Синтез заміщених 2-гідразинохіназолін-4-онів як інтермедіатів для синтезу гетероциклічних сполук

• Main Authors: Danilchenko, S. Yu., Drushlyak, O. G., Kovalenko, S. M.
• Format: Article
• Language: Ukrainian
• Published: National University of Pharmacy 2014
• Subjects: 2-hydrazinoquinazolin-4-one; 2-thioxoquinazolin-4-one; hydrazine; nucleophilic substitution; UDC547.792; 547.865.5; 2-гидразинохиназолин-4-он; 2-тиоксохиназолин-4-он; гидразин; нуклеофильное замещение; УДК 547.792; 2-гідразинохіназолін-4-он; 2-тіоксохіназолін-4-он; гідразин; нуклеофільне заміщення
• Online Access: https://ophcj.nuph.edu.ua/article/view/ophcj.14.810

A suitable and effective scheme for the synthesis of 2-hydrazinoquinazolin-4-ones has been suggested and tested. It can provide a wide chemical diversity of the final products. The scheme developed starts from esters of 2-isothiocyanobenzoic acids, which easily form 3-substituted 2-thioxoquinazolin-4-ones with a high yield in the reaction with primary amines. When refluxing the latter in a heterogenic emulsion of dioxane and hydrazine hydrate the nucleophilic substitution of the sulfur atom occurs with 3-substituted 2-hydrazinoquinazolin-4-ones formation accumulated in the dioxane phase. After separation of the dioxane layer and dilution with water the precipitate of sufficiently pure target 2-hydrazinoquinazolin-4-ones is formed. Under these conductions there is no splitting of the amide group, which can be a part of substituents. But in case of amides of (4-oxo-2-thioxo-1,4-dihydroquinazolin-3(2H)-yl)acetic acid after inserting of the hydrazine substituent the cyclization occurs as a result of the intramolecular substitution of the amine residue of the amide fragment with formation of 2H-[1,2,4] triazino[3,4-b]quinazoline-3,6(1H,4H)-dione. The structure of the compounds synthesized has been proven by elemental analysis and 1H NMR spectroscopy data. The compounds obtained are promising synthones for construction of diversified heterocyclic systems, which can be of interest as potential pharmacological substances.