Chlorosulfonic acid precursor

Due to the abundance of epoxides, they are ideal precursors for the preparation of P-amino alcohols. In one case, ring-opening of 2-methyl-oxirane (18) with methylamine resulted in l-methylamino-propan-2-ol (19), which was transformed to 1,2-dimethyl-aziridine (20) in 30-35% yield using the Wenker protocol. Interestingly, l-amino-3-buten-2-ol sulfate ester (23) was prepared from l-amino-3-buten-2-ol (22, a product of ammonia ring-opening of vinyl epoxide 21) and chlorosulfonic acid. Treatment of sulfate ester 23 with NaOH then led to aziridine 24. ... 

No research work about the post-sulfonation of a naphthalenic structure has yet been reported and only few examples of the post-sulfonation of a phthalic polyimide are mentioned in the literature [45,46]. Both mentioned articles are concerned with the sulfonation of the polyimide synthesized from bis[4-(3-aminophenoxy)phenyl]sulfone and PMDA, either in the presence of chlorosulfonic acid (CISO3H) or sulfur trioxide-triethyl phosphate (2SO3 TEP) (Fig. 1). Because of the very low solubihty of the polyimide precursor, the post-sulfonation is performed in heterogeneous conditions. 

Structural variation of perylenes can simply be accomplished by using different amine precursors. The chemical structures of various photoconductive perylenes (general structures XIX and XX) are shown in Table 10.8. Another approach is to modify the central perylene ring structure. Along this line, Duff et al. [238] showed that sulfonation of perylene-3,4,9,10-tetracarboxylic dianhydride with chlorosulfonic acid leads to the formation of perylene-l,12-sulfone-... 

As mentioned above, the bis-amides 9a are used as precursors in the synthesis of Af-acylenamines. The conditions used for this reaction depend on the purpose of the synthesis and are described in numerous works, and reviewed in a series of articles35-37. The acid catalyst is usually concentrated sulfuric acid, but a successful application of 85% phosphoric, chlorosulfonic, methanesulfonic and formic acids was reported, and reactions were also conducted in the presence of anhydrous hydrogen chloride35. The solvents used are usually glacial acetic acid and chlorinated hydrocarbons. It is believed that the water necessary for the formation of the bis-amides under anhydrous conditions is obtained from conversion of the carboxylic acid to the anhydride, or even the sulfuric acid35. 

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