Reactions of N-polyfluorophenylcarbonimidoyl dichlorides with primary and secondary amines. Kinetics and mechanism. Synthesis of polyfluorinated carbodiimides, chloroformamidines, guamidines and benzimidazoles.

The reaction of N-polyfluorophenylcarbonimidoyl dichlorides with primary and secondary aliphatic and aromatic amines have been studied. With primary aliphatic amines, the reactions led to carbodiimides or guanidines, depending on the amount of amine. The carbodiimides obtained reacted with amines to form guanidines. The reactions with primary aromatic amines produced only triarylguanidines. N-Pentafluorophenyllcarbonimidoyl dichloride (I) reacted with tetrafluoro-o-phenylene diamine to give 2-pentafluoroanilino-4,5,6,7-tetrafluorobenzimidazole. Polyfluorinated benzimidazole derivatives were also produced by the thermolysis of polyfluorinated triarylguanidines. Heating of N¹,N²,N³-tris(pentafluorophenyl)guanidine with K₂CO₃ in dimethylformamide led to 1,2,3,4,7,8,9,10-octafluoro-5-pentafluorophenyl-5H-benzimidazol[1,2-a]benzimidazole. N-Polyfluorophenylcarbonimidoyl dichlorides reacted with various secondary amines already at room temperature giving N-polyfluorophenylchloroformamidines in high yields. Elevated temperature and prolonged reaction time led to formation of N-polyfluorophenylguanidines. Kinetics and mechanism of the reactions of N-polyfluorophenylcarbonimidoyl dichlorides with primary and secondary amines in acetonitrile at 25°C have been studied. The reactions have been found to proceed by a bimolecular nucleophilic addition-elimination mechanism via a tetrahedral intermediate. Possible reasons of formation of different products in the above transformation are discussed in terms of this mechanism.     

Organogermanium polymers prepared from s‐indacene and carbodiimide compounds

The synthesis of bis‐organogermanium compounds including s‐indacene structure was described and showed the formation of one type of trans isomer characterized by spectroscopic methods. In the same way, the digermyl‐s‐indacene dichlorides were prepared and structural characterizations confirmed the unique formation of trans isomers. These digermyl‐s‐indacene dichlorides were used as monomers in a polymerization reaction in order to prepare poly(germyl‐s‐indacenes) and poly(germyl‐s‐indacene carbodiimides). However, only the products obtained from tetraalkyl‐s‐indacene reached high molecular weight, probably due to a minor steric hindrance compared to the hexaalkyl‐s‐indacene. Thermal degradation only starts from 250°C for poly(germyl‐s‐indacene carbodiimides) and from 350°C for poly(germyl‐s‐indacenes). The structures of the first digermyl‐s‐indacene dichlorides were determined by X‐ray analysis, confirming that the chlorogermyl groups are located in trans positions. Copyright © 2012 John Wiley & Sons, Ltd.     

Catalytic C=N bond metathesis of carbodiimides by group 4 and 5 imido complexes supported by guanidinate ligands

A family of guanidinate-supported imido metal complexes are novel, effective catalysts for C=N metathesis of alkyl and aryl carbodiimides and evidence suggests that this reaction proceeds via a sequential addition/elimination pathway.     

Three-component, one-pot sequential synthesis of N-aryl, N'-alkyl barbiturates

[reaction: see text] Condensation between N-alkyl, N'-aryl carbodiimides and malonic acid monoesters leads to a high-yield formation of N-acyl urea derivatives that could be cyclized to C-monosubstituted barbiturates by addition of a suitable base in a one-pot sequential fashion. In the presence of an electrophile, the last step gives rise to a one-pot, three-component sequential synthesis of fully substituted barbiturates.     

Three-component sequential synthesis of N,N′-disubstituted 5-arylidenedihydropyrimidine-2,4-dione

A three-component sequential process consisting in (1) in situ formation of carbodiimides by Staudinger reaction, (2) reaction with 2-(bromomethyl)-3-aryl-2-propenoic acids, and (3) final cyclization of the resulting N-acylurea intermediates in order to obtain the synthesis of an array of N,N′-disubstituted 5-arylidenedihydropyrimidine-2,4-dione under mild conditions is presented.     

Iodine-mediated direct synthesis of multifunctional 2-aminobenzimidazoles from N-substituted o-diaminoarenes and isothiocyanates

Multifunctional 2-aminobenzimidazoles were directly synthesized through sequential addition of N-substituted o-diaminoarenes to isothiocyanates, formation of carbodiimides via I₂-mediated oxidative desulfurization, and intramolecular cycloaddition. This efficient and eco-friendly synthetic process provides a facile access to diverse 2-aminobenzimidazole derivatives from readily accessible substrates under mild reaction conditions in a scalable fashion.     

Fünf- und sechsgliedrige cyclische Phosphonsäure-diamide und-thioester-amide sowie Spirobi[oxazaphosphole]

Five- and Six-Membered Cyclic Phosphonic Diamides, Thioester-amides and Spirobi[oxazaphospholes] By reaction of the 1,2-diaminobenzene derivatives 1a–d with the phosphonoyl dichlorides 2a–g , the 1,3-dihydro-1,3,2-benzodiazaphosphol-2-ones 4a–q are obtained. The phosponoyl dichlorides 2a–e, 2g , and 2h yield with naphthalene-1,8-diamines ( 5 ) the diazaphosphinones 6a–g under similar reaction conditions. The thiazaphosphole oxides 9a–d are accessible by reaction of the phosphonoyl dichlorides 2a–d with 2-aminobenzenethiol ( 7 ). Unexpectedly, the reaction of the dichlorides 2a and 2b with 2-aminophenol ( 10 ) led to the spirobi[oxazaphospholes] 13a and 13b , respectively.     

Copper-catalyzed domino reaction of carbodiimides and benzoic acid derivatives for the synthesis of quinazolinediones

Quinazolinediones were obtained from 2-iodobenzoic acids and carbodiimide derivatives under mild reaction conditions via a copper-catalyzed domino reaction. The absence of an external base was essential to avoid the generation of amide by-products. Both alkyl- and aryl-substituted carbodiimides gave the corresponding quinazolinediones. However, the use of aryl-substituted carbodiimides resulted in low yields due to an undesired elimination process.     

A protocol to 2-aminobenzimidazoles via copper-catalyzed cascade addition and cyclization of o-haloanilines and carbodiimides

An efficient strategy for the synthesis of a variety of 2-animobenzimidazole derivatives has been developed. The reaction proceeded from o-haloanilines and carbodiimides via copper(I)-catalyzed domino reaction in the presence of tert-butoxide to afford the corresponding 2-animobenzimidazole derivatives in good to excellent yields. o-Haloanilines could be o-iodoaniline, o-bromoaniline, and o-chloroaniline derivatives. Carbodiimides could be symmetrical and unsymmetrical substrates with aryl or alkyl substituents. The reaction exhibited a good regioselectivity when unsymmetrical carbodiimides were employed.     

Novel rhodium-catalyzed reaction of thiazolidine derivatives with carbodiimides

A new, simple, and regioselective synthesis of thiazolidinimine derivatives based on the rhodium-catalyzed reaction of readily available thiazolidines with carbodiimides is described. This methodology provides direct access to a large variety of thiazolidinimine derivatives, possibly via a novel regiospecific insertion of carbodiimides into one of two ring carbon-nitrogen bonds, as well as a metal-catalyzed imine elimination process.     

Preparation of carbodiimides by the reaction of thioureas with diethyl azodicarboxylate

A new synthesis of disubstituted carbodiimides from N.N′-disubstituted thioureas, diethyl azodicarboxylate and triphenyl phosphine has been achieved. The intermediates of the reaction have been isolated and found to be 1:1 adducts of the thioureas and diethyl azodicarboxylate, N¹,N²-disubstituted—S—(N³,N⁴-biscarboethoxy)hydrazinoisothioureas which, on treatment with triphenyl phosphine at room temperature, afford the corresponding carbodiimides. Alternatively, the intermediates on heating under reflux in benzene or toluene, decompose to the carbodiimides, diethyl hydrazodicarboxylate and sulphur.     

The use of selenium(IV) chloride for the preparation of diarylselenium dichlorides

Two new synthetic routes for the preparation of diarylselenium dichlorides are reported both of which use selenium(IV) chloride as a starting meterial. In the first method, bis(p-methóxyphenyl) and bis(p-ethoxyphenyl)-selenium dichlorides are prepared by the reaction of SeCl₄ with anisole and phenetole respectively. In the second, diphenylselenium dichloride is prepared by the reaction of SeCl₄ with tetraphenyllead, a reaction in which the lead—carbon bond is cleaved.The far infrared and Raman spectra of the diarylselenium dichlorides are reported.     

Bis(disilanyl)- and bis(trisilanyl)carbodiimides

Conclusions The reaction of chlorodi- and trisilanes with silver cyanamide gave bis(disilanyl)carbodiimides and bis(trisilanyl)carbodiimides in high yield.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2824–2825, December, 1985.     

Synthesis of symmetrically and unsymmetrically substituted S,S-dialkyl phosphonodithioates

Herein, we report the synthesis of a range of S,S-dialkyl phosphonodithioates. Symmetrically substituted analogues were readily prepared from the corresponding phosphonic dichlorides in good to moderate yields, while unsymmetrically substituted variants were obtained by a sequential alkylation-deprotection-alkylation strategy.     

Herstellung von substituierten 2-Aminooxazol-4-carbonitrilen

Preparation of Substituted 2-Aminooxazole-4-carbonitriles During our synthetic programme to convert 4-isoxazolylthioureas 3 into the corresponding carbodiimides 5 , a side reaction leading to the hitherto unknown 2-aminooxazole-4-carbonitriles 6 was observed. By selecting appropriate reaction conditions, it was possible to improve the yields of the carbodiimides 5 as well as of the novel oxazole-carbonitriles 6 at will, thus allowing the synthesis of 6 to be conducted in very good yields. To overcome the difficulty of isolating unstable carbodiimides, the synthesis of 6 is best carried out in a one-pot procedure. A limited mechanistic study showed that the formation of 6 proceeds via 5 as the only intermediate. The stability of the N?C?N bonds against base attack (depending strongly on both sterical hindrance and electronic-density factors) forms the only limitation of this new synthetic pathway to oxazole-4-carbonitriles.     

Multicomponent, one-pot sequential synthesis of 1,3,5- and 1,3,5,5-substituted barbiturates

Carbodiimides and malonic acid monoethylesters readily react to afford N-acylurea derivatives that could be cyclized in situ by addition of a suitable base. This process represents a general and straightforward one-pot sequential synthesis of 1,3,5-trisubstituted barbiturates in very mild conditions (organic solvent/2 N NaOH aqueous solution, 20 degrees C). Performing the reaction in the presence of an electrophile resulted in the formation of fully substituted (namely, 1,3,5,5-tetrasubstituted) barbiturates through a three-component one-pot sequential process. The latter, however, occurred only with highly reactive electrophiles, such as benzyl and, in some instances, allyl halides. In order to expand the scope of the process, we sought to develop a general method for the C-alkylation of 1,3,5-trisubstituted barbiturates. We found that C-alkylation occurred upon treatment of 1,3,5-trisubstituted barbiturates with an alkyl halide in CH3CN at 120 degrees C in the presence of anhydrous K2CO3 affording the target 1,3,5,5-tetrasubstituted barbiturates in good yields. The multicomponent process was accomplished by combining the three steps in a one-pot sequential fashion, i.e., the condensation of carbodiimides with malonic acid monoethylesters, the cyclization of the resulting N-acylureas, and the C-alkylation of the resulting 1,3,5-substituted barbiturates. A detailed study of the influence of the structure of the reactants on the reaction outcome and mechanism is presented. By selective N'-deprotection of 1,3,5,5-tetrasubstituted barbiturates, the corresponding 1,5,5-trisubstituted barbiturates were also prepared.     

Study on the Reaction of Tricovalent Chlorophosphines with Aldehydes Containing Withdrawing Electron Groups

α-Polychloroalkyl phosphoric dichlorides and their derivatives 2,3,4 has insecticidal activity^1-4 and may be used as an intermediate to make other insecticides by reaction with alcohol, phenol, thiophenol or mercaptan. They can be prepared by various conventional methods of preparing phosphorus thioesters. Here we wish to report the addition reaction of tricovalent chlorophosphines with aldehydes containing withdrawing electron groups and its application in preparing of polychloroalkyl phosphorus dichlorides and their derivatives. The process can be represented by the following equation.     

Synthesis of N-cyano monoaza crown ethers

N-Cyano monoaza crown ethers were prepared by the reaction of cyanamide with oligoethylene glycol dichlorides or ditosylates in the NaH/DMSO reaction system and led to the derivatives.     

Synthesis and reactions of organometallic carbodiimides and isocyanates

Conclusions A convenient laboratory method has been proposed for the preparation of organometallic tin and germanium carbodiimides in excellent yields and satisfactory purities.Organotin carbodiimides react with dicarboxylic acid anhydrides to give addition products, namely, organotin derivatives of N-substituted dicarboxylic acid monocyanamides. The corresponding reaction of tin and germanium isocyanates lead to the formation of N-tributylstannyl(germyl)imides of dicarboxylic acids, and CO₂.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 859–865, April, 1988.     

A Catalytic Route to Pyrrole Derivatives via Copper‐catalyzed Multicomponent Reaction

A novel approach for the synthesis of pyrrole derivatives has been reported. The reactions starting from terminal alkynes, carbodiimides, and malononitrile using CuI, DBU, and TBPAc in anhydrous MeCN afforded the functionalized pyrroles in acceptable yields. Alkyl‐, aryl‐, and heteroaromatic terminal alkynes were tolerated. Carbodiimides could be symmetrical and unsymmetrical substrates with aryl or alkyl substituents. The reaction exhibited a good regioselectivity when unsymmetrical carbodiimides were employed.