl-2-propenones 2 in the presence of barium hydroxide in refluxing ethanol gave 3,5-bis(het) arylisoxazoles 6 with complementary regioselectivity in high yields. A probable mechanism for the formation of regioisomeric isoxazoles 5 and 6 from precursors 1 and 2 has been suggested.
Cyclocondensation of Hydroxylamine with 1,3-Bis(het)arylmonothio 1,3-Diketones and 1,3-Bis(het)aryl-3-(methylthio)-2-propenones: Synthesis of 3,5-Bis(het)arylisoxazoles with Complementary Regioselectivity
Raghava, Byregowda,Parameshwarappa, Gangajji,Acharya, Anand,Swaroop, Toreshettahally R.,Rangappa, Kanchugarakoppal S.,Ila, Hiriyakkanavar
, p. 1882 - 1892 (2015/10/05)
Efficient routes for the regioselective synthesis of 3,5-bis(het)arylisoxazoles with complementary regioselectivity have been developed. The methods involve the cyclocondensation of hydroxylamine hydrochloride with either 1,3-bis(het)aryl-monothio-substituted 1,3-diketones 1 or with 3-methylthio-1,3-bis(het)aryl-2-propenones 2 under various reaction conditions. In the first protocol, diketones 1 were treated with hydroxylamine hydrochloride in the presence of sodium acetate/acetic acid (pH 2.2) in refluxing ethanol/benzene to give 3,5-bis(het)arylisoxazoles 5, in which the het(aryl) moiety attached to thiocarbonyl group of the monothio-substituted 1,3-diketones is installed at the 3-position. On the other hand, the reaction of hydroxylamine hydrochloride with 3-(methylthio)-1,3-bis(het)aryl-2-propenones 2 in the presence of barium hydroxide in refluxing ethanol gave 3,5-bis(het)arylisoxazoles 6 with complementary regioselectivity in high yields. A probable mechanism for the formation of regioisomeric isoxazoles 5 and 6 from precursors 1 and 2 has been suggested.
STUDIES ON ISOMERIC PYRIDYLISOXAZOLES
Belgodere, Elena,Bossio, Ricardo,Sio, Francesco De,Marcaccini, Stefano,Pepino, Roberto
, p. 501 - 504 (2007/10/02)
Data concerning the reaction between hydroxylamine hydrochloride and 1-(2-pyridyl)-3-phenyl- (I a) and 1-(2-thienyl)-3-phenyl-1,3-propanedione (I l) disagree with those previously reported in literature.The same reaction was also studied employing a series of 1,3-diketones-1-(pyridyl)-substituted I b-i.The direction of enolization of 1,3-diketones accounted for the isomeric isoxazoles formation.
