Synthesis and properties of furan derivatives. 4. Synthesis of 2,5-disubstituted 1,3,4-oxadiazoles containing furan fragments

The condensation of hydrochloride sats of iminoesters of furan acids with hydrazides of carboxylic acids gives 2,5-disubstituted 1,3,4-oxadiazoles containing furan fragments. Such compounds are also formed in the condensation of hydrazides of 5-R-furan-2-carboxylic acids with hydrocloride salts of carboxylic acid iminoesters. The reaction of furan acids with hydrazine dihydrochloride in polyphosphoric acid gave symmetrically disubstituted 1,3,4-oxadiazoles containing furan fragments.Communication 3, see ref. [1].I. M. Gubkin State Petroleum and Natural Gas Institute, 117917, Moscow. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 238–249, February, 1995. Original article submitted January 24, 1995.     

Synthesis of furan from allenic sulfide derivatives

In this paper, we report the synthesis of furan derivatives from allenic sulfides. By the reaction with NaH, β-Hydroxyl allenic sulfides were found to generate furan products in excellent yields with the removal of phenylthio group. β-Aldehyde allenic sulfides were found to give similar furan products with one more substituent when treated with additional nucleophilic reagents. β-ketone allenic sulfides can also cyclize to give furan derivatives with the promotion of P₂O₅.     

联二烯丁基硫醚衍生物合成呋喃的反应

本文报道以联二烯丁基硫醚为起始物的呋喃衍生物的合成方法.实验结果表明,β-联二烯丁基硫醚醇在氢化钠的作用下以很高的收率环化生成一个苯硫基离去的呋喃产物,β-联二烯丁基硫醚醛与外加亲核试剂作用后能得到多一个取代的类似呋喃产物,而β-联二烯丁基硫醚酮在P2O5的促进下也能环化生成呋喃衍生物.     

Researches on furan compounds

This paper gives the results obtained by liquid phase catalytic hydrogenation under pressure, over ruthenium catalysts, of furan aldehydes, ketones, and carboxylic acids. It is shown that the ruthenium catalysts are highly effective for hydrogenating the furan ring, ethylenic double bonds, and the carbonyl group, though they are not selective with respect to them. At room temperature the furan ring is mostly reduced to a tetrahydrofuran one. It is confirmed that compounds containing the 1, 6-dioxaspiro [4, 4]-nonane grouping are formed by hydrogenating furfurylidene aldehydes and ketones, and -furylalkanols.For Part XXX see [15].     

Synthesis of functional furan derivatives by oxidation of furans and formylfurans with hydrogen peroxide

The review analyzes the effects of the reaction conditions on the direction of the reactions between furans/formylfurans and hydrogen peroxide. The revealed dependences serve for the synthesis of the desired products and for development of new methods to access α-hydroxy hydroperoxides of furan aldehydes, 2-furanoic acid and its esters and amides, a series of furoic acids bearing the substituent at the furan ring, 2(5H)-furanone and its homologs and functional derivatives, as well as 2,5-dialkoxydihydrofurans. The developed procedures are more advantageous than the conventional methods.     

Synthesis of the southern furan segment of furanocembranoids

Abstract

A convergent synthesis of the southern furan segment of novel furanocembranoids from Croton oblongifolius has been accomplished involving silver-catalyzed cyclization of alkynyl diol as the key step towards 2, 5-disubstituted furan ring formation.     

Reactions of catalytic oxidation of furan and hydrofuran compounds. I. General principles of the oxidation of furan in the system hydrogen peroxide-vanadium(IV) compounds depending on the type of solvent and catalyst

The oxidation of furan by aqueous hydrogen peroxide catalyzed by vanadium(IV) compounds was studied in homogeneous aqueous alcohol medium and a heterogeneous system in the presence of tridecylmethylammonium chloride. The optimum conditions of the process were determined for both versions. It was shown that they are similar in direction, duration, and degree of conversion of furan. At the same time, the composition and total yield of the products, as well as their yields in the organic and aqueous phases, depend on the type of solvent and vanadium catalyst.Kuban State Technological University, Krasnodar 350072. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 633–638, May, 1996. Original article submitted January 29, 1996.     

2-Halogenoethyl and 2-halogenoethylthiol esters of furan series carboxylic acids

The corresponding 2-chloroethyl (2-chloroethylthiol) esters are synthesized by the action of ethylene chlorohydrin (chloroethylmercaptan) on the acid chlorides of 5-nitrofuran carboxylic acid and 3-(5-nitrofuryl-2)acrylic acid. The acid chlorides of benzoic, furan carboxylic, and 3-(furyl-2)-acryllc acids react with ethylene sulfide, to give 2-chloroethyl esters of those acids. Ethylene oxide does not react with the acid chlorides of benzoic acid and furan series carboxylic acids either at room temperature or on heating at 50° for 1 hour.     

Identification of fatty acid methyl esters as minor components of fish oil by multidimensional GC-MSD: New furan fatty acids

The separation and analysis of furan fatty acids and other minor component fatty acids present at very low concentrations in complex sample matrices, such as fish oil or lipids derived from liver and testes, require several pre-analytical separation steps if single column gas chromatography is to furnish sufficient resolution: after extraction and transesterification hydrogenation, urea complex precipitation and argentation TLC have been applied prior to GC analysis of furan fatty acids. By using multidimensional GC-MSD with cooled injection and flow-controlled column switching with intermediate cold trapping, it has been possible to identify directly the methyl esters of furan fatty acids without further pre-analytical separation. The most common of the furan fatty acids can be subdivided into two groups depending on whether they bear a propyl or pentyl side group in the 5-position of the furan ring. In addition to the eight furan fatty acids known to be present in fish oil, six new ones were identified, four with propyl substitution and two with pentyl substitution. Four have earlier been reported to be present in the hepatopancreas of crayfish and in fish tissue, whereas the propyl-substituted 16,19-epoxy-17,18-dimethyldocosa-16,18-dienoic acid and the pentyl-substituted furan fatty acid 6,9-epoxy-7-methyltetradeca-6,8-dienoic acid were hitherto unknown.     

Synthesis of macrocyclic ligands incorporating sulfur and furan subunits

Abstract

Polyammonium macrocycles containing sulfur and furan units in the macrocyclic ring have been synthesized and studied for ATPase activity. The synthetic methodology involved using tosyl protection for the amines and the formation of macrocyclic Lactams, followed by reduction using borane in THF. Deprotection of the tosylated forms of the macrocycle was accomplished using sodium in butanol for the furan macrocycles, and HBr in HOAc for the sulfur containing macrocycle. The macrocycles were found to be poor catalysts for ATP hydrolysis compared to other similar polyammonium macrocycles.     

Synthesis of furan dimer‐based polyamides with a high melting point

Polyamide composed of furan dimer, which is prepared from biomass‐derived organic molecule 2‐furfural, is synthesized. The reaction of 2,2′‐furan dimer 5,5′‐dicarbonyl chloride with several 1,ω‐diamines was carried out with a solution or interfacial polycondensation leading to the corresponding polyamide. Measurement of the melting point was performed resulting to exhibit a higher temperature compared with the related polyamide bearing a single furan ring composed of furan‐2,5‐dicarboxylic acid (FDCA). Thermal analyses (TG–DTA) also indicated higher temperatures of decomposition than those of FDCA‐derived polyamide. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 1516–1519     

Synthesis of seven-membered oxacycles. Part 2: The furan approach

We describe an efficient new approach for the synthesis of seven-membered oxacycles that is based on the oxidation of a furan ring with singlet oxygen followed by an intramolecular Michael addition.     

Synthesis and crystal structure of 5-tert-butyldimethylsilyl-2-(2,2,2-trifluoro-hydroxyiminoethyl)furan

The oximation of 5-tert-butylmethylsilyl-2-(trifluoroacetyl)furan with hydroxylamine leads to the exclusive formation of the E-isomer of 5-tert-butyldimethylsilyl-2-(2,2,2-trifluorohydroxyiminoethyl)- furan.     

Reaction of furan derivatives with acryloyl chloride

Summary 2-Methyl-, 2-(2'-carbomethoxyethyl-, 2-(3'-oxobutyl)-, and 2-(3',3'-dimethoxypropyl)furans add acryloyl chloride to yield furan acid chlorides or substituted furancarboxylic acids, which with alcohols form the corresponding esters.     

Furan derivatives-IX : A convenient new method of arylation of furan reaction of diazoaminobenzenes with furan and isopentyl nitrite

A convenient new method for the arylation of furan with derivatives of diazoaminobenzene and isoamyl nitrite is described. Using this method the substituted 2-(X-phenyl)furan derivatives, where X is H, 4-CH₃, 4-Cl, 4-Br, 3-Cl, 3,4-diCl, 4-NO₂, 4-COOCH₃, 4-COOH, 4-Cl-3-CF₃ and 2-(3-pyridyl)furan were prepared. The reaction of methyl 4-aminobenzoate with furan and isopentyl nitrite gave (besides 2-(4-carbmethoxyphenyl)furan) 4,4′-dicarbmethoxydiazoaminobenzene, the structure of which was proved by mass spectrometry and by synthesis. This diazoaminobenzene derivative was unstable in the reaction medium and with isopentyl nitrite and furan at 30° gave 2-(4-carbmethoxyphenyl)furan. The mechanism of the reaction is discussed.     

Research on vinyl esters of the furan series

The reaction of vinyl esters of furan-2-carboxylic, 5-bromofuran-2-carboxylic, and trans-β-(2-furyl)acrylic acids with aliphatic, aromatic, and heterocyclic amines was investigated. It was established that azoles add to the double bond of the vinyloxy group of the ester in conformity with the Markownikoff rule. α-(1-Azolyl)ethyl esters of the furan-2-carboxylic and β-(2-furyl)acrylic acids were synthesized. Acylation of the amines takes place during the reaction of vinyl esters of the furan series with diethylamine, aniline, p-vinyloxyaniline, morpholine, and piperidine.     

Synthesis of oxoacids and oxoesters of the furan series

Summary ß-(Furyl-2)propionic acid and its methyl and ethyl esters add in acid medium to ,ß-unsaturated aldehydes and ketones, forming oxoacids and oxoesters of the furan series.     

Synthesis of difunctional derivatives in the furan and tetrahydrofuran series

Summary A number of previously unknown difunctional derivatives in the furan and tetrahydrofuran series was obtained by acetalization and liquid-phase hydrogenation.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 389–391, February, 1965     

Novel condensed heterocyclic derivatives of benzofuran based on 2,5-dihydroxy-3,4,6,7tetrachloro-2, 3-dihydrobenzo[b]furan

We have synthesized novel condensed heterocyclic derivatives of benzofuran by reaction of 2,5-dihydroxy3, 4, 6, 7-tetrachloro-2, 3-dihydrobenzo[b]furan (I) with 4-phenyl- and 4-methylthiosemicarbazides, diphenylthiocarbazone, and also via cyclization of 2, 5-dihydroxy-4, 6, 7-trichloro-3-(N, N-diethyldithio-carbarnoyl)-2, 3dihydrobenzo[b]furan (obtained in the reaction of benzofuran I with sodium NN-dithiocarbamate).Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 463467, April 1996.     

Synthesis of esters of the furan series

Five new esters of the furan series have been synthesized by the reaction of-(5-methyl-2-furyl)propionyl chloride with 2-(3-hydroxypropyl)-furan, 2-(3-hydroxybutyl)tetrahydrofuran, and furfuryl, tetrahydrofurfuryl, and allyl alcohols in the presence of pyridine.