methyl 1H-indole-5-carboxylate → methyl 2,3-dihydro-1H-indole-5-carboxylate

HRID 252802Notes

Reaction equation

HRID 252802 reaction equation
[NH:1]1[C:9]2[C:4](=[CH:5][C:6]([C:10]([O:12][CH3:13])=[O:11])=[CH:7][CH:8]=2)[CH:3]=[CH:2]1.C([BH3-])#N.[Na+]>C(O)(=O)C>[NH:1]1[C:9]2[C:4](=[CH:5][C:6]([C:10]([O:12][CH3:13])=[O:11])=[CH:7][CH:8]=2)[CH2:3][CH2:2]1

Participants

4

Reactant 2

HCID 2737635methyl 1H-indole-5-carboxylateHCID 5003444Sodium cyanoborohydride

Product 1

HCID 21782110methyl 2,3-dihydro-1H-indole-5-carboxylateYield 80.2%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

To a cold solution of methyl indole-5-carboxylate (2 g, 11.4 mmol) in glacial acetic acid at 0° C. (15 ml) sodium cyanoborohydride (1.075 g, 17.1 mmol) was slowly added. The mixture was allowed to warm-up and stirred at room temperature for one more hour, cooled again to 0° C. and quenched with H2O. The pH of the resultant solution was adjusted to the value of 12 by adding aqueous NaOH, extracted with DCM, washed with brine and dried over MgSO4. The dried extract was concentrated in vacuum and purified by flash chromatography (eluent 30% EtOAc in hexane) to give the title compound 20 (1.62 g, 80%) as a beige solid. 1H-NMR (DMSO) δ: 2.94 (t, J=8.6 Hz, 2H); 3.51 (dt, J=1.2, 8.6 Hz, 2H); 3.71 (s, 3H); 6.42 (d, J=8.0 Hz, 2H); 7.54 (m, 2H).

Workup

  1. temperatureto warm-up
  2. temperaturecooled again to 0° C.
  3. customquenched with H2O
  4. additionby adding aqueous NaOH
  5. extractionextracted with DCM
  6. washwashed with brine
  7. dry with materialdried over MgSO4
  8. extractionThe dried extract
  9. concentrationwas concentrated in vacuum
  10. custompurified by flash chromatography (eluent 30% EtOAc in hexane)

Sources & evidence

ORD record
ord-ab33ee3f36ad4010989a45dab3859c2d
Source dataset
uspto-grants-2011_01
Patent number
US07868205B2

Reaction notes

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