Phthalamic Acid Research Articles

ChemInform Abstract: Synthesis of a Novel Water Soluble Phthalimide Derivative of Acetaminophen as Potential Analgesic and Antipyretic Agent.

A short process for the preparation of water soluble, potential analgesic compound, N-[(4-hydroxy-phenylcarbamoyl)-methyl]phthalamic acid 4 has been developed. Two synthetic routes (A and B) have been established for the preparation of 2-(1,3-dioxo1,3-dihydro-isoindol-2-yl)-N-(4-hydroxyphenyl)acetamide 3. In route A, 4-aminophenol 5 is reacted with chloroacetyl chloride 6 in solution of potassium acetate and acetic acid at 0-5°C to yield N-(4-hydroxyphenyl)-2-chloroacetamide 7. The latter is reacted with potassium phthalimide 8 and KI in DMF at 130°C to give 3. Alternatively, in route B, reaction of phthalic anhydride 8 with glycine 9 at 150°C yields the acid intermediate (1,3-dioxo-1,3dihydro-isoindol-2-yl)-acetic acid 11, which on reaction with 4aminophenol 6 in DMF and in the presence of dicyclohexylcarbodimide gives 3. The latter is hydrolysed in ethanolic KOH to afford 4.

Identification of dehydrocostus lactone and 4-hydroxy-β-thujone as auxin polar transport inhibitors

The survey of naturally occurring of auxin polar transport regulators in Asteraceae was investigated using the radish (Raphanus sativus L.) hypocotyl bioassay established in this study. Significant auxin polar transport was observed when radiolabeled indole-3-acetic acid (IAA) was applied at the apical side of radish hypocotyl segments, but not when it was applied at the basal side of the segments. Almost no auxin polar transport was observed in radish hypocotyl segments treated with synthetic auxin polar transport inhibitors of N-(1-naphthyl)phthalamic acid (NPA) and 9-hydroxyfluorene-9-carboxylic acid (HFCA) at 0.5 μg/plant. 2,3,5-Triiodobenzoic acid (TIBA) at 0.5 μg/plant was less effective than NPA and HFCA, and p-chlorophenoxyisobutyric acid (PCIB) at 0.5 μg/plant had almost no effect on auxin polar transport in the radish hypocotyl bioassay. These results strongly suggest that the radish hypocotyl bioassay is suitable for the detection of bioassay-derived auxin polar transport regulators. Using the radish hypocotyl bioassay and physicochemical analyses, dehydrocostus lactone (decahydro-3,6,9-tris-methylene-azulenol(4,5-b)furan-2(3H)-one) and 4-hydroxy-β-thujone (4-hydroxy-4-methyl-1-(1-methylethyl)-bicyclo[3.1.0]hexan-3-one) were successfully identified as auxin polar transport inhibitors from Saussurea costus and Arctium lappa, and Artemisia absinthium, respectively. About 50 and 40 % inhibitions of auxin polar transport in radish hypocotyl segments were observed at 2.5 μg/plant pre-treatment (see “Materials and methods”) of dehydrocostus lactone and 4-hydroxy-β-thujone, respectively. Although the mode of action of these compounds in inhibiting auxin polar transport has not been clear yet, their possible mechanisms are discussed.

A Facile and Green Synthesis of Novel Imide and Amidic Acid Derivatives of Phenacetin as Potential Analgesic and Anti-Pyretic Agents

Facile and green syntheses of potential analgesic and antipyretic compounds, N-(4-ethoxy-phenyl)-2-(1,3- dioxo-1,3-dihydroisoindol-2-yl)acetamide derivatives 6a-g and N-[(4-ethoxy-phenylcarbamoyl)methyl]phthalamic acid derivatives 10a-g have been developed. Two synthetic routes (A and B) have been established for the preparation of 6a-g. In the route-A, 4-ethoxyaniline 2 was reacted with chloroacetyl chloride 3 in a solution of potassium acetate and acetic acid to yield N-(4-ethoxyphenyl)-2-chloroacetamide 4. The latter was reacted with imide compounds 5a-g either in triethanolamine as a green solvent or in solid phase in the presence of TEBAC and KI to yield 6a-g. Alternatively, in the route-B, reaction of anhydrides 7a-g with glycine 8 yielded the (1, 3-dioxo-1, 3-dihydroisoindol-2-yl)acetic acid derivatives 9a-g which on reaction with 2 either in triethnolamine and DCC as a dehydrating agent or in solid phase in the presence of DCC gave 6a-g. The latter were hydrolyzed in 0.5N ethanolic KOH to afford 10a-g. Keywords: Anhydrides, imides, 4-ethoxyaniline, phenacetin, Analgesic & Antipyretic, erythrocytes, triethanolamine, TEBAC, Perkin – Elmer 1000, capillary tubes, structural

Morphactin Substantially Induced the Fourth Internode Growth in Decapitated Tulips: Relevance to Endogenous Levels of Indole-3-Acetic Acid

Abstract Important role of auxin polar transport inhibitors such as TIBA (2,3,5- triiodobenzoic acid), NPA (N-(1-naphthyl)phthalamic acid) and morphactin (methyl 2-chloro-9-hydroxyfluorene-9-carboxylate) in stem growth of tulips was intensively studied. After the application of morphactin above the 3rd node of decapitated tulips, the stimulated growth of the 4th internode was clearly observed. On the other hand, NPA and TIBA were slightly effective in stimulating the 4th internode growth of tulips. Endogenous levels of IAA in the 4th internode after the treatment of auxin polar transport inhibitors were determined using gas-liquid chromatography-mass spectrometry (GC-MS) and gas-liquid chromatography-mass spectrometry selected ion monitoring system (GC-SIM) with deuterium labelled IAA (Indole-2,4,5,6,7-d5-3- acetic acid, d5-IAA) as an internal standard, resulted in significant accumulation of IAA in the 4th internode of tulips after the treatment of morphactin. In the treatment of NPA and TIBA, there was almost no such an accumulation of IAA. These results strongly suggest that stimulated growth of the 4th internode of tulips induced by the application of morphactin is the consequence of accumulated endogenous levels of IAA after the treatment. The possible mode of action of auxin polar transport inhibitors in tulip stem growth is also discussed.

Toxicokinetic modeling of folpet fungicide and its ring‐biomarkers of exposure in humans

A human in vivo toxicokinetic model was built to allow a better understanding of the toxicokinetics of folpet fungicide and its key ring biomarkers of exposure: phthalimide (PI), phthalamic acid (PAA) and phthalic acid (PA). Both PI and the sum of ring metabolites, expressed as PA equivalents (PAeq), may be used as biomarkers of exposure. The conceptual representation of the model was based on the analysis of the time course of these biomarkers in volunteers orally and dermally exposed to folpet. In the model, compartments were also used to represent the body burden of folpet and experimentally relevant PI, PAA and PA ring metabolites in blood and in key tissues as well as in excreta, hence urinary and feces. The time evolution of these biomarkers in each compartment of the model was then mathematically described by a system of coupled differential equations. The mathematical parameters of the model were then determined from best fits to the time courses of PI and PAeq in blood and urine of five volunteers administered orally 1 mg kg(-1) and dermally 10 mg kg(-1) of folpet. In the case of oral administration, the mean elimination half-life of PI from blood (through feces, urine or metabolism) was found to be 39.9 h as compared with 28.0 h for PAeq. In the case of a dermal application, mean elimination half-life of PI and PAeq was estimated to be 34.3 and 29.3 h, respectively. The average final fractions of administered dose recovered in urine as PI over the 0-96 h period were 0.030 and 0.002%, for oral and dermal exposure, respectively. Corresponding values for PAeq were 24.5 and 1.83%, respectively. Finally, the average clearance rate of PI from blood calculated from the oral and dermal data was 0.09 ± 0.03 and 0.13 ± 0.05 ml h(-1) while the volume of distribution was 4.30 ± 1.12 and 6.05 ± 2.22 l, respectively. It was not possible to obtain the corresponding values from PAeq data owing to the lack of blood time course data.

Pseudonodule Formation by Wild-Type and Symbiotic Mutant Medicago truncatula in Response to Auxin Transport Inhibitors

Rhizobium and allied bacteria form symbiotic nitrogen-fixing nodules on legume roots. Plant hormones play key roles in nodule formation. We treated Medicago truncatula roots with auxin transport inhibitors (ATI) N-(1-naphthyl)phthalamic acid (NPA) and 2,3,5-triiodobenzoic acid (TIBA) to induce the formation of pseudonodules. M. truncatula mutants defective for rhizobial Nod factor signal transduction still formed pseudonodules in response to ATI. However, a M. truncatula ethylene-insensitive supernodulator, sickle 1-1, did not form pseudonodules in response to TIBA, suggesting that the ethylene response pathway is involved in ATI-induced pseudonodule formation. We compared the transcriptional responses of M. truncatula roots treated with ATI to roots inoculated with Sinorhizobium meliloti. Some genes showed consistently parallel expression in ATI-induced and Rhizobium-induced nodules. For other genes, the transcriptional response of M. truncatula roots 1 and 7 days after ATI treatment was in the opposite direction to roots treated with S. meliloti; then, by 21 days, the transcriptional patterns for the two conditions became similar. We silenced 17 genes that were upregulated in both ATI and S. meliloti treatments to determine their effect on nodule formation. Some gene-silenced roots showed a decrease in nodulation efficiency, suggesting a role in nodule formation but not in later nodule functions.

Synthesis of New Schiff's Bases Derived from 4-Phthalimidyl Acetophenone

Eight new Schiff's bases were prepared in three steps. The first step includes synthesis of phthalamic acid from the reaction between phthalic anhydride with p-amino acetophenone which in turn fused in the second step to form the corresponding phthalimide. The third step involved condensation of the prepared phthalimide with different primary aromatic amines to form new Schiff's bases. These compounds were characterized by FT-IR, 1 H-NMR and 13 C-NMR spectroscopy. Most of the synthesized compounds have been screened for their antimicrobial activities by using agar cup plate method against two types of bacteria .The results showed that the new Schiff's bases exhibit good to moderate antibacterial activity.

Gas-chromatography mass-spectrometry determination of phthalic acid in human urine as a biomarker of folpet exposure

Agricultural workers are exposed to folpet, but biomonitoring data are limited. Phthalimide (PI), phthalamic acid (PAA), and phthalic acid (PA) are the ring metabolites of this fungicide according to animal studies, but they have not yet been measured in human urine as metabolites of folpet, only PA as a metabolite of phthalates. The objective of this study was thus to develop a reliable gas chromatography-tandem mass spectrometry (GC-MS) method to quantify the sum of PI, PAA, and PA ring-metabolites of folpet in human urine. Briefly, the method consisted of adding p-methylhippuric acid as an internal standard, performing an acid hydrolysis at 100°C to convert ring-metabolites into PA, purifying samples by ethyl acetate extraction, and derivatizing with N,O-bis(trimethylsilyl)trifluoro acetamide prior to GC-MS analysis. The method had a detection limit of 60.2nmol/L (10ng/mL); it was found to be accurate (mean recovery, 97%), precise (inter- and intra-day percentage relative standard deviations <13%), and with a good linearity (R (2) > 0.98). Validation was conducted using unexposed peoples urine spiked at concentrations ranging from 4.0 to 16.1μmol/L, along with urine samples of volunteers dosed with folpet, and of exposed workers. The method proved to be (1) suitable and accurate to determine the kinetic profile of PA equivalents in the urine of volunteers orally and dermally administered folpet and (2) relevant for the biomonitoring of exposure in workers.

Changes in auxin distribution patterns during lateral root development in rice

Root differentiation in plants is mediated by the hormone auxin. As auxin is implicated in coordinating the development and organization of tissues in lateral roots, we investigated the inferred cellular distribution of auxin in various cell types in root prior to and during lateral root formation in rice ( Oryza sativa cv. Murasaki R86) using the transgenic plants carrying the auxin responsive soybean GH3 promoter fused to gusA. Modulation in the expression of the Pr GH3:gusA fusion was assessed by histological GUS staining in rice tissues following the treatment of transgenic rice seedlings with or without auxins such as 2,4-dichlorophenoxyacetic acid (2,4-D) or N-naphthaleneacetic acid (NAA), and the auxin transport inhibitors N-(1-naphthyl)phthalamic acid (NPA), kaempferol, quercetin, apigenin or Nod factors under axenic conditions. In this work we demonstrate that soybean GH3 promoter is active in rice, and the GH3-gusA reporter system can be utilized as a molecular marker to monitor the changes in auxin levels during organogenesis of this monocot plant. Our studies revealed distinct patterns of GH3 activity prior to and during various developmental phases of lateral root differentiation in rice. The GH3 expression patterns during lateral root development in rice showed considerable similarities with those occurring during comparable stages of lateral root development in dicots, implying that the requirement of auxin for the morphogenesis of lateral roots is similar in evolutionarily distinct monocots and dicots.

Dynamic, auxin-responsive plasma membrane-to-nucleus movement ofArabidopsisBRX

In Arabidopsis, interplay between nuclear auxin perception and trans-cellular polar auxin transport determines the transcriptional auxin response. In brevis radix (brx) mutants, this response is impaired, probably indirectly because of disturbed crosstalk between the auxin and brassinosteroid pathways. Here we provide evidence that BRX protein is plasma membrane-associated, but translocates to the nucleus upon auxin treatment to modulate cellular growth, possibly in conjunction with NGATHA class B3 domain-type transcription factors. Application of the polar auxin transport inhibitor naphthalene phthalamic acid (NPA) resulted in increased BRX abundance at the plasma membrane. Thus, nuclear translocation of BRX could depend on cellular auxin concentration or on auxin flux. Supporting this idea, NPA treatment of wild-type roots phenocopied the brx root meristem phenotype. Moreover, BRX is constitutively turned over by the proteasome pathway in the nucleus. However, a stabilized C-terminal BRX fragment significantly rescued the brx root growth phenotype and triggered a hypocotyl gain-of-function phenotype, similar to strong overexpressors of full length BRX. Therefore, although BRX activity is required in the nucleus, excess activity interferes with normal development. Finally, similar to the PIN-FORMED 1 (PIN1) auxin efflux carrier, BRX is polarly localized in vascular cells and subject to endocytic recycling. Expression of BRX under control of the PIN1 promoter fully rescued the brx short root phenotype, suggesting that the two genes act in the same tissues. Collectively, our results suggest that BRX might provide a contextual readout to synchronize cellular growth with the auxin concentration gradient across the root tip.

Kinetics and mechanism of hydrolysis of N‐(2′‐hydroxyphenyl)phthalamic acid (1) and N‐(2′‐methoxyphenyl)phthalamic Acid (2) in a highly alkaline medium

AbstractA kinetic study on hydrolysis of N‐(2′‐hydroxyphenyl)phthalamic acid (1), N‐(2′‐methoxyphenyl)phthalamic acid (2), and N‐(2′‐methoxyphenyl)benzamide (3) under a highly alkaline medium gives second‐order rate constants, kOH, for the reactions of HO− with 1, 2, and 3 as (4.73 ± 0.36) × 10−8 at 35°C, (2.42 ± 0.28) × 10−6 and (5.94 ± 0.23) × 10−5 M−1 s−1 at 65°C, respectively. Similar values of kOH for 3, N‐methylbenzanilide, N‐methylbenzamide, and N,N‐dimethylbenzamide despite the difference between pKa values of aniline and ammonia of ∼10 pK units are qualitatively explained. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 41: 1–11, 2009

ChemInform Abstract: Preparation of Phthalamic Acid Derivatives and Ring Closure to Phthalimidobarbituric Acids.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Quantification methods of folpet degradation products in plasma with HPLC-UV/DAD: Application to an in vivo toxicokinetic study in rats

Solid-phase extractions followed by HPLC-UV/DAD methods were developed for occupational biological monitoring or forensic investigations of the fungicide folpet using its degradation products, phthalimide and phthalamic acid as plasma biomarkers. These methods show good linearity ( r > 0.9955), precision (CV < 15%) and accuracy (bias < 14.8%). The lower limits of quantification for phthalimide and phthalamic acid were 10 and 20 ng/ml and the absolute recoveries were higher than 86% and 68%, respectively. Applying these methods, a plasma toxicokinetic study of folpet in rats after intratracheal administration of Folpan 80WG ® showed that inhalation of folpet could be a route of exposure with an important systemic absorption.

Preparation of phthalamic acid derivatives and ring closure to phthalimidobarbituric acids

Abstractmagnified imagePhthalamic acid derivatives with a barbiturate moiety were prepared from 5‐amino‐5‐ethylbarbituric acids. To circumvent an undesired acetylation in glacial acetic acid during the preparation of phthalimidobarbituric acids, two routes were proven exemplarily. On the one hand, a phthalamic acid (6a) was isolated and subsequently cyclized with acetic anhydride to the corresponding phthalimide 2a. On the other hand, a phthalamic acid tert‐butyl ester (5b) was successively treated with trifluoroacetic acid and trifluoroacetic anhydride to achieve heterocyclization to the phthalimide 2b. These routes might be useful for the preparation of other phthalimides derived from sterically hindered primary amines.

Differential regulation of Ku gene expression in etiolated mung bean hypocotyls by auxins

Plant Ku genes were identified very recently in Arabidopsis thaliana, and their roles in repair of double-stranded break DNA and maintenance of telomere integrity were scrutinized. In this study, the cDNAs encoding Ku70 ( VrKu70) and Ku80 ( VrKu80) were isolated from mung bean ( Vigna radiata L.) hypocotyls. Both genes were expressed widely among different tissues of mung bean with the highest levels in hypocotyls and leaves. The VrKu gene expression was stimulated by exogenous auxins in a concentration- and time-dependent manner. The stimulation could be abolished by auxin transport inhibitors, N-(1-naphthyl) phthalamic acid and 2,3,5-triiodobenzoic acid implicating that exogenous auxins triggered the effects following their uptake by the cells. Further analysis using specific inhibitors of auxin signaling showed that the stimulation of VrKu expression by 2,4-dichlorophenoxyacetic acid (2,4-D) was suppressed by intracellular Ca 2+ chelators, calmodulin antagonists, and calcium/calmodulin dependent protein kinase inhibitors, suggesting the involvement of calmodulin in the signaling pathway. On the other hand, exogenous indole-3-acetic acid (IAA) and α-naphthalene acetic acid (NAA) stimulated VrKu expression through the mitogen-activated protein kinase/extracellular signal-regulated kinase pathway. Altogether, it is thus proposed that 2,4-D and IAA (or NAA) regulate the expression of VrKu through two distinct pathways.

Intramolecular carboxylic group‐assisted cleavage of N‐(2‐hydroxyphenyl)phthalamic acid (7) and N‐(2‐methoxyphenyl)phthalamic acid (8): Absence of intramolecular general acid catalysis due to 2‐OH in 7

AbstractThe values of pseudo first‐order rate constants (kobs) for the cleavage of N‐(2‐hydroxyphenyl)phthalamic acid (7), obtained at 4.9 × 10−2 M HCl, 35°C, and within CH3CN content range 2–80% (v/v) in mixed aqueous solvent are smaller than kobs for the cleavage of N‐(2‐methoxyphenyl)phthalamic acid (8), obtained under almost similar experimental conditions, by nearly 1.5‐ to 2‐fold. These observations show the absence of expected intramolecular general acid catalysis due to 2‐OH group in 7. The values of kobs for the cleavage of 7 and 8 decrease by more than 20‐fold with the increase in the content of CH3CN from 2 to 80–82% (v/v) in mixed aqueous solvent. The kinetic data reveal that in acidic aqueous cleavage of 7, N‐cyclization (leading to the formation of imide) and O‐cyclization (leading to the formation of phthalic anhydride) vary from ∼10 to 15% and ∼90 to 85%, respectively, with the increase in CH3CN content from 2 to 80% (v/v). Similar increase in CH3CN content causes increase in N‐cyclization from ∼0 to 5% and decrease in O‐cyclization from ∼100 to 95% in the acidic aqueous cleavage of 8. Some speculative, yet conceivable, reasons for nearly 10 and 0% N‐cyclization in the cleavage of respective 7 and 8 at low content of CH3CN have been described. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 746–758, 2006

Silencing the flavonoid pathway in Medicago truncatula inhibits root nodule formation and prevents auxin transport regulation by rhizobia.

Legumes form symbioses with rhizobia, which initiate the development of a new plant organ, the nodule. Flavonoids have long been hypothesized to regulate nodule development through their action as auxin transport inhibitors, but genetic proof has been missing. To test this hypothesis, we used RNA interference to silence chalcone synthase (CHS), the enzyme that catalyzes the first committed step of the flavonoid pathway, in Medicago truncatula. Agrobacterium rhizogenes transformation was used to create hairy roots that showed strongly reduced CHS transcript levels and reduced levels of flavonoids in silenced roots. Flavonoid-deficient roots were unable to initiate nodules, even though normal root hair curling was observed. Nodule formation and flavonoid accumulation could be rescued by supplementation of plants with the precursor flavonoids naringenin and liquiritigenin. The flavonoid-deficient roots showed increased auxin transport compared with control roots. Inoculation with rhizobia reduced auxin transport in control roots after 24 h, similar to the action of the auxin transport inhibitor N-(1-naphthyl)phthalamic acid (NPA). Rhizobia were unable to reduce auxin transport in flavonoid-deficient roots, even though NPA inhibited auxin transport. Our results present genetic evidence that root flavonoids are necessary for nodule initiation in M. truncatula and suggest that they act as auxin transport regulators.

Atualizando a química orgânica experimental da licenciatura

The present contribution describes three different modern experiments for possible adoption in undergraduate organic chemistry laboratories. These are: 1. electrocatalytic hydrogenation of benzaldehyde to benzyl alcohol; 2. identification of three volatile components, obtained from pineapple fruit, by mass spectrometry and 3. microwave mediated fast synthesis of N-(p-chlorophenyl)phthalamic acid from phthalic anhydride and p-chloroaniline under solvent-free conditions. The experiments can be executed in a short period of time, putting the undergraduate student in contact with a variety of topics in organic chemistry and several techniques of analysis, showing multidisciplinarity in organic chemistry.

Polyhydroxyamic acid from 3,3′-dihydroxybenzidine and pyromellitic dianhydride as a fire-safe polymer

In order to assess the potential of the hydroxy-containing polyamic acid (PHAA) synthesized from 3,3′-dihydroxy benzidine and pyromellitic dianhydride for a fire-safe polymer, the cyclization pathway of PHAA has been investigated using a model compound prepared from 2-aminophenol and phthalic anhydride. The reaction was monitored by1H-nuclear magnetic resonance. N-(2-hydroxyphenyl)phthalamic acid is converted to N-(2-hydroxyphenyl)phthalimide at ca. 175°C, showing endothermic reaction. The imide structure is rearranged to the benzoxazole structure over ca. 400°C. These results are similar with that of PHAA. According to pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) data, water and carbon dioxide are released during the cyclization and rearrangement reaction. One DMAc molecule is complexed with one carboxyl acid group in PHAA, which accelerates the imidization process to release more easily the flame retardant, water.

Brassinosteroids interact with auxin to promote lateral root development in Arabidopsis.

Plant hormone brassinosteroids (BRs) and auxin exert some similar physiological effects likely through their functional interaction, but the mechanism for this interaction is unknown. In this study, we show that BRs are required for lateral root development in Arabidopsis and that BRs act synergistically with auxin to promte lateral root formation. BR perception is required for the transgenic expression of the beta-glucuronidase gene fused to a synthetic auxin-inducible promoter (DR5::GUS) in root tips, while exogenous BR promotes DR5::GUS expression in the root tips and the stele region proximal to the root tip. BR induction of both lateral root formation and DR5::GUS expression is suppressed by the auxin transport inhibitor N-(1-naphthyl) phthalamic acid. Importantly, BRs promote acropetal auxin transport (from the base to the tip) in the root. Our observations indicate that BRs regulate auxin transport, providing a novel mechanism for hormonal interactions in plants and supporting the hypothesis that BRs promote lateral root development by increasing acropetal auxin transport.