Synthesis of 2-(5-halogeno-2-f uryl)-2,3-dihydroperimidines

By boiling naphthylene-1,8-diamine with 5-halogeno- and 5-nitrofurfural in benzene or xylene, 90–95% yields of the corresponding 2-(5-halogeno-2-furyl)- and 2-(5-nitro-2-furyl)-2, 3-dihydroperimidines have been obtained. The dehydrogenation of 2-(5-bromo-2-furyl)-2, 3-dihydroperimidine with palladium on carbon has given 2-(5-bromo-2-furyl)perimidine. The compounds obtained have been characterized by their UV and IR spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1001–1003, July, 1973.     

Synthesis and establishment of the structures of 5-hydroxy-and 8-hydroxy -2-(2-furyl) quinoxaline

Two condensation products — 5-hydroxy-2-(2'-furyl)quinoxaline and 8-hydroxy-2-(2-furyl)-quinoxaline — are formed in the reaction of 2-furylglyoxal or the sodium salt of its aldoxime with 6-hydroxy-1,2-diaminobenzene. Dielcometry was used to establish the position of the substituent in the benzene ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 306–310, March, 1976.Deceased.     

Synthesis and transformations of 2-(2-furyl)-and 2-[β-(2-furyl)vinyl]imidazo[4,5-b]phenazines

The corresponding 2-(2-furyl)- and 2-[-(2-furyl)vinyl]imidazo[4,5-b]phenazines were obtained by the condensation of 2,3-diaminophenazine with furfural and 2-furylacrolein and with their 5-bromo and 5-nitro derivatives. The phenazines were also synthesized by the reaction of 2-methylimidazo[4,5-b]phenazine with furfural and 5-bromo- and 5-nitrofurfural. The alkylation, acetylation, and nitration of the compounds obtained, as well as replacement of the halogen in the furan ring by a nitro group, were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1425–1428, October, 1971.     

Synthesis and properties of 5-(5-nitro-2-furyl)thiazolines

The reactions of 2-amino-4-methyl-5-(5-nitro-2-furyl)thiazole with excess methyl iodide leads to 3,4-dimethyl-2-methylamino-5-(5-nitro-2-furyl)thiazolium iodide, which is converted to 2-imino-3,4-dimethyl-5-(5-nitro-2-furyl)thiazoline under the influence of bases. The iminothiazoline structure was proved by comparison of the spectral characteristics of its acetyl derivative and the isomeric 2-(N-acetyl-N-methyl) amino-4-methyl-5-(5-nitro-2-furyl)thiazole. The pKa values of 2-amino-4-methyl-5-(5-nitro-2-furyl)thiazole and 3,4-dimethyl-2-imino-5-(5-nitro-2-furyl)-thiazoline were determined, and the constant of the aminothiazole-iminothiazoline tautomeric equilibrium was calculated.Translated from Khimiya Geterosiklicheskikh Soedinenii, No. 10, pp. 1337–1340, October, 1985.     

Synthesis and transformations of 2-(2-furyl)-and 2-[β;-(2-furyl)vinyl]naphth[1,2-d]imidazoles

The corresponding 2-(2-furyl)naphth[1,2-d]imidazoles were obtained by heating Schiff bases, prepared from 1,2-naphthalenediamine and furfural and 5-bromo- and 5-nitrofurfurals, in nitrobenzene. 2-[-(2-Furyl)vinyl]naphth[1,2-d]imidazoles were synthesized by condensation of 2-methylnaphth[1,2-d]imidazole with furfural and 5-bromo- and 5-nitrofurfural. The methylation, nitration, and acetylation of the compounds obtained were studied, and the replacement of the bromine atom in the furan ring by a nitro group was also investigated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1555–1557, November, 1972.     

Studies on furan derivatives. V. A novel ethoxycarbonylmethylation of the 5-nitro-2-furan ring in the reaction of α-(2-furyl)-β-(5-nitro-2-furyl)ethynyl with N-ethoxycarbonylmethylpyridinium ylide

An unexpected product, 1-(4-ethoxycarbonylmethyl-5-nitro-2-furyl)-2-(2-furyl)-3-ethoxycarbonyl-indolizine was obtained by the reaction of α-(2-furyl)-β-(5-nitro-2-furyl)ethynyl with N-ethoxy-carbonylmethylpyridinium ylide in N,N-dimethylformamide, together with 1-(5-nitro-2-furyl)-2-(2-furyl)-3-ethoxycarbonylindolizine.     

Synthesis and methylation products of 4(5)-(2-furyl)imidazole

Bromination of 2-acetylfuran with copper(II) bromide in a mixture of ethyl acetate and chloroform leads selectively to furacyl bromide, the nucleophilic substitution of bromine in which by OAc and subsequent use of the Weidenhagen reaction enabled the synthesis of 4(5)-(2-furyl)imidazole. On N-methylation of this imidazole in KOH–acetone 2 isomers are formed, the 1-methyl-4- and 1-methyl-5-(2-furyl)imidazoles. It was established that, unlike alkylation of 4(5)-phenylimidazole, the main product of the reaction is 1-methyl-5-(2-furyl)imidazole.     

Highly effective stereoselective synthesis of vinyl ethers of 5-alkyl-2-(2-furyl)-5-hydroxymethyl-1,3-dioxanes

The vinylation of cis-5-alkyl-5-hydroxymethyl-2-(2-furyl)-1,3-dioxanes in the KOH–DMSO system in acetylene at atmospheric or elevated pressures (85-100°C, 3 h) takes place stereoselectively and leads to the formation of cis-5-alkyl-2-(2-furyl)-5-vinyloxymethyl-1,3-dioxanes with yields of up to 93%.     

Nitration of 2- and 4-[2-(2-furyl)vinyl]thiazole derivatives

Nitration of 4-methyl-2-[2-(nitro-2-furyl)vinyl]thiazole with a mixture of concentrated nitric and sulfuric acids leads to 4-methyl-5-nitro-2-[2-(3,5-dinitro-2-furyl)vinyl]thiazole. Under the same conditions 2-methyl- and 2-acetamido-4-[1-R-2-(5-nitro-2-furyl)vinyl]thiazoles (R=CH₃, Cl) are nitrated in the 3 position of the furan ring, 2-amino-4-[1-chloro-2-(5-nitro-2-furyl)vinyl]thiazole is nitrated in the 5 position of the thiazole ring and 2-acetamido-5-nitro-4-[2-(2-furyl)vinyl]thiazole undergoes profound changes. Under the influence of a mixture of of nitric acid and acetic anhydride the latter compound is converted quantitatively to the 5-nitro derivative (with respect to the furan ring), whereas 4-[2-(5-nitro-2-furyl)vinyl]thiazole derivatives do not undergo reaction.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 314–317, March, 1977.     

Synthesis and properties of 2-amino-5-(5-nitro-2-furyl) thiazole derivatives

The hydrochlorides of the corresponding 2-aminothiazoles, which were converted to the free bases, were obtained by hydrolysis of 2-acylamino-5-(5-nitro-2-furyl) thiazoles. Reactions that take place at the amino group of 2-amino-5-(5-nitro-2-furyl)thiazoles are described.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1038–1041, August, 1985.     

Greenish metal-lustrous organic crystals formed from 1-aryl-2-(2-thienyl)-5-(5-tricyanoethenyl-2-furyl)pyrroles

On the treatment of 1-aryl-2-(2-furyl)-5-(2-thienyl)pyrroles with tetracyanoethylene, 1-aryl-2-(2-thienyl)-5-(5-tricyanoethenyl-2-furyl)pyrroles were produced. These compounds formed crystals with greenish metallic luster. In their solid-state UV-vis-NIR diffuse reflection-absorption spectra, absorption band corresponding to metallic reflection spreads in the range of 550-900 nm. Furthermore, strong absorption appeared below 520-540 nm. This absorption results in the appearance of green color. Single-crystal X-ray crystallographic analysis revealed the crystal structure of 1-(4-methoxyphenyl)-2-(2-thienyl)-5-(5-tricyanoethenyl-2-furyl)pyrrole (2c). The distinct features of the crystal structure are as follows: (1) the thiophene-pyrrole-furan-tricyanoethenyl π-system is approximately flat; (2) the conformational relation between the pyrrole ring and the furan ring is anti, that is, these rings are pointing in opposite directions and the dihedral angle of N-C-C-O=180°; (3) as a result, the tricyanoethenyl group is far from the 4-methoxyphenyl group; (4) the molecules of 2c are arranged in a ribbon structure; (5) the ribbons are assembled side-by-side to form a terraced layer; (6) the layers stack so that the π-orbitals of 2c become close to each other.     

Syntheses of various 5-(bromoaryl)-substituted uracils

The Suzuki Pd(0)-catalyzed coupling between arylboronic acids and aryl bromides or iodides in weakly alkaline medium, previously further developed by us, has been used for regioselective preparation of 5-(2′-bromo-5′-furyl)-, 5-(2′-bromo-4′-furyl)-, 5-(2′-bromo-5′-thienyl)-, 5-(2′-bromo-4′-thienyl)-, 5-(4′-bromo-2′-thiazolyl)-, 5-(3′-bromophenyl)-, 5-(6′-bromo-2′-pyridyl)- and 5-(4′-bromo-2′-pyrimidyl)-substituted 2,4-di-t-butoxypyrimidines. In the coupling between 2,4-di-t-butoxy-5-pyrimidineboronic acid and the nine different aryl dibromides that were tried as coupling partners, only the 2,4- and 2,5-dibromothiazoles did not give satisfactory yields, 15% and 0%, respectively. The other seven aryl dibromides gave the desired 5-(bromoaryl)-2,4-di-t-butoxypyrimidines in 58-89% yield. Attempts to synthesise 2,4-di-t-butoxy-5-(2′-bromo-4′-thienyl)pyrimidine from 2-bromo-4-iodothiophene failed. Dealkylation of the 5-(bromoaryl)-2,4-di-t-butoxypyrimidines in 2.5 M hydrochloric acid gave the corresponding 5-(bromoaryl)uracils in almost quantitative yields.     

5-Methyl-2-furylglyoxal, 5-Methyl-4-nitro-2-furylglyoxal, and Their Derivatives. Nitration of 2-(5-Methyl-2-furyl)quinoxaline

The oxidation of 2-acetyl-5-methyl-4-R-furans (R = H, NO₂) by selenious acid was studied. Derivatives substituted at the C=O groups of the corresponding glyoxals were obtained. The nitration of 2-(5-methyl-2-furyl)quinoxaline was carried out at C_(4'). Oxidative splitting of the -nitrofuryl group occurs at the C₍₄₎-C₍₅₎ and C₍₅₎-O bonds.     

Synthesis of 2-phenyl-3-(2-furyl) — and 2-phenyl-3-[β-(2-furyl)vinyl]-1,2-dihydro-naphtho[1,2-d]-1,2,4-triazines

The corresponding 2-phenyl-3-(2-furyl)- and 2-phenyl-3-[-(2-furyl)vinyl]-1,2-dihydronaphtho-[1,2-d]-1,2,4-triazines were obtained by heating Schiff bases [prepared by reaction of 1-(phenyl-azo)-2-aminonaphthalene with furfural, -(2-furyl)acrolein, and their 5-bromo and 5-nitro derivatives] in glacial acetic acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 158–160, February, 1973.     

Synthesis and transformations of 2-(2-furyl)- and 2-[β-(2-furyl)vinyl] phenanthr [9,10]imidazoles

The corresponding 2-(2-furyl)- and 2-[-(2-furyl)vinyl] phenanthr[9,10]imidazoles were obtained by the condensation of 9,10 phenanthrenequinone with furfural, -(2-furyl)acrolein, and their 5-bromo and 5-nitro derivatives in the presence of ammonium acetate in glacial acetic acid. Their metallation, acetylation, nitration, and replacement of halogen by a nitro group were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1014–1016, August, 1971.     

Aminomethylation of 2-(2-furyl)imidazo-[1,2-a]pyridine

The aminomethylation (morpholino- and piperidinomethylation) of 2-(2-furyl)imidazo[1,2-a]-pyridine proceeds primarily at the 3 position of the imidazopyridine system at equimolecular ratios of the reagents, but also proceeds at the 5 position of the furan ring when there is a slight excess of formaldehyde and amine. The structure of the product of monomorpholinomethylation was proved by nitration to give a mononitro derivative that was identical to the 3-morpholinomethyl-2-(5-nitro-2-furyl)imidazo[1,2-a]pyridine prepared by the morpholinomethylation of 2-(5-nitro-2-furyl)imidazo[1,2-a]pyridine. Thin-layer chromatography and IR and UV spectroscopy were used to prove the structures.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 818–821, June, 1971.     

New approach to the synthesis of substituted 5-arylcarbamoyl-3-cyano-6-methylpyridine-2(1h)-thiones. Molecular and crystal structure of 2-allylthio-3-cyano-5-(2-methoxyphenylcarbamoyl)-6-methyl-4-(5-methyl-2-furyl)-1,4-dihydropyridine

Morpholinium 5-arylcarbamoyl-3-cyano-6-methyl-4-(5-methyl-2-furyl)-1,4-dihydropyridine-2-thiolates have been obtained by the interaction of enamines of acetoacetanilides with 5-methyl-2-furfurylidenecyanothioacetamide. Alkylation of the salts gives thioethers and oxidation gives the corresponding substituted pyridine-2(1H)-thiones. The structure of 2-allylthio-3-cyano-5-(2-methoxyphenylcarbamoyl)-6-methyl-4-(5-methyl-2-furyl)-1,4-dihydropyridine was studied by X-ray crystallographic analysis. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 51–58, January, 2006.     

Three-component condensation of 2-naphthylamine with aromatic aldehydes and 5-(2-furyl)-1,3-cyclohexanedione

Three-component condensation of 5-(2-furyl)-1,3-cyclohexanedione with 2-naphthylamine and aromatic or heteroaromatic aldehydes afforded 12-aryl(hetaryl)-9-(2-furyl)-7,8,9,10,11,12-hexahydrobenzo[a]-acridin-11-ones possessing two asymmetric carbon atoms (C⁹ and C¹²). The products were found to be formed as mixtures of diastereoisomers.     

Synthesis of 9-(5-Pentyl-2-furyl)nonanoic Acid

Recently,severalkindsoftotalsyntheticmethodsfornaturallyoccurringfuranoidfattyacids(F-acids)whichhavemanybiologicalactivities1havebeendeveloped2.Inthepresentpapertheauthorswishtoreportanewsimplerouteofsynthesizing9-(5-pentyl-carbomethoxyheptyl)triphenylphosphoniumbromideinthepresenceofpotassiumcarbonateandl,2-butyleneoxideinanunexpectedlylowyield(34%),mainlyduetotheextremelyunstablecharacterof2inbasicconditions,especiallyforstrongbaselikesodiummethoxidewhichgaverisetoconsiderableresinification…     

Synthesis and properties of 1-methyl-2-phenyl-5-(2-furyl)- and 1-methyl-2-phenyl-5-(2-thienyl)imidazoles

2-Phenyl-5-(2-furyl)- and 2-phenyl-5-(2-thienyl)imidazoles were synthesized by condensation of 2-furoylmethyl and 2-thenoylmethyl acetates with benzaldehyde under the conditions of Weidenhagen reaction. The products were converted to N-methyl derivatives in the KOH-acetone system. The electrophilic substitution reactions of the products (acylation, bromination, nitration, sulfonation, hydroxymethylation) were studied.