Reaktion #11051

Reaktionsgleichung

Benzyl alcohol

carboxylic acid

(S)-6-(tert-butoxycarbonyl)-4-oxo-4,6,7,8-tetrahydropyrrolo[1,2-a]pyrimidine-3-carboxylic acid

triethylamine

DPPA

→

benzyl carbamate

Ausbeute 73.0%

tert-butyl (S)-3-{[(benzyloxy)carbonyl]amino}-4-oxo-4,6,7,8-tetrahydropyrrolo[1,2-a]pyrimidine-6-carboxylate

Ausbeute 73.0%

Lösungsmittel

1,4-dioxane

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturat reflux for 2 h
2. 2
   Temperaturthe mixture was heated
3. 3
   Temperaturat reflux for an additional 3 h
4. 4
   EinengenThe mixture was concentrated in vacuo
5. 5
   Sonstigethe oil obtained
6. 6
   Sonstigewas purified by flash chromatography (50 to 100% EtOAc/hexanes)

Vorschrift

A solution of carboxylic acid 1f (11.4 g, 40.7 mmol), triethylamine (5.67 mL, 40.7 mmol), and DPPA (8.86 mL, 40.7 mmol) in 180 mL 1,4-dioxane was heated at reflux for 2 h. Benzyl alcohol (4.67 mL, 45 mmol) was added and the mixture was heated at reflux for an additional 3 h. The mixture was concentrated in vacuo and the oil obtained was purified by flash chromatography (50 to 100% EtOAc/hexanes) to provide 11.13 g (73%) of the benzyl carbamate (1 g) as a tan solid. 1H NMR (300 MHz, CDCl3) δ 8.67 (br s, 1H), 7.39–7.34 (m, 5H), 5.21 (s, 2H), 4.98 (dd, J=9.6, 3.0, 1H), 3.23–2.98 (m, 2H), 2.63–2.49 (m, 1H), 2.37–2.23 (m, 1H), 1.48 (s, 9H).

Quelle