Reactions of nitrophenylpyrimidines with benzyl cyanide. Synthesis of pyrimidinyl-2h-indazoles by the reductive cyclization of substituted dibenzoylazoxybenzenes

The reaction of 2- and 5-(p-nitrophenyl)pyrimidines with benzyl cyanide in a strongly alkaline medium at 65°C gives pyrimidinyl derivatives of dibenzolyazoxybenzene. The conversion of these reagents is low at lower temperatures and a complex product mixture is obtained. The reduction of the azoxybenzene derivatives obtained leads to substituted 2H-indazoles.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 540–546, April, 1995. Original article submitted November 24, 1994. Revision submitted March 10, 1995.     

Mesogenic behaviour of p-nitrophenyl group linked with biphenyl mesogens via flexible spacers

Three series of nematogens with a terminal p-nitrophenyl group linked with biphenyl groups via flexible spacers were synthesised and their transitional properties were studied by means of differential scanning calorimetry (DSC) and polarising microscopy (POM). The nematic–isotropic transition temperature and the associated entropy change showed an odd–even effect as the length of the spacers was varied, in which the even members exhibited higher values. Such an odd–even effect was in consistency with the feature of liquid crystal dimers and trimers. On the basis of these data, it seemed reasonable to assume that the terminal p-nitrophenyl group played a role of mesogen in the nematic liquid crystal. The p-nitrophenyl group may work as a mesogen as a result of the interaction with the biphenyl mesogens. The mesogenic behaviour of the terminal p-nitrophenyl group is explained on the basis of neighbouring group effect.     

Kinetic Effects in non Ionic Micellar Solutions

The elimination reaction between 2-(p-nitrophenyl)ethyl bromide and OH^- ions was studied in nonionic aqueous micellar solutions of two esters of long chain fatty acids and sorbitan polyethylene glycol, Tween 20 (monolaurate) and Tween 80 (monooleate). The equilibrium binding constants of the 2-(p-nitrophenyl)ethyl bromide molecules to the nonionic micellar aggregates were obtained by spectroscopic measurements. The experimental kinetic data were quantitatively rationalized by the treatment of first-order reactions based on the pseudophase model. Results from this work and from previous studies show that, whereas the presence of cationic and sulfobetaine micelles accelerates the reaction, the presence of nonionic micelles inhibits the reaction.     

2-[2-(Dimethylamino)vinyl]-6-pentafluorophenyl-4-phenylpyrylium perchlorate and its hydrolysis products: Synthesis and isomerism

2-(2-(Dimethylamino)vinyll-6 pentafluorophenyl-4-phenylpyryliunt perchlorate has been synthesized and it was shown that it is readily converted into 2-fornrylntethylene-6-pentafluorophenyl-4-phenyl-2H-pyran on chromatography on alkaline Al₂O₃. The stereoisornerism of the synthesized compounds has been studied by PMR spectroscopy.Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences (SO RAN) Novosibirsk 630090. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1188–1194, September, 1996. Original article submitted March 29, 1996.     

Synthesis and liquid crystal properties of substituted 5-(arylcarbonyloxy)-2(p-cyanophenyl)pyrimidines

Liquid crystal p-substituted benzoates, biphenylcarboxylates, and benzoyloxybenzoates were obtained on the basis of 5-hydroxy-2-(p-cyanophenyl)pyrimidine. The development of nematogenicity by the esters due to the p-cyanophenyl grouping was noted, and the appearance of the smectic mesophase by the variation of the ring framework of the acid fragment of the molecule was investigated.Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences (RAN), Novosibirsk 630090. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 371–376, March, 1995. Original article submitted December 19, 1994.     

Uncatalyzed partial oxidation of p-xylene in sub- and supercritical water

In sub- and supercritical water, partial oxidation of p-xylene was performed in a batch reactor without a catalyst at 240-500^oC, 220-300 bar. The loaded amount of hydrogen peroxide was set to 0-100% of the theoretically required oxygen amount. Conversion of p-xylene was reached over 99% within 15-20 min. In sub- and supercritical water, we propose two parallel pathways and major products that consist of p-tolualdehyde, p-toluic acid, terephthalic acid, toluene and benzaldehyde. Yields of major products in subcritical conditions were higher than in a supercritical conditions.     

Interaction of (13S)-6-oxolabd-7,14-dien-13-ol with phenols on the clay askanite-bentonite

The alkylation of some phenols with an allyl 6-oxolabdane alcohol in the presence of the clay askanitebentonite has been investigated. It has been shown that during the reaction intermediateortho- adducts of substitution in the aromatic nucleus are cyclized into chroman derivatives containing a bicyclic terpene residue —2-methyl-2(6-′-oxo-δ^τ-tetranorlabd-12′-yl)chromans. Performing the reaction in the presence of heterogeneous catalysts imposes limitations on the yields of certain products. Novosibirsk Institute of Organic Chemistry, Siberian Division of the Russian Academy of Sciences, Novosibirsk, fax 8(3832) 3 54 752; e-mail: shreerd@nioch.nsc.ru. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 653–662, September–October, 1998.     

Hydrogen exchange,alkylation and acylation of potentially tautomeric methyl and methylidene derivatives of pyridine and diazines (Review)

Summary Data on the deuteration, alkylation and acylation reactions of potentially tautomeric methyl and methylidene derivatives of pyridine, pyrimidine and pyrazine in media of varying acidity and basicity have been collated. Whether these reactions occur via the aromatic tautomers, the more reactive methylidene tautomers or predominantly by generation of mesomeric anions from both tautomers is examined.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 816–829, June, 1995. Original article submitted May 16, 1995.     

Synthesis, Structure, and Derivatives of endo-4-Aminomethyltetracyclo[6.2.1.13,6.02,7]dodec-9-ene

Synthesis was performed and structure studied of endo-4-cyanotetracyclo[6.2.1.1^3,6.0^2,7]dodec-9-ene prepared by reaction of a stereochemically uniform endo-5-cyanobicyclo[2.2.1]hept-2-ene with cyclopentadiene. By analysis of potential energy surface (PES) for reactions of endo-5-cyanobicyclo[2.2.1]hept-2-ene and the respective exo-stereoisomer with cyclopentadiene (in B3LYP/6-31G(d) approximation) the endo,exo-junction and anti-orientation of the methylene bridges in the bicyclic fragments of the adducts were shown to be preferable. Reduction of the tetracyclic nitrile with lithium aluminum hydride yielded endo-4-aminomethyltetracyclo-[6.2.1.1^3,6.0^2,7]dodec-9-ene whose geometry and conformational characteristics were studied by means of molecular mechanics method. Products were obtained from reactions of the tetracyclic amine with p-toluene-, p-chloro-benzene-, p-nitrobenzenesulfonyl chlorides, p-nitrobenzoyl chloride, succinic anhydride, mesityl and p-toluene-sulfonyl isocyanates, phenyl, p-toluenesulfonyl, and benzoyl isothiocyanates, p-nitrophenyloxirane, and N-(2,3-epoxypropyl)carbazole. A series of the amine derivatives was epoxidized with perphtahlic acid. The structure of compounds synthesized was confirmed by analysis of their IR spectra, ¹H, ¹³C, and two-dimensional NMR spectra, and additionally by calculation of the chemical shifts in ¹H and ¹³C NMR spectra by procedures GIAO and CSGT in PBE1PBE/6-31G^## approximation.     

Synthesis and Evaluation of Bioactivity of Thiazolo[3,2‐b]‐[1,2,4]‐triazoles and Isomeric Thiazolo[2,3‐c]‐[1,2,4]‐triazoles

Synthesis of 2‐(o‐nitrophenyl)‐6‐arylthiazolo[3,2‐b]‐[1,2,4]‐triazoles 4 and its isomer 3‐(o‐nitrophenyl)‐5‐arylthiazolo[2,3‐c]‐[1,2,4]‐triazoles 6 has been achieved starting from the appropriate 1‐(o‐nitrobenzoyl)‐3‐thiosemicarbazide 1 . Compound 1 on condensation with α‐haloketones gives 2‐(o‐nitrobenzoyl)hydrazino‐4‐arylthiazole hydrobromide 5 , which, on cyclization with POCl₃, affords thiazolo[3,2‐b]‐[1,2,4]‐triazoles 6 and not the isomeric thiazolo[3,2‐b]‐[1,2,4]‐triazoles 4 . This has been established by an unequivocal synthesis of 4 through polyphosphoric acid cyclization of 5‐aroylmethylmercapto‐3‐o‐nitrophenyl‐[1,2,4]‐triazole 3 . Compound 3 was synthesized by condensation of α‐haloketones with 5‐mercapto‐3‐(o‐nitrophenyl)‐[1,2,4]‐triazole 2 , obtained cyclization of 2‐(o‐nitrobenzoyl)hydrazinecarbothioamide 1 with NaOH. The antibacterial and antifungal activities of some of the compounds have also been evaluated.     

Synthesis and properties of 1-(6-methoxy)-2-benzothiazolyl)-2-pyridones

Substituted ]-(6-methoxy-2-benzothiazolyt)-2-pyridones were prepared from 2-amino-6-methoxybenzathiazate through N-(6-methoxy-2-benzothiazotyl) cyanvorearmileaznd-3-aryl-N-(6-methoxy-2-benzothiazolyt)-2-cyano-2-propenamides. The cyclization of the latter with malonodinitrile in the presence of piperidine gave the corresponding pyridones. The structures of the synthesized compounds were confirmed by¹H NMR and mass spectral data.Department of Organic Chemistry, Mass Spectrometry Laboratory, Slovak Technical University, 812 37 Bratislava, Slovakia. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1402–1404, October, 1995. Original article submitted August 24, 1995.     

Formation of o-nitrosoalkylaminobenzenes in the reaction of benzofurazan s with alcohols in acidic conditions

Summary In the reaction of benzofurazan with isopropanol cyclohexanol o-nitrosoaalkylaminobenzenes are formed besides 2,2-dialkyl-2H-benzimidazole-oxides. In the instance of 4-aminobenzofurazan only 2-nitroso-3-aklaminoanilines are obtained. 5-Nitrobenzofurazan reacts with isopropranol in sulfuric acid to form 4-nitro-2-nitrosoisopropylaminobenzene; however, in the instance of 4-nitrobenzofurazan derivatives the formation of o-nitrosoalkylaminobenzenes has not been observed.Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp, 395–402, March, 1995.Original article submitted January 5, 1995.     

Some reactions of 2-(4-substitutedphenyl)-2-(N-methyl-N-4-substitutedbenzamido) acetic acids

In situ generated 2,4-diaryl substituted münchnones from 2-(4-substitutedphenyl)-2-(N-methyl-N-4-substitutedbenzamido)acetic acids react with acetic anhydride in the presence of 2-nitromethylene thiazolidine, which is most likely acting as a base, and unexpectedly undergo a Dakin–West type reaction and a concurrent autoxidation reaction leading to the formation of (E)-1-(N,4-dimethylbenzamido)-1-(4-fluorophenyl)prop-1-en-2-yl acetate, 4-substitutedphenyl-N-methyl-N-(4-substitutedbenzoyl) benzamides and p-substituted benzoic acids. In addition, a novel and efficient access to N-acyl urea derivatives is described by the reaction between 2-(4-substitutedphenyl)-2-(N-methyl-N-4-substitutedbenzamido)acetic acids and cyclohexyl, isopropyl carbodiimides in the presence of a base. The structures of all new products were identified on the basis of NMR and IR spectra, along with X-ray diffraction data and HRMS measurements.     

Immobilization of a Recombinant Esterase from <Emphasis Type="Italic">Lactobacillus plantarum</Emphasis> on Polypropylene Accurel MP1000

A recombinant esterase from Lactobacillus plantarum was immobilized on hydrophobic support polypropylene Accurel MP1000 by adsorption. Adsorption efficiency was 83%, and the immobilized protein was 12.4 mg/g of support. Esterase activity was determined using p-nitrophenyl butyrate as substrate, and highest activities were observed at 50 °C for immobilized enzyme and 30 °C for free enzyme extract. Concerning thermal stability, after enzyme incubation at 80 °C for 30 min, immobilized and free enzyme retained 91% and 56% of initial activity, respectively. Immobilized enzyme presented lower V _max and higher K _m than free enzyme. Protein was not released from the support, and esterase activity increased after 3 cycles of reuse.     

New derivatives of N-vinyltriazoles: 1,3-diaryl-3-(1H-1,2,4-triazol-1-yl)-2-propen-1-ones

We have synthesized previously unknown N-vinyltriazoles:1,3-diaryl-3-(1H-1,2,4-triazol-1-yl)-2 propen-1-ones. We discuss a hypothesis for a probable reaction mechanism. Institute of Chemistry, Academy of Sciences of the Moldavian Republic, Kishinev 277028. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 910–914, July, 1995. Original article submitted March 24, 1995.     

Synthesis and characterization of diorganotin(IV) complexes of Schiff bases with ONO‐type donors and crystal structure of [N‐(2‐hydroxy‐4‐nitrophenyl)‐3‐ethoxysalicylideneiminato]diphenyltin(IV)

A series of neutral complexes, namely, [N‐(2‐hydroxy‐4‐nitrophenyl)‐3‐hydroxysalicylideneiminato]‐ diphenyltin(IV) ( Ia ), [N‐(2‐hydroxy‐4‐nitrophenyl)‐3‐methoxysalicylideneiminato]diphenyltin(IV) ( IIa ) and [N‐(2‐hydroxy‐4‐nitrophenyl)‐3‐ethoxysalicylideneiminato]diphenyltin(IV) ( IIIa ) were prepared by the reaction of diphenyltin dichloride on the corresponding Schiff bases. The Schiff bases were the reaction products of 2‐hydroxy‐4‐nitroaniline and appropriate salicylaldehydes. All the compounds were characterized by elemental analysis, ¹H‐NMR, ¹³C‐NMR, IR and mass spectroscopy. Compound IIIa was also characterized by single crystal X‐ray diffraction and shows a C₂NO₂ coordination geometry nearly half‐way between a trigonal bipyramidal and square pyramidal arrangement. In the solid state, π? π interactions exist between the aniline fragments of neighbouring molecules. Copyright © 2007 John Wiley & Sons, Ltd.     

2,2-dimethyl-5-(5-r-furfurylidene)-1,3-dioxane4,6 diones 7. Synthesis,structure, and properties of 2,2dimethyl-5-(3-furfuryldiene and 3-thienylidene)-1,3dioxane-4,6-diones

The corresponding 3 furfurylidene(thienylidene)-dioxanediones were obtained by the reaction of 2,5-R,Rfuran(thiophen)-3-carbaldehydes with Meldrum's acid. It was shown by x-ray crystallographic analysis that they have the s-trans disposition at the C₍₂₎=C₍₃₎ bond of the five-membered heterocycle and an exocyclic multiple bond. The character of the conjunction in their molecules was considered in the light of data of x-ray crystallographic analysis, electronic spectra, and NMR. The corresponding 3-furfuryl(thienyl)]dioxanediones were obtained by the selective ionic hydrogenation of the exocyclic double bond.For part 6 see [1]Kuban State Technological University, Krasnodar 350072. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 899–905, July, 1995. Original article submitted October 25, 1994; revision submitted June 5, 1995.     

Donor‐Acceptor‐Functionalized Tetraethynylethenes with Nitrothienyl Substituents: Structure‐Property Relationships

Tetraethynylethenes (TEEs) functionalized with donor (4‐(dimethylamino)phenyl) and acceptor (5‐nitro‐2‐thienyl) groups were prepared by Pd⁰‐catalyzed Sonogashira cross‐coupling reactions (Schemes 1 – 6). The physical properties of these novel chromophores were examined and compared with those of analogous systems containing 4‐nitrophenyl instead of 5‐nitro‐2‐thienyl acceptor groups. X‐Ray crystal‐structure analyses showed the π‐conjugated frameworks of 2 , 11 , and 13 , including the TEE core and all aryl moieties, to be nearly perfectly planar (Figs. 1, 3, and 4). In contrast, one 4‐(dimethylamino)phenyl group in 10 is rotated almost 90° out of the molecular plane, presumably due to crystal‐packing effects (Fig. 2). The analysis of bond lengths and bond angles revealed little, if any, evidence of intramolecular ground‐state donor‐acceptor interactions. The electrochemical behavior of nitrothienyl‐substituted TEEs is similar to that of the corresponding nitrophenyl‐functionalized derivatives (Table 3). The nitrothienyl groups were reduced at −1.23 V (vs. the ferrocene/ferricinium couple, Fc/Fc⁺), regardless of the degree or pattern of other substitutions. For nonsymmetrical TEE 13 , the reduction of the nitrothienyl group at −1.23 V is followed by a reduction of the nitrophenyl group at −1.40 V, a potential typical for the reduction of other nitrophenyl‐substituted TEEs, such as 17 – 20 . UV/VIS Spectroscopy showed a consistently lower‐energy absorption cutoff for nitrothienyl derivatives compared with the analogous nitrophenyl‐substituted TEEs that confirms a lowering of the HOMO‐LUMO gap as a result of nitrothiophene substitution (Figs. 5 and 6). A comparison of the tetrakis‐arylated TEEs 11 , 13 , and 20 clearly showed a steady bathochromic shift of the longest‐wavelength absorption maximum and the end‐absorption upon sequential replacement of nitrophenyl by nitrothienyl groups. Quantum‐chemical computations were performed to explain a number of complex features of the electronic absorption spectra. All empirical features of relevance in the experimental UV/VIS spectra for 2 , 5 , 6 , and 17 – 19 were correctly reproduced by computation (Tables 4 and 5). The combination of theory and experiment was found to be very useful to explain the particular acceptor properties of the 5‐nitro‐2‐thienyl group.     

1-(1-Phthalazinyl)- and 1-(4methoxyphenyl)-6,6dimethyl-4oxo-4,5,6,7-tetrahydroindazole

2-(1-Phthalazinylhydrazino)methylene-(IIIa) or 2-(1-phthalazinylhydrazino)ethylidene-5,5-dimethyl-1,3-cyclohexanediones (IIIb) were prepared from 1-hydrazinophthalazine and 2 formyl- or 2-acetyldimedone. Cyclization of IIIb in the presence ofp- TsOH gave 1-(1-phthalazinyl)3, 6, 6-trimethyl-4-oxo-4, 5, 6, 7-tetrahydroindazole. Reaction of 4-methoxyphenylhydrazine with 2 formyl- and 2-acetyidimedone gave the corresponding 1-(4methoxyphenyl)-4-oxo-4, 5, 6, 7-tetrahydroindazole. In the case of 2 -formyldimedone the intermediate 2-(4methoxyphenylhydrazinomethylene)-5, 5-dimethyl-1,3-cyclohexanedione was isolated.Riga Technological University, Riga LV-1658. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 708–710, May, 1996. Original article submitted December 31, 1995.     

Use of MEKC for the analysis of reactant and product of Baylis–Hillman reaction

A facile, fast and high efficiency micellar EKC has been explored for the analysis and UV detection of p‐nitrobenzaldehyde and 2‐[hydroxy(4‐nitrophenyl)methyl]‐2‐cyclopenten‐1‐one with a buffer electrolyte of 30.0 mM tetraborate and 50.0 mM sodium taurodeoxycholate at pH 9.3. Under the optimal conditions, a linear range from 7.8×10^–2 to 5.0×10² mM for those analytes (r² > 0.99) was achieved. The LOD was 3.9 μM for 2‐[hydroxy(4‐nitrophenyl)methyl]‐2‐cyclopenten‐1‐one and 7.8 μM for p‐nitrobenzaldehyde, respectively (S/N = 3). The applicability of this new method for the analysis of reactants (p‐nitrobenzaldehyde and cyclopent‐2‐enone), catalysts (imidazole or N‐methyl imidazole or 1‐benzyl‐imidazole) and product (2‐[hydroxy(4‐nitrophenyl)methyl]‐2‐cyclopenten‐1‐one) on offline Baylis–Hillman reaction was examined. The relationship between the reaction time and the amount of product has been studied. Meanwhile, three different kinds of catalysts were investigated for getting the desired moderate to good amount products. It was found that comparing with N‐methyl imidazole or 1‐benzyl‐imidazole catalyst, imidazole‐catalyzed reaction could produce more products within the same reaction time. Furthermore, the results indicated that the rate law for the investigated Baylis–Hillman reaction was second‐order reaction. The rate constant for the reaction is 1.34 (±0.01)×10^–3 mol^–1 m³/s.