Reaktion #60767

Reaktionsgleichung

ammonium hydroxide

4-Amino-3-(4-nitrophenyl)thieno[2,3-d]pyrimidine

HCl

tin

→

4-Amino-3-(4-aminophenyl)thieno[2,3-d]pyrimidine

Lösungsmittel

ethyl acetate

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeThe system was placed in an ice bath
2. 2
   SonstigeAt this point, extensive precipitation
3. 3
   FiltrationPrecipitate (A) was collected by filtration
4. 4
   workup.ADDITIONthe clear solution was treated with 1 L methylene chloride
5. 5
   ExtraktionThe aqueous layer was then back-extracted with 3×200 mL methylene chloride
6. 6
   Trocknendried over anhydrous sodium sulfate
7. 7
   Filtrationfiltered
8. 8
   workup.ADDITIONPrecipitate (A), consisting of a mixture of tin salts and product
9. 9
   Extraktionwas extracted with boiling methanol until washings
10. 10
    Filtrationfiltered
11. 11
    Einengenconcentrated to dryness
12. 12
    Sonstigedried overnight
13. 13
    Sonstigenearly quantitative yield), which was recrystallized from methanol

Vorschrift

4-Amino-3-(4-nitrophenyl)thieno[2,3-d]pyrimidine (11.6 g; 272 g/mole; 42.6 mmoles) was treated with 500 mL HCl 6N and 15 g elemental tin at room temperature. After 15 minutes the reaction was complete by TLC (product has Rf=0.50 in 100% ethyl acetate). The system was placed in an ice bath and treated with concentrated ammonium hydroxide to pH 10 (˜300 mL). At this point, extensive precipitation was observed. Precipitate (A) was collected by filtration and reserved, and the clear solution was treated with 1 L methylene chloride. The aqueous layer was then back-extracted with 3×200 mL methylene chloride. The organic layers were combined, dried over anhydrous sodium sulfate, and filtered. Precipitate (A), consisting of a mixture of tin salts and product, was extracted with boiling methanol until washings showed no more product by TLC. The resulting solution was combined with the previously reserved organic layers, filtered, concentrated to dryness and dried overnight, generating desired product 4-Amino-3-(4-aminophenyl)thieno[2,3-d]pyrimidine (242 g/mole; nearly quantitative yield), which was recrystallized from methanol.

Quelle