Karim's Research
Research Areas
Dr. Mohammad R. Karim
Synthesis and Characterization of New Schiff bases: There is a continuing interest in the design and synthesis of molecules that efficiently bind to DNA and cleave it. In particular, the study of organic chelating agents containing nitrogen and sulfur as the donor atoms and their metal complexes has become a subject of intensive investigation. In this regard, the use of bidentate NN chelating agents such as 1, 10-phenanthroline (phen) has played an important role in synthetic and medicinal chemistry. 1,10-Phenanthroline has also been used extensively as a ligand in both analytical and preparative coordination chemistry as well as in the preparation of many mixed-ligand complexes. 1,10- Phenanthroline and ligands derived from it as well as some of their metal complexes have also been found to be widely used in areas such as molecular catalysis, solar energy conversion, calorimetric analysis, herbicides, molecular recognition, self-assembly, antineoplastic agents, and nucleic acid probes. It has been found that Schiff bases formed by condensation of S-alkyl/aryl esters of dithiocarbazaic acid with heterocyclic aldehydes and ketones contain both ‘hard’ nitrogen and ‘soft’ sulfur donor atoms. Consequently, they are capable of forming stable complexes with a wide variety of metal ions, some of which have also been found to exhibit interesting physico-chemical properties and potentially useful chemotherapeutic properties.
Since organic and polymeric magnets offer advantages over traditional magnets because of the diversity of their structures, low density, low magnetic loss and process of preparation without metallurgy at high temperature, studies involving the synthesis of Schiff bases using 1,10-phenanthroline-2,9-dicarboxaldehyde and sulfur-containing primary amines deserve more attention. We, therefore, have undertaken the synthesis and characterization of new Schiff bases formed from 1,10-phenanthroline-2,9-dialdehyde and some sulfur-containing amines.
Synthesis of Curcumol: Curcuma wenyujin was used in traditional Chinese medicine for the treatment of various cancers including cervical carcinoma, vulva cancer, skin neoplasm, thyroid tumor, esophageal neoplasm, gastric, and intestinal cancer. Curcumol, one of the major components of the essential oil with the structure of sesquiterpene hemiacetal was found to have obvious anti-tumor activity. The structure of Curcumol has been established in 1965, and later it’s stereostructure was confirmed by X-ray analysis in 1984. This compound showed a very strong toxicity (ID50 of rats is 250mg/kg). Thus further structural modifications of curcumol to generate new analogs with increased water solubility, improved bioactivity and less toxic may provide high utility in cancer and other diseases treatment. Several metabolites from microbial transformation of curcumol has been isolated and structures were determined. [Chem Pharm Bull., 55(3) 451-454 (2007)]. Bioactivity of these metabolites has not yet been studied. We propose here a flexible synthetic route to these compounds which would allow us to synthesize a variety of these groups of compounds by slight modification of the starting materials.
Cembranoid Natural Products: Cembranoids are 14-membered ring containing diterpenes, found in marine invertebrates as well as in some plants and insects. Cembranoid diterpenes have been found to have a variety of biomedical applications, and hence synthetic investigations of these compounds have been carried out by many groups. A convergent retrosynthetic strategy has played a key role in designing the synthetic strategy of the Cembranoid key structure in our study. Few interesting reactions are planned to construct the key structure of Cembranoid. The detailed forward synthesis of these substructures and finally to target compound are planned.