New Synthetic Routes towards Natural and

Proposal
Title of the project: New Synthetic Routes towards Natural and Unnatural Biologically
Active Nostodione A and Azacarbolines
Preamble
Heterocycles form the largest class of organic molecules which are of immense importance biologically
and industrially. Apart from that many heterocyclic compounds are used as cosmetics, in reprography, for
information storage, and plastics. Heterocyclic compounds like carbazoles, tryptamines, carbolines,
meriadinim G, variolin B, porphobilinogen etc show medicinal properties. The isolation and evaluation of
biological and chemical properties of natural products have attracted attention of organic chemists,
medicinal chemists, biologists and pharmacists. Chemical and biological research has also presented a
great challenge to synthesize and optimize highly efficient and economical synthetic routes to novel
biologically active substances.
Issues of Focus
Heterocycles dominated medicinal chemistry from the beginning. In practice, most commonly found
hetero atoms are nitrogen, oxygen and sulphur. Indole derivatives have been a topic of substantial
research interest and continues to be one of the most active areas of heterocyclic chemistry, particularly
due to the natural occurrence and pharmacological activities. A large number of indole derivatives are
biologically active, lead compounds for drug development. Indole derivatives occur widely in many
natural products obtained from plants, fungi and marine organisms. Indole alkaloids include simple as
well as more complexly functionalized indole derivatives. The simple derivatives are comprised of
carbazoles, carbolines etc. More complex indole derivatives usually contain additional fused rings of
various sizes and some examples are isocryptolepine, calothrixin B, canthines and isocanthines etc. These
exhibit bioactivities like-antitumor and cytotoxicity. Several synthetic methods are reported for simple
and complex indole derivatives. However there is a need of efficient synthetic routes for new systems
having indole skeleton and also to evaluate their biological activities.
Objectives/ Research Focus
Considering the importance of indole alkaloids in terms of various biological activities and
pharmacological activities, the objective planned is to develop new synthetic methods for indole
containing scaffolds. Using the literature survey, systems like aza carbolines are selected as target
molecules. Particularly, 1-substituted-3-aza-β-carbolines and 4, 5-disubstituted 6-aza γ-carbolines were
chosen as targets of interest. Various well known reactions like Pd catalyzed Heck type coupling,
cyclization, Pictet Splengler type condensation and aza-electrocyclization would be used for the synthesis.
After establishing efficient routes for these molecules, synthesis
of analogues having appropriate substituents and evaluation of biological activity would be also
undertaken.
Reasons & Justification
Literature survey revealed that these systems are less explored than β-carbolines and γ-carbolines
with respect to biological activities as well as synthetic studies. Thus, there is a need to develop new and
efficient routes for these types of compounds and also to synthesize analogues and evaluate their
bioactivity.
Deliverables
Most of the selected target molecules and intermediates in this proposal are new organic molecules. The
intermediates may have importance in the synthesis of some other targets as would be demonstrated in the
planned synthesis of nostodione A in Section 3. In addition to this, the proposed targets as well as
intermediates might be useful as bioactive compounds.
Work Plan
Section 1
In our group, synthetic methods are developed earlier for indole derivatives like carbazoles,1 βcarbolines,2 γ-carboline,3 α-carbolines,4 azaindoles5 etc. Most of these systems are having indole skeleton
with fused benzene ring with or without one heteroatom. Having expertise in handling these types of
molecules, in the present proposal, indole system with fused benzene ring having two hetero atoms
(nitrogens) such as aza carbolines would be envisioned. Thus, 1-substituted-3-aza-β-carbolines and 4, 5disubstituted 6-aza γ-carbolines were selected as target systems. It is reported6-12 that the parent as well as
diaza systems possess different types of biological activities like antitumor activity,6 cytotoxicity to tumor
cell lines,7 anthelmintic and antiprotozoal activity,8 antihypertensive,9 antitumor agents,10 antimicrobial11
serotonine antagonistic, antihistaminic, anxiolytic, and HIV-1 reverse transcriptase inhibitory activities.12
Harman is 1-methyl-β-carboline which exhibits13 mutagenic and co-mutagenic properties and inhibits
topoisomerase I. It is reported14 in literature that addition of alkyl chain at indole nitrogen N-9 enhances
the activity remarkably.
Considering the analogy with this, 3-azaharman was selected as the first target molecule. Synthetic
method would be developed for this target and subsequently 3-aza-β-carbolines with different substituents
at C-1 and N-9 would be synthesized using similar strategy. Evaluation of biological activity would reveal
the structure activity relationship in this system.
Synthetic plan for 1-substituted -3-aza-β-carbolines
In literature,12 there are very few reports available for 1-substituted-3-aza-β-carbolines and also for their
synthesis. In present proposal three new routes were envisioned for these 3-aza-β-carbolines as shown in
the retrosynthetic analysis in Scheme 1.
Thus, in Route 1, 2-acyl indole would be prepared using Fischer indole synthesis starting with
phenylhydrazine hydrochloride. Further, Vilsmeier-Haack reaction will give 3-formyl indole derivative.
The key step of this route would be formation of hydrazone followed by cyclization along with
dehydration to get the first target molecule 1-methyl-3-aza-β-carboline. For other analogues, substituents
selected at C-1 are 4-(2-aminopyrimidine), 3-indole and 2-pyridine since the corresponding β-carboline
derivatives like harman, annomontine, eudistomin U are well known naturally occurring alkaloids
showing various biological activities.
In Route 2, treatment of indole-3-hydrazone with appropriate aldehyde would give a substituted azine.
Further thermal aza-electrocyclization and aromatization would furnish 1-substituted -3-aza-β- carbolines.
In Route 3, starting from isatin, 2-chloro-3-formyl indole would be prepared using literature procedure. It
would be converted to hydrazone and then was reduced to substituted hydrazine. Further treatment with
appropriate aldehyde would result in the corresponding hydrazone. Subsequent acid catalysed Pictet
Spengler type condensation and dehydrogenation should give 1-substituted -3-aza-β-carboline.
Alternatively, Heck type of coupling reaction can also be used to give the target molecules.
In the last part, N-alkylation of the 1-substituted-3-aza-β-carbolines would be attempted. Biological
activity (cytotoxicity) would be tested for all synthesized compounds. By comparing the activities, effect
of substituents at N-9 and also at C-1 would be studied.
Scheme 1
Section 2
As mentioned earlier, in the next part, synthesis of 4, 5-disubstituted-6-aza-γ-carbolines would be
undertaken. γ-Carboline derivatives are reported15 to show various biological activities like anticancer
properties. However, in literature16 very few reports are available for aza-γ-carbolines. In the present
proposal a new synthetic route would be developed for 4,5-disubstituted-6-aza-γ-carbolines. The beauty
of the reaction would be the formation of both pyridine rings simultaneously on both the sides of pyrrole.
Synthetic plan for 4, 5-disubstituted 6- aza-γ-carbolines
The retrosynthetic plan for these target molecules is given in Scheme 2
Scheme 2
Starting with protected pyrrole, 2,5-dialdehyde would be prepared initially. Further, bi-functionalized
nitro-olefin would be formed which will be reduced to diamine. Subsequent Pictet Spengler condensation
and dehydrogenation would result in the target molecules, 4, 5-disubstituted 6-aza γ-carbolines. In the last
step N-alkylated derivatives would be synthesized. Testing of cytotoxicity of all synthesized analogues
would reveal the effect of placement of different groups at C-4, C-5 and N-9.
Section 3
Nostodione A was first reported in 1993. This structure was assigned to a fragment obtained upon
ozonolysis of the reduced form of scytonemin.17 Nostodione A was first isolated from biological source
cyanobacterium Nostoc commune18 by Kobayashi et al. Jerker Martensson et al. first time reported the
total synthesis of nostodione A.19
Nostodione A has been shown to suppress mitoticspindle formation in sea-urchin eggs and to inhibit
chymotrypsin-like proteasome activity in vitro.20 Nostodione A showed a moderate activity in the
proteasome inhibitory assay with an IC50 value of 50 µM.
Since an intermediate 2-acyl-3-formyl indole would be prepared in the synthetic sequence mentioned in
Section 1, it is envisaged to use this molecule for the synthesis of indole alkaloid nostodione A. In this
section it is planned to develop a new efficient method for nostodione A starting with 2-acyl-3-formyl
indole as shown in Scheme 3.
2-Acyl-3-formyl indole on aldol condensation will give aldol product which would be dihydroxylated to
diol. Further acetonide protection and Wittig reaction would result in the skeletal system of the target
compound. Deprotection followed by oxidation would lead to the target molecule nostodione A.
Scheme 3
Reference
1. Shrikar M. Bhosale, Aadil A. Momin, Radhika S. Kusurkar, Tetrahedron 2012, 68, 6420.
2. Radhika S. Kusurkar, Nabil A.H. Alkobati, Anita S. Gokule, Vedavati G. Puranik, Tetrahedron 2008 ,
64, 1654.
3. Dattatray G. Hingane, Radhika S. Kusurkar, Tetrahedron Letter 2011, 52, 3686–3688.
4. Neelam L. Chavan, Sandip K. Nayak, Radhika S. Kusurkar, Tetrahedron 2010, 66, 1827.
5. Abdullah M.A. Shumaila, Vedavati G. Puranik, Radhika S. Kusurkar, Tetrahedron 2011, 67, 936.
6. Guan, H.; Chen, H.; Peng, W.; Ma, Y.; Cao, R.; Liu, X.; Xu, A. Eur. J. Med. Chem. 2006, 41, 1167.
7. Ishida, J.; Wang, H. K.; Bastow, K. F.; Hu, C. Q.; Lee, K. H. Bioorg. Med. Chem. Lett. 1999, 9, 3319.
8. Ancolio, C.; Azas, N.; Mahiou, V.; Ollivier, E.; Di Giorgio, C.; Keita, A.; Timon-David, P.; Balansard,
G. Phytother. Res. 2002, 16, 646.
9. Monge, A.; Aldana, I.; Alvarez, T.; Losa, M. J.; Font, M.; Cenarruzabeitia, E.; Lasheras, B.; Frechilla,
D.; Castiella, E.; Fernandez-Alvarez, E. Eur. J. Med. Chem. 1991, 26, 655.
10. a) Menta, E.; Pescalli, N.; Spinelli, S. (Novuspharma S.P.A., Italy). Patent No. WO 2001009129,
2001; C. A. 134, 162922.
b) Ritzeler, O.; Castro, A.; Grenier, L.; Soucy, F. (Aventis Pharma Deutschland G. m. b. H., Germany).
Patent No. 1134221, 2001; C. A. 135, 242149.
c) Evanno, Y.; Sevrin, M.; Maloizel, C.; Legalloudec, O.; George, P.; Synthelabo, S. A. Patent No. WO
9815552, 1998; C. A.128, 282832.
11. Snyder, S. A.; Vosburg, D. A.; Jarvis, M. G.; Markgraf, J. H. Tetrahedron 2000, 56, 5329.
12.a)El-Kashef Hussein, Farghaly A. A. H., Floriani, S., and Haider, N.,
Arkivoc 2003, (xiv), 198-209.
b) Monge v, Antonio et al. Eur. J. Med. Chem. 1978, 13 (6), 573-5.
13. Ishida. J; Wang, H.K.; Bastow, K/F.; Chang, Q.H.; Lee, K. H. Bioorg. Med. Chem. Lett. 1999, 9, 3319
14. Haider, N. and Wobus, A., Arkivoc 2008 (vii) 16-25.
15. Bisagni, E.; Nguyen, C. H.; Pépin, O. US Pat. 4835160.
16. (a) Kaczmarek, L.; Becalski, A.; Nantka-Namirski, P. Pol. J. Chem. 1980, 54, 1585. (b). Wieczorek,
J.; Peczyńska-Czoch, W.; Mordarski, M.; Kaczmarek, L.; Becalski, A.; Nantka-Namirski, P. Arch
Immunol Ther Exp (Warsz) 1986, 34, 323.
17. Proteau, P. J.; Gerwick, W. H.; Garciapichel, F.; Castenholz, R. Experientia, 1993, 49, 825.
18. Kobayashi, A.; Kajiyama, S. I.; Inawaka, K.; Kanzaki, H.; Kawazu, K. Z. Naturforsch., C: J. Biosci.
1994, 49, 464.
19. Andreas Ekebergh, Anna Borje, and Jerker Martensson, Org. Lett. 2012, 14, 24.
20. Shim, S. H.; Chlipala, G.; Orjala, J. J. Microbiol. Biotechnol 2008, 18, 1655.
Program Schedule, including Activity Diagram/ Bar Chart:
The whole proposal would be divided into three parts. In the first year, synthesis and evaluation of
biological activity of 1-substituted-3-aza β-carbolines would be completed. In the second year, synthesis
of 4, 5-disubstituted-6-aza γ-carbolines would be completed and bioactivity evaluation would be carried
out. In the third year, new synthesis of nostodione A would be developed.
Y
e
a
r
s
4
3
2
1
0
A
B
Milestone
C
Milestone
A
B
C
Description
Synthesis and evaluation of biological activities of 1-substituted-3-aza βcarbolines
Synthesis and evaluation of biological activities of 4, 5-disubstituted 6-aza γcarbolines
Synthesis of nostodione A
6. Proposed budget:
a) Staff SRF
b) Emeritus Scientist Allowance
b) Contingency
Chemical, sample, glassware etc.
Maintenance
Information search (from data
bases)
Travel
Any other
c) Equipment (item wise)
1. Rota evaporator
2. Weighing Balance
3. Magnetic Stirrers
4. Hot Plates
5. computer accessories
d) Total
Total
1st year (Rs. in
Lakhs)
2.16 (+ HRA)
2.40
2nd year (Rs.in
Lakhs)
2.16 (+ HRA)
2.40
3rd year (Rs. in
Lakhs)
2.16 (+ HRA)
2.40
1.00
1.00
1.00
0.20
0.20
0.30
nil
0.20
0.20
0.30
nil
0.20
0.20
0.30
nil
2.5
0.50
0.50
0.50
0.50
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
10.76
23.28
6.26
6.26
Outcomes & Outputs: New routes would be developed for 1-substituted-3-aza β-carbolines, 4, 5disubstituted 6-aza γ-carbolines and nostodione A. Evaluation of bioactivity would be carried out. The
results would be published in international journals with good impact factor.
List of publications:
1. Diels–Alder Reactions of 2-(2-methoxy and 2-nitro)-vinylindole with acrylonitrile, ethyl
acrylate and acrolein acetal.
N. S. Narasimhan and R. S. Kusurkar
Indian Journal of Chemistry 1983, 22B (9), 846.
2. Diels –Alder Reactions of 2- vinylindoles with maleic anhydride.
N. S. Narasimhan, R. S. Kusurkar and (in part) D. D. Dhavale, Indian Journal of
Chemistry 1983, 22B (10), 1004.
3. An efficient synthesis of Phthalideisoquinoline Alkaloids
N. S. Narasimhan, R. R. Joshi, R. S. Kusurkar
J.Chem.Soc. Chem. Commun, 1985, 177.
4. A carbazole synthesis involving Diels –Alder Reactions of 3- vinylindoles
R. S. Kusurkar and U. G. Patil
Indian Journal of Chemistry 1986, 25B, 1038.
5. Synthesis of 3-(1’-propenyl) and 3-(1’-styryl) phthalides using lithiation reaction.
R. S. Kusurkar and R. N. Patil
Indian Journal of Chemistry 1990, 29B, 64.
6. Novel synthesis of benzosubstituted benzofurans via Diels –Alder Reaction
R. S. Kusurkar and D. K. Bhosale
Synthetic communications 1990, 20, 101.
7. α, β- Unsaturated oxime as a new heterodiene for the Diels-Alder reaction-Synthesis
of Furo[2,3-c] Pyridine N-oxides.
R. S. Kusurkar and D. K. Bhosale
Tetrahedron..Lett. 1991, 32 (27), 3199.
8. Cycloaddition Reactions of Conjugated aldoximes and ketoximes using
conventional dienophiles
Kusurkar, R.S; Gadre, Leena.; Kulkarni, M. M
Synthetic communications 1994, 24(5), 635.
9. Study of cycloaddition reactions of conjugated oximes with and without lewisacids.
Dehydrogenation of the Cycloadduct to isoxazoles.
R. S. Kusurkar, M.S. Wadia, D. K. Bhosale, S.S.Tawale, V.G.Puranik
J.Chem. Res. (S), 478, (1996), (M), 2701, (1996)
10. 1,3-Dipolar reactions for the synthesis of new substituted isoxazolidines and isoxazoles
Kusurkar, R.S; Bhosale, D. K.; Gadre, L.A.; Jain, J. J.; and Wadde, H.M.
Indian Journal of Chemistry 1998, 37B, 1239.
11. 1,3-dipolar Cycloaddition reaction assisted by microwave radiation and γ-radiation
Kusurkar, R.S.; Kannadkar, U.D.
Synthetic Communications, 2001, 31, 2235.
12. Reactions of Vilsmeier Haack reagent with aromatic and heterocyclic aldoximes
R. S. Kusurkar, S. K. Goswami and S.M. Vyas
Indian journal of Chemistry 2003, 42B, 3148-3151.
13. Efficient one-pot synthesis of anti HIV and antitumor compounds: Harman and
substituted Harmans
R. S. Kusurkar, S.K. Goswami and S.M. Vyas
Tetrahedron Letters 2003, 4761-4763.
14. Efficient one-pot synthesis of anti HIV and antitumor -carbolines
R. S. Kusurkar and S. K. Goswami
Tetrahedron 2004, 60, 5315- 5318.
15. Synthesis, Characterization and Performance evaluation of Triaryl Cyanurates.
Sandhya Vyas, V. N. Krishnamurthy, R. S. Kusurkar.
Theory and Practice of energetic materials Vol. IV, China Science and Technology Press.
16. Synthesis and Characterisation of Diaryl Furoxans
Sandhya Vyas, M. B. Talawar, R. S. Kusurkar, S. N. Asthana and V. N. Krishnamurthy.
Defence Science Journal 2006, 56, 551-557.
17. Microwave mediated fast synthesis of diaminoglyoxime (DAG), 3,4diaminofurazan (DAF) and 4,4’-diamino-3,3’-azofurazan: key synthons for synthesis of high
energy density materials (HEDMS)
Radhika S Kusurkar, Shailesh K. Goswami, M. B. Talawar, G. M. Gore and S.N.Asthana
Journal of Chemical Research, 2005, 245.
18. Thermal and Microwave-Assisted Conjugate Additions of Indole on Electron
Deficient Nitro-olefins.
Radhika S. Kusurkar, Nabil A. H. Alkobati, Anita S. Gokule, Purnima M.Chaudhari, and
Prasad B.Waghchaure
Synthetic Communications 2006, 36, 1075–1081.
19. Conjugate addition of Pyrroles to α, β–unsaturated ketones using copper bromide
as a catalyst.
Radhika.S.Kusurkar,* Sandip.K.Nayak and Neelam L. Chavan
Tetrahedron Lett. 2006, 47, 7323-7326.
20. An efficient synthesis of bibenzylic oxygen heterocycles.
Virendra B. Kumbhar, Augustine R. Joseph, Arun D. Natu, Radhika S.Kusurkar and
Madhusudan V. Paradkar
Journal of Chemical Research 2007, 590-593.
21. Use of the Pictet-Spengler reaction for the synthesis of new 1,4-disubstituted-1,2,3,4tetrahydro-β-carbolines and 1, 4-disubstituted-β-carbolines: Formation of γ-carbolines.
Radhika S. Kusurkar, Nabil A. H. Alkobati, Anita S. Gokule and Vedavati G. Puranik.
Tetrahedron 2008, 64, 1654-1662.
22. A Combination of AlCl3, Ionic Liquid and MW: An Efficient Method for Dehydration and
1,3-Dipolar Cycloaddition; An Unusual Observation in the Presence of Acrylonitrile.
Radhika S. Kusurkar*, Nilesh H. Naik and Prajakta N. Naik
Synthetic Communications 2008, 38, 1–6.
23. Microwave-assisted conjugate addition of pyrrole on electron-deficient nitro-olefins
Nabil A. H. Alkobati and Radhika S. Kusurkar
Synthetic Communications 2010, 40, 320–327.
24. Indium(iii) chloride: an efficient catalyst for the synthesis of amidoalkyl naphthols
Neelam L. Chavan, Prajakta N. Naik, Sandip K. Nayak,and Radhika S. Kusurkar
Synthetic Communications 2010, 40 (19), 2941.
25. Silica gel, an effective catalyst for the reaction of electron-deficient nitro-olefins
with nitrogen heterocycles
Abdullah M. A. Shumaila and Radhika S. Kusurkar
Synthetic Communications 2010, 40 (19), 2935.
26. A rapid method toward the synthesis of new substituted tetrahydro α-carbolines and αcarbolines
Neelam L. Chavan, Sandip K. Nayak, Radhika S. Kusurkar
Tetrahedron 2010, 66, 1827–1831.
27. An efficient route towards the synthesis of monosubstituted N-aryl amidines from 4,5
dihydro-1,2,4-oxadiazoles
Neelam L. Chavan, Nilesh H. Naik, Sandip K. Nayak and Radhika S. Kusurkar
Arkivoc 2010, ii, 248-255.
28. Diastereoselective synthesis of 1,1,4-trisubstituted-2,3,4,9-tetrahydrospiro-βcarbolines via glacial acetic acid catalyzed Pictet- Spengler reaction
Abdullah M. A. Shumaila, Vedavati G. Puranik and Radhika S. Kusurkar
Arkivoc 2011, (ii), 41-56.
29. Synthesis of tetrahydro-5-azaindoles and 5-azaindoles using Pictet-Spengler reaction –
appreciable difference in products using different acid catalysts
Abdullah M. A. Shumaila and Radhika S. Kusurkar*
Tetrahedron 2011, 67, 936-942.
30. Regio and stereoselective synthesis of new substituted tetrahydrocarbazoles and carbazoles
using Diels Alder reactions.
Dattatray G. Hingane, Shailesh K.Goswami, Vedavati Puranik, and Radhika S. Kusurkar*
Synthetic Communications 2012, 42, 1786-1795.
31. Diastereoselective synthesis of tetrasubstituted-octahydro-3,6 diazacarbazoles and
tetrasubstituted-3,6-diazacarbazoles via double Pictet-Spengler reaction
Abdullah M. A. Shumaila, Vedavati G. Puranik and Radhika S. Kusurkar*
Tetrahedron Letters 2011, 52, 2661-2663.
32. An efficient new route towards biologically active isocryptolepine and γ-carboline
derivatives
using an intramolecular thermal electrocyclization strategy
Dattatray G. Hingane and Radhika S. Kusurkar*
Tetrahedron Letters 2011, 52, 3686–3688.
33. An efficient total synthesis of calothrixin B
Bhosale, S.M., Gawade, R.L., Puranik, V.G., Kusurkar*, R.S.,
Tetrahedron Letters 2012, 53, 2894-2896.
34. New and efficient routes for the synthesis of murrayaquinone A and murrayanine
Shrikar M. Bhosale, Aadil A. Momin, Radhika S. Kusurkar *
Tetrahedron 2012, 68, 6420-6426.
35. A new synthetic route for 1, 2-diketo compounds using unexpected C-C bond cleavage
by PCC
Shrikar M. Bhosale, Aadil A. Momin, Rupesh L. Gawade, Vedavati G. Puranik, Radhika
S. Kusurkar*
Tetrahedron Letters 2012, 53, 5327–5330.
36. AlCl3 as an efficient catalyst towards the synthesis of 1, 6-dihydropyrazine-2,3-dicarbonitrile
Derivatives.
Shrikar M. Bhosale, Nilesh H. Naik & Radhika S. Kusurkar*
Synthetic Communications 2013, 43(23), 3163-3169.
37. Silica gel supported bismuth nitrate pentahydrate - A highly active catalyst under solvent free
conditions towards the synthesis of dihydropyrimidin-2(1H)-ones and their
sulphur analogues
Dattatray G. Hingane, Abdullah M. A. Shumaila and Radhika S. Kusurkar*
Accepted in 2012 for Publication in Indian Journal of Chemistry, Sec.B
In press.
38. Two new approaches towards the synthesis of annomontine using Pictet-Spengler and az a
Diels-Alder reactions.
Nilesh H. Naika, b, Arun K. Sikderb, Radhika S. Kusurkara*
Tetrahedron Letters 2013, 54(28), 3715–3717.
39. Synthesis of canthine analogues using intramolecular Aza-Diels-Alder strategy
and evaluation of their activity against HeLa cervical cancer cells
Prajakta N. Naika, Nilesh H. Naika, Ayesha Khanb, Radhika S. Kusurkara*
Tetrahedron 2013, 69, 6545–6551.
40. Total Synthesis of Bouchardatine
Nilesh H. Naik, Tukaram D. Urmode, Arun K. Sikder, Radhika S. Kusurkar*
Aust. J. Chem, 2013, 66, 1112–1114.
41. Intramolecular Diels-Alder Reaction for the Synthesis of Tetracyclic Carbazoles
and Isocanthines
Prajakta N. Naik, Ayesha Khan, Radhika S. Kusurkar*
Tetrahedron, accepted for Publication.
Reports and books: Nil
Summary of proposed research:
β-Carbolines, as well as γ-carbolines is a big class of compounds containing indole ring. Many of these
alkaloids are naturally occurring and exhibit various biological activities like antitumor activity,
cytotoxicity to tumor cell lines, anthelmintic and antiprotozoal activity, antihypertensive etc. In the
present proposal 1- substituted 3-aza-β-carbolines and 4, 5-disubstituted 6-aza-γ-carbolines would be
synthesized using new routes. Bioactivity evaluation would be carried out and the effect of substituents on
the activity would be studied. Synthetic route would be established for biologically active nostodione A
using one of the intermediates formed in the previous synthetic sequence.