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  • 1
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Syntheses of Sulfonated Derivatives of 4-Amino-1, 3-dimethylbenzene and 2-Amino-1, 3-dimethylbenzeneDirect 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).
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the Synthesis of Sulfonated Derivatives of 2,3-Dimethylaniline and 3,4-DimethylanilineBaking the hydrogensulfate salt of 2,3-dimethylaniline (1) or of 3,4-dimethylaniline (2) led to 4-amino-2,3-dimethylbenzenesulfonic acid (4) and 2-amino-4,5-dimethylbenzenesulfonic acid (5), respectively (Scheme 1). The sulfonic acid 5 was also obtained by treatment of 2 with sulfuric acid or by reaction of 2 with amidosulfuric acid. 3-Amino-4,5-dimethylbenzenesulfonic acid (3) and 5-Amino-2,3-dimethylbenzenesulfonic acid (6) were prepared by sulfonation of 1,2-dimethyl-3-nitrobenzene (9) to 3,4-dimethyl-5-nitrobenzenesulfonic acid (11) and of 1,2-dimethyl-4-nitrobenzene (10) to 2,3-dimethyl-5-nitrobenzenesulfonic acid (12), respectively, with subsequent Béchamp reduction (Scheme 1). Preparations of 2-amino-3,4-dimethylbenzenesulfonic acid (7) and of 6-amino-2,3-dimethylbenzenesulfonic acid (8) were achieved by the sulfur dioxide treatment of the diazonium chlorides derived from 3,4-dimethyl-2-nitroaniline (24) and from 2,3-dimethyl-6-nitroaniline (31) to 3,4-dimethyl-2-nitrobenzenesulfonyl chloride (29) and 2,3-dimethyl-6-nitrobenzenesulfonyl chloride (32), respectively, followed by hydrolysis to 3,4-dimethyl-2-nitrobenzenesulfonic acid (30) and 2,3-dimethyl-6-nitrobenzenesulfonic acid (33), and final reduction (Scheme 3). Compound 7 was also synthesized by reaction of 4-chloro-2,3-dimethylaniline (23) with amidosulfuric acid to 2-amino-5-chloro-3,4-dimethylbenzenesulfonic acid (20) and subsequent hydrogenolysis (Scheme 2). 4′-Bromo-2′, 3′-dimethyl-acetanilide (13) and 4′-chloro-2′, 3′-dimethyl-acetanilide (14) on treatment with oleum yielded 5-acetylamino-2-bromo-3,4-dimethylbenzenesulfonic acid (17) and 5-acetylamino-2-chloro-3,4-dimethylbenzenesulfonic acid (18), respectively. Their structures were proven by hydrolysis to 5-amino-2-bromo-3,4-dimethylbenzenesulfonic acid (21) and 5-amino-2-chloro-3,4-dimethylbenzenesulfonic acid (22), followed by reductive dehalogenation to 3.
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