Professor Manas Chakrabarty - Academia.edu (original) (raw)
Papers by Professor Manas Chakrabarty
Zenodo (CERN European Organization for Nuclear Research), Feb 28, 2004
Science and culture, Dec 21, 2022
Experientia, Oct 1, 1976
Summary Reflexine, a new indole alkaloid, has been isolated from the leaves ofRauwolfia reflexa T... more Summary Reflexine, a new indole alkaloid, has been isolated from the leaves ofRauwolfia reflexa Teijsm. and Binn. From spectral studies, chemical reactions and correlation with seredamine, reflexine is shown to be its C-17 epimer (IV).
Science and Culture
was a man of unique combination of virtues and activities. His multi-faceted activities are, to s... more was a man of unique combination of virtues and activities. His multi-faceted activities are, to say the least, captivating. He was the founder of Bengal Chemical and Pharmaceutical Works (BCPW) and (along with Megh Nad Saha) Indian Science News Association. Besides, he was a passionate teacher, a social reformer, a historian of science, a remarkable entrepreneur, a true patriot, 'almost a politician', a linguist, a prolific and bilingual writer and, above all, a selfless philanthropist of austere lifestyle. His valuable contribution to the diverse array of the aforesaid domains fetched him global recognition and reverence. A revisit (in two parts) to the life and work of this great Indian Savant is just a humble tribute of the present author to this monumental personality.
Science and Culture, 2020
Arkivoc, 2017
A new synthesis of pleraplysillin-1, a sponge metabolite, has been accomplished using Wittig olef... more A new synthesis of pleraplysillin-1, a sponge metabolite, has been accomplished using Wittig olefination of 2bromo-1-formyl-4,4-dimethylcyclohex-1-ene with an appropriate ylide. A generalized study on the Wittig olefination of several 2-bromo-1-formyl-1-cycloalkenes with the ylides generated in situ from 2-(3/2furyl)ethyltriphenylphosphonium bromides was also undertaken as a prerequisite. The described methodology is not the most efficient route to the desired isomer. However, it does offer a new route to molecules of type 1, with the advantages that it (i) is relatively simple, (ii) does not involve expensive or toxic organometallic reagents, and (iii) affords overall yields of the bromo analogues and the final diastereoisomeric mixtures, which are much better than those previously reported.
ChemInform, 1989
ChemInform Abstract Heating of the acid (I) in acetic anhydride furnishes, in addition to the anh... more ChemInform Abstract Heating of the acid (I) in acetic anhydride furnishes, in addition to the anhydride (II) which is required as acylating agent, the title compound (III).
ChemInform, 1999
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Phytochemistry, 1972
Three indole alkaloids have been isolated from Alstonia macrophyllu Wall. Two of these have been ... more Three indole alkaloids have been isolated from Alstonia macrophyllu Wall. Two of these have been identified as affinisine (I) and picrinine (II). The third, a new base designatedpicralsronine, has been shown to possess structure (III).
Indian journal of experimental biology, 2001
The herb Desmotrichum fimbriatum Bl. (family: Orchidaceae), sold as Jibanti in West Bengal, is us... more The herb Desmotrichum fimbriatum Bl. (family: Orchidaceae), sold as Jibanti in West Bengal, is used in 'Rasayana therapy' in Ayurveda. Its effect on the modulation of the two antioxidant enzymes peroxidase and catalase has been studied in mice liver during 'cold water swim' (CWS) stress using appropriate controls. The drug, i.e. the aqueous ethanolic extract of the herb (whole plant) was found to increase peroxidase titre in the hepatic cells of normal mice. But in the stressed group, the drug displayed no effect on the peroxidase content, while it elicited an elevation of the catalase content. infinity-Tocoferol was used as the standard drug. These data suggested that the drug can ameliorate the peroxidative damage caused in mice by CWS stress.
Australian Journal of Chemistry, 1975
Two alkamides have been isolated from the leaves of Pleiospermium alatum (Rutaceae). On the basis... more Two alkamides have been isolated from the leaves of Pleiospermium alatum (Rutaceae). On the basis of spectral and chemical evidence the new alkamide, designated alatamide, has been identified as N-(E)-(p- methoxystyryl)benzamide (1). The second compound has been characterized as N-benzoyltyramine methyl ether (2) by hydrolysis experiments and synthesis.
Formerly, Department of Chemistry, Bose Institute, 9311, Acharya Prafulla Chandra Road, Kolkata-7... more Formerly, Department of Chemistry, Bose Institute, 9311, Acharya Prafulla Chandra Road, Kolkata-700 009, India <em>E-mail </em>: chakmanas09@gmail.com Department of Chemistry, Krishnagar Government College, Krishnagar-741 I 01, Nadia, West Bengal, India <em>Manuscript received 05 July 2013. accepted 06 July 2013</em> In order to develop eco-friendly syntheses of condensed nitrogen heterocycles, solvent-free syntheses on solid acidic catalysts and aqueous reactions using a phase transfer catalyst (PTC) were successfully carried out. The catalysts used were (i) TLC-grade silica gel G (SiO<sub>2</sub>), (ii) SiO<sub>2</sub> doped with 10 mol% phosphoric acid (H<sub>3</sub>PO<sub>4</sub>-SiO<sub>2</sub>), (iii) Montmorillonite K10 clay (K10), (iv) acid-washed K10 clay (acid-clay), (v) KIO doped with one equivalent (with respect to substrate) of tosic acid (TsOH-KIO) and (vi) cetylpyridinium bromide (CPB)...
was a man of unique combination of virtues and activities. His multi-faceted activities are, to s... more was a man of unique combination of virtues and activities. His multi-faceted activities are, to say the least, captivating. He was the founder of Bengal Chemical and Pharmaceutical Works (BCPW) and (along with Megh Nad Saha) Indian Science News Association. Besides, he was a passionate teacher, a social reformer, a historian of science, a remarkable entrepreneur, a true patriot, 'almost a politician', a linguist, a prolific and bilingual writer and, above all, a selfless philanthropist of austere lifestyle. His valuable contribution to the diverse array of the aforesaid domains fetched him global recognition and reverence. A revisit (in two parts) to the life and work of this great Indian Savant is just a humble tribute of the present author to this monumental personality.
An unusual and mechanistically interesting product, 15-(1H-indol-3-yl)-1,11,13-trimethyl-12,14-di... more An unusual and mechanistically interesting product, 15-(1H-indol-3-yl)-1,11,13-trimethyl-12,14-dioxa-9-azapentacyclo[11.3.1.1 1 1 , 1 5 .0 2 , 1 0 .0 3 , 8 ]octadeca-2(10), 3,5,7-tetraene (1) has been synthesized from indole and acetylacetone in the presence of boron trifluoride etherate in methylene chloride. Structure 1 was unambiguously established from detailed studies of the HMQC and HMBC spectra along with 1 H and 1 3 C-NMR spectra. The plausible mechanism of the reaction is presented.
Phytochemistry, 1988
... PHASEOLOIDIN, A HOMOGENTISIC ACID GLUCOSIDE FROM ENTADA PHASEOLOI DES ARUN K. BARUA, MANAS CH... more ... PHASEOLOIDIN, A HOMOGENTISIC ACID GLUCOSIDE FROM ENTADA PHASEOLOI DES ARUN K. BARUA, MANAS CHAKRABARTY, PRAM K. DATTA ... AcknowledgementsThe authors are indebted to the RSLC., Bose Institute, Professor UR Ghatak (Indian Association for the ...
Science and Culture, Jan 15, 2020
Science and Culture
The year 2018 marked the birth centenary of the Gandhian mathematician-cum-physicist, P.C. Vaidya... more The year 2018 marked the birth centenary of the Gandhian mathematician-cum-physicist, P.C. Vaidya who was an inspiring teacher, a dedicated populariser of mathematics and the proponent of Vaidya metric, a rare dynamic solution to the space time geometry around radiating stir. Sadly, however, this world famous expert in relativity and cosmology could not become a household name in India and has nearly gone into oblivion. There was hardly any celebration of his birth centenary across India. The life and work of this modest scientist have been presented briefly in this article.
Zenodo (CERN European Organization for Nuclear Research), Feb 28, 2004
Science and culture, Dec 21, 2022
Experientia, Oct 1, 1976
Summary Reflexine, a new indole alkaloid, has been isolated from the leaves ofRauwolfia reflexa T... more Summary Reflexine, a new indole alkaloid, has been isolated from the leaves ofRauwolfia reflexa Teijsm. and Binn. From spectral studies, chemical reactions and correlation with seredamine, reflexine is shown to be its C-17 epimer (IV).
Science and Culture
was a man of unique combination of virtues and activities. His multi-faceted activities are, to s... more was a man of unique combination of virtues and activities. His multi-faceted activities are, to say the least, captivating. He was the founder of Bengal Chemical and Pharmaceutical Works (BCPW) and (along with Megh Nad Saha) Indian Science News Association. Besides, he was a passionate teacher, a social reformer, a historian of science, a remarkable entrepreneur, a true patriot, 'almost a politician', a linguist, a prolific and bilingual writer and, above all, a selfless philanthropist of austere lifestyle. His valuable contribution to the diverse array of the aforesaid domains fetched him global recognition and reverence. A revisit (in two parts) to the life and work of this great Indian Savant is just a humble tribute of the present author to this monumental personality.
Science and Culture, 2020
Arkivoc, 2017
A new synthesis of pleraplysillin-1, a sponge metabolite, has been accomplished using Wittig olef... more A new synthesis of pleraplysillin-1, a sponge metabolite, has been accomplished using Wittig olefination of 2bromo-1-formyl-4,4-dimethylcyclohex-1-ene with an appropriate ylide. A generalized study on the Wittig olefination of several 2-bromo-1-formyl-1-cycloalkenes with the ylides generated in situ from 2-(3/2furyl)ethyltriphenylphosphonium bromides was also undertaken as a prerequisite. The described methodology is not the most efficient route to the desired isomer. However, it does offer a new route to molecules of type 1, with the advantages that it (i) is relatively simple, (ii) does not involve expensive or toxic organometallic reagents, and (iii) affords overall yields of the bromo analogues and the final diastereoisomeric mixtures, which are much better than those previously reported.
ChemInform, 1989
ChemInform Abstract Heating of the acid (I) in acetic anhydride furnishes, in addition to the anh... more ChemInform Abstract Heating of the acid (I) in acetic anhydride furnishes, in addition to the anhydride (II) which is required as acylating agent, the title compound (III).
ChemInform, 1999
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Phytochemistry, 1972
Three indole alkaloids have been isolated from Alstonia macrophyllu Wall. Two of these have been ... more Three indole alkaloids have been isolated from Alstonia macrophyllu Wall. Two of these have been identified as affinisine (I) and picrinine (II). The third, a new base designatedpicralsronine, has been shown to possess structure (III).
Indian journal of experimental biology, 2001
The herb Desmotrichum fimbriatum Bl. (family: Orchidaceae), sold as Jibanti in West Bengal, is us... more The herb Desmotrichum fimbriatum Bl. (family: Orchidaceae), sold as Jibanti in West Bengal, is used in 'Rasayana therapy' in Ayurveda. Its effect on the modulation of the two antioxidant enzymes peroxidase and catalase has been studied in mice liver during 'cold water swim' (CWS) stress using appropriate controls. The drug, i.e. the aqueous ethanolic extract of the herb (whole plant) was found to increase peroxidase titre in the hepatic cells of normal mice. But in the stressed group, the drug displayed no effect on the peroxidase content, while it elicited an elevation of the catalase content. infinity-Tocoferol was used as the standard drug. These data suggested that the drug can ameliorate the peroxidative damage caused in mice by CWS stress.
Australian Journal of Chemistry, 1975
Two alkamides have been isolated from the leaves of Pleiospermium alatum (Rutaceae). On the basis... more Two alkamides have been isolated from the leaves of Pleiospermium alatum (Rutaceae). On the basis of spectral and chemical evidence the new alkamide, designated alatamide, has been identified as N-(E)-(p- methoxystyryl)benzamide (1). The second compound has been characterized as N-benzoyltyramine methyl ether (2) by hydrolysis experiments and synthesis.
Formerly, Department of Chemistry, Bose Institute, 9311, Acharya Prafulla Chandra Road, Kolkata-7... more Formerly, Department of Chemistry, Bose Institute, 9311, Acharya Prafulla Chandra Road, Kolkata-700 009, India <em>E-mail </em>: chakmanas09@gmail.com Department of Chemistry, Krishnagar Government College, Krishnagar-741 I 01, Nadia, West Bengal, India <em>Manuscript received 05 July 2013. accepted 06 July 2013</em> In order to develop eco-friendly syntheses of condensed nitrogen heterocycles, solvent-free syntheses on solid acidic catalysts and aqueous reactions using a phase transfer catalyst (PTC) were successfully carried out. The catalysts used were (i) TLC-grade silica gel G (SiO<sub>2</sub>), (ii) SiO<sub>2</sub> doped with 10 mol% phosphoric acid (H<sub>3</sub>PO<sub>4</sub>-SiO<sub>2</sub>), (iii) Montmorillonite K10 clay (K10), (iv) acid-washed K10 clay (acid-clay), (v) KIO doped with one equivalent (with respect to substrate) of tosic acid (TsOH-KIO) and (vi) cetylpyridinium bromide (CPB)...
was a man of unique combination of virtues and activities. His multi-faceted activities are, to s... more was a man of unique combination of virtues and activities. His multi-faceted activities are, to say the least, captivating. He was the founder of Bengal Chemical and Pharmaceutical Works (BCPW) and (along with Megh Nad Saha) Indian Science News Association. Besides, he was a passionate teacher, a social reformer, a historian of science, a remarkable entrepreneur, a true patriot, 'almost a politician', a linguist, a prolific and bilingual writer and, above all, a selfless philanthropist of austere lifestyle. His valuable contribution to the diverse array of the aforesaid domains fetched him global recognition and reverence. A revisit (in two parts) to the life and work of this great Indian Savant is just a humble tribute of the present author to this monumental personality.
An unusual and mechanistically interesting product, 15-(1H-indol-3-yl)-1,11,13-trimethyl-12,14-di... more An unusual and mechanistically interesting product, 15-(1H-indol-3-yl)-1,11,13-trimethyl-12,14-dioxa-9-azapentacyclo[11.3.1.1 1 1 , 1 5 .0 2 , 1 0 .0 3 , 8 ]octadeca-2(10), 3,5,7-tetraene (1) has been synthesized from indole and acetylacetone in the presence of boron trifluoride etherate in methylene chloride. Structure 1 was unambiguously established from detailed studies of the HMQC and HMBC spectra along with 1 H and 1 3 C-NMR spectra. The plausible mechanism of the reaction is presented.
Phytochemistry, 1988
... PHASEOLOIDIN, A HOMOGENTISIC ACID GLUCOSIDE FROM ENTADA PHASEOLOI DES ARUN K. BARUA, MANAS CH... more ... PHASEOLOIDIN, A HOMOGENTISIC ACID GLUCOSIDE FROM ENTADA PHASEOLOI DES ARUN K. BARUA, MANAS CHAKRABARTY, PRAM K. DATTA ... AcknowledgementsThe authors are indebted to the RSLC., Bose Institute, Professor UR Ghatak (Indian Association for the ...
Science and Culture, Jan 15, 2020
Science and Culture
The year 2018 marked the birth centenary of the Gandhian mathematician-cum-physicist, P.C. Vaidya... more The year 2018 marked the birth centenary of the Gandhian mathematician-cum-physicist, P.C. Vaidya who was an inspiring teacher, a dedicated populariser of mathematics and the proponent of Vaidya metric, a rare dynamic solution to the space time geometry around radiating stir. Sadly, however, this world famous expert in relativity and cosmology could not become a household name in India and has nearly gone into oblivion. There was hardly any celebration of his birth centenary across India. The life and work of this modest scientist have been presented briefly in this article.