STUDIES OF THE ZIMMERMANN REACTION: FACTORS AFFECTING THE COLOR INTENSITY; RELATION OF MOLECULAR STRUCTURE TO COLOR PRODUCTION1,2

Abstract

Studies were made on the relation of heating time, conc. of m-dinitrobenzene, and conc. of aqueous KOH to the production of color with the Zimmermann technique for 17 ketosteroids, employing androsterone and dehydroisoandrosterone, and using the Evelyn photoelectric colorimeter for colorimetry. Optimum results were obtained with a heating period of 60 min. at 25[degree]C, 2% m-dinitrobenzene, and 5-6 [image] KOH. Androsterone and dehydroisoandrosterone were tested with aqueous KOH, varying in conc. from 1 to 8 [image], and measuring with Rubicon filters 420, 490, 520, 540, 580, 600, 620, 635, and 660. The numbers indicate the approx. mean wave-length of the transmitted band in mu. Absorption increased with increase in cone, of KOH, but opt. conditions for practical use are obtained with 5-6 [image] KOH and with filter 520. Absorption values of the 2 substances are practically identical with the higher concs. of KOH, but with decrease in conc. of KOH the difference in absorption increases. 14 steroids and acetone were tested under opt. conditions as above indicated, and absorption was measured with Rubicon filters as previously stated. The observations were made with reference to a) the absorption constant for each substance, b) the value of these constants in terms of androsterone equivalents, c) the variation of the color as related to the molecular structure of these substances, and d) the general importance of the color produced from the quantitative standpoint in Zimmermann techniques for the assay of 17 ketosteroids.