Three-component reaction between Triphenylphosphine, Acetylenic Esters and 4-hydroxycoumarin, 4-(phenylamino)coumarin, 4-hydroxyquinolin-2(1H)-one or 4-hydroxy-1-methylquinolin-2(1H)-one

Diastereoselective Synthesis of Stable Phosphorus Ylides by a Three-Component Reaction between Triphenylphosphine, Dialkyl Acetylenedicarboxylates and 3-(Arylsulfonylhydrazono)Butanoates

Protonation of the reactive 1:1 intermediate produced in the reaction between dialkyl acetylenedicarboxylates and triphenylphosphine by 3-(arylsulfonylhydrazono)butanoates leads to vinylphosphonium salts which undergo Michael addition with the conjugate base of the CH-acid to produce highly functionalised, salt-free phosphorus ylides in a diastereoselective manner and excellent yields.

An Efficient One-Pot Synthesis of 1,3,5-Substitutec-1H-Pyrazoles Derivatives

One-pot reaction between dialkyl acetylendicarboxylates and different hydrazide acids in the presence of triphenylphosphine leds to 1,3,5-substituted-1 H-pyrazoles derivatives in excellent yields. In the absence of triphenylphosphine, dialkyl acetylenedicarboxylate adds to hydrazide acids to produce dialkyl 2-(arylhydrazono)succinates were obtained in good yields.

Three-Component Reaction between Triphenylphosphine, Dialkyl Acetylenedicarboxylates and 3-(3,5-Dimethyl Pyrazol-1-yl)-3-oxo Propionitrile

Protonation of the reactive 1:1 intermediate produced in the reaction between dialkyl acetylenedicarboxylates and triphenylphosphine by 3-(3,5-dimethyl pyrazol-1-yl)-3-oxopropionitrile leads to vinylphosphonium salts which undergo Michael addition with the conjugate base of the CH-acid to produce highly functionalised, salt-free phosphorus ylides in excellent yields.

Theoretical Study, An Efficient Synthesis Route to, and Kinetic Investigation of, Stable Phosphorus Ylides Derived from Benzamide

The synthesis, theoretical study and a kinetics and mechanistic investigation are described as a one-pot condensation reaction between benzamide and acetylenic esters in the presence of triphenyphosphine to generate a novel stable phosphorus ylides. For the first time, theoretical calculations have been employed to assign the most stable isomers ( Z or E) of phosphorus ylides 4a-c by AIM and NBO theory, in which Z-4(a,b) are the more stable forms, whereas Z-4c appears as a single isomer. In these cases, the 1H, 13C and 31P NMR spectra of these ylides are consistent with the results obtained from theoretical calculations. Kinetic investigation of the new ylides was undertaken by UV. Useful information was obtained from studies of the effect of solvent, structure of reactants (different alkyl groups within the acetylenic esters), and also the concentration of reactants on the rate of reactions. The proposed mechanism was consistent with the results obtained; from the steady-state approximation, the first step ( k2) of the reaction was recognized as the rate-determining step on the basis of the experimental data.

Synthesis of Stable Phosphorus Ylides from 6-Chloro-2-Benzoxazolinone and Kinetic Investigation of the Reactions by Uv Spectrophotometry

Stable crystalline phosphorus ylides were obtained in excellent yields from the 1:1:1 addition reactions between triphenylphosphine and dialkyl acetylenedicarboxylates, in the presence of an NH-acid, such as 6-chlorobenzoxazolinone. These stable ylides exist in solution as a mixture of two geometrical isomers as a result of restricted rotation around the carbon-carbon partial double bond resulting from conjugation of the ylide moiety with the adjacent carbonyl group. To determine the kinetic parameters of the reactions, they were monitored by UV spectrophotometry. The second order fits were drawn and the values of the second order rate constant ( k2) were calculated automatically using standard equations within the program. Over the temperature range studied, the dependence of the second order rate constant (Ln k2) on reciprocal temperature was in a good agreement with the Arrhenius equation, leading to the activation energies of all reactions. Furthermore, useful information was obtained from studies of the effect of solvent, the structure of reactants (different alkyl groups within the dialkyl acetylenedicarboxylates) and also the concentration of reactants on the rate of reactions. The proposed mechanism is consistent with the results obtained and the steady state approximation, and the first step ( k2) of reaction was recognized as the rate-determining step on the basis of experimental data.