Hydrochloric Acid → HCID 19380185, compound

HRID 2254025Notes

Reaction equation

HRID 2254025 reaction equation
C([C:4]1[C:5]([CH3:13])=[N:6][N:7]2[CH:12]=[CH:11][CH:10]=[CH:9][C:8]=12)(=O)C.[ClH:14].[N:15]([O-])=O.[Na+]>O>[ClH:14].[NH2:15][C:4]1[C:5]([CH3:13])=[N:6][N:7]2[CH:12]=[CH:11][CH:10]=[CH:9][C:8]=12

Participants

5

Reactant 3

HCID 313Hydrochloric AcidHCID 594324HCID 594324, compoundHCID 23668193Sodium Nitrite

Product 1

HCID 19380185HCID 19380185, compound

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

7 g. 3-Acetyl-2-methylpyrazolo[1,5-a]pyridine (see J. Org. Chem., 42, 443/1977) are dissolved in 140 ml. 6N hydrochloric acid and mixed dropwise at 0° C. with a solution of 5.52 g. sodium nitrite in water. After 2 hours, the ice-bath used for the cooling is removed and the reaction mixture is left to stand overnight at ambient temperature and then adjusted to pH 9. The precipitated nitroso compound (6.4 g.) is filtered off with suction and dissolved in about 150 ml. 2N hydrochloric acid. The nitroso compound is reduced with zinc dust analogously to Example 1.2. The crude product is chromatographed on silica gel with ethyl acetate. The product-containing fractions are evaporated, the residue is dissolved in ethanol and the solution is mixed with ethanolic hydrogen chloride. The precipitate which is obtained after some time is filtered off with suction and dried. There are obtained 3.1 g. (45% of theory) of the title compound; m.p. >275° C.; TLC (silica gel, ethyl acetate/acetone/glacial acetic acid/water 50:25:12.5:12.5 v/v/v/v): Rf =0.6.

Workup

  1. customis removed
  2. waitthe reaction mixture is left
  3. waitto stand overnight at ambient temperature
  4. filtrationThe precipitated nitroso compound (6.4 g.) is filtered off with suction
  5. dissolutiondissolved in about 150 ml
  6. customThe crude product is chromatographed on silica gel with ethyl acetate
  7. customThe product-containing fractions are evaporated
  8. dissolutionthe residue is dissolved in ethanol
  9. additionthe solution is mixed with ethanolic hydrogen chloride
  10. customThe precipitate which is obtained after some time
  11. filtrationis filtered off with suction
  12. customdried
  13. customThere are obtained 3.1 g

Sources & evidence

ORD record
ord-3a124fc3a5504d83a9d8f593ef5a7857
Source dataset
uspto-grants-1993_08
Patent number
US05234818

Reaction notes

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