Benzoic Acid Side Research Articles

Polarized Fluorescence of N-Salicylideneaniline Derivatives Formed by In Situ Exchange from N-Benzylideneaniline Side Groups in Photoaligned Liquid Crystalline Copolymer Films.

Polarized fluorescence of oriented N-salicylideneaniline (SA) derivatives is explored based on the thermally stimulated photoinduced molecular reorientation of liquid crystalline (LC) copolymethacrylate with N-benzylideneaniline derivative (NBA2) and benzoic acid (BA) side groups. The LC copolymer films show significant cooperative molecular reorientation of the NBA2 and BA side groups (D > 0.7). Subsequent thermal hydrolysis of the NBA2 side groups yields free phenylamine moieties. These moieties can form oriented SA derivatives via in situ condensation with 2-hydroxybenzaldehyde derivatives. The excited-state intermolecular proton transfer of the oriented SA molecules induces polarized fluorescence at 510-548 nm with a polarization ratio up to 6.2. Direct in situ exchange from the oriented NBA2 to SA derivatives achieves polarized fluorescence similar to that of the SA side groups.

Host-guest chemistry of the sulfasalazine-β-cyclodextrin inclusion complex

Sulfasalazine (SLZ) is an azo drug used for the treatment of rheumatoid arthritis and ulcerative colitis. Its limited water solubility results into low permeability and bioavailability leading to higher daily recommended doses and greater side effects. Host-guest complexation of drugs with β-cyclodextrin (β-CD) is a common strategy to improve oral bioavailability and drug delivery. Traditional studies of inclusion complexes between SLZ and β-CD have been merely limited to UV analysis. We present herein, several structural evidences describing the detailed molecular architecture and binding constant of the inclusion complex using 1H NMR spectroscopy, isothermal titration calorimetry, ATR-IR spectroscopy, thermogravimetric analysis, and molecular modelling. Both 1H NMR and ITC methods converged toward closed values of Ka 1175 and 1220 M−1, respectively for the SLZ-β-CD inclusion complex. The modelling experiments also helped supporting the relative orientation of the SLZ into β-CD. The analysis revealed that SLZ integrates to β-CD exclusively from the benzoic acid end group and not through the pyridine moiety which is otherwise precluded because of its tilted structure that formed steric hindrance with the β-CD group. In addition, immobilization of SLZ through its benzoic acid side on CM5 sensor chip using surface plasmon resonance spectroscopy completely impeded the inclusion complex formation with β-CD. This comprehensive study of SLZ inclusion complexation with β-CD allows envisaging alternative strategies to improve SLZ solubility, bioavailability, and permeability for therapeutic applications.

Replication of Sequence Information in Synthetic Oligomers.

ConspectusThe holy grail identified by Orgel in his 1995 Account was the development of novel chemical systems that evolve using reactions in which replication and information transfer occur together. There has been some success in the adaption of nucleic acids to make artificial analogues and in templating oligomerization reactions to form synthetic homopolymers, but replication of sequence information in synthetic polymers remains a major unsolved problem. In this Account, we describe our efforts in this direction based on a covalent base-pairing strategy to transfer sequence information between a parent template and a daughter copy. Oligotriazoles, which carry information as a sequence of phenol and benzoic acid side chains, have been prepared from bifunctional monomers equipped with an azide and an alkyne. Formation of esters between phenols and benzoic acids is used as the equivalent of nucleic base pairing to covalently attach monomer building blocks to a template oligomer. Sequential protection of the phenol side chains on the template, ester coupling of the benzoic acid side chains, and deprotection and ester coupling of the phenol side chains allow quantitative selective base-pair formation on a mixed sequence template. Copper catalyzed azide alkyne cycloaddition (CuAAC) is then used to oligomerize the monomers on the template. Finally, cleavage of the ester base pairs in the product duplex by hydrolysis releases the copy strand. This covalent template-directed synthesis strategy has been successfully used to copy the information encoded in a trimer template into a sequence-complementary oligomer in high yield.The use of covalent base pairing provides opportunities to manipulate the nature of the information transferred in the replication process. By using traceless linkers to connect the phenol and benzoic acid units, it is possible to carry out direct replication, reciprocal replication, and mutation. These preliminary results are promising, and methods have been developed to eliminate some of the side reactions that compete with the CuAAC process that zips up the duplex. In situ end-capping of the copy strand was found to be an effective general method for blocking intermolecular reactions between product duplexes. By selecting an appropriate concentration of an external capping agent, it is also possible to intercept macrocyclization of the reactive chain ends in the product duplex. The other side reaction observed is miscoupling of monomer units that are not attached to adjacent sites on the template, and optimization is required to eliminate these reactions. We are still some way from an evolvable synthetic polymer, but the chemical approach to molecular replication outlined here has some promise.

Photoinduced Reorientation and Photofunctional Control of Liquid Crystalline Copolymers with in Situ-Formed N-Benzylideneaniline Derivative Side Groups.

The influence of the annealing conditions on the thermally stimulated photoinduced molecular reorientation of a photoinactive liquid crystalline polymethacrylate with phenyl aldehyde and benzoic acid side groups (P1) doped with 4-methoxyaniline, which forms photoalignable 4-methoxy-N-benzylideneaniline (MNBA) side groups in situ, was investigated. Light exposure and subsequent thermal stimulation under a N2 atmosphere realized sufficient cooperative molecular reorientation (D > 0.7), but the simultaneous thermal hydrolysis of the MNBA groups under humid air lowered the molecular reorientation performance. By contrast, subsequent thermal hydrolysis of MNBA after molecular reorientation introduced different aromatic amines into the reoriented P1 film, which regulated the birefringence and photofunctionality of the oriented film.

Influence of alkylene spacer length on the photoinduced reorientation of polymethacrylate with benzoic acid side groups and N-benzylideneaniline carboxylic acid composite films

Photoinduced reorientation of composite films of liquid crystalline polymethacrylate comprised of benzoic acid (BA) side groups with different length alkylene spacer (PnBAM; n = 2, 6, 10) and N-benzylideneaniline carboxylic acid (NBA) is investigated using linearly polarized (LP) 365 nm light. Significant thermally stimulated in-plane molecular orientation is attained when P6BAM (n = 6) is used, but higher amount of NBA is required for the in-plane reorientation of P2BAM (n = 2) films and out-of-plane motion of the BA side groups is observed for P10BAM (n = 10) films.

Photoinduced Reorientation and Surface Relief Formation in Diblock and Random Copolymers with Benzoic Acid and Alkyloxy Side Groups

Diblock and random copolymers are synthesized from a methacrylate with benzoic acid (BA) side groups and a n-butyl methacrylate, and the photoinduced reorientation of thin films doped with a N-benzylideneaniline carboxylic acid (NBA), which governs the H-bond with BA, is investigated using linearly polarized (LP) 365 and 313 nm light. A sufficient thermally stimulated photoinduced orientation of the BA side groups and simultaneous sublimation of NBA are attained for the diblock copolymer films, whereas a thermal treatment results in the random orientation of the random copolymers. Furthermore, surface relief (SR) formation of the film is explored when the NBA-doped films are exposed to LP light using a photomask. The liquid crystalline characteristics, thermal properties, axis-selective photoisomerization, and the photo-cross-linking of the film play important roles in the molecular reorientation and SR formations.

Photoinduced Birefringent Pattern and Photoinactivation of Liquid-Crystalline Copolymer Films with Benzoic Acid and Phenylaldehyde Side Groups.

In situ formation of N-benzylideneaniline (NBA) side groups achieved photoinduced cooperative reorientation of photoinactive copolymers with phenylaldehyde (PA) and benzoic acid (BA) side groups doped with 4-methoxyaniline (AN) molecules. Thermally stimulated molecular reorientation of the side groups was generated due to the axis-selective photoreaction of the NBA moieties. Selective coating with AN on the copolymer film formed NBA moieties in the desired region, resulting in a photoinduced birefringent pattern. Additionally, postannealing at an elevated temperature for a long time attained photoinactivation of the reoriented film, and recoating with AN to form NBA achieved the multiple birefringent patterns and repatterning of the reoriented structures. The slow thermal hydrolysis of NBA, which was 50 times slower than the thermally stimulated self-organization of the side groups due to the presence of BA side groups, contributed to the photodurability of the reoriented film and multiple birefringent patterns.

Birefringent Pattern Formation in Photoinactive Liquid Crystalline Polymer Films Based on a Photoalignment Technique with Top-Coating of Cinnamic Acid Derivatives via H-Bonds.

The application of a top-coating of 4-methoxy cinnamic acid (MCA) onto a photoinactive liquid crystalline polymeric film containing benzoic acid (BA) side groups (P6BAM) is shown to enable thermally stimulated, photoinduced reorientation of the polymer structure. Annealing the MCA-coated P6BAM films leads to H-bond formation between BA and MCA, which also effectively smooths the film surface. Exposure to linearly polarized (LP) UV light initiates axis-selective photoreaction of the MCA groups; subsequent thermal treatment in the LC temperature range of P6BAM amplifies molecular reorientation of the BA side groups, while simultaneously eliminating the MCA molecules. Selective inkjet coating of MCA provides a facile route for the fabrication of patterned, oriented, and rewritable P6BAM films with multiple controlled alignment directions.

Photoinduced orientation of H-bonded composite films of non-photoreactive polymer and cinnamic acid derivatives

ABSTRACTThis paper describes the thermally amplified photoinduced orientation behavior of H-bonded composite thin films of non-photoreactive polymethacrylate consisting of hexylene spacer groups terminated with benzoic acid (BA) moieties in the side chain (pM6BA) and various monomeric cinnamic acid (CA) derivatives. H-bonds between BAs and CAs cause all the pM6BA/CA derivatives composite films to exhibit liquid crystalline characteristics. Irradiating these films with linearly polarized UV light induces an axis-selective photoreaction of the CA derivatives, while subsequent thermal treatment induces molecular reorientation of the BA side groups, which is accompanied by sublimation of the unreacted CA derivatives. The reoriented films are applicable to an LC alignment layer.

Fabrication of UV-inactive photoaligned films by photoinduced orientation of H-bonded composites of non-photoreactive polymer and cinnamate derivative

We explored the fabrication of ultraviolet (UV)-inactive photoaligned film by photoinduced orientation of H-bonded composites of non-photoreactive polymethacrylate consisting of hexylene spacer groups terminated with a benzoic acid (BA) moiety in its side chain (pM6BA) and low-molecular 4-methoxycinnamic acid (4MCA). The pM6BA/4MCA composite films exhibit liquid crystal characteristics owing to the presence of H-bonds between BA and 4MCA as well as between the BA groups. Exposure to linearly polarized UV light gives rise to axis-selective photoreaction of the 4MCAs, while thermal treatment induces the molecular reorientation of the BA side groups accompanied by the sublimation of unreacted 4MCA. As a result, the reoriented film is durable with respect to UV light irradiation, which may be useful for display applications. Photoinduced orientation of H-bonded composites of non-photoreactive polymethacrylate consisting of a benzoic acid (BA) moiety (pM6BA) and 4-methoxycinnamic acid (4MCA) is investigated. The pM6BA/4MCA composite films exhibit liquid crystal characteristics owing to H-bonds between BA and 4MCA as well as between the BA groups. Exposure to linearly polarized UV light gives rise to axis-selective photoreaction of the 4MCAs, while thermal treatment induces the molecular reorientation of the BA side groups accompanied by the sublimation of unreacted 4MCA.

Thermal Amplification of Photoinduced Cooperative Reorientation of Liquid Crystalline Copolymer Films Comprised of N-Benzylideneaniline and Benzoic Acid Side Groups

This paper describes photoinduced cooperative molecular reorientation and its thermally stimulated amplification in liquid crystalline copolymethacrylates (LCPs) with hexamethylene spacer groups terminated with N-benzylideneaniline (NBA) and benzoic acid (BA) in the side chain. Influence of the copolymerization ratio and annealing temperature on the molecular reorientation behavior is investigated. Both NBA and BA side groups cooperatively reorient, but the orientation order depends on the copolymerization ratio. In contrast, sufficient thermal amplification of the photoinduced optical anisotropy is achieved for all LCPs, which is controlled by adjusting the annealing temperature.

Photoinduced Cooperative Orientation and Pattern Formation in Copolymer Films with 4-Methoyazobenzene and Benzoic Acid Side Groups

Photoinduced cooperative molecular reorientation in liquid crystalline (LC) methacrylate copolymers with hexamethylene spacer groups terminated with 4-methoxyazobenzene and benzoic acid in the side chain, and the influence of the copolymerization ratio on the thermally enhanced photoinduced molecular reorientation behavior were investigated. All copolymers exhibited a LC phase, and sufficient thermally enhanced photoinduced in-plane molecular reorientation was achieved by irradiating with linearly polarized (LP) UV light and subsequent annealing when the azobenzene composition was greater than 5 mol%. Adjusting the exposure energy and the polarization of the LPUV light attained a patterned oriented structure, which can be useful as alignment layer for functional materials. Finally, a patterned birefringent film was fabricated using photocurable liquid crystals on the patterned copolymer film.

Synthesis of (bis)Sulfonic acid, (bis)Benzamides as follicle-Stimulating hormone (FSH) antagonists

Screening efforts identified (bis)sulfonic acid, (bis)benzamides ( 1– 3) as compounds that interact with the follicle stimulating-hormone receptor (FSHR) and inhibit FSH-stimulated cAMP accumulation with IC 50 values in the low micromolar range. Structure–activity relationship studies using novel analogues of 1– 3 revealed that two phenylsulfonic acid moieties were necessary for activity and that the carbon–carbon double bond of the stilbene sub-series was the optimum spacer connecting these groups. Selected analogues ( 2, 14, and 50) were also able to block FSHR-dependent estradiol production in rat primary ovarian granulosa cells and progesterone secretion in a clonal mouse adrenal Y1 cell line. IC 50 values for these compounds in these assays were in the low micromolar range. Optimization of the benzoic acid side chains of 1– 3 led to gains in selectivity versus activity at the thyroid stimulating hormone (TSH) receptor (TSHR). For instance, while stilbene (bis)sulfonic acid congener 2 was only 10-fold selective for FSHR over TSHR, analogue 50 with an IC 50 value of 0.9 μM in the FSHR-cAMP assay was essentially inactive at 30 μM in the TSHR-cAMP assay.