Saccharin pseudochloride

Two new pyridone derivatives (14) and (15) have been prepared by cycloaddition of saccharin pseudochloride (16 R = Cl) with Danishefsky s diene and by treatment of (16 R = Me) with ciimamoyl chloride. The synthesis of two more ting expanded derivatives (17) and (18) via cycloaddition to benzisothiazoles was also described <96T3339>. 

Saccharin pseudochloride 112 (R = C1) reacts with 1-diethylamino-l-propyne to give 113. When the corresponding 3-ethoxy derivative 112 (R = OEt) was treated with the same alkyne, a ring-expansion product 114 (R = OEt) was isolated. On the other hand, the analogous thiazepine 114 (R = OSiMc3) is obtained, together with the ketone derived by hydrolysis of the silyl enol ether, by the reaction of saccharin with BuLi/trimethylsilyl chloride (TMCS)... 

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See also in sourсe #XX -- [ ]

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