Knoevenagel Condensation Products Research Articles

Extending the Carbon Chain Length of Carbohydrate-Derived 5-Substituted-2-furaldehydes by Condensing with Active Methylene Compounds under Organocatalytic Conditions.

This work reports a high-yielding, organic solvent-free, gram-scale synthesis of novel Knoevenagel condensation products by reacting carbohydrate-derived 5-substituted-2-furaldehydes (SFLs) with active methylene compounds (AMCs) using various organic amines and inorganic bases as catalysts. Among the base catalysts examined, piperidine performed best, affording satisfactory selectivity and yield of the targeted Knoevenagel condensation products owing to the subtle balance between its nucleophilicity and basicity. The reaction was optimized on various reaction parameters, such as temperature, duration, solvent, catalyst loading, and molar ratio of the reactants. Even though the SFLs exhibited significantly different reactivity, a general synthetic protocol was developed successfully, affording good to excellent isolated yields (70-96%) of the novel Knoevenagel condensation products at ambient temperature. Moreover, the Knoevenagel products were purified by triturating with eco-friendly solvents (e.g., ethyl acetate and n-heptane) without chromatographic purification.

Revisiting hydrotalcite synthesis: Efficient combined mechanochemical/coprecipitation synthesis to design advanced tunable basic catalysts

Abstract Hydrotalcite materials (HTs) were synthesized by a facile and swift combined mechanochemistry/coprecipitation approach, and their catalytic activity was evaluated and compared with conventionally synthesized hydrotalcites (co-precipitation method) in the Knoevenagel condensation between furfural and ethyl cyanoacetate/malononitrile. Characterization and catalytic activity results clearly demonstrate that the proposed combined mechanochemical/coprecipitation approach provides an improvement in crystallinity, morphology, tunable basicity, and textural properties (higher surface area and enhanced surface properties) as compared to HTs obtained via conventional coprecipitation methods. In addition, mechanochemically synthesized HTs largely improve catalytic activities, including conversion and product selectivity to Knoevenagel condensation products under solventless conditions, short reaction times, or reaction at room temperature as compared to conventional counterparts (e.g., 30–40 vs > 99% product yields).

Advances in the Synthesis of Heterocycles with Two and Three Heteroatoms using Hydrazonoyl Halides

AbstractThe review covers the results of studies published in the literature on the use of hydrazonoyl halides in the synthesis of five‐ (pyrazoles, thiazoles, triazoles, oxa‐ and thiadiazoles), six‐ (oxa‐ and thiadiazines, indazoles, pyridazines, pyrazines, tetrazines) or seven‐membered (benzotriazepine) heterocycles. In the formation of these heterocycles, the main intermediate stage of the reaction is the in situ generation of nitrilimine, which enters into a cycloaddition reaction with substituted acetylenes (including in situ generated benzynes, naphthynes), allenes, activated olefins, anthranilic acid derivatives, organosulfur compounds (mercaptoaldehydes, mercaptocarboxylic acids) or with fused heterocycles. Examples are given of the formation of heterocycles by replacing the halogen atom from a hydrazonoyl halide molecule with a nucleophilic group, followed by exhaustive intramolecular cyclization into the target compound. There are discussions of reactions in which the cycloaddition of the nitrilimine to the in situ synthesized Knoevenagel condensation product (from CH‐acid compounds, such as di‐ and monocarbonyl compounds, dinitrile malonic acid) occurs, leading to spiro‐linked or conventional pyrazoles. Some syntheses of biologically active representatives are shown.

Highly efficient CdS/CeO2/Ag3PO4 nanocomposite as novel heterogenous catalyst for Knoevenagel condensation and acetylation reactions

In light of environmental and economic concerns, the use of heterogeneous catalysts that can function under gentler reaction conditions has recently become popular. In this study by using the precipitation method, CdS/CeO2/Ag3PO4 ternary nanocomposites with varied molar proportions of CdS:CeO2/Ag3PO4 were produced. The catalysts' surface functional groups; morphology and crystal structures were examined using FTIR, SEM-EDX and XRD respectively. The catalytic efficiency of all synthesized nanomaterials was tested on a model Knoevenagel condensation reaction. For the best catalyst, selected from the screening, the optimization of reaction conditions such as the solvent, catalyst load, concentration of reagents such as malononitrile/acetic anhydride, and temperature. The ternary nanocomposite CdS/CeO2/Ag3PO4 (4:1) displayed higher catalytic activity (95.4 ± 3.2 %) than the rest of the nanomaterials prepared. Thus, the ternary nanocomposite CdS/CeO2/Ag3PO4 with 4:1 mol ratio with optimized reaction conditions was used to check the substrate scope of Knoevenagel condensation and acetylation reaction. The synthesized Knoevenagel condensation and acetylation reaction products were also characterized by proton and carbon NMR for their structure determination. The nanocomposite's reusability was carried out and only 7.5 ± 2 % decrement was witnessed after four runs and 23.3 % after the fifth run. and this indicates the potential application of the catalyst to organic reactions. Furthermore, we have proposed the possible catalytic mechanisms for both organic reactions.

Nitrogen-Enriched Biguanidine-Functionalized Cobalt Ferrite Nanoparticles as a Heterogeneous Base Catalyst for Knoevenagel Condensation under Solvent-Free Conditions.

Designing efficient, economical heterogeneous catalysts for the Knoevenagel condensation reaction is highly significant owing to the importance of reaction products in industries as well as pharmaceutics. Herein, we have designed and synthesized biguanidine-functionalized basic magnetically retrievable cobalt ferrite nanoparticles (CFNPs) for the synthesis of Knoevenagel condensation products using benzaldehydes and active methylene compounds (malononitrile/ethyl cyanoacetate/cyanoacetamide). Several advanced techniques, such as Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and vibration sample magnetometry (VSM), were utilized to precisely characterize the catalyst. The robust features of the current approach involve outstanding catalytic performance, solvent-free reaction conditions, ease of catalyst retrievability, easy workup procedure, large substrate tolerance, high turnover frequency (TOF) values (up to 486.88 h-1), values of green chemistry metrics such as E-factor (0.15), reaction mass efficiency (RME) value (87.07%), carbon efficiency (93.4%), and atom economy (AE) value (88.10%) close to their ideal values, and recyclability up to eight runs without a considerable reduction in activity, boosting the appeal of this approach from a commercial and ecological point of view.

7-(2-aryl-1-cyanovinyl)-1,2,3,4-tetrahydropyrazolo[1,5-<i>a</i>][1,3,5]triazine-8-carbonitriles: synthesis and biological activity

A new method was proposed for the preparation of 5-amino-3-(cyanomethyl)-1 H -pyrazole-4-carbonitrile by reacting the potassium salt of malononitrile dimer with hydrazinium sulfate. The reaction of 5-amino-3(cyanomethyl)-1 H -pyrazole-4-carbonitrile with aromatic aldehydes in the presence of catalytic amounts of morpholine leads to the formation of Knoevenagel condensation products. Aminomethylation of the resulting ( Z )-5amino-3-(2-aryl-1-cyanovinyl)-1 H -pyrazole-4-carbonitriles with primary aromatic amines and excess aqueous HCHO in refluxing DMF leads to the formation of 7-(2-aryl-1-cyanovinyl)-1,2,3,4-tetrahydropyrazolo[1,5- a ][1,3,5]triazine-8-carbonitriles. Bioavailability parameters were studied in silico , and possible protein targets were predicted by protein-ligand docking. In an in vitro experiment on cultures of E. coli , S. aureus and B. pumilis , 5-amino-3-(cyanomethyl)-1 H -pyrazole-4-carbonitrile does not show any noticeable antibacterial effect. At the same time, three compounds of the pyrazolo[1,5- a ][1,3,5]triazine series showed a pronounced antidote effect against the herbicide 2,4-D on sunflower seedlings in a laboratory experiment, for one compound a noticeable growth-stimulating effect was noted.

Bifunctional metal-organic frameworks as selective turn-on fluorescence sensors for tryptophan and heterogeneous catalysts for Knoevenagel condensation reaction

Two new doubly interpenetrated metal-organic frameworks (MOFs) with formulas [{Zn(L1)(5-nipa)}·DMA]α (1a) and [{Cd(L2)(5-nipa)(H2O)}]α (1b) have been discussed herein, where [L1 = N,N'-(oxybis(4,1-phenylene))diisonicotinamide; L2 = N,N'-(methylenebis(4,1-phenylene)) diisonicotinamide; 5-H2nipa = 5-nitroisophthalic acid; DMA = dimethylacetamide]. A single crystal X-ray analysis reveals that 1a exhibits a 2D-interpenetrated interwoven sheet and finally adapts a 3D framework structure with the help of π···π stacking interactions. Similarly, 1b displays a two-fold interpenetrated 2D sheet-like architecture and is finally adjusted to a 3D structure. Both 1a and 1b feature channels with a cross-section of 25.06 × 25.06 Å2 and 24.01 × 24.01 Å2, respectively, running along the b-axis. Topological analysis of 1a and 1b by ToposPro suggests a (4)-connected uninodal sql topology with point symbol {44.62}. Further, 1a and 1b were exploited as molecular sensors for several amino acids exposing different shapes and sizes and exhibiting selective turn-on fluorescence sensing towards biologically important D/L-tryptophan with the notable limit of detection values of 0.084/0.110 μM and 0.143/0.141 μM, respectively, in aqueous medium. In addition, 1a and 1b were also exploited as heterogeneous catalysts towards several assorted aldehydes having different electronic environments, including sterically demanding aldehydes, under mild reaction conditions and obtained up to 97% of the respective Knoevenagel condensation product. Importantly, sterically hindered aldehydes also worked well with the MOF catalysts 1a and 1b, but showed comparatively low conversion. It is important to mention that in both cases, these MOF materials are recyclable for up to five consecutive runs without displaying any substantial loss in their sensing or catalytic activities. Moreover, the present investigation cultivates a new vision to design novel luminescent MOFs that can be used as multifunctional materials for the turn-on sensing of small organic molecules as well as instigated as heterogeneous catalysts in diverse organic transformation reactions.

Microwave-accelerated Eco-friendly Performance of the Knoevenagel Condensation Reaction with Various Active Methylene Derivat-ives evaluation of Electrochemical Properties

Background: The present work describes sustainable Knoevenagel condensation reac-tion of aryl/ heterocyclic aldehyde with various active methylene derivatives such as malono-nitrile, dimedone, ethyl cyanoacetate, ethyl acetoacetate, barbituric acid, and thiobarbituric acid is reported. The protocol was developed using water extract of mango peel ash (WEMPA), an agro-waste that emerged as a greener solvent media and in combination with microwave irradiation gave high-yield product isolation. The method noticed added advantages for the reaction faster reaction rate, inexpensive extract media, simple work-up, and not required chromatographic puri-fication. The present method synthesized various Knoevenagel condensation derivatives benzyli-dinemalononitrile, ethyl benzylidenecyanoacetate, ethyl benzylideneacetoacetate, benzalbarbituric acid, benzylidene-2-thiobarbituric acid, and 5,5-dimethylcyclohexane-1,3-diones were character-ized by FT-IR, 1H- & 13C-NMR, and mass spectrometry. Further, selected derivatives were inves-tigated for their electrochemical studies using cyclic voltammetry, and showed comparable oxida-tion and reduction potential properties. Objective: The objective of this work is to develop a green methodology synthesis of various active methylene derivatives via Knoevenagel condensation to give the product of benzylidine-malononitrile, ethyl benzylidenecyanoacetate, ethyl benzylideneacetoacetate, benzalbarbituric acid, benzylidene-2-thiobarbituric acid and 5,5-dimethylcyclohexane-1,3-diones. Methods: We have demonstrated WEMPA as a greener homogenous agro-waste catalytic medi-um for the economic synthesis of Knoevenagel condensation products. The developed method was found robust, non-toxic and solvent-free with a simple work-up to give the target product. The selected derivatives were investigated for their electrochemical studies using the cyclic volt-ammetry method. Results: The agro-waste-based catalyst developed avoids the use of the external organic or inor-ganic base for the Knoevenagel condensation reaction under microwave irradiation. The de-scribed method found faster, eco-friendly, simple filtration and recrystallization excellent yield, and purity of the Knoevenagel product. Further, the selected compounds (8a-8d, 9a- 9d, 10a-10d, 11a,-11c, 12a, 12b, and 13a-13c) were subjected to electrochemical behavior studies and showed good oxidation and reduction properties. Conclusion: In summary, we have established an efficient, simple, inexpensive agro-waste based catalytic approach for the synthesis of benzylidinemalononitrile, ethyl benzylidenecyanoacetate, ethyl benzylideneacetoacetate, benzalbarbituric acid, benzylidene-2-thiobarbituric acid and 5,5-dimethylcyclohexane-1,3-diones derivatives under microwave irradiation described. The catalyst is agro-waste derived, which is abundant in nature and recyclable without loss of activity after the four-run of the reaction, thus making the present approach a greener one. The advantages of the approach are inexpensive, chemical base free, requiring no external metal catalyst, short reaction time, and simple work-up isolated excellent yields of the product. For the first time, herein, we reported the electrochemical behavior of the products prepared, and showed good oxidation and reduction properties, and these molecules will emerge as good antioxidant agents. other: NA

Synthesis of novel pyrimido[4,5-e]indolizine- and pyrimido[5,4-c]quinolizine-6-carboxylic acids

An effective method for the synthesis of previously undescribed 1,3,4,5,6a,7,8,9-octahydropyrimido[4,5-e]indolizine- and 1,3,4,5,7,8,9,10-octahydro-2H-pyrimido[5,4-c]quinolizine-6-carboxylic acids by hydrolysis and decarboxylation of new spiro-substituted derivatives was proposed. The corresponding spirocyclic derivatives were obtained by boiling of 6-dialkylamino-1,3-dimethyl-5-formyluracils with Meldrum's acid in acetonitrile. The reaction proceeds according to the tert-amino effect mechanism without the release of Knoevenagel condensation products

Syntheses of gold supported on metal oxides and their application in organic transformations

Herein, we report a general and straightforward synthesis method for gold supported on mesoporous and microporous metal oxides. Supported materials, in general, show higher crystallinity compare to unsupported systems as verified through powder X-ray diffraction (XRD). Also, through XRD, most of the metal is observed to be in its oxide form, whereas the gold support was found to be in its metallic state, which has been further confirmed from TEM. In terms of surface area, the catalyst was not found to follow any trend. Morphology wise, there are no changes observed after doping except in few cases. Combined results from XRD, X-ray fluorescence spectroscopy, Auger, and X-ray photoelectron spectroscopy suggest that gold is mainly in the bulk and very little (0.04% in case of gold doped calcium oxide) or non (in case of gold doped mixed manganese-cerium oxide) on the surface. The presence of Au (0) 4f peaks in XPS further confirms the metallic state of the gold. Oxides of indium, magnesium and calcium have been studied for the organic transformation reactions. An enhancement in activity and product selectivity was observed in the case of the gold supported catalysts. Indium serves as a great catalyst for C–C coupling and electrophilic aromatic substitution reactions and gives >99% conversion. Interestingly, 88% selectivity for C–C coupling and >99% selectivity for aromatic substitution have been achieved at 100 °C and room temperature respectively. Magnesium and calcium give Knoevenagel condensation products. At room temperature with very low catalyst loading, >99% conversion and selectivity were observed for the Knoevenagel reaction with as high as 35.30 TOF. A mechanism for the C–C coupling reaction has been proposed based on these results. The general and straightforward synthesis of gold promoted mesoporous and microporous metal oxides were templated using Pluronic P123 surfactant via inverse micelle formation. These catalysts were scanned for the various organic transformation reactions and enhanced activity was shown in the case of gold promoted catalysts. • A general and straightforward synthesis method for gold support mesoporous and microporous metal oxides. • An improvement in metal oxide crystallinity as a result of gold doping. • An enhancement in activity and product selectivity due to the gold supported catalysts. • Indium based C–C coupling and electrophilic aromatic substitution reactions that give >99% conversion. • High selectivity and high conversion for Knoevenagel ester condensation with very low catalyst loading.

Contribution of Knoevenagel Condensation Products toward the Development of Anticancer Agents: An Updated Review.

Knoevenagel condensation is an entrenched, prevailing, prominent arsenal following greener principles in the generation of α, β-unsaturated ketones/carboxylic acids by involving carbonyl functionalities and active methylenes. This reaction has proved to be a major driving force in many multicomponent reactions indicating the prolific utility toward the development of biologically fascinating molecules. This eminent reaction was acclimatised on different pharmacophoric aldehydes (benzimidazole, β-carboline, phenanthrene, indole, imidazothiadiazole, pyrazole etc.) and active methylenes (oxindole, barbituric acid, Meldrum's acid, thiazolidinedione etc.) to generate the library of chemical compounds. Their potential was also explicit to understand the significance of functionalities involved, which thereby evoke further developments in drug discovery. Furthermore, most of these reaction products exhibited remarkable anticancer activity in nanomolar to micromolar ranges by targeting different cancer targets like DNA, microtubules, Topo-I/II, and kinases (PIM, PARP, NMP, p300/CBP) etc. This review underscores the efficiency of the Knoevenagel condensation explored in the past six-year to generate molecules of pharmacological interest, predominantly toward cancer. The present review also provides the aspects of structure-activity relationships, mode of action and docking study with possible interaction with the target protein.

Pseudo-five-component organocatalyzed synthesis of dicyanoanillines using only malononitrile and aromatic aldehydes

A pseudo-five-component reaction leading to efficient synthesis of dicyanoanillines was developed using only aromatic aldehydes and malononitrile as the starting reactants. Mechanistic studies suggested that a malononitrile dimer and the Knoevenagel condensation product of benzaldehyde, initially formed in the reaction mixture, combine with a fourth equivalent of malononitrile to form the final product. X-ray crystallography analysis of one of the derivatives confirmed the structure of the products.

Base and metal free true recyclable medium for Knoevenagel condensation reaction in SDS-ionic liquid-aqueous miceller composite system

This paper presents for the first time a base and metal free procedure for Knoevenagel condensation reaction in a neutral medium comprises water-SDS-imidazolium ionic liquid composite system. Knoevenagel condensation products from the different aromatic aldehydes and active methylene compounds such as malononitrile, ethyl cyanoacetate or cyano acetic acid provides good to excellent yields in all cases examined at 80 °C. The developed protocol has several advantages such as chromatography and organic volatile solvent free protocol, short reaction time and recyclability of catalyst including reaction waste. The reaction is believed to proceed in the hydrophobic cavity of the micelle formed in the medium which was proved by dynamic light scattering studies.

Recent development of green protocols towards Knoevenagel condensation: A Review

A large number of varied synthetic strategies for carbon-carbon bond formation have been proposed by researchers from time to time. Knoevenagel condensation products synthesized by green protocol have been highly appreciated, Knoevenagel products find enormous application in therapeutics and pharmacological. Green synthetic strategies like ionic liquid media, solvent free condition, use of aqueous media and utilization of nano particles towards synthesis of Knoevenagel products have been recently utilized by scientist all over the world. In this study we highlight the recent development of green methods for Knoevengal condensation product formation.

Synthesis and Anticonvulsant Activity of Some Cyclohexanone Derivatives – Knoevenagel Condensation Products

Aseries of diethyl esters of 2-aryl-4-hydroxy-4-methyl-6-oxocyclohexane-1,3-dicarboxylic acids (β-cycloketols) were synthesized by Knoevenagel condensation. A method for their dehydration was developed. Peculiarities of the condensation depending on the reaction conditions were pointed out. All obtained cycloketols and some dehydrated analogs exhibited more or less pronounced anticonvulsant activity in the corazole seizure test in mice.

Novel tandem Knoevenagel-Michael condensation product of naphtho[2,1-b]furan-2-carbaldehyde with dimedone: Synthesis, spectroscopic and crystal structure studies

Abstract 2,2′-Napthfuranyl bis(3‑hydroxy-5,5-dimethyl-2-cyclohexene-1-one) (2) was obtained in one pot via condensation between naphtho[2,1-b]furan-2-carbaldehyde (1) and dimedone. Instead of the Knoevenagel condensation product, (2) was obtained via tandem Knovenegel-Michael reaction. The reaction went effortlessly even in the absence of a strong base/catalyst and in short duration. Cyclisation of (2) to yield the expected xanthene derivative did not occur even after the reflux was carried out with Conc. HCl and H2SO4. The crystal structure of (1) was studied by single crystal X-ray diffraction technique (SCXRD). Further, (2) was characterized by FTIR, 1H & 13C NMR, mass spectral analysis, and, further by SCXRD. Crystal structure of (1) features several CH…O, CH…π and many π…π interactions resulting in a complex three dimensional (3D) architecture, while, in (2), whose molecular conformation is stabilized by two intramolecular OH…O hydrogen bonds, CH…O and π…π interactions form 1D ribbon like architecture. Hirshfeld surface analyses were also performed.

Identification of new biomarkers of pyridoxine-dependent epilepsy by GC/MS-based urine metabolomics

α-Aminoadipic semialdehyde and its cyclic form (Δ1-piperideine-6-carboxylate) accumulate in patients with α-aminoadipic semialdehyde dehydrogenase (AASADH; antiquitin; ALDH7A1) deficiency. Δ1-Piperideine-6-carboxylate is known to react with pyridoxal 5'-phosphate (PLP) to form a Knoevenagel condensation product, resulting in pyridoxine-dependent epilepsy. Despite dramatic clinical improvement following pyridoxine supplementation, many patients still suffer some degree of intellectual disability due to delayed diagnosis. In order to expedite the diagnosis of patients with suspected AASADH deficiency and minimize the delay in treatment, we used gas chromatography-mass spectrometry-based metabolomics to search for potentially diagnostic biomarkers in urine from four patients with ALDH7A1 mutations, and identified Δ2-piperideine-6-carboxylate, 6-oxopipecolate, and pipecolate as candidate biomarkers. In a patient at postnatal day six, but before pyridoxine treatment, Δ2-piperideine-6-carboxylate and pipecolate were present at very high concentrations, indicating that these compounds may be good biomarkers for untreated AASADH deficiency patients. On the other hand, following pyridoxine/PLP treatment, 6-oxopipecolate was shown to be greatly elevated. We suggest that noninvasive urine metabolomics screening for Δ2-piperideine-6-carboxylate, 6-oxopipecolate, and pipecolate will be useful for prompt and reliable diagnosis of AASADH deficiency in patients within any age group. The most appropriate combination among Δ2-piperideine-6-carboxylate, 6-oxopipecolate, and pipecolate as biomarkers for AASADH deficiency patients appears to depend on the age of the patient and whether pyridoxine/PLP supplementation has been implemented. We anticipate that the present bioanalytical information will also be useful to researchers studying glutamate, proline, lysine and ornithine metabolism in mammals and other organisms.

Crystal and Molecular Structure Analysis in Knoevenagel Condensation Product of Substituted Napthofuran-2-Carbaldehydes

In the current study, two novel Knoevenagel condensation products of substituted napthofuran-2-carbaldehydes were designed, synthesized and characterized. In order to study the intermolecular interactions of title compounds, single crystals were grown by slow evaporation solution growth technique at room temperature and crystal structure has been determined by single crystal X-ray diffraction technique. Both the molecules crystallize in the monoclinic centrosymmetric space group P21/c with one molecule in the asymmetric unit. In compound [4] the molecules are connected via bifurcated C-H···O=C and C-H···N=C H-bonds and van der Waals interactions forming a layered structure, whereas in compound [5a] the molecular conformation is stabilized via intramolecular C-H···O H-bond and molecule interacts with other molecule generated via 21-screw via bifurcated C-H···O=C along with C-H···N=C H-bonds, which are interacting with nitro- of other molecule generated via same symmetry operation, forming bifurcated C-H···O-N H-bonds, which helps in formation of molecular sheet-like structure.Further, in order to understand the various types and nature of intermolecular interactions in the supramolecular structure Hirshfeld surface analysis and fingerprint plot analysis was carried out.

Synthesis of Functionalized Bicyclic Compounds Based on 2-(1-Arylethylidene)malononitriles

New tetrahydroisoquinoline-5,7-dicarbonitrile derivatives have been synthesized by piperazine hydrate-catalyzed reaction of acetoacetanilide with 2-(1-arylethylidene)malononitriles (Knoevenagel condensation products of acetophenones and malononitrile) in aqueous ethanol at room temperature. The product structure was confirmed by NMR spectra and X-ray analysis of 1,6-diamino-4a-methyl-3-oxo-2,8-diphenyl-2,3,4,4a-tetrahydroisoquinoline-5,7-dicarbonitrile.

A Synthetic Strategy for the Construction of Functionalized Triphenylene Frameworks via Palladium Catalyzed Intramolecular Annulation/Decyanogenative C-H Bond Alkenylation.

The palladium catalyzed synthesis of 14-phenylbenzo[ f]tetraphene-9-carbonitrile derivatives as core polycyclic aromatic hydrocarbons (PAHs) was achieved via an intramolecular annulation and decyanogenative C-H bond alkenylation strategy. A readily synthesized Knoevenagel condensation product of [1,1'-biphenyl]-2,2'-dicarbaldehyde with benzyl cyanide converted successfully into 14-phenylbenzo[ f]tetraphene-9-carbonitrile derivatives in excellent yields up to 94%. The transformation involves an intramolecular cascade C-C bond formation along with a C-H bond cleavage sequence.