3-Nitrobenzaldehyde → 27185-21-3

HRID 1868617Notes

Reaction equation

HRID 1868617 reaction equation
[NH2:1][C:2]1[NH:3][C:4]2[CH:10]=[CH:9][CH:8]=[CH:7][C:5]=2[N:6]=1.[N+]([C:14]1[CH:15]=[C:16]([CH:19]=[CH:20][CH:21]=1)[CH:17]=O)([O-])=O.C(N(C(C)C)CC)(C)C.[BH4-].[Na+]>CO.C1(C)C=CC=CC=1>[CH2:17]([NH:1][C:2]1[NH:3][C:4]2[CH:10]=[CH:9][CH:8]=[CH:7][C:5]=2[N:6]=1)[C:16]1[CH:19]=[CH:20][CH:21]=[CH:14][CH:15]=1

Participants

7

Reactant 4

HCID 74493-NitrobenzaldehydeHCID 136242-AminobenzimidazoleHCID 81531DiisopropylethylamineHCID 4311764Sodium borohydride

Product 1

HCID 56344627185-21-3Yield 15.8%

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 1140TolueneSolvent

Conditions

Temperature
0 °C

Procedure

A 100 mL flask was charged with 1.0 g 2-aminobenzimidazole (7.51 mmol, 1.0 equiv), 1.13 g 3-nitrobenzaldehyde (7.51 mmol, 1.0 equiv), and 25 mL toluene. The flask was equipped with a Dean-Stark trap and reflux condenser and placed in a 110° C. bath. The solution was refluxed for 15.5 h, followed by the addition of 3 mL MeOH and 3 mL diisopropylethylamine. After refluxing an additional 29 h, the flask was removed, and the volatiles were removed under reduced pressure at 70° C. The remaining material was diluted with 50 mL MeOH, and cooled to 0° C. followed by the addition of 426 mg (11.27 mmol, 1.5 equiv) NaBH4. After stirring for 3 h, the solution was concentrated under reduced pressure, and the residue was applied directly to a SiO2 column (preflushed with 10% MeOH/CH2Cl2). The column was eluted with 10% MeOH/CH2Cl2 to give the product as an orange solid 320 mg (1.19 mmol). 1H NMR (DMSO-d6, 400 MHz) δ 11.0 (broad s, 1H), 8.25 (s, 1H), 8.11 (d, J=8.2 Hz, 1H), 7.85 (d, J=7.5 Hz, 1H), 7.62 (t, J=8.0 Hz, 1H), 7.34 (m, 1H), 7.13 (t, J=3.7 Hz, 2 H), 6.86 (s, 2H), 4.64 (d, J=5.8 Hz, 2H); MS: ESI(+) m/z 269.2 (M+H+).

Workup

  1. customThe flask was equipped with a Dean-Stark trap
  2. temperaturereflux condenser
  3. customplaced in a 110° C.
  4. temperatureThe solution was refluxed for 15.5 h
  5. temperatureAfter refluxing an additional 29 h
  6. customthe flask was removed
  7. customthe volatiles were removed under reduced pressure at 70° C
  8. additionThe remaining material was diluted with 50 mL MeOH
  9. concentrationthe solution was concentrated under reduced pressure
  10. washThe column was eluted with 10% MeOH/CH2Cl2

Sources & evidence

ORD record
ord-fa7534a0f81c4779b7378cd5e3a3f4b5
Source dataset
uspto-grants-2009_12
Patent number
US07635774B2

Reaction notes

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