Potassium p toluenesulfinate

Hydrogen sulfide is undesirable because its presence can lead to the formation of potassium p-toluenesulfinate. The latter can be formed by the desulfurization of thiotosylate by hydrogen sulfide generated in the reaction of potassium hydrosulfide with tosyl chloride. Attention should be directed toward control of the reaction temperature so that hydrogen sulfide is rapidly removed, thereby ensuing survival of the S—S bond of the thiotosylate. p-Toluenesulfinate ion can displace bromide to form stable sulfones which are less soluble in common solvents, such as benzene, than trimethylene dithiotosylate. Therefore, purification of the dithiotosylate contaminated with the sulfones is difficult to achieve by means of fractional recrystallization. 

Potassium cyanide, 56, 20 Potassium diethyl phosphite, 58, 135, 138 Potassium 1,1,1,3,3,3-hexafluoro-2-phenyl-2 propanolate, 57, 22 Potassium iodide, 55, 71 Potassium permanganate, 55,68,58,47, 52 Potassium p-toluenesulfinate, 57, 8 /-Proline, iV-benzyloxycarbonyl-3-hy-droxy-, 56, 89... 

Gutmann680 thus obtained potassium p-toluenesulfinate by evaporating a mixture of potassium p-toluenethiosulfonate (4.5 g), potassium cyanide (2.5 g), 20% potassium hydroxide solution (2 g), and water (10 ml). 

In extension of our silver(l)-mediated synthesis of pyrroles, we have developed a catalytic version which could be realized by using a tosyl function as acceptor at the nitrogen atom. Thus, cyclization of A-tosyl-substituted homopropargylamines 12 to A -pyrrolines 13 has been achieved with catalytic amounts of the silver(l) salt. Aromatization by subsequent elimination of p-toluenesulfinic acid on treatment with potassium ferf-butoxide as base afforded the pyrroles 14 (Scheme 4) [31]. 

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