Isothiazole 5- nitro

On treatment with mercuric acetate in aqueous acetic acid at 100°, isothiazole gives a 48% yield of a dimercuriacetate, which with bromine affords 4,5-dibromoisothiazole. Unlike lithiation, a nitro group does not interfere, and mercuriation provides a convenient route to 5-bromo-4-nitroisothiazole (Scheme 30).106... 

Acetyl- and 5-formylisothiazoles are readily available from 5-lithioisothiazoles.71,102 However, 3-methyl-4-nitroisothiazole does not form a lithium derivative,72 and 4-formyl-3-methyl-4-nitro-isothiazole was prepared by reduction of the appropriate acid chloride with lithium tri-Lbutoxyaluminum hydride.140 A 5-formyl-4-hydroxy-isothiazole has been prepared by direct ring synthesis [Eq. (12)].29... 

The action of the sulfuric-nitric acid mixture on isothiazole gives a high yield of the corresponding 4-nitro derivative [190, 192, 193] (Scheme 18). 

Examples of the ipso-nitration of halogen-substituted isothiazoles [387] and thiazoles [388-390] are known. 2,4-Disubstituted 5-bromo- and 5-iodooxazoles react with nitrogen tetroxide to form the 5-nitro derivatives [391],... 

Recently, Schulze and coworkers synthesised a group of (2-aryl-4,5-diphenyl)isothiazol-3-ylidenes (see Figure 6.11) by deprotonation of the respective isothiazolium perchlorates with Bu OK as base [37], The compounds are yellow solids that dimerise readily and show typical carbene reactions like insertion into NH bonds. The tendency to dimerise follows the known electronic properties of substituents on the phenyl ring on nitrogen (< -methyl [Pg.317]

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