Synthesis of Pyrrolo[3,4-b]pyridin-5-ones via Ugi-Zhu Reaction and In Vitro-In Silico Studies against Breast Carcinoma

An Ugi-Zhu three-component reaction (UZ-3CR) coupled in a one-pot manner to a cascade process (N-acylation/aza Diels-Alder cycloaddition/decarboxylation/dehydration) was performed to synthesize a series of pyrrolo[3,4-b]pyridin-5-ones in 20% to 92% overall yields using ytterbium triflate as a catalyst, toluene as a solvent, and microwaves as a heat source. The synthesized molecules were evaluated in vitro against breast cancer cell lines MDA-MB-231 and MCF-7, finding that compound 1f, at a concentration of 6.25 μM, exhibited a potential cytotoxic effect. Then, to understand the interactions between synthesized compounds and the main proteins related to the cancer cell lines, docking studies were performed on the serine/threonine kinase 1 (AKT1) and Orexetine type 2 receptor (Ox2R), finding moderate to strong binding energies, which matched accurately with the in vitro results. Additionally, molecular dynamics were performed between proteins related to the studied cell lines and the three best ligands.

Anti-tumor compounds identification from gossypol Groebke imidazopyridine product

Series of imidazo[1,2-a]pyridines designed from gossypol modification based on Groebke-Blackburn-Bienaymé reaction were discovered as potent Bcl-2 inhibitors. Compound 4 was found to display good anti-proliferative activities for 7 human cancer cell lines (0.33-1.7 µM) among them, which were better than separate gossypol and imidazopyridine moiety compounds. It was capable of suppressing antiapoptotic proteins Bcl-2 and Bcl-X_L demonstrated by mechanism studies, and possible binding model was also illustrated by molecular modelling.

How and Why to Investigate Multicomponent Reactions Mechanisms? A Critical Review

We review the most innovative efforts and greatest challenges faced when elucidating multicomponent reactions (MCRs) mechanisms. When compared to traditional reactions, the often two or more concurrent reactions pathways and the greater number of possible intermediates in MCRs turn their mechanistic investigation both a harder and trickier task. The common approaches used to investigate reaction mechanisms are often unable to clarify MCRs mechanisms; hence few but clever approaches are currently used to determine these mechanisms and to depict their key transformations. Their complexity has required most innovative approaches and the use of a number of unique techniques that have shed light over the favored pathway selected from the myriad of alternatives theoretically available for MCRs. This review focuses on the most successful efforts applied by a few leading groups to perform these puzzlingly investigations.

Activated Carbon/MoO3: Efficient Catalyst for Green Synthesis of Chromeno[d]pyrimidinediones and Xanthenones

BACKGROUND

Nanoscale metal oxide catalysts have been extensively employed in organic reactions because they have been found to influence the chemical and physical properties of bulk material. The chromene (benzopyran) nucleus constitutes the core structure in a major class of many biologically active compounds, and interest in their chemistry consequently continues because of their numerous biological activities. The xanthene (dibenzopyran) derivatives are classified as highly significant compounds which display a number of various bioactive properties. Pyrimidinones have also gained interest due to their remarkable biological utilization, such as antiviral, antibacterial, antihypertensive, antitumor, and calcium blockers effects.

OBJECTIVE

The aim of this work presented herein was to prepare activated carbon/MoO3 nanocomposite and explore its role as a green and recyclable catalyst for the synthesis of chromeno[d]pyrimidinediones and xanthenones under ethanol-drop grinding at room temperature.

METHODS

The activated carbon/MoO3 nanocomposite was prepared successfully via a simple route in which the carbonization of gums as new natural precursors was used for the synthesis of activated carbon. This nanocomposite was then effectively used in a reaction of 3,4-methylenedioxyphenol, aromatic aldehydes, and active methylene compounds, including 1,3-dimethylbarbituric acid and dimedone, to synthesize a series of chromeno[d]pyrimidinediones and xanthenones in high yields. The synthesized catalyst was characterized by Fourier transform infrared spectroscopy (FT-IR), Powder x-ray diffractometry (XRD), Scanning electron microscope (SEM), Raman spectroscopy, and also by TGA analysis. Confirmation of the structures of compounds 5(a-g) and 6(a-g) were also established with IR, 1H NMR, and 13C NMR spectroscopic data and also by elemental analyses.

RESULTS

A number of 6,8-dimethyl-10-phenyl-6,10-dihydro-7H-[1,3]dioxolo[4´,5´:6,7]chromeno[2,3- d]pyrimidine-7,9(8H)-diones and 7,7-dimethyl-10-(4-methylphenyl)-6,7,8,10-tetrahydro-9H-[1,3]dioxolo[ 4,5-b]xanthen-9-ones were effectively synthesized using activated carbon/MoO3 nanocomposite (0.05 gr) as a catalyst under ethanol-drop grinding at room temperature. The desired products were obtained in high yields (93-97%) within short reaction times (15-20 min).

CONCLUSION

This paper investigates the catalytic potential of the synthesized activated carbon/MoO3 nanocomposite for the preparation of chromeno[d]pyrimidinediones and xanthenones under the ethanol-drop grinding procedure. The mildness of the reaction conditions, high yields of products, short reaction times, experimental simplicity, and avoiding the use of harmful solvents or reagents makes this procedure preferable for the synthesis of these compounds.

One-pot synthesis of substituted pyrrole-imidazole derivatives with anticancer activity

A facile and efficient method to synthesize pyrrole-imidazole was developed via a post-Ugi cascade reaction followed by one purification procedure. Synthesized pyrrole-imidazole was collected by performing a mild reaction and a simple procedure, which could be applicable to a broad scope of functionalized anilines. The screening results demonstrated that compound 7e exhibited a high potency of anticancer activity in human pancreatic cancer cell lines PANC and ASPC-1. Our work shed light on the potential of post-Ugi cascade reaction in combinatorial and medicinal chemistry.

Synthesis of N-heterocycles containing 1,5-disubstituted-1H-tetrazole via post-Ugi-azide reaction

Ugi-azide four-component reaction (UA-4CR) as development on Ugi four-component reaction (U-4CR) is the condensation reaction involving an aldehyde, an amine, an isocyanide, and an azide source. Nowadays, UA-4CR has been employed for the efficient and facile production of 1,5-disubstituted-1H-tetrazoles (1,5-DS-1H-Ts). Interestingly, the combination of 1,5-DS-1H-Ts with suitable post-transformations in a tandem manner results in the construction of various classes of heterocyclic compounds bearing 1,5-DS-1H-T moiety. This review aims to provide the application of diverse post-Ugi-azide reaction in the preparation of different N-heterocyclic compounds bearing 1,5-DS-1H-T such as substituted and fused 1,5-DS-1H-Ts.

Chemistry and Pharmacological Activities of Biginelli Product- A Brief Overview

Dihydropyrimidinones are extremely advantageous small sized molecules owning adaptable pharmaceutical properties. With a molecular formula C₄H₆N₂O, they hold a wide range of biological activities. It is a heterocyclic moiety having two N-atoms at positions 1 and 3. They are derivatives of pyrimidine containing an additional ketone group. They have inspired development of a wide range of synthetic methods for preparation and chemical transformations. Taking into consideration their structural similarity and involvement with DNA and RNA, they have become very imperative in the world of synthetic organic chemistry. Aryl substituted moieties and their derivatives are significant class of substances in medicinal and organic chemistry. Many alkaloids from natural marine sources comprising dihydropyrimidinones core have been isolated which possess fascinating biological properties. Intensive explorations have been carried out on these compounds because they possess close similitude to clinically used nifedipine, nicardipine etc. which are also Biginelli product analogues. Due to the interesting pharmacological properties associated with the privileged DHPM structures, the Biginelli reaction and related procedures have received increasing attention in recent years.

Microwave-assisted facile construction of quinoxalinone and benzimidazopyrazinone derivatives via two paths of post-Ugi cascade reaction

A facile and efficient route to synthesize quinoxalinone and benzimidazopyrazinone was developed via two paths of a post-Ugi cascade reaction. By simply alternating the order of nucleophilic substitution reactions, both heterocycles could be accessed selectively from the same Ugi adduct. Microwave-assisted synthesis protocol provided these compounds with one purification procedure for three steps. These two scaffolds with more possible spaces for further modifications provide great benefit toward combinatorial and medicinal chemistry campaigns.

A facile solvent-free three-component domino synthesis of novel 2,4-diaryl-5,6-dihydrobenzo[j][1,7]phenanthrolines

A simple, efficient and green procedure for the synthesis of novel 2,4-diaryl-5,6-dihydrobenzo[j][1,7]phenanthrolines has been developed via a Krohnke-type one-pot three-component reaction of 2-[arylmethylidene]-3,4-dihydro-1(2H)-acridinones and (2-aryl-2-oxoethyl)pyridinium bromides in the presence of excess ammonium acetate in good yields under solvent-free conditions. Good functional group tolerance, high substrate scope and no column purification are the practical advantages of this methodology.

Regioselective four-component synthesis of new tetrazolo[1,5-a]quinoline-based 2-amino-1,4-dihydropyridine and pyridin-2(1H)-one derivatives using nano-ZnO catalysis

Four-component reaction between primary amines, dialkylacetylendicarboxylates, tetrazolo[1,5-a] quinoline-4-carbaldehyde and ethyl-2-cyanoacetate in the presence of 1,4-diaza-bicyclo[2.2.2]octane and zinc oxide nanoparticles results to the regioselective production of new tetrazolo[1,5-a]quinoline-based 2-amino-1,4-dihydropyridine or pyridin-2(1H)-one derivatives in good to high yields. The selectivity of the catalyzed reaction toward the generation of the dihydropyridine or pyridin-2(1H)-one derivatives was found to be strongly dependent on the size of the alkyl groups in the ester moieties of the acetylenic esters. According to single-crystal X-ray diffraction and NMR studies, the pyridin-2(1H)-one derivatives involve a restricted rotation around the C-C bond connecting the tetrazoloquinoline and dihydropyridinone cyclic systems.

High diastereoselective amine-catalyzed Knoevenagel-Michael-cyclization-ring-opening cascade between aldehydes, 3-arylisoxazol-5(4H)-ones and 3-aminocyclohex-2-en-1-ones

A highly diastereoselective three-component cascade reaction among aromatic aldehydes, 3-arylisoxazol-5(4H)-ones and 3-aminocyclohex-2-en-1-ones takes place under the catalysis of triethylamine, providing (3SR,4SR)-4-aryl-3-[(E)-(hydroxyimino)(aryl)methyl]-4,6,7,8-tetrahydroquinoline-2,5(1H,3H)-diones in 45-85% yields. The transformation presumably proceeds through a sequential cascade of Knoevenagel/Michael-addition/cyclization/ring-opening reactions. This process was carried out in green media (EtOH/water, 1:1-1:3) at reflux. Products are crystallized directly from the reaction mixture and their isolation includes only filtration. The structure of (3SR,4SR)-3-[(E)-(hydroxyimino)(phenyl)methyl]-7,7-dimethyl-4-phenyl-4,6,7,8-tetrahydroquinoline-2,5(1H,3H)-dione was confirmed by X-ray diffraction analysis.

Recent developments in the synthesis and applications of dihydropyrimidin-2(1H)-ones and thiones

Dihydropyrimidin-2(1H)-ones/thiones (DHPMs) are important heterocyclic compounds owing to their excellent biological activities and have been widely utilized in pharmaceutical applications. Recently, numerous DHPM derivatives have been prepared. This review covers the synthesis of DHPMs and improved procedures for the preparation of DHPMs from 1995 to 2016.

Synthesis of functionalized dihydro-2-oxopyrroles using graphene oxide as heterogeneous catalyst

A mild, efficient synthetic approach for the synthesis of highly functionalized dihydro-2-oxopyrroles is developed by using graphene oxide, a readily available and inexpensive material, as an eco-benign solid acid catalyst in ethanol at room temperature. The present methodology displays several advantages such as practical simplicity, high atom economy, easy workup procedure, and high yields of the products.

One-pot synthesis of novel 1-(1H-tetrazol-5-yl)-1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazine derivatives via an Ugi-azide 4CR process

A facile one-pot method has been developed for the synthesis of novel pyrrolo[2,1-a]pyrazine scaffolds. A variety of 1-(1H-tetrazol-5-yl)-1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazine derivatives were obtained in moderate to high yields in methanol using a one-pot four-component condensation of 1-(2-bromoethyl)-1H-pyrrole-2-carbaldehyde, amine, isocyanide and sodium azide at room temperature. These reactions presumably proceed via a domino imine formation, intramolecular annulation and Ugi-azide reaction. Unambiguous assignment of the molecular structures was carried out by single-crystal X-ray diffraction.

New route for the synthesis of new cyanoimino- and cyanoaminopyrimidines

A novel series of 4-aryl-2-cyanoimino-3,4-dihydro-1H-pyrimidines (aryl-CIDHPMs) was synthesized using a new method via the one-pot three-component reaction of cyanoguanidine with malononitrile and aromatic aldehydes using sodium methoxide as catalyst. These new aryl-CIDHPMs were also prepared by a classical route via reaction of cyanoguanidine with the corresponding arylidenemalononitriles under our conditions. In the same manner, the reaction of cyanoguanidine with cyclohexylidenemalononitrile and/or isatinylidenemalononitrile afforded new spiro-pyrimidines 9 and 10, respectively. A new series of polyfunctionalized 2-cyanoaminopyrimidines was obtained from the reaction of cyanoguanidine with cinnamaldehyde and/or ethoxyalkylenemalononitriles.

Effective DABCO-catalyzed synthesis of new tetrazolo[1,5-a]pyrimidine analogs

In this study, an efficient multicomponent one-pot route is described for the DABCO-catalyzed synthesis of tetrazolo[1,5-a]pyrimidines. This synthesis strategy is based on the reaction of malononitrile and aldehydes with 5-aminotetrazole monohydrate using 1,4-diazabicyclo[2.2.2]octane (DABCO) in i-PrOH under reflux conditions. This protocol is a simple, green, and low-cost technique to prepare new compounds with potential medicinal properties.

Ultrasound Assisted Synthesis of Quinoline Derivatives in the Presence of SnCl2·2H2O as a Precatalyst in Water: Evaluation of their Antibacterial Activities

BACKGROUND

SnCl2·2H2O has been used as a convenient precatalyst for the one-pot and rapid synthesis of 2-substituted quinolines under ultrasound irradiation in water. The reaction involved a 3-component reaction of aniline, aldehydes, and ethyl 3,3-diethoxypropionate in the presence of aerial oxygen to give the desired products in good yields.

CONCLUSION

Several of these compounds showed antibacterial activities when tested against gram-positive and gram-negative species. One compound i.e. 4b showed promising activities across both the species.

Urea/thiourea: efficient, inexpensive and reusable catalysts for the synthesis of pyrazole derivatives with 2-iminothiazolidin-4-one and 2,4-thiazolidinediones under solvent-free conditions

An efficient and green synthesis of pyrazolyl-2,4-thiazolidinediones/pyrazolyl-2-iminothiazolidine-4-ones 7(a-j) has been developed using urea/thiourea as catalyst. Two methods (A and B) have been introduced for the synthesis of these compounds. Method A performed well for the condensation of pyrazole-4-carboxaldehydes 4(a-e) with 2-iminothiazolidin-4-one 5a and with 2,4-thiazolidinedione 5b at 110 [Formula: see text] for 16-20 min to furnish (Z)-5-((1,3-diphenyl-1H-pyrazol-4-yl)methylene)thiazolidine-2,4-diones 7(a-j) in excellent yields. In method B, the pyrazole-4-carboxaldehydes 4(a-e) were condensed with urea/thiourea at 110 [Formula: see text] for 10 min to give key intermediates 6(a-j) which were later condensed with 5a and 5b to afford 7(a-j) via the elimination of urea/thiourea rather than the formation of a Biginelli product. These two protocols are inexpensive, eco-friendly and high yielding to provide the final products. The synthesis of compound 7f.

Synthesis of amino ester-embedded benzimidazoles: a one-pot sequential protocol under metal-free neutral conditions

A one-pot three-component protocol has been developed for the synthesis of amino ester-embedded benzimidazoles under metal-free neutral conditions. Sequentially, the methodology involves coupling of an amino ester with 1-fluoro-2-nitrobenzene, reduction of the coupled nitroarene by sodium dithionite, and cyclization of the corresponding diamine with an aldehyde.

Ethylene glycol promoted catalyst-free pseudo three-component green synthesis of bis(coumarin)s and bis(3-methyl-1-phenyl-1H-pyrazol-5-ol)s

An ethylene glycol promoted catalyst-free practically efficient and sustainable approach has been developed for the synthesis of several benzylidene-bis-(4-hydroxycoumarin)s and 4,[Formula: see text]-(arylmethylene)-bis(3-methyl-1-phenyl-1H-pyrazol-5-ol)s by the pseudo three-component reaction of an aldehyde with 4-hydroxycoumarin and 3-methyl-1-phenylpyrazol-5-one, respectively. Inexpensive, non-toxic, and easily available ethylene glycol used as the reaction solvent and promoter renders an efficient protocol in terms of catalyst-free reaction conditions, short reaction time, high yield, practical utility, and green approach.

Cerium oxide-catalyzed multicomponent condensation approach to spirooxindoles in water

An efficient and facile green synthesis of spirooxindole derivatives bearing pyrano[2,3-c]pyrazole moiety has been achieved via a [Formula: see text]-NPs catalyzed four-component reaction in water. The protocol offers an environmentally benign and effective approach to highly functionalized and biologically interesting spiro[indoline-3,4[Formula: see text]-pyrano[2,3-c]pyrazole] derivatives. The synthesized compounds exhibit potent antioxidant and antibacterial activities.

Novel domino procedures for the synthesis of chromene derivatives and their isomerization

Novel tricyclic keto diesters have been synthesized by a one-pot three-component procedure via DABCO-catalyzed domino Knoevenagel-Michael addition reactions. Also, an efficient four-component reaction for the synthesis of another new group of tricyclic keto diesters has been developed via domino Knoevenagel-intramolecular oxo-Diels-Alder reactions. A selective thermal isomerization of the synthesized chromenes to fumarates is also described. X-ray analyses confirm unambiguously the structures of the products.

Catalyst-free multicomponent synthesis of novel adamantyl-containing tetrahydropyrimidine carboxylates

[Formula: see text]-Enaminoesters were generated in situ by the reaction of aliphatic or aromatic primary amines to electron-deficient alkynes, dimethyl acetylenedicarboxylate, and methyl propiolate. [Formula: see text]-Enaminoesters thus formed were reacted with 1-adamantanamine and formaldehyde in methanol to give novel molecular hybrids: dimethyl 3-((3s,5s,7s)-adamantan-1-yl)-1-(alkyl/aralkyl/aryl)-1,2,3,4-tetrahydropyrimidine-5,6-dicarboxylates (5a-j) and methyl 3-((3s,5s,7s)-adamantan-1-yl)-1-(alkyl/aralkyl/aryl)-1,2,3,4-tetrahydropyrimidine-5-carboxylates (9a-j). The structures of the molecular hybrids have been established based on the spectral and analytical data. Structural confirmation of the products was done by X-ray crystallography of 5d as a representative product of the series.

One-pot four-component synthesis of highly substituted [1,2,4]triazolo[1,5-a]pyrimidines

A green one-pot four-component strategy has been developed for the synthesis of [1,2,4]triazolo[1,5-a]pyrimidine-6-carboxamide derivatives using an amine, 2,2,6-trimethyl-4H-1,3-dioxin-4-one, an aldehyde, and 3-amino-1,2,4-triazole in the presence of a catalytic amount of p-toluenesulfonic acid in water within 4-6 h.

Cloning, distribution and effects of fasting status of melanocortin 4 receptor (MC4R) in Schizothorax prenanti

Melanocortin 4 receptor (MC4R) has an important role in the regulation of energy homeostasis in both mammals and fish. In this study, MC4R was characterized in S. prenanti (Schizothorax prenanti) and designated as SpMC4R. SpMC4R cDNA is composed of 1004 nucleotides with a 978 nucleotide open reading frame encoding a protein of 326 amino acids. The SpMC4R contained predicted regions that were structural features of MCR subtypes of vertebrates. In addition, phylogenetic analyses suggested that S. prenanti MC4R was closely related to fish MC4Rs. The SpMC4R mRNA was detected in embryos at developmental stages. Further, its mRNA was detectable in unfertilized eggs. Using real-time RT-PCR, MC4R is widely expressed, with highest levels of expression in brain and ovary. An experiment was conducted to determine the expression profile of MC4R during short-term and long-term fasting of the brain. The expression level of MC4R in unfed fish was significantly increased at 6, 9 and 24h post-fasting (hpf) and 14days fasting than in fed fish, this suggests that MC4R is conserved peptide that might be involved in the regulation of food intake and other physiological function in S. prenanti.

Characterization, tissue distribution and regulation of agouti-related protein (AgRP) in a cyprinid fish (Schizothorax prenanti)

Agouti-related protein (AgRP) is an important neuropeptide involved in the regulation of feeding in both mammals and fish. In this study, we have cloned the full-length cDNA sequence for AgRP in a cyprinid fish (Schizothorax prenanti). The AgRP gene, encoding 126-amino acids, was strongly expressed in the brain. The AgRP gene was detected in embryos at developmental stages. Further, its mRNA was detectable in unfertilized eggs. An experiment was conducted to determine the expression profile of AgRP during short-term and long-term fasting of the hypothalamus. The expression level of AgRP in unfed fish was significantly increased at 3 and 4h post-fasting than in fed fish but did not affect AgRP mRNA expression after 14 days fasting. Overall, our results suggest that AgRP is a conserved peptide that might be involved in the regulation of short-term feeding and other physiological function in Schizothorax prenanti.