Synonyms: Butanoicacid, 2-methyl-, anhydride, (2S,2'S)- (9CI); Butanoic acid, 2-methyl-,anhydride, [S-(R*,R*)]-; (+)-(S)-2-Ethylpropionic anhydride;(+)-2-Ethylpropionic anhydride; (S)-(+)-2-Methylbutyric anhydride;(S)-2-Ethylpropionic anhydride; (S)-2-Methylbutanoic anhydride;(S)-2-Methylbutyric anhydride