Synthesis and liquid-crystal properties of aryl esters of p-(5-alkyl-2-pyrimidinyl)benzoic acids

Aryl esters of p-(5-alkyl-2-pyriraidinyl)benzoic and p-(5-alkyl-2-pyrimidinyl)-benzoyloxybenzoic acids, which displayed nematic properties with broad ranges of the existence of a meso phase, particularly in the case of the diesters (up to 140–170C), were obtained. It is shown that the presence of a 2-phenyl group in the pyrimidine ring favors the development of a liquid-crystal state as compared with 5-phenylpyrimidines.DeceasedTranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1636–1639, December, 1988     

Chemo- and diastereoselective control for a flexible approach to (5S,6S)-6-alkyl-5-benzyloxy-2-piperidinones

Chemo- and diastereoselective transformation of the N,O-acetals and their chain tautomers (4/5), readily derived from protected 3-hydroxyglutarimide 1a, was studied. It was uncovered that while the reaction with a combination of boron trifluoride etherate/zinc borohydride led to cyclic products (5S,6S/R)-6-alkyl-5-benzyloxy-2-piperidinones 3/2, and 6 in modest chemo- and diastereoselectivities, the reaction of 4/5 with zinc borohydride led exclusively to the formation of the ring-opening products 6 in excellent anti-diastereoselectivities. On the basis of the latter reaction, a flexible approach to (5S,6S)-6-alkyl-5-benzyloxy-2-piperidinones 3 was disclosed.     

Synthesis,structure, and stereochemistry of 2-alkyl-4,4,5-trimethyl- and 2-alkyl-4,4,6,6-tetramethyl-1,3-dioxanium perchlorates

A number of 2-alkyl-4,4,5-trimethyl- and 2-alkyl-4,4,6,6-tetramethyl-1,3-dioxanium perchlorates were obtained by acylation of 1,3-diols in the presence of 70% perchloric acid. Acid-catalytic cleavage of the heteroring with subsequent cyclization to 2-alkyl-1,3-dioxanium perchlorates occur in the reaction of 2-aryl(alkyl)-substituted and 2-unsubstituted 1,3-dioxanes with carboxylic acid anhydrides and 70% HClO₄. Hypothetical detachment of a hydride ion by means of the acceptor acylium cation does not occur under the investigated conditions. The structures of the synthesized perchlorates were studied by PMR spectroscopy and it was shown that 1,3-dioxanium cations at room temperature exist in a state of rapid conformational isomerization of the chair-chair form. The rate of interconversion of the 2,4,4-trimethyl-1,3-dioxanium cation decreases appreciably as the temperature is reduced to –90°. as evidenced by marked broadening of the lines of the protons of the gemdimethyl groupings.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 182–186, February, 1977.     

3-Bromo-propenyl acetate in organic synthesis: an expeditious route to 3-alkyl-4-acetoxy-5-iodomethyl isoxazolidines

N-Trimethylsilyloxy-N-benzyl-1-alkyl-2-acetoxy-3-buten-1-amines 13, obtained in good yields and moderate diastereoselectivities by TMSOTf promoted α-acetoxyallylation of nitrones using metallic zinc and 3-bromo-propenyl acetate 11, are exploited in a stereospecific 5-exo-trig iodocyclization reaction to afford 4,5-cis-3-alkyl-4-acetoxy-5-iodomethyl isoxazolidines 14, promising starting materials for the synthesis of pyrrolidine azasugars.     

Chemical reactions of 5-alkyl-1,4-diaza- and 5-alkyl-1-aza-4-oxabicyclo[3.3.0]octan-8-ones

The behavior of 5-alkyl-1,4-diaza and 5-alkyl-1-aza-4-oxabicyclo[3.3.0]octan-8-ones has been studied towards catalytic reduction, reduction by lithium aluminum hydride, acylation, cyanoethylation, alkylation, etc. The oxazolidine ring in 5-alkyl-1-aza-4-oxabicyclo[3.3.0]octan-8-ones was readily opened by electrophilic and nucleophilic reagents whereas most of the reactions of 5-alkyl-1,4-diazabi-cyclo[3.3.0]octan-8-ones occurred with retention of the bicyclic structure.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 193–197, February, 1988.     

Kinetics of nucleophilic halogen exchange in 1-alkyl-2-(5′ -halo-2′- furyl) benzimidazoles

The kinetics of the reaction of 1-alkyl-2-(5-halo-2-furyl)benzimidazoles and their corresponding quaternary salts with secondary aliphatic amines were studied. The effect on the activation parameters of this reaction of the nature of the halogen being replaced by the secondary amine residue, the presence of a positive charge on the imidazole ring, the character of the anion in the quaternary salts, and the remoteness of the reaction center from the activating grouping on the activation parameters of this reaction is discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 252–257, February, 1971.     

Reactivities of 5-alkyl-2-thioxopyrrolidines

The chemical transformations of 5-alkyl-2-thioxopyrrolidines with nucleophilic and electrophilic reagents were studied and compared with the reactivities of their oxygen analogs. On the basis of the experimental data obtained from alkylation, hydroxyethylation, and condensation reactions it was established that, depending on the conditions and the character of the reagent, 5-alkyl-2-thioxopyrrolidines undergo the indicated reactions in the thiolactam or thiolactin form.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1648–1651, December, 1979Original article submitted November 25, 1978.     

Synthesis and stereochemistry of 1-alkyl-2-methoxycarbonyl-3-phenylaziridines

Mixtures of cis- and trans-1-alkyl-2-methoxycarbonyl-3-phenylaziridines are formed in the reaction of methyl -bromocinnmate with excess amine, amino alcohol, and amino acid methyl ester hydrochloride. The ratios of the isomers depend on the solvent used.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 937–939, July, 1980.     

New synthesis of 4-alkyl-3-cyanocoumarins

A new procedure has been developed for the synthesis of 4-alkyl-6,8-dibromo-7-hydroxy-2-oxo-2H-chromene-3-carbonitriles by bromination of 2-amino-4-alkyl-4H-chromene-3-carbonitriles with bromine in acetic acid, followed by hydrolysis.     

Synthesis and anti-TMV activity of novel N-(3-alkyl-1H-pyrazol-4-yl)-3-alkyl-4-substituted-1H-pyrazole-5-carboxamides

In order to investigate the biological activity of novel bis-pyrazole compounds,a series of N-（3-alkyl-5-（N-methylcarbamyl）- 1H-pyrazol-4-yl）-3-alkyl-4-substituted-1H-pyrazole-5-carboxamides were designed and synthesized with ethyl 3-alkyl-1H-pyrazole -5-carboxylate 1 as starting materials.N-Methyl-3-alkyl-4-amino-1H-pyrazole-5-carboxamides 6 were obtained from 1 via 5 steps.3-Alkyl-4-substitued-1H-pyrazole-5-carboxyl chlorides 4a,4b,11a,11b,11c or 12 were also obtained from 1 via several steps.Target compounds 7a-7g were obtained after the reaction of 6 with the above 1H-pyrazole-5-carboxyl chlorides.Preliminary bioassay showed some compounds possessing good inactivation effect against TMV（tobacco mosaic virus）.Compound 7a showed higher activity superior to ningnanmycin at a concentration of 5.0×10^-4 g/mL and equal activity at 1.0×10^-4 g/mL;7b and 7c showed equal activity to virazole both at concentrations of 5.0×10^-4 g/mL and 1.0×10^-4 g/mL.     

Synthesis of mesomorphic 2-alkyl-5-(p-cyanophenyl)pyridines

A new series of liquid-crystal derivatives of 2-alkyl-5-(p-cyanophenyl)pyridines were obtained by halogenation of 2-alkyl-5-phenylpyridines under the conditions of the Birckenbach-Gubo-Waters reaction with subsequent conversion of the 2-alkyl-5-(p-bromo- or iodophenyl) pyridines to the cyano derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 85–88, January, 1981.     

Synthesis of 5-alkyl-1,3,5-triazinan-2-ones and 5-alkyl-1,3,5-triazinane-2-thiones using Cu- and Sm-containing catalysts

Efficient procedures have been developed for the synthesis of 5-alkyl-1,3,5-triazinan-2-ones and 5-alkyl-1,3,5-triazinane-2-thiones by reaction of urea (thiourea) with primary alkylamines and N,N,N′,N′-tetramethylmethylenediamine and by reaction of primary amines with N,N′-bis(dimethylaminomethyl)urea(thiourea) in the presence of Cu- and Sm-containing catalysts.     

Regioselective synthesis of 5-alkylsalicylates, 5-alkyl-2-hydroxy-acetophenones, and 5-alkyl-2-hydroxy-benzophenones by [3 + 3] cyclization of 1,3-bis(silyl enol ethers) with 2-alkyl-1,1,3,3-tetraethoxypropanes

A variety of 5-alkylsalicylates, 5-alkyl-2-hydroxy-acetophenones, and 5-alkyl-2-hydroxy-benzophenones was regioselectively prepared by TiCl4 mediated formal [3 + 3] cyclization of 1,3-bis(silyl enol ethers) with 2-alkyl-1,1,3,3-tetraethoxypropanes.     

Direct nitration and acetylation of the furan nucleus of 1-alkyl-2-[Β -(2′-furyl) vinyl]-benzimidazoles

The direct nitration and acetylation of 1-methyl-, 1-ethyl-, and 1-benzyl-2-[-(2-furyl)vinyl]benzimidazoles has given the corresponding 1-alkyl- and 1-benzyl-2-[-(5-nitro-2-furyl)vinyl]benzimidazoles and 1-alkyl- and 1-benzyl-2-[-(5-acetyl-2-furyl)vinyl]benzimidazoles. The UV spectra of these compounds have been recorded and their ionization constants have been determined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 6, pp. 832–834, June, 1970.     

Coordination compounds of hydrazine derivatives with transition metals. Part 27. Coordination chemistry of 4-amino-3-alkyl-5-thio-1,2,4-triazolines and 4-amino-5-oxo-3-thioxo-6-alkyl-2,3,4,5-tetrahydro-1,2,4-triazines

Summary Mono-, bis- and tris-ligand nickel(II) and cobalt(II) complexes with 4 amino-3-alkyl-5-thio-1,2,4-triazolines (HRL) (R=H, Me, or Et) and 4-amino-5-oxo-3-thioxo-6-methyl-2,3,4,5-tetrahydro-1,2,4-triazine (HL') have been prepared and characterized. In these complexes both HRL and HL' are in the neutral thione form. Nickel(II) and cobalt(II) complexes with mononegative thiolate ligands have been also isolated.The reaction of HL' with copper(II) salts in a molar ration of 11 results in the formation of [Cu(HL')X] (X=Cl or Br) and Cu(L')X (X=NO₃ or CH₃COO). However, in the presence of a large excess of HL' the reaction proceeds with partial reduction of Cu^II and both [Cu(HL')X₂] and [Cu(HL')₂]X have been isolated and characterized. The mechanism of copper(II) reduction by HL' is discussed.     

The use of aliphatic aldehydes for the synthesis of 4-alkyl-6-amino- 3,5-dicyanopyridine-2(1H)-thiones

The condensation of aliphatic aldehydes with malononitrile and cyanothioacetamide gives 4-alkyl-2,6-diamino-3,5-dicyano-4H-thiopyrans which recyclize into 4-alkyl-6-amino3,5-dicyanopyridine-2(IH)-thiones. The latter are easily S-alkylated with -haloacetonitriles and -haloacetophenones.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 938–942, April, 1996     

A one-step synthesis of 2-Alkyl-5-hydroxychromones and 3-Alkoyl-2-alkyl-5-hydroxychromones

2-Alkyl-5-hydroxychromones (2-alkyl-5-hydroxy-4-oxo-4H-1-benzopyran) and 3-alkoyl-2-alkyl-5-hydroxychromones (3-alkoyl-2-alkyl-5-hydroxy-4-oxo-4H-1-benzopyran) were prepared in one-step and one pot reaction by condensation of 2',6'-dihydroxyacetophenone with an alkoyl chloride in the presence of K2CO3.     

An unusual synthetic way to 2-methyl-3-alkyl-6-ethoxy-heptan-2-ols from 2-ethoxy-5-alkyl-3,4-dihydro-2H-pyrans

A simple and swift preparation of 2-methyl-3-alkyl-6-ethoxyheptan-2-ols may be accomplished in two steps starting from 2-ethoxy-5-alkyl-3-,4-dihydro-2H-pyrans via chlorination of the heterocyclic compounds and subsequent reaction with MeMgBr.     

Alkaline scission of a urea unit in 5-alkyl-2-amino-N-ureido-3,4-dicyanopyrroles

The scission of the urea group in 5-alkyl-2-amino-3,4-dicyano-N-ureidopyrroles on boiling in KOH solution in DMSO was observed to give 5-alkyl-1,2-diamino-3,4-dicyanopyrroles which were used for the synthesis of pyrrolo[1,2-b][1,2,4]triazepines by reaction with acetylacetone.I. N. Ul'yanov Chuvash State University, Cheboksary 428015, Russia; e-mail: anatoly5@chuvsu.ru. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, 611–616, May, 2000.     

Transformations of 3-alkyl-4-(methoxyphenyl)-1<Emphasis Type="Italic">H</Emphasis>-pyrazole-5-diazonium salts

The coupling of 3-alkyl-4-(methoxyphenyl)-1H-pyrazole-5-diazonium salts with acetylacetone followed by cyclization of the formed heterylhydrazones resulted in pyrazolo[5,1-c][1,2,4]triazines. The 4-(3,4-dimethoxyphenyl)-3-methyl-1H-pyrazole-5-diazonium salt was not involved into a similar reaction but suffered an intramolecular azo coupling giving pyrazolo[3,4-c]-cinnoline.