synthesis of schiff and mannich bases of isatin derivatives with 4-amino-4,5-dihydro-1h-1,2,4-triazole-5-ones合成的希夫曼尼希碱与4-amino-4靛红衍生物,5-dihydro-1h-1,2,4-triazole-5-ones.pdf

Molecules 2008, 13, 2126-2135; DOI: 10.3390/molecule OPEN ACCESS molecules ISSN 1420-3049 /molecules Article Synthesis of Schiff and Mannich Bases of Isatin Derivatives with 4-Amino-4,5-Dihydro-1H-1,2,4-Triazole-5-Ones Olcay Bekircan 1, * and Hakan Bektas 2 1 Department of Chemistry, Karadeniz Technical University, 61080 Trabzon, Turkey 2 Department of Chemistry, Giresun University, 28049 Giresun, Turkey; E-mail: hakanbektas@.tr * Author to whom correspondence should be addressed; E-mail: obekircan@. Received: 15 August 2008; in revised form: 28 August 2008 / Accepted: 1 September 2008 / Published: 10 September 2008 Abstract: Ethyl imidate hydrochlorides 1 were prepared by passing HCl gas through solutions of substituted benzyl cyanides and absolute ethanol. Ethoxycarbonylhydrazones 2 were synthesized from the reaction of compounds 1 with ethyl carbazate. Treatment of 2 with hydrazine hydrate leads to the formation of substituted 4-amino-4,5-dihydro-1H- 1,2,4-triazole-5-ones 3. Isatin and 5-chloroisatin were added to 3 to form Schiff bases 4 and N-Mannich bases 5 of these compounds were synthesized by reacting with formaldehyde and piperidine. Their chemical structures were confirmed by means of IR, 1H- and 13C-NMR data and by elemental analysis. Keywords: Ethyl imidate hydrochloride; ethoxycarbonyl hydrazones; 4-amino-1,2,4- triazole-5-one; isatin; Schiff bases; Mannich bases. Introduction Schiff bases are