Benzoyl Azide Research Articles

An Electrochemical Route to Novel N‐Benzoyl‐1,2,3‐Triazoles and Protein Binding Studies of Selected Triazole Derivatives

An electrochemical, cost‐efficient and atom‐economic method for the synthesis of novel, structurally unique N‐benzoyl‐1,2,3‐triazole derivatives has been developed via cascade oxidation‐ [3+2] dipolar cycloaddition reaction of readily available propargyl alcohol and benzoyl azide. The electro‐oxidation of propargyl alcohol and subsequent cycloaddition was performed in an undivided cell using graphite rod and stainless‐steel plate as inexpensive electrode materials. Numerous 4,5‐disubstituted‐ N‐ benzoyl‐1,2,3‐triazoles may be synthesized from mili to multi‐gram scale employing this protocol. The biological significance of few selected triazole derivatives were evaluated via protein binding studies.

Microwave‐assisted synthesis of 1,4‐disubstituted 1,2,3‐triazole derivatives utilizing NiO/Cu2O nano‐photocatalyst

AbstractBACKGROUNDThe main characteristic features of nickel–copper‐catalyzed azide–alkyne click (Ni‐CuAAC) reactions for production of 1,2,3‐triazoles are regioselectivity and the reaction proceeding under mild conditions. The use of copper salts as catalysts often leads to challenges like contamination of the prepared triazoles. NiO/Cu2O nanocomposites (NCs) were utilized in Ni‐CuAAC reactions as heterogeneous nanocatalysts to achieve the production of some 1,4‐disubstituted 1,2,3‐triazoles in high chemical yields under microwave irradiation.RESULTSThe preparation of NiO/Cu2O NCs was performed through the coprecipitation of NiO nanoparticles on Cu2O surface. The prepared catalyst was used for catalyzing a reaction between benzoyl azides and phenylacetylene under optimized reaction conditions. The NiO/Cu2O NCs exhibited high catalytic activity compared to Cu2O nanoparticles. In addition, by utilizing ethanol–water as the solvent system under microwave irradiation, higher yields and efficient product separation were observed.CONCLUSIONThis study investigated the proficiency of NiO/Cu2O NCs as effective nanocatalysts for the selective synthesis of some 1,4‐disubstituted 1,2,3‐triazole derivatives. Employing heterogeneous nanoparticle catalysts, such as Cu2O and NiO/Cu2O, offers several advantages over homogeneous catalytic systems. These include easier catalyst separation and recovery, potential for catalyst reuse and the ability to fine‐tune the catalytic properties by modulating the nanoparticle composition and structure. © 2024 Society of Chemical Industry (SCI).

α-Cleavage of 2,2-Diazido-2,3-dihydroinden-1-one in Solution and Cryogenic Matrices.

The Norrish type I (α-cleavage) reaction is an excellent photochemical method for radical-pair formation in solution. However, in cryogenic matrices, the starting material typically re-forms before the radical pair diffuses apart. This study focused on N2 extrusion from an azido alkyl radical to prevent radical-pair recombination. Irradiation of 2,2-diazido-2,3-dihydroinden-1-one (1) in methanol mainly yielded methyl 2-cyanomethylbenzoate (2) and 2-cyanomethylbenzoic acid (3) via α-cleavage. Laser flash photolysis of 1 in argon-saturated acetonitrile resulted in α-cleavage to form triplet biradical 31Br1 (λmax ∼ 410 nm, τ ∼ 400 ns). In contrast, upon irradiation in glassy 2-methyltetrahydrofuran matrices, triplet alkylnitrene 31N was directly detected using electron spin resonance (D/hc = 1.5646 cm-1, E/hc = 0.00161 cm-1) and absorption spectroscopy (λmax = 276 and 341 nm). Irradiation of 1 in argon matrices generated 31N, benzoyl azide 4, singlet benzoylnitrene 14N, and isocyanide 5, as revealed by IR spectroscopy. The experimental results supported by density functional theory calculations [B3PW91/6-311++G(d,p)] suggest that irradiation of 1 in matrices results in α-cleavage to form biradical 31Br1, which extrudes N2 to yield 31Br2. Rearrangement of 31Br2 into 31N competes with cleavage of a N3 radical to form radical 1Ra3. The N3/1Ra3 radical pair combines to form 4, which upon irradiation yields 14N and 5.

Visible light-driven photocatalytic benzoyl azides formation from benzotrichlorides using rhodium ion modified TiO2

Visible light-driven benzoyl azides formation catalyzed by a rhodium ion modified TiO2 (Rh3+/TiO2) is reported. The Rh3+/TiO2 was prepared as a visible light responsive photocatalyst by a simple procedure from TiO2 and RhCl3･3H2O. The Rh3+/TiO2 exhibited a broaden visible light absorption from 400 nm to 600 nm. Benzoyl azide formation from a benzotrichloride and a trimethylsilyl azide (TMS-N3) was performed catalyzed by the Rh3+/TiO2 under visible light irradiation (λ ≥ 420 nm) in air at room temperature. In this reaction, the benzotrichloride was effectively reduced by the single electron transfer (SET) from the Rh3+/TiO2, and the benzoyl azide was produced in 71% yield via the reaction between the benzoyl chloride and TMS-N3. In addition, several benzotrichloride derivatives were applied to this reaction and the corresponding benzoyl azide derivatives were formed in up to 71% yield. A kinetic analysis was also performed on these reactions, and it was suggested that the SET is the rate determining step in this reaction.

A Novel Photoinduced Ligation Approach for Cross-Linking Polymerization, Polymer Chain-End Functionalization, and Surface Modification Using Benzoyl Azides.

Various ligation processes have recently become a powerful tool in synthetic polymer chemistry. Herein, the use of a new photochemical ligation process as a versatile approach for the cross-linking polymerization, functionalization of polymer chain ends, and surface modification of various materials such as silica and graphene oxide, is demonstrated. The process is based on the formation of urethane linkages by the reaction of photochemically in situ generated isocyanates from benzoyl azides with hydroxyl moieties in the presence of organobase, bicyclo[2.2.2]-1,4-diazaoctane (DABCO) under ambient conditions. The intermediates and obtained materials are characterized by NMR, FTIR, TGA, and TEM analyses. It is believed that this simple and efficient ligation process will expand future applications to fabricate complex macromolecular structures, biomaterials, and gels.

Visible Light-Induced Regioselective Cycloaddition of Benzoyl Azides and Alkenes To Yield Oxazolines

Visible light catalysis allows the regioselective synthesis of oxazolines in high yields. The mild photosensitized manifold leverages the intermolecular formation of oxazolines with a wide functional group tolerance on both benzoyl azides and alkenespartners. Mechanistic investigations suggest the sensitization of the azide moiety as the key activation step.

AuBr3 -Catalyzed Chemoselective Annulation of Isocyanates with 2H-Azirine.

The chemoselective cyclization of isocyanates with 2H-azirine was achieved with AuBr3 as catalyst. This transfer sets the stage for the synthesis of aromatic oxazole-ureas in a tandem process. The addition of a catalytic amount of phosphite enhances the process enormously. The reaction can also be performed in a one-pot process using benzoyl azide instead of isocyanate under the same conditions. A detailed study on the role of the phosphite that was applied as an additive revealed that only non-coordinated phosphite can reduce gold(III) and that gold(I) coordinated phosphite is not oxidized. Accompanied by the reduction of gold, HBr is generated in situ, which turned out to be the actual promotor in combination with the remaining AuBr3 . The positive effect of acid can be explained by a strong N-Au coordination, which tends to break more easily in the presence of small amount of protic acid in the reaction solution.

Glucokinase Activators Based on N-Aryl-N′-Pyridin-2-Ylurea Derivatives

A series of previously undescribed N-aryl-N′-pyridin-2-ylureas were prepared via the reaction of 2-aminopyridines with benzoyl azides and tested in vitro as activators of glucokinase. Statistically significant reductions of glucose levels as compared with controls were demonstrated for several compounds.

Активаторы глюкокиназы на основе производных <I>N</I>-арил-<I>N</I>’-пиридин-2-илмочевины

В эксперименте in vitro изучено активирующее действие по отношению к глюкокиназе ряда ранее неописанных N-арил-N’-пиридин-2-илмочевин, полученных взаимодействием пиридинаминов-2 с бензоилазидами; для некоторых соединений показано достоверное снижение уровня глюкозы по сравнению с контролем.

Recyclable Polymer-Supported Terpyridine–Palladium Complex for the Tandem Aminocarbonylation of Aryl Iodides to Primary Amides in Water Using NaN3 as Ammonia Equivalent

Primary aromatic amides are valuable compounds, which are generally prepared via Beckmann rearrangement of oximes and the hydration of nitriles in organic solvents. We investigated the environmentally friendly catalytic aminocarbonylation in water. Thus, a novel heterogeneous transition-metal catalyst, a polymer-supported terpyridine–palladium(II) complex, was prepared and found to promote azidocarbonylation of aryl iodides with NaN3 and to reduce the generated benzoyl azides in water under CO gas to yield primary aryl amides with high to excellent yield in a one-pot reaction. The catalyst was recovered and reused several times with no loss of catalytic activity.

Visible light sensitization of benzoyl azides: cascade cyclization toward oxindoles via a non-nitrene pathway.

Visible light sensitization of benzoyl azides was examined in reaction with N-phenylmethacrylamides to afford biologically important oxindoles and spirooxindoles via a cascade cyclization under mild reaction conditions. Mechanistic studies suggested a non-nitrene pathway, where triplet benzoyl azides act as the reactive intermediate.

ChemInform Abstract: Unprecedented Transformation of a Directing Group Generated in situ and Its Application in the One‐Pot Synthesis of 2‐Alkenyl Benzonitriles.

AbstractAn unprecedented protocol for the transformation of benzoyl azides (I) into benzonitrile derivatives (II) via iminophosphoranes generated in situ is described.

New poly(ether urethane)s based on lignin derived aromatic chemicals via A-B monomer approach: Synthesis and characterization

ω-Hydroxyalkyleneoxy benzoyl azides were synthesized starting from lignin-derived phenolic acids (vanillic acid and syringic acid) and ω-haloalkanols (6-chlorohexanol and 11-bromoundecanol). These bio-derived A-B monomers were self-polycondensed to afford poly(ether urethane)s which exhibited reasonably high molecular weights (ηinh=0.41–0.69dLg−1 and Mn,GPC=20,000–40,400) and film forming characteristics. Poly(ether urethane) films exhibited % transmittance at 800nm in the range 80.2–87.6. Poly(ether urethane)s were stable up to 320–340°C and showed Tg values in the range 40–70°C. Tg values of poly(ether urethane)s were dependent on length of oxyalkylene spacer and number of methoxy substituents on aromatic ring. Thus, vanillic acid and syringic acid were demonstrated to be valuable starting materials for synthesis of bio-based poly(ether urethane)s.

Study of Sustainability and Scalability in the Cp*Rh(III)-Catalyzed Direct C–H Amidation with 1,4,2-Dioxazol-5-ones

The practical aspects of Cp*Rh(III)-catalyzed direct C–H amidation with 1,4,2-dioxazol-5-ones were investigated on the operational safety, use of green solvent, and scalability. Differential scanning calorimeter (DSC) measurement showed that 3-phenyl-1,4,2-dioxazol-5-one is thermally stable while benzoyl azide, a conventionally employed precursor of acyl nitrene, rapidly decomposes to isocyanate. It was confirmed that the replacement of acyl azide with 1,4,2-dioxazol-5-one brings not only high reactivity but also improvement in safety. In respect to a green process development, functional group tolerant Cp*Rh(III) catalyst exhibited high reactivity in ethyl acetate, successfully replacing 1,2-dichloroethane solvent used in the original report. Upon the validation on safety and environmental concerns, scalability was also tested. Two different types of arenes bearing pyridyl and oxime directing groups showed excellent conversions on tens of gram scale reactions, and single recrystallization gave desired pr...

Unprecedented Transformation of a Directing Group Generated In Situ and Its Application in the One-Pot Synthesis of 2-Alkenyl Benzonitriles.

An unprecedented protocol for the transformation of benzoyl azides into benzonitrile derivatives via iminophosphoranes generated in situ is described. The strategy was successfully applied to the de-novo synthesis of 2-alkenylated benzonitrile derivatives from benzoyl azides through ortho C-H activation/alkenylation followed by subsequent rearrangement. The salient features of this protocol involve incorporation of two important functionalities through cyanation and olefination in one pot under mild reaction conditions by using a less expensive Ru catalyst. The mechanism was established by isolating and characterising (using (31) P NMR) an intermediate with two ortho functionalities, iminophosphorane and olefin, under specific reaction conditions.

Visible light C-H amidation of heteroarenes with benzoyl azides.

Benzoyl azides were used for the direct and atom economic C-H amidation of electron rich heteroarenes in the presence of phosphoric acid, a photocatalyst and visible light. Hetero-aromatic amides are obtained in good yields at very mild reaction conditions with dinitrogen as the only by-product. The reaction allows the use of aryl-, heteroaryl- or alkenyl acyl azides and has a wide scope for heteroarenes, including pyrroles, indole, furan, benzofuran and thiophene giving good regio-selectivities and yields.

ChemInform Abstract: Metal‐Mediated Reactions of Aryl Isocyanates with Dimethoxycarbene to Form Isatin Derivatives.

AbstractConditions which involve Cu(II) catalysis are developed to control the reaction of aryl isocyanates or analogous benzoyl azides with dimethoxycarbene for the formation of isatin derivatives.

Rapid and facile synthesis of acyl azides from acyl halides using a polymer-supported azide ion under heterogeneous conditions

In this article a rapid and facile method for synthesis of acyl azide is described. The cross-linked poly(N-methyl-4-vinylpyridinium) azide ion, [P4-VP]N3 is prepared and used as an efficient polymeric reagent for synthesis of acyl azides from acyl halides at room temperature under heterogeneous conditions. Various benzoyl halides, with electron-withdrawing groups as well as electron-donating groups, were transformed into the corresponding benzoyl azides in high to excellent yields in short reaction times. The acyl azide products were characterized by FT-IR, and some of them were also characterized by 1H-and/or 13C-NMR spectroscopy, and physical properties were compared to literature values of known compounds. The spent polymeric reagents can be regenerated and reused for several times without losing their activity. Relative to the reported methods, the present method has the advantages of operational simplicity, mild reaction conditions, fast reaction rates, simple reaction work-up and lower hazardous and potentially explosive nature. Also the present method is the first procedure for the synthesis of acyl azides from acyl halides by using a polymer-supported azide ion under heterogeneous conditions.

Orthoamide und Iminiumsalze, LXXXII [1]. Die Spaltung von Alkincarbonsäure-orthoamiden mit Trimethylsilylazid / Orthoamides and Iminium Salts LXXXII [1]. The Cleavage of Orthoamides of Alkynecarboxylic Acids by Trimethylsilyl Azide

The cleavage of orthoamides of alkynecarboxylic acids 5 with trimethylsilyl azide affords 4-[bis(dimethylamino)methylene]-4H-1,2,3-triazoles 9. By treatment of the bis-orthoamide of acetylenedicarboxylic acid 1 with trimethylsilyl azide and benzoyl azide, respectively, the 5- [bis(dimethylamino)methylene]-5H-1,2,3-triazole carboxamidinium salt 12a is accessible. Iminium salts 10 and 14 can be prepared by methylation of the triazoles 9 and 12a in 2-position of the triazole ring. The crystal structure of 5H-1,2,3-triazole-4-carboxamidinium tetraphenylborate 12b is reported

Quantum chemical study of the arylacyl azide complexes with Lewis acids and their Curtius rearrangement to isocyanates

The structures of donor-acceptor complexes of syn-benzoyl azide, its 2-methyl- and 2,6-dimethyl-substituted derivatives with BF3, AlCl3, and SbCl5, and the corresponding transition states of the rearrangement into isocyanates were studied by the PBE/TZ2P method in the framework of the density functional theory (DFT). The complexes are formed at the oxygen and nitrogen atoms of the acyl azide group and have the composition 1: 1 or 1: 2 depending on the Lewis acid (L) structure. The complexes at the oxygen atom are more stable; the most stable complexes are formed by the reactions of acyl azides with AlCl3. Complex formation with Lewis acids decreases the activation energy of the transformation of acyl azides into isocyanates owing to the +M effect and stabilization of the Ar-C(O-L(1−))=N(1)-N(2)(1+)≡N(3) mesomeric form. The activation energy decreases with an increase in the number of ortho-methyl substituents in benzoyl azide due to the +I effect of the phenyl group. The turn of the phenyl ring at almost 90° with respect to the CON3 group is needed for the rearrangement to occur, and the energy necessary for this process is ∼8 kcal mol−1.