Acetic acid, 2-(triphenylphosphoranylidene)-, ethyl ester → HCID 10854265, compound

Participants

Reaction Conditions

Reaction Steps

Into the 6-(tert-butyloxycarbonylamino)chroman-2-ol toluene solution of Example 2 (8 L) was added 1225 g of (carbethoxymethylene)triphenylphosphorane (95%) and 1.1 g of sodium ethoxide. The stirred reaction was heated to 80° C. for 2 h. An additional 3.2 g of sodium ethoxide was added, and the mixture stirred at 80° C. for 18 h. Because the reaction was not complete by TLC, an additional 122 g of (carbethoxymethylene)triphenylphosphorane and 1.0 g of sodium ethoxide was added. The reaction mixture was stirred at 80° C. for 3 h after the addition. The reaction was cooled to room temperature, and 3750 g of silica gel and 7 L of toluene were added. The mixture was stirred for 2 h, filtered, and the filter cake was washed with 2×12 L of toluene. The filtrate and washings were combined, and the volume reduced to about 7 L by distillation under reduced pressure (T≦60° C.) to provide a toluene solution of ethyl 2-(6-(tert-butyloxycarbonylamino)chroman-2-yl)acetate.

Provenance & Evidence