2-(Prenyloxymethyl)benzoyl (POMB) group: a new temporary protecting group removable by intramolecular cyclization

2-(Prenyloxymethyl)benzoates can be prepared from alcohols and readily available 2-(prenyloxymethyl)benzoic acid by standard acylation techniques or by Mitsunobu reaction with inversion of configuration. The POMB group can be cleaved first by oxidative removal of the prenyl group with DDQ followed by lactonization with expulsion of the alcohol catalyzed by Yb(OTf)₃. These reaction conditions are compatible with the presence of a large number of common protecting groups.     

Reactions of <Emphasis Type="Italic">N</Emphasis>-(Perfluorophenyl)carbonimidoyl Dichloride with Aromatic Acids and Their Derivatives in the Presence of AlCl<Subscript>3</Subscript>. Formation of 2-(Perfluorophenyl)isoindoline-1,3-dione and Its Derivatives

Reactions of N-(perfluorophenyl)carbonimidoyl dichloride with benzoic acid, benzoyl chloride, ethyl benzoate, and also with phthalic acid, phthaloyl dichloride, and phthalic anhydride in the presence of AlCl₃ at 170°C afford2-(perfluorophenyl)isoindoline-1,3-dione. With benzoic acid and benzoyl chloride form also 2-(perfluorophenyl)-3-[(perfluorophenyl)imino]isoindolin-1-one. In reactions with compounds of the benzene series arise also derivatives of arylimidoyl chlorides and amide type compounds containing a CONHC₆F₅ moiety.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 2, 2005, pp. 228–236.Original Russian Text Copyright © 2005 by Petrova, Platonov.     

Mixed ligand complexes of tungsten(VI) containing aroyl hydrazones and isothiocyanate

Five complexes [WO(NCS)₄L–L] (where L–L = benzoic acid[1-(Furan-2-yl)methylene]hydrazide(BFMH), benzoic acid[(thiophen-2-yl)methylene]hydrazide(BTMH), benzoic acid[1-(thiophen-2-yl)ethylidene]hydrazide(BTEH), benzoic acid(phenylmethylene)hydrazide(BPMH) and benzoic acid[1-(anisol-3-yl) methylene]hydrazide(BAMH)) have been prepared by reaction of ammonium tetraisothiocyanatodioxotungstate(VI) with the corresponding ligand in aqueous medium in the presence of hydrochloric acid. The complexes have been characterized by elemental analysis, molar conductivity, magnetic moment measurements, IR, electronic spectra, thermogravimetric analysis TGA/DTA and ¹H NMR.     

Pyrazolidine-3,5-dione angiotensin-II receptor antagonists

The crystal structures of three angiotensin-II receptor antagonists involving different spacer groups (CO, CONH and NHCO) between the aryl rings are presented, namely 2-{4-[(3-butyl-1,4-dioxo-2,3-di­aza­spiro­[4.4]­non-2-yl)­methyl]­benzoyl}benzoic acid, C₂₆H₂₈N₂O₅, (I), 2-{4-[(3-butyl-1,4-dioxo-2,3-di­aza­spiro­[4.4]­non-2-yl)­methyl]­benz­amido}benzoic acid, C₂₆H₂₉N₃O₅, (II), and 2-{4-[(3-butyl-1,4-dioxo-2,3-di­azaspiro­[4.4]­non-2-yl)­methyl]­anilino­carbonyl}benzoic acid monohydrate, C₂₆H₂₉N₃O₅·H₂O, (III). The aryl rings of (II) are almost coplanar, in contrast with compounds (I) and (III). The conformation of (II) is induced by an intramolecular N—H⋯O hydrogen bond between the amide and carboxyl­ic acid groups.     

PHOTOOXYGENATION OF BIPHENYL AND ITS DERIVATIVES via PHOTOINDUCED ELECTRON TRANSFER: EFFECT OF Mg(CIO4)2 ON PHOTOOXYGENATION

The 9,10-dicyanoanthracene (DCA)-sensitized photooxygenation of biphenyl derivatives in the presence of Mg(CIO₄)₂ in acetonitrile produces benzoic acid and its derivatives in high yields. In the absence of Mg(CIO₄)₂, the rates for the consumption of biphenyl derivatives decrease by a factor of 0.5-0.8, compared with those in the presence of Mg(CIO₄)₂. In these cases, however, both biphenyls and DCA are oxygenated to give benzoic acids and anthraquinone, respectively, indicating that the addition of Mg(CIO₄)₂ retards the photooxygenation of DCA. With 4-methylbiphenyl, the photooxygenation proceeds efficiently without added Mg(CIO₄)₂, and benzene rings and methyl groups are competitively oxygenated to give benzoic acid, 4-methylbenzoic acid, 4-phenylbenzoic acid, and 4-phenylbenzaldehyde. The addition of Mg(CIO₄)₂ facilitates the oxidation of benzene rings, giving benzoic acid and 4-methylbenzoic acid as major products. These photooxygenations are initiated by a one-electron transfer from biphenyls to the excited singlet DCA and proceed via the radical cations of biphenyls and the radical anion of DCA.     

X‐(Diiodoarsanyl)benzoic acid (X = 3 and 4)

The title compounds, 4‐(diiodoarsanyl)benzoic acid, (I), and 3‐(diiodoarsanyl)benzoic acid, (II), both [As(C₇H₅O₂)I₂], which possess a –COOH coordinating group, form molecular crystal structures composed of hydrogen‐bonded dimers, the packing differences of which are caused by the relative position of the diiodoarsanyl groups. The para isomer, with Z′ = 1, crystallizes in a layered structure with shortened contacts of the As atoms to only the arene rings of adjacent molecules. In contrast, the meta isomer, with Z′ = 3, forms separate rectangular blocks of three ribbons, each composed of dimeric molecular units positioned almost directly above each other and with the As atoms possessing only two As...I contacts to the I atoms of neighbouring molecules.     

Mössbauer and other spectral studies of iron(II) complexes with amide-containing ligands

Summary Iron(II) complexes of the type [FeL₂X₂] (L=bidentate ligand, X=H₂O, Cl, or SCN) and [FeL₂] (L=tridentate ligand) with polydentate ligands derived from 2-(acetylamino)benzoic acid, 2-(benzoylamino)benzoic acid,2-[2-aminobenzoylamino]benzoic acid, 2-[amino-carbonyl]benzoic acid, 2-[(phenylamino)carbonyl]-benzoic acid, 2-[aminobenzoyl]benzoic acid and 2-aminobenzanilide have been synthesized and characterized by elemental analyses, conductivity, magnetic susceptibility and i.r., electronic, n.m.r., and Mossbauer spectral studies. The different modes of ligand chelation and the stereochemistry around the metal ion are discussed. The small range of isomer shift values for iron(II) complexes confirms the similar geometry for all the complexes.     

Preparation of new supramolecular liquid-crystalline polyesters containing 3-chloro-4-(alkoxy)benzoic acids

Supramolecular liquid-crystalline polyester complexes based on intermolecular hydrogen bonds between the carboxylic group and the pyridyl moieties was prepared by using non-liquid-crystalline H-donors, [3-chloro-4-(butyloxy)benzoic acid (2a), 3-chloro-4-(octyloxy)benzoic acid (2b), 3-chloro-4-(dodecyloxy)benzoic acid (2c) and 3-chloro-4-(tetradecyloxy)benzoic acid (2d)] and H-acceptor-polyester containing pyridyl units. Intermolecular hydrogen bond formation was confirmed by Fourier transform infrared spectroscopy. The liquid-crystalline behavior of the complex formed was established by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). The polyester complexes containing 2c and 2d donor components exhibit liquid crystalline mesophase and behave as side-chain liquid-crystalline polymers. Compared with unsubstituted parent acid, the presence of chloro group as a lateral substituent has a little negative effect on the induction of liquid crystallinity on the polyester complexes systems. The results show that the more stability of the obtained H-bonded complexes in comparison with analogues without 3-Cl substituents is due to the increased acidity of benzoic acid moiety.     

Synthesis of the penta-glutamyl derivative of N-[4-[N-[3-(2,4-diamino-1,6-dihydro-6-oxo-5-pyrimidinyl)-propyl]amino]benzoyl]-L-glutamic acid (5-DACTHF). An acyclic analogue of tetrahydrofolic acid

The penta-glutamyl derivative of N-[4-[N-[3-(2,4-diamino-1,6-dihydro-6-oxo-5-pyrimidinyl)propyl]amino]-benzoyl)-L-glutamic acid (1, 5-DACTHF, 543U76) was synthesized by a convergent route. L-γ-Glutamyl-L-γ-glutamyl-L-γ-glutamyl-L-γ-glutamyl-L-γ-glutamyl-L-glutamic acid heptakis t-butyl ester ( 20 ) was prepared in ten steps from L-glutamic acid di-t-butyl ester and N-(benzyloxycarbonyl)-L-glutamic acid α-t-butyl ester. 4-[N-[3-(2,4-Diamino-1,6-dihydro-6-oxo-5-pyrimidinyl)propyl]trifluoroacetamido]benzoic acid ( 6 ), which was synthesized from pyrimidinylpropionaldehyde 3 in three steps, was condensed with 20 , followed by deprotection to provide N-[4-[N-[3-(2,4-diamino-1,6-dihydro-6-oxo-5-pyrimidinyl)propyl]amino]benzoyl]-L-γ-glutamyl-L-γ-glutamyl-L-γ-glutamyl-L-γ-glutamyl-L-γ-glutamyl-L-glutamic acid ( 2 ). Hexaglutamate 2 is a potent inhibitor of glycinamide ribonucleotide transformylase.     

Heteroatomic derivatives of aziridine. 12. Reaction of 1-(carbomethoxyalkyl)aziridines with thiols and mercapto acids

The reaction of 1-(carbomethoxyalkyl)aziridines with thiols and mercapto acids, which leads to the formation of the corresponding sulfides and esters of S-substituted N-(2-mercaptoethyl)amino acids, was studied. The acid hydrolysis of o-[(N-carbomethoxyethyl)-2-aminoethylthio]benzoic acid and o-[(N-cyanoethyl)-2-aminoethylthio]benzoic acid leads to o-[N-(carboxyethyl)-2-aminoethylthio]benzoic acid hydrochloride. The cyclization of 1-[(N-carbomethoxyethyl)-2-aminoethylthio]benzoic acid in the presence of PCl₃ gives 5-oxo-4-(carbomethoxyethyl)-6,7-benzoperhydro-1,4-thiazepine.See [1] for communication 11.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 921–923, July, 1981.     

3-(Hetarylamino)- and 3-[(hetarylmethyl)amino]-isoquinolin-1(2H)-ones

The reaction of 2-(cyanomethyl)benzoic acid with amines RNH₂ (R = Ar, Het, CH₂Ar, CH₂Het) leads to the formation of the corresponding 3-NHR-isoquinolin-1(2H)-ones. When R = CH₂Ar and CH₂Het, there is a side reaction involving hydrolysis of the hydrolytically-unstable intermediates, derivatives of 2-(2-amino-2-iminoethyl)benzoic acid, leading to 2-R-isoquinoline-1,3(2H,4H)-diones.     

N‐(2‐Carboxy­benzoyl)‐l‐leucine methyl ester

The title compound (with the systematic name 2‐{[(1S)‐1‐(methoxy­carbonyl)‐3‐methyl­butyl]amino­carbonyl}benzoic acid), C₁₅H₁₉NO₅, crystallizes in the monoclinic space group P2₁, with two independent mol­ecules per asymmetric unit. The most notable difference between the two mol­ecules is in the dihedral angles between the planes of the carboxyl group and the benzene ring, which are 3.5 (3) and 25.7 (1)°. This difference may account for the fact that two competing reactions are observed in aqueous solution, namely cyclization to form the imide N‐phthaloyl­leucine and hydrolysis of N‐(2‐carboxy­benzoyl)‐l ‐leucine methyl ester to phthalic acid and leucine.     

Synthesis of new 4-amino-5-(1,4-benzodioxan-2-yl)-4<Emphasis Type="Italic">H</Emphasis>-1,2,4-triazole-3-thiol derivatives

Acylation and cyclization reactions of 4-amino-5-(1,4-benzodioxan-2-yl)-4H-1,2,4-triazole-3-thiol were studied. Acylation of the title compound with substituted benzoyl chlorides gave the corresponding amides, whereas its reactions with substituted benzoic acids in the presence of POCl3 were accompanied by cyclization with formation of triazolothiadiazoles containing a 1,4-benzodioxane substituent. 4-Amino-5-(1,4-benzodioxan-2-yl)-4H-1,2,4-triazole-3-thiol reacted with substituted benzaldehydes to afford the corresponding Schiff bases, and its alkylation with chloroacetic acid in ethanol in the presence of sodium acetate gave S-ethoxycarbonylmethyl derivative.     

Synthesis of (-)-tetracycline

We describe a convergent, enantioselective synthesis of (-)-tetracycline (1) from benzoic acid (17 steps, 1.1% yield). Benzoic acid was transformed into the AB precursor 2 in 10 steps (11% yield), as previously described, and the latter compound was activated toward Diels-Alder cycloaddition by the introduction of an alpha-phenylthio group (two steps, 66% yield). Heating of the resulting alpha-(phenylthio)enone (3) with the triethylsilyloxybenzocyclobutene derivative 4 at 85 degrees C gave the endo-Diels Alder adduct 5 in 64% yield. Deprotection and oxidation of the latter intermediate gave the 2-(phenylthio)-1,3-diketone 7, which was oxidized with m-chloroperoxybenzoic acid in the presence of trifluoroacetic acid. The sulfoxide intermediate(s) formed eliminated upon warming to 35 degrees C to give the anyhydrotetracycline derivative 8. Intermediate 8 underwent spontaneous autoxidation at 23 degrees C to form the hydroperoxide keto-9 stereoselectively. Without isolation, hydrogenolysis of 9 in the presence of palladium black gave (-)-tetracycline (42% yield from 7), indistinguishable from an authentic sample.     

Thermal Behaviour of Copper(II) Complexes of Haloaspirinates

Complexes of Cu(II) with substituted o-acetoxy benzoic acids (5-haloaspirines, X-asp) with and without pyridine (py), of composition [Cu₂(X-asp)₄] and [Cu(X-asp)₂(py)₂ ] have been synthesized and characterized. Electronic and vibrational spectroscopic data of these complexes are reported. Its thermal behaviour was investigated by thermogravimetry and differential thermal analysis. In all complexes, the haloaspirinate ligands decompose in two or three steps, starting with the break up of the coordinated acetoxy groups. CuO is obtained as the final pyrolysis residue in all cases. This revised version was published online in August 2006 with corrections to the Cover Date.     

Halogeno(triazolyl)zinc complexes as molecular building blocks for metal–organic frameworks

The isomorphous title complexes, dichlorido[4‐(3,5‐dimethyl‐4H‐1,2,4‐triazol‐4‐yl)benzoic acid‐κN¹]zinc(II) dihydrate, [ZnCl₂(C₁₁H₁₁N₃O₂)₂]·2H₂O, and dibromido[4‐(3,5‐dimethyl‐4H‐1,2,4‐triazol‐4‐yl)benzoic acid‐κN¹]zinc(II) dihydrate, [ZnBr₂(C₁₁H₁₁N₃O₂)₂]·2H₂O, were synthesized and crystallized by slow evaporation of the solvent from a solution of the ligand and either zinc chloride or zinc bromide, respectively, in water/ethanol. The Zn^II ions occupy twofold axes in the noncentrosymmetric orthorhombic space group Fdd2. The metal ion is approximately tetrahedrally coordinated by two monodentate triazole groups of the ligands and additionally by two halide ions. The water molecules incorporate the complexes into a three‐dimensional framework made up by hydrogen bonds. Furthermore, each complex possesses two hydrogen‐bond‐donor sites represented by the carboxy groups and two acceptor sites at the noncoordinating N atoms of the triazoles.     

Synthesis,crystal structures,and antitumor activity of three new organotin carboxylates

Three new organotin(IV) carboxylates of composition [(R)₂Sn(O₂CC₆H₄C‐OC₆H₄CH₃)₂] 1 , [(R)₂Sn(O₂CC₆H₄COC₆H₄‐C₂H₅)₂]₂ 2 , and R₃SnO₂ CC₆H₄COC₆H₄CH₃ 3 , were obtained by reactions of (R)₂SnO [R = o‐tolyl] with 2‐(4‐methyl benzoyl) benzoic acid and 2‐(4‐ethyl benzoyl) benzoic acid, and reaction of Cy₃SnOH [Cy = cyclohexyl] with 2‐(4‐methyl benzoyl) benzoic acid, respectively. The complexes 1 , 2 and 3 have been characterized by elemental analysis, infrared (IR), ¹HNMR, and X‐ray crystallography diffraction analyses. The complex 1 has two folded symmetrical structure; the tin atom in 1 is found to adopt a distorted toward skew‐trapezoidal bipyramidal geometry. Molecular structure of the complex 2 is centrosymmetric, and the internal tin atom is five‐coordinated and is in distorted trigonal bipyramidal geometry. The crystal structure of the complex 3 is found to exhibit distorted tetrahedral geometry. Pilot studies have indicated that the complexes 1 and 2 have shown good antitumor activities. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:304–313, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20614     

Conformational polymorphism of 3-(azidomethyl)benzoic acid

Three conformational polymorphs of 3-(azidomethyl)benzoic acid, C₈H₇N₃O₂, are reported. All three structures maintain similar carboxylic acid dimers and π–π stacking. Crystal structure analysis and computational evaluations highlight the azidomethyl group as a source of conformational polymorphism, thus having potential implications in the design of solid-state reactions.     

Synthesis of aromatic polyethers by Scholl reaction. V. Synthesis and polymerization of 1,3-bis[4-(1-naphthoxy) benzoyl]benzene, 1,4-bis[4-(1-naphthoxy)benzoyl]benzene,bis[4-(1-naphthoxy)phenyl]methane, 1,3-bis[4-(1-naphthoxy) phenylmethyl]benzene,and 1,4-bis-[4-(1-naphthoxy)phenylmethyl]benzene

This article describes the synthesis and the cation-radical polymerization (Scholl reaction) of 1,3-bis[4-(1-naphthoxy) benzoyl] benzene ( 6 ) and 1,4-bis[4-(1-naphthoxy) benzoyl]- benzene ( 7 ) initiated by FeCI₃. This polymerization produced poly(ether ether ketone ketone)s (PEEKK) of number average molecular weight (M?_n) up to 5400 g/mol. The synthesis of bis[4-(1-naphthoxy) phenyl] methane ( 8 ), 1,3-bis[4-(1-napthoxy) phenylmethyl] benzene ( 9 ), and 1,4-bis[4-(1-naphthoxy) phenylmethyl] benzene ( 10 ) are also described. Polyethers of M?_n up to 15400 g/mol at a FeCl₃/monomer molar ratio of 2/1 were obtained. An increased polymerizability of the monomers 9 and 10 containing two CH₂ groups versus that of the corresponding monomers containing two carbonyl groups ( 6 and 7 ) was observed. This enhanced polymerizability was explained based on the increased nucleophilicity of monomers 9 and 10 .     

Thermal stability of amino acid-(tyrosine and tryptophan) coated magnetites

The thermal stability of two amino acid-(tyrosine and tryptophan) coated magnetite and their corresponding precursors, [Fe₂^IIIFe^II(Tyr)₈]·9H₂O and [Fe₂^IIIFe^II(Trp)₂(OH)₄](NO₃)₂·8H2O (where tyrosine=Tyr and tryptophan=Trp), was analyzed in comparison with free amino acids. The complexes present a lower thermal stability relative to the free ligand, due to the catalytic effect introduced by the iron cation and the presence of NO₃⁻ groups. The presence of NO₃⁻ group determines also a different degradation’s stoichiometry of the amino acid anion comparative with the one expressed by the free ligand molecule. The amino acid bonded to magnetite decomposes in two steps, its presence inducing an increasing of γ-Fe₂O₃→Fe₂O₃ conversion temperature.