Iron chloride, clay-supported

Reaction of 6-formyl-5,7,8,9-tetrahydro-ll//-pyrido[2,l-b]quinazolin-ll-one (135) with Clayfen [K-10 montmorillonite clay supported iron(III) nitrate] in boiling methylene chloride for 2.5 h gave a mixture of 6,6-dinitro-6,7,8,9-tetrahydro (136) and 6-formyl-8,9-dihydro-ll//-pyrido[2,l-6]-quinazolin-ll-ones (137) (90JOC6198). 

Bhattacharjee369, who has brominated acetanilide suspended in aqueous solution of potassium bromide and hydrogen peroxide in presence of vanadium pent oxide catalyst. Chloroperoxidase has been mimicked using supported manganese phorphyrin catalyst in the oxychlorination of dimedone370 and by clay-supported iron(III) chloride in the oxy-chlorination of toluene and anisole371. The kinetics and mechanism of the haloper-oxidases have been studied extensively372,373. 

Resorcinol Derivatives. Aminophenols (qv) are important intermediates for the syntheses of dyes or active molecules for agrochemistry and pharmacy. Syntheses have been described involving resorcinol reacting with amines (91). For these reactions, a number of catalysts have been used / -toluene sulfonic acid (92), zinc chloride (93), zeoHtes and clays (94), and oxides supported on siUca (95). In particular, catalysts performing the condensation of ammonia with resorcinol have been described gadolinium oxide on siUca (96), nickel, or zinc phosphates (97), and iron phosphate (98). 

Activation. KIO clay may be used crude, or after simple thermal activation. Its acidic properties are boosted by cation exchange (i.e. by iron(III) or zinc(II) ) or by deposition of Lewis acids, such as zinc(II) or iron(III) chloride (i.e. clayzic and clayfec ). In addition, KIO is a support of choice for reacting salts, for example nitrates of thallium(III), iron(III) ( clayfen ), or copper(II) ( claycop ). Multifarious modifications (with a commensurate number of brand names) result in a surprisingly wide range of applications coupled with the frequent imprecise identification of the clay (KIO or one of its possible substitutes mentioned above), they turn KIO into a Proteus impossible to grab and to trace exhaustively in the literature. 

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