2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → 1H-Pyrrolo[2,3-b]pyridine-5-carboxylic acid

HRID 1994191Notes

Reaction equation

HRID 1994191 reaction equation
C([Si](C)(C)[N:6]1[C:10]2=[N:11][CH:12]=[C:13]([C:15]([OH:17])=[O:16])[CH:14]=[C:9]2[CH2:8][CH2:7]1)(C)(C)C.C(C1C(=O)C(Cl)=C(Cl)C(=O)C=1C#N)#N.N1C2C(=CC=CC=2)C=N1>C(Cl)Cl.Cl.CO>[NH:6]1[C:10]2=[N:11][CH:12]=[C:13]([C:15]([OH:17])=[O:16])[CH:14]=[C:9]2[CH:8]=[CH:7]1

Participants

7

Reactant 3

HCID 67752,3-Dichloro-5,6-dicyano-1,4-benzoquinoneHCID 92211H-IndazoleHCID 58730941HCID 58730941, compound

Product 1

HCID 219070181H-Pyrrolo[2,3-b]pyridine-5-carboxylic acidYield 3%

Reagents, catalysts & solvents 3

HCID 313Hydrochloric AcidSolventHCID 887MethanolSolventHCID 6344DichloromethaneSolvent

Procedure

A solution of crude acid 10 in CH2Cl2 (5 mL) was treated with DDQ in small portions until TLC analysis revealed no starting material left. The mixture was concentrated to afford a solid residue containing azaindole 11. The residue was dissolved in a 5% solution of HCl in MeOH (5 mL), and stirred at r.t. After 1.5 h the mixture was concentrated and diluted with CHCl3 and saturated brine. The mixture was basified with 50% NaOH solution to pH 11. The organic layer was discarded. The aqueous layer was neutralized with 6 M HCl and extracted with AcOEt (4×). The combined organic extracts were dried (MgSO4), filtered and concentrated. The residue was purified by PTLC using CH2Cl2:MeOH=9:1 as eluent to afford acid 12 (3.19 mg, 3% over 3 steps). 1H NMR (400 MHz; CD3OD) δ 6.58 (d, J=3.5 Hz, 1H), 7.42 (d, J=3.5 Hz, 1H), 8.58 (d, J=2.0 Hz, 1H), 8.85 (d, J=1.7 Hz, 1H).

Workup

  1. waitleft
  2. concentrationThe mixture was concentrated
  3. customto afford a solid residue
  4. concentrationAfter 1.5 h the mixture was concentrated
  5. additiondiluted with CHCl3 and saturated brine
  6. extractionextracted with AcOEt (4×)
  7. dry with materialThe combined organic extracts were dried (MgSO4)
  8. filtrationfiltered
  9. concentrationconcentrated
  10. customThe residue was purified by PTLC

Sources & evidence

ORD record
ord-ef99ec69025f486d8fa5ca9033aa579b
Source dataset
uspto-grants-2010_01
Patent number
US07652137B2

Reaction notes

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