xxvii ABSTRACT OF THE THESIS

Transcription

1 xxvii ABSTRACT F TE TESIS Synthesis, Characterization and Biological Activities f ovel ybrid Molecules Related to Substituted ydrazones, Sulphonamides and Sulphonates of on- Steroidal Anti-Inflammatory Drugs CAPTER 1 A Brief verview of Synthesis and Pharmacological Activities of Substituted ydrazones, Sulphonates and Sulphonamides This chapter deals with general survey of the literature related to the present topic which describes pharmacological importance, synthesis and the synthetic utility of substituted hydrazones, sulphonates and sulphonamides. -acyl hydrazones which are pharmacologically important has been combined with on-steroidal anti-inflammatory drugs such as aproxen and Ibuprofen drugs used for the treatment of inflammation and also used as an antipyretic agents. There are conditions when an inflammation occurs in response to a microbial infection, and a combination of the anti-inflammatory drug with antimicrobial agent is prescribed in such conditions. These combinations often cause side effects because of high doses of drugs. Searching for new compounds, which would combine two activities seem to be promising way to overcome that problem. Sulfonates and sulfonamides as we know that these are the main drugs which are used as antibacterial agents. In light of these

2 xxviii observations, we became interested in the synthesis, characterization and biological evaluation of hybrid molecules related to -acyl hydrazones, sulfonates and sulfonamides. In order to assess more accurately and to provide a background frame work for the work described in this thesis, a survey was undertaken of the relevant literature. The details of synthesis and phamacological activity were presented in this chapter. CAPTER 2 Synthesis, characterization, cytotoxic and antibacterial study of aproxen derivatives This chapter deals with a detailed study of synthesis, characterization and cytotoxicity activity propionic acid based hybrid molecules related to aproxen (1) and -acylhydrazones (Scheme 1). Pharmacological importance of -acylhydrazones and the gastro intestinal side effects of aproxen prompted us to plan the synthesis of new derivatives containing both the skeletons. The condensation of the key intermediate, i.e aproxen based -acylhydrazine (2) with aldehydes and ketones produced -acylhydrazones or 1-aroyl-2-ylidene hydrazines 3a-j and 4a-j respectively under conventional way using PEG-400 as solvent at room temperature and under microwave irradiation. It was observed that the duration of the reaction time was 8-10 h under conventional way where as it was completed within 5 min under micro wave promoted reaction condition. All the compounds synthesized by following this methodology were fully characterized based on their IR,

3 xxix Mass and 1 MR spectral data. All the compounds synthesized were found to exist as a mixture of two rotameric forms in solution e.g. antiperiplanar (ap) and synperiplanar (sp) as indicated by their 1 MR spectra. Further it was supported by the analysis of 1D 1 MR and 1-1 2D M CSY spectra of a representative compound. The X-ray diffraction study of the single crystal (Figure 1) of another representative compound confirmed that the molecule exists as an -bonded symmetrical dimeric ap form in the solid state. The crystallographic data has been deposited with the Cambridge Crystallographic Data Centre (CCDC ). 3 C Me/ + 3 C 2 4 / Et 1 2 Scheme1 2 Figure1 ArC/ RC PEG 400, RT or MW ArCR PEG 400, RT or MW 3 C 3 C 3a-j Ar/R Ar/R Ar/R 4a-j 3 C Me

4 xxx The derivatives prepared from aldehydes were screened cytotoxicity (anti cancer) activity against human lung adenocarcinoma cell line (A549) and were observed that most of the compounds exhibited promising anti-cancer activity. As hydrazones also possess Antibacterial activity, the derivatives synthesized from ketones were screened for the activity against various Gram ve and Gram +ve bacteria, and most of the showed promising anti-bacterial activity. Thus the present study indicates that derivatives of aproxen could be a new and potential scaffold that needs further exploration for design and SAR studies for the development of novel anticancer agents. CAPTER 3 Synthesis, characterization, cytotoxic and antibacterial study of Ibuprofen derivatives In Chapter 2 we have described the synthesis, characterization and cytotoxic study of a series of Ibuprofen and -acylhydrazone (Scheme 2) based new hybrid molecules. ur sustained interest in the synthesis of covalent biotherapy based new hybrid molecules prompted us to explore the synthesis of pharmacologically interesting -acylhydrazone and one more propionic acid Ibuprofen. The condensation of the key intermediate, i.e ibuprofen based - acylhydrazine (6) with aldehydes and ketones produced - acylhydrazones or 1-aroyl-2-ylidene hydrazines 7a-j and 8a-j respectively under conventional way using PEG-400 as solvent at room temperature

5 xxxi and under microwave irradiation. It was observed that the duration of the reaction time was 8-10 h under conventional way where as it was completed within 3.5 min under micro wave promoted reaction condition. All the compounds synthesized by following this methodology were fully characterized based on their IR, Mass and 1 MR spectral data. Scheme 2 ArC/ RC PEG 400, RT or MW Ar/R 2 Me/ / Et 5 6 ArCR PEG 400, RT or MW 7a-j 8a-j Ar/R Ar/R The compounds synthesized were tested against human lung adenocarcinoma cell line (A549) in vitro to assess their cytotoxicity activity. As of our interest in producing more cytotoxic agents we were successful in synthesizing the Ibuprofen based hydrazones which has showed more cytotoxicity than aproxen based hydrazones. The compounds synthesized by ketones were also active against different Gram ve and Gram +ve bacterial to assess their antibacterial activity.

6 xxxii CAPTER 4 Synthesis of Piroxicam and Paracetamol Sulphonate molecules and Evaluation of their Biological Activity Piroxicam (9), a selective CX 2 inhibitor is a SAID to oxicam class of SAID, widely used for the treatment of inflammatory conditions in patients suffering from rheumatism. Piroxicam derivatives show remarkable antibacterial activity, anti viral property. n the other hand, sulfonates also illustrate extremely inspiring range of biological activities. Thus combining Piroxicam with sulfonyl chlorides to get new sulfonate (Scheme 3) hybrid molecules were synthesized and their Antibacterial activities were tested. These sulfonate esters 10 a-l were prepared by treating sulfonyl chloride with piroxicam in the presence of Et3 and Chloroform as a solvent in conventional method. The reaction time was very less when these very reacted in microwave irradiation and the yield was good when compared with that of the conventional method. Scheme 3 S C ArS 2 Cl Et 3, CCl 3 S S Ar C 9 10 a-l The compounds synthesized were screened for antibacterial activity. Most of the compounds showed moderate to good activity against various bacteria.

7 xxxiii Paracetamol (11) is widely used as analgesic and antipyretic drug. ere in we report the synthesis of new sulfonate molecules (Scheme 4) by combining sulfonyl chlorides with paracetamol in the presence of Et3 and chloroform as a solvent. The sulfonate esters 12a-g prepared were tested for antibacterial activity. Unfortunately sulfonates prepared from Paracetamol showed less antibacterial activity than the sulfonates prepared from piroxicam which showed promising activity against various bacteria. Scheme-4 CC 3 CC 3 ArS 2 Cl Et 3, CCl a-g s Ar CAPTER 5 Synthesis characterization and pharmacological activity of imesulide based sulphonamides Sulfonamides play a versatile role in many medicinal chemistry analogue programs, these are a very important class of compounds in the pharmaceutical industry, being widely used anticancer, anti inflammatory and antiviral agents. rganic sulfur compounds are widespread in numerous natural products and widely used as various artificial chemicals. In this chapter we synthesized some of the sulfonamides from imesulide (13) which is an anti inflammatory drug.

8 xxxiv The sulfonyl chlorides prepared by using chlorosulfonic acid were reacted with nimesulide which was reduced with Sn/Cl to produce sulfonamides. We were able to synthesize very few compounds 14a-d, because of various drawbacks such as long reaction time, tedious manipulations in the isolation of the pure products, and very less yield. Many trials were made by changing the solvent, reaction conditions, and the reagent, but we were not successful in preparing these sulfonamides in good yield. Scheme-5 S 2 C 3 ArS 2 Cl S 2 C 3 Et 3, CCl 3 2 S Ar 13 14a-d Figure 2 S 2 C 3 S CC 3