Reaction #1914827

Reaction equation

phenylalanine

iodine

→

4-iodo-L-phenylalanine

Yield 132.8%

Solvents

H2SO4

acetic acid

Conditions

Workup

1. 1
   workup.ADDITIONwere added
2. 2
   TemperatureThe mixture was cooled
3. 3
   Otherthe acetic acid was removed
4. 4
   workup.ADDITIONthe residue oil was diluted
5. 5
   workup.ADDITIONby adding 400 mL of water
6. 6
   ExtractionThe aqueous solution was extracted once with 100 mL ether and once with 100 of dichloromethane
7. 7
   workup.ADDITIONby adding solid NaOH
8. 8
   Otherto precipitate the crude product, which
9. 9
   Temperatureafter chilling
10. 10
    Filtrationwas filtered
11. 11
    Washrinsed with 800 mL of water and 300 mL of ethanol
12. 12
    OtherThe wet product was recrystallized from 200 mL of acetic acid

Procedure

Into a solution of 40.15 gm (0.243 mol) of phenylalanine in a mixture of 220 mL of acetic acid and 29 mL of concentrated H2SO4 was added 24.65 gm (0.097 mol) of powered iodine and 10. 18 gm (0.051 mol) of powered NaIO3 while stirring. The reaction mixture was stirred at 70° C. for 21 h, during this time, two portions of 1 gm of NaIO3 were added. The mixture was cooled and the acetic acid was removed by using rotavapor while temperature was maintained at 35° C. and the residue oil was diluted by adding 400 mL of water. The aqueous solution was extracted once with 100 mL ether and once with 100 of dichloromethane. After decolorization with 5 gm of Norit, the aqueous solution was neutralized by adding solid NaOH to precipitate the crude product, which, after chilling, was filtered and rinsed with 800 mL of water and 300 mL of ethanol. The wet product was recrystallized from 200 mL of acetic acid to produce 37.5 gm of 4-iodo-L-phenylalanine.

Source