EVIDENCE OF FORMATION AND DECAY, AND EFFECT OF THE ZWITTERIONIC INTERMEDIATE ON THE REACTION MECHANISM OF THE REACTION BETWEEN TRIPHENYLPHOSPHINE AND DIMETHYL ACETYLENDICARBOXYLATE HAS BEEN INVESTIGATED IN AQUEOUS-ORGANIC SOLVENTS BY APPLYING A STOPPED-FLOW TECHNIQUE [1, 2].SPECTRAL ANALYSES ON THE TWO-COMPONENT REACTION WAS CONFIRMED THE EXISTENCE OF THE ZWITTERIONIC INTERMEDIATE. STEP1 OF THE REACTION INVOLVING THE FORMATION AND DECAY OF THE ZWITTERIONIC INTERMEDIATE (ZI) WAS RECOGNIZED AS A FAST STEP. ALSO, PRO-K ANALYZER WAS CONFIRMED THE EXISTENCE OF 3 SPECIES ASSIGNED AS TPP, DMAD AND ZI AND AN EQUILIBRIUM REACTION MODEL (A+B<>C) FOR THE STEP1 OF THE TWO-COMPONENT REACTION. EXPERIMENTAL KINETIC DATA (K1, K-1) ALONG WITH ACTIVATION PARAMETERS (DG ¹, DS¹ AND DH¹) OF THE REACTION WERE RECOGNIZED [3].

ELECTROCHEMISTRY HAS EMERGED AS A POWERFUL TOOL FOR THE SYNTHESIS OF COMPLEX ORGANIC MOLECULES. UNIQUE SELECTIVITY BECAUSE OF IN SITU FORMATION OF AN ACTIVE SPECIES AT THE INTERFACE, INVERSION IN POLARITY BY TRANSFER OF ELECTRON AND VARIABILITY IN PRODUCT FORMATION BY CONTROL OF POTENTIAL ARE SOME OF ADVANTAGE OF ELECTROSYNTHESIS. ON THE OTHER HAND, THE ELECTROCHEMICAL OXIDATION OF AROMATIC AMINES IS QUITE COMPLEX, LEADING TO A VARIETY OF PRODUCTS DEPENDING ON THEIR STRUCTURE AND ELECTROLYSIS CONDITIONS. IN THIS DIRECTION, THE DEVELOPMENT OF A SIMPLE SYNTHETIC ROUTE FOR THE SYNTHESIS OF A UNIQUE ORGANIC COMPOUND FROM READILY AVAILABLE REAGENTS IS THE MAJOR TASKS IN THIS PAPER. IN THE PRESENT PAPER, THE ELECTROCHEMICAL DIMERIZATIONS OF N, N -DIALKYL- P -PHENYLENEDIAMINES VIA ANODIC OXIDATION OF N, N -DIETHYL- P -PHENYLENEDIAMINE AND N, N -DIMETHYL- P -PHENYLENEDIAMINE ARE DESCRIBED. THE MECHANISM OF DIMERIZATION HAS BEEN STUDIED IN AQUEOUS SOLUTION USING CYCLIC VOLTAMMETRY AND CONSTANT-CURRENT COULOMETRY. THE PRODUCTS ARE IDENTIFIED BY NMR, IR AND MS.THE WORK HAS LED TO THE DEVELOPMENT OF A FACILE ELECTROCHEMICAL METHOD FOR THE SYNTHESIS OF NEW DIMMER.

MULTICOMPONENT REACTIONS (MCRS) ARE AN IMPORTANT CLASS OF CONVERGENT ORGANIC REACTIONS, INWHICH THREE OR MORE STARTING MATERIALS REACT TO FORM A PRODUCT THAT CONTAINS ATOMS DERIVED FROM ALL PARTICIPATING REAGENTS, OFTEN DENOTED AS HIGH ATOM ECONOMY. THE ABILITY OFISOCYANIDES TO UNDERGO FACILE ADDITIONS WITH BOTH NUCLEOPHILES AND ELECTROPHILES MAKES IT APOPULAR REACTANT CLASS FOR THE DEVELOPMENT OF NOVEL MCRS….

BACKGROUND: IMIDAZOLONES ARE PRESENT IN MANY NATURAL PRODUCTS WHICH POSSESS WIDE SPECTRUM OF BIOACTIVITIES. IMIDAZOLONE-BASED HETEROCYCLES PLAY AN IMPORTANT ROLE IN VARIOUS BIOCHEMICAL PROCESSES [1]. SEVERAL METHODS HAVE BEEN DEVELOPED FOR CONSTRUCTION OF THE IMIDAZOLONE RING SYSTEM [2]. MOST OF THESE METHODS INVOLVED THE USE OF HAZARDOUS CHEMICALS SUCH AS PHOSGENE, TOXIC CHLORINATED SOLVENTS OR HARSH REACTION CONDITIONS. THUS, THE DEVELOPMENT OF NEW SYNTHETIC PROTOCOLS UNDER MILD REACTION CONDITIONS IS OF INTEREST.METHODS: KETENIMINES CAN PARTICIPATE IN CONSTRUCTION OF SKELETONS OF VARIOUS HETEROCYCLES WERE SUCCESSFULLY SYNTHESIZED [3]. AMONG METHODS FOR THE GENERATION OF KETENIMINES, THE CU-CATALYZED AZIDE-ALKYNE CYCLOADDITION ATTRACTED MUCH ATTENTION. APPLYING THIS STRATEGY, WE PRESENT A NOVEL CU(I)-CATALYZED SYNTHESIS OF FUNCTIONALIZED 5- SULFONYLIMINO-2-IMIDAZOLONES FROM DIALKYL AZODICARBOXYLATES AND SULFONOKETENIMIDES, GENERATED FROM TERMINAL ALKYNES AND SULFONYL AZIDES.RESULTS: INITIALLY, PHENYLACETYLENE, P-TOLUENESULFONYL AZIDE, AND DIISOPROPYL AZODICARBOXYLATE WERE SELECTED AS THE MODEL SUBSTRATES. CATALYSTS SUCH AS CUI, CUBR, CUCL, CU2O, AND CU POWDER WERE TESTED WITH CUI GIVING THE BEST RESULTS.CONCLUSION: WE PRESENT A NOVEL CU(I)-CATALYZED SYNTHESIS OF FUNCTIONALIZED 5-SULFONYLIMINO-2-IMIDAZOLONES FROM DIALKYL AZODICARBOXYLATES AND SULFONOKETENIMIDES, GENERATED FROM TERMINAL ALKYNES AND SULFONYL AZIDES.

P-PHENYLENEDIAMINE AND RELATED COMPOUNDS ARE OF PARTICULAR INTEREST DUE TO THEIR WIDE RANGE OF CHEMICAL APPLICATIONS AND BIOLOGICAL ISSUES. DESPITE THE WIDE APPLICATIONS OF THESE COMPOUNDS IN PROCESSES SUCH AS RUBBER PRODUCTS (AS ANTIOXIDANTS), HAIR DYE FORMULATIONS (AS PRECURSOR) AND IN THE MANUFACTURE OF AZO DYES (AS INTERMEDIATE), HOWEVER, THEY INDUCE OXIDATIVE STRESS AND ARE EXTREME SENSITIZER THAT MAY LEAD TO CONTACT ALLERGY AND DERMATITIS AS WELL AS SEVERE FACIAL SWELLINGS [1].IN THIS WORK, THE ELECTROCHEMICAL OXIDATION OFN, N -DIALKYL- P -PHENYLENEDIAMINES HAVE BEEN STUDIED IN THE PRESENCE OF SULFITE ION AS A NUCLEOPHILE IN AQUEOUS SOLUTION USING CYCLIC VOLTAMMETRY AND CONTROLLED-POTENTIAL COULOMETRY. A PLAUSIBLE MECHANISM FOR THE OXIDATION OF N, N-DIALKYL- P -PHENYLENEDIAMINE AND THEIR REACTIONS WITH SULFITE IS PRESENTED. THE RESULTS INDICATE THAT THE QUINONE-DIIMINE OBTAINED FROM ELECTOOXIDATION OFN, N -DIETHYL-P-PHENYLENEDIAMINE [2, 3] PARTICIPATS IN A MICHAEL TYPE REACTION WITH SULFITE ION TO FORM THE CORRESPONDING SULPHONATED DERIVATIVES. THE ELECTROCHEMICAL SYNTHESIS HAS BEEN PERFORMED AT CARBON ROD ELECTRODES IN A DIVIDED CELL USING A CONSTANT POTENTIAL. HIGH PRODUCT YIELD AND MILD REACTION CONDITIONS ARE IMPORTANT FEATURES OF THIS METHOD.

THE DEVELOPMENT OF NEW AND SIMPLE SYNTHETIC APPROACHES FOR FULLY USED ORGANIC COMPOUNDS FROM READILY AVAILABLE REAGENTS IS ONE OF THE MAJOR AIMS IN ORGANIC SYNTHESIS. THE MULTICOMPONENT REACTIONS (MCRS), BY VIRTUE OF THEIR CONVERGENCE, PRODUCTIVITY, FACILE EXECUTION AND GENERALLY HIGH YIELDS OF PRODUCTS, HAVE ATTRACTED MUCH ATTENTION FROM THE VANTAGE POINT OF SYNTHETIC CHEMISTRY. IN PARTICULAR, ISOCYANIDE-BASED MULTICOMPONENT REACTIONS APPLY TO THE SYNTHESIS OF VARIOUS FURAN AND FURAN DERIVATIVES. WE NOW REPORT THE RESULT OF OUR INVESTIGATIONS FOR THE REACTION BETWEEN ALKYL (ARYL) ISOCYANIDES1 AND DIALKYL ACETYLENEDICARBOXYLATES 2 IN THE PRESENCE OF ETHYL TRIFLUOROACETATE3 IN REFLUXING CH2CL2. THE ONE-POT THREE-COMPONENT CONDENSATION REACTION WAS PROCEEDED AT 38OC AND COMPLETED AFTER 24H TO AFFORD DIALKYL 5- [ALKYL (ARYL) IMINO] -2-ETHOXY-2- (TRIFLUOROMETHYL) -2, 5-DIHYDROFURAN-3, 4-DICARBOXYLATE4 IN GOOD ISOLATED YIELDS IN THE ABSENCE OF A CATALYST. THE STRUCTURE OF COMPOUNDS4A-J WAS DEDUCED FROM THEIR IR, 1H NMR, 13C NMR, 19F NMR, MASS SPECTRAL DATA AND ELEMENTAL ANALYSIS. THE PRESENT PROCEDURE HAS THE ADVANTAGE THAT NOT ONLY THE REACTION IS PERFORMED UNDER NEUTRAL CONDITIONS BUT ALSO THE REACTANTS CAN BE MIXED WITHOUT ANY ACTIVATION OR MODIFICATION.