Reaction #816417

Reaction equation

14

N-acetyl-7-amino-1,2,3,4-tetrahydroisoquinoline

trifluoroacetic acid

trifluoroacetic anhydride

→

compound 15

Yield 94.0%

N-acetyl-7-trifluoroacetamido-1,2,3,4-tetrahydroisoquinoline

Yield 94.0%

Solvents

CH2Cl2

Conditions

Workup

1. 1
   Temperaturecooled
2. 2
   workup.ADDITIONthe mixture is poured onto ice
3. 3
   Extractionextracted twice with CH2Cl2
4. 4
   Otherevaporated
5. 5
   OtherThe mixture is chromatographed on silica gel

Procedure

A solution of 14 (3.0 g, 17 mmol), trifluoroacetic acid (2 ml, 28 mmol) and trifluoroacetic anhydride (4 ml, 28 mmol) in CH2Cl2 is refluxed for 15 minutes, cooled, and the mixture is poured onto ice, extracted twice with CH2Cl2 and evaporated. The mixture is chromatographed on silica gel to give 4.5 g of compound 15 (94% yield). 1H NMR [300 MHz, (CD3)2SO], a 3:2 mixture of amide conformers doubling most signals, δ 11.24 (0.8H, s, NH), 11.21 (1.2H, s, NH), 7.55-7.40 (2H, m, H5.8), 7.22 (0.6H, s, H-6), 7.20 (0.4H, s, H-6), 4.64 (0.8H, s, ArCH2N), 4.57 (1.2H, s, ArCH2N), 3.65 (2H, t, ArCH2CH2N), 2.84 (1.2H, t, ArCH2CH2N), 2.73 (0.8H, t, ArCH2CH2N), 2.06 (1.2H, s, COCH3), 2.05 (1.8H, s COCH3).

Source