Crystal structure and conformational studies of some biologically important organic compounds

Abstract

The objective of the thesis is to determine the crystal structure of the biologically important organic compounds by X-ray diffraction methods and analyse the conformational features which have applications in medicinal, biological and pharmaceutical fields. Out of the sixteen compounds studied, five of them belong to chromenopyrroles, two indoles, three pyrrolidines, one pyrrolopyrrole, three pyrrolizines, one piperazine and a furan compound. The antibacterial activities of six compounds are studied and the screening results are presented. The docking studies of four compounds are carried out and the results are analysed. The work reported in this thesis is divided into seven chapters with the addition of two appendices. Chapter 1 presents a brief summary of the crystal structure determination methods and the importance of heterocyclic compounds. The five- and six-membered heterocyclic ring compounds occupy a prominent place among various classes of organic compounds for their diverse biological activities. The three-dimensional structure details of the compounds are given in Chapters 2 to 7. Chapter 2 describes the crystal structure analysis of five chromenopyrrole derivatives, namely (3aS,9bR)-Methyl 1-methyl-3-phenyl- 1,2,3,3a,4, 9b-hexahydrochromeno[4,3-b] pyrrole-3a-carboxylate [CP1], Methyl 3-(4-chlorophenyl)-1,2,3,3a,4,9b-hexahydro-1-chromeno[4,3-b]pyrrole- 3a-carboxylate [CP2], (3aRS,9bSR)-3-(4-Chlorophenyl)-1-methyl-1,2,3,3a, 4, 9b- hexahydrochromeno[4,3-b]pyrrole-3a-carbonitrile [CP3], Methyl 1-methyl-3-p-tolyl-1, 2, 3, 3a, 4,11c-hexahydrobenzo[f]chromeno[4,3-b]- pyrrole 3acarboxylate CP4] and Methyl 3-(4-bromophenyl)-1-methyl-1, 2, 3, 3a, 4, 9bvii newlinehexahydrobenzo[f]-chromeno [4,3-b] pyrrole-3a-carboxylate [CP5]. The compounds CP1 and CP2 crystallize in triclinic system with space group P1, whereas CP3 and CP5 in monoclinic space group P21/c and CP4 in space group P21/n. All the structures are solved by direct methods and refined by full-matrix least-squares procedures.