Stereoisomeric Chlorimido Acid Esters

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: Stereoisomeric Chlorimido Acid Esters In 1890 Hantzsch and Werner1 announced their theory that the stereoisomerism of the benzilmonoximes and di- oximes, proved by V. Meyer2 and his collaborators, and of the aldoximes, proved by Goldschmidt,3 is caused by the stereochemical properties of the nitrogen...
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Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: Stereoisomeric Chlorimido Acid Esters In 1890 Hantzsch and Werner1 announced their theory that the stereoisomerism of the benzilmonoximes and di- oximes, proved by V. Meyer2 and his collaborators, and of the aldoximes, proved by Goldschmidt,3 is caused by the stereochemical properties of the nitrogen present in these substances. Their ideas extended the theory of van't Hoff and Wislicenus, regarding carbon, to nitrogen. They rest upon the assumption that in certain nitrogen derivatives the three valences of the nitrogen atom are directed towards three corners of an irregular tetrahedron, the fourth corner of which is occupied by the nitrogen atom itself. This assumption led directly to the conclusion that the cis-trans stereoisomerism of ethylene derivatives (XHC = CHX) might also occur in certain cases when a double bond exists between nitrogen atoms or between a carbon and a nitrogen atom, as in the case of oximes of the type R ? C ? R' R ? C ? R' ]] and ]] N ?X X ?N. Hantzsch and Werner's theory has proved remarkably fruitful and reliable in explaining the occurrence of stereoisomerism among such derivatives as the oximes, the hy- drazones, and diazo bodies, and must be considered as firmly established. If there has been any criticism at all attaching to the theory, it has lain in the unusually large proportion of negative results incidental to efforts to vary the radical X in the above type from the form which it has in the oximes (X = OH; OR'; O ? acyl) and hydrazones (X = NHC6H5; NRC6H5; N ? acyl ? oH6). We possibly have some Stereoisomeric phenylimide derivatives, but the occurrence of such stereoisomers as claimed 1 Her. d. cbem. Gcs., 23, 11, 1243 (1890). Ibid.. 18, 503, 1616. 2176 (1883), 'Ibid., 22, 3113 (1889), 19794T by Schall1 for modif...