反应详情

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.

1. customThe system was placed in an ice bath
2. customAt this point, extensive precipitation
3. filtrationPrecipitate (A) was collected by filtration
4. additionthe clear solution was treated with 1 L methylene chloride
5. extractionThe aqueous layer was then back-extracted with 3×200 mL methylene chloride
6. dry with materialdried over anhydrous sodium sulfate
7. filtrationfiltered
8. additionPrecipitate (A), consisting of a mixture of tin salts and product
9. extractionwas extracted with boiling methanol until washings
10. filtrationfiltered
11. concentrationconcentrated to dryness
12. customdried overnight
13. customnearly quantitative yield), which was recrystallized from methanol