Ethyl Acetate → 4-[4-(1,4-dioxa-8-azaspiro[4.5]dec-8-yl)phenyl]-3,4-dihydro-2H-quinoxaline-1-carboxylic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

0.31 g of 8-(4-bromophenyl)-1,4-dioxa-8-azaspiro[4.5]decane is placed in 5 ml of anhydrous o-xylene. 0.24 g of 3,4-dihydro-2H-quinoxaline-1-carboxylic acid tert-butyl ester is added, then 0.15 g of sodium tert-butoxide is added, followed by 0.009 g of palladium acetate, and then the addition is completed with 0.0084 g of tri(tert-butyl)phosphine. The reaction mixture is heated at 150° C. for 4 h, then the heating is halted and the mixture is brought back to ambient temperature. Ethyl acetate is added and the mixture is washed twice with water and then twice with a saturated aqueous sodium chloride solution. The organic phase is dried over sodium sulphate and concentrated under reduced pressure. The crude product obtained is chromatographed on silica gel, elution being carried out with a heptane/ethyl acetate (4/1) solvent mixture. 0.27 g of 4-[4-(1,4-dioxa-8-azaspiro[4.5]dec-8-yl)phenyl]-3,4-dihydro-2H-quinoxaline-1-carboxylic acid tert-butyl ester is obtained.

Provenance & Evidence