Mineralization of sulfonamides from wastewater using ozone-based systems

Ozone, UV/ozone, ozone/persulfate (PS) and UV/ozone/PS systems were used to mineralize sulfonamides. Sulfadiazine (SDZ), sulfamerazine (SMR) and sulfamethazine (SMZ) were the target compounds. The novel contribution of this study is its determination of the effects of PS addition, sulfonamide structure, pH and salinity on sulfonamide mineralization in ozone-based systems. The mineralization rate of sulfonamides satisfied pseudo-first-order kinetics. The SMZ mineralization rate constant in ozone, UV/ozone, ozone/PS and UV/ozone/PS systems at pH 5 were 0.0058; 0.0101; 0.0069 and 0.0802 min−1, respectively, and those at pH 7 were 0.0075; 0.0116; 0.0083 and 0.0873 min−1, respectively. The increase in the number of methyl-substituents in the heterocyclic group of SMZ and the corresponding increase in the steric hindrance of radical addition, reduced mineralization rates below those of SMR and SDZ. The addition of PS promoted sulfonamide mineralization in the ozone-based systems; conversely, salinity inhibited sulfonamide mineralization.

Heterocyclic group transfer reactions with I(iii) N-HVI reagents: access to N-alkyl(heteroaryl)onium salts via olefin aminolactonization

Complex N-alkyl (heteroaryl)onium salts are accessed via heterocyclic group transfer reactions of N-ligated I(iii) reagents with alkenoic acids. The reactions proceed in excellent yields, under mild conditions, and with broad substrate scope.

Heterocyclic Group Transfer Reactions with I(III) N-HVI Reagents: Access to N-Alkyl (Heteroaryl)onium Salts via Olefin Aminolactonization

<p>Pyridinium and related N-alkyl (heteroaryl)onium salts are versatile synthetic intermediates in organic chemistry, with applications ranging from ring functionalizations to provide diverse piperidine scaffolds to their recent emergence as radical precursors in deaminative cross couplings. Despite their ever-expanding applications, methods for their synthesis have seen little innovation, continuing to rely on a limited set of decades old transforms. Herein, we leverage (bis)cationic nitrogen-ligated I(III) hypervalent iodine reagents, or <i>N</i>-HVIs, as “heterocyclic group transfer reagents” to provide access to a broad scope of (heteroaryl)onium salts via the aminolactonization of alkenoic acids. The reactions proceed in excellent yields, under mild conditions, and are capable of incorporating a broad scope of sterically and electronically diverse aromatic heterocycles. The <i>N</i>-HVI reagents can be generated <i>in situ</i>, the products isolated via simple trituration, and subsequent derivatizations demonstrate the power of this platform for diversity-oriented synthesis of 6-membered nitrogen heterocycles. Mechanistic studies indicate the reaction proceeds via initial olefin activation followed by lactonization and subsequent intermolecular nucleophilic displacement of an (alkyl)(aryl)iodonium salt hypernucleofuge.</p>

Heterocyclic Group Transfer Reactions with I(III) N-HVI Reagents: Access to N-Alkyl (Heteroaryl)onium Salts via Olefin Aminolactonization

<p>Pyridinium and related N-alkyl (heteroaryl)onium salts are versatile synthetic intermediates in organic chemistry, with applications ranging from ring functionalizations to provide diverse piperidine scaffolds to their recent emergence as radical precursors in deaminative cross couplings. Despite their ever-expanding applications, methods for their synthesis have seen little innovation, continuing to rely on a limited set of decades old transforms. Herein, we leverage (bis)cationic nitrogen-ligated I(III) hypervalent iodine reagents, or <i>N</i>-HVIs, as “heterocyclic group transfer reagents” to provide access to a broad scope of (heteroaryl)onium salts via the aminolactonization of alkenoic acids. The reactions proceed in excellent yields, under mild conditions, and are capable of incorporating a broad scope of sterically and electronically diverse aromatic heterocycles. The <i>N</i>-HVI reagents can be generated <i>in situ</i>, the products isolated via simple trituration, and subsequent derivatizations demonstrate the power of this platform for diversity-oriented synthesis of 6-membered nitrogen heterocycles. Mechanistic studies indicate the reaction proceeds via initial olefin activation followed by lactonization and subsequent intermolecular nucleophilic displacement of an (alkyl)(aryl)iodonium salt hypernucleofuge.</p>

A Heterocyclic Polyurethane with Enhanced Self-Healing Efficiency and Outstanding Recovery of Mechanical Properties

A functional polyurethane based on the heterocyclic group was synthesized and its self-healing and mechanical properties were examined. To synthesize a heterocyclic polyurethane, a polyol and a heterocyclic compound with di-hydroxyl groups at both ends were blended and the blended solution was reacted with a crosslinker containing multiple isocyanate groups. The heterocyclic polyurethane demonstrates better self-healing efficiency than the conventional polyurethane with no heterocyclic groups. Furthermore, unlike the conventional self-healing materials, the heterocyclic polyurethane examined in this study shows an outstanding recovery of the mechanical properties after the self-healing process. These results are attributed to the unique supramolecular network resulting from the strong hydrogen bonding interaction between the urethane group and the heterocyclic group in the heterocyclic polyurethane matrix.

Exploring the syntheses, structures, topologies, luminescence sensing and magnetism of Zn(ii) and Mn(ii) coordination polymers based on a semirigid tricarboxylate ligand

Two Zn(ii)-CPs and two Mn(ii)-CPs were constructed from metal salts, H3cpota and N-heterocyclic group ligands. Their structures, magnetic properties and luminescence sensing properties have been studied in detail.

NMR analysis of a series of 1,2-bis(1-R-5-oxo-2,3-dihydro-1H-pyrrol-4-ylidene)ethanes and X-ray crystal structure analysis of theR= mesityl compound

Four tetramethyl 4,4′-(ethane-1,2-diylidene)bis[1-R-5-oxo-4,5-dihydro-1H-pyrrole-2,3-dicarboxylate] compounds, denoted class (1), are a series of conjugated buta-1,3-dienes substituted with a heterocyclic group. The compounds can be used as dyes and pigments due to their long-range conjugated systems. Four structures were studied using1H NMR,13C NMR and mass spectroscopy,viz.withR= 2,4,6-trimethylphenyl, (1a),R = cyclohexyl, (1b),R=tert-butyl, (1c), andR= isopropyl, (1d). A detailed discussion is presented regarding the characteristics of the three-dimensional structures based on NMR analysis and the X-ray crystal structure of (1a), namely tetramethyl 4,4′-(ethane-1,2-diylidene)bis[5-oxo-1-(2,4,6-trimethylphenyl)-4,5-dihydro-1H-pyrrole-2,3-dicarboxylate], C36H36N2O10. The conjugation plane and stability were also studiedviaquantum chemical calculations.