Tetrabromophthalic Anhydride Research Articles

Suspect and non-target screening of chemicals of emerging Arctic concern in biota, air and human serum

Contaminants of emerging concern receive increasing attention in the Arctic environment. The aim of this study was to screen for chemicals of emerging Arctic concern (CEACs) in different types of Arctic samples including biota, air and human serum. We used a combination of gas chromatography (GC) and liquid chromatography (LC) with high resolution mass spectrometry (HRMS) for suspect and non-target screening (NTS). Suspect screening of 25 CEACs was based on published in-silico approaches for the identification of CEACs and revealed tetrabromophthalic anhydride (TBPA) in pilot whale and air, albeit with low detection frequencies (17 and 33%, respectively). An NTS workflow detected 49, 42, 31 and 30 compounds in pilot whale, ringed seal, air, and human serum, respectively, at confidence level 2 and 3. Although legacy POPs still dominated the samples, 64 CEACs were tentatively identified and further assessed for persistence (P), bioaccumulation (B), mobility (M), toxicity (T), and long-range transport potential (LRTP). While four PBT compounds were identified, 37 PMT substances dominated among these 64 compounds. Our study indicated that many chemicals of potential risk might be present in Arctic samples and would benefit from confirmation and further studies of their transport to and accumulation in the Arctic environment.

Synthesis, Modification and Characterization of New Phenolic Resins linked to Tetrabromophthalimide

The present work aimed to synthesize new phenol resins via incorporation of structural modification through introducing new phenolic compounds containing cyclic imide moiety in reaction with formaldehyde. The synthesis of these new resins involved three steps. First, one of the three N-(hydroxyphenyl)tetrabromophtalamic acids 1-3 were processed via a reaction between tetrabromophthalic anhydride and aminophenols. Amic acids 1-3 were dehydrated in the second step by smelting, producing the identical N-(hydroxyphenyl)tetrabromophthalimides 4-6. The new imides represent the new phenolic component that was presented in condensation reaction with formaldehyde in the third step, creating the target phenolic resins 7-9. The work also involved curing the new resins through esterification of phenolic OH groups by treatment with benzoyl chloride. The chemical structures of prepared compounds were confirmed according to FT-IR, 1H NMR, and 13C NMR spectral data. As a conclusion, the present work supply of new phenolic resins and the presence of the cyclic imide (tetrabromophthalimide) moiety in their structures exhibit high softening points and resistance to solubility, which fit with some applications, while subsequent curing through esterification exhibits better solubility and lower softening points, which fit with other applications.

Copper(II) pseudoatrane appended heterobimetallic 2D‐MOF: A multi‐functional material with catalytic and sensing properties

A maiden two‐dimensional atrane‐based heterobimetallic MOF (2) was constructed employing a novel tripodal ligand N{CH2COOH}2{CH2(2‐t‐Bu‐4‐CH3‐C6H2‐OH)} (1). Single‐crystal X‐ray diffraction depicted the formation of [4.3.3.01,5] pseudoatrane cage in which copper(II) ions attained trigonal bipyramidal geometry. Besides, the co‐existing sodium(I) ions acquired a pentagonal bipyramidal geometry produced by methanol molecules and free carboxylate sites of the ligand. This compound is the first of its kind where the sequential binding of copper(II) pseudoatrane cage and hepta‐coordinated sodium ion generated a heterobimetallic metal–organic framework with a sheet‐like structure. The TEM and SEM images of the MOF having stability up to 250°C revealed the formation of spherical structures (~78 nm) with flower‐like morphology. The heterobimetallic 2D‐MOF was proved to be a multifunctional material as it successfully catalysed Friedel–Craft's alkylation of Indole with beta‐nitrostyrene as well as utilised for the efficient detection of toxic brominated flame retardants through spectrophotometric and colorimetric studies. Remarkably, the best catalysis results were seen using DCM as a solvent, and the alkylation product obtained from the reaction of 2‐methylindole with 2‐Br‐β‐nitrostyrene showed an extraordinary yield of 98%. Besides, the 2D‐MOF showed a selective response with pentabromophenol, and tetrabromophthalic anhydride with quenching in peak on the addition of TBPA while shifting of the peak was observed from 457 to 402 nm with PBP. The practical application of the MOF was explored by its successful incorporation into portable silica strips for on‐the‐spot detection of BFRs.

Synthesis and Antimicrobial Study of New Fused Thiazolo[3,2-b]triazine, Triazolo[4,3-b]triazine, and 1,2,4-Triazinone Derivatives

6-[2-(Furan-2-yl)ethyl]-3-sulfanylidene-3,4-dihydro-1,2,4-triazin-5(2H)-one (1) reacted with chloroacetone to give S-acetonyl derivative which cyclized in ethanol under reflux to afford 6-[2-(furan-2-yl)-ethyl]-3-methyl-7H-[1,3]thiazolo[3,2-b][1,2,4]triazin-7-one. 2,4-Bis(furan-2-carbonyl)-6-[2-(furan-2-yl)-ethyl]-3-sulfanylidene-3,4-dihydro-1,2,4-triazin-5(2H)-one and 3-amino-6-[2-(furan-2-yl)ethyl]-2-{[6-(2-(furan-2-yl)ethyl)-5-oxo-2,5-dihydro-1,2,4-triazin-3-yl]sulfanyl}-3-methyl-7H-[1,3]thiazolo[3,2-b][1,2,4]-triazin-7-one were prepared by reaction of 1 with furoyl chloride and dibromoacetonitrile, respectively. Compound 1 also reacted with formaldehyde and with formaldehyde and benzylamine to give 2-hydroxymethyl and 2-(benzylaminomethyl) derivatives. The alkylation of 1 with methyl iodide, followed by treatment with hydrazine hydrate, afforded 6-[2-(furan-2-yl)ethyl]-2-hydrazinyl-1,2,4-triazin-5(2H)-one. Reactions of the latter with aromatic aldehydes and formic acid furnished 3-aryl- and 3-unsubstituted 6-[2-(furan-2-yl)ethyl][1,2,4]tri-azolo[4,3-b][1,2,4]triazin-7(1H)-ones, respectively, and triacetyl and tetrabromophthalazinyl derivatives were obtained by reacting hydrazinyltriazinone with acetic anhydride and tetrabromophthalic anhydride. The newly synthesized compounds were evaluated for their antimicrobial activity against some bacterial and fungal strains.

Investigation of the reactivity of 4-amino-5-hydrazineyl-4H-1,2, 4-triazole-3-thiol towards some selected carbonyl compounds: synthesis of novel triazolotriazine-, triazolotetrazine-, and triazolopthalazine derivatives

Abstract The reactivity of 4-amino-5-hydrazineyl-4H-1,2,4-triazole-3-thiol (1) towards several carbonyl compounds was investigated. We have found that on treatment of 1 with isatoic anhydride (2), 1,8-naphthalic anhydride (4), diphenic anhydride (6), pyromellitic dianhydride (8), and tetrabromophthalic anhydride (10), the reaction proceeds to give triazolotetrazine- and triazolophthalazine derivatives in good yields using simple experimental procedures. The structure of the synthesized compounds was confirmed using different spectroscopic data (1H NMR, 13C NMR, mass spectrometry, and elemental analysis). The mechanism of the obtained products was also discussed.

Investigation of DNA binding and molecular docking propensity of phthalimide derivatives: in vitro antibacterial and antioxidant assay

A series of N-substituted tetrabromphthalimide derivatives was synthesized by condensation reaction using tetrabromophthalic anhydride with 3,5-diamino-1,2,4-triazole/ 2,6-diaminopyridine/ 2,6-diamino-4-hydroxy pyrimidine/ o-tolidine. All the synthesized phthalimide derivatives were characterized by elemental analysis, infrared, and NMR spectroscopy. In vitro antibacterial evaluation was carried out for the synthesized compounds. Results revealed that compound 1 showed potential activity against Escherichia coli (100 μg/mL) and Streptococcus mutans (150 μg/mL). On the basis of antibacterial activity, compound 1 was selected for DNA binding interaction, though DNA target most of the antibacterial drugs. The DNA binding modes of the compound 1 with Ct-DNA (calf thymus) were studied by absorption measurements, hydrodynamic measurements and cyclic voltammetry methods. Molecular docking also confirms that compound 1 recognizes both the strands of the DNA dodecamer d(CGCGAATTCGCG)2 within minor groove and showing the best binding capability with the duplex. Compound 1 also showed better antioxidant activity by 2,2-diphenyl-1-picryl-hydrazyl (DPPH) free radical and hydrogen peroxide.

Synthesis, Characterization and DFT Study of 4,4′-Oxydianiline Imines as Precursors of Tetrahalo-1,3-oxazepine-1,5-dione

This work presents four Schiff bases derived from 4,4′-Oxydianiline, distinguished by the para substituted halogen of benzaldehyde. These bases were used to synthesize eight compounds of di-1,3-oxazepine by direct condensation with tetrachloro phthalic anhydride and tetrabromo phthalic anhydride. The reactions were monitored with TLC and all structures were characterized using spectroscopic techniques such as FT-IR, 1H-NMR, 13C-NMR and C, H, N techniques. On the other hand, a theoretical study by Density Functional Theory (DFT) for the electronic structures was intended to study the effects of para-substituted halogen of benzaldehyde on the electronic structure of synthesized Schiff bases by using the Gaussian program. Theoretical results indicate that there is no effect of halogen atoms except for bromine on HOMO and LUMO energies of the synthesized compounds.

Quantitative Metabolite Profiling of an Amino Group Containing Pharmaceutical in Human Plasma via Precolumn Derivatization and High-Performance Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry.

Quantitative determination of the candidate drug molecule and its metabolites in biofluids and tissues is an inevitable step in the development of new pharmaceuticals. Because of the time-consuming and expensive nature of the current standard technique for quantitative metabolite profiling, i.e., radiolabeling followed by high-performance liquid chromatography (HPLC) with radiodetection, the development of alternative methodologies is of great interest. In this work, a simple, fast, sensitive, and accurate method for the quantitative metabolite profiling of an amino group containing drug (levothyroxine) and its metabolites in human plasma, based on precolumn derivatization followed by HPLC-inductively coupled plasma mass spectrometry (ICPMS), was developed and validated. To introduce a suitable "heteroelement" (defined here as an element that is detectable with ICPMS), an inexpensive and commercially available reagent, tetrabromophthalic anhydride (TBPA) was used for the derivatization of free NH2-groups. The presence of a known number of I atoms in both the drug molecule and its metabolites enabled a cross-validation of the newly developed derivatization procedure and quantification based on monitoring of the introduced Br. The formation of the derivatives was quantitative, providing a 4:1 stoichiometric Br/NH2 ratio. The derivatives were separated via reversed-phase HPLC with gradient elution. Bromine was determined via ICPMS at a mass-to-charge ratio of 79 using H2 as a reaction gas to ensure interference-free detection, and iodine was determined at a mass-to-charge ratio of 127 for cross-validation purposes. The method developed shows a fit-for-purpose accuracy (recovery between 85% and 115%) and precision (repeatability <15% RSD). The limit of quantification (LoQ) for Br was approximately 100 μg/L.

Evaluation of Common Use Brominated Flame Retardant (BFR) Toxicity Using a Zebrafish Embryo Model.

Brominated flame retardants (BFRs) are used to reduce the flammability of plastics, textiles, and electronics. BFRs vary in their chemical properties and structures, and it is expected that these differences alter their biological interactions and toxicity. Zebrafish were used as the model organism for assessing the toxicity of nine structurally-diverse BFRs. In addition to monitoring for overt toxicity, the rate of spontaneous movement, and acetylcholinesterase and glutathione-S-transferase (GST) activities were assessed following exposure. The toxicities of BFRs tested can be ranked by LC50 as tetrabromobisphenol A (TBBPA) < 4,4′-isopropylidenebis[2-(2,6-dibromophenoxyl)ethanol] (TBBPA-OHEE) < Pentabromochlorocyclohexane (PBCH) < 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (TBB) < hexabromocyclododecane (HBCD) < hexabromobenzene (HBB) < Tetrabromophthalic anhydride (PHT4). No adverse effect was observed in di(2-ethylhexyl) tetrabromophthalate (TBPH) or dibromoneopentyl glycol (DBNPG)-treated embryos. The rate of spontaneous movement was decreased in a concentration-dependent manner following exposure to four of the nine compounds. GST activity was elevated following treatment with PBCH, TBBPA, HBCD, and HBB. The results indicate that exposure to several BFRs may activate an antioxidant response and alter behavior during early development. Some of the BFRs, such as TBBPA and TBBPA-OHEE, induced adverse effects at concentrations lower than chemicals that are currently banned. These results suggest that zebrafish are sensitive to exposure to BFRs and can be used as a comparative screening model, as well as to determine alterations in behavior following exposure and probe mechanisms of action.

Synthesis of Bisphthalamic Acids for the Preparation of Glass‐Reinforced Composites of Multifunctional Epoxy Resin of Bisphenol‐C and Their Physicochemical Properties

ABSTRACTBisphthalamic acids of tetrahydrophthalic anhydride (THPA), tetrachlorophthalic anhydride (TCPA), tetrabromophthalic anhydride (TBPA), and 4,4′‐diamino diphenylsulfone (DDS), 4,4′‐diaminodiphenylether (DDE), and 4,4′‐diaminodiphenyl methane (DDM) were synthesized and used as hardeners for multifunctional epoxy resin of bisphenol‐C(EBCF). Glass‐reinforced composites (G‐EBCF‐THPA, G‐EBCF‐TCPA, G‐EBCF‐TBPA, G‐EBCF‐THPADDS, G‐EBCF‐TCPADDS, G‐EBCF‐TCPADDE, and G‐EBCF‐TCPADDM) were fabricated by hand layup followed by compression molding technique at 140/170°C under 2 bar pressure for 6/15 h. Glass composites possess good tensile strength (99–168 MPa), flexural strength (131—270 MPa), flexural modulus (5419–7987 MPa), impact strength (19–36 kg m−2), Barcol hardness (31–44), electric strength (7.2–8.9 kV mm−1), volume resistivity (1 × 1012 to 1.9 × 1012 ohm cm), and 13–15.8% water absorption indicated their usefulness for low load bearing housing, electrical, and marine applications.

Synthesis and Characterisation of New Modified Anti-microbial Polyesteramide Resins by Partial Replacement with the Ingredient Source of The Polybasic Acid Based on Tetrabromophthalic Anhydride for Organic Surface Coatings

Synthesis and Characterisation of New Modified Anti-microbial Polyesteramide Resins by Partial Replacement with the Ingredient Source of The Polybasic Acid Based on Tetrabromophthalic Anhydride for Organic Surface Coatings

Synthesis and properties of novel brominated chiral polyamides derived from 5-[4-(2-tetrabromophthalimidylpropanoylamino)benzoylamino]isophthalic acid and aromatic diamines

A novel aromatic chiral dicarboxylic acid, 5-[4-(2-tetrabromophthalimidylpropanoylamino)benzoylamino]isophthalic acid was synthesized in three steps in high yield and purity starting from tetrabromophthalic anhydride and l-alanine. A series of new soluble, thermally stable and optically active polyamides (PA)s having pendent tetrabromophthalimide, flexible asymmetrical and benzamide groups with flame retardancy properties have been successfully prepared using triphenyl phosphite/pyridine in the presence of calcium chloride and N-methyl-2-pyrrolidone (NMP). The resulting new polymers were obtained in good yields, inherent viscosities ranging between 0.36 and 0.63 dL g−1 and were characterized with FT-IR, 1H NMR, specific rotation and thermogravimetric analysis techniques. Bulky pendent groups of the polymer chains disturb interchain and intrachain interactions and make these polymers readily soluble in various solvents, such as NMP, N,N-dimethylacetamide, dimethyl sulfoxide, and N,N-dimethylformamide. The resulting PAs were thermally stable, with 10 % weight loss recorded at 432 and 478 °C in the nitrogen atmosphere. In addition, due to existence of chiral center and optical activity of these polymers, they have potential to be utilized as chiral stationary phase in chromatography technique for the separation of racemic mixtures.

Molecular motion, dielectric response, and phase transition of charge-transfer crystals: acquired dynamic and dielectric properties of polar molecules in crystals.

Molecules in crystals often suffer from severe limitations on their dynamic processes, especially on those involving large structural changes. Crystalline compounds, therefore, usually fail to realize their potential as dielectric materials even when they have large dipole moments. To enable polar molecules to undergo dynamic processes and to provide their crystals with dielectric properties, weakly bound charge-transfer (CT) complex crystals have been exploited as a molecular architecture where the constituent polar molecules have some freedom of dynamic processes, which contribute to the dielectric properties of the crystals. Several CT crystals of polar tetrabromophthalic anhydride (TBPA) molecules were prepared using TBPA as an electron acceptor and aromatic hydrocarbons, such as coronene and perylene, as electron donors. The crystal structures and dielectric properties of the CT crystals as well as the single-component crystal of TBPA were investigated at various temperatures. Molecular reorientation of TBPA molecules did not occur in the single-component crystal, and the crystal did not show a dielectric response due to orientational polarization. We have found that the CT crystal formation provides a simple and versatile method to develop molecular dielectrics, revealing that the molecular dynamics of the TBPA molecules and the dielectric property of their crystals were greatly changed in CT crystals. The TBPA molecules underwent rapid in-plane reorientations in their CT crystals, which exhibited marked dielectric responses arising from the molecular motion. An order-disorder phase transition was observed for one of the CT crystals, which resulted in an abrupt change in the dielectric constant at the transition temperature.

Novel nanocomposites obtained by dispersion of LDH modified with N‐tetrabromophthaloyl‐glutamic in poly(amide‐imide) having N‐trimellitylimido‐l‐leucine and 4,4′‐diaminodiphenylether units

Layered double hydroxides (LDHs) have attracted much attention as nanofillers in polymer nanocomposites (NCs) due to their particular surface structural, positively charged layer and so on. In this study, a chiral diacid was synthesized by the reaction of tetrabromophthalic anhydride and glutamic acid. LDH was modified by co‐precipitation of aluminum nitrate, magnesium nitrate, and glutamic acid containing diacid. Chiral poly(amide‐imide) (PAI) was synthesized by direct polycondensation reaction of N‐trimellitylimido‐l‐leucine and 4,4′‐diaminodiphenylether. Different NCs of the obtained modified LDHs and the chiral PAI were prepared in a short time using ultrasonic technique. The morphology and the structure of the obtained samples were characterized by Fourier transform infrared, thermogravimetric analysis (TGA), field emission scanning electron microscopy, transmission electron microscopy, and X‐ray diffraction analysis. TGA of the NCs showed a special order in thermal stability in compression with the neat PAI owing to the uniform distribution of the nanofillers. POLYM. COMPOS., 37:1323–1329, 2016. © 2014 Society of Plastics Engineers

Synthesis and performance of new modified reactive flame-retardant alkyd resin based on tetrabromophthalic anhydride as varnish for surface coatings

There exist two distinct approaches to achieving flame retardancy in polymers, namely the additive type and the reactive type. In this case, new modified reactive flame-retardant (FR) alkyd resins (short, medium, and long oil alkyd) were produced by means of a condensation polymerization reaction between a linseed oil fatty acid and glycerol, to produce the monoglyceride as the ingredient source of the polyol used. This then reacted with phthalic anhydride, which was partially replaced with tetrabromophthalic anhydride (TBPA), as the ingredient source of the dibasic acid. The resulting resin was characterized using FTIR and 1H NMR spectral studies. The coatings of 50 ± 5 µm thickness were applied to the surface of wood, glass panels, and mild steel strips by means of a brush. The fire retardant capacity of the modified reactive FR alkyd resins was assessed using the limiting oxygen index (LOI) test. The physical, mechanical, and chemical properties were also examined to evaluate any drawbacks associated with the modification. The results of the LOI test indicate that the modified reactive FR alkyd resins exhibit an improved flame retardancy effect following an increase in the TBPA content within the alkyd resin backbone structure. Improvement to the mechanical properties of the modified resins was also observed, but chemical resistance was not significantly changed. Finally, the prepared reactive FR alkyd resins were observed to overcome a range of problems that weaken the attraction of additive FRs namely, poor compatibility, leaching, and the reduction in mechanical properties.

Surface treatment of nano ZnO using 3,4,5,6-tetrabromo-N-(4-hydroxy-phenyl)-phthalamic acid as novel coupling agent for the preparation of poly(amide–imide)/ZnO nanocomposites

Technological developments during the last century have led to the use of materials that inhibit or resist the spread of fire, because modern world with the increase in electronic products presents a greater risk of fire dangers. In line with this goal, a novel modifier containing bromine elements with flame retardancy potential for the surface modification of ZnO nanoparticles was produced from the reaction between tetrabromophthalic anhydride and p-aminophenol. For the synthesis of nanocomposites (NCs), the modified ZnO was embedded in the poly(amide–imide) (PAI) matrix under ultrasonic conditions. Samples were characterized by Fourier transform infrared, thermogravimetric analysis (TGA), X-ray diffraction, transmission electron microscopy, field emission scanning electron microscopy and UV-visible (UV/Vis) techniques. TGA results indicated that the addition of modified ZnO into the PAI matrix increases in the thermal decomposition temperatures of the obtained NCs and that the UV/Vis absorbance of NCs was examined and displayed better UV-protection property than the pure PAI.

The Simultaneous Determination of Six Flame Retardants in Water Samples Using SPE Pre-concentration and UHPLC-UV Method

Analytical method for the determination of six flame retardants (FRs) from two groups was proposed. These groups included the brominated flame retardants (BFRs) 3,3′,5,5′-tetrabromobisphenol A (TBBPA), 1,2,5,6,9,10-hexabromocyclododecane (HBCD) and tetrabromophthalic anhydride (TBPA) and triester organophosphate flame retardants (OPFRs) tris(2,3-dibromopropyl) phosphate (TBPP), ethylhexyl diphenyl phosphate (EHDP) and triphenyl phosphate (TPhP). Reversed phase ultrahigh-performance liquid chromatography (UHPLC) with a UV detector, different chromatographic columns, different mobile phases and gradient elution programmes were used to obtain the best separations within the shortest possible time. Solid-phase extraction (SPE) was examined as a pre-concentration step from distilled water. The column with the highest recoveries (the Bond Elut ENV column gave recoveries over 70 % for all compounds) was then tested on 1-L blank surface water samples. The proposed analytical procedure was applied for the determination of FRs in surface water samples. The concentrations of FRs found in water samples ranged from 0.03 (TPhP) to 3.10 μg L−1 (HBCD). Method detection limits (MDLs) ranged from 0.008 to 0.518 μg L−1, and method quantification limits (MQLs) ranged from 0.023 to 1.555 μg L−1 for all compounds.

Thermal Study of Anhydrides Cured Tetrafunctional Cardo Epoxy Resin

Tetrafunctional cardo epoxy resin (EBCF) was cured by using 10 wt% maleic anhydride (MA), pyromellitic dianhydride (PMDA), phthalic anhydride (PA), tetrahydrophthalic anhydride (THPA), tetrabromophthalic anhydride (TBPA), and tetrachlorophthalic anhydride (TCPA) as hardeners at 120°C for 40–105 min (gel time) and then postcured 1 h at 130°C. Gel time is found to depend on the structure of the anhydrides used. Cured samples were found insoluble in common solvents. Cured and uncured EBCF were characterized by FTIR, DSC, and TGA techniques. Cured and uncured resins followed multistep degradation reactions. Kinetic parameters, namely, order of degradation, energy of activation, frequency factor, and entropy change, were determined according to the Anderson-Freeman method and interpreted in light of the nature of hardeners used for curing purpose. The resins followed integral or fractional order degradation kinetics. Complex degradation reactions are due to different types of linkages in cured resins. Both nature and structure of resin and hardeners affected the curing behavior and the resultant thermal properties of the cured resins.

Facile Synthesis of Thiazole, Thiazine and Isoindole Derivatives via EDA Approach and Conventional Methods

The reactivity of N-amidinothiourea (1) as an electron donor towards several electron-accepting functional groups via electron-donor-acceptor (EDA) interaction has been studied. Thus on treatment of 1 with either 1,1,2,2-tetracyanoethylene (TCNE, 2), 2,3-dicyano-1,4-naphthoquinone (DCNQ, 4), 2,3,5,6-tetrabromo-1,4-benzoquinone (BHL-p, 6), 2,3-dichloro-1,4-naphthoquinone (DCHNQ, 8), 2,3,5,6-tetrachloro-1,4-benzoquinone (CHL-p, 13), 2,3-dicyano-5,6-dichloro-1,4- benzoquinone (DDQ, 15), 2-dicyanomethyleneindan-1,3-dione (CNIND, 17), 2-(2-oxoindolin-3- ylidene)malononitrile (19), and/or dimethyl acetylenedicarboxylate (DMAD, 21), the reaction proceeds to give thiazole and thiazine derivatives, respectively. However, isoindole derivatives 24 and 26 were formed on heating of 1 with either tetrabromophthalic anhydride and=or o-phthalaldehyde, respectively. The products were fully characterized according to their spectral data. The mechanisms of formation of the products have been rationalized.

Condensation Reactions of 2-Aminobenzohydrazide with Various Carbonyl Compounds

Technical iodine was found to catalyze the condensation between 2-aminobenzohydrazide (1) and some aldehydes and ketones in absolute ethanol under mild conditions to afford hydrazone and quinazoline derivatives, respectively. Condensation of 1with terephthalaldehyde (2) in 1 : 1 molar ratios afforded the hydrazone 3, while hydrazone 4was formed on using a double molar ratio of 1. On the other hand, compound 1condensed with 4-formyl [2.2]paracyclophane (5) to give the hydrazone 6. However, spiro-quinazolines 8, 10, 12, and 14 were formed when compound 1reacted with ketones such as N-benzylpiperidone (7), indane-1,2,3-trione (9), cyclohexane-1,2-dione (11), and dimedone (13), respectively. Treatment of 1with tetrabromophthalic anhydride (TBPA, 18) and pyromellitic dianhydride (PMDA, 20) furnished phthalazino-quinazoline 19 and 21, respectively. The products were fully characterized according to their spectral analyses. The mechanisms of formation of the products have been rationalized.