Dimethyl Sulfoxide → 1-Benzyl-5-nitro-1H-indole

HRID 566376Notes

Reaction equation

HRID 566376 reaction equation
CS(C)=O.[OH-].[K+].[N+:7]([C:10]1[CH:11]=[C:12]2[C:16](=[CH:17][CH:18]=1)[NH:15][CH:14]=[CH:13]2)([O-:9])=[O:8].[CH2:19](Br)[C:20]1[CH:25]=[CH:24][CH:23]=[CH:22][CH:21]=1>O>[CH2:19]([N:15]1[C:16]2[C:12](=[CH:11][C:10]([N+:7]([O-:9])=[O:8])=[CH:18][CH:17]=2)[CH:13]=[CH:14]1)[C:20]1[CH:25]=[CH:24][CH:23]=[CH:22][CH:21]=1

Participants

6

Reactant 4

HCID 679Dimethyl SulfoxideHCID 7498Benzyl BromideHCID 14797Potassium HydroxideHCID 225235-Nitroindole

Product 1

HCID 98563511-Benzyl-5-nitro-1H-indoleYield 51%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
-10 °C

Procedure

Dry dimethylsulphoxide (20 ml) was added to potassium hydroxide (4.2 g, 0.074 mol) (crushed pellets) and the mixture was stirred under nitrogen for 5 mins. 5-Nitroindole (commerically available) (3.0 g, 0.019 mol) was then added and the red mixture stirred for 30 min at room temperature. The mixture was then cooled to −10° C., benzyl bromide (4.4 ml, 0.037 mol) was slowly added and the mixture stirred and allowed to warm to room temperature over a period of 40 mins. Water (50 ml) was then added and the mixture was extracted with diethyl ether (2×200 ml). The extracts were washed with water (4×50 ml), dried over sodium sulphate and evaporated to leave an oily solid. The excess benzyl bromide was removed by dissolving the whole in diethyl ether (50 ml), diluting this solution with 40-60 petrol (50 ml) and then gradually removing the diethyl ether in vacuo to leave a yellow solid suspended in the petrol. The solid was filtered, washed with copious amounts of 40-60 petrol and dried to give 1-benzyl-5-nitroindole (2.4 g, 51%) as a yellow solid, m.p. 102-104° C.; δH [2H6]-DMSO 8.53 (1H, s, 4-H), 8.00 (1H, d, J 9, 6-H), 7.78 (1H, s, 2-H), 7.68 (1H, d, J 9, 7-H), 7.36-7.20 (5H, m, 2′-H, 3′-H, 4′-H, 5′-H, 6′-H), 6.81 (1H, s, 3-H), 5.52 (2H, s, CH2).

Workup

  1. stirringthe red mixture stirred for 30 min at room temperature
  2. stirringthe mixture stirred
  3. temperatureto warm to room temperature over a period of 40 mins
  4. extractionthe mixture was extracted with diethyl ether (2×200 ml)
  5. washThe extracts were washed with water (4×50 ml)
  6. dry with materialdried over sodium sulphate
  7. customevaporated
  8. customto leave an oily solid
  9. customThe excess benzyl bromide was removed
  10. dissolutionby dissolving the whole in diethyl ether (50 ml)
  11. additiondiluting this solution with 40-60 petrol (50 ml)
  12. customgradually removing the diethyl ether in vacuo
  13. customto leave a yellow solid
  14. filtrationThe solid was filtered
  15. washwashed with copious amounts of 40-60 petrol
  16. customdried

Sources & evidence

ORD record
ord-1a2d46101b7b46c89ea0f999f61acc48
Source dataset
uspto-grants-2001_01
Patent number
US06174889B1

Reaction notes

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