Thiocarbonyl Compounds Reactivity with Organosilanes: Functionalization with α-Heterosubstituted Silyl Nucleophiles

Abstract

The reaction of different thioderivatives with several α-heterofunctionalized silyl compounds leads to the products deriving from a regiospecific attack on the sulfur atom of the C=S moiety, affording the corresponding adducts differently functionalized.     

Synthesis and Characterization of Two New Organically Templated Open-framework Uranium Phosphites

1 INTRODUCTION Uranium-based open-framework materials are the subject of significant investigation because of their relevance to radioactive waste management, ura- nium geochemistry and possible applications in ion exchange, catalysis, etc[1]. The crystal chemistry of hexavalent uranium is rich in structure style due to the high coordination numbers (six, seven, or eight) accessible to U6 and the polarized distribution of bond strengths within uranyl polyhedra. The area of metal phospho…     

Reaction of Trialkyl Phosphites with α,β-Unsaturated Carbonyl Compounds

Abstract

Reaction of trialkyl phosphites 1 with α,β-unsaturated oxo-compounds 2 gives oxaphospholenes 3 or/and two types of Arbuzov products, γ-keto-phosphonates 4 and alkyl-enol-ethers 5.     

Products in the Reactions of Trialkyl Phosphites with α-Halogeno-acetophenones in Alcoholic Media

Abstract

α-Hydroxyphosphonates are formed, in addition to vinyl phosphates and dehalogenated ketones, in the reactions of trimethyl phosphite (in methanol) or triethyl phosphite (in ethanol) with variously substituted α-chloro, α-bromo, and α,α,-dichloro-acetophenones. Tri-isopropyl phosphite in propan-2-ol gives only the vinyl phosphate. Ketophosphonates are not detectable amongst the reaction products under the conditions used. Trends in product composition can be correlated with the leaving ability of halogen, substituent effects, structure of the phosphite, and reaction temperature. Reactant ratios may also influence the product composition. The reactions of trimethyl phosphite in methanol with 4-nitro-α-chloroacetophenone, or α,α-dichloroacetophenones yield the dehalogenated α-hydrogxyphosphonates in addition. In the case of the 4-nitro derivative, this product cannot be accounted for by reaction of the phosphite with dehalogenated ketone (4-nitroacetophenone). Dehalogenation of the first-formed α-hydroxyphosphonate was, however, shown to occur under reaction conditions and appears to require the removal of positive chlorine, followed by protonation. Reactions of the α,α-dichloroacetophenones were similar to those of the α-chloroacetophenones, giving the corresponding chlorovinyl phosphate, α,α-dichloro-α-hydroxyphosphonate, and monodehalogenated ketone(i.e. α-chloroacetophenone); the latter was not however detected as it reacted further with excess phosphite to give the expected products as described above. Possible mechanisms for the various reactions are discussed. The ¹H and ¹³C nmr spectra of the α-hydroxy-phosphonates show magnetic non-equivalence of the two alkoxy groups, attributed to restricted rotation about the P-C bond as a result of intramolecular hydrogen-bonding.     

Cloud Points of Water—soluble Polyether Phosphites and Their Application in the Biphasic Hydroformylation of Higher Olefins

Wate-soluble polyether phosphites alkyl polyethylene glycol ophenylene phosphite(APGPPS)were alcoholysis of phosphorus chloride with plyoxyethylene alkyl ether.With appropriate HLB(hydrophile-lypophile balance),the phosphites possess clear cloud points below 100℃，Addition of some inorganic salts decreases cloud points of the phosphites.When the phosphiites have long polyether chain binding to short-chain alkyl group,their cloud points could be extrapolated from figure of dependece of cloud points on addition of inorganic salts.Utilizing octylpolyglycol-phenylene-phosphite(OPGPP)(APGPP,R:Octyl)/Rh complex formed in situ as catalyst,over 90% conversion of 1-decene was obtained ,avoiding the limitation of water insolubility of substrates.Preliminary results indicated that micellar catalysis and thermoregulated phase-transfer catalysis(TRPTC)coexist in the reaction system.Below cloud point,micellar catalysis induced by plyether phosphites may be existed.When temperature is increased to above cloud point of the phosphies,this reaction works mainly in TRPTC.The catalysts could be easily spearated by simple decantation,but followed by considerable loss in activity after three successive reaction runs.Preliminary results indicated hydrolysis of OPGPP happened during the reaction.which may explain for the bad loss in activity.The catalyst was reused up to seven times with-out clear decrease in activity when OPGPP/Rh ratio was increased to 50.     

α-Styrylarsines

The compounds (1) formed by the addition of arsenic trichloride to phenylacetylenes contain several reactive sites and hence are useful synthetic intermediates. We have prepared these compounds in high yield by this route and have examined certain of their properties. The vinylic chlorine, generally stable to reduction, may be quantitatively and readily reduced using a lithium aluminium hydride-lithium hydride mixture. The chlorine atoms attached to arsenic are extremely reactive and readily hydrolysed and hence precautions must be taken to exclude atmospheric moisture from the reaction system. The chlorine atoms will also react on treatment with a Grignard reagent to give the diphenylstyrylarsine (2)     

α-KETOSULFONES

Abstract

Since the turn of the last century a great many attempts have been made to synthesize the interesting class of α-ketosulfones, the connecting links between the known α-diketones and α-disulfones. The first publications indicating successful syntheses proved to be science fiction only. The cyclic sulfonyl carbamates synthesized by R. J. Gaul and W. J. Fremuth in 1961 are the first compounds with authentic α-oxosulfonyl structure. Later on, open-chained sulfonyl carbamates I as well as the corresponding sulfonyl thioformates II have been synthesized by A. Senning and co-workers; the related sulfonyl formates III could be synthesized recently by D. H. R. Barton and co-workers as well as by G. Ferdinand and K. Schank using two entirely different routes.     

Ionic liquid-promoted Wagner-Meerwein rearrangement of 16α,17α-epoxyandrostanes and 16α,17α-epoxyestranes

Ionic liquids 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim](+)[PF(6)](-)) and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim](+)[BF(4)](-)) were found to promote an unusual Wagner-Meerwein rearrangement of steroidal 16α,17α-epoxides leading to unnatural 13-epi-18-nor-16-one derivatives as the main products. These compounds were isolated in good to excellent yields. 16α-Hydroxy-Δ(13)-18-norsteroids, the results of the usual rearrangement, were obtained as minor components of the reaction mixtures. The ionic liquid [bmim](+)[PF(6)](-) was shown to induce C-ring aromatization of 16α,17α-epoxyestranes due to the formation of HF, the hydrolysis product of [PF(6)](-). Increasing amounts of HF and [PO(2)F(2)](-) were detected by (19)F and (31)P NMR when the ionic liquid was reused. The structures of the steroidal products, 16-oxo-18-nor-13α-steroid derivatives, 16α-hydroxy-Δ(13)-18-norsteroids, and C-aromatic compounds were determined by two-dimensional NMR techniques and high-resolution mass spectrometry (HRMS). The ionic liquids were recirculated efficiently.     

α,α-Difluoro-α-phenylsulfanyl-α-trimethylsilylmethane as a difluoromethyl building block: A general strategy to α,α-difluoromethyl aryl ketones

The synthetic utility of α,α-difluoro-α-phenylsulfanyl-α-trimethylsilylmethane (PhSCF₂SiMe₃; 1) as a difluoromethyl building block providing a general strategy to α,α-difluoromethyl aryl ketones was demonstrated. Oxidation, by using m-chloroperoxybenzoic acid, of the readily available 1-aryl-2,2-difluoro-2-phenylsulfanyl-1-trimethylsiloxyethanes obtained from fluoride-catalyzed nucleophilic addition of PhSCF₂SiMe₃ with aromatic aldehydes followed by flash vacuum pyrolytic elimination provided α,α-difluoromethyl aryl ketones in moderate overall yields.     

α-Hydroxy- and (α-acyloxyimino)benzylphosphonates

N-Hydroxyfluorobenzimidoylphosphonates and their O-acyl derivatives are synthesized. Reaction of phosphorylated oximes with sulfinyl chloride proceeds with rearrangement and leads to synthetically prospective N-sulfonylimidoylphosphonates. By the method of ¹⁹F NMR are revealed values of σ-constants of N-hydroxy- and N-acyloxy substituted imidoylphosphonate groups.     

Investigations of the Chemistry of Alkyl Phosphites Toward Nitrogen-Containing Compounds: Efficient Approaches to α-Amino-, β-Amino-, and/or Enaminophosphonates

Abstract

In this study, we report recent investigations of the chemical reactivity of alkyl phosphites, mainly trialkyl and dialkyl phosphites, with molecules containing different nitrogen-containing compounds reported by us and other research groups over the past 25 years. Previous ground-breaking important reports are also considered. The reviewed investigations in this article are grouped according to only the type of the nitrogen-functional groups [amines (primary, secondary, and tertiary amines), imines, amides, thioamides, nitriles, isocyanates, isothiocyanates, oximes, hydrazones, diazo, and azides] and not according to the site of attack or the final products. Furthermore, the present review article focuses on the synthesis of α-amino-, β-amino-, and/or enaminophosphonates. These compounds have important roles in pharmaceutical chemistry.     

Überα,α'-Dichlordimethyläther

Ohne ZusammenfassungMit 1 Abbildung.     

Capto-Dative Acylenamines in the Reactions with Dialkyl Hydrogen Phosphites: One-Pot Transformation of α-Formylated Enamines to the Esters of N,N-Disubstituted α-Aminoacids

-Acylenamines with terminal double bond CH₂ = CH(NR₂)COMe add dialkyl hydrogen phosphites to form only the Michaelis adducts. Contrary to that hydrophosphorylation of -formylated enamines proceeds regiospecifically at C=O bond. Subsequent isomerization of the products of 1,2-addition and the cleavage of P-C bond of the intermediate -keto--aminophosphonate yields N,N-disubstituted -aminocarboxylates.     

α-烷基-α-氨基酸的合成

本文研究了八种酮在相转移催化剂存在下与氯仿和氨水的作用。一步得到α-烷基-α-氨基酸和它们的酰胺。用脂肪族甲基酮和环戊酮作原料时,仅得到α-烷基-α-氨基酸一种产物。     

6α-carboxy and 6α-carbamoyl,penicillins

Hemiacetal formation from 6α-formylpenicillins followed by oxidation has provided a series of esters of 6α-carboxypenicillins and the parent acid. Further derivatisation has afforded a 6α-carbamoylpenicillin.     

Aryl-NNO-azoxy-α-nitroalkanes

Two methods of synthesis of aryl-NNO-azoxy--nitroalkanes bearing either one or two reactive hydrogen atoms to the azoxy and nitro groups are described. These methods involve protection of the latter by easily removable groupings, those used being acetoxy-methyl and acetal fragments. The regiochemical nature of the diazene oxide groupings in aryl-NNO-azoxy--nitroalkanes obtained by oxidation of the appropriate diazenes has been established by heteronuclear NMR and x-ray structural examination. Some of the chemical properties of these diazene oxides have been examined.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 10, pp. 2400–2412, October, 1992.     

Methyl 2,6-Dideoxy-4-α-Methyl-α-D-Arabino-Hexopyranoside

Abstract

Synthesis of methyl 2,6-dideoxy-4-O-methyl-α-D-arabino-hexopyranoside (2) has been accomplished starting from readily available methyl 2-deoxy-α-D-arabino-hexopyranoside (3). The derived 4,6-dimesylate derivative 7 was simultaneously deoxygenated and hydrolysed at C-6 and C-4 with lithium aiuminatm hydride in refluxing tetrahydrofuran. subsequent methyíaíion and debenzy[icaron]ation of 8 gave the title product.     

Ab Initio Study of Prednisolone, 6α-Fluoroprednisolone, 9α-Fluoroprednisolone,and 6α,9α-Difluoroprednisolone

A theoretical study of prednisolone, 6-fluoroprednisolone, 9-fluoroprednisolone, and 6,9-difluoroprednisolone has been performed at the ab initio HF/6-31G, MP2/6-31G, and B3LYP/6-31G levels. Structural information and the electronic features of prednisolone and its derivatives and the synergistic effect of 6,9-difluoroprednisolone was examined. Contrary to the AM1 and MNDO results, we found 9-fluoroprednisolone is more stable than the 6-fluoroprednisolone. The increased corticosteroid activity of the 6,9-difluoroprednisolone is most likely due to electronic effects, mainly related to the receptor binding.