P-bromobenzoic Acid Research Articles

Long-wavelength Fluorogenic Derivatization of Aryl Halides Based on the Formation of Stilbene by Heck Reaction with Vinylbenzenes.

The long-wavelength fluorogenic derivatization method for aryl halides was developed based on stilbene formation by the Heck coupling reaction between aryl halides and vinylbenzenes in the presence of palladium(II) acetate as a catalyst. Fluorescent maximum wavelengths of the derivative obtained by the proposed reaction were 365 - 450 nm, which were 50 - 100 nm longer than those of the biphenyl derivatives formed with our previously developed fluorogenic derivatization method. Also, by the investigation using vinylbenzenes containing electron-donating or -withdrawing functional groups, it was found that an internal charge transfer system could contribute to extend the emission wavelength of the derivative. Furthermore, the proposed reaction was applied to develop a pre-column derivatization HPLC with fluorescence detection method for aryl bromides using 4-vinylanisole. p-Substituted aryl bromide derivatives (i.e., p-bromobenzonitrile, p-bromoanisole, bromobenzene, p-bromobenzoic acid ethyl ester, p-bromotoluene) were successfully detected within 40 min with the detection limit of 0.007 - 0.264 μM. Despite the short reaction time of 10 min, the reaction yields for p-bromoanisole and bromobenzene were good at 101 and 87%, respectively.

RE-p-halobenzoic acid–terpyridine complexes, Part II: structural diversity, supramolecular assembly, and luminescence properties in a series of p-bromobenzoic acid rare-earth hybrid materials

Twenty-four new rare-earth p-bromobenzoic acid complexes, [RE(L1)3(L2)(H2O)]2 (RE = La3+ (1), Ce3+ (2), Pr3+ (3), Nd3+ (4)), [RE(L1)3(L2)(H2O)]2 (RE = La3+ (1′), Ce3+ (2′), Pr3+ (3′), Nd3+ (4′)), [RE(L1)3(L2)]2·H2O (RE = Sm3+ (5), Eu3+ (6), Gd3+ (7), Tb3+ (8)), RE(L1)3(L2)(H2O) (RE = Gd3+ (7′), Tb3+ (8′), Dy3+ (9), Ho3+ (10), Er3+ (11), Tm3+ (12), Yb3+ (13), Lu3+ (14), Y3+ (15)), and RE2(L1)4(L2)2(Ox) (RE = Tm3+ (12′), Yb3+ (13′) Lu3+ (14′)); L1: p-bromobenzoic acid; L2: 2,2′:6′,2′′-terpyridine; Ox: oxalic acid, have been hydrothermally synthesized and structurally characterized by single crystal and powder X-ray diffraction. The series includes binuclear molecular complexes [(La3+–Nd3+), (La′3+–Nd′3+), (Sm3+–Tb3+)], which transition to pseudo-dimeric units (Gd3+–Y3+) as a result of the lanthanide contraction. The range of structures is completed by distinct oxalate-bridged binuclear complexes (Tm3+–Lu3+), formed via in situ synthesis, that appear only with the smallest lanthanides and only from higher temperature syntheses. There are subtle differences in coordination environments between the five structure types as a result of the lanthanide contraction, despite all complexes in this study containing binuclear units. All twenty-four complexes feature halogen- and π-based supramolecular interactions which assemble the molecular complexes into one, two, and three dimensions. Visible and near-IR solid state luminescence spectra were collected on complexes 3, 4, 5, 6, 8, 8′, 9, 12, and 13 and characteristic terpyridine sensitized luminescence was observed.

Preparation of a graphene oxide/silica composite modified with nitro-substituted tris(indolyl)methane as a solid-phase extraction sorbent for the extraction of organic acids.

This paper describes the use of graphene oxide/silica modified with nitro-substituted tris(indolyl)methane as a solid-phase extraction sorbent for the determination of organic acids. The resultant graphene oxide/silica modified with nitro-substituted tris(indolyl)methane was characterized by FTIR spectroscopy and adsorption experiments. Solid-phase extraction parameters such as sorbent type, sample solution pH, sample loading rate, eluent salt concentration, eluent methanol concentration, elution rate, sample loading, and elution volume were optimized. The method showed good precision, accuracy, sensitivity, and linear response for organic acids analysis over a concentration range of 1-100 μg/L for benzoic acid, p-methoxybenzoic acid, and salicylic acid and 5-100 μg/L for the remaining organic acids (cinnamic acid, p-chlorobenzoic acid, and p-bromobenzoic acid) with coefficients of determination (r(2) ) of higher than 0.9957. Limits of detection from 0.50 to 1.0 μg/L for six organic acids were achieved. The developed method was successfully applied to determine organic acids in real samples.

Chemistry and Spectroscopy of Renewable Materials, Part 1: Imaging the Penetration Depth of Covalent Wood Modification

The covalent modification of pine sapwood by benzotriazolyl activated benzoic acids offers broad access to new, durable functional materials. The penetration depth of these substituted benzoic acids remained unknown so far. Two independent proofs were received for the first time by parallel 3D-μCT imaging and attenuated total reflection infrared spectroscopy studies on approximately 10 × 10 × 10 mm wood cubes esterified with activated p-bromobenzoic acid. It proved feasible to penetrate pine sapwood anisotropically as deep as 4.5 (with the grain) to 0.75 mm (across the grain), depending on the orientation of the fibers. The results prove the usability of the applied modification procedure.

Aryl carboxylic acid reduction and further reactions with GABA and glucose promoted by whole cells of Xylaria arbuscula

Xylaria arbuscula was collected from a “Cypress” tree, Cupressus lusitanica. The whole cells of this endophytic fungus were used in screening for microbial bioreduction of aryl acids. Different p-substituted benzoic acids were evaluated. However, only p-bromobenzoic acid, p-chlorobenzoic acid and p-nitrobenzoic acid were converted to their corresponding alcohols. Aryl acid metabolism of X. arbuscula included GABA incorporation and glycosylation when the substrates were p-bromobenzoic and p-chlorobenzoic acids were also observed. The substrates p-hydroxybenzoic and p-aminobenzoic acids were not transformed. These results could suggest that electron-withdrawing groups at para orientation activate the substrate for reduction.

Synthesis, X-ray crystal structures and inclusion properties of a hydrogen-bonded coordination polymer [Ni(SCN)2(pppeH)2]·(guest)x

This study reports three inclusion compounds [Ni(SCN)2(pppeH)2]·(guest)x (1–3) and a guest-free crystal [Ni(SCN)2(pppeH)2] (4), where pppeH = trans-3-[4-(4-pyridyl)phenyl]propenoic acid and guest = dibenz[a,h]anthracene (x = 1/2) (1), p-bromobenzoic acid (x = 1) (2) and 4,4′-dibromobiphenyl (x = 1) (3). The crystal structures of 1–4 are best described as consisting of layers. The layer, [Ni(SCN)2(pppeH)2]∞, is formed by R22(8) O–H⋯O hydrogen bonding between the pppeH ligands coordinating to Ni2+ ions of adjacent 1D coordination polymers. The layers of 1–3 have cavities surrounded by two pppeH dimers and four μ-1,3-SCN ligands with the dimensions of ca. 25.5 × 6.2–7.6 A2. On the other hand, the layer of 4 does not. This indicates that the guests act as templates for the formation of the cavity. Interlayer connection of the cavities gives channels penetrating through the crystals where the guests are arranged one-dimensionally. Detailed investigation on the crystal structures of 1–3 and [Ni(SCN)2(pppeH)2]·(benz[a]anthracene)2/3 (5) reported previously has revealed that the stacking manner of the layers, the interlayer separation and the structure of the layer are adjusted in response to the guests, and simultaneously the guests adjust their positions and orientations to form a close-packed structure.

Synthesis, crystal structure and thermal decomposition mechanism of the complex [Sm(p-BrBA)3bipy·H2O]2·H2O

Abstract A new binuclear samarium (III) complex [Sm(p-BrBA)3bipy·H2O]2·H2O (p-BrBA = p-bromobenzoic acid; bipy = 2,2′-bipyridine) has been synthesized and characterized by elemental analysis, UV, IR, molar conductance and TG–DTG techniques. The structure of the complex was established by single crystal X-ray diffraction. It crystallizes in triclinic, space group P 1 ¯ with a = 8.2476(7) A, b = 13.3483(10) A, c = 15.9035(13) A, α = 73.9160(10)°, β = 78.9630(10)°, γ = 74.4770(10)°, Z = 1, Dc = 1.947 g cm−3, F(000) = 910. The carboxylic groups are bonded to the samarium ion in two modes: bidentate bridging, monodentate. Each center Sm3+ ion is eight-coordinated by one 2,2′-bipyridine molecular, four bidentate bridging and a monodentate carboxylic group, as well as one water molecular. The coordination polyhedron around each Sm3+ ion can be described as bi-capped triangular prism geometry. The thermal decomposition behavior of the title complex in a static air atmosphere was investigated by TG–DTG and IR techniques.

Optimization of a convenient route to produce N-succinimidyl 4-radiodobenzoate for radioiodination of proteins

The preparation of N-succinimidyl-4-[ 131I]iodobenzoate (SIB) has been optimized using an alternative technique employing Cu(I)-assisted radioiododebromination that produces p-[ 131I]iodobenzoic acid. The reaction conditions were optimized and radiochemical purity of more than 90% was obtained when using 160°C, 60 min reaction time and a [CuCl]/[ p-bromobenzoic acid] relation of about 10 −2. After purification, the p-[ 131I]iodobenzoic acid reacted with TSTU to produce the SIB in a radiochemical yield greater than 98%. Protein conjugation using SIB resulted in a relatively low radiochemical yield. Biological distribution studies evidenced the in vivo stability of the labeled protein.

Two-dimensional camera for millisecond range time-resolved small- and wide-angle X-ray scattering

A combined small-angle and wide-angle X-ray scattering (SAXS/WAXS) camera has been implemented using area detectors suitable for real time experiments down to millisecond time range. The design is based on the existing high brilliance SAXS camera with a sample-to-detector distance variable from 1 m to 10 m and to which a two-dimensional WAXS detector is coupled. Two independent image intensified CCD detectors allow simultaneous real-time SAXS/WAXS experiments on oriented samples down to the millisecond time range. A wide scattering vector range spanning from 0.001 Å-1 to 6 Å-1 is covered by this combined setup. Both detectors have single photon sensitivity and the spatial resolution is about 200 μm. The WAXS detector is mounted at an angle inclined to the primary beam and the process of image transformation into non-arbitrary scattering vector coordinates is demonstrated for a standard p-bromobenzoic acid sample.

Combustion calorimetry on samples of mass about 7 mg of substances containing bromine with a CRMT rocking-bomb calorimeter. Application to the study of p-bromobenzoic acid

Wishing to extend its possibilities, we have used a CRMT rocking calorimeter associated with a microbomb to determine the enthalpy of combustion of a sample of low mass (about 7 mg) of a substance containing bromine. p-Bromobenzoic acid, p-BrC 6H 4COOH, a candidate as reference material for combustion calorimetry of substances containing bromine, has been investigated. The value of −(3090.1 ± 1.3)kJ ·mol −1for its molar enthalpy of combustion obtained with this apparatus is in very good agreement with the two literature values obtained by classical rotating-bomb combustion calorimetry ( m≈ 1 g for each combustion).

Simultaneous inversion of configuration of both the chiral ring and the carbinol carbon in (E)-(1 R,2R)-cyclo-oct-2-en-1-ol

The reaction of (–)-(E)-(1 R,2R)-cyclo-oct-2-en-1-ol with p-bromobenzoic acid under Mitsunobu reaction conditions yields the corresponding p-bromobenzoate with simultaneous inversion of configuration of both the chiral ring and the carbinol carbon.

Infrared Multiple Specular Reflectance of Mono- and Submonomolecular Layers of p-Bromobenzoic Acid on Oxidized Metals

The advantages of Multiple Specular Reflection (MSR) over single reflection grazing incidence infrared spectroscopy are discussed in this paper. A calculation which incorporates the experimental constraints for a multiple reflection setup is performed. The results concerning the angular dependence are confirmed by experiment. The main advantages are a wide angular acceptance and a release of the grazing angle of incidence geometry. Approximately the same sensitivity can be obtained as is theoretically possible with a single reflection at grazing incidence. However, in practice a somewhat higher sensitivity can be obtained with multiple specular reflectance spectroscopy. The sensitivity is illustrated by the measurement of submonolayers of p-bromobenzoic acid chemi-sorbed on an oxidized aluminium flat surface. Comparison with neutron activation analysis data shows that the reflection-absorption intensities are proportional to the surface coverage. A dependence of spectral features on surface coverage can be observed.

ChemInform Abstract: THE CRYSTAL STRUCTURE OF P‐IODOBENZOIC ACID INVESTIGATED BY X‐RAY POWDER DIFFRACTION

The crystal of the title compound is monoclinic with space group P21/a, a=30.36(3), b=6.04(1), c=4.16(1) A, β=97.4(1)° and Z=4. The crystal structure was solved from X-ray powder diffractometer data by the packing analysis based on an ellipsoid-model and by the pattern-fitting structure refinement. The final R (profile) value was 0.168. This structure is isostructural with that of p-bromobenzoic acid.

Aromatic radiobromination without added carrier

p-Bromo-N,N-dimethylaniline, bromobenzene, and p-bromobenzoic acid labelled with 77Br or 80mBr have been prepared by radiobromodestannylation at no-carrier-added levels of radiobromine.

The Crystal Structure of p-Iodobenzoic Acid Investigated by X-Ray Powder Diffraction

Abstract The crystal of the title compound is monoclinic with space group P21/a, a=30.36(3), b=6.04(1), c=4.16(1) Å, β=97.4(1)° and Z=4. The crystal structure was solved from X-ray powder diffractometer data by the packing analysis based on an ellipsoid-model and by the pattern-fitting structure refinement. The final R (profile) value was 0.168. This structure is isostructural with that of p-bromobenzoic acid.

The crystal and molecular structures of the 1:1 addition compounds of piperidine with p-bromobenzoic acid and p-chlorobenzoic acid

The crystal and molecular structures of the 1:1 addition compounds of piperidine with p-bromobenzoic acid and p-chlorobenzoic acid

The Effects of Paba Derivatives on the Multiplication of Typhus Rickettsiae

Summary and Conclusions The rickettsiostatic activity of 1) isosteres of PABA, 2) p-halobenzoic acids, 3) p-alkoxybenzoic acids and 4) compounds with substitutions in the carboxyl group of PABA were determined. The compounds were titrated to an upper limit which was toxic to the embryo or inhibitory to the growth of rickettsiae and to a lower limit which was non-inhibitory to the growth of rick-ettsiae. PABA and its isosteres showed the following order of activity: p-aminobenzoic acid τ; p-methylbenzoic acid τ; p-fluorobenzoic acid. p-Hydroxybenzoic acid did not exhibit rickettsiostatic activity. The order of rickettsiostatic activity of the p-halobenzoic acids was: p-iodobenzoic acid τ; p-bromobenzoic acid τ; p-chlorobenzoic acid τ; p-fluorobenzoic acid. The rickettsiostatic activity of the effective p-alkoxybenzoic acids increased directly as the length of the carbon chain: p-pentoxy benzoic acid τ; p-propoxybenzoic acid τ; p-ethoxybenzoic acid τ; p-methoxybenzoic acid. p-Butoxy-benzoic acid was not active. p-Aminohippuric acid partially inhibited the growth of rickettsiae. Other compounds containing carboxyl group substitutions (p-aminoacetophenone and p-aminopropiophenone, and methyl-p-aminobenzoate) were very toxic to the embryos and did not inhibit rickettsiostatic activity when given in tolerated doses.