Avijit Banerji

Avijit Banerji
University of Calcutta · Department of Chemistry

Doctor of Philosophy

About

84
Publications
5,417
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658
Citations
Citations since 2016
17 Research Items
129 Citations
201620172018201920202021202205101520
201620172018201920202021202205101520
201620172018201920202021202205101520
201620172018201920202021202205101520

Publications

Publications (84)
Article
Full-text available
Objective: We report the phyto-pharmacognostic evaluation and HPTLC fingerprinting profile of the methanolic extract of Saptaparṇa [Alstonia scholaris (L.) R. Br.] leaves-unaffected and gall-affected, collected in January 2019. Materials and Methods: Physicochemical parameters and phytochemical screening were done by standard procedures. HPTLC fing...
Article
Full-text available
Viral diseases, including the emerging (COVID-19) and chronic viruses, are causing increasing worldwide health concerns. Consequently, the discovery of new antiviral agents from plants has assumed more urgency than in the past. A number of indigenous Indian drugs of plant origin are known to have antimicrobial and anti-inflammatory activity, althou...
Article
Full-text available
Investigations of [3+2] cycloadditions of C,N-diaryl and C-aryl-N-methyl nitrones as three atom components (TAC) to substituted methyl E-cinnamates and diethyl arylidene malonates have been further investigated. [3+2] Cycloadditions of cinnamates yielded mixtures of cycloadducts, the major products being the 3,4-trans-4,5-trans-2,3,5-triaryl-4-carb...
Article
Full-text available
Plants are rich sources of bioactive compounds, and have been used in traditional medicine systems for the past few millennia; even now plant-based drugs continue to provide new remedies to mankind. The medicinal plant Alstonia scholaris (L.) R. Br. (Saptaparṇa, Chhatim) is widely used in the Indian school of traditional medicine of Ayurveda. The p...
Preprint
Full-text available
A new steroid, designated Alru-1, isolated from the hexane extract of Ailanthus excelsa Roxb, has been characterised from spectroscopic analysis and chemical transformation as stigmasta-4, 22-dien-3-ol.
Article
Full-text available
Investigations of the cycloaddition of C-(4-chlorophenyl)-N-phenyl nitrone to substituted cinnamic acid anilides were carried out. The predominant product in each reaction was the 3,4-trans-4,5-trans-4-carboxanilido-2,3,5-triaryl isoxazolidine cycloadduct, with much smaller amounts of the diastereoisomeric 3,4-cis-4,5-trans-4-carboxanilido-2,3,5-tr...
Article
Cycloaddition reaction of N-phenyl-a-amino nitrone to methyl vinyl ketone generates stereospecific isoxazolidine possessing antibacterial properties. In the present report, detailed theoretical study at DFT/B3LYP/6-311G + (d,p) level of theory has been carried out to analyze the preferred regio- and stereospecific mode of the reaction. Global prope...
Article
Chemical investigation of Hemidesmus indicus roots yielded α-amyrin acetate, β-amyrin acetate, taraxesteryl acetate and a new triterpenoid designated hemidesterpene. The latter was characterised as Δ12,l3-taraxcsteryl acetate from spectrosopical investigations.
Article
Dipolar cycloaddition reactions of chalcones with non-stabilized azomethine ylides formed in situ from L-proline and aldehydes are studied.
Article
Full-text available
Simple and efficient strategies towards the synthesis of tri-substituted pyrrolizidines and di-substituted oxazolidine systems by 1,3-dipolar cycloaddition reactions utilising arylaldehydes and α-amino acids have been developed, followed by one-pot three component strategy. Electron-deficient dipolarophile, chalcones were reacted with nonstabilized...
Article
Full-text available
Simple and efficient strategies towards the synthesis of substituted spiro-oxindole and oxazolidine systems by one-pot multi-component catalyst-free reactions utilising aryl aldehydes and α-amino acids have been developed. Owing to their complicated structure and ring strain spiro-oxindole moieties are not easily synthesised. In either route 1,3-di...
Article
A facile route to tetra-substituted pyrrolidines has been accomplished by 1,3-dipolar cycloaddition reaction. Several pyrrolidine compounds have significant biological activity. A highly electron-deficient dipolarophile, β-nitrostyrene, was reacted with nonstabilized azomethine ylides derived from aryl aldehyde and L-phenylglycine in dry dimethyl f...
Article
Azomethine ylides derived in situ from l-proline and aryl aldehydes underwent regioselective and stereoselective cycloadditions with diaryl cycloahexanone to form a series of spiro-pyrrolizidine compounds. By using equimolar proportions of the reactants in DMF, only a single mono-adduct, namely 6′-arylidene-1-aryl-3-aryl-spiro[pyrrolizidine-2,2′-cy...
Article
Full-text available
Solution phase multi-component synthetic strategy was utilized to synthesize trisubstituted pyrrolizidines. The key step was the ring-forming 1,3-dipolar cycloaddition of non-stabilized azomethine ylides generated in situ with electron-deficient dipolarophiles. Characterization of cycloadducts were done by detailed spectroscopic analysis, and final...
Article
1,3-Dipolar cycloaddition reactions of nitrones to substituted olefins give rise to synthetically useful isoxazolidines with up to three new chiral centers. The preferred regio- and stereochemical mode of approach of the dipolarophile over the dipole controls the selectivities of such reactions. These can be rationalised by DFT based theoretical mo...
Article
The preferred configurations and conformations of C-aryl-N-phenyl nitrones have been predicted theoretically by detailed comparison of DFT/B3LYP/6- 311+G(2d,p) calculated gauge invariant atomic orbital nuclear magnetic shielding tensors and experimentally recorded chemical shift values. The frontier molecular orbital energies, electronic chemical p...
Article
Molecular orbital calculations have been performed by DFT calculations using B3LYP theory and 6-31 G (d) level of approximation for C-(4-chlorophenyl)-N-methyl nitrone on the basis of its optimised geometry. The effect of substitutions on orbital energies have been deduced by comparison to other nitrones and 1,3-dipoles.
Article
A new carbazole alkaloid (kurryam) oxygenated at the 4-position, hitherto unknown among carbazole alkaloids, has been isolated from the seeds of an Indian medicinal plant, Murraya koenigii (Rutaceae). The structure has been established as 4-hydroxy-(2′,2′,3)-trimethyl-(6,7)-dimethoxy pyranocarbazole from extensive 2D NMR spectral studies. In additi...
Article
Full-text available
Investigation of the stem of Paederia foetida (Rubiaceae) resulted in the isolation and characterization of N-(4-methylphenyl)-benzopropanamide, which was hitherto unknown as a natural product This is the first report of an amide for the genus Paederia.
Article
This review outlines some recent developments in 1,3-dipolar cycloadditions of nitrones. An attempt has been made to focus on aspects which were comparatively less revealed earlier. Special emphasis has been given on reactions and their explanation on mechanistic and theoretical grounds, rather than on applications.
Article
Some recent developments on 1,3-dipolar cycloadditions of nitrones are reviewed with particular reference to the work carried out in our research group. We investigated the cycloadditions of C-aryl-TV-phenylmtrones and C-aryl-N-methylnitrones to substituted cinnamic acid piperidides with reference to regioselectivity and stereoselectivity of the pr...
Article
Cycloaddition reactions of 1-phenyl-3-oxidopyridinium betaine with a number of 1,2-disubstituted olefins bearing electron-withdrawing groups have been investigated. The regio- and stereochemical preferences of the cycloaddition processes have been studied. A Michael addition product derived from a cycloadduct isalso obtained in addition to the cycl...
Article
Cycloaddition reactions of 1-phenyl-3-oxidopyridinium betaine with a number of 1,2-disubstituted olefins beating electron-withdrawing groups have been investigated. The regio- and stereochemical preferences of the cycloaddition processes have been studied. A Michael addition product derived from a cycloadduct is also obtained in addition to the cyc...
Article
The action of thallium(III) acetate on a number of indoles, differently substituted in the 2- and 3-positions, has been investigated. Monomeric and 'dimeric' oxidation products are obtained; the structures of the products depend on the substituents present in the substrate. A novel oxidative dimerisation of 2,3-disubstituted indoles to indolo[3,2-b...
Article
Full-text available
The cycloaddition reactions of three C,N-diarylnitrones 1-3 to N-cinnamoylpiperidines have been investigated. The all-trans-5-aryl-4-piperidinyloxoisoxazolidines are obtained regio- and stereoselectively as the major products with the corresponding 3,4-cis isomers as minor cycloadducts. Structures and stereochemistry of the products have been deter...
Article
Full-text available
Cycloaddition of 1-pyrroline 1-oxide 1 to 1-cinnamoylpiperidine 2 and 1-(4′-chlorocinnamoyl) piperidine 3 gives two regioisomeric cycloadducts in each case. The structure and stereochemistry of the cycloadducts have been confirmed from spectroscopic and X-ray crystallographic analysis.
Article
Reactions of several nitrogen heterocycles with sodium naphthalenide in aprotic solvents were investigated. The reactions were quenched with an aqueous buffer. Quinoline reacted by the single-electron transfer pathway to give a ‘dimeric’ (3), a ‘trimeric’ product (4) and 4-quinolone. 4-Quinazolinone afforded a single ‘dimeric’ product (9). Reaction...
Article
The cycloadditions of four C,N-diaryl nitrones (1–4) to the 5-membered conjugated lactone 2-butenolide were investigated. Two stereoisomeric 2-phenyl-3-aryl-2,3,6,6a-tetrahydrofuro[3,4-]-isoxazol-4(3a)-one cycloadducts and a ring-opened butanolide derivative were obtained in each case. The structure and stereochemistry of the products were determin...
Article
13C NMR data for several 1-substituted prop-2-ynes and 1,4-bis derivatives of but-2-yne are reported with full assignments. Substituent effects of —X—aryl groups (X = O, S, NMe, SO2) at the propargylic position on the chemical shifts of the acetylenic carbons were determined.
Article
Two new unsaturated amides, brachystamides-A and B, were isolated from the total above-ground parts of Piper brachystachyum. Brachystamide-A was shown to be N-isobutyl-15 (3′,4′-methylenedioxyphenyl) 2E,4E-pentadecadienamide from spectroscopic and chemical investigations. Brachystamide-B was N-isobutyl-15 (3′,4′-methylenedioxyphenyl) 2E,4E,14E-pent...
Article
The cinnamic acid piperidides (I) are treated with sodium naphthalenide to form the stereoisomeric piperidides (II) and (III) via reductive dimerization, together with the dihydro derivatives (IV).
Article
13C NMR data for 1,6-bis derivatives of hexa-2,4-diynes are reported. Introduction of a sulphone or sulphoxide moiety at C-1, C-6 in place of sulphide, ether or amino groups caused a 6–7 ppm upfield shift (β effect) for the C-2, C-5 carbons and a 3–4 ppm downfield shift (y effect) for the C-3, C-4 carbons.
Article
Reaction of coumarin (I) with thallium(III) nitrate trihydrate in dry methanol (II) gives 6-nitro-3-methoxycoumarin (III).
Article
The reactions of several coumarins with thallium (III) salts have been investigated. The compounds isolated were usually oxidation products derived from initially formed organometallics.
Article
Aus den beiden Oximen (I) hergestellte kondensierte Isoxazole (II) werden in die Salze (III) übergeführt, die mit Diisopropyl-ethyl-amin zu den Azetinonen (IV) führen.
Article
13C NMR spectra of Piper alkamides and related compounds have been completely assigned on the basis of splitting patterns in the coupled spectra, application of additivity relationships and internal comparison of chemical shifts.
Article
Chemical and spectral evidence for the formation of azetinones 11a-d is presented.
Article
The structure, N-isobutyl-4,5-dihydroxy-2(E)-decenamide, for sylvamide is confirmed by its total synthesis. The erythro stereochemistry is also established by comparison of the properties of the natural and synthetic samples.
Article
Aus dem Iminodicarbonsäurechlorid (I) werden mit den Chinazolonen ( II) die Hexacyclpn (III) und mit den Amidinen (IV) die Tetracyclen (V) hergestellt.
Article
Amidines react with diphenylamine-2,2′-dicarbonyl chloride to yield polyheterocycles Reactions of some of the latter with reducing agents are also reported.
Article
Sylvamide, a new amide derivative, has been isolated from the petrol extract of the seeds of Piper sylvaticum (Roxb.). From spectral and chemical s
Article
Two new amides, aurantiamide and aurantiamide acetate, were isolated from Piper aurantiacum. Their structures were determined as N-(N′-benzoyl-S-phenylalaninyl)-S-phenylalaninol and its acetate, respectively, from chemical and spectroscopic studies. The structures and stereochemistry were confirmed by synthesis. The corresponding diastereoisomers w...
Article
A new alkaloid designated scholarine was isolated from the leaves of Alstonia scholaris. It was (±) 12-methoxyechitamidine as determined by chemical and spectroscopic investigations.
Article
13C NMR of diastereoisomeric pairs of 2,3-diaryl-2-methylbutyronitriles revealed a difference in the chemical shift of the carbon atoms between the diastereoisomers and the observed shifts were greatly influenced by the presence of an ortho substituent in the 3-phenyl ring.
Article
13C NMR spectra of six kawa-pyrones (styryl α-pyrones) have been assigned. The assignments are based on the splitting pattern in the coupled spectra, comparison of the chemical shifts with those of model compounds and by application of additivity relationships. The 13C NMR of styrene was also reinvestigated.
Article
Osthol (II) bildet bei der Behandlung mit wasserfreiem A1-trichlorid in siedendem Toluol die 7-Hydroxy-8-isopentylcumarine (III).
Article
Kinetic rates are determined for the transfer of N-benzyl, methyl, and ethyl groups from a pyridinium cation to a substituted pyridine. Rates (and equilibrium constants) vary significantly with alkyl group, nucleophilicity of the substituted pyridine, and with solvent. Transfer rates for methyl and ethyl depend on the anion showing that the corresp...
Article
Die Oxidation von Indolen mit Tl(III)-acetat f?hrt sowohl zu monomeren (3-Acetoxy-indol aus Indol, 3-Methyl- und 3-Acetoxy-3-methyl-oxindol aus 3-Methyl-indol) als auch zu dimeren Reaktionsprodukten, wie z.B. einem Indoxylindol aus 2-Methyl-indol und den Tetrahydroindolocarbazolen (II) aus den Indolen (I).
Article
A new alkaloid, majvinine, was isolated from aerial parts of Vinca major. Its structure was determined by chemical and spectroscopic investigations
Article
Benzimidazole undergoes reversible dearomatisation with 2,2′-iminodibenzoyl chloride to yield a triazahexacyclic compound (8a). Analogous cyclisations succeeded with 5,6-dimethylbenzimidazole and 4-quinazolone, and with acyclic amidines. Imidazole itself yields the diazocine derivative (19).
Article
Das aus 2-Hydroxy-4-methoxybenzaldehyd (I) erhältliche Osthol (II) liefert durch Epoxidierung mit m-Chlorperbenzoesäure das Epoxid (III), aus dem durch Behandlung mit Bortrifluoridätherat in Dioxan bei 50°C in ca. 80%iger Ausbeute das Cumarinderivat (IV) neben 10% Isoaurapton (V) erhalten wird.
Article
Die Kondensation von (-)-L-N-Benzoyl-phenylalanin mit (-)-L-Phenylalaninol in Gegenwart von Dicyclohexylcarbodiimid ergibt Aurantiamid (Ia), das mit Acetanhydrid in Pyridin zu (Ib) acetyliert wird.
Article
A monoterpenoid pyridine derivative isolated from the aerial parts of Indian Vinca major L. has been identified as RW 47 (Venoterpine), previously obtained from an Alstonia and a Rauwolfia species, on the basis of spectral evidence and by direct comparison.
Article
Five indole alkaloids have been isolated from the aerial parts of Vinca major. Four of these have been identified as reserpinine (pubescine), vincamajoreine, majoridine and 10-methoxyvellosimine. The fifth base, a new indole alkaloid lochvinerine, has been assigned the depicted structure.
Article
Spektroskopische Strukturaufklrung eines Inhaltsstoffes (Alkaloid) ausPiper sylvaticum Roxb. mit teils synthetischer Beweisfhrung.
Article
The structure of sylvatine (1), a new alkamide from Piper sylvaticum, has been elucidated from spectroscopic studies, chemical reactions and correlation with compounds of known structures.
Article
Three indole alkaloids have been isolated from Alstonia macrophylla Wall. Two of these have been identified as affinisine (I) and picrinine (II). The third, a new base designated picralstonine, has been shown to possess structure (III).
Article
Chemical investigation of Rhazya stricta Decaisne has led to the isolation of more than a dozen indole alkaloids. Two more indolic bases, rhazinine and R1, obtained from this plant, were shown to be identical with antirhine and geissoschizine respectively. The biogenetic significance of the occurrence of the latter is discussed. Four other minor in...

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