Carbon-carbon cyanoethylation of anisole and its derivatives: Synthesis of a potential intermediate for ring-C aromatic steroid

Cyanoethylations of o-cresyl methyl ether, anisole, α-naphthyl methyl ether, resorcinol dimethyl ether, and 1,7-dimethoxynaphthalene provided the desired products in reasonably good yields: synthetic applications are indicated.     

Alkylation of Imidazole-4(5)-carboxylic Acid Derivatives with Methyl Bromoacetate

The alkylation of imidazole-4(5)-carboxylic acid anilide and methyl ester with bromoacetic acid and its methyl ester in neutral and alkaline media yields, along with monoalkylation products, 1,3-bis(2-methoxycarbonylmethyl)-4-R-imidazolium bromide. The monoalkylation of methyl imidazole-4(5)-carboxylate yields a 1:1 mixture of the 1,4- and 1,5-isomers, and the monoalkylation of imidazole-4(5)-carboxylic anilide selectively provides the 1,4-isomer.     

Phosphorylation of D-glucose derivatives with inorganic monoimido-cyclo-triphosphate

Phosphorylation of several D-glucose derivatives has been achieved using inorganic monoimido-cyclo-triphosphate (MCTP, Na(3)P(3)O(8)NH) in aqueous solution. In the phosphorylation of D-glucose, D-glucuronic acid, 2-deoxy-D-glucose and D-galactose, 1-O-diphosphoramidophosphono-beta-D-glucose, 1-O-diphosphoramidophosphono-beta-D-glucuronic acid, 1-O-diphosphoramidophosphono-2-deoxy-beta-D-glucose, and 1-O-diphosphoramidophosphono-beta-D-galactose were stereoselectively synthesized with yields of 54, 32, 37 and 46%, respectively. In the case of methyl alpha-D-glucoside, the phosphorylated products were methyl 3-O-diphosphoramidophosphono-alpha-D-glucoside and methyl 4-O-diphosphoramidophosphono-alpha-D-glucoside, and in the case of methyl beta-D-glucoside the products were methyl 2-O-diphosphoramidophosphono-beta-D-glucoside, methyl 3-O-diphosphoramidophosphono-beta-D-glucoside, and methyl 4-O-diphosphoramidophosphono-beta-D-glucoside. For D-mannose and D-allose, several phosphorylated products were obtained and the main products were 1-O-diphosphoramidophosphono-beta-D-aldoses.     

Unusual head-to-tail coupling of alkyl benzoates by electroreduction.

The electroreduction of alkyl benzoates in an alcoholic solvent gave unusual head-to-tail coupled products. Usual head-to-head coupled products derived from acyloin condensation could not be detected. The best result (73% yield) was obtained from methyl benzoate using an undivided cell with an Sn cathode in i-PrOH containing tetraalkylammonium salt as a supporting electrolyte. Using an undivided cell, the products cross-coupled with a solvent molecule were obtained as byproducts. The substitution at the para position of methyl benzoate considerably decreased the yields of the head-to-tail coupled products and increased those of the cross-coupled products. The possible mechanism of the head-to-tail coupling is the attack of anion radical, generated from methyl benzoate by one-electron transfer, to another methyl benzoate. The cross-coupled products were formed by the reaction with carbonyl compound anodically produced from a solvent molecule. The cross-coupling between methyl benzoate and aromatic aldehydes was also effected by the mixed electroreduction under the same conditions.     

Synthesis of novel 3,5-disubstituted-dihydroisoxazoles from methyl undec-10-enoate and isoxazoles,triazole and tetrazolo-triazole from methyl undec-10-ynoate

The efficient cycloaddition reactions were carried out to afford the novel 3,5-disubstituted-dihydroisoxazoles from methyl undec-10-enoate and isoxazoles, triazole and tetrazolo-triazole from methyl undec-10-ynoate. The reactions occurred under relatively mild conditions and afforded the desired products in good yields.     

Electron–proton and electron–methyl exchanges in pyrolysis of polyacetylene and polymethylacetylene

Pyrolysis of polyacetylene is marked by high yields of proton-enriched products methane, ethane, ethylene, propane, polypylene, butadiene, cyclopentadiene, 1,3-pentadiene, and toluene in total amounts exceeding benzene. The activation energies for their formation are low. Polyacetylene doped with AsF₅ and iodine produced these products in even higher yields of two to 17 times of undoped polymers. The dominant mechanism is thought to be random-chain scission followed by electron–proton exchange reactions. Polymethylacetylene is thermally less stable than polyacetylene. Pyrolysis gave mesitylene as the expected main product. However, as in the case of polyacetylene, large amounts of proton-enriched products were formed with moderate activation energies. (The yields of methane, propylene, and propane are nearly the same in the pyrolysis of polymethylacetylene as compared to that of polyacetylene at 923°K referenced to mesitylene and benzene, respectively.) By analogy, mechanisms involving both electron-proton and electron–methyl exchange reactions were proposed to account for the formation of all the pyrolyzates of polymethylacetylene. These reactions, not observed in the pyrolysis of polypropylene and polyisoprene, are attributable to the conjugated backbone permitting facile migrations of electrons, protons, and methyl groups.     

Preparation and degradation of copolymers of methyl methacrylate with alkali metal methacrylates—III. Quantitative studies of products of degradation to 500°

Degradations have been carried out under programmed heating conditions to 500 in racuo for the three copolymer systems based upon methyl methacrylate with lithium, sodium and potassium methacrylate respectively. Products have been analyzed quantitatively and the mode of variation in the yields of the principal degradation products with copolymer composition has been established. As the salt content increases, methyl methacrylate monomer production declines and the amount of solid residue increases, in both cases non-linearly. Methanol and carbon dioxide productions however, pass through maxima in the intermediate composition range. The relationships between these product yields and copolymer structure and degradation mechanism are discussed.     

rac-BINAP-PdCl2 catalyzed Heck reactions of 3-formylquinolin-2-yl chlorides with methyl acrylate: synthesis of methyl 3-(3-formylquinolin-2-yl) acrylates

rac-BINAP-PdCl₂ catalytic system catalyzed Heck reaction of 3-formylquinolin-2-yl chlorides with methyl acrylate in DMA is described to the synthesis of methyl 3-(3-formyl-quinolin-2-yl)-acrylates, in good to excellent yields. The reaction could be also extended with other activated alkenes to afford Heck products. Fused-benzene ring in heterocyclic and carbocyclic moieties was found to enhance the yields.     

Conjugate addition of chiral lithium methyl[o(cyclohexyldimethylaminomethyl)phenyl]cuprate to methyl 3-phenyl-2-propenoate and 4-phenyl-3-buten-2-o

Chiral lithium methyl[o-(cyclohexyldimethylaminomethyl)phenyl]cuprate reacts with methyl 3-phenyl-2-propenoate and 4-phenyl-3-buten-2-one to give the conjugate addition products, viz. methyl 3-phenylbutanoate and 4-phenylpentan-2-one respectively. The reaction rates and chemical yields (30–60%) are lower than in corresponding reactions with lithium dimethylcuprate and lithium methyl[2-(1-dimethylaminoethyl)phenyl]cuprate respectively. Lithium halides in the reaction favour the formation of one enantiomer. The highest asymmetric induction obtained is 4.4%.     

Radiation Degradation of Copolymers. III. Poly(styrene-co-methyl Acrylate)

The distribution of volatile products from γ-irradiation of copolymers of styrene and methyl acrylate is independent of the composition of the copolymer and the same as that obtained from poly(methyl acrylate). The yields are less than proportional to the methyl acrylate content, Indicating a protective effect from the styrene units as observed previously in copolymers of styrene with methyl methacrylate. The flexural strengths of the copolymers, measured at 1°C, decrease with radiation dose for high styrene content, but increase for high methyl acrylate content. Samples irradiated in air have appreciably lower strengths than those irradiated in vacuum. Gel measurements show intermediate behavior for the copolymers between the homopolymers.     

Rapid and sensitive determination of the conversion of UV-cured acrylic ester resins by pyrolysis-gas chromatography in the presence of an organic alkali.

The double-bond conversion of UV-cured resins prepared from pentaerythritol triacrylate (PETA) was determined by pyrolysis-gas chromatography in the presence of an organic alkali, tetramethylammonium hydroxide (TMAH). The pyrogram of the uncured prepolymer compound, consisting of PETA and a photoinitiator, 2,2-dimethoxy-2-phenylacetophenone, contained specific products reflecting the original acrylate structure, such as methyl acrylate (MA) and methyl ethers of pentaerithritol. Meanwhile, in pyrograms of the UV-cured PETA, the yields of MA considerably decreased. The double-bond conversions of the cured resins, irradiated with various UV dosages, were calculated based on the relative yields of MA among specific products in the pyrograms. The conversions determined by this approach were analyzed by comparing them with those estimated by Fourier-transform infrared spectroscopy.     

Two-step preparation for catalyst-free biodiesel fuel production

Biodiesel fuel was prepared by a two-step reaction: hydrolysis and methyl esterification. Hydrolysis was carried out at a subcritical state of water to obtain fatty acids from triglycerides of rapeseed oil, while the methyl esterification of the hydrolyzed products of triglycerides was treated near the supercritical methanol condition to achieve fatty acid methyl esters. Consequently, the two-step preparation was found to convert rapessed oil to fatty acid methyl esters in considerably shorter reaction time and milder reaction condition than the direct supercritical methanol treatment. The optimum reaction condition in this two-step preparation was 270°C and 20 min for hydrolysis and methyl esterification, respectively. Variables affecting the yields in hydrolysis and methyl esterification are discussed.     

The use of chiral BINAM NHC-Rh(III) complexes in enantioselective hydrosilylation of 3-oxo-3-arylpropionic acid methyl or ethyl esters

Axially chiral BINAM N-heterocyclic carbene (NHC)-Rh(III) complexes were applied in the enantioselective hydrosilylation of 3-oxo-3-arylpropionic acid methyl or ethyl esters. The reduction products 3-hydroxy-3-arylpropionic acid methyl or ethyl esters could be obtained in good yields with good to excellent enantioselectivities under mild conditions.     

Synthesis of l-arabinopyranose containing hederagenin saponins

The synthesis of eight hederagenin saponins, five of which are natural products, and their methyl esters is described as part of an ongoing study of the biological activity of triterpenoid saponins. Six disaccharides consisting of an l-arabinopyranose glycosylated in positions 2, 3, or 4 with a β-d-xylopyranose or a β-d-glucopyranose residue, respectively, were synthesized in good to excellent yields. The saponins were then prepared in good yields through glycosylation with a suitably protected hederagenin derivative followed by total deprotection and treatment with diazomethane.     

Cobalt-catalyzed intermolecular [2 + 2 + 2] cycloaddition for the synthesis of 1,3-cyclohexadienes

A cobalt(I)-catalyzed [2 + 2 + 2] cycloaddition reaction between an internal acceptor-substituted alkyne and a terminal alkene leads to the formation of regiochemically enriched polysubstituted 1,3-cyclohexadiene derivatives in acceptable yields when methyl butynoate is used, whereas regiochemically pure products are formed in good yields form phenyl propyonate. The concurrent cyclotrimerization reaction of the alkyne to the corresponding benzene derivative is dependent on the sterical bulk of the alkyne and is considerably reduced with the sterically more hindered alkyne.     

Cyano-Carbonates (II) -Eficient Iatent Acyl Carbanious in 1,4-Additions

Alkylations of cyano-carbonate anions with ethyl acrylate or methyl vinyl ketone followed by hydrolysis yield 1,4-addition products in excelleat yields.     

Addition of diazomethane and sulfur ylides to the oxo-group in derivatives of ketoses and aldoses : I. Reactions of 2,3-O-isopropylidene-D-glyceraldehyde

The reaction between 2,3-O-isopropylidene-D-glyceraldehyde and diazomethane, dimethylsulfonium methylide and dimethyloxosulfonium methylide has been studied. The sulfur ylides yield two epimeric epoxides, 1,2-anhydro-3,4-O-isopropylidene-D-erythritol and 1,2-anhydro-3,4-O-isopropylidene-D-threitol, with a slight preference for the erythro isomer.The reaction with diazomethane yields in addition to the epoxides a methyl ketone, 1-deoxy-3,4-O-isopropylidene-D-glycero-tetrulose. The relative yields of the three products have been discussed on the basis of mechanisms previously proposed for the reactions. The yield of methyl ketone was lowest when the reaction was carried out in pure diethyl ether solution. This solvent also gives the greatest preference for the erythro isomer of the two epoxides. Constitution and stereochemistry for the three products have been shown by synthesis.     

Enantioselective route to ferrugine and its methyl analogue via aldol deoxygenation

A simple enantioselective approach to ferrugine (2α-benzoyltropane) and its methyl analogue (2-acetyltropane) is reported. The four-step sequence uses an enantioselective aldol reaction of tropinone with benzaldehyde or acetaldehyde, combined with an aldol deoxygenation via tosylhydrazone reduction and oxidation of the side-chain hydroxy group. The final products, ferrugine and its methyl analogue, are prepared in 35% and 23% overall yields, respectively. Both enantiomers of the products (ee 90-99%) are accessible via the same route using either enantiomer of N,N-bis(1-phenylethyl)amine hydrochloride as the chiral reagent.     

A new method of olefin synthesis. Coupling of lithium dialkylcuprates with enol triflates

Enol trifluoromethansulfonates react with lithium dialkylcuprates to give the coupling products in high yields. The reaction is stereoselective and is successful with a wide variety of organocuprates, including methyl, butyl, phenyl, vinyl, and cyclopropyl reagents.     

A product study of the gas-phase reaction of Isoprene with the OH radical in the presence of NOx

The gas-phase reaction of isoprene with the OH radical, in the resence of NO_x, was investigated at 298 ± 2 K and atmospheric pressure of air by long path length FT-IR spectroscopy. The primary products identified and their formation yields were: methacrolein, 0.21 ± 0.05; methyl vinyl ketone, 0.29 ± 0.07; and HCHO, with the observed yield being consistent with the sum of the methacrolein and methyl vinyl ketone yields. Combined with the previously reported yield of 0.044 ± 0.006 for 3-methylfuran, these products accounted for 55 ± 9% of the isoprene which reacted. Under conditions where the dark reaction of isoprene with NO₂is not significant, the balance of the isoprene consumed could possibly be accounted for by the “organic nitrates” and “other carbonyl compounds” formed in estimated overall yields of ca. 12% and ca. 25%, respectively.