Imidoyl Chlorides Research Articles

SYNTHESIS OF NEW (3-FLUOROIMIDAZO[1,2- a ]PYRIDIN-2-YL)-PHOSPHONATES

New (3-fluoroimidazo[1,2-a]pyridin-2-yl)phosphonates were synthesized by a tandem reaction of imidoyl chlorides with two equivalents of triethyl phosphite. Authors: A. Yu. Aksinenko, T. V. Goreva, T. A. Epishina, and V. B. Sokolov English Translation in Chemistry of Heterocyclic Compounds, 2013, 49 (3), pp 417-420 http://link.springer.com/article/10.1007/s10593-013-1262-9

Nef-isocyanide–Perkow synthesis of new polarized olefins containing 2-dicyanomethylene-2,3-dihydrothiazole and 2-dicyanomethylene-1,3-dithiole moieties

Imidoyl chlorides (generated from isocyanides and acyl chlorides) reacts with triisopropyl phosphite, in a Perkow-type reaction, to produce 1-alkoxycarbonyl-2-(alkylimino)vinyl diisopropyl phosphate, which undergo a smooth reaction with bidentate nucleophilic intermediates obtained from the reaction between malononitrile and heterocumulenes, such as arylisothiocyanates or carbon disulfide to produce polarized olefins containing 2-dicyanomethylene-2,3-dihydrothiazole and 2-dicyanomethylene-1,3-dithiole moieties.

Investigation of facet effects on the catalytic activity of Cu2O nanocrystals for efficient regioselective synthesis of 3,5-disubstituted isoxazoles

Cubic, octahedral, and rhombic dodecahedral Cu2O nanocrystals bound by respectively {100}, {111}, and {110} facets were successfully employed to catalyze the [3 + 2] cycloaddition reaction for the regioselective synthesis of 3,5-disubstituted isoxazoles. Surfactant-free nanocrystals having the same total surface area were used for the catalysis. Strongly facet-dependent organocatalytic activity has been observed. Rhombic dodecahedra with fully exposed surface copper atoms on the (110) planes are the most efficient catalysts, followed by octahedra and the least active nanocubes. The particles are also recyclable catalysts. Cu2O rhombic dodecahedra were also used for the syntheses of 3,5-disubstituted isoxazoles from a wide variety of aromatic imidoyl chlorides and terminal alkynes in ethanol at 50 °C with excellent yields. Furthermore, a one-pot multi-component synthetic approach was demonstrated to form isoxazoles directly from readily available aldehyde precursors. This work clearly shows that precise facet engineering of Cu2O crystals can lead to significantly improved organocatalytic efficiency.

ChemInform Abstract: α‐Amination of Keto‐nitrones via Multihetero‐Cope Rearrangement Employing an Imidoyl Chloride Reagent.

AbstractThe condensation of nitronates (I) with imidoyl chloride (II) followed by a [3,3]‐rearrangement affords desired carbamates (III).

Palladium-Catalyzed Synthesis of Benzimidazoles and Quinazolinones from Common Precursors

N-(o-Halophenyl)imidoyl chlorides and the corresponding imidates are easily prepared and can be utilized as complementary precursors for the synthesis of important heterocycles. The synthesis of N-substituted benzimidazoles was possible from the palladium-catalyzed reaction of both classes of substrate with a variety of N-nucleophiles. The use of the imidate precursor for the synthesis of N-substituted quinazolinones by incorporation of a palladium-catalyzed aminocarbonylation reaction has also been demonstrated. Both processes tolerate a wide range of functional groups.

ChemInform Abstract: Copper‐Catalyzed Synthesis of 1,2‐Disubstituted Benzimidazoles from Imidoyl Chlorides.

Abstract A strategy for the synthesis of 1,2-disubstituted benzimidazoles has been developed and a variety of 1,2-disubstituted benzimidazoles were obtained from imidoyl chlorides and o -haloanilines via copper(I)-catalyzed reaction in moderate yields.

ChemInform Abstract: Synthesis of Isoxazole Triflones.

AbstractThe first practical synthesis of trifluoromethylsulfonyl‐substituted isoxazoles (III), (V) and (VII) is presented, involving base‐mediated cyclization of α‐triflyl ketones (I) and (VI) with aryl imidoyl chlorides (II) and (IV).

Glycosyl N-Tosyl Benzimidate as a New Building Block for Chemical Glycosylation

Seven novel glycosyl <i>N</i>-tosyl benzimidates were prepared by the reactions of the corresponding hemiacetals with imidoyl chloride in 55–88% yields, which were smoothly converted to glycosides, upon treatment with alcohols and catalytic TMSOTf, in 57–99% yields.

ChemInform Abstract: New Preparation Method for Vilsmeier Reagent and Related Imidoyl Chlorides.

AbstractA novel method for the synthesis of Vilsmeier reagent (II) and related imidoyl chlorides uses OPC as chlorinating agent.

Chemistry of polyhalogenated nitrobutadienes, 10: Synthesis of highly functionalized heterocycles with a rigid 6-amino-3-azabicyclo[3.1.0]hexane moiety

The nitropolychlorobutadienes 3, 4 are valuable building blocks for various amination and successive heterocyclization products. Nucleophilic substitution reactions of the partially protected, bioactive amines 1, 2 with either vinyl, imidoyl or carbonyl chlorides result in the formation of the enamines 11, 12, 13, 16, 25, the amidine 6, and the amides 20, 21, respectively. In the following, cyclization to the highly functionalized pyrazoles 27, 28, pyrimidine 26 and pyridopyrimidine 24 succeeded. Deprotection of 21, 12 and 28 proved to be only partially feasible.

Copper-catalyzed synthesis of 1,2-disubstituted benzimidazoles from imidoyl chlorides

A strategy for the synthesis of 1,2-disubstituted benzimidazoles has been developed and a variety of 1,2-disubstituted benzimidazoles were obtained from imidoyl chlorides and o-haloanilines via copper(I)-catalyzed reaction in moderate yields.

Synthesis of Isoxazole Triflones

AbstractThe first practical synthesis of isoxazole triflones 3 (4‐trifluoromethanesulfonylisoxazoles, 4‐triflylisoxazoles) has been achieved by an operationally simple procedure consisting of the reaction between readily available α‐triflyl ketones 4 and imidoyl chlorides 5 in the presence of triethylamine. The present method provides the biologically attractive isoxazoles featuring a triflyl group at the 4‐position with a wide substrate scope in good to high yield in all cases.

Efficient synthesis of pyrimido[5,4‐c]pyridazines and of thiino[2,3‐d]pyrimidines based on an aza‐wittig reaction/heterocyclization strategy

AbstractA simple one‐pot and efficient method is described for the synthesis of pyrimido[5,4‐c]pyridazines 5 and of thiino[2,3‐d] pyrimidines 15 by a domino process involving an aza‐Wittig reaction/heterocyclization. The iminophosphorane 2 reacted with phenylisocyanate, followed by heterocyclization on addition of amines to give the corresponding guanidine intermediates 4. The guanidine intermediates were cyclized in the presence of catalytic amount of sodium ethoxide to pyrimido[5,4‐c]pyridazines 5. Similarly, iminophosphorane 12 reacted with phenylisocyanate and amines to give thiino[2,3‐d]pyrimidines 15 in moderate yields. Furthermore, pyridazino[4,3‐d]oxazines 10 and thiino[2,3‐d]oxazines 19 were synthesized by the intremolecular aza‐Wittig reaction of phosphazenes 2 and 12, respectively, with acid chlorides followed by heterocylization via imidoyl chloride intermediates. J. Heterocyclic Chem., (2012).

α-Amination of keto-nitrones via Multihetero-Cope rearrangement employing an imidoyl chloride reagent

α-Aminations of ketone-derived nitrones have been developed via [3,3]-rearrangement of the intermediates generated upon condensation with imidoyl chlorides. Careful reagent selection provides synthetically attractive amino protecting groups. The enediamide or α'-carbamoyl enamide products can be hydrolyzed to the desired carbonyl, or exposed to electrophiles for further α-functionalization.

Conformational analysis via calculations and NMR spectroscopy for isomers of the mono(imino)pyridine ligand, 2-{(2,6-Me2-C6H3)NC(i-Pr)}C5H4N

Sterically hindered (imino)pyridine 2-{(2,6-Me2-C6H3)NC(i-Pr)}C5H4N (1) was synthesized via addition of isolated imidoyl chloride to an in situ lithiated pyridine. Room temperature 1-D and 2-D NMR spectroscopy reveals two rapidly equilibrating isomers in solution. Interconversion of these two isomers was verified by 2D-EXSY NMR spectroscopy. Calculations at the B3LYP and MP2 levels of theory reveal four relevant isomers, with two atropisomers of E geometry (1-EA and 1-EB) and two atropisomers of Z geometry (1-ZA and 1-ZB). A simple carbon–carbon bond rotation to alter the orientation of the isopropyl group provides a fifth, related conformer, 1-ZB′, that is the most stable species at the MP2 level. The transition states for E/Z isomerization and the isomerization pathways between atropisomers have been characterized. Comparison of experimental and ab initio NMR chemical shifts in combination with NOE analysis suggests that isomers 1-EB and 1-ZB/1-ZB′ are the dominant species in our solution phase NMR studies. Our understanding of the isomerization behavior of 1 will help inform the future design of readily complexed, sterically hindered mono(imine) and bis(imine) ligands.

New preparation method for Vilsmeier reagent and related imidoyl chlorides

An environmentally benign and inexpensive preparation method is described of some imidoyl chlorides, including the Vilsmeier reagent (VR), by using phthaloyl dichloride. Synthetic applications were demonstrated using the isolated VR or VR prepared in situ for the transformation of acids to acid chlorides, alcohols to chlorides, and the formylation of dimethylaminobenzene.

Implanting Nitrogen into Hydrocarbon Molecules through CH and CC Bond Cleavages: A Direct Approach to Tetrazoles

The development of novel methods for the preparation of tetrazoles is of long-standing interest and a challenge for organic chemists because of the importance of these compounds in chemistry and biology. In particular, 1,5-disubstituted tetrazoles are very useful compounds in medicinal chemistry and important synthetic intermediates. In the past several decades, some general strategies for the synthesis of 1,5-disubstituted tetrazoles from functionalized starting materials have been developed (Scheme 1). These methods include: a) the reactions of ketones or oximes with sodium azide and hydrogen azides, b) the reactions of amides with sodium azides in the presence of phosphorus(V) chloride or triflic anhydride and the reactions of amidrazones with dinitrogen tetroxide or nitrous acid, c) the reactions of imidoyl chlorides or imidoylbenzotriazoles with sodium azides and, d) the reactions of nitriles with alkyl azides. These developed methods significantly improved the synthesis of tetrazoles, but these approaches have some limitations, such as the use of protic acid catalysts, tedious workups, and the use of functionalized starting materials, hence encouraging scientists to discover new strategies. The direct transformation of hydrocarbon molecules by transition-metal-catalyzed selective C H and C C bond activation (cleavage) has attracted considerable attention, owing not only to its fundamental scientific appeal but also to its potential utility in organic synthesis. A direct approach to tetrazoles through C H and C C bond cleavages of simple hydrocarbon molecules is still an extremely attractive yet challenging goal. Herein, we demonstrate a novel and efficient Cu-promoted implanting of nitrogen into simple hydrocarbon molecules to construct 1, 5-disubstituted tetrazoles through C H and C C bond cleavages, and C N bond formation under mild and neutral reaction conditions (Scheme 1e). Azide has been widely used as a useful aminating reagent in organic synthesis. The application of azides for the direct synthesis of aryl nitriles and alkenyl nitriles through C H bond cleavage has been recently reported. Recent achievements on the functionalization of C H and C C bonds encouraged us to try the direct synthesis of

A novel one-pot synthesis of α-keto-1,3,4-oxadiazole derivatives based on isocyanide-Nef reaction

Various α-keto-1,3,4-oxadiazole derivatives were synthesized through a sequential intermolecular dehydrochlorination/intramolecular aza-Wittig reaction of carboxylic acids and imidoyl chloride intermediates, which were generated by isocyanide-Nef reaction of acyl chlorides and ( N-isocyanimine) triphenylphosphorane ( 1) in CH 2Cl 2 at room temperature.

Acyclic N-phenylsubstituted polyimides based on imidoyl chlorides and dicarboxylic acids

Acyclic polyimides are prepared for the first time through the interaction of imidoyl chlorides and dicarboxylic acids. This transformation passes through the formation of polycarboxyimidates, which, depending on the temperature of reaction, rearrange in situ via the Mumm-Hess mechanism or during subsequent heating to yield the target product. The polymers thus prepared show high solubility and thermal stability (380–450°C).

ChemInform Abstract: Synthesis of 2‐Azaanthracenes via a Sequential Sonogashira Coupling/Alkynyl Imine—Allenyl Imine Isomerization/Aza‐Diels—Alder/Elimination—Aromatization Reaction.

AbstractThe reaction of various 1,6‐diynes with imidoyl chlorides, bearing substituted benzyl groups at the nitrogen, leads to the target 2‐azaanthracenes.