Phosphorus oxide (P4O10) → 1-ethyl-3,4-dihydroisoquinoline

HRID 369993Notes

Reaction equation

HRID 369993 reaction equation
[C:1]1([CH2:7][CH2:8][NH:9][C:10](=O)[CH2:11][CH3:12])[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.O=P12OP3(OP(OP(O3)(O1)=O)(=O)O2)=O>C1C2C(=CC=CC=2)CCC1>[CH2:11]([C:10]1[C:6]2[C:1](=[CH:2][CH:3]=[CH:4][CH:5]=2)[CH2:7][CH2:8][N:9]=1)[CH3:12]

Participants

4

Reactant 2

HCID 14812Phosphorus oxide (P4O10)2×HCID 94894N-(2-Phenylethyl)propanamide

Product 1

HCID 109098511-ethyl-3,4-dihydroisoquinolineYield 55.7%

Reagents, catalysts & solvents 1

HCID 8404TetralinSolvent

Procedure

A mixture of N-(2-phenylethyl)-propionamide (10 g, 56.4 mmol) and phosphorus pentoxide (80 g, 563 mmol) in tetralin (500 ml) was heated at reflux for 15 min, cooled, further phosphorus pentoxide (80 g) was added and reflux was resumed for 15 min. After standing overnight the tetralin was decanted, the residue was decomposed with ice-water, the suspension was filtered through celite and washed with two portions of ether. The aqueous solution was basified with concentrated ammonium hydroxide, extracted with three portions of ether, the extracts were dried (MgSO4) and the solvent was evaporated giving a red solid (5.0 g, 55.7%); MS [M+H]+ 160.

Workup

  1. temperaturewas heated
  2. temperatureat reflux for 15 min
  3. temperaturecooled
  4. temperaturereflux
  5. waitAfter standing overnight
  6. customthe tetralin was decanted
  7. filtrationthe suspension was filtered through celite
  8. washwashed with two portions of ether
  9. extractionextracted with three portions of ether
  10. dry with materialthe extracts were dried (MgSO4)
  11. customthe solvent was evaporated

Sources & evidence

ORD record
ord-667c7e0c523e4ebb92e74babc2b516e8
Source dataset
uspto-grants-2000_10
Patent number
US06140322

Reaction notes

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