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ABSTRACT:
Benzothiazepines are fused heterocyclic compounds. They are claimed of various therapeutic activities and hence, they are utilized in drug research. Recently, attention is being directed to their synthetic methods, chemical and biological properties. Benzothiazepines posses wide variety of biological activities like anticonvulsant, CNS depressant, Ca++ channel blockers, calcium channel modulator, calcium channel antagonist, anticancer, anti fungal antimicrobial, anti-HIV and anti-anginal.
KEYWORDS: 1,5-benzothiazepine, CNS, Green synthesis, Microwave -assisted.
INTRODUCTION:
Benzothiazepine is a heterocyclic compound that contains a benzene ring fused with, a seven membered ring, having nitrogen and sulphur. Benzothiazepine derivatives are of two types; 1) 1,4-benzothiazepine and 2) 1,5- benzothiazepine, as shown in Fig. 1.
Benzothiazepines exists in two tautomeric forms i.e imino and enamino structure. as shown in Fig. 2.
In the imino structure of 2, 4-substituted-1,5- benzothiazepines, C2 is the chiral centre having methine proton and C3 is a prochiral centre bearing two methylene protons, where HA and HB are the two hydrogen, one of which is equatorial and the other is axial. The hydrogen gives peculiar pattern in PMR spectra and appear as double doublets .Substitutions on this hydrogens produces isomers. The enamino form has one methine proton at C2 chiral center, but has only one proton at C3 and be easily distinguished by appearance of only doublet for C2 and C3 proton.
Benzothiazepines have been claimed of various therapeutic activities, but the investigation of their chemistry commenced rather slowly. Benzothiazepines posses wide variety of activities like anticonvulsant, CNS depressant, Ca++ channel blockers, anticancer, anti fungal, antiviral, antitumor, anti-HIV, antimicrobial, etc. The molecule has structural resemblance to benzodiazepam, established CNS depressant and hence can be used as its bioisosteric replacement. However there are less reports on the CNS action specially anticonvulsant and CNS depressant activity. This review article aims to cover many previous as well as latest research explaining synthetic protocols and diverse biological activities. The comprehensive literature survey of 1,5-benzothiazepines will help the upcoming researchers to synthesize the novel derivatives possessing various therapeutic effects
Synthesis of 1, 5-Benzothiazepines:
Several methods for synthesis are available in literature which involves conventional, microwave as well as combinatorial synthetic methods. Benzothiazepine are prepared by condensation of 2-aminothiophenol with carbonyl compounds. Various research groups have reported methods of synthesis for 1, 5-benzothiazepines. Following...