Acetic Acid → HCID 59142065, compound

Participants

Reaction Conditions

Reaction Steps

0.52 mol of (S)-2,5-dihydro-3,6-dimethoxy-2-isopropyl pyrazine are solved in 400 ml of absolute THF under argon and are cooled to −78° C. Under stirring, 200 ml of a 2.7 M solution of butyl lithium (in heptane) (0.54 mol) are added in drops and slowly. Subsequently, a solution of 0.52 mol diethyl-(2-bromethyl) phosphonate in 300 ml of absolute THF is added in drops and slowly during stirring, and the mixture is stirred for further 3 h at −78° C. Then, 11.7 ml (about 0.2 mol) anhydrous acetic acid are added slowly. The reaction mixture is allowed to warm up slowly to room temperature. The solvent is removed, and the residue is solved in 600 ml of diethyl ether and washed with 200 ml of water. The aqueous phase is still extracted three times with each 100 ml of diethyl ether. The combined ether phases are dried over MgSO4, filtered and the solvent is removed in vacuo. The residue is solved in a mixture of diethyl ether and hexane (1:10) and filtered over a bed of silica gel. Thereafter, the non reacted educt is eluted with diethyl ether and hexane (1:5). Finally, the product is eluted with acetic acid ethyl ester.

Provenance & Evidence