2-dehydro-L-erythronate => 3-dehydro-L-erythronate
2-dehydro-l-erythronate => 3-dehydro-l-erythronate
2-dehydro-L-erythronate => 3-dehydro-L-erythronate
2-dehydro-l-erythronate => 3-dehydro-l-erythronate