1-Piperazinepropionic acid, 4-methyl-, alpha-ester with 2,2-dichloro-N-(beta-hydroxy-alpha-(hydroxymethyl)-p-nitrophenethyl)acetamide, dihydrochloride 89170-55-8 Chloramphenicol 4-methyl-1-piperazinepropionate dihydrochloride hydrate M.G. 7024