Reactions under Pressure: Synthesis of Functionally Substituted Arylhydrazonal Derivatives as Precursors of Novel Pyridazines and Nicotinates
摘要:
Q-tube assisted multicomponent synthesis of novel arylhydrazonals, pyridazines and nicotinates has been explored. The target molecules have been prepared via one pot reaction of arylhydrazonals with activated methylene nitriles in either ethanolic piperidine, dimethyl acetylene dicarboxylate (DMAD), 1,4-diazobicyclo[2.2.2]octane (DABCO), or Ph3P under pressure. Such conditions make reaction time much shorter and yields higher as compared with those conducted under conventional conditions. The structures of products have been determined by X-ray crystallography and spectroscopic methods.
Efficient synthesis of 3-aroylcinnolines from aryl methyl ketones
作者:Nouria A Al-Awadi、Mohamed Hilmy Elnagdi、Yehia A Ibrahim、Kamini Kaul、Ajith Kumar
DOI:10.1016/s0040-4020(00)01141-8
日期:2001.2
An efficient synthesis of 3-aroylcinnolines starting from the appropriate arylmethylketones is described. The latter were converted in two steps to the corresponding 3-oxo-3-aryl-2-arylhydrazonopropanals, which upon acid catalyzed cyclization in conc. sulfuric acid or polyphosphoric acid (PPA) led to the corresponding 3-aroylcinnolines.
The reaction of 3-oxo-3-phenyl-2-phenylhydrazonal with functionally substituted and heteroaromatic substituted acetonitrile to yield arylazonicotinic acid derivatives and 5-arylsubstituted pyridines was established. In some cases the produced nicotinates could not be isolated as they underwent thermally induced 6π-electrocyclization yielding polynuclear pyridine derivatives.
Reassignment of the structures of condensation products of α-keto α′-formylarylhydrazones with ethyl cyanoacetate: a novel route to ethyl 5-arylazo-2-hydroxynicotinates
作者:Saleh M. Al-Mousawi、Moustafa Sherief Moustafa、Ismail Abdelshafy Abdelhamid、Mohamed Hilmy Elnagdi
DOI:10.1016/j.tetlet.2010.10.127
日期:2011.1
The condensation of α-keto α′-formylarylhydrazones with ethyl cyanoacetate afforded ethyl 5-arylazo-2-hydroxy-6-aryl (or alkyl) nicotinates. The structures of the reaction products could be established based on X-ray crystal structure determination.
An efficient ultrasonic-mediated one-pot synthesis of 2,3,6,7,9-pentaazabicyclo[3.3.1]nonanes via a N,N-dimethylformamide dimethylacetal catalyzed Mannich-like reaction
作者:Haider Behbehani、Hamada Mohamed Ibrahim
DOI:10.1039/c6ra09210a
日期:——
A novel and straightforward method for one-pot synthesis of functionalized 2,3,6,7,9-pentaazabicyclo[3.3.1]nonane derivatives has been developed. The process, which involves ultrasonic irradiation promoted Mannichreaction between 3-oxo-2-arylhydrazonopropanals and ammonia in acetic acid, is catalyzed by N,N-dimethylformamide dimethylacetal (DMF-DMA) and generates the target products in 80–93% yields
High-Pressure Metal-Free Catalyzed One-Pot Two-Component Synthetic Approach for New 5-Arylazopyrazolo[3,4-b]Pyridine Derivatives
作者:AbdElAziz A. Nayl、Hamada Mohamed Ibrahim、Kamal M. Dawood、Wael A. A. Arafa、Ahmed I. Abd-Elhamid、Ismail M. Ahmed、Mohamed A. Abdelgawad、Hazim M. Ali、Ibrahim Hotan Alsohaimi、Ashraf A. Aly、Stefan Bräse、Asmaa Kamal Mourad
DOI:10.3390/molecules27196369
日期:——
An appropriate and efficient Q-tube-assisted ammonium acetate-mediated protocol for the assembly of the hitherto unreported 5-arylazopyrazolo[3,4-b]pyridines was demonstrated. This methodology comprises the cyclocondensation reaction of 5-amino-2-phenyl-4H-pyrazol-3-one with an assortment of arylhydrazonals in an NH4OAc/AcOH buffer solution operating a Q-tube reactor. This versatile protocol exhibited
证明了一种合适且有效的 Q 管辅助乙酸铵介导的方案,用于组装迄今为止未报道的 5-芳基吡唑并[3,4- b ] 吡啶。该方法包括 5-氨基-2-苯基-4 H-吡唑-3-酮与各种芳基腙醛在 NH 4中的环缩合反应操作 Q 管反应器的 OAc/AcOH 缓冲溶液。这种多功能协议具有几个突出的优点:易于处理、条件温和、可扩展、底物范围广、安全(Q-tube 套件仅用于压制和密封)和高原子经济性。因此,与常规条件相比,在高压下进行此类反应并利用 Q 管反应器似乎更适合获得所需的产品。应用多种光谱方法和 X 射线单晶技术来确认目标化合物的拟议结构。