Copper‐Catalyzed Coupling of Oxime Acetates with Sodium Sulfinates: An Efficient Synthesis of Sulfone Derivatives

Sulfone derivatives are important synthetic intermediates. However, the general method for their preparation is through traditional coupling reaction: the alkylation of sodium sulfinates with phenacyl halides. Based on our previous work on sodium sulfinates and oxime acetates, we herein report a novel method for sulfone derivatives by oxidative coupling with sodium sulfinates and oxime acetates using copper as catalyst. The sulfonylvinylamine products could be formed in excellent yields. Upon hydrolysis by silica gel in CH₂Cl₂, β‐ketosulfones could also be efficiently constructed. Various sulfonylvinylamines and β‐ketosulfones were obtained in good to excellent yields under the optimized reaction conditions. Mechanistic studies indicated that this transformation involved copper‐catalyzed N? O bond cleavage, activation of a vinyl sp² C? H bond, and C? S bond formation. The oxime acetates act as both a substrate and an oxidant, thus the reaction needs no additional oxidants or additives.     

Synthesis of carbohydrate-derived (Z)-vinyl halides and silanes: Samarium-promoted stereoselective 1,2-elimination on sugar-derived α-halomethylcarbinol acetates

A general and highly selective method for the synthesis of carbohydrate-derived (Z)-vinyl halides and silanes is described. This reaction takes place through a β-elimination process of sugar-derived α-halomethylcarbinol acetates promoted by samarium diiodide. Starting materials have been easily prepared in two steps consisting in an initial addition of halomethyllithium compounds to the corresponding galactose-derived aldehyde, followed by acetylation. A mechanism that explains both the formation of (Z)-vinyl derivatives and its selectivity is proposed. Finally, the synthetic usefulness of these compounds has been applied in cross-coupling reactions with ethynyl benzene towards the formation of selected enyne derivatives.     

Analysis of organomercuric species in soils from orchards and wheat fields by capillary gas chromatography on-line coupled with atomic absorption spectrometry after in situ hydride generation and headspace solid phase microextraction

A convenient procedure for the determination of organomercuric compounds in soils from orchards and wheat fields is described based on the aqueous derivatization of the polar organomercuric halides in 0.1 M HAc-NaAc (pH 4) buffer into their hydrides by addition of 1 mL of 6% KBH₄ with subsequent headspace solid phase microextraction (SPME) of the volatile derivatives. The volatile derivatives are separated by gas chromatography (GC) with a Supelco SPB-1 capillary column and on-line detected by electric heated quartz furnace atomic absorption spectrometry (AAS). The relative standard deviations for ten replicate measurements are 2.1%, 2.8% and 3.5% for methyl-, ethyl- and phenylmercury with absolute detection limits of 16 ng, 12 ng and 7 ng, respectively. This method is applied to the analysis of organomercuric compounds in soil samples and 0.04–0.64 μg/g of organomercuric species are detected in soils from different sites. The recoveries after standard addition are between 93–106%.     

One‐Pot Syntheses of 2‐(2‐Sulfanyl‐4H‐3,1‐benzothiazin‐4‐yl)acetic Acid Derivatives via Reactions of 3‐(2‐Isothiocyanatophenyl)prop‐2‐enoic Acid Derivatives with Thiols or Sodium Sulfide

Two efficient methods for the preparation of 2‐(2‐sulfanyl‐4H‐3,1‐benzothiazin‐4‐yl)acetic acid derivatives 3 under mild conditions have been developed. The first method is based on the reaction of 3‐(2‐isothiocyanatophenyl)prop‐2‐enoates 1a – 1c with thiols in the presence of Et₃N in THF at room temperature, leading to the corresponding dithiocarbamate intermediates 2 , which underwent spontaneous cyclization at the same temperature by an attack of the S‐atom at the prop‐2‐enoyl moiety in a 1,4‐addition manner (Michael addition) to give 2‐(2‐sulfanyl‐4H‐3,1‐benzothiazin‐4‐yl)acetates in one pot. The second method involves treatment of 3‐(2‐isothiocyanatophenyl)prop‐2‐enoic acid derivatives 1b – 1d with Na₂S leading to the formation of 2‐(2‐sodiosulfanyl‐4H‐3,1‐benzothiazin‐4‐yl)acetic acid intermediates 5 by a similar addition/cyclization sequence, which are then allowed to react with alkyl or aryl halides to afford derivatives 3 . 2‐(2‐Thioxo‐4H‐3,1‐benzothiazin‐4‐yl)acetic acid derivatives 6 can be obtained by omitting the addition of halides.     

Analysis of organomercuric species in soils from orchards and wheat fields by capillary gas chromatography on-line coupled with atomic absorption spectrometry after in situ hydride generation and headspace solid phase microextraction

A convenient procedure for the determination of organomercuric compounds in soils from orchards and wheat fields is described based on the aqueous derivatization of the polar organomercuric halides in 0.1 M HAc-NaAc (pH 4) buffer into their hydrides by addition of 1 mL of 6% KBH₄ with subsequent headspace solid phase microextraction (SPME) of the volatile derivatives. The volatile derivatives are separated by gas chromatography (GC) with a Supelco SPB-1 capillary column and on-line detected by electric heated quartz furnace atomic absorption spectrometry (AAS). The relative standard deviations for ten replicate measurements are 2.1%, 2.8% and 3.5% for methyl-, ethyl- and phenylmercury with absolute detection limits of 16 ng, 12 ng and 7 ng, respectively. This method is applied to the analysis of organomercuric compounds in soil samples and 0.04–0.64 μg/g of organomercuric species are detected in soils from different sites. The recoveries after standard addition are between 93–106%.     

Nucleotide derivatives of biological importance. 8. Synthesis of adenosine triphosphate (ATP) analogs

Analogues of ATP belonging to the following classes have been prepared: N⁶-monoacyl derivatives, N⁶-mono- and -di-alkyl derivatives, 6-deamino-ATP, 8-bromo-ATP, 8-amino-ATP and ATP-N(1)-oxide. With the exception of the last compound, the corresponding AMP derivatives have been used as intermediates in these preparations.     

Preparation of N-Alkylphtalimides Assisted by Solid-Liquid Phase-Transfer Systems

N-Alkylphtalimides are intermediates in the synthesis of primary amines¹ and are generally prepared from potassium phtalimide and alkyl halides in anhydrous polar aprotic solvents such as dimethylformamide.² Recently, N-alkylation of potassium phtalimide has been achieved from alkyl halides and methanesulfonates in toluene in the presence of hexadecyltributylphosphonium bromide³.     

Synthesis and spectroscopic properties of N-azolylpropanamides

Fourteen N-azolylpropanamides have been prepared by Michael addition of azoles on acrylamide. The compounds have been fully characterized by IR and by ¹H and ¹³C-nmr. The isolated compounds are the most stable derivatives; kinetic compounds were observed but could not be isolated.     

Methylmercuric halide-halide complexation in ethanol solution

The formation constants for CH₃HgCl₂^? at 26°C (0.31 l/mole), and for CH₃HgBr₂^? at 26°C (0.94 l/mole) and at 60°C (0.70 l/mole) in ethanol solution have been determined from the variation of Hg NMR chemical shift (by INDOR) with composition of methylmercuric halide-lithium halide solutions. These data have been employed in a reexamination of the “one-anion” and “two-anion” catalysed reactions of mercuric bromide with alkylmercuric bromides.     

The Forgotten Carbonyl Reaction: Chloroacetylation and Bromoacetylation of Carbonyl Compounds

Halomethyl acetates ( 3 ) could be prepared from aliphatic, α,β‐unsaturated and aromatic aldehydes, as well as from alicyclic ketones with high yields in simple one‐pot reactions. Very often, the products didn't have to be purified and could directly be used for synthetic purposes after evaporation of the solvent. Obviously, the ‘bad reputation’ of the reaction in the literature stemed from the fact that the reactions didn't take place under the best conditions. Carbonyl compounds ( 1 ) and acyl halides ( 2 ) form equilibria which are completely on the side of the halomethyl acetates ( 3 ) at room temperature (starting with aliphatic and most aromatic aldehydes) and which can be strongly influenced by the reaction parameters. It is crucial to work at low temperature in apolar solvents and to remove (or deactivate) the catalyst before workup. Reactions may be realized with or without solvents. Side reactions were observed with formaldehyde and acetaldehyde but, with exception of formaldehyde, could be reduced close to zero (see Fig. 5). By‐products were essentially avoided if the reaction took place in apolar solvents and with a local excess of acetyl chloride. In many cases clean products were available which could directly be used for synthetic purposes. Halomethyl acetates ( 3 ) are bifunctional carbonyl derivatives with two different leaving groups, whose preparative advantages have been useful for the synthesis of various pentafulvenes, but were especially important for preparing unstable parent fulvenes and fulvalenes.     

Photocyclisation of 2-Methoxyphenyl Pheynil Ethers

The Photoinduced resotions of diaryl others have been extensively studied and are found to encompass rearrangesent to the 2- and 4-hydraxybiphanyl derivatives and other bond clesvage loading ultimately to the corresponding phenol and benzene derivatives.^2–6 On one occasion dibenzofuran was reparted as a photoproduct of diphenyl other⁷ but this observation has not been supported by latter work^4,8,9. In contrast 2-Ahlorophenyl 1-naphthyl other has been Shown to undergo efficient photodahydrohalogenstion to form benzo[b]naphtho[2,1-d]furan⁹.     

Synthesis of Glycosyl Esters and Glycosyl Hemiacetals From Methylthioglycosides

ABSTRACT

Glycosyl esters constitute a widespread family of natural products such as anti-tumor agents,¹ antibiotics,² terpenoid glycosides,³ plant pigments⁴ and other substances.⁵ It has been shown that aromatic carboxylic acids are metabolized by humans as glycosyl esters,⁶ and D-glucopyranosyl fatty acid esters were found to inhibit the growth of leukemia cells⁷ and plant growth.⁸ The synthesis of a prodrug in the g form of a glycosyl ester has been reported.⁹ In synthetic chemistry glycosyl acetates are frequently used glycosyl donors in Lewis-acid catalyzed glycosylation reactions¹⁰ and other transformations.¹¹     

A Conventent Synthesis of Functonalised Heterocuclic Enamines from Alpha-Thioiminium Salts and Active Methylene Compounds Under Solid-Liquid PTC Conditions

Functionalised enanines constitute a category of synthetic intermediates useful in carbon, carbon bond formation reactions and have been procured through a variety of condensaticn and extrusion reactions.¹ In one approach active methylene compounds have been condensed with lactin thioethers in the presence of a base at relatively higher temperature.^2,3 In view of our interest in the synthesis of function alised enamines through sulphur extrusion reactions⁴, we have studied the title reaction under non-hydrolytic solid-liquid PTC using solid KF(base)/TEBA(catalyst). A recent report⁵ on the sulphur extrusion of α -thio-iminium salts and their reactions with active methylene compounds prompts us to report our results.     

Neryl- and geranyltriethylammonium halides in the allylation of sodium diethyl malonate. The effect of the leaving group of the allylating reagent on the selectivity of the reaction

In the absence of catalysts,N-neryl-andN-geranyltriethylammonium halides can allylate sodium diethyl malonate to give terpene malonate derivatives. Using the above-mentioned ammonium salts, geranyl and neryl acetates, geranyl ethyl carbonate, and geranyl diethyl phosphate as examples, it has been shown that with Pd⁰ and Pd^II catalysts, the selectivity of the formation of neryl-, geranyl-, and linalylmalonates can be governed by varying the leaving group of the allylating agent.Translated fromIzyestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 270–272, February, 1994.     

Syntheses of 4‐(5‐oxo‐1,2,4‐triazol‐3‐yl)‐sydnones and 4‐(4‐arylamino‐5‐oxo‐1,2,4‐triazol‐3‐yl)‐sydnones from Sydnone Derivatives and Their Fragments

4‐(5‐oxo‐1,2,4‐triazol‐3‐yl)‐sydnones 11 and 4‐(4‐arylamino‐5‐oxo‐1,2,4‐triazol‐3‐yl)‐sydnones 13 have been obtained from a‐chloroformylarylhydrazine hydrochloride 2 . Moreover, the intermediates, including 3, 4 , 9 and 10 , in this study are synthetically informative and valuable. It is also noteworthy that three reactants, 1, 2 and sydnonecarbaldehydes, were prepared from sydnone derivatives and their fragments. The oxidative cyclizations of sydnonecarbaldehyde semicarbazones 9 and carbazones 10 with two different oxidizing agents (Cu(ClO₄)₂ and Fe(ClO₄)₃) have been extensively examined. The reaction time and the yields of cyclizations were affected by the substituents of semicarbazones 9 and carbazones 10.     

Polyethylene Glycols as Solvents for Anionic Activation: Synthesis of Thioacetates by Means of Potassium Thioacetate in Polyethylene Glycol 400

Recently, polyethylene glycols (PEGS) of various molecular weights have been proposed as solvent promoters for various reactions ^{1, 2}. We wish to report on the use of PEG 400 as solvent for the anionic activation of potassium thioacetate, which could be used for the preparation of alkyl and benzyl thioacetates from the corresponding halides or alcohol derivatives. The method can be synthetically significant, since from thioacetates the corresponding thiols can be easily prepared under a variety of mild conditions ³.     

Some new polymeric semiconductors

This paper deals with some new methods for synthesis of the polymeric semiconductors by conjugated reactions and also with electrophysical properties of the polymers. Elimination of hydrogen halides from α,β-dihalo derivatives by bases (calcium oxide or tertiary amines) yields polymers with conjugated bonds. The reaction proceeds at 200–300°C. under atmospheric or elevated pressures, acetylenes being the intermediates. α,β-Dihalo compounds with calcium carbide above 150°C. produce polyacetylenic copolymers by elimination of two moles of hydrogen halide, also by generating acetylene from calcium carbide. The identical reaction (elimination of water) was observed between carbonyl compounds and calcium carbide. Elimination of water from monoand bifunctional phenols in the presence of zinc chloride under pressure above 200°C. yields polyphenylenes and polyhydroxyphenylenes, dehydrobenzene (benzyne) and hydroxybenzyne being intermediates. The polyhydroxyphenylenes prepared have a degree of polymerization from 4–5 to several thousand and are of interest as intermediates for thermostable resins, inhibitors etc. Linear polycyanamide and polycyanic acid were first prepared by polycondensation of urea with ammonium bicarbonate in the presence of zinc chloride. Analogous polymers were obtained from the ring-opening polymerization of melamine and cyanuric acid. The polymers show good semiconductor and ion-exchange properties. Polycondensation of ketones with ammonium bicarbonate also gave conjugated polymers. Thus, organometallic polymers were prepared from acetyl- and diacetyl ferrocene. We have also studied electrophysical, magnetic, and catalytic properties of the conjugated polymers prepared by the new methods. The electrical conductivity of the best specimens ranged from 10^?3 to 10^?6 ohm^?1 cm.^?1; the number of electrons unpaired was 10¹⁸–10¹⁹ spins/g.     

Application de la RMN du 13C a la determination de la configuration de centres quaternaires en serie alicyclique et hydrate de carbone a chaine ramifiee

Configurational assignments to quaternary centres of 2-(l,3-dithianyl) branched-chain carbohydrates, important intermediates for the synthesis of carbohydrate-containing antibiotics, have been made through natural abundance ¹³C NMR spectroscopy. Configurations of quaternary carbons in 21, 24 and 26 were assigned by comparison with ¹³C spectra of structurally-related alicyclic derivatives 1–16.     

Structure-Activity Relationship in Ambergris-Type Woody Odorants possessing a hydronaphthalene skeleton

A series of methyl hydronaphthyl alcohols, formates, acetates, and ketones were prepared and their odour properties evaluated. Minor structural changes, even opposite to the osmophoric group, were found to have major effects on the odour. ¹³C? NMR shift assignments of the hydronaphthyl derivatives are presented.     

Versatile asymmetric synthesis of the kavalactones: first synthesis of (+)-kavain

[reaction: see text] Three asymmetric pathways to the kavalactones have been developed. The first method is chiral auxiliary-based and utilizes aldol reactions of N-acetyl thiazolidinethiones followed by a malonate displacement/decarboxylation reaction. The second approach uses the asymmetric catalytic Mukaiyama additions of dienolate nucleophile equivalents developed by Carreira and Sato. Finally, tin-substituted intermediates, prepared by either of these routes, can serve as advanced general precursors of kavalactone derivatives via Pd(0)-catalyzed Stille couplings with aryl halides.