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-1H-pyrazolo[1,2-b]phthalazine-5,10-diones
作者:Jari Sinkkonen、Vladimir Ovcharenko、Kirill N. Zelenin、Irina P. Bezhan、Boris A. Chakchir、Fatema Al-Assar、Kalevi Pihlaja
DOI:10.1002/1099-0690(200210)2002:20<3447::aid-ejoc3447>3.0.co;2-l
日期:2002.10
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 CDCl3 solution. The corresponding 3-methyl-substituted derivatives exhibit a typical cis/trans isomerism as a result of latent ring-chain-ring tautomerism. The structures of
1-羟基-2,3-二氢-1 H-吡唑并[1,2- a ]哒嗪-5,8二酮和1-羟基-和1-氨基-2,3-二氢-1 H-吡唑并[1,2 - b ]酞嗪-5,10-二酮的合成和研究了用NMR和MS方法对其结构。除了1hydroxy-1-methyl-2,3-dihydro-1 H -pyrazolo [1,2- a ] pyridazine-5,8-dione以外,所有化合物都以相似的环状形式存在于溶液中。 CDCl 3溶液。相应的3-甲基取代的衍生物表现出典型的顺/反潜在的环-链-环互变异构导致的异构现象。由核磁共振结果得出的立体异构体结构还通过密度泛函计算得到证实。质谱结果表明1-羟基衍生物的分子离子在气相中的开链结构和1-氨基衍生物的环状结构。(©Wiley-VCH Verlag GmbH,69451 Weinheim,Germany,2002)