Triethylamine → Phthalazine

HRID 1531771Notes

Reaction equation

HRID 1531771 reaction equation
N=[N+]=[N-].Cl[C:5]1[C:14]2[C:9](=[CH:10][CH:11]=[CH:12][CH:13]=2)[C:8](Cl)=[N:7][N:6]=1.C(N(CC)CC)C>C1(C)C(C)=CC=CC=1>[CH:5]1[C:14]2[C:9](=[CH:10][CH:11]=[CH:12][CH:13]=2)[CH:8]=[N:7][N:6]=1

Participants

5

Reactant 3

HCID 8471TriethylamineHCID 24530Hydrazoic acidHCID 784901,4-Dichlorophthalazine

Product 1

HCID 9207PhthalazineYield 15.1%

Reagents, catalysts & solvents 1

HCID 7237O-XyleneSolvent

Procedure

A mixture of the preceding hydrazoic acid (798 mg, 3.91 mmol), 1,4-dichlorophthalazine (778 mg, 3.91 mmol) and triethylamine (0.54 ml, 3.9 mmol) in xylene (28 ml) was heated at reflux under nitrogen for 20.5 h. The mixture was cooled to room temperature, the solvent evaporated in vacuo and the residue partitioned between dichloromethane and water. The aqueous was separated and re-extracted with dichloromethane (×2). The combined extracts were dried (MgSO4), evaporated in vacuo and the residue chromatographed on silica gel eluting with ethyl acetate, then 5% methanol/dichloromethane to afford the title-phthalazine (77 mg, 6%), 1H NMR (360 MHz, CDCl3/d6-DMSO) δ 7.51 (1H, m, Ar—H), 7.55 (1H, s, Ar—H), 7.99 (1H, m, Ar—H), 8.11 (1H, m, Ar—H), 8.24 (1H, m, Ar—H), 8.38 (1H, d, J=7.8 Hz, Ar—H), 8.78 (1H, m, Ar—H), 8.83 (1H, m, Ar—H), 9.18 (1H, br s, Ar—H); MS (ES30) m/e 349 [MH]+.

Workup

  1. temperaturewas heated
  2. temperatureat reflux under nitrogen for 20.5 h
  3. customthe solvent evaporated in vacuo
  4. customthe residue partitioned between dichloromethane and water
  5. customThe aqueous was separated
  6. extractionre-extracted with dichloromethane (×2)
  7. dry with materialThe combined extracts were dried (MgSO4)
  8. customevaporated in vacuo
  9. customthe residue chromatographed on silica gel eluting with ethyl acetate

Sources & evidence

ORD record
ord-a3a04fbc84674156b7e715a0ca3bd139
Source dataset
uspto-grants-2001_03
Patent number
US06200975B1

Reaction notes

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