Molecules 2012, 17(6), 6547-6556; doi:10.3390/molecules17066547
Article

Condensation Reactions of 3-Oxo-2-arylhydrazonopropanals with Active Methylene Reagents: Formation of 2-Hydroxy- and 2-Amino-6-substituted-5-arylazonicotinates and Pyrido[3,2-c]cinnolines via 6π-Electrocyclization Reactions

1,* email and 1,2
Received: 18 May 2012; in revised form: 25 May 2012 / Accepted: 25 May 2012 / Published: 30 May 2012
(This article belongs to the Section Theoretical Chemistry)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: 3-Oxo-3-phenyl-2-(p-tolylhydrazono)propanal (1a) undergoes condensation with ethyl cyanoacetate in acetic acid in the presence of ammonium acetate to yield either 2-hydroxy-6-phenyl-5-p-tolylazonicotinic acid ethyl ester (6a) or 2-amino-6-phenyl-5-p-tolyl-azonicotinic acid ethyl ester (8), depending on the reaction conditions. Similarly, other 3-oxo-3-aryl-2-arylhydrazonopropanals 1a,b condense with active methylene nitriles 2c,d to yield arylazonicotinates 6b,c. In contrast, 2-[(4-nitrophenyl)-hydrazono]-3-oxo-3-phenyl-propanal (1c) reacts with ethyl cyanoacetate to yield ethyl 6-(4-nitrophenyl)-2-oxo-2,6-dihydropyrido[3,2–c]cinnoline-3-carboxylate (11), via a novel 6π-electrocyclization pathway. Finally, 3-oxo-2-(phenylhydrazono)-3-p-tolylpropanal (1d) condenses with 2a–c to yield pyridazinones 13a–c.
Keywords: arylhydrazonopropanals; arylazonicotinates; pyridazinones; cinnolines
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MDPI and ACS Style

Al-Mousawi, S.M.; El-Apasery, M.A. Condensation Reactions of 3-Oxo-2-arylhydrazonopropanals with Active Methylene Reagents: Formation of 2-Hydroxy- and 2-Amino-6-substituted-5-arylazonicotinates and Pyrido[3,2-c]cinnolines via 6π-Electrocyclization Reactions. Molecules 2012, 17, 6547-6556.

AMA Style

Al-Mousawi SM, El-Apasery MA. Condensation Reactions of 3-Oxo-2-arylhydrazonopropanals with Active Methylene Reagents: Formation of 2-Hydroxy- and 2-Amino-6-substituted-5-arylazonicotinates and Pyrido[3,2-c]cinnolines via 6π-Electrocyclization Reactions. Molecules. 2012; 17(6):6547-6556.

Chicago/Turabian Style

Al-Mousawi, Saleh M.; El-Apasery, Morsy A. 2012. "Condensation Reactions of 3-Oxo-2-arylhydrazonopropanals with Active Methylene Reagents: Formation of 2-Hydroxy- and 2-Amino-6-substituted-5-arylazonicotinates and Pyrido[3,2-c]cinnolines via 6π-Electrocyclization Reactions." Molecules 17, no. 6: 6547-6556.

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