Vanilline Alkanoates in the Synthesis of Hexahydrobenzacridine and Octahydroxanthene Derivatives

Cascade heterocyclization of 1,3-cyclohexanedione and dimedone with 2-naphthylamine and vanilline esters gave derivatives of 2-methoxy-4-(alkyl-11-oxo-7,8,9,10,11,12-hexahydrobenz[a]acridin-12-yl)- and 2-methoxy-4-(alkyl-1,8-dioxo-2,3,4,5,6,7,8,9-octahydro-1H-xanthen-9-yl)phenyl esters of aliphatic (C₁– C₄ ) carboxylic acids.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 4, 2005, pp. 654–658.Original Russian Text Copyright © 2005 by Kozlov, Basalaeva.     

X-ray studies of three 3,6-bis(pyridin-2-yl)-1,2,4,5-tetrazine cocrystals: an unexpected molecular conformation stabilized by hydrogen bonds

The results of the X-ray structure analysis of three novel 3,6-bis(pyridin-2-yl)-1,2,4,5-tetrazine cocrystals are presented. These are 3,6-bis(pyridin-2-yl)-1,2,4,5-tetrazine–2,4,6-tribromophenol (1/2), C₁₂H₈N₆·2C₆H₃Br₃O, 3,6-bis(pyridin-2-yl)-1,2,4,5-tetrazine–isonicotinic acid N-oxide (1/2), C₁₂H₈N₆·2C₆H₅NO₃, and 3,6-bis(pyridin-2-yl)-1,2,4,5-tetrazine–4-nitrobenzenesulfonamide (1/1), C₁₂H₈N₆·C₆H₆N₂O₄S. Special attention is paid to a conformational analysis of the title tetrazine molecule in known crystal structures. Quantum chemistry methods are used to compare the energetic parameters of the investigated conformations. A structural analysis of the hydrogen and halogen bonds with acceptor aromatic tetrazine and pyrazine rings is conducted in order to elucidate factors responsible for conformational stability.     

A facile synthesis of novel 3-(aryl/alkyl-2-ylmethyl)-2-thioxothiazolidin-4-ones using microwave heating

(Z)-5-(2-(1H-Indol-3-yl)-2-oxoethylidene)-3-(aryl/alkyl-2-ylmethyl)-2-thioxothiazolidin-4-ones (7a–w) have been synthesized by the Knoevenagel condensation reaction of 3-(aryl/alkyl-2-ylmethyl)-2-thioxothiazolidin-4-ones (3a–d) with suitably substituted 2-(1H-indol-3-yl)2-oxoacetaldehydes (6a–g) under microwave conditions. The thioxothiazolidin-4-ones were prepared from the corresponding aryl/alkyl amines (1a–d) and di-(carboxymethyl)-trithiocarbonyl (2). The aldehydes (6a–g) were synthesized from the corresponding acid chlorides (5a–g) using HsnBu₃.     

Rearrangements of N-alkyl-/aryl-nitrones derived from 4-oxo-4H-1-benzopyran-3-carboxaldehyde--a solvent-dependent process

C-(4-Oxo-4H-1-benzopyran-3-yl)-N-alkyl-/aryl-nitrones derived from 4-oxo-4H-1-benzopyran-3-carboxaldehyde, rearrange to 2-alkyl-/aryl-amino-3-formylchromone and/or 3-(alkyl-/aryl-aminomethylene)chroman-2,4-dione depending upon the reaction medium. 3-(Alkylaminomethylene)chroman-2,4-dione has been utilized in the synthesis of 1-benzopyrano[3,4-d]isoxazole-4-one.     

Chemotherapeutic agents. IX. Synthesis and pesticidal activities of bis[4-aryl/alkyl-1, 2, 4-triazoline-5-thione-3-yl]alkanes and 1 -Aryl/alkyl-3-[4-(4-aryl/alkyl-1, 2, 4-triazoline-5-thione-3-yl)phenyl]thiourea and related compounds

Various bis[4-aryl/alkyl-1, 2, 4-triazoline-5-thione-3-yl]alkanes ( 3 ) were prepared from base cyclization of bis thiosemicarbazide 2 and transformed into sulphides by reaction with different alkyl halides in alkaline medium. These compounds were further oxidised to sulphones 5 with acidic potassium permanganate. 1-Aryl-3-[4-(4-aryl/alkyl-1, 2, 4-triazoline-3-thione-5-yl)phenyl]thioureas ( 8 ) were prepared in two steps from p-aminophenylhydrazide ( 6 ) and aryl/alkylisothiocyanates. Alkylation of 8 with different alkyl halides yielded exclusively sulphides 9 . Some sulphides 12 and Mannich bases 13 from 5-(p-fluorophenyl)-1, 3, 4-oxadiazol-2-thione ( 11 ) were also prepared to evaluate their pesticidal activities. All the prepared compounds were screened for pesticidal activities but none of them exhibited any significant activity.     

Mass spectra of halogenated esters 5—Chloromethyl esters of aliphatic C2?C12 n-carboxylic acids and their monochlorinated derivatives

A study has been made of the mass spectral fragmentation upon electron impact of aliphatic C₂? C₁₂ chloromethyl esters and all their 66 monochlorinated derivatives. The fragmentation pathways of the parent chloromethyl esters were elucidated with the aid of the 1st FFR metastable ions. A McLafferty rearrangement gives the base peak in the C₆? C₁₁ parent esters and in almost all the 4-chloro and ω-chloro isomers. The subsequent loss of HCl gives a very characteristic peak of the chloromethyl esters and their (3-ω)-chloro derivatives at m/z 72, [C₃H₄O₂]⁺. The 2-chloro isomers have the corresponding chlorine-containing fragment ion at m/z 106/108. The mass spectra of 2-, 3-, 4-, 5- and ω-chloro isomers give the characteristic fragment ions, the mass spectra of the other isomers being very similar.     

Chinazolincarbonsäuren. VII. Mitteilung. Ein einfacher Zugang zu (4-Oxo-3,4-dihydrochinazolin-3-yl)-alkansäuren, (4-Oxo-3,4-dihydro-1,2,3-benzotriazin-3-yl)-alkansäuren und deren Estern

Quinazoline Carboxylic Acids. An Easy Route to (4-Oxo-3,4-dihydroquinazolin-3-yl)-alkanoic Acids, (4-Oxo-3,4-dihydro-1,2,3-benzotriazin-3-yl)-alkanoic Acids and their Esters A new route was found for the synthesis of (4-Oxo-3,4-dihydroquinazolin-3-yl)-alkanoic acids ( 8 ) and (4-Oxo-3,4-dihydro-1,2,3-benzotriazin-3-yl)-alkanoic acids ( 6 ) by cyclization of the N-(2-aminobenzoyl)amino acids 5 with HCOOH or HNO₂. 2H-3,1-Benzoxazine-2,4(1H)-diones ( 1 ) reacted with glycine esters to 2 , which were cyclized by HNO₂ to the esters 4 . Ester 4 was hydrolyzed to 6 (X = CH₂). Diones 1 reacted with the most common amino acids (as the ammonium salt of tertiary amine) to amino-alkanoic acids 5 , which were cyclized with orthoformate to 7 or 8 depending on the reaction conditions.     

Enantioselektive α-Alkylierung von Asparagin- und Glutaminsäure über die Dilithium-enolatocarboxylate von 2-[3-Benzoyl-2-(tert-butyl)-1-methyl-5-oxoimidazolidin-4-yl]essigsäure und 3-[3-Benzoyl-2-(tert-butyl)-1-methyl-5-oxoimidazolidin-4-yl]propionsäure

Overall Enantioselective α-Alkylation of Aspartic and Glutamic Acid through Dilithium Enolatocarboxylates of 2- [3-Benzoyl-2-(tert-butyl)-1-methyl-5-oxoimidazolidin-4-yl]acetic and 3-[3-Benzoyl-2-(tert-butyl)-1-methyl-5-oxoimidazolidin-4-yl]propionic Acid, respectively The pure methyl esters 10 of the heterocyclic carboxylic acids specified in the title were prepared in several steps by known methods from aspartic and glutamic acid, with overall yields of ca. 20%. The corresponding heterocyclic acids 11 were doubly deprotonated by LiNEt₂/BuLi or LiN(i-Pr)₂/BuLi to give enolatocarboxylates ( 3 ). The latter were reacted with electrophiles (MeOD, Mel, C₆H₅CH₂Br) to give the crystalline products 14 – 21 diastereoselectively. Hydrolysis of the imidazolidinone ring of three such products gave the corresponding α-branched aspartic and glutamic acids 22 – 24 of known absolute configuration, thus establishing the stereochemical course of the overall enantioselective alkylations.     

A simple and convenient synthesis of 3-[5-(trifluoromethyl)-1,2,3-triazol-4-yl]cinnamic acids from 4-aryl-6-(trifluoromethyl)-2H-pyran-2-ones and sodium azide

4-Aryl-6-(trifluoromethyl)-2H-pyran-2-ones and ethyl 4-aryl-6-(trifluoromethyl)-2-oxo-2H-pyran-3-carboxylates react with sodium azide to produce highly functionalized CF₃-1,2,3-triazoles: 3-[5-(trifluoromethyl)-1,2,3-triazol-4-yl]cinnamic acids and monoethyl esters of [5-(trifluoromethyl)-1,2,3-triazol-4-yl]arylmethylidene malonic acids.     

Formation of ω-(4-oxo-1,4-dihydropyridin-2-yl)alkanamides in the Beckmann rearrangement of spiro-fused cycloalkanone oximes

ω-(4-Oxo-1,4-dihydropyridin-2-yl)alkanamides were obtained from cycloalkanone oximes spirofused to 4-oxo-6-methyl-1,2,3,4-tetrahydropyridine fragment through the α-carbon atom and C², respectively, on heating in polyphosphoric acid. The resulting amides were converted to the corresponding acids and methyl esters. Methylation of 5-(6-methyl-4-oxo-1,4-dihydropyridin-2-yl)pentanamide with diazomethane gave 4-methoxypyridine derivative as the major product and a small amount of N-methyl derivative, 5-(1,6-di-methyl- 4-oxo-1,4-dihydropyridin-2-yl)pentanamide.     

Vanillin esters of aromatic carboxylic acids in the synthesis of benzo[a]acridine and benzo[b][4,7]phenanthroline derivatives

By condensation of vanillin esters of substituted benzoic acids with 2-naphthylamine and 6-quinolylamines and also with cyclic β-diketones (1,3-cyclohexanedione and dimedone) 2-methoxy-4-(11-oxo-7,8,9,10,11,12-hexahydrobenzo[a]acridin-12-yl)-and 2-methoxy-4-(11-oxo-7,8,9,10,11,12-hexahydrobenzo[b][4,7]-phenanthrolin-12-yl)phenyl benzoates were prepared.     

Synthesis of Novel New 2-(2-(4-((3,4-Dihydro-4-oxo-3-aryl quinazolin-2-yl)methyl)piperazin-1-yl)acetoyloxy)-2-phenyl Acetic Acid Esters

Stereoselective diazotization of (S)-2-amino-2-phenyl acetic acid (L-phenyl glycine) (4) with NaNO₂ in 6% H₂SO₄ in a mixture of acetone and water gave optically pure (S)-2-hydroxy-2-phenyl acetic acid (L-mandelic acid) (5). Esterification, gave (S)-2-hydroxy-2-phenyl acetic acid esters (6). The latter was treated with chloroacetyl chloride in the presence of triethylamine (TEA) in dichloromethane (DCM) to yield (S)-2-chloroacetyloxy phenyl acetic acid ester (2). In another sequence, the reaction of 2-(chloromethyl)-3-arylquinazolin-4(3H)-one (9) treated with N-Boc piperazine, followed by deprotection of the Boc group, to obtain 3-aryl-2-((piperazin-1-yl)methyl) quinazolin-4(3H)-one (3). Reaction of 2 with 3 in the presence of K₂CO₃ and KI gave the title compound, 2-(2-(4-((3,4-dihydro-4-oxo-3-arylquinazolin-2-yl)methyl)piperazin-1-yl) acetoyloxy)-2-phenyl acetic acid esters (1). The structures of all the new compounds obtained in the present work are supported by spectral and analytical data.     

Mesogenic 4-[4-(ω-hydroxyalkoxy)phenyl]diazenylcinnamic acids and their 4-cyanophenyl esters

Homologs of a series 4-[4-(ω-hydroxyalkoxy)phenyl]diazenylcinnamic acids (C₂, C₆, C₈, C₉, C₁₀) and their two 4-cyanophenyl esters (C₂, C₆) were synthesized. The substances obtained possess properties of thermotropic nematic liquid crystals. The effect of the terminal hydroxy group of the terminal substituent on their mesomorphous properties was analyzed.     

Reactions of bis(tetrazole)phenylenes. Surprising formation of vinyl compounds from alkyl halides

The reactions of 1,2-bis(tetrazol-5-yl)benzene (1), 1,3-bis(tetrazol-5-yl)benzene (2), 1,4-bis(tetrazol-5-yl)benzene (3), 1,2-(Bu₃SnN₄C)₂C₆H₄ (4), 1,3-(Bu₃SnN₄C)₂C₆H₄ (5) and 1,4-(Bu₃SnN₄C)₂C₆H₄ (6) with 1,2-dibromoethane were carried out by two different methods in order to synthesise pendant alkyl halide derivatives of the parent bis-tetrazoles. This lead to the formation of several alkyl halide derivatives, substituted at either N1 or N2 on the tetrazole ring, as well as the surprising formation of several vinyl derivatives. The crystal structures of both 1,2-[(2-vinyl)tetrazol-5-yl)]benzene (1-N,2-N′) (1b) and 1,3-bis[(2-bromoethyl)tetrazol-5-yl]benzene (2-N,2-N′) (5d) are discussed.     

Enantioseparation of Some New 1-(2-Naphthyl)-1-ethanol Ester Derivatives by HPLC on Chiralcel OD

The direct enantiomeric resolution of racemic 2-(1H-imidazole-1-yl)-1-naphthalene-2-yl)ethanol esters, 1-(naphthalene-2-yl)ethanol esters, and 1-(1-hydroxynaphthalene-2-yl)-2-(1H-imidazole-1-yl)ethanol on silica-based cellulose tris(3,5-dimethylphenylcarbamate) (Chiralcel OD) column is described. The separations were performed using mobile phases which consist of alcohol (methanol, ethanol or 2-propanol)/n-hexane in various proportions. The effect of structural features of the solutes along with the nature and concentration of alcohol in the mobile phase on the discrimination between the enantiomers was examined for different mobile phase compositions. The results suggest that not only the structure and concentration of alcohol in the mobile phase, but also the subtle structural differences in racemates can have a pronounced effect on enantiomeric separation and retention. Baseline separations were obtained for 2-(1H-imidazole-1-yl)-1-naphthalene-2-yl)ethanol esters carrying imidazole ring in addition to ester functional group in their structures. The α values of the resolved enantiomers of 2-(1H-imidazole-1-yl)-1-naphthalene-2-yl)ethanol esters were in the range of 1.49–1.62 while the R _s values varied from 4.20 to 6.75 when methanol/n-hexane (70:30 v/v) was used as mobile phase.

     

Synthesis and mesomorphic properties oftrans-[1,4-bis(5-R-pyrimidin-2-yl]-cyclohexanes and 1,2-bis-(5-R-pyrimidin-2-yl)ethanes

New trans-bis(5-R-pyrimidin-2-yl)-1,4-cyclohexanes and-1,2-ethanes (R=C₇H₁₅, C₆H₄OR¹, where R¹=H, COCH₃, C₄H₉, C₅H₁₁, C₈H₁₇) have been synthesized. Only nematic mesophases are found from a study of their mesomorphic properties, except for bis[5-(4-octyloxyphenyl)- and-(4-acetoxyphenyl)pyrimidin-2-yl)-cyclohexanes, which also exhibit smectic properties.Novosibirsk Institute of Organic Chemistry of the Siberian Division of the Russian Academy of Sciences, Novosibirsk 630090, Russia; e-mail: benzol@nioch.nsc.ru. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 355–360, March, 1999.     

Allylstannation: VII. Preparation of carboxylic acid 1-alkene-4-yl and 1-alkyne-4-yl esters by transalkoxylation of 4-n-dibutylchlorostannoxy-1-alkenes and 4-n-dibutylchlorostannoxy-1-alkynes with acyl chlorides

Carboxylic acid 1-alkene-4-yl and 1-alkyne-4-yl, esters (RCH(CH₂CHCH₂)OCOR′ ad RCH(CH₂CCH)OCOR′, R = R′ or R ≠ R′ = alkyl or alkenyl group) can be readily prepared in high yields by transalkoxylation reactions between 4-n-dibutylchlorostannoxy-1-alkenes or 4-n-dibutylchlorostannoxy-1-alkynes with acyl chlorides. This represents a general route for preparation of esters containing allyl or propargyl groups.     

Crystal structure and luminiscent properties of 2,2-difluoro-4-(9H-hluorene-2-YL)-6-methyl-1,3,2-dioxaborine

The crystal structure of 2,2-difluoro-4-(9H-fluorene-2-yl)-6-methyl-1,3,2-dioxaborine (C₁₃H₉COCH × COCH₃BF₂) (1) is determined. The structural and spectral luminescent characteristics of 1 are compared to those of its electron analogue: 2,2-difluoro-4-(4-phenylphenyl)-6-methyl-1,3,2-dioxaborine (C₆H₅C₆H₄ × COCHCOCH₃BF₂).     

Über die Dicyanierung der 1,4-Diaminoanthrachinone und die Reaktivität der 1,4-Diamino-9,10-dihydroanthracen-2,3-dicarbonitrile gegenüber nucleophilen Reagenzien 3. Mitteilung über Arylierungen und Heterocyclisierungen von Anthrachinonsystemen

The Dicyanation of 1,4-Diaminoanthraquinones and the Reactivity of 1,4-Diamino-9,10-dioxo-9,10-dihydroanthracene-2,3-dicarbonitriles towards Nucleophilic Reagents The reaction of 1-amino-9, 10-dioxo-4-phenylamino-9,10-dihydroanthracene-2-sulfonic acid ( 1 , R?C₆H₅) with cyanide in water yields a mixture of 1-amino-9,10-dioxo-4-phenylamino-9,10-dihydroanthracene-2-carbonitrile ( 3 , R ? C₆H₅) and 1-amino-4-(phenylamino)anthraquinone ( 4 , R ? C₆H₅) under the usual reaction conditions (Scheme 1). In dimethylsulfoxide, however, a second cyano group is introduced, and 1-amino-9,10-dioxo-4-phenylamino-9,10-dihydroanthracene-2,3-dicarbonitrile (7) is formed (Scheme 2). The cyano groups are very reactive towards nucleophiles. The cyano group in 2-position can be substituted by hydroxide and aliphatic amines (Schemes 5 and 6). The cyano group in 3-position can be eliminated by aliphatic amines and hydrazine (Scheme 7). Nucleophilic attack at the cyano C-atom of the 2-cyano group by suitable reagents leads to ring formation, yielding e.g. 2-(Δ²-1, 3-oxazolin-2-yl)-, 2-(benz[d]imidazol-2-yl)- and 2-(1H-tetrazol-5-yl)anthraquinones (Schemes 8 and 10).     

New monomers for fullerene-containing polymers

By reaction of 2-(acryloyloxyethyl) and (undecen-10-en-1-yl) methylmalonates with fullerene C₆₀ in the system toluene-CBr₄-DBU, and also by reaction of 2-(2,2-dichloroacetoxy)ethyl acrylate with C₆₀ in the system toluene-DBU the corresponding products of fullerene monocyclopropanation were synthesized.