Sulfuric Acid → Indolo(3,2-b)carbazole

HRID 408066Notes

Reaction equation

HRID 408066 reaction equation
[CH2:1](C1C2C(=CC=CC=2)NC=1)[C:2]1[C:10]2[C:5](=[CH:6][CH:7]=[CH:8][CH:9]=2)[NH:4][CH:3]=1.C(O[CH2:28][CH3:29])(OCC)OCC.S(=O)(=O)(O)O>CO>[CH:7]1[CH:8]=[CH:9][CH:10]=[C:5]2[N:4]=[C:3]3[CH:1]=[C:2]4[C:3](=[N:4][C:5]5[C:10]4=[CH:9][CH:8]=[CH:7][CH:6]=5)[CH:29]=[C:28]3[C:6]=12

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 30713,3'-DiindolylmethaneHCID 31214Ethyl orthoformate

Product 1

HCID 114764Indolo(3,2-b)carbazoleYield 139.7%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

In a 2,000-ml three-necked flask that had been deaerated and filled with nitrogen were placed 50.69 g (205.8 millimoles) of 3,3′-methylenediindole and 30.55 g (206.1 millimoles) of triethyl orthoformate, then 640 g of methanol was added, and the mixture was stirred. To this mixture was added dropwise 5.0 g (51.5 millimoles) of concentrated sulfuric acid over 3 minutes and the mixture was heated under reflux for 1 hour. The mixture was cooled to room temperature and the reddish-brown crystals formed were collected by filtration and washed twice by reslurrying in 500 ml of methanol. The solvent was stripped off under reduced pressure and 36.8 g (143.8 millimoles, 69.9% yield) of indolo[3,2-b]carbazole was obtained as a reddish-brown powder.

Workup

  1. customIn a 2,000-ml three-necked flask that had been deaerated
  2. additionfilled with nitrogen
  3. temperaturethe mixture was heated
  4. temperatureunder reflux for 1 hour
  5. customthe reddish-brown crystals formed
  6. filtrationwere collected by filtration
  7. washwashed twice

Sources & evidence

ORD record
ord-994c19b05b484db3ba45a4cf4a4a3911
Source dataset
uspto-grants-2014_06
Patent number
US08758904B2

Reaction notes

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