Microwave-assisted synthesis of N,N-bis-(2-pyridylmethyl)amine derivatives. Useful ligands in coordination chemistry

Microwave-assisted synthesis of the ligands N,N-bis-(2-pyridylmethyl)amine (BMPA), N-(methylpropanoate)-N,N-bis-(2-pyridylmethyl)amine (MPBMPA), N-(propanamide)-N,N-bis-(2-pyridylmethyl)amine (PABMPA), PNBMPA (N-(3-propionitrile)-N,N-bis-(2-pyridylmethyl)amine), N-(3-aminopropyl)-N,N-bis-(2-pyridylmethyl)amine (APBMPA), and lithium N-(proponoate)-N,N-bis-(2-pyridylmethyl)amine (LiPBMPA) are reported. High yields and short reaction time were obtained for condensation and Michael addition.     

Synthesis and reactions of N-acetyl- and N-(2-chloroacetyl)-N-[(2E)-1-methylbut-2-en-1-yl]-2-iodoanilines

The reaction of N-(1-methylbut-2-en-1-yl)-2-iodaniline with Ac₂O or ClCH₂C(O)Cl results in a mixture of syn- and anti-atropisomers of N-acetyl- and N-chloroacetyl-N-(1-methylbut-2-en-1-yl)-2-iodaniline in a ratio of 1:1. Ozonolysis of the latter followed by reduction with dimethyl sulfide in CH₂Cl₂ gives rise to the atropisomers mixture of 2-[N-(chloroacetyl)-N-(2-iodophenyl)]aminopropanal in a ratio of 1:3. When heated in boiling benzene, the mixture of atropoisomeric aldehydes reacts with triphenylphosphine to afford a mixture of 2-[(N-acetyl)-N-(2-iodophenyl)]aminopropanal atropisomers in 1:3 ratio.     

Synthesis, structure, and heck cyclization of the syn- and anti-atropisomers of N-acyl-N-(4-methyl-3,6-dihydro-2H-pyran-3-yl)-2-iodo-4,6-dimethylaniline

The reaction of 2-iodo-2,4-dimethylaniline with 3,4-dibromo-4-methyltetrahydro-2H-pyran, followed by treatment with acetyl bromide or 4-nitrobenzoyl chloride, gave syn- and anti-atropisomers of N-(2-iodo-4,6-dimethylphenyl)-N-(4-methyl-3,6-dihydro-2H-pyran-3-yl)acetamide and N-(2-iodo-4,6-dimethylphenyl)-N-(4-methyl-3,6-dihydro-2H-pyran-3-yl)-4-nitrobenzamide. Heating of the acetamide derivative with palladium(II) acetate in the presence of copper(II) acetate and N,N,N′,N′-tetramethylethane-1,2-diamine resulted in heterocyclization to N-acetyl-4a,6,8-trimethyl-1,4a,9,9a-tetrahydropyrano[3,4-b]indole.     

A mild and efficient cyanosilylation of ketones catalyzed by a Lewis acid-Lewis base bifunctional catalyst

A new family of bifunctional catalysts (N-oxides-Ti(OⁱPr)₄ (2:1)) containing a Lewis acid and a Lewis base was developed and applied to the catalytic cyanosilylation of ketones. Utilizing rac((1R,2S) and (1S,2R))-1-(2′-pyridylmethyl)-2-diphenylhydroxymethylpyrrolidine N-oxide-titanium (2:1) complex and N-benzyl-diethanolamine N-oxide-titanium (2:1) complex as catalysts, the cyanosilylation products were obtained in 42-97% yield. Based on experimental phenomena and kinetic studies, a catalytic cycle was proposed to explain the remarkable activities of these catalysts. Investigations indicated that rac((1R,2S) and (1S,2R))-1-(2′-pyridylmethyl)-2-diphenylhydroxymethylpyrrolidine N-oxide-titanium (2:1) complex and N-benzyl-diethanolamine N-oxide-titanium (2:1) complex should promote the reaction via a dual activation of the ketone by the titanium and TMSCN by the N-oxide.     

Antibacterial activity of N-quaternary chitosan derivatives: Synthesis, characterization and structure activity relationship (SAR) investigations

Quaternary N-(2-(N,N,N-tri-alkyl ammoniumyl and 2-pyridiniumyl) acetyl) derivatives of chitosan polymer, chitooligomer, and glucosamine (monomer) were synthesized for the purpose of investigating the structure activity relationship (SAR) for the antibacterial effect. Novel methods were used in the synthesis. The final chitosan and chitooligomer derivatives could thus be obtained in two steps without prior protection of the hydroxyl groups. However, in order to obtain chitosan derivatives with the bulky N,N-dimethyl-N-dodecyl- and N,N-dimethyl-N-butyl side chains three steps were needed, starting from 3,6-O-di-tert-butyldimethylsilyl chitosan (3,6-O-di-TBDMS chitosan) as the key intermediate. The quaternary ammoniumyl acetyl derivatives of glucosamine were synthesized from glucosamine or tetra-O-acetylglucosamine. N,N,N-trimethyl chitosan (TMC) was used as reference compound for investigation of antibacterial activity. Clinical Laboratory Standard Institute (CLSI) protocols were used to determine MIC and MLC for activity against clinically important Gram-positive strains Staphylococcus aureus (ATCC 25923), and S. aureus (MRSA) (ATCC 43300), and Gram-negative strains of Escherichia coli (ATCC 25922), P. aeriginosa (ATCC 27853) and Enterococcus facialis (ATCC 29212). The MIC values for the compounds ranged from 8 to ?8192 mg/L. In general the N-(2-(N,N-dimethyl-N-dodecyl ammoniumyl) acetyl) derivatives of chitooligomer and glucosamine monomer were more active against bacteria than derivatives with shorter alkyl chains. In contrast the N-(2-(N,N-dimethyl-N-dodecyl ammoniumyl) acetyl) derivatives of chitosan were less active than derivatives with N-(2-N,N,N-trimetylammoniumyl) acetyl or N-(2-(N-pyridiniumyl) acetyl) quaternary moiety. N,N,N-trimethyl chitosan (TMC) was the most active compound in this study.     

Two-photon induced fluorescence of novel dyes

Three novel compounds, trans-2-[p-(N-ethyl-N-(hydroxyethyl)amino)styryl]-N-methylbenzothiazolium iodide (1), trans-2-[p-(N-ethyl-N-(hydroxyethyl)amino)styryl]-1′,3′,3′-trimethylindolium iodide (2), and trans-2-[p-(N,N-dimethylamino)styryl]-1′,3′,3′-trimethylindolium iodide (3), were synthesized and their two-photon induced fluorescence behavior was studied. Under excitation by 1064 nm laser irradiation, the solutions of these compounds exhibit two-photon induced fluorescence with λ_max at 639, 666 and 665 nm for 1, 2 and 3 respectively.     

Cyclization of trifluoro-<Emphasis Type="Italic">N</Emphasis>-(prop-2-yn-1-yl)methanesulfonamides to <Emphasis Type="Italic">N</Emphasis>-(hydroxymethyl)-1,2,3-triazoles

Three-component heterocyclizations of trifluoro-N-(prop-2-yn-1-yl)methanesulfonamide, trifluoro-N-pheny-N-(prop-2-yn-1-yl)methanesulfonamide, and trifluoro-N,N-di(prop-2-yn-1-yl)methanesulfonamide with formaldehyde and sodium azide afforded N-{[2-(hydroxymethyl)-2H-1,2,3-triazol-4-yl]methyl}-, N-{[2-(hydroxymethyl)-2H-1,2,3-triazol-4-yl]methyl}-N-phenyl-, and N,N-bis{[2-(hydroxymethyl)-2H-1,2,3-triazol-4-yl]methyl}trifluoromethanesulfonamides as the major products together with minor 1-(hydroxymethyl)-1H-1,2,3-triazole isomers.     

Synthesis of novel chiral NiII complexes of dehydroalanine Schiff bases and their reactivity in asymmetric nucleophilic addition reactions. Novel synthesis of (S)-2-carboxypiperazine

New chiral Ni^II complexes of Schiff bases of dehydroalanine with modified chiral auxiliaries (S)-2-N-[N′-(3,4-dichlorobenzyl)prolyl]aminobenzophenone (3,4-DCBPB), (S)-2-N-[N′-(3,4-dimethylbenzyl)prolyl]aminobenzophenone (3,4-DMBPB), (S)-2-N-[N′-(2-chlorobenzyl)prolyl]aminobenzophenone (2-CBPB), and (S)-2-N-[N′-(2-fluorobenzyl)prolyl]-aminobenzophenone (2-FBPB) have been synthesized. Asymmetric Michael addition reactions of primary and secondary amines and thiols to the dehydroalanine moieties of the complexes were studied. (S)-2-FBPB was found to be the best chiral auxiliary in terms of both selectivity of the reactions (de ～92–96%) and reactivity of the complexes. A novel synthetic route toward (S)-2-carboxypiperazine was developed based on the auxiliary.     

Reaction of N-methylsulfonyl-and N-(p-tolylsulfonyl)-2-(cyclopent-1-en-1-yl)anilines with bromine in the presence of potassium thiocyanate and in methanol

The reactions of N-methylsulfonyl-and N-(p-tolylsulfonyl)-2-(cyclopent-1-en-1-yl)-6-methylaniline with molecular bromine in the presence of potassium thiocyanate gave N-methylsulfonyl-and N-(ptolylsulfonyl)-2-(5-isothiocyanatocyclopent-1-en-1-yl)-6-methylanilines. N-Methylsulfonyl-2-(cyclopent-1-en-1-yl)-6-methylaniline reacted with bromine in methanol in the presence of NaHCO₃ or with CuBr₂ in MeOH to afford N-methylsulfonyl-2-(5-methoxycyclopent-1-en-1-yl)-6-methylaniline. The reaction of N-methylsulfonyl-2-(5-isothiocyanatocyclopent-1-en-1-yl)-6-methylaniline with diethylamine led to the formation of N-methylsulfonyl-2-{5-[diethylamino(thioxo)methyl]aminocyclopent-1-en-1-yl}-6-methylaniline which was converted into 5-methyl-4-methylsulfonyl-2,3,3a,4-tetrahydrocyclopenta[b]indole by heating with potassium hydroxide.     

Synthesis of 2-methyl-N-(2,2,2-trichloroethylidene)- and 2-methyl-N-(2,2,2-trichloroethyl)benzenesulfonamides from N,N-dichloro-2-methylbenzenesulfonamide and trichloroethylene

The reaction of N,N-dichloro-2-methylbenzenesulfonamide with trichloroethylene gave a new representative of highly electrophilic N-sulfonyl polyhaloaldehyde imines, 2-methyl-N-(2,2,2-trichloroethylidene) benzenesulfonamide. High reactivity of the product was demonstrated in the addition of water and 2-methylbenzenesulfonamide and reactions with benzene, toluene, anisole, thiophene, and 2-chlorothiophene. N,N-Dichlorobenzenesulfonamides and N,N-dichlorotrifluoromethanesulfonamide failed to react with 1,1,3,3,4,4-hexachlorobut-1-ene and 1,1,2,3,4-pentachlorobuta-1,3-diene under the conditions ensuring formation of N-(2,2,2-trichloroethylidene)arenesulfonamides from N,N-dichloroarenesulfonamides and trichloroethylene.     

Structures of four types of novel high-valent manganese complexes obtained by the reactions of KMnO4 with tridentate Schiff base ligands

X-ray structure analysis revealed that four types of novel manganese complexes, Mn^IV(N-EtO-sal)₂, Mn^III(N-PhO-sal)(L), [Mn^IV(5,6-Benzo-L)₂(μ-O)]₂ and Mn^III(L-4-Me)₃ have been found to be obtained by the reactions of KMnO₄ with various tridentate Schiff base ligands (N-EtOH-salH, N-PhOH-salH and its derivatives) in dry MeCN, where N-EtOH-salH, N-PhOH-salH, LH, 5,6-Benzo-LH and L-4-MeH denote N-2-hydroxyethyl-salicylideneamine, N-2-hydroxyphenyl-salicylideneamine, 2-(2-hydroxyphenyl)-benzoxazole 2-(2-hydroxynaphthyl)-benzoxazole and 2-(2-hydroxyphenyl)-5-methylbenzoxazole, respectively. The reactions of KMnO₄ and N-PhOH-salH and its derivatives have especially been found to afford benzoxazole derivatives which may be formed by intramolecular oxidative coupling between the phenolic oxygen atom of aminophenol moiety and the carbon atom of imine moiety.     

Ring opening of 2-(cyanomethyl)aziridines by acid chlorides: synthesis of novel 4-amino-2-butenenitrile derivatives through intermediate aziridinium salts

1-Arylmethyl-2-(cyanomethyl)aziridines were transformed into novel N-arylmethyl-N-(2-chloro-3-cyanopropyl)amides as the major reaction products upon treatment with acid chlorides in CH₂Cl₂ through the ring opening of intermediate aziridinium salts. Subsequently, N-arylmethyl-N-(2-chloro-3-cyanopropyl)amides were converted into stable N-arylmethyl-N-(3-cyano-2-propenyl)amides for the first time by means of a dehydrochlorination mediated by Et₃N in CH₂Cl₂.     

N-Polyfluoroethyl and N-2-chlorodifluorovinyl derivatives of azoles

Reactions of tetrafluoroethylene, chlorotrifluoroethylene and 1,2-dichlorodifluoroethylene with N-potassium salts of imidazole, 2-methylbenzimidazole, 3,5-dimethylpyrazole, 1,2,4-triazole, and benzotriazole lead to the formation of the corresponding N-(1,1,2,2-tetrafluoroethyl), N-(2-chloro-1,1,2-trifluoroethyl), and N-(2-chloro-1,2-difluorovinyl) azoles. Treatment of N-(2-chloro-1,2-difluorovinyl) and N-(2-chloro-1,1,2-trifluoroethyl) derivatives of azoles with tetramethylammonium fluoride is a useful synthetic method for the preparation of heterocycles with 1,2,2,2-tetrafluoroethyl group attached to nitrogen.     

Synthesis of N-arylcarbamates with tetrazole fragment and some their derivatives

Reactions of methyl(ethyl) N-(2-cyanophenyl)carbamates with sodium azide in dimethylformamide at 80–90°C in the presence of anhydrous CdCl₂ afforded the corresponding N-arylcarbamates with a 1,2,3,4-tetrazole fragment. The acylation of methyl N-[2-(1H-1,2,3,4-tetrazol-5-yl)phenyl]carbamate with acetic anhydride followed by the condensation of the obtained N-acyl derivative with thiophene-2-carbaldehyde in the KOH methanol solution led to the formation of methyl N-(2-{1-[3-(2-thienyl)-2-propenoyl]-1H-1,2,3,4-tetrazol-5-yl}phenyl)carbamate. The reaction of cyclohexyl N-(4-aminophenyl)carbamate with a triethyl orthoformate and sodium azide in glacial AcOH yielded cyclohexyl N-[4-(1H-1,2,3,4-tetrazol-1-yl)phenyl]carbamate.     

Synthesis and characterization of ruthenium p-cymene complexes bearing bidentate P–N and E–N ligands (E = S,Se) based on 2-aminopyridine

The syntheses and characterization of a series of cationic of Ru(II) halfsandwich complexes of the types [Ru(η⁶-p-cymene)(κ²(P,N)-PN)Cl]⁺ (PN = N-diphenylphosphino-2-aminopyridine, N-di-iso-propylphosphino-2-aminopyridine, 2-[(2-pyridyl)amino]dibenzo[d,f][1,2,3]dioxaphosphepine, N-(diisopropylphosphino)-2,6-diaminopyridine) and [Ru(η⁶-p-cymene)(κ²(E,N)-EN)Cl]⁺ (EN = N-(2-pyridinyl)amino-diphenylphosphine sulfide, N-(2-pyridinyl)amino-diisopropylphosphine sulfide, N-(2-pyridinyl)amino-diphenylphosphine selenide, N-(2-pyridinyl)amino-diisopropylphosphine selenide) is described. Some of these complexes were tested as precatalysts for the transfer hydrogenation of acetophenone to give 1-phenyl ethanol.     

Solid-state electrolytes based on ionic network polymers

Interpenetrating and semi-interpenetrating polymer networks are synthesized with the use of cationic and anionic ionic monomers: N-[3-(methacryloyloxy)propyl]-N-methylpyrrolidinium bis(trifluoromethane-sulfonyl)imide, N-[2-(2-(2-(methacryloyloxy)ethoxy)ethoxy)ethyl]-N-methylpyrrolidinium bis(fluorosulfonyl)imide, and (N-butyl-N-methylpyrrolidinium 1-[3-(methacryloyloxy)propylsulfonyl] (trifluoromethanesulfonyl) imide. Their ionic conductivities, electrochemical stabilities, heat resistances, thermal stabilities, and mechanical properties and the swelling of the films in ionic liquid/lithium salt mixtures were studied. The copolymerization of N-[2-(2-(2-(methacryloyloxy)ethoxy)ethoxy)ethyl]-N-methylpyrrolidinium bis(fluorosulfonyl)imide and poly(ethylene glycol dimethacrylate) and poly(ethylene glycol methacrylate) in the presence of butadiene-acrylonitrile rubber and a solution of Li(CF₃SO₂)₂N in N-(methoxymethyl)-N-methylpyrrolidinium bis(fluorosulfonyl)imide yielded a solid-state electrolyte with a set of properties optimum among the studied films: an ionic conductivity of 1.3 × 10^?4S/cm (25°C), a tensile strength of 80 kPa, and an elongation at break of 60%.     

A one-pot synthesis and mild cleavage of 2-[2- or 5-(alkylsulfanyl)pyrrol-1-yl]ethyl vinyl ethers by t-BuOK/DMSO: a novel and facile approach to N-vinylpyrroles

Substituted N-[2-(vinyloxy)ethyl]pyrroles, prepared in good yield through an allenic or acetylenic carbanion/isothiocyanate one-pot methodology from 2-(vinyloxy)ethyl isothiocyanate and allyloxyallene, methoxyallene, N,N-dimethyl-2-propyn-1-amine, and 3-methoxy-1-(methylsulfanyl)-1-propyne, are smoothly converted into the corresponding N-vinylpyrroles using t-BuOK/DMSO (room temperature). The reaction proceeds via elimination of vinyl alcohol from the N-[2-(vinyloxy)ethyl] substituent and represents a novel approach to N-vinylpyrroles.     

A short and efficient synthesis of N-aryl- and N-heteroaryl-N-(arylalkyl)piperazines

A new synthesis of N-aryl- and N-heteroaryl-N^′-(arylalkyl)piperazines using palladium-catalyzed amination of aryl bromides and heteroaryl chlorides with mono N-benzyl- or N-(arylethyl)piperazines is reported. Most coupling processes proceed in high yield and good selectivity using either diadamantyl-n-butylphosphine (1), 2-(dicyclohexylphosphino)-2^′-(N,N-dimethylamino)biphenyl (2), or 2-(di-tert-butylphosphino)biphenyl (3) as ligand. Applying an automated parallel synthesizer the preparation of a small library of potentially bioactive compounds is easily achieved.     

Synthesis of N-allyl- and N-acyl-2-vinylindoline

Heating a mixture of (2R*,3R*)- and (2R*,3S*)-2-[(1S*)-1-iodoethyl]-3,5-dimethyl-1-[(2-nitrophenyl) sulfonyl]indolines with N-isopropylpiperidine in xylene resulted in (2S*,3R*)-3,5-dimethyl-1-[(2-nitrophenyl) sulfonyl]-2-vinylindoline. The latter reacted with thiophenol to afford (2S*,3R*)-3,5-dimethyl-2-vinylindoline, whose reaction with allyl halides or acetyl bromide gave rise to N-allyl-, N-propenyl-, or N-acetyl derivatives. Nitration of 1-acetyl-3,5-dimethyl-2-vinylindoline yielded ortho-nitro derivative.     

Amidine derivatives of α-arylglycines from N-(1-aryl-2,2,2-trichloroethyl)amides of arenesulfonic acids and secondary amines

The interaction of N-(1-aryl-2,2,2-trichloroethyl)amides of arenesulfonic acids with secondary amines or their salts in the presence of inorganic bases involves the formation of chloroaziridine intermediates. Depending upon the solvent and reagent ratio, the reaction results in N-[1-dialkylamino-2-chloro-2-arylethylidene]-, N-[2-dialkylamino-1-chloro-2-arylethylidene]-, N-[1,2-bis(dialkylamino)-2-arylethylidene]-, and N-(1,2-dioxo-2-arylethene)amides of arenesulfonic acids.