Decarbonylation of furfural over oxide catalysts

Gas chromatography has been used to investigate the products accompanying tetrahydrofuran prepared by hydrogenation of furan, without isolating the latter pure from the gas mixture obtained by decarbonylating furfural over oxide catalysts. A number of unknown impurities accompanying tetrahydrofuran and furan, are identified. It is found that tetrahydrofuran contains isopropanol, along with furan,-methylfuran, and-methyltetrahydrofuran. Furan itself contains-methylfuran, and a number of unknown impurities, among them acetone. Ethane is found among the gaseous products of decarbonylation. Thus over Zn and Mn oxide catalysts there is joint hydrogenolysis of the furan ring, and ring opening at positions 1–5 and 3–4.     

Catalytic hydrogenolysis of alkylfurans

The vapor-phase conversion of -methylfuran and -methyltetrahydrofuran on a sodium and potassium-activated palladium catalyst in a stream of hydrogen at atmospheric pressure at 200–450°C was investigated. Hydrogenolysis of -methylfuran and isomerization of -methyltetrahydrofuran to give 2-pentanone in both cases occur at 300° with identical selectivities. It is assumed that aliphatic ketones are formed from the alkylfurans on this catalyst via a parallel-consecutive scheme through direct hydrogenolysis of the alkylfurans and isomerization of their tetrahydro derivatives, which are formed as intermediates.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 43–45, January, 1976.     

Polyfuryl(aryl)alkanes and their derivatives. 7. New recyclization and cyclization reactions in the 2-hydroxyaryldifurylmethane series

Reaction of 2-hydroxybenzaldehydes with -methylfuran (sylvan) under acid-catalysis conditions was investigated. It is shown that the reaction does not stop at the step involving formation of 2-hydroxyarylfuryl-methanes but proceeds further with opening of one of furan rings and recyclization to 3-furylbenzo-furan derivatives. The latter in turn undergo transformations that lead to new heterocyclic systems — 5,6-dihydro-2,4-dimethyl-4-(5-methyl-2-furyl)-4H-benzo[b]furo[2,3-h]cyclopenta[b]furans. Data from the IR, PMR, and mass spectra, alternative synthesis, and x-ray diffraction analysis were used to confirm structures of the synthesized compounds.For Communication 6 see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 616–626, May, 1993.     

Reactions of furan derivatives with aliphatic carbonyl compounds in acid medium

Sixteen new derivatives of the furan and of the 1,1-difurylmethane series were synthesized by the reactions of furan, 2-methylfuran, 2-(3-acetoxypropyl)furan, 2-(3-butyl)furan, 1-cyclopropyl-2-furylcyclopropane, and 1,1-difurylethane with saturated and , -unsaturated aliphatic carbonyl compounds in acid medium.     

Reaction of furan compounds with hydrogen sulfide and aspects of its application

The conversion of -methylfuran, di- and polyalkylfurans, and ethers, esters, ketones, and other derivatives of the furan series to the corresponding substituted thiophenes was realized under acid-catalysis conditions.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1453–1456, November, 1986.     

Structural modification of silica-containing α-zirconium phosphate

Silica-containing -zirconium phosphate (-ZrSiP) was prepared by the precipitation method. X-ray diffractometry was used to characterize -ZrSiP and to compare it with other -zirconium phosphates (ZrP). A monoclinic cell with parameters of a=0.9038 nm, b=0.529 nm, c=1.4183 nm and =91.76° was identified for -ZrSiP, i.e. silica modifies the original -ZrP structure. The specific surface area of -ZrSiP was found to be two orders of magnitude higher then that of -ZrP.     

Synthesis of bacterial antigenic polysaccharides and their fragments 6. Improved synthesis of β-D-mannopyranosyl-(1→4)-α-1-rhamnopyranosyl-(1→3)-D-galactose- the repeating unit of the specific polysaccharide of Salmonella Newington

Conclusions We have synthesized the trisaccharide-D-mannopyranosyl-(1 4)--L-rhamnopyranosyl-(1 3)-D-galactose using 1,2-O-isopropylidene-4,6-O-ethylidene--D-galactopyranose to form the 1 3 rhamnosylgalactose linkage.Part 5 [1].Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2578–2581, November, 1977.     

Furan compounds

By reductive amination, starting from furfural, 5-methylfurfural, -(2-furyl)acrolein, and monoethanolamine, we have obtained N-furfurylaminoethanol, N-(5-methyl-2-furfuryl)aminoethanol, and N-[1-(-furyl)-3-propyl]aminoethanol. By reductive amination combined with the subsequent hydrogenation of the furan ring we have obtained N-tetrahydrofurfurylaminoethanol and N-(5-methyltetrahydro-2-furfuryl)aminoethanol.For part XXXIII, see [1].     

Saturated nitrogen heterocyclic compounds

Results are given of research on the synthesis of-pyrrolidylalkan-3-ols by hydrogenating primary and secondary furan amines under pressure over Raney nickel in aqueous acid solution. Some views about the mechanism of the reaction are put forward. It is shown that the relative yields of the-pyrrolidylalkan-3-ols and corresponding tetrahydrofuran amines depend both on structural peculiarities of the starting furan amine, and on the hydrogenation conditions.     

2-Substituted 3-Methylfurans

In the acylation of 3-methylfuran, acetyl and formyl groups enter predominantly into position 2 with the formation of 2-acetyl-3-methylfuran and 2-formyl-3-methylfuran; the latter readily reacts with methyl ketones and methoxycarbonylmethylenetriphenylphosphoranes with the formation of the corresponding ,-unsaturated compounds.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1011–1013, August, 1973.     

Kinetics of the Hydrogenation of α-Pinene to cis- and trans-Pinanes on Pd/C

The liquid-phase hydrogenation of -pinene on a Pd/C catalyst at 0–100° and hydrogen pressures of 1–11 atm was studied. It was found that the order of reaction with respect to pinene increased with hydrogen pressure and did not depend on temperature, whereas the selectivity of cis-pinane formation decreased with temperature and increased with hydrogen pressure. A mechanism was proposed for the hydrogenation of -pinene. According to this mechanism, the selectivity of cis-pinane formation depends on the following two factors: (a) a temperature-dependent equilibrium between adsorbed -pinene species, which are cis- and trans-pinane precursors, and (b) competition between the hydrogenation and -H-elimination of surface -pinanyl complexes. The ratio between the rates of these reactions depends on the concentration of surface hydride species, and this concentration depends on the pressure of hydrogen.     

Refinement of the structures of triterpenes from the leaves ofBetula ermanii

From the unsaponifiable part of an ethereal extract of the leaves ofBetula ermanii two previously unknown triterpenes (II) and (I) have been isolated to which, previously, the structures of 20, 24-epoxydammarane-3,6,25-triol and its 6-acetate were erroneously ascribed. A further study of the¹H and¹³C spectra of compounds (II) and (I), and also the spectra of their derivatives — the diketone (III) and the epimer of the triterpene (II) at C¹¹ (IV) — has shown that the triterpene (II) has the structure of 20(S),24(R)-epoxydammarane-3,11,25-ttriol, and the triterpene (I) is its 11-acetate. Triterpenes (I) and (II) are the first examples of natural 11-hydroxylated C₃₀-triterpenes of the dammarane type.Pacific Ocean Institute of Bioorganic Chemistry of the Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 50–53, January–February, 1980.     

Transformations of 4,5-Substituted (4S,5S)-2,2-Dimethyl-1,3-dioxolanes

(4S,5S)-4,5-Bis(hydroxymethyl)-2,2-dimethyl-1,3-dioxolane treated with trifluoromethanesulfonyl chloride in pyridine undergoes tandem substitution of one hydroxy group by a triflate group, and the other by pyridinium moiety. In neutral solvents the (4S,5S)-4,5-bis(hydroxymethyl)-2,2-dimethyl-1,3-dioxolane dilithium salt reacts with trifluoromethanesulfonyl chloride affording both triflates and chlorides and also suffers a cleavage of the dioxolane ring followed by transformations of acyclic products. A triflate cationic complex rhodium cyclooctadiene (4S,5S)-2,3-dihydroxy-1,4-bis(dimethylamino)-2,3-O-isopropylidenebutane was prepared and used as catalyst for hydrogenation of -acetamidocinnamic and itaconic acids.     

Thermal reactions of dihydrofurans

Summary In contact with active birch charcoal at 470–480° in a stream of nitrogen 2-n-propyl-4,5-dihydrofuran isomerized to propylcyclopropylketone, whereas 2-n-butyl-2,5-dihydrofuran was dehydrogenated to -butylfuran under the same conditions.     

Catalytic hydrogenation of furfurylideneacetone

The stepwise character of the hydrogenation of furfurylideneacetone on a Raney nickel catalyst at 50° C and atmospheric pressure was investigated. It is shown that the intermediate-1-(-furyl)-3-butanone — is primarily hydrogenated to 1-(-tetrahydrofuryl)-3-butanone.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 291–284, March, 1972.     

Asymmetric catalytic synthesis of lysine by hydrogenation of α-nitrocaprolactam

Conclusions The enantioselective hydrogenation of-nitrocaprolactam (I) is effected on a chiral Pd complex, obtainedin situ in the presence of S--phenylethylamine, to give S--aminocaprolactam (II), hydrolysis of which gives S-lysine. The optical yield varies from 1 to 13% according to the solvent and concentration of chiral ligand. On a Pd complex with S-N-isopropyl--phenylethylamine, enantioselective hydrogenation of (I) gives an excess of the S-enantiomer of (II) (2%). On a Pd complex with S-phenylalaninol, hydrogenation of (I) leads to the R configuration of (II) with EE 7.2%.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1597–1600, July, 1987.     

Catalytic asymmetric synthesis of lysine α-phenylethylamide by diastereoselective hydrogenation

Conclusions The catalyzed asymmetric synthesis of R-lysine S--phenylethylamide has been carried out by the diastereoselective hydrogenation of 5-cyano-2-hydroxyiminovaleric acid S--phenylethylamide over a skeletal nickel catalyst in a solvent containing -phenylethylamine, at raised pressures. The excess of the RS-diastereoisomer was 6–12%.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 849–852, April, 1987.     

Schiff bases in syntheses of substituted naphthylamines,naphthyridines, azaphenanthrenes,and benzocarbazole

9-Methylnaphtho[2,1-b][1,6]naphthyrldine and 2,3-dimethyl-1-azaphenanthrene were obtained on a K-16 dehydrogenating catalyst from N-(1,2,5-trimethyl-4-piperidylidene)--naphthylamine, while N-cyclohexylidene--naphthylamine yielded N-phenyl--naphthylamine and benzo[a]carbazole.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1400–1403, October, 1972.     

Effect of phase composition of palladium-ruthenium membrane catalyst on selectivity of dehydrolinalool hydrogenation

Conclusions When the hydrogenation of dehydrolinalool to linalool is run on a Pd alloy containing 6 wt.% of Ru, which is lean in the -hydrogen phase, the selectivity is much greater than when the amount of the -hydrogen phase is greater. A high selectivity of the hydrogenation is achieved by reducing to a definite limit the amount of hydrogen in the membrane catalyst without using inhibitors of the side reactions, which can contaminate the hydrogenation products.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 926–928, April, 1984.     

Reaction of α-cyanomethylazaheterocycles with α-halo carboxylic acid chlorides and anhydrides

-Cyanomethylazaheterocycles (I) are acylated by -halo carboxylic acid chlorides and anhydrides at the methylene carbon atom to give hetaryl-containing halo ketones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1515–1517, November, 1977.