The Preparation of 2-(2-Oxo-2-Phenylethyl) Benzoic Acids from Dilithiated Ortho-Toluic Acid.

ortho-Toluic acid was dimetalated with excess lithium diisopropylamide, and the resulting intermediate was condensed with a variety of aromatic esters to afford new substituted 2-(2-oxo-2-phenylethyl)benzoic acids (ortho-phenacylbenzoic acids).     

Electron impact induced fragmentations of 2-(2-nitroanilino)thiophens and Di(2-nitrophenyl)sulphides

A prominent ortho interaction occurs during the mass spectral fragmentation of di(2-nitrophenyl)sulphides. No such effects are observed for the corresponding ethers or 2-(2-nitroanilino)thiophens. Variation of aromatic substituents can dramatically alter the effect. Examination of analogous sulphone, sulphoxide, and disulphide molecules, implicates the involvement of the ortho nitro substituent and the sulphur atom in this rearrangement.     

1H NMR spectra of some nitro derivatives of 2-alkylamino-, 2-phenylamino-, 2-piperidyl-, 2-morpholyl-, 2-(N-alkyl-N-nitrosoamino)-, and 2-alkylnitramino-4(or 6)-methylpyridines

¹H NMR spectra of some N-substituted 2-amino-3-nitro-and 2-amino-5-nitropyridines were measured and interpreted. Chemical shift assignments were based on existing chemical shift rules for substituted pyridines and spectral comparison with compounds of similar structure. The splitting of the methyl group signal of the methylamino group into a doublet testifies that the investigated compounds exist, in the amino form. Someortho-amino- andortho-alkylaminonitropicolines were found to give splitting of the amino signals due to intramolecular hydrogen bonding and steric hindrance.Department of Organic Chemistry, Academy of Economics, PL-53 432 Wroclaw, Poland. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 637–642, May, 1997.     

Indoledione-indole rearrangement (review)

The indoledione-indole rearrangement, which occurs during the basic condensation ofortho-aminophenylcarbonyl compounds (ortho-aminophenylglyoxylic acid,ortho-aminoketones) with halomethylketones, is reviewed.Institute of Biological Plant Protection, Academy of Sciences of the Moldavian Republic, Kishinev 2058. Translated from Khimiya Geteorotsiklicheskikh Soedinenii, No. 9, pp. 1170–1180, September, 1998.     

A Novel Method for the Synthesis of 2(3H)‐Benzimidazolones, 2(3H)‐Benzoxazolone,and 2(3H)‐Benzothiazolone via In Situ Generated Ortho Substituted Benzoic Acid Azides: Application of Ammonium Azide and Vilsmeier Complex for Acid Azide Generation

Abstract

An easy and generalized route to 2(3H)‐benzimidazolones, 2(3H)‐benzoxazolone and 2(3H)‐benzothiazolone is attempted. A novel one‐pot method for the in situ generation and cyclisation of ortho substituted benzoic acid azides is reported via the application of ammonium azide and Vilsmeier complex.     

Photolyse von 3-Methyl-2, 1-benzisoxazol (3-Methylanthranil) und 2-Azido-acetophenon in Gegenwart von Schwefelsäure und Benzolderivaten

Photolysis of 3-Methyl-2, 1-benzisoxazole (3-Methylanthranil) and 2-Azido-acetophenone in the Presence of Sulfuric Acid and Benzene Derivatives Irradiation of 3-methylanthranil ( 1 ) in acetonitrile in the presence of sulfuric acid and benzene, toluene, p-xylene, mesitylene or anisole with a mercury high-pressure lamp through a pyrex filter yields beside varying amounts of 2-amino-acetophenone ( 3 ) and 2-amino-5-hydroxy- ( 4a ) and 2-amino-3-hydroxy-acetophenone ( 4b ) the corresponding diphenylamine derivatives 5 (see Table 1). In the case of toluene and anisole mixtures of the corresponding ortho- and para-substituted isomers ( 5b, 5d or 5g, 5i respectively), but no meta-substituted isomers ( 5c or 5h ) are obtained. In addition to these products, the irradiation of 1 in the presence of anisole yields also 2-amino-5-(4′-methoxyphenyl)-acetophenone ( 7 ), 2-amino-3-(4′-methoxyphenyl)-acetophenone ( 8 ) and 2-methoxy-9-methyl-acridine ( 6 ; see Scheme 1). The latter product is also formed thermally by acid catalysis from the diphenylamine derivative 5i . Irradiation of 2-azido-acetophenone ( 2 ) in acetonitrile solution in the presence of sulfuric acid and benzene leads to the formation of 1, 3, 4a, 4b, 5a and 9 (see Table 2). Compounds 3, 4a, 4b and 5a are also obtained after acid catalyzed decomposition of 2 in the presence of benzene. Thus, it is concluded that irradiation of 1 or 2 in the presence of sulfuric acid yields 2-acetyl-phenylnitrenium ions 10 in the singlet ground state which will undergo electrophilic substitution of the aromatic compounds, perhaps via the π-complex 11 (see Scheme 2).     

Ru–η6‐Arene Cations [{(Ph2PC6H4)2B(η6‐Ph)}RuX]+ (X=Cl,H) as Lewis Acids

The reactivity of [{(Ph₂PC₆H₄)₂B(η⁶‐Ph)}RuCl][B(C₆F₅)₄] ( 1 ) as a Lewis acid was investigated. Treatment of 1 with mono and multidentate phosphorus Lewis bases afforded the Lewis acid–base adducts with the ortho‐carbon atom of the coordinated arene ring. Similar reactivity was observed upon treatment with N‐heterocyclic carbenes; however, adduct formation occurred at both ortho‐ and para‐carbon atoms of the bound arene with the para‐position being favoured by increased steric demands. Interestingly treatment with isocyanides resulted in adduct formation with the B‐centre of the ligand framework. The hydride‐cation [{(Ph₂PC₆H₄)₂B(η⁶‐Ph)}RuH] [B(C₆F₅)₄] was prepared via reaction of 1 with silane. This species in the presence of a bulky phosphine behaves as a frustrated Lewis pair (FLP) to activate H₂ between the phosphorus centre and the ortho‐carbon atom of the η⁶‐arene ring.     

Reactions of N- and C-Alkenylanilines: I. Synthesis of Anilides and Amidines from ortho-Alkenyl(cycloalkenyl)anilines and Their Transformations

N-Acetyl- and N-formyl-ortho-alkenyl(cycloalkenyl)anilines were synthesized. Their reaction with P2O5 or PCl5 afforded quinolines. By reaction of the ortho-alkenyl(cycloalkenyl)anilines with 1-methylimino- or 1-phenylimino-1-chloroethanes amidines were obtained that were cyclized in the polyphosphoric acid. The reaction with the polyphosphoric acid of amidines prepared from alkenylanilines and 1-methylimino-1-chloroethane gave rise to 3-methyl-3,4-dihydroquinazolines; on replacing in the substrate methylimine group for phenylimine one the yield of quinazoline decreased.     

Synthesis of potential fungicides based on N-(3-furanyl)pyrrolecarboxamides and N-(3-furanyl)pyrazolecarboxamides

Abstract  

An efficient synthesis of novel N-(3-furanyl)pyrrolecarboxamides and N-(3-furanyl)pyrazolecarboxamides is presented starting from furan-3-carboxylic acid. Two complementary strategies to 2-aryl-3-furanamines with directed ortho lithiation, functionalization of the 2-position, and subsequent cross-coupling reaction as key steps were developed. Acylation of these intermediates with appropriate acid chlorides led finally to the target compounds.     

Application of Organolithium and Related Reagents in Synthesis, Part 29 [1]. A Concise Regiospecific Conversion of Benzoic Acids into 5-(2-Carboxyphenyl)-5-phenylpent-2-enoic Acids

A convenient two-step protocol preparation of ortho-alkylated (substituent with the carbomethoxy group at the end of five carbon atoms alkyl chain) aromatic carboxylic acids from benzoic acids anilides is described. Ortho-lithiation of benzanilides and subsequent reaction of the generated bis(N- and C-ortho-)-lithiated anilides with aromatic aldehydes provided 3-arylphthalides. In the next step, these phthalides were converted into 5-(2-carboxyphenyl)-5-phenylpent-2-enoic acids by treatment with 1-methoxy-1-trimethylsilyloxybuta-1,3-diene.     

Application of Organolithium and Related Reagents in Synthesis,Part 29 [1]. A Concise Regiospecific Conversion of Benzoic Acids into 5-(2-Carboxyphenyl)-5-phenylpent-2-enoic Acids

Summary. A convenient two-step protocol preparation of ortho-alkylated (substituent with the carbomethoxy group at the end of five carbon atoms alkyl chain) aromatic carboxylic acids from benzoic acids anilides is described. Ortho-lithiation of benzanilides and subsequent reaction of the generated bis(N- and C-ortho-)-lithiated anilides with aromatic aldehydes provided 3-arylphthalides. In the next step, these phthalides were converted into 5-(2-carboxyphenyl)-5-phenylpent-2-enoic acids by treatment with 1-methoxy-1-trimethylsilyloxybuta-1,3-diene.     

Synthesis and characterization of poly(2-amino-2-methylpropyl)acrylamide,poly(2-amino-2-methylbutyl)acrylamide,and copolymers of polyacrylamide

Polyacrylamides possessing an amino group at the terminus of the branch chain as the potential site for amino acid and/or nucleic acid base grafting have been prepared. This type of polyacrylamide would provide a substantial spacing distance between the polymer main chain and pendant groups. Poly(2-amino-2-methylpropyl)acrylamide (PDMPA) and optically active poly(2-amino-2-methylbutyl)acrylamide (PDMBA) were characterized using vapor phase osmometry (VPO), gel permeation chromatography (GPC), and dilute solution viscometry. In addition, copolymers of poly(2-amino-2-methylpropyl)acrylamide with N-vinylpyrrolidinone, N-vinylimidazole, and H(5)-vinylimidazole, were prepared.     

Synthesis, XRD structure and properties of diaqua(p-toluidine-N,N-di-3-propionato)copper(II) dihydrate [Cu(p-Tdp)(H2O)2]·2H2O

The copper(II) complex [Cu(p-Tdp)(H₂O)₂]·2H₂O, where p-Tdp is the anion of p-toluidine-N,N-di-3-propionic acid (or N,N-di(2-carboxyethyl)-p-toluidine), has been synthesized and characterized by X-ray diffraction. Three crystallographically independent [Cu(p-Tdp)(H₂O)₂] molecules have a similar structure. The Cu atoms have a square pyramidal environment (4+1) with a small trigonal bipyramidal distortion. The ortho-H atom of the benzene ring blocks up the sixth coordination position of the Cu polyhedron. The basal plane is formed by the donor atoms of the tridentate ligand and by the water molecule (average bond length Cu---N 2.03, Cu---O 1.93, Cu---O_w 2.00 Å), the apex is occupied by another water molecule (Cu---O_w 2.27 Å). The Cu atoms are located 0.20–0.30 Å out of the mean planes of the four basal atoms towards the apical O_w atom. The IR and electronic absorption spectra of p-Tdp and the title compound have been described. UV–Vis reflectance spectra shows that the complex has the same square pyramidal geometry in the crystal state and in solution. The protonation constants of the ligand log K₁=6.87(2), log K₂=3.75(2), log K₃=2.57(2) and stability constants log K_CuH(p-Tdp)=2.13(5), log K_Cu(p-Tdp)=6.38(3) were determined by pH-titration at 25.0 °C and I=0.1 M KNO₃.     

Dihydrogen Activation with a Neutral,Intermolecular Silicon(IV)-Amine Frustrated Lewis Pair

The heterolytic cleavage of dihydrogen constitutes the hallmark reaction of frustrated Lewis pairs (FLP). While being well-established for planar Lewis acids, such as boranes or silylium ions, the observation of the primary H₂ splitting products with non-planar Lewis acid FLPs remained elusive. In the present work, we report bis(perfluoro-N-phenyl-ortho-amidophenolato)silane and its application in dihydrogen activation to a fully characterized hydridosilicate. The strict design of the Lewis acid, the limited selection of the Lewis base, and the distinct reaction conditions emphasize the narrow tolerance to achieve this fascinating process with a tetrahedral Lewis acid.     

Chiral N,N′‐Dioxide–Scandium(III) Complex‐Catalyzed Asymmetric Friedel–Crafts Alkylation Reaction of ortho‐Hydroxybenzyl Alcohols with C3‐Substituted N‐Protected Indoles

The first Lewis acid catalyzed asymmetric Friedel–Crafts alkylation reaction of ortho‐hydroxybenzyl alcohols with C3‐substituted indoles is described. A chiral N,N′‐dioxide Sc(OTf)₃ complex served not only to promote formation of ortho‐quinone methides (o‐QMs) in situ but also induced the asymmetry of the reaction. This methodology enables a novel activation of ortho‐hydroxybenzyl alcohols, thus affording the desired chiral diarylindol‐2‐ylmethanes in up to 99 % yield and 99 % ee. A range of functional groups were also tolerated under the mild reaction conditions. Moreover, this strategy gives concise access to enantioenriched indole‐fused benzoxocines.     

Prediction of ortho(β) 13C chemical shifts in conjugated systems

An equation has been developed which relates ortho or C-β ¹³C substituent chemical shifts (SCS) to the ortho proton–proton coupling constant in the unsubstituted member of a conjugated series. This method is an extension of previous equations which have been used to predict ortho ¹H SCS values, and has its origin in a relationship between bond order and SCS values. The equation was derived from ortho ¹³C data in 2-naphthalenes and monosubstituted benzenes and its application to other unsaturated series is discussed.     

S‐((Phenylsulfonyl)difluoromethyl)thiophenium Salts: Carbon‐Selective Electrophilic Difluoromethylation of β‐Ketoesters, β‐Diketones,and Dicyanoalkylidenes

S‐((Phenylsulfonyl)difluoromethyl)thiophenium salts were designed and prepared by a triflic acid catalyzed intramolecular cyclization of ortho‐ethynyl aryldifluoromethyl sulfanes. The thiophenium salts were found to be efficient as electrophilic difluoromehtylating reagents for introduction of a CF₂H group to sp³‐hybridized carbon nucleophiles such as of β‐ketoesters and dicyanoalkylidenes. The (phenylsulfonyl)difluoromethyl group can be readily transformed into CF₂H under mild reaction conditions. Enantioselective electrophilic difluoromethylation was also achieved in the presence of bis(cinchona) alkaloids.     

S‐((Phenylsulfonyl)difluoromethyl)thiophenium Salts: Carbon‐Selective Electrophilic Difluoromethylation of β‐Ketoesters, β‐Diketones,and Dicyanoalkylidenes

S‐((Phenylsulfonyl)difluoromethyl)thiophenium salts were designed and prepared by a triflic acid catalyzed intramolecular cyclization of ortho‐ethynyl aryldifluoromethyl sulfanes. The thiophenium salts were found to be efficient as electrophilic difluoromehtylating reagents for introduction of a CF₂H group to sp³‐hybridized carbon nucleophiles such as of β‐ketoesters and dicyanoalkylidenes. The (phenylsulfonyl)difluoromethyl group can be readily transformed into CF₂H under mild reaction conditions. Enantioselective electrophilic difluoromethylation was also achieved in the presence of bis(cinchona) alkaloids.     

A convenient synthesis of nitro-substituted 1,2-benzisothiazol-3(2H)-one 1,1-dioxides (nitrosaccharins)

Nitro-substituted 1,2-benzisothiazol-3(2H)-one 1,1-dioxides (nitrosaccharins) have been synthesized by amminolysis of nitro 2-chlorosulfonylbenzoate esters. This method appears to have advantages over the original procedure of oxidation of an ortho-toluenesulfonamide.     

Thermal Study of [Pd(2-Phpy)Cl(L)] Complexes (L=pyridines and amines)

The complex [Pd(2-Phpy)(μ-Cl)]₂ reacts with pyridines (L=pyridine, α-picoline and γ-picoline), amines (L=isopropylamine, tert-butylamine) and ammonia to form the corresponding ortho-palladatedderivatives [Pd(2-Phpy)ClL]. The compounds have been characterized by C, H and Nanalyses and spectroscopic methods (IR and ¹H and ¹³C NMR).TG, DTG and DSC studies of the complexes were carried out in dynamic nitrogen atmosphere. From DSC analyses the heats of decomposition were calculated. The kinetics ofthe first step of thermal decomposition were evaluated from TG data by isothermal methods for L=pyridine and isopropylamine. The activation energies obtained are in the range 90–100 kJ mol^-1. The best fitting for data was observed for R2 and A1.5 kinetic models. This revised version was published online in August 2006 with corrections to the Cover Date.