Starting from ten selected a values, a large number of @ values is calculated; these p values in their turn serve to calculate other a values. The results prove that the concept of "duality of (I constants" is erroneous. In those cases in which a substituent enters into mesomeric para interaction with the reaction centre, a multiplicity of (exalted) a values is observed:this holds for + M as well as for -M substituents. In the absence of mesomeric para interaction a values are reasonably constant; the mean of such (I values ( 0 " ) is listed.It is demonstrated that a values are, in general, not suitable for judging mesomeric para interactions, and should be replaced by the (free) energy difference term --ddF,=p(a-d') X2.303RT. involving not only the exaltation of u, but p and T as well. Several important applications of this concept are discussed, illustrating the way in which the pa relationship can be most profitably used for mechanistic and predictive purposes. A. Introduction.One of the most successful attempts to correlate rate and equilibrium constants in a quantitative way is the well-known Harnrnett equation's':where k is a rate or equilibrium constant, in the original meaning pertaining only to the side-chain reactivity of a rneta-or para-substituted benzene derivative; k" is the rate or equilibrium constant for the corresponding unsubstituted compound: c, the reaction constant, is a constant specific for the side-chain reaction under consideration; 0 , the substituent constant, is a constant pertaining to the substituent. log k-log k" = @a, 1 L. P. Hammetf, Physical Organic Chemistry (McGraw-Hill Book Company. Inc., New-York). 1940. H. H. /a&, Chem. Revs. 53, 191 (1953. 816H . van Bekkurn, P . E. Verkade, and B. M . Wepsfer, For practical reasons, Harnrnett took as unity for the dissociation constants of benzoic acids in water at 2 5 O , so that "primary" rnefa-and para-a constants could be defined as the difference between the logarithms of the dissociation constant of a substituted benzoic acid and of benzoic acid itself. Starting from these primary u constants, additional a constants were derived with the aid of data relating to other reactions.Obviously, the u constants ought to have general applicability. However, it was noted by Harnrnett that with reactions of phenols and anilines and their derivatives the para-nitro substituent required a special exalted (J constant, u = 1.27, widely different from the normal one, u = 0.778, which had been found applicable to the other reactions investigated. This "duality of u constants" was considered possibly to hold generally for rneta-directing substituents (COOH, CHO, CN, etc.) in para position.The "duality of constants" has been generally assumed to arise from mesomeric para interactions as indicated for the case of paranitroaniline by I or by the limiting structure 11. Since this type of para I I I interaction does not occur, or is insignificant, in para-nitrobenzoic acid, the normal u constant for the para-nitro group does not reflect this facto...

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1) IT was shown in the first paper of this series [Verkade et al., 1933] that with two healthy subjects (V. and v. d. L.) considerable quantities of undecanedioic acid were excreted in the urine after administration of triundecylin. In the human organism the terminal methyl group of the undecoic acid, the component acid of triundecylin, is thus oxidised-and as we shall see later, very readily-to a carboxyl group. The term c-oxidation was introduced by us for this type of oxidation CH3. (CH2)9. COOH 0 HOOC. (CH2)9.COOH.The present communication deals with the question whether the administration of chemically pure simple triglycerides of other, higher and lower, odd and even saturated fatty acids leads similarly to the excretion of the corresponding dicarboxylic acids and if so, to what extent.

Some new quinazoline derivatives were prepared by boiling the appropriate ortho-c yano-acylaminobenzene in alkaline alcoholic medium. Proofs of the constitution of the quinazoline derivatives are given.In a previous paper under the same title Breukink, Krol, Verkade, and Wepster 1 described the preparation of 4-RO-substituted quinazolines of the general type I11 (R and R' being hydrocarbon radicals) by boiling the corresponding ortho-cyano-acylamino compounds I in the appropriate alkaline alcoholic or phenolic medium (R'OH). A compound of type I1 was assumed as intermediate in this synthesis; this assumption was undoubtedly based on reasonable grounds 2.

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