Synthesis and crystal structures of three Schiff bases derived from 3-formylacetylacetone and o-, m- and p-aminobenzoic acid

Treatment of 3-formylacetylacetone with the isomeric o-, m- and p-aminobenzoic acids led to the formation of the corresponding Schiff bases, namely, 3-[(2-carboxyphenylamino)methylidene]pentane-2,4-dione, 1, 3-[(3-carboxyphenylamino)methylidene]pentane-2,4-dione, 2, and 3-[(4-carboxyphenylamino)methylidene]pentane-2,4-dione, 3, all C13H13NO4, that contain a planar amino-methylene-pentane-2,4-dione core with a strong intramolecular N—H...O hydrogen bridge. The carboxyphenyl groups attached to the nitrogen atom are almost coplanar to the central molecular fragment. Depending on the position of the carboxyl unit, different supramolecular structures with hydrogen-bonding networks are formed in the three title structures.

Synthesis and Characterization of Heterocyclic Compounds Derived from Schiff base Glycerol Triester

Heterocyclic compounds were prepared from Schiff bases triester derivatives, the first step was included, p- aminobenzoic acids convert to p-amino benzoyl chloride in the presence of thionyl chloride then glycerol was added to form triesters compound A. second step reaction of triester product with the 4-nitrobenzaldehyde, and 3-amino benzaldehyde to produce M1, and M2. The third step. Involve reacted Schiff bases triester derivatives to give heterocyclic compounds M1S, M1A, M2P, and M2K. The structure of all compounds is monitored by (TLC), and identified by many techniques 1HNMR, FT-IR, and melting point.

FUNGICIDAL PROPERTIES OF N-(p-CARBOXYPHENYL)IMIDE-2,3-DICHLOROBICYCLO-[2.2.1]HEPT-5-EN-2,3-DICARBOXYLIC ACID

As a result of the interaction of substituted aminobenzoic acids and dichloromaleic anhydride in glacial acetic acid, various N-substituted imides of dichloromaleic acid have been obtained. Based on the diene synthesis of cyclopentadiene and N-substituted imides of dichloromaleic acid, N-(orthometa- and para-carboxyphenyl)imides of 2,3-dichlorocyclo-[2.2.1]hept-5-ene-2,3-dicarboxylic acid have been syn¬thesized. The obtained imides have been tested as a potential effective complex biologically active drug. The results of multiple tests have demonstrated that these compounds possess, simultangonsly, high fungicidal and bactericidal activity against cotton verticillus wilt. So, for a concentration of 0.1%, the obtained compounds almost completely destroy the fungus verticillum dahliae, as well as thionic iron-oxidizing and sulfate-reducing aerobic bacteria VKM V-458 and VKM V-1388

In vivo and in vitro reconstitution of unique key steps in cystobactamid antibiotic biosynthesis

Cystobactamids are myxobacteria-derived topoisomerase inhibitors with potent anti-Gram-negative activity. They are formed by a non-ribosomal peptide synthetase (NRPS) and consist of tailored para-aminobenzoic acids, connected by a unique α-methoxy-l-isoasparagine or a β-methoxy-l-asparagine linker moiety. We describe the heterologous expression of the cystobactamid biosynthetic gene cluster (BGC) in Myxococcus xanthus. Targeted gene deletions produce several unnatural cystobactamids. Using in vitro experiments, we reconstitute the key biosynthetic steps of linker formation and shuttling via CysB to the NRPS. The biosynthetic logic involves a previously uncharacterized bifunctional domain found in the stand-alone NRPS module CysH, albicidin biosynthesis and numerous BGCs of unknown natural products. This domain performs either an aminomutase (AM) or an amide dehydratase (DH) type of reaction, depending on the activity of CysJ which hydroxylates CysH-bound l-asparagine. Furthermore, CysQ O-methylates hydroxyl-l-(iso)asparagine only in the presence of the AMDH domain. Taken together, these findings provide direct evidence for unique steps in cystobactamid biosynthesis.

Pd(ii)-Catalyzed [4 + 1 + 1] cycloaddition of simple o-aminobenzoic acids, CO and amines: direct and versatile synthesis of diverse N-substituted quinazoline-2,4(1H,3H)-diones

Pd(ii)-Catalyzed modular synthesis of diverse quinazoline-2,4-(1H,3H)-diones through one-pot cascade cycloaddition of o-aminobenzoic acids with CO and amines can proceed efficiently under mild conditions in moderate to excellent yields.

Correction: Pd(ii)-Catalyzed [4 + 1 + 1] cycloaddition of simple o-aminobenzoic acids, CO and amines: direct and versatile synthesis of diverse N-substituted quinazoline-2,4(1H,3H)-diones

Correction for ‘Pd(ii)-Catalyzed [4 + 1 + 1] cycloaddition of simple o-aminobenzoic acids, CO and amines: direct and versatile synthesis of diverse N-substituted quinazoline-2,4(1H,3H)-diones’ by Xiaopeng Zhang et al., Green Chem., 2021, DOI: 10.1039/d0gc03254a.

Unsymmetrically Substituted Dibenzo[b,f][1,5]-diazocine-6,12(5H,11H)dione—A Convenient Scaffold for Bioactive Molecule Design

A novel approach for the synthesis of unsymmetrically substituted dibenzo[b,f][1,5]diazocine-6,12(5H,11H)diones has been developed. This facile three-step method uses variously substituted 1H-benzo[d][1,3]oxazine-2,4-diones (isatoic anhydrides) and 2-aminobenzoic acids as a starting materials. The obtained products were further transformed into N-alkyl-, N-acetyl- and dithio analogues. Developed procedures allowed the synthesis of unsymmetrical dibenzo[b,f][1,5]diazocine-6,12(5H,11H)diones and three novel heterocyclic scaffolds: benzo[b]naphtho[2,3-f][1,5]diazocine-6,14(5H,13H)dione, pyrido[3,2-c][1,5]benzodiazocine-5,11(6H,12H)-dione and pyrazino[3,2-c][1,5]benzodiazocine-6,12(5H,11H)dione. For 11 of the compounds crystal structures were obtained. The preliminary cytotoxic effect against two cancer (HeLa, U87) and two normal lines (HEK293, EUFA30) as well as antibacterial activity were determined. The obtained dibenzo[b,f][1,5]diazocine(5H,11H)6,12-dione framework could serve as a privileged structure for the drug design and development.

Synthesis, Spectroscopic Characterization and Photoactivity of Zr(IV) Phthalocyanines Functionalized with Aminobenzoic Acids and Their GO-Based Composites

Two complexes of bis(aminobenzoato)zirconium(IV) phthalocyanine and their graphite oxide-based composites were synthesized and characterized in respect of their photochemical properties. Structures of phthalocyanines were confirmed by Mass and infrared spectroscopies. The absorption and photoluminescence spectra were investigated to show various behavior of the complexes in different media (dimethyl sulfoxide and saline). Optical technique (monitoring variation of absorption spectra of diphenylisobenzofuran used as an indicator) was used to prove the generation of reactive oxygen species (ROS) by under light irradiation in the range of the first biological window. The photoactivity of the materials was compared and discussed in terms of their potential ability to be used in biomedical applications, for example, as photosensitizers in photodynamic therapy.