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Feb., 1037
C 0 M M U N I C AT1 0 NS T O T H E EDITOR BENZANTHRONE AND 4-PHENYLBENZANTHRONE
racemic product. The reaction under discussion does not involve a substitution by ions, and espeIn a recent elaboration of their former work, cially not by negative ions; it reminds one of the Charrier and Ghigi [Ber., 69, 2211 (1936)l have ‘well-known observation of Senter and co-workers suggested that in our study of Grignard addition [J. Chem. Soc., 107,638 (1915); 109, 1091 (1916); to benzanthrone [THISJOURNAL, 57, 740 (1935)l 117, 140, 151 (1918)] that I-phenylchloroacetic we failed to concede priority to them. We regret acid by interaction with ammonia in water or althat our mode of presentation failed to make clear cohol gives d-, in acetonitrile or liquid ammonia that the Italian workers first proved two instances 1-phenylaminoacetic acid, or the experiments of of 1,4-addition of the Grignard reagent to benzan- Holmberg [Ber.,60, 2194, 2198 (192711 on the rethrone and predicted the structure of 4-phenyl- lationship between the rotation of xanthogenosuccinic acid and the temperature at which it was benzanthrone. C. F. H. ALLEN prepared from active bromosuccinic acid. The MCGILLUNXVERSJTY MONTREAL, CANADA S . C. OVERBAUGHtheory of Bergmann, Polanyi and Szabo does not RECEWED JANUARY 8, 1937 make any prediction for such cases. It may be added that in the group of these octahedral complexes some substitutions by negaWALDEN INVERSION IN SUBSTITUTIOI REACTIONS ON INORGANIC COMPLEX COMPOUNDS tive ions are already known to be accompanied by configurational inversion. Without discussing Sir: Recently Bailar, Haslam and Jones [THIS the whole existing material, reference may be JOURNAL, 58, 2226 (1936)l have published an in- made to the following two reactions: (a) cisteresting paper on the steric course of the sub- Chloro isorhodanato diethylenediamino - cobaltic stitution reaction between Z-dichloro-diethylene- ion is converted by means of rhodanide ions into diamino-cobaltichloride and 2 moles of ammonia trans - diisorhodanato - diethylenediamino - cobaltic which leads to a lato-product a t low, to a dextro- ion [A. Werner, Ann., 386, 1 (1912)]. (b) transproduct at high, temperature. Since the theo- Chloro - isorhodanato - diethylenediamino - cobaltic retical considerations about Walden inversion on salts are converted by hydroxide ions (aqueous which the paper is based are likely to be misunder- ammonia solution) into cis-hydroxoisorhodanatostood, I would like to draw attention to the follow- diethylenediamino-cobaltic salts. Likewise, the ing point. According to the authors, Bergmann, auto-racemization observed in some of the inorPolanyi and Szabo [Z. physik. Chem., ZOB, 161 ganic complex compounds may be due to the same 32, 843 (1936)l in mechanism as the racemization of (1933); Trans. Faraday SOC., CH-Hal by b a> their theory of Walden inversion predict that each reaction involving a single step in substitution on halogenide ions, e. g., the autoracemization of dichloride to the the tetrahedral carbon atom will bring about in- chloro-diethylenediamino-cobaltic version, an even number of substitutions there- substitution of the inner chloro atoms by negative fore reproducing the original configuration. In chloride ions. [Werner, Ber., 44,3279 (1911); 45, the above case, this apparently is not always the 3294 (1912)) suggested that the racemization is fact. As a matter of fact, Bergmann, Polanyi caused by aquation, but this has never been and Szabo are concerned expressly with substitu- proved by isolation of a chloroaquo-diethylenetions of polar bonds by ions;‘ they assert that diamino-cobaltic salt.] Of course, we cannot presubstitution of such a polar bond by a negative dict whether all the known cases fit into our simion is necessarily connected with configurational ple scheme, but we hope to come to some definite inversion, while substitution by a positive ion conclusions in the course of our further investigaleads either to the initial configuration or to a tions on Walden inversion.
Sir:
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(1) I t may be added that the afore-mentioned inorganic complex salt has an octahedral, not 8 tetrahedral, structure, but the theory should really be extendable to this case.
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THEDANIELSIEFFRESEARCH INSTITUTE REHOVOTH, PALESTINE ERNST BERGMANN RECEIVBD DECEMBER 30,1936
