2-dehydro-D-erythronate <=> 3-dehydro-D-erythronate
2-dehydro-d-erythronate <=> 3-dehydro-d-erythronate
2-dehydro-D-erythronate <=> 3-dehydro-D-erythronate
2-dehydro-d-erythronate <=> 3-dehydro-d-erythronate