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- Title
Zur Synthese sulfonierter Derivate von 4-Amino-1,3-dimethylbenzol und 2-Amino-1,3-dimethylbenzol.
- Authors
Courtin, Alfred; Tobel, Hans-Rudolf Von; Doswald, Paul
- Abstract
Syntheses of Sulfonated Derivatives of 4-Amino-1, 3-dimethylbenzene and 2-Amino-1, 3-dimethylbenzene Direct sulfonation of 4-amino-1, 3-dimethylbenzene (1) and sulfonation of 4-nitro-1,3-dimethylbenzene ( 4) to 4-nitro-1,3-dimethylbenzene-6-sulfonic acid ( 3) followed by reduction yield 4-amino-1,3-dimethylbenzene-6-sulfonic acid ( 2). The isomeric 5-sulfonic acid ( 5) however is prepared solely by baking the acid sulfate salt of 1. Reaction of sulfur dioxide with the diazonium chloride derived from 2-amino-4-nitro-1,3-dimethylbenzene ( 7) leads to 4-nitro-1,3-dimethylbenzene-2-sulfonyl chloride ( 8), which is successively hydrolyzed to 4-nitro-1,3-dimethylbenzene-2-sulfonic acid ( 9) and reduced to 4-amino-1, 3-dimethylbenzene-2-sulfonic acid ( 6). Treatment of 4-amino-6-bromo-1,3-dimethylbenzene ( 12) and 4-amino-6-chloro-1, 3-dimethylbenzene ( 13), the former obtained by reduction of 4-chloro-6-nitro-1,3-dimethyl-benzene ( 10) and the latter from 4-chloro-6-nitro-1, 3-dimethylbenzene ( 11), with oleum yield 4-amino-6-bromo-1,3-dimethylbenzene-2-sulfonic acid ( 14) and 4-amino-6-chloro-1,3-dimethylbenzene-2-sulfonic acid ( 15) respectively; subsequent carbon-halogen hydrogenolyses of 14 and 15 lead also to 6 ( Scheme 1). Baking the acid sulfate salt of 2-amino-1, 3-dimethylbenzene ( 17) gives 2-amino-1, 3-dimethylbenzene-5-sulfonic acid ( 16), whereas the isomeric 4-sulfonic acid ( 18) can be prepared by either of the following three possible pathways: Sulfonation of 2-nitro-1,3-dimethylbenzene ( 20) to 2-nitro-1,3-dimethylbenzene-4-sulfonic acid ( 21) followed by reduction or sulfonation of 2-acetylamino-1,3-dimethylbenzene ( 19) to 2-acetylamino-1,3-dimethylbenzene-4-sulfonic acid ( 22) with subsequent hydrolysis or direct sulfonation of 17. Further sulfonation of 18 yields 2-amino 1,3-dimethylbenzene-4,6-disulfonic acid ( 23), the structure of which is independently confirmed by reduction of unequivocally prepared 2-nitro- 1,:3-dimethylbenzene-4,6-disulfonic acid ( 24)(Scheme 2).
- Publication
Helvetica Chimica Acta, 1978, Vol 61, Issue 8, p3079
- ISSN
0018-019X
- Publication type
Article
- DOI
10.1002/hlca.19780610834