Sulfonic acid chlorides

As to arylisoxazoles, it was only in 1961 that Woodward et investigated the sulfonation of 5-phenylisoxazole. In contrast to nitration, only the phenyl nucleus is sulfonated to yield a mixture of m- and p-aryl sulfonic acid chlorides (62) in a 2 1 ratio. 

Dimethyl-5-aminoisoxazole p-Acetaminobenzene sulfonic acid chloride Hydrogen chloride... 

Electrofluorination of aliphatic carboxylic and sulfonic acid chlorides or fluorides to perfluorinated products [31]. 

Similar good results were obtained with Fe3+ montmorillonite and zeolite Beta with sulfonic acids, chlorides, or anhydrides as reagents.278 Iron(III) chloride is also very effective in this reaction under microwave irradiation.279 Sulfonylation by sulfonic acids catalyzed by Nafion-H allows the synthesis of both symmetric and unsymmetric sulfones.280... 

C.I. Acid Yellow 76, 18850 [6359-88-2] (14), is obtained by coupling diazotized 4-aminophenol onto the pyrazolone component and then esterifying with -toluene-sulfonic acid chloride in an alkaline medium. The toluenesulfonic ester group substantially improves the fastness to milling and makes the shade obtained largely independent of pH the lightfastness is not quite as good as that of C.I. Acid Yellow 17. 

Activation of Carboxylic Acids with Sulfonic Acid Chlorides... 

Via the in situ activation, applying sulfonic acid chlorides, covalent binding of bioactive molecules onto dextran was achieved by esterification of the polymer with a-naphthylacetic acid (1), nicotinic acid (2) and naproxen (3) homogeneously in DMF/LiCl using p-toluenesulfonyl chloride (tosyl chloride, TosCl) or methanesulfonic acid chloride (mesyl chloride, MesCl) and pyridine within 22 h at 30-70 °C (Fig. 22). 

Both the temperature and the concentration of pyridine as well as the type of sulfonic acid chloride show an influence on the reaction, as displayed in Table 8 [180]. The esterification is even possible without the base. 

Table 8 Influence of the concentration of pyridine [Py], the reaction temperature, and type of sulfonic acid chloride applied for the esterification of dextran (0.12 mol L 1) in DMF/LiCl with a-naphthylacetic acid (0.37 mol L-1) for 22 h...

Conditions [Py] (mol L 1) Temp. (°C) Sulfonic acid chloride Product DS... 

Pyrimido[5,4-6][ 1,4]oxazine-4,7-diones (175) can be transformed to 4-monosulfonic esters (176) by treatment with sulfonic acid chlorides (Equation (26)) <89MIP47293>. 

Carboxylic and sulfonic acid chlorides and anhydrides give acylamino- and sulfonamidopyridines 748 and 749. Evidence exists that initial products of the reaction, the corresponding A -acyl-2-aminopyridinium salts, are unstable and rapidly rearrange to the thermodynamically more stable 2-acylaminoderivatives. 

SulfocUorination (similar to the photochemical reaction by UV), e.g. production of 10 sulfonic acid chlorides by irradiation of mixtures of carbohydrates, SO2 and CI2 Production of alkylsulfonic acids by irradiation of mixtures of carbohydrates, SO2 lO -lO ... 

Activation with sulfonic acid chlorides is more general, rendering amides with the possible participation of symmetric anhydrides after disproportionation. This method has also found use in the synthesis of modem 3-lactam antibiotics. However, in peptide chemistry this activation method leads to unwanted side reactions, like formation of nitriles in the cases of glutamine and asparagine, and racemization. In a convenient one-pot procedure, the carboxylic acids are activated by sulfonyl chlorides under solid-liquid phase transfer conditions using solid potassium carbonate as base and a lipophilic ammonium salt as catalyst. ... 

Oxo-3-pyrazolin-4-sulfonic acids (Table XXXVI) are prepared by direct sulfonation738,745 with sulfuric acid and acetic anhydride or by chlorosulfonation with chlorosulfonic acid, followed by hydrolysis to the acid.1248,1249 The reaction of 2,3-dimethyl-l-phenyl-5-oxo-3-pyrazolin-4-sulfonyl chloride with urea forms a bis(5-oxo-2-pyrazolin-4-sulfonic acid) derivative,1249 the only such bis derivative reported. Reduction of the sulfonic acid chlorides with zinc and acid forms the corresponding mercapto compound.1249... 

Sulfinic acids from sulfonic acid chlorides... 

Sulfonic acid amides from thioethers via sulfonic acid chlorides s. 3, 420 SR -y S02NHs... 

Sulfonic acid chlorides from thiocyanates s. 1,118 SON —S02C1... 

Sulfones from sulfonic acid chlorides Ar-SOgCl —Ar-SOs-Ar ... 

Mercaptans from sulfonic acid chlorides so2Cl —> SH s. 3, 30 in glacial acetic acid s. E. Kniisli, G. 79, 621 (1949) ... 

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