Study of cyclyzation of o-(1-Alkynyl)- and o-(1,3-Butadiynyl)aryltriazenes under the action of acids
摘要:
The investigation of Richter cyclization of o-(1-alkynyl)- and o-(1,3-butadiynyl)arenediazonium salts generated by acid cleavage of triazenes was carried out by the methods of NMR and ESI MS (Electrospray Ionization Mass Spectrometry). The effect was shown of the substituents at the carbon atom of the triple bond and in the aromatic ring, of the solvent, temperature, and the reagents ratio on the rate of the cyclization and the yield of its products, 4-bromo-3-alkyl- and 4-bromo-3-ethynylcinnolines; the conditions of their synthesis were optimized. The possibility to use 4-bromo-3-ethynylcinnolines as substrates of electrophilic cyclization was demonstrated.
A short route to 3-alkynyl-4-bromo(chloro)cinnolines by Richter-type cyclization of ortho-(dodeca-1,3-diynyl)aryltriaz-1-enes
摘要:
Cleavage of ortho-(dodeca-1,3-diynyl)triazenes in HCl or HBr medium and subsequent cyclization of the resulting diazonium salts is investigated. In the absence of a strong electron-withdrawing substituent, the reaction affords 3-alkynyl-4-bromo(chloro)cinnolines as the only product. A methoxycarbonyl group promotes hydrolysis of 4-halocinnolines which results in the formation of by-products: furo[3,2-c]cinnoline and cinnolinone. Substitution of bromine in 3-(alk-1-ynyl)-4-bromocinnolines is achieved with methylamine, Na2S and ethynylbenzene affording pyrrolo[3,2-c]cinnoline, thieno[3,2-c]cinnoline and 3,4-diethynylcinnoline, respectively. (C) 2009 Elsevier Ltd. All rights reserved.
A short route to 3-alkynyl-4-bromo(chloro)cinnolines by Richter-type cyclization of ortho-(dodeca-1,3-diynyl)aryltriaz-1-enes
作者:Olga V. Vinogradova、Viktor N. Sorokoumov、Irina A. Balova
DOI:10.1016/j.tetlet.2009.08.103
日期:2009.11
Cleavage of ortho-(dodeca-1,3-diynyl)triazenes in HCl or HBr medium and subsequent cyclization of the resulting diazonium salts is investigated. In the absence of a strong electron-withdrawing substituent, the reaction affords 3-alkynyl-4-bromo(chloro)cinnolines as the only product. A methoxycarbonyl group promotes hydrolysis of 4-halocinnolines which results in the formation of by-products: furo[3,2-c]cinnoline and cinnolinone. Substitution of bromine in 3-(alk-1-ynyl)-4-bromocinnolines is achieved with methylamine, Na2S and ethynylbenzene affording pyrrolo[3,2-c]cinnoline, thieno[3,2-c]cinnoline and 3,4-diethynylcinnoline, respectively. (C) 2009 Elsevier Ltd. All rights reserved.
Study of cyclyzation of o-(1-Alkynyl)- and o-(1,3-Butadiynyl)aryltriazenes under the action of acids
作者:N. A. Danilkina、E. G. Gorbunova、V. N. Sorokoumov、I. A. Balova
DOI:10.1134/s1070428012110048
日期:2012.11
The investigation of Richter cyclization of o-(1-alkynyl)- and o-(1,3-butadiynyl)arenediazonium salts generated by acid cleavage of triazenes was carried out by the methods of NMR and ESI MS (Electrospray Ionization Mass Spectrometry). The effect was shown of the substituents at the carbon atom of the triple bond and in the aromatic ring, of the solvent, temperature, and the reagents ratio on the rate of the cyclization and the yield of its products, 4-bromo-3-alkyl- and 4-bromo-3-ethynylcinnolines; the conditions of their synthesis were optimized. The possibility to use 4-bromo-3-ethynylcinnolines as substrates of electrophilic cyclization was demonstrated.