Imidoyl Chlorides Research Articles

Controllable Regioselective [3+2] Cyclizations of N-CF3 Imidoyl Chlorides and Ph3PNNC: Divergent Synthesis of N-CF3 Triazoles.

Presented herein are two distinct regiodivergent [3+2] cyclization reactions between N-CF3 imidoyl chlorides and N-isocyaniminotriphenylphosphorane (NIITP) that include flexible modulation of the electronic properties of NIITP. The regioselectivity of reactions was different in the absence and presence of the Mo catalyst. The approach provides alternative efficient and scalable routes for N-CF3 triazole synthesis, demonstrating a broad substrate scope, excellent functional group tolerance, and practical advantages.

N-CF3 Imidoyl Chlorides: Scalable N-CF3 Nitrilium Precursors for the Construction of N-CF3 Compounds.

A wide range of N-CF3 imidoyl chlorides were synthesized for the first time via the N-trifluoromethylation of nitriles in DCM by using AlCl3-activated PhICF3Cl as the CF3 source. The reactions of them with N-/O-/S-nucleophiles, as well as with 1,3-dipoles, were carried out to efficiently deliver N-CF3 amidines/imidates/thioimidates and N-CF3 azoles, demonstrating that they are a class of scalable NCF3-containing synthons in the synthesis of N-CF3 compounds.

Efficient Synthesis of Fused Heterocycles Incorporating Pyrazole/Thiadiazine or Pyrazole/Thiadiazepine Fragments Using N‐Chlorosulfonyltrihaloacetimidoyl Chlorides

AbstractA novel simple and effective method has been developed for constructing pyrazolothiadiazine and pyrazolothiadiazepine fused heterocycles incorporating an endocyclic sulfonamide fragment. The cyclocondensation of readily available N‐(chlorosulfonyl)imidoyl chlorides, RC(Cl)=NSO2Cl (R=CCl3, CF2Br), with N‐methyl‐substituted 4‐ or 5‐aminopyrazoles results in the formation of isomeric pyrazolothiadiazine‐S,S‐dioxides. Additionally, when 5‐ or 3‐aminoalkyl‐substituted pyrazoles are employed, they serve as 1,4‐N−C−C−C binucleophiles, leading to the synthesis of novel pyrazolothiadiazepine heterocycles. Notably, the trichloromethyl and bromodifluoromethyl substituents in these compounds can be converted into dichloromethyl and difluoromethyl groups, providing enhanced functionalization options.

Reversed-Polarity Synthesis of N-Sulfonyl Ketimines with Imidoylsilanes and Diaryliodonium Salts via Palladium-Catalyzed Reactions.

Imines are important building blocks in organic chemistry. Iminines, aldimines and ketimines, have been traditionally synthesized by the condensation reaction of the corresponding carbonyl compound with an amine moiety. More recently, palladium-catalyzed synthesis of ketimines using imidoyl chlorides has been reported. As an alternative, we report the reversed-polarity synthesis of N-sulfonyl ketimines using an anion equivalent imidoylsilane as a new nucleophilic coupling partner in the presence of a palladium catalyst. To the best of our knowledge, this is the first report of the use of imidoylsilanes in transition-metal-catalyzed coupling reactions. Diaryliodonium salt as an electrophile, various aryl-aryl or heteroaryl-aryl N-sulfonyl ketimines were successfully prepared in up to 99% isolated yields.

1,3-Dipolar cycloaddition of azomethine ylides and imidoyl halides for synthesis of π-extended imidazolium salts

A new synthetic approach to π-extended imidazolium salts is developed based on 1,3-dipolar cycloaddition of polycyclic aromatic azomethine ylides with imidoyl chlorides in the presence of cesium fluoride as a key additive.

Efficient and scalable methods for synthesis of midazolam drug with an annulation process

The reported methods for the synthesis of midazolam include a number of disadvantages, such as high production cost and low yields. The purpose of this investigation was to develop a more economical and technically more feasible route to synthesis of midazolam. In this research, two easy and scalable synthetic methods for the production of midazolam drug are presented. One-pot condensation of imidoyl chloride or 1,4-benzodiazepinic N-nitrosoamidines with carbanion of two isocyanide reagents is described and two important and key tricyclic ring intermediates synthesized. These imidazo-type structures can be derivatives by the alkylation of the imidazole ring with tert-butyl magnesium chloride at 0 °C in excellent yield, which have not been described for these intermediates in the literatures.

Imidoyl Chloride Mediated One-Pot Synthesis of 3-Electron Withdrawing Group Substituted Indoles

Imidoyl Chloride Mediated One-Pot Synthesis of 3-Electron Withdrawing Group Substituted Indoles

Novel Convenient Approach to 6-, 7-, and 8-Numbered Nitrogen Heterocycles Incorporating Endocyclic Sulfonamide Fragment.

A new effective method for the construction of nitrogen heterocycles incorporating endocyclic pharmacophore sulfonamide fragment, based on the use of easy accessible N-(chlorosulfonyl)imidoyl chloride, CCl3C(Cl)=NSO2Cl (1), has been developed. Thus, a reaction of 1 as bielectrophilic 1,3-C–N–S reagent with benzylamines that act as 1,4-N–C–C-C binucleophiles, affords respective 1,2,4-benzothiadiazepine-1,1-dioxides. On the other hand, 1 reacts with alkenyl amines with the formation of respective N-alkenyl amidines undergoing Lewis acids initiated intramolecular cyclization to afford derivatives of 1,2,4-thiadiazines and 1,2,4-thiadiazocines bearing a halomethyl group able for further functionalization. The first examples of electrophilic heterocyclization of the chlorosulfonyl group onto an alkenyl or alkynyl group have been revealed.

Palladium-Catalyzed C-2 and C-3 Dual C-H Functionalization of Indoles: Synthesis of Fluorinated Isocryptolepine Analogues.

Here we report a protocol to synthesize diversiform fluorinated isocryptolepine analogues with potential biological activities in one step via directed C-2 and C-3 dual C-H functionalization of indoles. We also attempted to take into account fluorinated imidoyl chlorides as a novel kind of synthons in the directed C-H functionalization reactions. As a result, a variety of fluorinated isocryptolepine analogues were obtained in up to 96% yield. Moreover, we conducted control experiments to disclose the reaction mechanism.

α-Imino Iridium Carbenes from Imidoyl Sulfoxonium Ylides: Application in the One-Step Synthesis of Indoles.

Imidoyl sulfoxonium ylides are presented for the first time as potential precursors to generate α-imino metal-carbene intermediates and applied in direct C-H functionalization reactions catalyzed by [Ir(cod)Cl]2 (4 mol %) to provide 2-substituted indoles (up to 70% yield) in just one step. This class of sulfur ylide is successfully obtained from imidoyl chloride and dimethylsulfoxonium methylide (23 new examples in 45-85% yield) or by imino group formation from the corresponding β-keto sulfoxonium ylides and anilines in the presence of TiCl4 as a Lewis acid (9 examples in 33-94% yield).

3+2]‐Cycloadditions of N‐Cyano Sulfoximines with 1,3‐Dipoles

Involving the cyano group of N‐cyano sulfoximines in [3+2]‐cycloaddition reactions with 1,3‐dipoles provides practical routes for the construction of 5‐membered heterocycles bearing sulfoximinoyl moieties. An ytterbium‐catalyzed cycloaddition utilizing hydrazonoyl chlorides was developed, as well as a reaction involving imidoyl chlorides proceeding without the aid of a catalyst. Following these protocols, a range of sulfoximines with N‐1,2,4‐triazolyl and N‐1,2,4‐oxadiazolyl substituents was prepared.

Redox-Active α-Diimine Complexes of Early Transition Metals: From Bonding to Catalysis

Abstract It is an intrinsic nature that early transition metals favorably adopt their highest oxidation state with d0 configuration. We have been interested in early transition metal complexes bearing redox active α-diimine ligands for introducing redox processes at the metal center through reversible interconversion among possible coordination modes, i.e., a neutral 1,4-diaza-1,3-diene form A, a monoanionic form B, and dianionic ene-diamido forms, σ2-enediamido form C and σ2,π-enediamido form D. In this context, we continuously investigated synthesis of a series of α-diimine complexes of group 3, 5 and 6 metals by implementing two synthetic methodologies, (1) a salt-metathesis protocol by treating ligand-supported metal precursors with the alkali metal salts of α-diimines and (2) a salt-free protocol by applying organosilicon compounds, such as 3,6-di(trimethylsilyl)-1,4-cyclohexadiene (abbrev. Si-CHD) and 1,4-di(trimethylsilyl)-2-methyl-cyclohexa-2,4-diene (abbrev. Si-Me-CHD) together with 1,4-di(trimethylsilyl)-2,5-dimethyl-1,4-dihydropyrazine (abbrev. Si-Me2-DHP) and 1,4-di(trimethylsilyl)-2,3,5,6-tetramethyl-1,4-dihydropyrazine (abbrev. Si-Me4-DHP), for reducing homoleptic chlorides and imide chlorides of early transition metals in the presence of α-diimine ligands. This account thus summarizes the author’s achievements on bonding and reactivity of various α-diimine complexes of group 3, group 5, and group 6 metals as well as their catalytic performance.

Synthesis of Nitrogen-Containing Polyaromatics by Aza-Annulative π-Extension of Unfunctionalized Aromatics.

Nitrogen-containing polycyclic aromatic compounds (N-PACs) are an important class of compounds in materials science. Reported here is a new aza-annulative π-extension (aza-APEX) reaction that allows rapid access to a range of N-PACs in 11-84 % yields from readily available unfunctionalized aromatics and imidoyl chlorides. In the presence of silver hexafluorophosphate, arenes and imidoyl chlorides couple in a regioselective fashion. The follow-up oxidative treatment with p-chloranil affords structurally diverse N-PACs, which are very difficult to synthesize. DFT calculations reveal that the aza-APEX reaction proceeds through the formal [4+2] cycloaddition of an arene and an in situ generated diarylnitrilium salt, with sequential aromatizations having relatively low activation energies. Transformation of N-PACs into nitrogen-doped nanographenes and their photophysical properties are also described.

Synthesis of Nitrogen‐Containing Polyaromatics by Aza‐Annulative π‐Extension of Unfunctionalized Aromatics

AbstractNitrogen‐containing polycyclic aromatic compounds (N‐PACs) are an important class of compounds in materials science. Reported here is a new aza‐annulative π‐extension (aza‐APEX) reaction that allows rapid access to a range of N‐PACs in 11–84 % yields from readily available unfunctionalized aromatics and imidoyl chlorides. In the presence of silver hexafluorophosphate, arenes and imidoyl chlorides couple in a regioselective fashion. The follow‐up oxidative treatment with p‐chloranil affords structurally diverse N‐PACs, which are very difficult to synthesize. DFT calculations reveal that the aza‐APEX reaction proceeds through the formal [4+2] cycloaddition of an arene and an in situ generated diarylnitrilium salt, with sequential aromatizations having relatively low activation energies. Transformation of N‐PACs into nitrogen‐doped nanographenes and their photophysical properties are also described.

Direct access to vicinally functionalized and N-trifluoroacetylated (bicyclic)ketopiperazines using a readily affordable N-heterocyclic anhydride.

Functionalized 2-piperazinones play essential roles as conformationally-constrained peptidomimetics by mimicking inverse γ-turns in peptides. Here, we describe an efficient, scalable, stereoselective, modular, and chemoselective annulation protocol between a novel N-trifluoroacetyl anhydride and several reactive partners, including lactim ethers, imidoyl chlorides, aryl aldimines, and 1,3-azadienes, leading to vicinally functionalized (bicyclic) 2-piperazinones.

Phosphine-Catalyzed Divergent [4+3] Domino Annulations of CF3-Containing Imines with MBH Carbonates: Construction of Perfluoroalkylated Benzazepines.

Phosphine-catalyzed divergent [4+3] domino annulations of fluorinated imidoyl chlorides with MBH carbonates were developed. Two classes of perfluoroalkylated benzazepines were obtained in moderate to good yields via an interesting dearomatization/rearomatization sequence. Remarkably, the fluorinated imidoyl chlorides could be utilized for the first time as a new four-atom building block in phosphine catalysis. Moreover, the proposed mechanism is supported by capturing the intermediate.

Exploitation of Unconventional Electrophiles in Enantioselective Pd(0)-Catalyzed C-H Functionalizations.

Asymmetric metal-catalyzed C-H functionalization is a powerful strategy for the rapid generation of complex target molecules from simple precursors. While aryl (pseudo)halides have been used as electrophilic substrates in enantioselective Pd(0)-catalyzed syntheses of N-heterocycles, alternative partners for C-H functionalizations remain underexplored. Herein we describe the first application of ketene aminal phosphates as competent electrophiles in a Pd(0)-catalyzed desymmetrization. This transformation allowed the efficient synthesis of chiral isoindolines in a highly enantioselective fashion. Furthermore, intending to introduce sought-after perfluoroalkyl substituents, we explored intramolecular C-H functionalization of imidoyl chlorides resulting in the asymmetric preparation of previously inaccessible 1H-isoindoles. Tailored chiral monodentate ligands afforded high levels of enantioinduction in both transformations.

1-Imidoyl-1,2,3-benzotriazoles—Novel Reagents for the Synthesis of 1-Aryl-5-trifluoromethylimidazoles

1-Imidoylbenzotriazoles [N-aryl-1-(1H-benzotriazol-1-yl)-2,2,2-trifluoroethan-1-imines] reacted with tosylmethyl isocyanide according to van Leusen’s procedure to give difficultly accessible 1-aryl-4-(4-methylbenzenesulfonyl)-5-(trifluoromethyl)-1H-imidazoles in good yields (81–94%). The initial imidoylbenzotriazoles were conveniently synthesized by reaction of sodium benzotriazolide with the corresponding imidoyl chlorides in THF. The reactions were carried out with a wide series of imidoylbenzotriazoles containing various electron-donating and electron-withdrawing substituents in the N-aryl fragment.

A simple synthesis of trifluoromethylated pyridinium azomethine ylides by three-component reaction between pyridines, phenacyl bromides, and N-aryltrifluoroacetimidoyl chlorides

A novel synthesis of trifluoromethylated pyridinium azomethine ylides by three-component reaction between pyridines, phenacyl bromides, and trifluoromethylated imidoyl chlorides in acetonitrile as solvent at room temperature without any catalyst is described. The FT-IR, 1H, 13C, 19F NMR spectral and elemental analysis confirm the structures of products. The synthesized azomethine ylides are easily purified by washing with diethyl ether and are stable even at high temperature. Heating of these ylides in refluxing acetonitrile, ethanol, or DMSO did not result in the intramolecular cyclization to imidazopyridine derivatives and only starting ylides were isolated.

Synthesis and antimicrobial evaluation of new glucosylimino thiazole derivatives

p-Sulphonic-N-propionyl aniline 3 was produced from sulphanilic acid with propionic acid under reflux for 2 h, then the compound 3 reacted with thionyl chloride and the corresponding imidoyl chloride 4 was obtained. When imidoyl chloride 4 reacted with potassium isothiocyanate and aniline, the corresponding thiourea derivatives 6 was produced. Compound 6 was reacted with tricyanovinylamine to produce the thiazole derivative 7 after cyclization. The microwave-assisted condensation of 2,3,4.6,-tetra-O-acetyl-β-D-glucopyranosylisothiocynate 8 with thiazole derivative 7 afforded the thiourea derivatives 9. Compound 10 a, b has been synthesized by reacting thiourea derivatives 9 with chloroacetone. The prepared compounds were screened for antibacterial properties against Staphylococcus aureus and Escherichia coli, and antifungal activity against Candida sp. The structure assignments of the new synthesized compounds are based on spectroscopic data.