One pot Synthesis and Antibacterial activity of 3-substituted derivatives of14,15-diimino-10-nitro-benzothiazolo[2,3-b]pyrimido[5,6-e]pyrimido[2,1-b][1,3]benzothiazole
Anil B. Chidrawar
P.G. Department of Chemistry, Degloor College, Degloor - 431717, Dist: Nanded.
Swami RamanandTeerth Marathwada University, Nanded, Maharashtra, India.
Abstract : 3-cyano-4-imino-2-methylthio-8-nitro-4H-pyrimido[2,1-b][1,3]benzothiazole(I) independently on condensation with 2-amino-6-substituted benzothiazole in the presence of DMF and catalytic amount of K2CO3 reflux for 5-6 hours to yield 3-substituted derivatives of 14,15-diimino-10-nitro-benzothiazolo[2,3-b] pyrimido[5,6-e] pyrimido[2,1-b][1,3] benzothiazole (III-a-e).The synthesized compounds were characterized by elemental analysis and spectral data.
Key Words : 3-cyano-4-imino-2-methylthio-8-nitro-4H-pyrimido[2,1-b][1,3]benzothiazole, DMF, Potassium carbonate.
Introduction :
A one pot synthesis is a green approach towards the synthesis of various heterocyclic compounds and for a researcher there is lot of scope to change the reaction condition, to change the solvent, to change the catalyst or to modify the catalyst or even to develop various novel one pot chemical reactions. Pyrimidine, iminopyrimidine, pyrazole and fused benzothiazole heterocycles are reported to be effective pharmacophores [1-10]. A survey of literature made it evident that very little work has been carried out on the synthesis of fused pyrimidobenzothiazole possessing three to four rings which exhibit a wide spectrum of biological and pharmacological activities.
Pyrimido [2,1-b] benzothiazole and its 8-substitued derivatives were synthesized by Nair Mohan D. et.al.[11]by refluxing diethyl ethoxymethylenemalonate with respective 2-amino benzothiazoles. These derivatives were found to have antiviral activity.
A comprehensive review on the methods of preparation and reactions of iminopyrimidines has been published in the form of book, “The Pyrimidines” by Brown D.J.et al.[12-13]Imino compounds are known to possess some sedative and hypnotic actions. Denny W.A. et al.[14]reported fused pyrido, -imidazo, -pyrazolo, -pyrazino and -pyrolloheterocycles as topoisomerase-targeted anticancer agents. Jimonet Patrick and his research group [15] reported synthesis and pharmacological activity of 6-(trifluoromethoxy)-3-substituted-2-imino benzothiazolines. These compounds were found to be three times more potent than 6-(trifluoromethoxy) - 2-benzothiazolamine (Riluzole), a blocker of excitatory amino acid mediated neurotransmission. Erlenmeyer and Von Meyenburg [16] reported the preparation and moderate sedative activity of 5,5-dialkyl-2-imino-4-thiazolidones which is in marked contrast to the lack of activity of the iminobarbituric acids [17-20].