Réaction #63633

Équation de réaction

N-cyclopentyl-N-(3-mercapto-2-methylpropanoyl)glycine

2,2'-dipyridyldisulfide

triphenylphosphine

→

4-Cyclopentyl-6,7-dihydro-6-methyl-1,4-thiazepin-2,5-(3H,4H)-dione

Solvants

toluene

toluene

toluene

Conditions de réaction

Traitement

1. 1
   Autreby bubbling nitrogen through it
2. 2
   Températureat reflux for 48 hours
3. 3
   LavageThe solution was washed successively with 0.1N hydrochloric acid saturated sodium bicarbonate, water and brine
4. 4
   Séchagedried over anhydrous magnesium sulfate
5. 5
   Filtrationfiltered
6. 6
   Concentrationconcentrated under vacuum
7. 7
   workup.DISSOLUTIONThe resulting solid material was dissolved in 25% ethyl acetate/hexane
8. 8
   Filtrationfiltered
9. 9
   Autreto remove the triphenyl phosphine oxide which
10. 10
    Autrecrystallized
11. 11
    Autrepurified by medium pressure liquid chromatography
12. 12
    Lavageeluting with 25% ethyl acetate/hexane
13. 13
    Autreto give 0.8 g
14. 14
    AutreThis solid was recrystallized from 10% ethyl acetate/hexane
15. 15
    Autreto give 0.5 g (27%) of 4-cyclopentyl-6,7-dihydro-6-methyl-1,4-thiazapen-2,5-(3H,4H)-dione as a white crystalline solid, mp. 77°-79°

Mode opératoire

A solution of N-cyclopentyl-N-(3-mercapto-2-methylpropanoyl)glycine (2.0 g., 8.1 mmol) in 125 ml of toluene was freed of air by bubbling nitrogen through it. To this solution was then added 2,2'-dipyridyldisulfide (2.7 g., 12.2 mmol) and triphenylphosphine (3.2 g., 12.2 mmol) and the resulting solution was stirred under nitrogen for 5 hours. This solution was then diluted to 250 ml with toluene and added at a rate of 20-25 ml/hr to 2 l of reluxing toluene under nitrogen. The resulting mixture was stirred at reflux for 48 hours and then cooled to room temperature. The solution was washed successively with 0.1N hydrochloric acid saturated sodium bicarbonate, water and brine, dried over anhydrous magnesium sulfate, and then filtered and concentrated under vacuum. The resulting solid material was dissolved in 25% ethyl acetate/hexane, filtered to remove the triphenyl phosphine oxide which crystallized, and purified by medium pressure liquid chromatography, eluting with 25% ethyl acetate/hexane, to give 0.8 g. of a pale yellow solid. This solid was recrystallized from 10% ethyl acetate/hexane to give 0.5 g (27%) of 4-cyclopentyl-6,7-dihydro-6-methyl-1,4-thiazapen-2,5-(3H,4H)-dione as a white crystalline solid, mp. 77°-79°.

Source