Protonation and alkylation of cross-conjugated ω,ω’-bis(dimethylamino) ketones (ketocyanines) containing the piperidine ring and the synthesis of the corresponding thiapentacarbocyanine dyes

Autor: Vadim V. Kachala, Zh. A. Krasnaya, Evgeniya O. Tret’yakova, S. G. Zlotin
Rok vydání: 2010
Předmět:
Zdroj: Russian Chemical Bulletin. 59:812-819
ISSN: 1573-9171
1066-5285
Popis: Protonation or alkylation of 3,5-bis(3-dimethylaminoprop-2-enylidene)-1-methylpiperi-din-4-one with Et2O∙HBF4, Et3O+BF4-, Me2SO4, or Et2SO4 (1 equiv.) involves the endocy-clic N atom, yielding the corresponding piperidinium salts. With 2 equivalents of the above reagents, the reactions occur at two reactive sites (the N and O atoms) to give doubly charged 4-hydroxy or 4-alkoxy polymethine salts. Protonation and alkylation of ethyl 3,5-bis(3-dimethyl-aminoprop-2-enylidene)-4-oxopiperidine-1-carboxylate involve only the O atom, affording the corresponding singly charged 4-hydroxy and 4-alkoxy polymethine salts. The latter were used to obtain previously unknown meso-alkoxythiapentacarbocyanine dyes containing the 1-ethoxycarbonyl-1,2,3,6-tetrahydropyridine fragment in the polymethine chain.
Databáze: OpenAIRE
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