Azaiez Ben Akacha

PHOSPHO-4-PYRAZOLES. SYNTHESE ET ETUDE SPECTROGRAPHIQUE RMN 1H, 31P ET 13C

Abstract 4-Phosphopyrazoles are prepared with good yield by cyclisation of hydrazone phosphorus compounds and ethylortho formiate. The effects of substitution are investigated on the 13C chemical shifts of pyrazole ring. The magnitude of the coupling constant 1 J pc is in good agreement with the hybridization of the phosphorus atom.

OXYDES DE DIAZAPHOSPHOLINES-1,2,3: SYNTHESE ET ETUDE SPECTROGRAPHIQUE IR ET DE RMN 1H, 31P, 13C

Abstract δ5-3-dimethylamino-3-oxo-1,2,3-diazaphospholines are prepared by cyclisation of bis(dimethylami-no)phosphinallene oxides containing two electrophilic sites in position 1.3 (phosphorus atom and medium carbon allenic) with hydrazine derivatives. Mechanistic explanations of these results have been described by NMR. The IR and the 31P, 13C, 1H chemical shifts of diazaphosphollines oxides are commented.

REACTION DES O, O-DIETHYL OXO-1 ALKANEPHOSPHONATES AVEC LES DERIVES DE L'HYDRAZINE: UNE VOIE DE SYNTHESE DES HYDRAZONES α-PHOSPHONATEES ET DES HYDRAZIDES

Abstract Under the normal conditions, the reaction of hydrazine and methylhydrazine with OO-diethyl 1 oxoalkane phosphonates 1 proceeds by cleavage of the phosphorus-carbon bond and leads to the formation of diethylphosphite 2 and N-acylhydrazide 3 . A procedure has been developed for the synthesis of new primary hydrazone of OO-diethyl 1-oxoalkane phosphonates 4 . A mechanism is proposed. The structure of those compounds 4 was confirmed by NMR and IR spectroscopy.

13C NMR and 31P NMR spectral assignment of new β‐phosphonylated hydrazones

31P, 13C NMR and 1J(C,P), 2J(C,P) and 3J(C,P) coupling constants are reported. The stereochemistry (E and Z) of a series of new acyclic β‐phosphonylated hydrazones was assigned on the basis of the chemical shifts of carbons in α (C‐1) and α′ (C‐3) positions with respect to the CN moiety. Copyright

Reactivite Des α -Phosphonylketones Dans la Reaction de Gewald: Synthese de Nouveaux Derives de L′aminophosphonothiophene

The reaction of α -phosphonylketones 1 with active methylenenitriles 2 leads to phosphonoalkylidenes 3 . The reaction of compounds 3 with sulfur under basic conditions leads to the new 2-amino-4-phosphonothiophenes 4 . The structure of all obtained products was confirmed by NMR (1H, 31P, 13C) and IR spectroscopy, and in some cases by mass spectrometry.

ACTION DU REACTIF DE LA WESSON SUR LES HYDRAZONES β-PHOSPHONATEES: SYNTHESE DE Δ5-5-(METHYLENE-PHOSPHINEOXYDE)-3-THIOXO-1,2,3-DIAZAPHOSPHOLINES

Abstract β-Phosphonylhydrazone 1 are considered as reagents in heterocyclic synthesis (Pyrazoles phosphonated, Diazaphospholines oxides). In the present work, we study the reaction of hydrazones β-disubtituted phosphine oxide 1 with Lawesson reagent (L R) to lead to the 3-thioxo-1,2,3-diazaphospholines derivatives 2 . The structure of products 2 is confirmed by NMR and IR spectroscopy.

Synthese de Quelques α-Cetophosphonates Comportant des Hydrogenes Mobiles en Position α: Caracteristiques Spectroscopiques IR, RMN 1 H, 13 C, 31 P et Reactivites vis-a-vis des Amines et des Derivees de L'hydrazine

In the present work we describe the keto-enol equilibrium of some acylphosphonates 1 by means of 1 H, 13 C, 31 P NMR, and IR data which show that the enol form has E configuration. The keto/enol ratio is determined on the basis of 31 P NMR data. The reactivity of 1 with hydrazines derivatives and primary amines are reported. The structure of all compounds is determined by 1 H, 13 C, 31 P NMR, and IR.

OXYDES DE N-2-ACYL DIAZAPHOSPHOLINES-1,2,3: SYNTHESE, REACTIVITE ET ETUDE SPECTROGRAPHIQUE IR ET DE RMN 1H, 31P, 13C

Abstract The monoacylhydrazides, as well as hydrazines, react with phosphoallenic derivatives 1 to lead to the δ5-N-2 acyl 3-dimethylamino 3-oxo-1,2,3-diazaphospholine 2 . The reaction of ring opening in δ5-N-2 acyl-3-dimethylamino-3-oxo-1,2,3-diazaphospholine by different alcohols leads to the β-phosphonyl-hydrazide 3 . The structure of products ( 2 and 3 ) is further confirmed by IR, 1H, NMR, 13P NMR, 13C NMR spectra.

Synthesis and evaluation of analgesic, behavioral effects and chronic toxicity of the new 3,5-diaminopyrazole and its precursor the thiocyanoacetamide

This study aimed to explore the analgesic, antioxidant, behavioral and toxicological effects of 3,5-diaminopyrazole and thiocyanoacetamide. Caffeine was used as reference drug whose effects are known after oral treatment with an efficient dose (10mg/kg/day) for 30days. The preliminary bioassays indicated that both compounds at this dose have strong antioxidant capacities and present highly analgesic effects. The behavioral study showed an activation of the rat memory by thiocyanoacetamide. This molecule caused a phobia state to open areas in the elevated plus maze and specifically agoraphobia in the open field with a lack in the development of the exploratory capacity. 3,5-Diaminopyrazole caused memory troubles in rats that forgot the pathway to the exit from the maze, and induced an anxiety state revealed by immobility in closed arms of the elevated plus maze. All these observations were compared to the treatment by the known analgesic, caffeine, which increased the state of vigilance of the rats and developed their exploratory capacity. The chronic treatment with the investigated compounds showed no sign of toxicity with the absence of effect on the body and organ weights, blood count, kidney and liver function and histology. 3,5-Diaminopyrazole and thiocyanoacetamide have potent antioxidant and analgesic activities that are higher than caffeine with a safety profile. The chronic treatment by thiocyanoacetamide activated the memory and caused an emotional state of agoraphobia, but 3,5-diaminopyrazole caused a memory impairment and an emotional state of anxiety. Thus, the present study warrants further investigations involving these novel molecules for a possible development of new strong analgesic and antioxidant drugs which have an effect on the memory capacity.

Interactions of copper(II) and zinc(II) with chlorophyll: insights from density functional theory studies

The reaction of chlorophyll (a) with Cu2+ or Zn2+ in the presence of acetonitrile has been studied on a slightly simplified model using DFT computations of three potential processes: the substitution of the central Mg2+ cation, the chelation of the peripheral keto-ester, associated or not with deprotonation. Mg-substitution is found to be highly favored in the case of copper, whereas chelation without deprotonation is proposed to occur for zinc. It is proposed that chelation associated with deprotonation could become competitive if water is present in the reaction medium. The resulting compounds are shown to have interesting electronic properties as metal → ligand spin transfer is observed in the case of Cu2+.