Mailing Address : Department of Chemistry, Indian Institute of Technology, Powai, Bombay-400 076, INDIA.
E-mail: email@example.com , Ph. 91-22-5782545 Extn. 3176, Fax 91-22-578 3480 .
Date of Birth : 14 th April, 1967
Citizenship : Indian
Marital Status : Unmarried
Academic Record :
1991 to date: Ph.D.(Organic Chemistry). Thesis to be submitted shortly to Indian Institute of Technology, Bombay, INDIA.
1987-1989: M.Sc. in (Organic) Chemistry with First Class Mahatma Gandhi University, Kottayam, Kerala, INDIA.
1984-1987: B.Sc. (Chemistry Major along with Physics and Mathematics) with First Class University of Kerala, INDIA
Association with Industrial R & D :
Served as R & D Chemist from Feb. 1990 to Aug. 1990 in a project entitled "Development of Cardol and Cardanol Based Resins and their Applications"
Awards and Scholarships :
Proficiency / Skills:
Organic Synthesis : Total synthesis of natural products, Synthesis of novel biologically interesting molecules, Photochemical reactions in organic synthesis, Studies on pi-facial selectivity in the Diels-Alder reactions of facially differentiated cyclicdienes.
Chromatography : HPLC, GLC, Column Chromatography and preparative TLC.
Spectroscopy : High Field NMR, IR, UV, Mass spectroscopy.
Computational skills : Operating system DOS; Chemdraw, Chemwindows & MS Word on Windows.
Recent Research Interest:
List of Publications:
1. Photochemical Reactions of alpha-Methoxy-beeta,gamma-enones: Isolation of 1,2-Acyl Shift Intermediate and Synthesis of Versatile Precursors to Oxygenated Capnellanes. Vishwakarma Singh and Prathap S.,Synlett,542, 1994.
2. Photochemical Reactions in Organic Synthesis : A Novel and Efficient Route to Angular and Linear Tetraquinanes, Vishwakarma Singh and Prathap S.,Tetrahedron, 1996 (in Press).
3. Aromatics to sesquiterpene : a novel, stereospecific total synthesis of capnellene from p-cresol, J. Chem. Soc., Chem. Commun.,1996, (communicated).
4. Synthesis of Cyclicdienes Fused to Bicyclo[2.2.2]octene Framework and pi-Facial Selectivity in the Diels - Alder Cycloaddition: A Remarkable Electronic and Steric Effect, Tetrahedron Letters, (communicated).
5. An unusual Prins type reaction on isoeugenol in basic media: Structure of the adduct and its transformation to tricyclo- [126.96.36.199]undecane system (manuscript under preparation).
6. Photochemical 1,2-Acyl Shift in beeta,gamma - Enones : Synthesis of Versatile Precursors to Capnellene and Oxygenated Capnellenes, (manuscript under preparation)
Summary of Ph.D. Project :
In the first year of Ph.D. Program, suitable advanced courses viz. Organic Synthesis, Organic Reactive Intermediates, Topics in Chemistry, Spectra of Organic Compounds, Stereochemistry and Reactivity of compounds and Advanced Laboratory Techniques were credited which covered in-depth understanding of chemistry and research in the frontiers. These were qualifiers for registration for the degree and were successfully completed. For the degree of Ph.D., the research work was carried under the guidance of Prof. V.K Singh at Department of Chemistry, Indian Institute of Technology Bombay, India. The topic of research was "Photochemical 1,2-Acyl shift in beta, gamma-Enones: Synthesis of Tri and Tetraquinanes". Occurrence and isolation of a large number of polyquinane natural products have stimulated a world wide interest in the chemistry of polycyclopentanoids which is continuing. This is partly due to novel and intricate carbocyclic network of the natural triquinanes and also because of diverse biological properties exhibited by some members. For example, the capnellanes display biological activities similar to those of their terrestrial counter parts, the hirsutanes, which possess antibacterial and anti-tumor properties. These metabolites function as chemical defense agents within the coral reef, warding off algal and microbial growth in addition to preventing larval settlement.
Recently the synthetic potential of photochemical sigmatropic 1,2 and 1,3- acyl shifts have been demonstrated by our group. In continuation with our efforts in this area and to demonstrate the synthetic potential of the methodology developed in our group, we embarked upon a program to develop shot and efficient route to triquinane natural products like capnellene, oxygenated capnellenes and tetraquinanes employing photochemical 1,2-acyl shift as a key step.
A novel, efficient and stereospecific total synthesis of capnellene from p-cresol has been successfully carried out. The strategy involved inverse demand cycloaddition and photochemical 1,2-acyl shift which is particularly attractive with regards to its unusually wide versatility and to the extraordinary clean and selective reaction, as key features. Other reactions utilized for the total synthesis were reduction, oxidation, selective protection, reductive deoxygenation, Barton's reaction and Wittig reaction.
Only a few routes are known for the synthesis of more demanding Oxygenated Capnellenes. The work on highly functionlized triquinanes which are potential precursors to oxygenated capnellenes has been carried out successfully employing photoreaction of strategically designed tricycloundeccadienones having alpha-alkoxy - beeta, gamma unsaturated carbonyl chromophore. The intermediate formed during the photoreaction of alpha-alkoxy-beeta,gamma enones was isolated for the first time and its intermediacy in the photoreaction has been proved. All the precursors along the route have been fully characterized through detailed analysis of proton NMR,Carbon-13 NMR and COSY spectra.
The interest in tetraquinane has been due to their synthetic potential towards higher polyhedra of undamental significance such as dodecahedrane, hexaquinane and peristylene. Linearly fused tetraquinane have provided the carbocyclic network of some unusual natural products like fusicoccins and ophibilines, which possess a wide spectrum of biological activities. Novel and efficient routes to angularly and linearly fused tetraquinance have been developed.The synthesis involved triplet sensitized photoreaction of appropriately appended tricyclo[188.8.131.52]undecane systems followed by ring annulation via aldol condensation. In another exciting work various facially differentiated cyclicdienes fused to bicyclo[2.2.2]octene framework were synthesized and their cycloadditions toward various dienophiles such as benzoquinone and DMAD were carried out, wherein remarkable electronic and steric effects have been observed. Proton NMR, carbon-13 NMR and NOE were used to characterize the cycloadducts.
1. Prof. V.K.Singh*, Dept. of Chemistry, Bombay-400076, India.
2. Prof.K.D.Deodhar, Dept. of Chemistry, Bombay-400076, India.
3. Prof.S.R.Kotha, Dept. of Chemistry, Bombay-400076, India.
* Research supervisor