Improved methods are given for the preparation of 5-nitro- and 5-amino-dihydro-quinine, and it is shown that under the usual conditions of nitration with nitric and sulfuric acids sulfonation also occurs, and 5-nitro-dihydro-quinine sulfonic acid is formed as a by-product. The extension of the methods of nitration and reduction to ethyl-dihydrocupreine (optochin), dihydro-quinidine and ethyl-dihydro-cupreidine led to the formation of the nitro and amino derivatives of these alkaloids, and descriptions of these new substances are given. 5-Nitro-dihydro-quinane (see next paper) is also described. © 1920, American Chemical Society. All rights reserved.