Aluminum anilide

Ring All lation. Ortho alkylation of IDA has taken on increasing commercial importance. Ortho ethylation, the first commercial process, is carried out (5—8) using an alkyl aluminum haUde or an aluminum anilide. The alkylation rate decreases for higher alkenes (1). 

The preparation of 1-ethylphenothiazine by reacting phenothiazine with ethylene in the presence of aluminum anilide is of special interest. The orientation was proved by thionation of 2-ethyl-diphenylamine. A mechanism involving an A-aluminum derivative which sterically favors the substitution in position 1 by the intermediate formation of a cyclic complex would account for this course of the reaction. 

An alternative but equally cumbersome synthesis utilizes the more accessible bis(2-carboxyphenyl)disulfide, easily prepared from anthranilic acid. Byconversion to the corresponding anilide, then by successive reduction with zinc dust and acetic acid (yielding 2-mercaptobenzoyl anilide) and lithium aluminum hydride, the aldehyde (6) is obtained in fair overall yield.Although... 

The structure XXII for rhynehophylline has been confirmed, and the relative stereochemistry at C-15 and C-20 has been elucidated, by a total synthesis (80) of (+) JV-methylrhynchophyllane (XXVI) (Marion s N-methylisorhynchophyllane), which had been prepared earlier by methyl-ation of (iso)rhynchophyllane with sodium methoxide and methyl iodide (28). The lactone (XXVII) of threo-3,4-diethyl-5-hydroxyvaleric acid was converted by reaction with phosphorus pentachloride into the corresponding S-chloroacid chloride (XXVIII), which on treatment with methylaniline gave the anilide XXIX. Reduction of XXIX with lithium aluminum hydride gave the aldehyde XXX, which slowly reacted with... 

The practical procedure is as follows The methylanilide is dissolved in dry tetrahydrofuran and treated at 0°, portionswise, with powdered lithium aluminum hydride (1/3 to 1/2 mole per anilide group) or with a solution of the hydride in ether. Much heat is evolved, this being countered by cooling in ice-salt mixture. At the end of the optimal time for reduction, the mixture is hydrolysed by dilute acid, with ice-cooling. According to its properties, the aldehyde is isolated by extraction or by distillation in steam. 

Several examples of organoaluminum-catalyzed hydroamination of amino-alkenes have been reported recently. The neutral amido bis(anilide) 27 [37] and the aluminum pincer diolate complex 28 [114] displayed low catalytic activity and were only applicable to gem-disubstituted aminopentenes (Fig. 7). 

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