Phosphonates Containing Sulfur and Silicon: New Stereochemical and Mechanistic Aspects

Abstract

Synthesis, reactivity and conformation of cyclic S,S-thioacetals of formylphosphonates are described. The chemistry of α-trimethylsilyl-α-methylthiometanephosphonate is briefly discussed.     

Synthese et Etude Conformationnelle Par RMN (1H, 13C, 31P) et DFT des Cycloalcoxyphosphinallenes et des Hydrazones β-Cycloalcoxyphosphonatees

Abstract

The addition of hydrazine and its derivatives to cycloalkoxyphosphinallenes leads to β-(5,5-dialkyl-2-oxo-1,3,2-dioxaphosphoranyl)-hydrazones in good yields. The structure of the obtained compounds were elucidated by the NMR (¹H, ¹³C, ³¹P) spectroscopy and density functional theory (DFT) calculations at B3LYP/6-311++G (2d, 2p) level of theory.     

Synthesis of Some Pyrazolo[3, 4]pyrimidine Derivatives for Biological Evaluation

Abstract

A novel β -enaminonitrile of 1-(6-p-tolyl-pyridazin-3-yl)-pyrazole derivative 2 was formed using (6-p-tolyl-pyridazin-3-yl)-hydrazine ( 1 ) and 2-ethoxymethylenemalononitrile. The β-enaminonitrile derivative 2 was in turn used as a precursor for the preparation of pyrazoles ( 4 , 6 ), pyrazolo[3, 4-d]-pyrimidines ( 3 , 7–12 ) and pyrazolo[4, 3-e][1,2,4]triazolo[4,3-c]pyrimidine ( 13 ). Also, N- and S-acyclic nucleosides 14 and 15 were prepared. Some of the prepared products showed potent antimicrobial activity.     

BiCl3 Catalyzed Thiolyzation Reaction of 1,2-Epoxides with Diaryl Disulfides in the Presence of Zinc Powder and Ionic Liquid

A new and efficient method has been developed for the regio- and chemoselective synthesis of β -hydroxysulfides with the ring-opening reaction of 1,2-epoxides by diaryl disulfides and zinc powder in the presence of a catalytic amount of BiCl ₃ in molten tetrabutyl phosphonium bromide as an ionic liquid.     

ACTION DES CYANOARYLIDENES ACTIVES SUR LES β -CETO- δ -CARBETHOXYPHOSPHONATES ET PHOSPHINEOXYDES: SYNTHESE DE 2-AMINO-6-(PHOSPHONOMETHYL)-4H-PYRANES

The reaction of β-keto-δ-carbethoxyphosphonates and phosphineoxides 1 with active cyanoarylidenes 2 in basic conditions provides a convenient access to the new 2-amino-6-(phosphonomethyl)-4H-pyranes 3. The reaction is found to be highly regioselective. The structure of all obtained products is confirmed by NMR ( ¹ H, ³¹ P, ¹³ C), IR spectroscopy, and in some cases by mass spectrometry.     

Immobilization of β-galactosidase on Polystyrene Microspheres Attached L-Alanine

This study investigated the properties of immobilized β-galactosidase on polymeric beads having Schiff base. Polystyrene microspheres attached L-Alanine (FMPS-Ala) was synthesized from (4-formyl-3-methoxyphenoxymethyl)polystyrene (FMPS) and L-alanine by condensation. A coordinasyon polymer involving Ni²⁺(FMPS-Ala-Ni) was produced with the template method and characterized. β-galactosidase was immobilized onto the (FMPS), (FMPS-Ala) and (FMPS-Ala-Ni) complexes via covalent bonds. The Km/Vmax values were calculated as 0.343 mM/0.0259 mM min^?1for free β-galactosidase and 0.104 mM/0.0126 mM min^?1, 0.0617 mM/0.0417 mM min^?1and 0.210 mM/0.0287 mM min^?1for β-galactosidase immobilized to the (FMPS), (FMPS-Ala) and (FMPS-Ala-Ni) supports, respectively. The storage stability of (FMPS-Ala-Ni) was determined to be higher than that of the (FMPS) and (FMPS-Ala) polymers.     

Reaction of [HO(CH2)3]3P with α,β-Unsaturated Ketones Containing a Phenylpropanoid Backbone

Abstract

Interaction of 3,4-(MeO)₂-benzylideneacetone with [HO(CH₂)₃]₃P (THPP) was studied in CD₃OD by NMR to compare reactivity of a phenylpropanoid α,β-unsaturated ketone with a corresponding α,β-unsaturated aldehyde. In the presence of HCl, both the ketone and a related cinnamaldehyde first establish an equilibrium with the product formed by nucleophilic attack of the THPP at the C?O bond, [ArCH?CHCX(OD)PR₃]⁺Cl^?(X?H or CH₃, Ar?Ph or 3,4-(MeO)₂C₆H₃). The ketone salt then slowly transforms into [R₃PCH(Ar)CH(D)C(O)CD₃]⁺Cl^?, the phosphonium product of nucleophilic attack of THPP at the C?C bond, whereas the final product from the aldehyde is the (α-ether)phosphonium chloride [ArCH?CHCH(OCD₃)PR₃]⁺Cl^?. In aqueous media, in the absence of HCl, 4-HO-benzylideneacetone, which is similar to a lignin-type, α,β-unsaturated aldehyde model compound, interacts with THPP to afford a stable phosphonium zwitterion, in contrast to the previously studied aldehyde model, which forms dimeric, bisphosphonium products.     

Synthesis of Phosphorylated Enaminoketones and Their Application in the Preparation of Trifluoromethyl-Functionalized 2-Phosphonopyrroles

Abstract

New trifluoromethyl-functionalized 2-phosphonopyrroles were obtained by 5-exotrig cyclization of trifluoromethyl and phosphonyl functionalized enaminoketones.

GRAPHICAL ABSTRACT      

Three-Component Reaction of β-Ketosulfone,Formaldehyde, and Thiol or Thiophenol in Water

Abstract

A three-component reaction of β-ketosulfone, formaldehyde, and thiol or thiophenol was developed. The reaction was performed in pure water under a catalyst-free condition, and the corresponding Mannich-type thioethers were obtained in good to excellent yields. Finally, a one-pot stepwise four-component reaction of sodium benzenesulfinate, α-bromoketone, β-ketosulfone, and thiophenol was also developed.     

Diverse Reactions of Sulfonyl Chlorides and Cyclic Imines

Abstract

Although alkanesulfonyl chlorides react with linear imines to give rise to β-sultam derivatives, in this study, they were reacted with various cyclic imines, including 1-pyrroline, oxazoline, 5,6-dihydro-4H-oxazines and thiazines, 4,5-dihydro-3H-benzo[c]azepine, and 3,4-dihydroisoquinoline, to produce diverse products instead of β-sultam derivatives. The results indicate that alkanesulfonyl chlorides react with cyclic imines to generate N-alkanesulfonyl cyclic iminium ions, which are attacked by nucleophiles, such as water and chloride anion, in the reaction systems, affording addition products. The iminium intermediates cannot undergo a ring closure to form β-sultam derivatives. Arenesulfonyl chlorides showed similar behavior when they reacted with cyclic imines. The scope and limitation of the reaction between sulfonyl chlorides and imines were investigated.

GRAPHICAL ABSTRACT