Reaktion #475458

Reaktionsgleichung

(±)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl

sodium-tert-butoxide

8-bromo-6-chloro-2,3-dihydro-benzo[1,4]oxazine-4-carboxylic acid benzyl ester

piperazine-1-carboxylic acid tert-butyl ester

→

8-(4-tert-butoxycarbonyl-piperazin-1-yl)-6-chloro-2,3-dihydro-benzo[1,4]oxazine-4-carboxylic acid benzyl ester

Lösungsmittel

ethyl acetate

toluene

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeflushed with nitrogen
2. 2
   TemperaturThe mixture was cooled to room temperature
3. 3
   Filtrationfiltered through celite
4. 4
   Einengenconcentrated
5. 5
   SonstigeThe crude material was purified by flash chromatography on silica gel (
6. 6
   Wascheneluting with hexane-ethyl acetate

Vorschrift

A three neck flask was charge with tris(dibenzylideneacetone)dipalladium(0) (21.5 mg, 0.024 mmol, 2 mol % Pd), (±)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (36.4 mg, 0.059 mmol, 5 mol %) and sodium-tert-butoxide (159 mg, 1.65 mmol) and flushed with nitrogen. A solution of 8-bromo-6-chloro-2,3-dihydro-benzo[1,4]oxazine-4-carboxylic acid benzyl ester (450 mmg, 1.18 mmol) and piperazine-1-carboxylic acid tert-butyl ester (263 mg, 1.41 mmol) in toluene (2 mL) was added. The mixture was heated to 95° C. and was stirred for 12 hours. The mixture was cooled to room temperature, taken up in ethyl acetate, filtered through celite and concentrated. The crude material was purified by flash chromatography on silica gel (eluting with hexane-ethyl acetate; 7:3, v/v) to give 8-(4-tert-butoxycarbonyl-piperazin-1-yl)-6-chloro-2,3-dihydro-benzo[1,4]oxazine-4-carboxylic acid benzyl ester a colorless oil (275 mg, 48%). MS: MH+=488.

Quelle