5-氨基吡唑与环状β-甲酰酯反应合成具有4-氯-5-氯乙基侧链的吡唑并[3,4- b ]吡啶,得到氨基吡唑二氢呋喃酮中间体,在三氯氧化磷中环化仅转化为4-氯-5-氯乙基吡唑并[3,4- b ]吡啶4(ab)占主要量。侧链与乙酸、硫脲和芳香胺形成角环导致形成三环呋喃[2,3- d ]吡唑并[2,3- b ]吡啶5(ab)、吡唑并[3,4- b ]噻吩并[2,3- d ]吡啶6(ab)和吡唑并[3,4- b ]吡咯并[2,3-d ]吡啶分别为7(an)。研究了C 4位取代基对吡唑并吡啶荧光性质的影响。此外,还研究了电子供体和卤素取代基对吡唑并吡咯并吡啶7(an)荧光性质的影响及其荧光量子产率。 荧光吡唑并[3,4- b ]吡啶环化杂环的合成
Use of sodium salt of cyclic β-formylester for synthesis of dihydro-2H-furo[2,3-d]pyrazolo[3,4-b]pyridines and pyrazolo[3,4-b]pyrrolo[2,3-d]pyridines
作者:Shivaraj P. Patil、Raghunath B. Toche
DOI:10.1007/s00706-011-0535-1
日期:2011.11
The chemoselective reaction of the sodium salt of alpha-formyl-gamma-butyrolactone and 5-aminopyrazole furnished dihydrofuro[2,3-d]pyrazolo[3,4-b]pyridine at two different reaction conditions, i.e., with NH4OAc or in refluxing AcOH. The same reactants when refluxed in MeOH and AcOH produced a pyrazolylamino dihydrofuranone derivative. A mixture of 2-chloroethyl-4-chloropyrazolopyridines and dihydrofuro[2,3-d]pyrazolo[3,4-b]pyridine derivatives was obtained on refluxing the intermediate dihydrofuranone in POCl3. A one-step synthesis of tricyclic pyrazolopyrrolopyridines and thienopyrazolopyridines resulted from SNAr reaction of 2-chloroethyl-4-chloropyrazolopyridines with primary aromatic amines and with thiourea.