Copper-catalyzed domino reaction between terminal alkynes,isocyanates, and oxiranes: An atom-economic route to morpholine derivatives

In situ generated copper acetylides react with isocyanates and oxiranes to form a decent range of morpholine derivatives. The reactions proceeded with acceptable yields and excellent regioselectivity. The presence of oxygen and moisture completely inhibited the reaction. The scope of the reaction is wide and the reactions involve consecutive C–C, C–N, and C–O bond formations.     

A simple radical addition-elimination route to geometrically pure (E)-alkene and chromanone derivatives via beta-nitrostyrene

Various geometrically pure (E)-beta-alkyl-styrenes have been synthesized by the radical NO(2) substitution of alkyl moieties generated via hydrogen abstraction followed by decarbonylation from aliphatic aldehydes. These reactions, which involve a high chemical selectivity and regioselectivity constitute a new route to (E)-beta-alkylstyrenes. Both aliphatic and aromatic aldehydes can be used in this novel reaction. When 2-allyloxybenzaldehyde was used, the benzoyl radical added directly to the double bond without decarbonylation to give the 3-cinnamylchroman-4-one. This unique difference between aliphatic and aromatic aldehydes represents a simple route for the synthesis of biologically important chromanones.     

Gamma-radiation initiated addition of allylbenzene to the morpholine

Radiation induced addition of allylbenzene to morpholine in liquid state was investigated by UV-, IR-spectroscopy and GS/mass spectrometry. Conversion of monomer depends on its initial concentration in the solution and this value is maximum for 0.05M solution. Radiation chemical yield of the product,G _prod , increases with concentration of allylbenzene and for 0.15M solution it is equal approximately 9.7 molec/100 eV. This value points on chain character of the process. Final product was identified by electron impact mass-spectrometry. The scheme of the EI induced fragmentation of product is proposed.     

Disproportionation of alkyldichlorosilanes in presence of N-cyano derivatives of piperdine and morpholine

Conclusions The N-cyano derivatives of piperidine and morpholine were proposed as being efficient catalysts for the disproportionation of alkyldichlorosilanes. Their use makes it possible to convert alkyldichlorosilanes to alkylchlorosilanes in up to 90% yield.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, p. 1181, May, 1978.     

Enantioselective addition of diethylzinc to benzaldehyde in the presence of ephedrine derivatives

Diethylzinc reacts with benzaldehyde derivatives to yield 1-aryl-1-propanols. In the presence of ephedrine and its derivatives an optical yield of up to 80% is obtained for reaction at room temperature without special precautions.     

A simple route to derivatives of benzo[j]fluoranthene

3,6,8,11-Tetramethoxybenzo[j]fluoranthene can be made from 1,6-dimethoxynaphthalene in a one-pot ferric chloride oxidation/methanol reduction procedure. The reaction is tolerant of the presence of substituents in the 7-position of the naphthalene nucleus and provides a quick and easy route to these particular benzo[j]fluoranthenes. The reactions presumably proceed through initial formation of a bond between the 4-positions of two naphthalene molecules followed by closure of the five-membered ring. Indeed in one case some 4,4′-binaphthyl was isolated from the reaction mixture and it was generally found that better yields of the benzo[j]fluoranthrenes were obtained starting from the 4,4′-binaphthyl rather than by using the naphthalene as the starting material. In an analogous manner to the ring-closure of the 4,4′-binaphthyls, starting from a hexakisalkoxyphenylnaphthalene, a hexakisalkoxyfluoranthene could be obtained.     

A simple route for the synthesis of novel norcantharimide derivatives via acidolysis with hydrochloric acid(gas)

In this work, seven new norcantharimide derivatives were synthesized by an acidolysis method. The compounds were prepared by acidolyzing trans-1,4-diacetate and trans-1,2-chloroacetate structures, which were obtained by stereospecific cleavage of the internal etheric bond of the tricyclic imides. The HCl_(gas) was produced from the reaction of H₂SO₄ with NaCl. The resulting gas was bubbled into the reaction mixture. Trans-1,4-diacetate and trans-1,2-chloroacetate were thus acidolyzed, and the corresponding diol and halohydrin products were obtained respectively in moderate overall yields from low-cost starting materials, using simple and easily scalable chemistry. The products were characterized by means of spectroscopic techniques. The synthesized compounds have high potential as anticancer agents and can be valuable for studies in this area.     

Polyphosphate chains by addition of oxiranes to phosphoric acid

Addition of diepoxides to the acids of phosphorus provides a new, attractive route to polyphosphates. In order to understand better the mechanism of this reaction and the structure of the products, the model reactions, namely additions of simple oxiranes to the acids of phosphorus, have been studied. It was shown that this reaction is catalysed by the P-OH groups of the acids. Activation of the oxirane molecule occurs predominantly by formation of the hydrogen bonded species while ionized form of acid plays only a minor role at the studied conditions (1,4-dioxane solution, 25°C). Reactivity of subsequent P-OH groups in phosphoric acid increases with increasing degree of substitution by -OCH₂CH₂OH groups. The ratio of the rate constants of formation of mono-, di-, and triesters of phosphoric acid is equal to 1/2/4. This has been attributed to the formation of internal hydrogen bonds, involving substituents and the P-OH groups. The observed order of the rate constants shows that reaction can not be stopped at the diester stage (linear units) and triester species (branched units) are formed fast. However, due to the large difference in the rate of hydrolysis, especially pronounced at basic conditions, triesters of phosphoric acid can easily be converted into the corresponding diesters by simple hydrolysis. Thus, the addition of diepoxides to phosphoric acid, followed by hydrolysis, leads to essentially linear polyphosphate chains.     

A new route to sulfonamides via intermolecular radical addition to pentafluorophenyl vinylsulfonate and subsequent aminolysis

[reaction: see text] Various radical species generated from either the corresponding iodo- or bromo- compounds and tri-n-butyltin hydride were added in an intermolecular fashion to the activated acceptor pentafluorophenyl vinylsulfonate. The products of each reaction were then subjected to aminolysis with a variety of different amines.     

A simple catalytic route to naproxen

We report herein the asymmetric synthesis of naproxen involving catalytic enantioselective methylation for the first time. The reaction is conducted in a solid–liquid biphasic system using chiral quaternary ammonium salts.     

A simple route to β-aminomethylketones

A simple procedure leading to β-aminomethylketones has been developed. The procedure involves base-catalyzed Michael-type addition of sodium t-butyl acetoacetate to N-Boc imines generated in situ followed by hydrolysis and decarboxylation of the adducts.     

A simple route to cyclopentane annulation

We have developed a simple method for cyclopentane annulation using inexpensive reagents which is useful for the synthesis of polyquinane systems.     

A new,simple, one-pot route for the synthesis of azocine derivatives

A novel, simple, one-pot procedure for the synthesis of new 7H-naphtho[1,8-ef]pyrimido[4,5-b]azocine-7,10,12,13(8H,9H,11H)-tetraones by the addition reaction of acenaphthoquinone and 6-aminouracil derivatives followed by oxidative cleavage of the corresponding intermediate product in the presence of lead(IV) acetate is reported. Clean reactions, excellent yields, and mild conditions are the main features of this method. The structural assignments are supported by ¹H NMR, ¹³C NMR, and X-ray crystallography data.     

A stereo-divergent route to aminocyclopentitol derivatives

A stereo-divergent synthetic strategy based on diastereoselective vinylation of an α-amino aldehyde, ring-closing metathesis reaction and diastereoselective dihydroxylation reaction as key steps has been developed for the synthesis of three aminocyclopentitol derivatives of chemical and biological relevance.     

A new synthetic route for the preparation of β-acyloxy mercaptans via the addition of thioacids to epoxides

A new synthetic route for the preparation of S-benzylated β-acyloxy mercaptans starting from the one-pot reaction of thioacids and epoxides using a silica gel/Et₃N combined catalyst is described. The thiol functionality in the crude product is then protected via benzylation and the corresponding thioethers are isolated after chromatography.     

A new route to the synthesis of isoxazoline derivatives from dihydropyran via cycloaddition reaction in ionic liquid

A new approach to the synthesis and 1,3-dipolar cycloadditions of nitrones has been described from 2,3-dihydro-4H-pyran and various hydroxylamines, with electron-deficient alkynes for the synthesis of isoxazoline derivatives. Significant rate acceleration and improved yields of exclusively exo isoxazolines in 1-butyl-3-methylimidazolium based ionic liquids have been observed. Novel isoxazolines may be used as a precursor for the synthesis of variety of peptides.     

Conjugate addition of hydroxylamino derivatives to alkylidene malonates in the presence of chiral Lewis acids

The conjugate addition of O-benzylhydroxylamine and N,O-bis(trimethylsilyl)hydroxylamine to alkylidene and arylidene malonates in the presence of Lewis acids affords the corresponding β-hydroxylamino derivatives in good yields. The use of Cu(OTf)₂ in the presence of chiral bisoxazoline ligands opens the possibility of performing this reaction in a catalytic and enantioselective way.     

A simple route to nanocrystalline silicon carbide

Nanocrystalline silicon carbide has been prepared via reacting magnesium silicide (Mg₂Si) with carbon tetrachloride (CCl₄) in an autoclave at 450-600°C. X-ray diffraction patterns of the products can be indexed as the cubic cell of SiC with the lattice constant, a=4.352 Å, in good agreement with a=4.349 Å (JCPDS card No. 75-0254). The transmission electron microscopy images show that the sample mainly consists of nanoparticles with an average size from 30 to 80 nm co-existing with a small fraction of nanorods and nanowires. Typically the nanorods range from 20 to 40 nm in diameter and the nanowires have diameters of 20 nm and lengths up to 10 μm. The Raman spectrum shows a characteristic sharp peak at 790 cm⁻¹. X-ray photoelectron spectra (XPS) gives an atomic ratio of Si to C as 1.08:1.00 from the quantification of the peak intensities. Photoluminescence spectrum reveals that the SiC sample emits ultraviolet light of 328 nm. A possible mechanism and the influence of temperature on the formation of crystalline SiC are proposed.     

A simple route to chiral phosphinous acid-boranes

We report a simple one-pot synthesis of enantiomerically enriched alkyl- and arylphenylphosphinous acid-borane starting from readily available (R(P))-(-)-menthylhydrogenophenylphosphinate and organolithium reagents.