- Orthoamides. LII. Contributions to the synthesis of carboxylic ortho acid amides
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The formamidinium salts 11a, c as well as the nitrile 12 react with sodiumhydride/dimethylamine in the presence of trimethylborate to give the ortho formic acid amide 3a. The orthoamides 6a and 16 can be prepared from the iminium salts 15 and 14, resp. by the same procedure. Treatment of the azavinylogous formamidinium salt 15 with sodiumhydride and piperidine or morpholine in the presence of trime-thylborate affords the orthoamides 6c and 6d, resp. By transamination of the azavinylogous aminalester 5a are accessible the orthoamides 6b-d. The vinylogous orthocarbonic acid derivative 17 can be obtained from the salt 14 and sodium alcoholates. The action of sodiumhydride, dimethylamine and trimethylborate on the iminium salt 18 produces a mixture of the orthocarbonic acid derivatives 7a, 8a, 9a. When the guanidinium salt 20 is treated with the same reagents the ortho-amides 3a and 10a are obtained. The reduction of the salt 20 with sodiumhydride in the presence of several activating reagents (e.g. tetrabutyl orthotitanate, aluminiumisopropylate, trimethylborate) affords the orthoamide 3a. The reduction of the iminium salts 18 and 24 does not proceed clean, giving mixtures of various orthoformic acid derivatives. The form-amidine 25 can be prepared by reduction of the salt 15 with sodiumhydride/trimethylborate with good yields. By the action of the corresponding carbanions on the guanidinium salt 20 can be obtained the carboxylic acid orthoamides 26-33. By the same procedure the orthoamides of alkyne carboxylic acids 36a-h, j-n are accessible. Wiley-VCH Verlag GmbH, 2000.
- Kantlehner, Willi,Stieglitz, Ruediger,Hauber, Michael,Haug, Erwin,Regele, Claudia
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p. 256 - 268
(2007/10/03)
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- Process for preparing diphenylamines
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A process is described for preparing diphenylamines of the formula STR1 by oxybromination of a phenol ether compound using elemental bromine in the presence of hydrogen peroxide and of a catalyst to give a brominated phenol ether compound which is subsequently reacted with a formanilide compound to give the compound of the formula (1). The oxybromination reaction is a regioselective, environmentally friendly and cost-efffective method of preparing brominated aromatic compounds. The diphenylamines of the formula (1) are industrially useful intermediates for the production, for example of dyes, and in particular of color formers of the fluoran type for pressure- or heat-sensitive recording systems.
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