Hydrazine hydrate (1:1) → 3-Methylisoquinolin-8-amine

HRID 1902545Notes

Reaction equation

HRID 1902545 reaction equation
Br[C:2]1[CH:11]=[CH:10][C:9]([N+:12]([O-])=O)=[C:8]2[C:3]=1[CH:4]=[C:5]([CH3:15])[N:6]=[CH:7]2.O.NN>C(O)C.[Pd]>[NH2:12][C:9]1[CH:10]=[CH:11][CH:2]=[C:3]2[C:8]=1[CH:7]=[N:6][C:5]([CH3:15])=[CH:4]2

Participants

5

Reactant 2

HCID 24654Hydrazine hydrate (1:1)HCID 205156395-Bromo-3-methyl-8-nitroisoquinoline

Product 1

HCID 205156383-Methylisoquinolin-8-amineYield 68.8%

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 702EthanolSolvent

Procedure

A catalyst consisting of palladium-on-carbon (3/97 by weight; 5 g) is added to a solution of 5-bromo-3-methyl-8-nitroisoquinoline (10.8 g) in ethanol (200 cc). The suspension is stirred, whilst heating to the reflux temperature under a nitrogen atmosphere, and hydrazine hydrate (25 cc) is added dropwise in the course of 30 minutes. The mixture is then heated under reflux for a further 2 hours. The suspension is filtered hot through diatomaceous silica and the filtrate is concentrated to dryness under reduced pressure (20 mm Hg; 2.7 kPa) at 40° C. The residue is dissolved in 0.5 N aqueous hydrochloric acid (200 cc) and the resulting solution is extracted with methylene chloride (2×50 cc). The aqueous phase is then rendered alkaline to pH 10 by addition of sodium hydroxide and is extracted with methylene chloride (3×150 cc). The organic extracts are combined, washed with water, dried over magnesium sulphate and filtered and the filtrate is concentrated to dryness under reduced pressure (20 mm Hg; 2.7 kPa) at 40° C. to yield 8-amino-3-methylisoquinoline (4.4 g), which is a beige solid, m.p.=175° C.

Workup

  1. temperaturewhilst heating to the reflux temperature under a nitrogen atmosphere
  2. temperatureThe mixture is then heated
  3. temperatureunder reflux for a further 2 hours
  4. filtrationThe suspension is filtered hot through diatomaceous silica
  5. concentrationthe filtrate is concentrated to dryness under reduced pressure (20 mm Hg; 2.7 kPa) at 40° C
  6. dissolutionThe residue is dissolved in 0.5 N aqueous hydrochloric acid (200 cc)
  7. extractionthe resulting solution is extracted with methylene chloride (2×50 cc)
  8. additionby addition of sodium hydroxide
  9. extractionis extracted with methylene chloride (3×150 cc)
  10. washwashed with water
  11. dry with materialdried over magnesium sulphate
  12. filtrationfiltered
  13. concentrationthe filtrate is concentrated to dryness under reduced pressure (20 mm Hg; 2.7 kPa) at 40° C.

Sources & evidence

ORD record
ord-225b16c502fc497da6d3085ab6f1461c
Source dataset
uspto-grants-1982_12
Patent number
US04363909

Reaction notes

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