4-(5-Amino-pyrazol-1-yl)benzenesulfonamide derivatives as novel multi-target anti-inflammatory agents endowed with inhibitory activity against COX-2, 5-LOX and carbonic anhydrase: Design, synthesis, and biological assessments

Discovery of new anti-diabetic potential agents based on paracetamol incorporating sulfa-drugs: Design, synthesis, α-amylase, and α-glucosidase inhibitors with molecular docking simulation

Uncontrolled diabetes can lead to hyperglycemia, which causes neuropathy, heart attacks, retinopathy, and nervous system damage over time, therefore, controlling hyperglycemia using potential drug target inhibitors is a promising strategy. This work focused on synthesizing new derivatives via the diazo group, using a hybridization strategy involving two approved drugs, paracetamol and several sulfonamides. The newly designed diazo-paracetamols 5-12 were fully characterized and then screened for in vitro α-amylase and α-glucosidase activities and exhibited inhibitory percentages (IP) = 92.5-96.5 % and 91.0-95.7 % compared to Acarbose IP = 96.5 and 95.8 %, respectively at 100 μg/mL. The IC50 values of the synthesized derivatives were evaluated against α-amylase and α-glucosidase enzymes, and the results demonstrated moderate to potent activity. Among the tested diazo-paracetamols, compound 11 was found to have the highest potency activity against α-amylase with IC50 value of 0.98 ± 0.015 μM compared to Acarbose IC50 = 0.43 ± 0.009 μM, followed by compound 10 (IC50 = 1.55 ± 0.022 μM) and compound 9 (IC50 = 1.59 ± 0.023 μM). On the other hand, for α-glucosidase, compound 10 with pyrimidine moiety demonstrated the highest inhibitory activity with IC50 = 1.39 ± 0.021 μM relative to Acarbose IC50 = 1.24 ± 0.029 μM and the order of the most active derivatives was 10 > 9 (IC50 = 2.95 ± 0.046 μM) > 11 (IC50 = 5.13 ± 0.082 μM). SAR analysis confirmed that the presence of 4,5-dimethyl-isoxazole or pyrimidine nucleus attached to the sulfonyl group is important for activity. Finally, the docking simulation was achieved to determine the mode of binding interactions for the most active derivatives in the enzyme's active site.

Design, synthesis and anti-inflammatory assessment of certain substituted 1,2,4-triazoles bearing tetrahydroisoquinoline scaffold as COX 1/2-inhibitors

Aiming to discover effective and safe non-steroidal anti-inflammatory agents, a new set of 1,2,4-triazole tetrahydroisoquinoline hybrids 9a-g, 11a-g and 12a-g was synthesized and evaluated as inhibitors of COX-1 and COX-2. In order to overcome the adverse effects of highly selective COX-2 and non-selective COX-2 inhibitors, the compounds of this study were designed with the goal of obtaining moderately selective COX-2 inhibitors. In this study compounds 9e, 9g and 11f are the most effective derivatives against COX-2 with IC50 values 0.87, 1.27 and 0.58 µM, respectively which are better than or comparable to the standard drug celecoxib (IC50 = 0.82 µM) but with lower selectivity indices as required by our goal design. The results of the in vivo anti-inflammatory inhibition test revealed that compounds 9e, 9g and 11f displayed a higher significant anti-inflammatory activity than celecoxib at all-time intervals. In addition, these compounds significantly decreased the production of inflammatory mediators PGE-2, TNF-ɑ and IL-6. Compounds 9e, 9g and 11f had a safe gastric profile compared to indomethacin, also compound 11f (ulcerogenic index = 1.33) was less ulcerous than the safe celecoxib (ulcerogenic index = 3). Moreover, histopathological investigations revealed a normal architecture of both paw skin and gastric mucosa after oral treatment of rats with compound 11f. Furthermore, molecular docking studies were performed on COX-1 and COX-2 to study the binding pattern of compounds 9e, 9g and 11f on both isoenzymes.

Synthesis, COX-2 inhibition, anti-inflammatory activity, molecular docking, and histopathological studies of new pyridazine derivatives

Five new pyridazine scaffolds were synthesized and assessed for their inhibitory potential against both cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) compared with indomethacin and celecoxib. The majority of the synthesized compounds demonstrated a definite preference for COX-2 over COX-1 inhibition. Compounds 4c and 6b exhibited enhanced potency towards COX-2 enzyme with IC50 values of 0.26 and 0.18 µM, respectively, compared to celecoxib with IC50 = 0.35 µM. The selectivity index (SI) of compound 6b was 6.33, more than that of indomethacin (SI = 0.50), indicating the most predominant COX-2 inhibitory activity. Consequently, the in vivo anti-inflammatory activity of compound 6b was comparable to that of indomethacin and celecoxib and no ulcerative effect was detected upon the oral administration of compound 6b, as indicated by the histopathological examination. Moreover, compound 6b decreased serum plasma PEG2 and IL-1β. To rationalize the selectivity and potency of COX-2 inhibition, a molecular docking study of compound 6b into the COX-2 active site was carried out. The COX-2 inhibition and selectivity of compound 6b can be attributed to its ability to enter the side pocket of the COX-2 enzyme and interact with the essential amino acid His90. Together, these findings suggested that compound 6b is a promising lead for the possible design of COX-2 inhibitors that could be employed as safe and effective anti-inflammatory drugs.

Pyrazole derivatives ameliorate synovial inflammation in collagen-induced arthritis mice model via targeting p38 MAPK and COX-2

The type II collagen-induced arthritis (CIA) model and human rheumatoid arthritis exhibit similar characteristics. Both diseases involve the production of inflammatory cytokines and other mediators, triggering an inflammatory cascade linked to bone and cartilage damage. Recently, new pyrazole compounds with various pharmacological activities, including antimicrobial, anticancer, anti-inflammatory, and analgesic agents, have been reported. Our aim is to evaluate the therapeutic effectiveness of two newly synthesized pyrazole derivatives, M1E and M1G, in reducing inflammation and oxidative stress in a mouse model of collagen-induced arthritis. Arthritis was induced in DBA/1J mice, and the therapeutic effect of the M1E and M1G is assessed by measuring the arthritic index, quantifying the expression of inflammatory genes such as p38 MAPK, COX-2, IL1β, MMP3, and TNF-α using real-time PCR and analyzing protein expression using western blotting for phosphorylated p38 MAPK and COX-2. Oxidative stress markers and hind paws joint histopathology were also evaluated. Treatment with the two pyrazole derivatives significantly (p < 0.001) improved the arthritic score; downregulated the expression of inflammatory genes p38 MAPK, COX-2, IL1β, MMP3, and TNF-α; and reduced the protein expression of phosphorylated p3  MAPK and COX-2. In addition, both compounds ameliorated oxidative stress by increasing the activities of SOD and reducing the formation of MDA in the paw tissue homogenates. Both M1E and M1G significantly (p < 0.001) improved the pathological features of synovitis. The pyrazole derivatives, M1E and M1G, significantly reduced the arthritic score and the inflammatory cytokine expression, improved synovitis histopathology, and ameliorated oxidative stress in the CIA mice model.

Chemistry of heterocycles as carbonic anhydrase inhibitors: A pathway to novel research in medicinal chemistry review

Nowadays, the scientific community has focused on dealing with different kinds of diseases by exploring the chemistry of various heterocycles as novel drugs. In this connection, medicinal chemists identified carbonic anhydrases (CA) as one of the biologically active targets for curing various diseases. The widespread distribution of these enzymes and the high degree of homology shared by the different isoforms offer substantial challenges to discovering potential drugs. Medicinal and synthetic organic chemists have been continuously involved in developing CA inhibitors. This review explored the chemistry of different heterocycles as CA inhibitors using the last 11 years of published research work. It provides a pathway for young researchers to further explore the chemistry of a variety of synthetic as well as natural heterocycles as CA inhibitors.

Evaluation of antibacterial, cytotoxicity, and apoptosis activity of novel chromene-sulfonamide hybrids synthesized under solvent-free conditions and 3D-QSAR modeling studies

In this study, eleven novel chromene sulfonamide hybrids were synthesized by a convenient method in accordance with green chemistry. At first, chromene derivatives (1-9a) were prepared through the multi-component reaction between aryl aldehydes, malononitrile, and 3-aminophenol. Then, synthesized chromenes were reacted with appropriate sulfonyl chlorides by grinding method to give the corresponding chromene sulfonamide hybrids (1-11b). Synthesized hybrids were obtained in good to high yield and characterized by IR, 1HNMR, 13CNMR, CHN and melting point techniques. In addition, the broth microdilution assay was used to determine the minimal inhibitory concentration of newly synthesized chromene-sulfonamide hybrids. The MTT test was used to determine the cytotoxicity and apoptotic activity of the newly synthesized compounds against fibroblast L929 cells. The 3D‑QSAR analysis confirmed the experimental assays, demonstrating that our predictive model is useful for developing new antibacterial inhibitors. Consequently, molecular docking studies were performed to validate the findings of the 3D-QSAR analysis, confirming the potential binding interactions of the synthesized chromene-sulfonamide hybrids with the target enzymes. Molecular docking studies were employed to support the 3D-QSAR predictions, providing insights into the binding interactions between the newly synthesized chromene-sulfonamide hybrids and their target bacterial enzymes, thereby reinforcing the potential efficacy of these compounds as antibacterial agents. Also, some of the experimental outcomes supported or conflicted with the pharmacokinetic prediction (especially about compound carcinogenicity). The performance of ADMET predictor results was assessed. The work presented here proposes a computationally driven strategy for designing and discovering a new sulfonamide scaffold for bacterial inhibition.

Explore new quinoxaline pharmacophore tethered sulfonamide fragments as in vitro α-glucosidase, α-amylase, and acetylcholinesterase inhibitors with ADMET and molecular modeling simulation

A new series of quinoxaline-sulfonamide derivatives 3-12 were synthesized using fragment-based drug design by reaction of quinoxaline sulfonyl chloride (QSC) with different amines and hydrazines. The quinoxaline-sulfonamide derivatives were evaluated for antidiabetic and anti-Alzheimer's potential against α-glucosidase, α-amylase, and acetylcholinesterase enzymes. These derivatives showed good to moderate potency against α-amylase and α-glucosidase with inhibitory percentages between 24.34 ± 0.01%-63.09 ± 0.02% and 28.95 ± 0.04%-75.36 ± 0.01%, respectively. Surprisingly, bis-sulfonamide quinoxaline derivative 4 revealed the most potent activity with inhibitory percentages of 75.36 ± 0.01% and 63.09 ± 0.02% against α-glucosidase and α-amylase compared to acarbose (IP = 57.79 ± 0.01% and 67.33 ± 0.01%), respectively. Moreover, the quinoxaline derivative 3 exhibited potency as α-glucosidase and α-amylase inhibitory with a minute decline from compound 4 and acarbose with inhibitory percentages of 44.93 ± 0.01% and 38.95 ± 0.01%. Additionally, in vitro acetylcholinesterase inhibitory activity for designed derivatives exhibited weak to moderate activity. Still, sulfonamide-quinoxaline derivative 3 emerged as the most active member with inhibitory percentage of 41.92 ± 0.02% compared with donepezil (IP = 67.27 ± 0.60%). The DFT calculations, docking simulation, target prediction, and ADMET analysis were performed and discussed in detail.

Novel N-pyrocatechoyl and N-pyrogalloyl hydrazone antioxidants endowed with cytotoxic and antibacterial activity

Over the years, pharmacological agents bearing antioxidant merits arose as beneficial in the prophylaxis and treatment of various health conditions. Hazardous effects of radical species hyperproduction disrupt normal cell functioning, thus increasing the possibility for the development of various oxidative stress-associated disorders, such as cancer. Contributing to the efforts for efficient antioxidant drug discovery, a thorough in vitro and in silico assessment of antioxidant properties of 14 newly synthesized N-pyrocatechoyl and N-pyrogalloyl hydrazones (N-PYRs) was accomplished. All compounds exhibited excellent antioxidant potency against the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. The extensive in silico analysis revealed multiple favorable features of N-PYRs to inactivate harmful radical species, which supported the obtained in vitro results. Also, in silico experiments provided insights into the preferable antioxidant pathways. Prompted by these findings, the cytotoxicity effects and the influence on the redox status of cancer HCT-116 cells and healthy fibroblasts MRC-5 were evaluated. These investigations exposed four analogs exhibiting both cytotoxicity and selectivity toward cancer cells. Furthermore, the frequently uncovered antimicrobial potency of hydrazone-type hybrids encouraged investigations on G+ and G- bacterial strains, which revealed the antibacterial potency of several N-PYRs. These findings highlighted the N-PYRs as excellent antioxidant agents endowed with cytotoxic and antibacterial features.

Synthetic Approaches to Novel Human Carbonic Anhydrase Isoform Inhibitors Based on Pyrrol-2-one Moiety

New dihydro-pyrrol-2-one compounds, featuring dual sulfonamide groups, were synthesized through a one-pot, three-component approach utilizing trifluoroacetic acid as a catalyst. Computational analysis using density functional theory (DFT) and condensed Fukui function explored the structure-reactivity relationship. Evaluation against human carbonic anhydrase isoforms (hCA I, II, IX, XII) revealed potent inhibition. The widely expressed cytosolic hCA I was inhibited across a range of concentrations (KI 3.9-870.9 nM). hCA II, also cytosolic, exhibited good inhibition as well. Notably, all compounds effectively inhibited tumor-associated hCA IX (KI 1.9-211.2 nM) and hCA XII (low nanomolar). Biological assessments on MCF7 cancer cells highlighted the compounds' ability, in conjunction with doxorubicin, to significantly impact tumor cell viability. These findings underscore the potential therapeutic relevance of the synthesized compounds in cancer treatment.

Development of safe and antioxidant COX-2 inhibitors; Synthesis, molecular docking analysis and biological evaluation of novel pyrrolizine 5-carboxamides

In the current study, a series of new pyrrolizine-5-carboxamide derivatives (5-8, 9a-d, 10a-d, 11a,b and 12a,b) were developed, synthesized and evaluated in terms of in vitro COX-2 enzyme inhibition. The in vivo anti-inflammatory evaluation was conducted on the most selective compounds (9a,b,d, 10b,c and 11a,b). For the most active five compounds (9a, 10b,c and 11a,b), ulcerogenic liability, histopathological examinations, physicochemical properties study and antioxidant activity were investigated. Also, nitric oxide donor activity was evaluated for compounds (6, 7, 10a-d and 12a,b), while, compounds (10c,d and 12a,b) showed a high significant result relative to the normal control. According to the findings of this study, 2,3-dihydro-1H-pyrrolizine-5-carboxamide (9a) demonstrated high antioxidant (highest beta-carotene concentration (10.825 µg/ml)) and anti-inflammatory activity (EIP = 63.6 %) with lower ulcerogenicity (ulcer index 13.67), presenting it as a promising candidate for treating inflammatory diseases which are complicated by oxidative tissue damage. Furthermore, MOE software tools docking software was used to carry out the in silico studies. Docking study for the most active compounds showed that all compounds made three to four H-bond interactions in COX-2 active site adopting excellent docking scores.

Rational design and eco-friendly one-pot multicomponent synthesis of novel ethylidenehydrazineylthiazol-4(5H)-ones as potential apoptotic inducers targeting wild and mutant EGFR-TK in triple negative breast cancer

A novel series of ethylidenehydrazineylthiazol-4(5H)-ones were synthesized using various eco-friendly one-pot multicomponent synthetic techniques. The anticancer activity of compounds (4a-m) was tested against 11 cancer cell lines. While the IC50 of all compounds was evaluated against the most sensitive cell lines (MDA-MB-468 and FaDu). Our SAR study pinpointed that compound 4a, having a phenyl substituent, exhibited a significant growth inhibition % against all cancer cell lines. The frontier anticancer candidates against the MDA-MB-468 were also examined against the wild EGFR (EGFR-WT) and mutant EGFR (EGFR-T790M) receptors. Most of the synthesized compounds exhibited a higher inhibitory potential against EGFR-T790M than the wild type of EGFR. Remarkably, compound 4k exhibited the highest inhibitory activity against both EGFR-WT and EGFR-T790M with IC50 values (0.051 and 0.021 µM), respectively. The pro-apoptotic protein markers (p53, BAX, caspase 3, caspase 6, caspase 8, and caspase 9) and the anti-apoptotic key marker (BCL-2) were also measured to propose a mechanism of action for the compound 4k as an apoptotic inducer for MDA-MB-468. Investigation of the cell cycle arrest potential of compound 4k was also conducted on MDA-MB-468 cancer cells. We also evaluated the inhibitory activities of compounds (4a-m) against both EGFR-WT and EGFR-T790M using two different molecular docking processes.

Dual-target inhibitors based on COX-2: a review from medicinal chemistry perspectives

Inhibitors of COX-2 constitute a class of anti-inflammatory analgesics, showing potential against certain types of cancer. However, such inhibitors are associated with cardiovascular toxicity. Moreover, although single-target molecules possess specificity for particular targets, they often lead to poor safety, low efficacy and drug resistance due to compensatory mechanisms. A new generation of dual-target drugs that simultaneously inhibit COX-2 and another target is showing strong potential to treat cancer or reduce adverse cardiac effects. The present perspective focuses on the structure and functions of COX-2, and its role as a therapeutic target. It also explores the current state and future possibilities for dual-target strategies from a medicinal chemistry perspective.

Novel fused imidazotriazines acting as promising top. II inhibitors and apoptotic inducers with greater selectivity against head and neck tumors: Design, synthesis, and biological assessments

Although the great effectiveness of doxorubicin (Dox) in the treatment of many types of tumors, it showed limited effectiveness against the head and neck squamous cell carcinoma (HNSCC) subtype which is attributed to its reported multiple drug resistance (MDR). In the current study, we considered the essential pharmacophoric features of Dox as an effective Top. II inhibitor and sought to develop a novel set of imidazo[1,2-a] [1,3,5]triazin-2-amines (2a-2p) as a suggested anticancer option that could intercalate the DNA base pairs. We evaluated the % inhibition of the newly synthesized compounds on thirteen cancer cell lines and the analysis of structure-activity relationships revealed that the human head and neck cancer cell line (HNO97) was the most sensitive to their growth inhibition effect. Then, the IC50 values were recorded against the most sensitive cancer cell lines (HNO97, MDA-MB-231, and HEPG2), and compared to the normal cell line OEC (human oral epithelial cells). Compounds 2f and 2g showed very strong activities against HNO97 with IC50 values of (4 ± 1 and 3 ± 1.5 μg/mL), respectively, compared to that of Dox (9 ± 1.6 μg/mL). Next, a quantitative determination of human DNA Top. II concentrations in the most sensitive cell line (HNO97) were recorded for the most active anticancer derivatives. Again, compound 2f showed a superior Top. II inhibition with 87.86% compared to that of Dox (86.44%), while compound 2g achieved an inhibition of 81.37% which was close to the effect of Dox. To further investigate their effects on cell cycle progression and apoptosis induction in HNO97 cells, both 2f and 2g were selected for analysis. Both candidates arrested cell cycle progression at both the S and G2-M phases, as well as increased the early and late apoptosis phase ratios. Besides, both 2f and 2g were subjected to protein expression analysis of apoptosis-related genes (p53, BAX, IL-6, and BCL2). Moreover, the antioxidant effect of 2f and 2g was evaluated by measuring GSH, MDA, and NO markers in HNO97 cells. Furthermore, molecular docking for the newly designed tricyclic derivatives against both the Top. II and DNA double helix was carried out.

In Vitro Evaluation and Bioinformatics Analysis of Schiff Bases Bearing Pyrazole Scaffold as Bioactive Agents: Antioxidant, Anti-Diabetic, Anti-Alzheimer, and Anti-Arthritic

In continuation of our research programs for the discovery, production, and development of the pharmacological activities of molecules for various disease treatments, Schiff bases and pyrazole scaffold have a broad spectrum of activities in biological applications. In this context, this manuscript aims to evaluate and study Schiff base-pyrazole molecules as a new class of antioxidant (total antioxidant capacity, iron-reducing power, scavenging activity against DPPH, and ABTS radicals), anti-diabetic (α-amylase% inhibition), anti-Alzheimer's (acetylcholinesterase% inhibition), and anti-arthritic (protein denaturation% and proteinase enzyme% inhibitions) therapeutics. Therefore, the Schiff bases bearing pyrazole scaffold (22a, b and 23a, b) were designed and synthesized for evaluation of their antioxidant, anti-diabetic, anti-Alzheimer's, and anti-arthritic properties. The results for compound 22b demonstrated significant antioxidant, anti-diabetic (α-amylase% inhibition), and anti-Alzheimer's (ACE%) activities, while compound 23a demonstrated significant anti-arthritic activity. Prediction of in silico bioinformatics analysis (physicochemical properties, bioavailability radar, drug-likeness, and medicinal chemistry) of the target derivatives (22a, b and 23a, b) was performed. The molecular lipophilicity potential (MLP) of the derivatives 22a, b and 23a, b was measured to determine which parts of the surface are hydrophobic and which are hydrophilic. In addition, the molecular polar surface area (PSA) was measured to determine the polar surface area and the non-polar surface area of the derivatives 22a, b and 23a, b. This study could be useful to help pharmaceutical researchers discover a new series of potent agents that may act as an antioxidant, anti-diabetic, anti-Alzheimer, and anti-arthritic.

Design and synthesis of new spirooxindole candidates and their selenium nanoparticles as potential dual Topo I/II inhibitors, DNA intercalators, and apoptotic inducers

A new wave of dual Topo I/II inhibitors was designed and synthesised via the hybridisation of spirooxindoles and pyrimidines. In situ selenium nanoparticles (SeNPs) for some derivatives were synthesised. The targets and the SeNP derivatives were examined for their cytotoxicity towards five cancer cell lines. The inhibitory potencies of the best members against Topo I and Topo II were also assayed besides their DNA intercalation abilities. Compound 7d NPs exhibited the best inhibition against Topo I and Topo II enzymes with IC50 of 0.042 and 1.172 μM, respectively. The ability of compound 7d NPs to arrest the cell cycle and induce apoptosis was investigated. It arrested the cell cycle in the A549 cell at the S phase and prompted apoptosis by 41.02% vs. 23.81% in the control. In silico studies were then performed to study the possible binding interactions between the designed members and the target proteins.

Design and synthesis of 6-arylpyridine-tethered sulfonamides as novel selective inhibitors of carbonic anhydrase IX with promising antitumor features toward the human colorectal cancer

Hypoxia, a characteristic feature of solid tumors, develops as a result of excessive cell proliferation and rapid tumor growth exceeding the oxygen supply, and can result in angiogenesis activation, increased invasiveness, aggressiveness, and metastasis, leading to improved tumor survival and suppression of anticancer drug therapeutic impact. SLC-0111, a ureido benzenesulfonamide, is a selective human carbonic anhydrase (hCA) IX inhibitor in clinical trials for the treatment of hypoxic malignancies. Herein, we describe the design and synthesis of novel 6-arylpyridines 8a-l and 9a-d as structural analogues of SLC-0111, in the aim of exploring new selective inhibitors for the cancer-associated hCA IX isoform. The para-fluorophenyl tail in SLC-0111 was replaced by the privileged 6-arylpyridine motif. Moreover, both ortho- and meta-sulfonamide regioisomers, as well as an ethylene extended analogous were developed. All 6-arylpyridine-based SLC-0111 analogues were screened in vitro for their inhibitory potential against a panel of hCAs (hCA I, II, IV and IX isoforms) using stopped-flow CO₂ hydrase assay. In addition, the anticancer activity was firstly explored against a panel of 57 cancer cell lines at the USA NCI-Developmental Therapeutic Program. Compound 8g emerged as the best anti-proliferative candidate with mean GI% value equals 44. Accordingly, a cell viability assay (MTS) for 8g was applied on colorectal HCT-116 and HT-29 cancer cell lines as well as on the healthy HUVEC cells. Thereafter, Annexin V-FITC apoptosis detection, cell cycle, TUNEL, and qRT-PCR, colony formation, and wound healing assays were applied to gain mechanistic insights and to understand the behavior of colorectal cancer cells upon the treatment of compound 8g. Also, a molecular docking analysis was conducted to provide in silico insights into the reported hCA IX inhibitory activity and selectivity.

Regio- and Stereoselective Switchable Synthesis of (E)- and (Z)-N-Carbonylvinylated Pyrazoles

Regio- and stereoselective switchable synthesis of (E)- and (Z)-N-carbonylvinylated pyrazoles is first developed by using the Michael addition reaction of pyrazoles and conjugated carbonyl alkynes. Ag₂CO₃ plays a key role in the switchable synthesis of (E)- and (Z)-N-carbonylvinylated pyrazoles. Ag₂CO₃-free reactions lead to thermodynamically stable (E)-N-carbonylvinylated pyrazoles in excellent yields whereas reactions with Ag₂CO₃ give (Z)-N-carbonylvinylated pyrazoles in good yields. It is noteworthy that (E)- or (Z)-N¹-carbonylvinylated pyrazoles are obtained with high regioselectivity when asymmetrically substituted pyrazoles react with conjugated carbonyl alkynes. The method can also extend to the gram scale. A plausible mechanism is proposed on the basis of the detailed studies, wherein Ag⁺ acts as coordination guidance.