Synthesis of the 1,2-Dihydro 1,2-Δ3−azaphosphorines

Abstract

1,2-Dihydro 1,2-Δ³? azaphosphorines were prepared by reaction of dichlorophenylphosphine with two equivalents of imines. 2-Oxo 1,2-azaphospholenes were also obtained in some cases.     

1,2-Cyclic Monoacyl-rac-Glycerothio-phosphates of Cantharidin Analogues

Mylabris,thedriedbodyoftheChineseblisterbeetle,hasbeenusedasChinesemedicineforover2000years.Itsactiveconstituent,cantharidin,hasantitumoractivitiesandcausesleukocytosis'.Thesynthesisofcyclicglycerophospholipidcontainingcantharidinanalogueshassofarnotbeenreportedinliterature.Theconjugatesofthistypearenotonlynewprodrugsofcantharidinantitumoragentsbutalsomaygeneratetwocytotoxicgroupsagainstdifferenttargetsitesinsideaneoplasticcell'.Suchtypesofcompoundsmaybeofinterestinchemistry,biochemistryandph…     

Effect of medium on the equilibrium of cationic σ- and π-complexes: interconversion of 1-pentafluorophenylthio-1,2-dimethyl-acenaphthylenium and 1,2-dimethylacenaphtylene-1,2-S-pentafluorophenylepisulphonium ions

The equilibrium of 1-pentafluorophenylthio-1,2-dimethylacenaphthylenium and 1,2-dimethylacenaphthylene-1, 2-S-pentafluorophenylepisulphonium ions in different media has been investigated by¹H and¹³C NMR spectroscopy using isotope perturbation. It has been found that this equilibrium is weakly sensitive to variation in the medium.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1057–1060, June, 1993.     

Reaction of α-carbanions of lithium acylates with 1,2-dibromoethane

The reaction of 1,2-dibromoethane with α-carbanions of lithium acylates generated from acetic, butyric, isobutyric, and capronic acids with lithium diisopropylamide has been studied. Anion-radical and anionic pathways of the products formation have been discussed.     

Studies of Electrochemical Catalytic Reduction Reactions of Tetraphenylporphinatocobalt/1,2-Dibromoethane and 1,2-Dichloroethane Systems in Nonaqueous Media

Electrochemical catalytic reactions of tetraphenylporphmatocobalt were studied in DMF and EtCl2 solutions in the presence of 1,2 dibroraoethane and 1,2-dichloroethane utilizing cyclic voltamme-try, thin-layer electrochemistry, in situ UV-visible spectroelectrochemistry and computer digital simulation methods. Homogeneous rate constants for reactions of electrogenerated Co(Ⅰ)TPP species with 1,2-dibro-moethane and 1,2-dichloroethane were determined as 1. 2×103 and 5 mol-1 · dm3 × s-1, respectively. Neither alkylation nor degradation of CoTPP was observed.     

An efficient synthesis of substituted benzene-1,2-dicarboxaldehydes

Substituted-benzene-1,2-dicarbaldehydes were synthesized by the reaction of substituted-1,2-bis(dibromomethyl) benzenes with fuming sulfuric acid,followed by hydrolysis. The yields were signifi-cantly improved by introducing solid sodium bicarbonate into the reaction mixture before hydrolysis and workup.     

Regioselective etherification of 1,2-O-isopropylidene-4,6-di-O-benzyl myo-inositol

During the etherification of 1,2-O-isopropylidene-4,6-di-O-benzyl myo-inositol, the specific regioselectivity on 3- or 5-hydroxyl group was showed to be determined by the nature of the O-alkylating agents used. As demonstrated by MM and MNDO calculation, the regioselectivity of the reaction mentioned can be rationalized by steric and/or electronic effect.     

Synthesis and Conformation of cis-1,2-Disubstituted Cyclododecene

Eight 1,2-disubstituted cyclododecenes were synthesized from a-alkoxycarbonyl-cyclododecanone and alkyl chloroformate. Their configuration and conformation determined by IR, NMR spectroscopy and X-ray diffraction analysis showed that the carbon-carbon double bond of all of the synthesized compounds has cis-configuration, and the ring skeleton of their preferred conformation is [lene2333] in solid, and they may adopt two different [lene2333] conformations, which exist in a dynamic equilibrium in solution.     

Reactions of 1,2-diaminobenzimidazoles with β-dicarbonyl compounds

The reactions of 1,2-diaminobenzimidazoles with β-dicarbonyl compounds give 1,2,4-triazepino [2,3-a]benzimidazole and pyrimido [1,2-a]benzimidazole-derivatives.     

Synthesis and Cleavage Studies of a 1,2-Dioxolane-type Peroxide

A [1,2]dioxolane-type peroxide was synthesized and tested for its cleavage behavior with Fe^2 -cysteinate as a simple model of biological redox species. No S-alkylation product was observed.     

An approach to the synthesis of 1,2λ-azaphosphinines

A novel approach to 1,2λ⁵-azaphosphinines has been elaborated. Aminophosphonium chlorides bearing a β-dialkylaminocrotonic nitrile residue react with N,N-dimethylformamide dimethylacetal to afford 1,2λ⁵-azaphosphinines.     

New transformation of α-acetylenic ketones under the action of 1,2-diaminoethane

A reaction of 3-aryl-1-(3,4,5-trimethoxyphenyl)prop-2-yn-1-ones with 1,2-diaminoethane in boiling dioxane leads to 2-aryl-4,5-dihydro-1H-imidazoles and 1-(3,4,5-trimethoxy-phenyl)ethanone.     

Mechanism of 1,2-shift through π-complex transition state

A systematic calculation of the potential curves or surfaces for 1,2-shift has been realized by using MNDO or other models in MOPAC programs. By referring to the previous authors' viewpoints, the 1,2-shift can be divided into two categories. 1,2-electron-deficient shift is that the electronic configuration of the atom which accepts the migrating group is a cation or an electron-deficient atom, and 1,2-anion shift is the one that the accepted atom of the migration group is a negative ion. In terms of the experimental facts and the calculation of the potential surfaces, in electron-deficient shift such as Beckmann or Baeyer-Villiger rearrangement, the migration occurs through a transition complex formed between the 7i-bond and the cation or electron-deficient migrating group, but in anion shift such as Wittig or Stevens rearrangement, the electron pair in it-orbit excites at first to π* orbit, and then the migration occurs through the new formed complex between the anion migration group and the vacant rc     

Electrochemical synthesis of 1,2-disilylethanes from α-silylacetic acids

The synthesis of 1,2-disilylethanes [R(1)R(2)R(3)Si(CH(2))(2)SiR(1)R(2)R(3)] is usually conducted by using noble metal reagents or catalysts. This work describes a new electrochemical synthetic method for their preparation in good yields by oxidation of α-silylacetic acids at Pt anodes (Kolbe electrolysis). Most of the reported synthesized 1,2-disilylethanes in this work are unknown.     

Reactions of Lithium Acylates α-Carbanions with 1,2-Diiodoethane

Russian Journal of General Chemistry - The interaction of lithium acylates α-carbanions (obtained via metallation of acetic, butyric, and isobutyric acids with lithium diisopropylamide) with...     

Effect of EtOH on the E-lodohydroxylation of 1,2-Allenylic Sulfoxides with l2

The E-iodohydroxylation of 1,2-allenylic sulfoxides with I2 in the presence of EtOH afforded 3-phenylsulfinyl-2-iodo-2(E)-alkenols in good yields and regio/stereo-selectivities under very mild conditions.     

Chiral oxetanes from sugar lactones: Synthesis of derivatives of 3,5-anhydro-1,2-O-isopropyl-α-D-glucuronic acid and of 3,5-anhydro-1,2-O-isopropyllidene-β-L-iduronic acid

Ring contraction reactions of triflates of α-hydroxy-γ-lactones provide an approach to the synthesis of chiral polyfunctionalised oxetanes from sugars. Treatment of 1,2-0-isopropylidene-5-0-trifluoromethanesulphonyl-α-D-glucuronolactone with benzylamine or with potassium carbonate in methanol gave ring contraction reactions to form oxetanes in good yield.     

Effect of EtOH on the E-Iodohydroxylation of 1,2-Allenylic Sulfoxides with I_2

Allenes are a class of versatile compounds for or-ganic synthesis.1,2 Recently we have observed the highly selective E-iodohydroxylation of 1,2-allenylic sulfox-ides3,4 affording E-3-phenylsulfinyl-2-iodo-2-alkenols in high yields.5 The reaction of substituted 1,2-allenyl phenyl sulfoxides was usually carried out at r.t. while that of 1,2-propadienyl phenyl sulfoxide should be conducted at 55 ℃. In addition, it should be noted that the stereoselectivity of this reaction was determined by the…     

The Study of Alcoholysis of 1,2-Thiazetidine-1,1-dioxide with Quantum Chemical Method

The alcoholysis mechanism of 1,2-thiazetidine-1,1-dioxide with methanol, in which the relatively stable product is sulfonate ester, has been investigated by quantum chemical method. Our calculations indicate the reaction for alcoholysis of 1,2-thiazetidine-1,1-dioxide proceeds via two possible mechanisms: concerted and stepwise. In the stepwise mechanism, two possible reaction pathways can be followed while only one possible reaction pathway can be followed in the concerted mechanism.