The catalytic synthesis of homologs of pyrrolidine from furan amines

Summary 1-Furyl-2-alkyl-3-aminopropanes are converted by hydrogenation on platinum in a flowing system at 200–220° to 2-n-propyl-4-alkyl-pyrrofidines with yields of 85–90%.     

Synthesis of 2,5-dialkylpyrrolidines by conjugated catalytic hydrogenolysis of furan amines

Conclusions In hydrogenation in the vapor phase on a skeletal nickel-aluminum catalyst at 210–220°, 1-furyl-3-aminoalkanes undergo conjugated hydrogenolysis of the furan series at the 1,5-, 1,5- and 4,5-, as well as 1,5- and 3,4-bonds, forming 2-methyl-, 2-ethyl-, and 2-n-propyl-5-alkylpyrrolidines in yields of 38, 19, and 43%, respectively.Translated from Izvestiya Akademii Nauk SSSR, Setiya Khimicheskaya, No. 6, pp. 1120–1123, June, 1964     

Investigation of the mechanism of catalytic recyclization of furan to thiophene

Investigation of the formation of thiophene from furan and hydrogen sulfide at various catalysts showed that the activity of the catalysts increases with increase in the strength and concentration of Lewis acid centers. It was found by IR spectroscopy that if the degree of coverage of the aluminum oxide surface with hydrogen sulfide is higher than monolayer its dissociative chemisorption does not occur. Mechanism was postulated wich assume that the reaction takes place through stage with the formation of a surface intermediate, including coordination of the α-carbon atoms of the furan ring with the Lewis acid center and with the sulfur atom of molecular hydrogen sulfide.     

Saturated nitrogen heterocycles. 13. Mechanism of formation of hydroxyalkylpyrrolidines by catalytic hydrogenation of furan amines

The formation of hydroxyalkylpyrrolidines from furan amines has been modeled using deuterium exchange. The stages of the reaction were established by comparing the ¹³C NMR spectra of the nondeuterated and deuterated pyrrolidinylalkanols, and the similarly formed tetrahydrofuran amines.For Communication 12, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 177–182, February, 1990.     

A sulfone-based strategy for the preparation of 2,4-disubstituted furan derivatives

2,4-Disubstituted furans are prepared by treating 2,3-dibromo-1-phenylsulfonyl-1-propene (DBP, 2) with 1,3-diketones under basic conditions. The furan-forming step involves a deacetylation, and the selectivity of this process depends upon the steric demand of the R group. The substituent in position 4 is elaborated by reaction of sulfonyl carbanions with alkyl halides, acyl halides, and aldehydes. Oxidative or reductive desulfonylation produces the 2,4-disubstituted furans in 60-92% yield. This strategy has been used to prepare rabdoketone A (12) and the naturally occurring nematotoxic furoic acid 13.     

催化转移氢化还原腈类化合物成胺

本文报道了在碱性条件下, 用水合肼处理氯化镍(NiCl2.6H2O)得到活性镍催化剂, 不经分离直接用于催化转移氢化还原腈类化合物成胺。方法温和简便, 收率中等(35～82%)。α, β-不饱和腈还原时收率较低(12～17%)。     

Associated hydrogenolysis in the synthesis of 2,5-dialkylpyrroles

Summary The associated hydrogenolysis of the furan ring in 1-furyl-3-aminoalkanes on skeletal Ni-Al catalyst at 300° results in the formation of pyrrole homologs, containing either the methyl, ethyl or the n-propyl group in the-position. The yields are respectively: 30, 25, and 45%.     

Application of a thermochemical selectivity criterion to the catalytic oxidation of butadiene to furan and maleic anhydride

It is shown that the selectivity of furan formation from butadiene is not limited by the C−H bond strengths of the molecules involved and that ring fission energies are not suitable data for the criterion applied.     

The reactivity of furan compounds in vapor-phase catalytic oxidation

The reactivity of furan compounds in vapor-phase oxidation with air over a vanadium-molybdenum-phosphorus catalyst on low-porosity corondum has been studied under nongradient conditions. It has been established that the rate of the over-all conversion of the furan compounds studied and the rate of accumulation of maleic anhydride in the cycle decreases in the sequence: furan > furfural > tetrahydrofuran > furfuryl alcohol > 2-methylfuran > 5-methylfurfural, and the selectivity relative to the formation of maleic anhydride decreases in the following sequence: furan > tetrahydrofuran > furfural > furfuryl alcohol > 2-methylfuran > 5-methylfurfural. Some considerations relating to the mechanism of the reaction studied has been put forward.     

Mutual catalytic conversions of unsubstituted furan and pyran systems

The conversions of furan, di- and tetrahydrofuran, and di- and tetrahydropyran on a molybdenum catalyst in a hydrogen atmosphere have been investigated. The studied cyclic systems readily undergo mutual conversions at 125–215°C and also undergo a hydrogenation-dehydrogenation reaction. Expansion of the unsubstituted furan rings to pyran without the introduction into the reaction medium of components capable of generating methyl radicals are described by us for the first time. Latvian Institute of Organic Synthesis, Riga LV-1006 e-mail:leite@osi.lanet.lv. Translated from Khimiya Geterosiklicheskikh Soedinenii, No. 12, pp. 1658–1660, December, 1998.     

Incomplete catalytic oxidation of furan compounds (review)

The catalytic oxidation of furan compounds in the vapor and liquid phases is reviewed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 881–894, July, 1977.