PREPARATION OF IODOTETRALONE




PREPARATION OF IODOTETRALONE


Via Diazotization

 


Reagent

Eq

Apparatus

 

 

 

Aminotetralone SM (MW: 189)

1.0

Multi-neck large flask

HCl (conc.)

0.5ml/1mmol SM

Mechanical stirrer

NaNO2 (MW: 69) / (H2O)

1.15 / (0.3ml/1mmol SM)

Additional funnel

KI (MW: 166) / (H2O)

2.3 / (1ml/1mmol)

Cold bath





Procedure

 

1.      Dissolve Aminotetralone in HCl (conc.).  Add iced-cold water [1].

2.      Cold to 0 oC.  Add dropwise NaNO2/water [2]

3.      Stir at 0 oC for 30 min..  Add dropwise KI/water [3]

4.      Warm to R.T. and let standing (no stirring) for 30 min [4]

5.      Dilute w/EtOAc.  Stir for 15 min

6.      Extract aqueous layer w/EtOAc

7.      Wash w/ 20% aq. Na2S2O3 then brine

8.      Dry organic layers w/MgSO4.  Filter [5].

9.      Concentrate on Rotovac ® Dark brown oil

10.  Chromatograph w/ 2% ® 5% EtOAc/Hex

11.  NMR w/ CDCl3.  Yield 65% as light yellow solid

 



Notes:

 

[1]  Transfer to large multi-neck flask. Amount of cold H2O: 0.5 - 1.0 ml/1mmol SM

[2]  Temp.: 0 -5 oC during addition

[3]  Temp.: 0 -5 oC during addition.  ¯ black appear

[4]   Brownish vapor(I2) ­. Black gum appear. Small work up: TLC

[5]  TLC w/ 5% EtOAc/Hex.  Product polar < SM

38318-050