Quinoxaline

Structural formula

• Numbering system
• Physical property data
• Toxicological data
• Ecological data
• Molecular structure data
• Computing chemical data
• More
  • Properties and Stability
  • Storage method
  • Synthesis method
  • Purpose

Numbering system

CAS number:91-19-0

MDL number:MFCD00006719

EINECS number:202-047-4

RTECS number:VD1225000

BRN number:109351

PubChem number:24853610

Physical property data

1. Properties: white crystal.

2. Density (g/mL, 40/4℃): 1.1334

3. Relative vapor density (g/mL, air=1): Undetermined

4. Melting point (ºC): 30

5. Boiling point (ºC, normal pressure): Undetermined

6. Boiling point (ºC, 2.26kpa): 112～115

7. Refractive index: 1.6231

8. Flash point (ºC): Undetermined

9. Specific rotation (º): Undetermined

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10. Autoignition point or ignition temperature (ºC): Undetermined

11. Vapor pressure (kPa, 25ºC): Undetermined

12. Saturated vapor pressure (kPa, 60ºC): Undetermined

13. Heat of combustion (KJ/mol): Undetermined

14. Critical temperature (ºC): Undetermined

15. Critical pressure (KPa): Undetermined

16. Log value of oil-water (octanol/water) partition coefficient: Undetermined

17. Explosion upper limit (%, V /V): Undetermined

18. Lower explosion limit (%, V/V): Undetermined

19. Solubility: Soluble in water, ethanol, ether, acetone and benzene .

Toxicological data

None

Ecological data

None

Molecular structure data

1. Molar refractive index: 40.27

2. Molar volume (cm³/mol): 109.9

3. Isotonic specific volume (90.2K ): 299.4

4. Surface tension (dyne/cm): 54.8

5. Polarizability (10-24cm3): 15.96

Compute chemical data

1. Reference value for hydrophobic parameter calculation (XlogP): None

2. Number of hydrogen bond donors: 0

3. Number of hydrogen bond acceptors: 2

4. Number of rotatable chemical bonds: 0

5. Number of tautomers: none

6. Topological molecule polar surface area 25.8

7. Number of heavy atoms: 10

8. Surface charge: 0

9. Complexity: 99.8

10. Number of isotope atoms: 0

11. Determine the atomsNumber of stereocenters: 0

12. Number of uncertain atom stereocenters: 0

13. Determined number of stereocenters of chemical bonds: 0

14 .The number of uncertain chemical bond stereocenters: 0

15. The number of covalent bond units: 1

Properties and stability

Weakly alkaline, pKa≈0.8 (water, 20℃). The melting point of hydrogen chloride salt is 184℃, and the melting point of sulfate is 186~187℃. Forms quaternary ammonium salt with methyl iodide (melting point 175°C). It is difficult to carry out substitution reaction with electrophilic reagents, and its reaction with nucleophiles is similar to that of pyrazine.

Storage method

Should be sealed and stored in a cool place.

Synthesis method

It is produced by the reaction of catechol and ethylenediamine, and the product is then dehydrogenated. Or it is obtained by cyclization of o-phenylenediamine and glyoxal: add water to the reaction pot, add sodium bisulfite, stir, slowly add glyoxal, the temperature rises to 75-80°C, and white crystals precipitate. Continue stirring for 10 minutes, add water and o-phenylenediamine, and keep it at 75-80°C for 1 hour. Cool to 50°C, neutralize with sodium carbonate to pH=8, heat to 60°C, let stand and separate the water layer to obtain benzopyrazine with a content of 80%, and a yield of 90%.

Purpose

Used as a reagent for organic synthesis. Used as an intermediate for the anti-tuberculosis drug pyrazinamide.