Stereoisomerism and Ring??Chain Tautomerism in 1??Hydroxy??2, 3??dihydro??1H??pyrazolo [1, 2??a] pyridazine??5, 8??diones and 1??Hydroxy??and 1??Amino??2, 3??dihydro?? …

…, IP Bezhan, BA Chakchir, F Al??Assar…

Index: Sinkkonen, Jari; Ovcharenko, Vladimir; Zelenin, Kirill N.; Bezhan, Irina P.; Chakchir, Boris A.; Al-Assar, Fatema; Pihlaja, Kalevi European Journal of Organic Chemistry, 2002 , # 20 p. 3447 - 3454

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Citation Number: 3

Abstract

Abstract 1-Hydroxy-2, 3-dihydro-1H-pyrazolo [1, 2-a] pyridazine-5, 8diones and 1-hydroxy- and 1-amino-2, 3-dihydro-1H-pyrazolo [1, 2-b] phthalazine-5, 10-diones were synthesized and their structures studied by NMR and MS methods. All compounds exist in similar cyclic forms in solution, except for 1hydroxy-1-methyl-2, 3-dihydro-1H-pyrazolo [1, 2-a] pyridazine- 5, 8-dione, which displays ring-chain tautomerism in CDCl 3 solution. The corresponding ...