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SCIENCE 



[N. S. Vol. XXX. No. 775 



of mass-action, of reactions of tlie first and 

 second order, of the development of tem- 

 perature coefficients, of Thomson's study 

 of energy changes in combustion, etc., with- 

 out the quantitative study of such organic 

 reactions as the inversion of cane sugar, 

 hydrolysis of methyl acetate, etc. 



It will, perhaps, not be uninteresting to 

 discuss some of the problems that are at 

 present occupying the attention of organic 

 chemists. The phenomena exhibited by the 

 so-called tautomeric compounds are of 

 great importance in a large number of 

 substances, such as quinazolines, cyanides, 

 sulphites, cyanates, amides, acetoacetic 

 ester, pyrazolones, uric-acid derivatives, 

 pyrimidines, all kinds of dyestuffs, such 

 as the rosanilines, phenolphthaleins, fluo- 

 resceins, etc. In 1899 we had several the- 

 ories of the action of tautomeric compounds 

 with other substances like alkyl halides and 

 acid chlorides. Those of Nef, Michael, 

 "V^Tieeler, Comstock, Knorr and Wislicenus 

 deserve special mention. 



Comstock assumed that the potassium 

 salt of an amide, for example, and an alkyl 

 halide yield only one ester, the N-ester, 

 because the potassium salt is the N-K salt 

 (see the graphic scheme below!) and that 

 the silver salt is an 0-Ag salt and yields 

 the 0-ester. Wheeler assumed that all salts 

 of amides are 0-salts and that these salts 

 yield the 0-ester primarily, which then re- 

 arranges per se, or is transformed catalytic- 

 ally by the alkyl halides into the N-ester. 

 Nef and Michael assumed that all salts are 

 0-salts and that the 0-ester is formed by a 

 direct replacement of the metal, while the 

 N-ester is formed by the primary addition 

 of the alkyl halide to the N, or to the 

 double bond between the N and the C. 

 Wislicenus and Knorr believed that iso- 

 meric esters are formed by the action of 

 alkyl halides on such so-called tautomeric 

 salts because there are present in the mole- 

 cule or ion of the salt oscillating free bonds 



or valences which can bind the entering 

 alkyl group at different positions. This 

 point of view has been used brilliantly in 

 recent years by Lapworth. 



All of these theories had much to recom- 

 mend them, and each one harmonized with 

 most of the qualitative facts known at that 

 time. Another point of view, however, 

 seemed to the speaker more plausible, 

 namely, that in some cases isomeric stable 

 esters are formed by the action of the 

 alkylating agent on two or more tautomeric 

 salts in equilibrium, in other cases the 

 esters undergo rearrangement, and in other 

 cases the anions (perhaps the molecules, 

 too) add the alkyl halide at two different 

 places. 



Now obviously a large amount of quanti- 

 tative work was an absolute necessity if we 

 were to decide which of the above several 

 theories is right. It was seen, too, that the 

 chemists who undertook to solve the prob- 

 lem would have to work for years on the 

 quantitative side before they could tell 

 their colleagues the mechanism of these 

 tautomeric reactions. 



It may be stated that quantitative work 

 in this particular field is very expensive, 

 difficult and tedious, many operations be- 

 ing necessary to give us one set of data. 

 If we had not been assisted so generously 

 by the Carnegie Institution of Washington 

 we should have made very, very slow prog- 

 ress. The investigations of the speaker and 

 of Messrs. Laist, Willcox and McRae, of 

 the University of Utah, and of Drs. Brunei, 

 Johnson, Rogers, Shadinger and Nirdlinger, 

 of this laboratory, during the past nine 

 years, on the urazoles has at last brought 

 us to the conclusion that our theory of 

 tautomeric salts is at present the best work- 

 ing hypothesis for the explanation and fur- 

 ther study of such reactions. This theory 

 has been stated^ as follows: 



' For references see Berichte der deutschen cJiein- 

 ischen Gesellschaft, 41, 3199. 



