反应详情

Scheme 4 shows the synthesis of intermediate (S)-2-hydroxy-1-(piperazin-1-yl)propan-1-one V from (S)-ethyl 2-hydroxypropanoate 7. 1-Benzylpiperazine and 7 were reacted in sodium methoxide and methanol to give (S)-1-(4-benzylpiperazin-1-yl)-2-hydroxypropan-1-one 8, isolated from AMBERLITE® IRC-748 resin or oxalic acid, followed by the activated charcoal treatment (Example 10). Reductive cleavage removal of the benzyl group from 8 was effected by palladium catalysis with either hydrogen gas (Method A) or cyclohexene (Method B) to give intermediate (S)-2-hydroxy-1-(piperazin-1-yl)propan-1-one 6 (Example 11). The oxalate salt was formed from 6 with oxalic acid in ethanol and tetrahydrofuran to give V (Example 11).