(2S)-2-isopropylmalate => (2R,3S)-3-isopropylmalate
(2s)-2-isopropylmalate => (2r,3s)-3-isopropylmalate
(2S)-2-isopropylmalate => (2R,3S)-3-isopropylmalate
(2s)-2-isopropylmalate => (2r,3s)-3-isopropylmalate