1,2,3,4-Tetrahydroisoquinoline → 3,4-Dihydroisoquinoline

HRID 1723466Notes

Reaction equation

HRID 1723466 reaction equation
[CH2:1]1[C:10]2[C:5](=[CH:6][CH:7]=[CH:8][CH:9]=2)[CH2:4][CH2:3][NH:2]1.[S]>C1(C)C=CC=CC=1>[CH:1]1[C:10]2[C:5](=[CH:6][CH:7]=[CH:8][CH:9]=2)[CH2:4][CH2:3][N:2]=1

Participants

4

Reactant 2

HCID 70461,2,3,4-TetrahydroisoquinolineHCID 5362487Sulfur2×

Product 1

HCID 767053,4-DihydroisoquinolineYield 96.5%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

30.0 g of 1,2,3,4-tetrahydroisoquinoline and 15.0 g of sulphur powder in 200 ml of toluene are refluxed for 6 hours. After cooling the precipitating sulphur is filtered off, the filtrate is extracted with 200 ml of 5% hydrochloric acid. The aqueous solution is made alkaline with 40% sodium hydroxide to pH=10, then extracted with 250 ml of chloroform. The chloroform extract is dried with sodium sulfate and evaporated in vacuo. As residue 28.5 g of 3,4-dihydroisoquinoline are obtained.

Workup

  1. filtrationis filtered off
  2. extractionthe filtrate is extracted with 200 ml of 5% hydrochloric acid
  3. extractionextracted with 250 ml of chloroform
  4. extractionThe chloroform extract
  5. dry with materialis dried with sodium sulfate
  6. customevaporated in vacuo

Sources & evidence

ORD record
ord-84bab710490641c2b6c1b3e1eebbd112
Source dataset
uspto-grants-1989_08
Patent number
US04861888

Reaction notes

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