反应详情

Under argon, a solution of 11.9 g (30.7 mmol) of carboxylic acid from Example 4A in 150 ml of DMF was admixed at RT with 19.2 g (36.8 mmol) of PYBOP and 10.7 ml (61.4 mmol) of N,N′-diisopropylethylamine. Subsequently, the mixture was stirred at RT for 30 min and then the solution was added dropwise within 1.5 h to a suspension of 24.5 g (92.1 mmol) of hydroxyguanidine hemisulphate hemihydrate, 16.1 ml (92.1 mmol) of N,N′-diisopropylethylamine and 4 Å molecular sieve. The reaction mixture was stirred at RT for 1 h and then filtered through a frit. The residue was washed with 200 ml of DMF and then the combined organic phases were stirred at 130° C. (preheated oil bath) for 1.5 h. Subsequently, the solvent was removed under reduced pressure and the residue was admixed with 300 ml of diethyl ether and 300 ml of 1 N aqueous sodium hydroxide solution, and stirred vigorously for 24 h. The solid formed was filtered off, washed with water and diethyl ether and then dried under high vacuum. Yield: 8.80 g (66% of theory)

1. stirringThe reaction mixture was stirred at RT for 1 h
2. filtrationfiltered through a frit
3. washThe residue was washed with 200 ml of DMF
4. stirringthe combined organic phases were stirred at 130° C. (preheated oil bath) for 1.5 h
5. customSubsequently, the solvent was removed under reduced pressure
6. stirringstirred vigorously for 24 h
7. customThe solid formed
8. filtrationwas filtered off
9. washwashed with water and diethyl ether
10. customdried under high vacuum