Parthasarathi Das

Indian Institute of Technology (ISM) Dhanbad | ISM · Department of Applied Chemistry

The unmet medical need for the treatment of cancer continues to challenge the biomedical reearch community. The advent of targeted therapy significantly improved therapeutic outcomes. Drug discovery and development efforts...

An efficient and practical method for the N‐alkynylation of 7‐azaindoles has been established by using CuI/DMAP catalytic system at room temperature and in open air. This simple protocol has been successfully employed in the synthesis of a wide range of N‐alkynylated 7‐azaindoles with good yields. Also, this approach is well‐suited for large‐scale...

In this study, an efficient method for hydrogenation reactions has been reported in a short reaction time using a two-chamber reactor. This process involves the ex-situ generation of H2 gas using aluminium-water in the presence of NaOH. This technique was applied to reduce various functional groups, including carbonyl, nitro, alkene, alkyne, and az...

A phosphine-free, efficient protocol for aminocarbonylation and carbonylative Suzuki–Miyaura coupling has been developed using a novel palladium complex, [PdII(DMAP)2(OAc)2]. The complex was successfully synthesized using a stoichiometric reaction between PdII(OAc)2 and DMAP in acetone at room temperature and characterized using single-crystal X-ra...

An efficient and practical N-arylation of hydantoins with substituted aryl/heteroaryl boronic acids has been established, assisted by CuF2/MeOH under the base and ligand-free conditions at room temperature and open air. The protocol is general, and various N-arylated hydantoins have been prepared in excellent yields with exclusive regioselectivity....

There is a continuing demand of new inhibitors of HIV-1 Integrase (HIV-1 IN) due to mutations of HIV-1. This study aims to develop the synthesis of 3,6-diaryl 7-azaindoles and introspect the role of aryl groups on the strand transfer (ST) inhibition of HIV-1 IN. An efficient and chemo-selective one-pot method is established for the synthesis of the...

Multiple spectroscopic techniques, along with single‐crystal X‐ray analysis, have been used to reveal the detailed structural and electronic information on reaction intermediates of a new copper(II)‐DBU catalytic system for the N‐arylation of 7‐Azaindole. The reaction mixture of Chan‐Lam cross‐coupling yields two dimeric copper(II)‐7‐azaindole comp...

CuF2/DMAP has been established as an excellent catalytic system for vinylsilane-promoted N-vinylation of amides and azoles at room temperature without an external fluoride source. A mechanism has been proposed on the basis of the isolation of reactive intermediate [Cu(DMAP)4Cl2], fluoride ion-assisted transmetalation, and ultraviolet-visible spectr...

The carbonyl group forms an integral part of several drug molecules and materials; hence, synthesis of carbonylated compounds remains an intriguing area of research for synthetic and medicinal chemists. Handling toxic CO gas has several limitations; thus, using safe and effective techniques for in or ex situ generation of carbon monoxide from nonto...

The 7‐azaindole is an important building block in several pharmaceutically important compounds. To develop synthetic, elegant techniques for the functionalization of 7‐azaindole core continues to be an active area of research due to its powerful medicinal properties. There have been significant advances in metal‐catalyzed functionalization of the 7...

Herein, we report an efficient DTBP promoted and NaI-catalyzed, greener protocol for the synthesis of highly substituted pyrazoles via C(sp²)–H bond functionalization. This protocol is general and the reaction efficacy improves significantly with the combined use of solvents t-BuOH and EtOH, producing a vast variety of substituted pyrazoles in good...

Deaminative modifications of purines via diazonium chemistry have long been the cornerstone in modified nucleoside synthesis. The purpose of this review is to bring into focus the impact of dediazoniative methods such as non‐aqueous Sandmeyer halogenations, fluorination, arylation and carbon‐heteroatom bond formations on natural purines and their n...

Transition-metal based carbon-heteroatom (C-X) bond formation has attracted the attention of synthetic chemists over the past few years because the resultant aryl/heteroaryl motifs are important substructures in many natural products, pharmaceuticals, etc. Several efficient protocols such as Buchwald-Hartwig amination, Ullmann coupling, Chan-Lam co...

Among the known aromatic nitrogen heterocycles, pyrrole represents a privileged aromatic heterocycle ranging its occurrence in the key component of "pigments of life" to biologically active natural products to active pharmaceuticals. Pyrrole being an electron-rich heteroaromatic compound, its predominant functionalization is legendary to aromatic e...

Phenanthridine derivatives are one of the most intensively studied families of biologically active compounds. There has been considerable scientific interest in the turn of this century in the synthesis of these N‐containing heterocycles as they are prevalent in many alkaloids and also possess striking biological activities including antibacterial,...

Sequence-specific C-arylation strategies have important applications in medicinal and material research. These strategies allow C-C bond formations in a regioselective manner to synthesize large molecular libraries for studying structure-activity profiles. The past decade has seen the development of single C-C bond forming reactions using various t...

Copper-mediated carbon–heteroatom bond-forming reactions involving a wide range of substrates have been in the spotlight for many organic chemists. This review highlights developments between 2010 and 2019 in both stoichiometric and catalytic copper-mediated reactions, and also examples of nickel-mediated reactions, under modified Chan–Lam cross-co...

An efficient coupling method between sulfonylhydrazones and 7‐azaindoles using Pd(OAc)2 as catalyst and dppf as ligand providing flexible and convergent access to different vinyl 7‐azaindoles is achieved. A wide variety of olefins were obtained up to 86% yields via the coupling of numerous electronically distinct hydrazones with different 7‐azaindo...

The 7-azaindole building block has attracted considerable interest in the field of drug discovery in the current portfolio. Because of their powerful medicinal properties, the development of synthetic, elegant techniques for the functionalization of 7-azaindoles continues to be an active area of research. Advances in metal-catalyzed chemistry have...

DABSO mediated sulfonylation of iodinated 7-azaindoles was achieved for the first time through sulfonylative Suzuki-Miyaura cross coupling (SMC) reaction under mild conditions giving good yields of sulfonylated 7-azaindole derivatives. Interestingly, control experiments suggest that present method involves in-situ generation of ArSO2 free radical f...

The synthesis of Imidazo[1,2-a]pyridine-3-carboxamides has been carried out by aminocarbonylation using chloroform as carbon monoxide surrogate. Reported protocol is simple, efficient, tolerates wide variety of substrates and the products were formed in good yields. The method can be exploited for the functionalisation of wide range of N-heterocycl...

Benzoylhydrazone Schiff base–ligated three new ONO pincer–type palladium(II) complexes, [(PdL¹(PPh3)] (1), [(PdL²(PPh3)] (2), and [(PdL³(PPh3)] (3), were synthesized by the reaction of the respective ligand, N‐(2‐hydroxybenzylidene)benzohydrazide (HL¹), N‐(2‐hydroxy‐3‐methoxybenzylidene)benzohydrazide (HL²), or N‐(5‐bromo‐2‐hydroxybenzylidene) benz...

Pd-catalyzed synthesis of multi-aryl 7-azaindoles using sequential arylation of 5-bromo-6-chloro-3-iodo-1-methyl-1H-pyrrolo[2,3-b] pyridine is established. Four diverse aryl groups are installed in chemo-selective fashion providing a general method to synthesize sterically encumbered compounds and extended 7-azaindoles in 48 – 95% yield. Three sele...

Carbonyl moiety is one of the indispensable sub-unit in organic synthesis with significant applications in medicinal as well as material chemistry. Hence the insertion of carbonyl group via simple and highly efficient route has been one of the most challenging tasks for organic chemists. Though the direct utilisation of CO gas in carbonylation is t...

Transition-metal-catalyzed programmed sequential arylation reactions of 2-chloro-4-nitro-1H-imidazole were achieved. The methods are general and were applied in a chemoselective manner for the synthesis of different multiarylated 4-nitroimidazoles bearing three different...

A practical synthesis of diarylpyrazolo[3,4-b]pyridine derivatives by a combination of chemoselective Suzuki-Miyaura cross-coupling reactions was developed. The sequential arylation strategy can be performed in a one-pot manner without much loss of efficiency when compared to the corresponding stepwise synthesis. These conditions are applicable to...

Palladium-catalyzed aminocarbonylation strategy exploiting chloroform as CO surrogate has been developed for the synthesis of biologically potent 2-amidoimidazopyridine scaffolds. The aminocarbonylation reaction was found to be general with a range...

Pyrido[1,2-a]benzimidazole is one of the most important azaheterocyclic compounds consisting of three fused aromatic rings. Molecules containing this core have displayed a wide range of applications in the field of medicinal chemistry. The synthesis of pyrido[1,2-a]benzimidazole and its derivatives has attracted organic chemists because of its trem...

The present protocol describes an efficient, metal-free regioselective synthesis of 2-aroyl-3-arylimidazo[1,2-a]pyridines from 1,3-diaryl-prop-2-en-1-one and 2-aminopyridine. The iodine-NH4OAc promoted reaction offers a novel route in the synthesis of 2-aroyl-3-arylimidazo[1,2-a]pyridines. This protocol...

An environment benign process has been developed for the regioselective synthesis of 5-iodo-1,4-disubstituted-1,2,3-triazoles catalyzed by CuI/β-CD in water. Moreover, the process was manifested for the efficient synthesis of 2-iodo-imidazo[1,2-a]pyridines and 2-iodo-benzoimidazo[2,1-b]thiazoles in aqueous medium. Additionally, the iodinated deriva...

Correction for ‘Cu( i )-catalyzed double C–H amination: synthesis of 2-iodo-imidazo[1,2- a ]pyridines’ by Divya Dheer et al. , RSC Adv. , 2016, 6 , 38033–38036.

A palladium-catalyzed aminocarbonylation of halo-substituted 7-azaindoles utilizing CHCl3 as the carbonyl source has been developed for a straightforward incorporation of amide functional group. The protocol was extended to other heteroarenes...

An efficient Ru(II)-catalyzed site-selective C-H arylation of 2-pyridones and 1-isoquinolinones was achieved with boronic acids by using pyridine as directing group. The developed protocol is general and provides rapid access to an array of C6-arylated 2-pyridones and C3-arylated 1-isoquinolinones in excellent yields. These designed arylated 2-pyri...

A new method for the divergent synthesis of two different pyran-annulated polyheterocycles, indeno[1,2,3-de]chromenes and pyrano[2,3-c]carbazoles from common intermediate has been described. The indeno[1,2,3-de]chromenes class of compounds have been synthesized via Pd-catalyzed cross-dehydrogenative coupling using Oxone as terminal oxidant at room...

Seven unknown impurities in Repaglinide bulk drug batches at below 0.1% (ranging from 0.05-0.10%) were detected by an ultra-performance liquid chromatographic (UPLC) method. These impurities were isolated from the crude sample of Repaglinide using preparative high performance liquid chromatography (prep-HPLC). Based on LC-ESI/MS study, the chemical...

A nickel-catalyzed cross-coupling reaction between methoxy-substituted carbazoles and MeMgBr has been developed. This protocol for the cleavage of the C(aryl)−OMe was used to efficiently assemble various methyl-substituted carbazoles and successfully applied to the total synthesis of the antitumor agent ellipticine.

The reaction has a good functional group tolerance.

A complementary set of Ni- and Cu-based catalyst systems for the selective N-arylation of 2-aminobenzimidazoles have been developed. Selective N-arylation of the primary amine (C-NH2) group was achieved by Ni-catalyzed, boronic acid promoted cross-coupling reactions in air, whereas, selective N-arylation of the azole nitrogen was achieved with Cu-c...

A novel protocol for cobalt(II)-catalyzed synthesis of 2-arylimidazo[1,2-a]pyridines and 3-arylimidazo[1,2-a]pyridines via direct C-N bond formation has been developed. This ligand- and base-free oxidative process is regioselective and having good functional group tolerability. This annulations reaction probably involves a Co(II)/Co(III) catalytic...

A variety of 2-iodo-imidazo[1,2-a]pyridines (III) is synthesized by a copper-catalyzed reaction of 2-aminopyridines with terminal alkynes and iodine.

The selective N-arylation of heterocycles with a series of arylboronic acids under base free conditions at ambient atmosphere is presented.

An unprecedented Pd/Ag synergistic catalysis in the direct carbonylation of C(sp(2))-H bonds utilizing DMF as the carbon source under oxygen is described and demonstrated in the synthesis of pyrido-fused quinazolinone and phenanthridinone scaffolds. Control experiments indicated that the "C" of the carbonyl group is derived from the methyl group of...

A copper(II)‐catalyzed selective CNH 2 arylation of 2‐aminobenzimidazoles and related C‐amino‐NH‐azoles was achieved in presence of 2,2′‐bipyridine and cesium carbonate at 60 °C under open air conditions and this is first method for the copper‐catalyzed selective CNH 2 arylation in the presence of other reactive nucleophilic sites. Previously une...

The title reaction is catalyzed by Pd(OAc)2 and uses Cu(OTf)2 as an oxidative cocatalyst and molecular oxygen as the terminal oxidant.

Iodine/CuI mediated double oxidative C-H amination reaction has been developed for the synthesis of 2-iodo-imidazo[1, 2-a]pyridines. The salient features of this methodology are mild reaction conditions and high regioselectivity. The designed compounds (e.g. 3e) can be served as an active pharmaceutical ingredients (APIs) of marketed drugs like sar...

An expeditious, one-pot, N-iodosuccinimide-promoted reaction has been developed for the synthesis of 3-aroylimidazo[1,2-a]pyridines from 3-phenylpropiolaldehyde and 2-aminopyridines.This aminooxygenation process of alkynes is general and was successfully extended to access 3-aroylimidazo[1,2-a]pyrazines and 3-aroylimidazo[1,2-b]pyridazines. With th...

A general and mild strategy has been developed for the selective N-arylation of tautomerizable heterocycles with a series of arylboronic acids, using CuOTf as the catalyst and 1,10-Phen as the ligand, under base free conditions at ambient atmosphere. The reaction mechanism explored by using density functional methods revealed that both kinetic and...

Copper(ii)-catalyzed boronic acid promoted chemoselective N-arylation of unprotected aminophenols has been developed. Selective N-arylation of 3-aminophenol is achieved with a Cu(OAc)2/AgOAc combination in MeOH at rt, whereas the chemoselective N-arylated products of 4-aminophenol can be obtained with a Cu(OAc)2/Cs2CO3 system and benzoic acid as an...

The present study reports the characterization of four degradation products from ezetemibe (EZB) through liquid chromatography-tandem mass spectrometry (LC-MS/MS) and the development of a validated and stability-indicating reversed-phase ultra-performance liquid chromatographic method for the determination of EZB in the presence of its process-rela...

A Cu (II)-catalyzed, inter/intramolecular C-N bond formation for the synthesis of various benzimidazole-fused heterocycles in a concise manner has been reported. The robustness of this reaction is demonstrated by the synthesis of a series of benzimidazole-fused heteroaromatics (e.g. pyrido[1,2-a] benzimidazole, benzimidazo[1,2-a]quinolines, benzimi...

Pyrano[2,3-c]carbazoles which are biologically valuable and synthetically challenging frameworks are synthesized in high yields over five steps from commercially available resorcinol. Palladium-catalyzed arylation remain a key step in this novel strategy. Versatility of this protocol has been demonstrated by the synthesis of naturally occuring alka...

Transamidation of a series of N,N-dimethyl amides with a wide range of primary and secondary amines is accomplished environmentally friendly using sulfuric acid adsorbed on silica gel as recyclable catalytic system.

A wide range of 4,6-diarylated/heterylated pyridin-2(1H)-one derivatives were synthesized in good to excellent yields from 1,3-diarylated/heterylated-2-propen-1-ones (chalcones) in one pot under metal and base-free conditions. This domino reaction suggests a novel mechanism comprising of Michael addition followed by amination, subsequent intramolec...

A copper (I)-catalyzed oxidative C-N bond cross-coupling reactions for the construction of imidazole-containing nitrogen bridgehead heterocycles have been developed under ligand and base free condition. This open-air reaction conditions is general and successfully applied in the synthesis of heterocycles such assubstituted imidazo[1,2-a]pyridines,...

A novel method of transamidation of carboxamides with amines by using catalytic amount of H2SO4-SiO2 has been developed under solvent free conditions. The transamidation is compatible with wide range of aromatic, heteroaromatic, aliphatic, cyclic/ acyclic primary or secondary amines. The metal/ solvent-free conditions represent a significant improv...

Cu (II)-Catalyzed cross-coupling of various aryl boronic acids with 5 and 6-amino indazoles has resulted the (arylamino)-indazoles. These resulted (arylamino)-indazoles have been utilized in synthesizing medicinally important pyrazole fused-carbazoles via Pd(II)-catalyzed cross-dehydrogenative coupling (CDC). This combined N-arylation/C-H arylation...

Copper (II)-catalyzed boronic acid promoted C-N bond cross-coupling reactions have been successfully developed for sequential N-arylation of C-amino-NH-azoles. These general protocols are compatible with a variety of aryl/hetero-aryl boronic acids and provided rapid access to diverse array of diarylaminoazole derivatives in two-steps sequence or in...

An iodine(III) catalyzed C(sp2)–H functionalization–intramolecular amination reaction of N-aryl-2-amino-N-heterocycles has been developed in water and under ambient conditions. This metal-free open-flask chemistry is general and successfully applied in synthesizing the benzimidazole-fused heterocycles pyrido[1,2-a]benzimidazole, benzimidazo[1,2-a]q...

Pd-catalyzed direct C-H arylation of N-methyl-7-azaindole at the C-2 position by diverse arylboronic acids was achieved at room temperature. The method is general and was applied in chemoselective synthesis of multiarylated 7-azaindole derivatives bearing three different aryl groups at the 2, 3, and 5 positions.

Copper promoted N-arylation of methyl 4-amino-3-iodobenzoate with boronic acids followed by Pd-catalyzed intramolecular C–H arylation provides an efficient route to methyl carbazole-3-carboxylate derivatives. This methodology was implemented in the synthesis of naturally occurring carbazole alkaloids clausine C, clausine H, clausine L, clausenalene...

A wide range of N-arylated 2-amino-N-heterocycles were synthesized by a copper-catalyzed boronic acid cross coupling reaction at ambient temperature in air. This ligand and base free methodology is general and could provide rapid access to a diverse array of potential bioactive heterocyclic compounds.

A three step path is developed to prepare the target compounds, including a cyclization to construct the chromene fragment [cf.

Here we demonstrate the synthesis of various derivatives of 5-(6-substituted phenyl-2H-chromen-3-yl)- oxazoles 5(a-k) by using Suzuki coupling conditions with different substituted boronic acids and obtained 23-57 % yields. We also synthesised various derivatives of the 5-(substituted 2H-chromen-3-yl)-oxazoles 3(a-j) mediated by TOSMIC as a reagent...

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.

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.

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.

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.

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.

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.

Copper-promoted N-arylation of quinazolin-4(3H)-ones with boronic acid at room temperature in the presence of air has been investigated. This method is general and can be applied to synthesizing derivatives of quinazolin-4(3H)-one with medicinal values.

Dithiocarbamate and DBU-promoted amide bond formation under microwave condition has been reported. The versatility of this synthetic protocol has been demonstrated with various carboxylic acids and different dithiocarbamates. The products thus obtained have been characterized by mp, IR, 1H NMR, and mass spectroscopy.

An efficient, general, and fully stereocontrolled synthesis of eremophilane-type compounds is disclosed. The approach features a highly diastereoselective Diels-Alder/aldol sequence to give a common intermediate, which is subsequently exploited to produce (+/-)-petasitolone and (+/-)-fukinone in a short sequence.

Permissions and Reprints Correction to Total Synthesis of (±)-Petasitolone and (±)-FukinoneSynthesis 2009; 2009(22): 3833-3837 DOI: 10.1055/s-0029-1218150 The advance online publication (e-First) version of this article contained an incorrect authors’ order and page number in reference 9. This mistake has been corrected for both the current onlin...

Synthesis of varenicline the antismoking drug has been achieved in six steps with 10% overall yield. A Diels–Alder reaction, oxidative cleavage of an olefin and reductive amination remain as key steps in the synthesis

The C11-C19 fragment of rhizoxin D was synthesized efficiently and stereoselectively. Stereoselective induction at C13 was achieved by means of the Crimmins protocol, whereas a substrate-controlled lithium aldol reaction gave the desired selectivity at the C17 position.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 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.

An efficient stereoselective synthesis of the C1-C10 and C11-O14 fragments of narbonolide, have been accomplished by using a thiazolidinonethione as chiral auxiliary. The stereocenters at C2, C3, C4, C5, C8, and C9 in C1-C10 fragment and C12 and 03 in C11-C14 fragment were generated via asymmetric acyl-thiazolidinethione aldol reactions whereas the...

A new and efficient route to the family of eremophilanes is reported. Key steps are the highly stereocontrolled Diels–Alder reaction and aldol condensation to furnish a cis-decalin system with the desired stereochemistry present in the eremophilane family of natural products. This approach is general and was utilized for the synthesis of (±)-eremop...

The synthesis of key precursor 5 of the macrolide core of rhizoxin D has been achieved by cross metathesis between two olefinic fragments 6 and 7. Both the olefinic fragments are easily synthesized in a diastereoselective manner from the common precursor 1-benzyloxy-2-methylhex-5-ene-3-ol (8).

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 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.

An efficient stereoselective synthesis of the C1–C10 fragment of narbonolide is reported. The stereocentres at C2, 3, 4, 5, 8 and 9 in fragment 5 can be generated via an iterative asymmetric acyl-thiazolidinethione aldol reaction, whereas the stereocentre at C6 is installed by means of Myers alkylation.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 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.

A rapid and efficient one-pot method for the synthesis of 2-(N-substituted)-aminobenzimidazoles is described. The reaction is promoted by dithiocarbamate and catalytic CuO. This procedure is general and can be applied to synthesize many potential drug candidates.

A concise and efficient synthesis of the macrolide core of migrastatin, an antimetastatic agent, is reported. In this synthetic protocol, the key intermediate (4R,5S,6S)-6-methoxy-5-(4-meth-oxybenzyloxy)-2,4-dimethylocta-2,7-dien-l-ol is obtained after diastereoselective aldol condensation, Lewis acid mediated diastereoselective addition, and an ex...