Polycyclic heterocycles with acidic N-H group VII. Synthesis of some polynuclear heterocyclic compounds derived from 5-phenyl-6-azauracile

Roman Buchtík,Jan Slouka,Jan Hlaváçek,Mikael Begtrup

doi:10.3998/ark.5550190.0007.507

Abstract

Diazonium salt 2 obtained by diazotisation of 3-[3-(6-azauracil-5-yl)-2-aminophenyl]-1,2dihydro-quinoxalin-3-one 1 was used as a starting compound for the preparation of corresponding 2-hydroxy, 2-chloro, 2-bromo, and 2-iodo derivatives 4-7 using SN1 or Sandmeyer reaction. The diazonium salt 2 was converted by reductive cleavage to 3-[3-(6azauracil-5-yl)phenyl]-1,2-dihydro-quinoxalin-2-one 3 and its coupling with malononitrile or ethyl cyanoacetylcarbamate gave corresponding hydrazones 9 or 10. Hydrazone 9 was converted to 4-arylazo-3,5-diaminopyrazole 11 via cyclization with hydrazine, and hydrazone 10 was cyclized to 1-[2-(6-azauracil-5-yl)-6-(3,4-dihydro-3-oxo-quinoxalin-2-yl)phenyl]-6-azauracil-5carbonitrile 12. The slow decomposition of diazonium salt 2 led to benzofuroderivative 13 that was also found as an undesired side product of all the above mentioned SN1 reactions. Hydrazino derivative 8, which is an intermediate of diazonium salt 2 reduction or hydrazone 10 hydrolysis, was cyclized, without prior isolation, to corresponding derivative [1,2,4]triazino[5,6-c]cinnoline 14.

Highlights

Great attention is currently paid to the compounds that may influence spatial arrangement of biomolecules, mainly in relationship with the research of the compounds, which could affect the conformation of prion proteins.3 From that reason, we have focused on some polynuclear N-H acids that might be interesting from this point of view.In this note, we have focused on the synthesis of the compounds containing a free-rotating 1,2-dihydro-quinoxaline and 6-azauracil cycles that are, in contrast to the compounds mentioned in the paper,4 connected by carbon atom in position 5
Great attention is currently paid to the compounds that may influence spatial arrangement of biomolecules, mainly in relationship with the research of the compounds, which could affect the ISSN 1424-6376
We have focused on the synthesis of the compounds containing a free-rotating 1,2-dihydro-quinoxaline and 6-azauracil cycles that are, in contrast to the compounds mentioned in the paper,4 connected by carbon atom in position 5

Summary

Introduction

Great attention is currently paid to the compounds that may influence spatial arrangement of biomolecules, mainly in relationship with the research of the compounds, which could affect the conformation of prion proteins.3 From that reason, we have focused on some polynuclear N-H acids that might be interesting from this point of view.In this note, we have focused on the synthesis of the compounds containing a free-rotating 1,2-dihydro-quinoxaline and 6-azauracil cycles that are, in contrast to the compounds mentioned in the paper,4 connected by carbon atom in position 5. 3-[3-(3,5-Dioxo-2,3,4,5-tetrahydro-[1,2,4]triazin-6-yl)-phenyl]-2,3-dihydro-quinoxalin-2-one (3) Compound 12 (530 mg, 1.50 mmol) was dissolved in 1% aqueous sodium hydroxide (60 mL) and sodium nitrite (196 mg, 2.83 mmol) was added to this solution.

Results

Conclusion