bluuebunny/crossref_metadata_2025 huggingface dataset:
A stereoselective three‐component reaction: One‐pot synthesis ofcis‐isoquinolonic acids catalyzed by silica sulfuric acid under mild and heterogeneous conditions
Authors: Azizian Javad , Mohammadi Ali A. , Soleimani Ebrahim , Karimi Ali R. , Mohammadizadeh Mohammad R.
Published: March 2009

magnified image

A mild and stereoselective three‐component one‐step synthesis ofcis‐isoquinolonic acid using silica sulfuric acid as a heterogeneous catalyst from an aldehyde, amine and homophthalic anhydride in acetonitrile is described. This new method produces pure products in high yields (81‐91%).
Reaction of 3‐aminoquinoline‐2,4‐diones with isocyanates. Synthesis of novel 3‐(3′‐alkyl/arylureido)quinoline‐2,4‐diones and their cyclic carbinolamide isomers
Authors: Klásek Antonín , Hoza Ignác , Lyčka Antonín , Holčapek Michal
Published: March 2009

magnified image

3‐Alkyl/aryl‐3‐amino‐1H,3H‐quinoline‐2,4‐diones react with alkyl/aryl isocyanates to give novel 3‐alkyl/aryl‐3‐ureido‐1H,3H‐quinoline‐2,4‐diones or 3a‐alkyl/aryl‐9b‐hydroxy‐3,3a,5,9b‐tetrahydro‐1H‐imidazo[4,5‐c]quinoline‐2,4‐diones. In some cases, a mixture of both products was obtained and separated by fractional crystallization. All compounds were characterized by their 1H, 13C, ir and ms data and some of them also by 15N nmr data.
Intermolecular aza‐wittig reaction: One‐step synthesis of pyrazolo[1,5‐a]pyrimidine and imidazo[1,2‐b]pyrazole derivatives
Authors: Barsy Magda A. , El‐Rady Eman A.
Published: March 2009

magnified image

Pyrazolo[1,5‐a]pyrimidine and imidazo[1,2‐b]pyrazole derivatives were synthesized via intermolecular aza‐Wittig reaction of 5‐(triphenylphosphoranylideneamino)‐3‐phenylpyrazole 3 derived from 5‐amino‐3‐phenylpyrazole with some selected α‐chloroketones.
Reactivity of 3‐amino‐3H‐quinazolin‐4‐one derivatives towards some electrophilic and nucleophilic reagents and using of the products in the building of some interesting heterocycles as anticancer agent
Authors: Abdel‐Rahman Taha.M.
Published: March 2009

magnified image

The chemical reactivity of N‐[1‐(3‐amino‐6,8‐dibromo‐4‐oxo‐3,4‐dihydro‐quinazolin‐2‐yl)‐2‐(2‐chlorophenyl)‐vinyl]benzamide (3) towards electrophilic and nucleophilic reagents have been reported. Structures of the products 3‐24 have been confirmed by elemental analysis and spectral data (IR, 1H‐NMR, 13C and MS). The bioassay indicates that some of the prepared compounds have a good selective anticancer activity.
Facile preparation and the crystal structure of N, N′‐dialkyl‐2,6‐pyridinedimethanaminium halide
Authors: Kobayashi Tohru , Yaita Tsuyoshi , Sugo Yumi , Suda Hiroki , Suzuki Shinji , Fujii Yuki , Nakano Yoshiharu
Published: March 2009

magnified image

A facile preparation and the crystal structures of N, N′‐dialkyl‐2,6‐ pyridinedimethanaminium halides were described. Direct substitution reactions were convenient to prepare specifically secondary diamines using 2,6‐bis(chloromethyl)‐ pyridine and 10 equivalents molar of primary alkylamines. Hydrogen halide salts were obtained in good yields and the crystal structures of three N, N′‐dialkyl‐2,6‐pyridinedimethanaminium salts were determined by the X‐ray diffraction method. A cancroid structure around the pyridine ring was observed commonly in the three salts. Acidity constants of the three salts were determined. Since the pKa values of the salts were slightly smaller than those of several common triamines previously reported, the acidities did not correlate with the cancroid structure directly. This is probably due to electrostatic interaction of the two protonated amino groups, furthermore the central pyridine nitrogen was not protonated in all the ligands.
Chloroformamidinium salts: Efficient reagents for preparation of 2‐aminobenzoimidazole, 2‐aminobenzoxazole, and 2‐aminobenzothiazole derivatives
Authors: El‐Faham Ayman , Chebbo Mohamed , Abdul‐Ghani Mohamed , Younes Ghassan
Published: March 2009

magnified image

A Reaction involving chloroformamidinium salts (TCFH 1a, BTCFH 1b, DmCFH 1c, DmPCFH 1d, BPCFH 1e) and 2‐aminophenol 9a, benzene‐1,2‐diamine 9b, and 2‐aminothiophenol 9c afforded 2‐aminobenzoxazole 13, 2‐aminobenzoimidazole 14, and 2‐aminobenzothiazole 15 derivatives, respectively as major products, due to the in situ heterocyclization with dimethylamine acting as the better leaving group. Attempts for preparation of 13‐15 from the reaction of N,N‐dimethyl carbomyl chloride 16 with 2‐aminophenol 9a, benzene‐1,2‐diamine 9b, and 2‐aminothiophenol 9c were unsuccessful, and gave the unexpected products benzoxazol‐2‐ol 18a, benzoimidazol‐2‐one 18b, and S‐(2‐amino‐phenyl) N,N‐dimethylthiocarbamate 19 respectively. On the other hand reaction of chloroformamidinium salts 1a‐e with 3‐benzyl‐2‐hydrazinoquinoxaline 3 and 1‐hydrazinophthalazine hydrochloride 4 in the presence of triethylamine as a base, afforded the [1,2,4]triazolo derivatives 6 and 7 respectively in good yield and purity. These triazole derivatives were formed due to the strong tendency towards heterocyclization and substitution of dimethylamine group as a better leaving group.
Cyclocondensation reactions of heterocyclic carbonyl compounds XI . Synthesis and study of cyclocondensation reactions of some 3‐substituted‐5‐(2‐aminobenzyl)‐1H‐[1,2,4]triazine‐6‐ones
Authors: Guckýa Tomáš , Slouka Jan , Fryšová Iveta , Maloň Michal
Published: March 2009

magnified image

A series of 2‐substituted‐4‐(2‐nitrobenzylidene)‐4,5‐dihydrooxazol‐5‐ones (2a‐2i) was prepared by the Erlenmeyer's synthesis of 2‐nitrobenzaldehyde with acylglycines (1a‐1i) and the series of corresponding aminoderivatives (3b‐3d and 3g‐3i) was synthetised by catalytic hydrogenation of (2b‐2d and 3g‐3i). Hydrazinolysis of azlactones (2) and (3) gave hydrazides (4) and (5). The hydrazides (5) were also obtained by catalytic hydrogenation of corresponding nitroderivatives (4). The cyclization reaction of hydrazides (4) or (5) proceeded to 3,5‐disubstituted‐1,6‐dihydro‐[1,2,4]triazine‐6‐ones (6) or (7). Aminoderivatives (7) were also obtained by reduction of nitro group of compounds (6). The aminoderivatives (7) were then cyclized to 3‐substituted‐1,5‐dihydro‐[1,2,4]triazino[6,5‐b]quinolines (9), resp. its tautomers (10).
Furan ring opening ‐ indole ring closure: Synthesis of furo[2′,3′:3,4]‐cyclohepta[1,2‐b]indolium chlorides
Authors: Butin Alexander V. , Smirnov Sergey K. , Stroganova Tatyana A.
Published: March 2009

magnified image

A new synthetic approach to furo[2′,3′:3,4]cyclohepta[1,2‐b]indolium chlorides is elaborated starting from 2‐acetylaminoaryldifurylmethanes or 2‐aminoaryldifurylmethanes under treatment with methanolic HCl solution. The reaction proceeds in three steps: recyclization, intramolecular cyclization, and disproportionation. In this case the furan ring takes part in building up both pyrrole and seven‐membered rings. The same salts can be obtained directly from 2‐acetylaminobenzaldehydes and 2‐methylfuran under similar conditions without isolation of corresponding 2‐acetylaminoaryldifurylmethanes.
Ring expansion of isopropenyldihydrofuran derivatives
Authors: Yamaguchi Seiji , Tsuchida Nao , Umeda Kayoko , Yokoyama Hajime , Miyazawa Masahiro , Hirai Yoshiro
Published: March 2009

magnified image

Lactonization of 2‐(hydroxymethyl)‐5‐isopropenyl‐4,5‐dihydrofuran‐3‐carboxylic acids 1a,b,c with dicyclohexylcarbodiimide gave the corresponding furano‐lactones, 5‐isopropenyl‐5,6‐dihydro‐1(3H)‐furo[3,4‐b]furanone 2a,b,c, which were readily converted to the corresponding oxepino‐lactones, 6‐methyl‐5,8‐dihydro‐1(3H)‐furo[3,4‐b]oxepinone 3a,b,c by respective thermal ring expansions.
Synthesis, properties and X‐ray structure of 5‐azido‐2‐methoxy‐1,3‐xylyl‐18‐crown‐5
Authors: Yonekawa Sayuri , Goodpaster Aaron M. , Abel Benjamin A. , Paulin Rodney G. , Sexton Charles W. , Poole James S. , Storhoff Bruce N. , Fanwick Phillip E.
Published: March 2009

magnified image

5‐Azido‐2‐methoxy‐1,3‐xylyl‐18‐crown‐5 has been prepared by reacting p‐toluenesulfonyl azide with the carbanion generated from the reaction of 5‐bromo‐2‐methoxy‐1,3‐xylyl‐18‐crown‐5 with n‐butyl lithium. The asymmetric N3 stretch of this product has been observed as a single band at 2110 cm−1 in dichloromethane solution. Addition of solid NaSCN, KSCN and CsSCN shifts this band to 2115, 2113 and 2112 cm−1, respectively. Computational studies of this azide at the B3LYP‐6‐31G* level in the presence and absence of Na+ predicted these bands to be at 2173 cm−1 and 2184 cm−1. For the salt‐containing solutions, additional bands were observed at 2066 cm−1, 2056 cm−1 and 2055 cm−1, respectively, which are in the range expected for CN stretches. The X‐ray structure of this azide has been determined. The terminal and internal NN bond lengths were found to be 1.127(2) and 1.245(2) Δ, respectively, which is the usual pattern for aromatic azides. The crown ether is looped over the face of the aromatic ring resulting in an angle of 38.94° between the plane defined by the aromatic ring and that defined by the five ring oxygen atoms. In addition, the CH3 group is rotated out of the plane of the phenyl ring with C1‐C18‐O181‐C182 and C17‐C18‐O181‐C182 dihedral angles of 93.81(14)° and ‐90.54(14)°, respectively.
A study on the ability of 2,5‐dihydro‐ and 2,3,4,5‐tetrahydro‐1h‐phosphole oxides, as well as 7‐phosphanorbornene 7‐oxide derivatives to undergo uv light‐mediated fragmentation‐related phosphinylation of methanol
Authors: Keglevich Gyöurgy , Kovács János , Szelke Helga , Köurtvéalyesi Tamás
Published: March 2009

magnified image

Reactivity of the title P‐heterocycles (1‐14) in the photoinduced fragmentation‐related phosphinylation of methanol was found to be influenced by the extent of ring strain and the UV absorption at 254 nm. The 7‐phosphanorbornene oxides (7‐14) are universal precursors due to their ring strain, no matter if they are UV‐active or not at 254 nm. The easily available 2,5‐dihydro‐1H‐phosphole oxides can be applied only in case of 1‐phenyl substitution that enhances the absorption at 254 nm. The ring strain of representative P‐heterocycles (5‐8) was evaluated by HF/6‐31G* and B3LYP/6‐31+G* calculations. UV spectra of compounds 5‐8 were interpreted by ZINDO/S and MNDO‐d calculations. The new precursors (11‐14) made possible the extension of the phosphinylations.
Novel synthesis of 2H‐3,1‐benzoxazine derivatives
Authors: Li Jia‐Rong , Ma Shu‐Ling , Sun Yong‐Jiang , Wei Xiao‐Jie , Zhou Zhi‐Ming
Published: March 2009

magnified image

On heating of the 2‐amino‐5‐nitrobenzonitrile 1 with cyclohexanone 2a in the presence of catalyst, the novel compound 6‐nitrospiro[3,1‐benzoxazine‐2,1′‐cyclohexan]‐4(1H)‐imine 5a was formed. Also, reaction of 1 with cyclopentanone 2b or cycloheptanone 2c afforded 5b or 5c respectively. All new compounds were identified by 1H NMR, 13C NMR, IR, MS spectra and elemental analysis. The crystal structure of product 5a was determined by crystal X‐ray diffraction. And the mechanism for these reactions is proposed.
1,3‐Dihydro‐2H‐imidazo[4,5‐c]pyridin‐2‐one
Authors: Holt Jarle , Bakke Jan M. , Fiksdahl Anne
Published: March 2009

magnified image

A facile acid catalysed cyclisation method for the preparation of the cyclic urea 2H‐imidazo[4,5‐c]pyridin‐2‐one (2) in > 95 % yield is reported. The biologically active compound 2 can be obtained by heating (3‐amino‐4‐pyridinyl)‐carbamic acid methyl, ethyl or tert‐butyl esters (1a‐c) in sulfuric acid (0.1 %) or in aqueous HBF4 (3.5 equivalents) for 10 min. ‐ 3 hrs at 90 °C. The corresponding microwave‐promoted (MW) reactions afforded the pure product 2 within few minutes. The 6‐butylamino‐substituted analogue (2a) was correspondingly obtained by MW irradiation in 99 % yield by cyclisation of 2‐(butylamino)‐5‐amino‐4‐pyridylcarbamic acid isopropyl ester (1d). Quantitative precipitation of product 2 was obtained by pH adjustment. The process represents a solvent‐free, “green” method for the preparation of 2.
One pot synthesis of diarylpyrido[3,2‐c]coumarins
Authors: Pandya Shashi U. , Pandya Urvish R. , Hirani Bhanu R. , Brahmbhatt Dinker I.
Published: March 2009

magnified image

Various diarylpyrido[3,2‐c]coumarins 3a‐l have been synthesized in one step by reacting 4‐hydroxy coumarins 1a‐d with α,β‐unsaturated ketones 2a‐c in the presence of ammonium acetate and acetic acid under Kroehnke's reaction conditions.
The dipolar route to naphtho[2,1‐c]isoxazoles from the baylis‐hillman adducts of 2‐alkynylbenzaldehydes
Authors: Ji Sang‐Hoon , Hong Wan Pyo , Ko Seung Ho , Lee Kee‐Jung
Published: March 2009

magnified image

A new synthesis of 4‐carbomethoxynaphtho[2,1‐c]isoxazoles 4a‐d from methyl 3‐(alkynylphenyl)‐2‐nitromethyl‐2‐propenoates 2a‐d by the intramolecular nitrile oxide cycloaddition is described. The latter are readily obtained from 2‐alkynylbenzaldehydes through the Baylis‐Hillman adduct acetates 1a‐d followed by nucleophilic substitution of nitrite anion.
Transformation of a spirobarbituric acid via aminobarbituric acid‐hydantoin rearrangement
Authors: Ambrożak Agnieszka , Güutschow Michael
Published: March 2009

magnified image

A successful application of the aminobarbituric acid‐hydantoin rearrangement to produce a bicyclic carbamoylhydantoin from an intermediate spirobarbituric acid is reported. 7a‐Phenylcarbamoyl‐tetrahydro‐1H‐pyrrolo[1,2‐c]imidazole‐1,3(2H)‐dione (8) was obtained in a one‐pot multistep reaction of 1‐acetyl‐2,2‐bis(ethoxycarbonyl)pyrrolidine (5) and phenylurea in the presence of sodium ethoxide. Under less severe conditions, 5 and phenylurea were reacted to afford 1‐acetyl‐7‐phenyl‐triaza[4,5]decane‐6,8,10‐trione (6). The structural elucidation of the bicyclic hydantoin 8 and the spirobarbituric acid 6 was based on relevant nmr signals in accordance with those of reference compounds, i.e. monocyclic hydantoins 4a,b and acetamidobarbituric acids 2a‐c. The latter compounds were newly prepared from diethyl acetamidomalonates 1 and phenylurea.
An efficient one‐pot synthesis of 6‐aryl‐5‐cyano‐2‐thiopyrimidinone derivatives and their piperidinium ionic forms, x‐ray crystal structures
Authors: Balalaie Saeed , Bararjanian Morteza , Rominger Frank
Published: March 2009

magnified image

Three‐component condensation of benzaldehyde derivatives, alkyl cyanoacetates and thiourea in the presence of piperidine in reflux condition provides a direct route to piperidinium 6‐aryl‐5‐cyano 2‐thiopyrimidonate salts in good yields. These reactions were also carried out under microwave irradiation. The yields of products under the microwave condition were better as compared to the reflux media. The acidification of these ionic forms resulted in the formation of 6‐aryl‐5‐cyano‐2‐thiopyrimidone derivatives. The X‐ray structures of the ionic forms (4, 5, and 7) show that there are anionic thiopyrimidinone skeletons hydrogen bridged with piperidinium cations.
A facile synthesis of pyrazolo[3,4‐D]pyridazines Via the 1,3‐dipolar cycloaddition of 3‐arylsydnones. Synthesis and computational studies of 1‐aryl‐4,5‐dihydro‐1H‐pyrazolo[3,4‐D]pyridazine‐3,6‐diones and their 3,6‐dichloro derivatives.
Authors: Sanyal R. , Badami Bharati V.
Published: March 2009

magnified image

The synthetic utility of 1,3‐dipolar cycloaddition of DMAD to sydnones has been exploited in the preparation of new 1‐aryl‐4,5‐dihydro‐1H‐pyrazolo[3,4‐d]pyridazine‐3,6‐diones 7a‐j and their aromatic 3,6‐dichloro analogues 8a‐j. The lactam‐lactim tautomerism of compound 7a has been studied by the semi emperical (PM3) and ab initio methods.
Ring transformation of 1,5‐diazabicyclo[3.1.0]hexanes under the action of arylketenes
Authors: Shevtsov Alexander V. , Kuznetsov Vladimir V. , Kislukhin Alexander A. , Petukhova Vera Yu. , Strelenko Yu. A. , Makhova Nina N. , Lyssenko Konstantin A.
Published: March 2009

magnified image

The reactions of 1,5‐diazabicyclo[3.1.0]hexanes 8 with arylketenes 1 have been studied in different conditions. The 1‐(arylacethyl)pyrazolidines 11 were obtained at −30 °C in ether and at 20 °C in benzene instead of the expected bicyclic systems 1,5‐diazabicyclo[3.2.1]octan‐6‐one 9 and 3‐aryl‐1,5‐diazabicyclo[3.3.0]octane‐2‐one 10. The synthesis of two representatives of bicycles 10 (10a,b) proceeded in the reaction of unsubstituted 1,5‐diazabicycle[3.1.0]hexane 8a, accordingly, with diphenylketene 1a in benzene at 20 °C and with 4‐chlorophenylketene 1b in toluene at 60‐110 °C. Mechanisms of the studied transformations were offered.
Synthesis and chemical transformation of fused tetrazoles derived from 2‐bromomethyl‐ and 2‐iodomethyl‐3,5,6,7‐tetrahydro‐4(2H)‐benzofuranones
Authors: Mphahlele Malose J. , Moekwa Thwanthwadi B.
Published: March 2009

magnified image

The 2‐bromomethyl‐3,5,6,7‐tetrahydrobenzofuranones 1a‐d were subjected to triazidochlorosilanesodium azide‐mediated Schmidt rearrangement to afford the corresponding tetrazolofuroazepine derivatives 2a‐d via methylene shift. Under similar reaction conditions, the 2‐iodomethyl‐3,5,6,7‐tetrahydrobenzofuranones 1e‐h afford mixtures of the corresponding tetrazolofuroazepines 2e‐h and the 4‐azido‐2‐iodomethyl‐2,3‐dihydrobenzofuran derivatives 3a‐c. A mechanism is proposed to account for the divergence in the reactivity of these 2‐halogenomethyltetrahydrobenzofuranones (X = Br versus I). In turn, the 2‐halogenomethyltetrazolofuroazepines 2a,b,d‐h and the 4‐azido‐2‐iodomethyl‐2,3‐dihydrobenzofurans 3a,b underwent nucleophilic substitution with triethyl phosphite and dehydrohalogenation using DBU in refluxing toluene to give the corresponding tetrazolofuroazepines 4a‐d and 5a‐c and benzofurans 6a,b.
Efficient synthesis of 3‐arylaminopyrroline‐2‐ones by the tandem reaction of anilines and β,γ‐unsaturated α‐ketoesters
Authors: Wu Yan‐Chao , Liu Li , Wang Dong , Chen Yong‐Jun
Published: March 2009

magnified image

A concise and efficient synthetic approach to 3‐arylaminopyrroline‐2‐ones from anilines and β,γ‐unsaturated α‐ketoesters in boiling dichloromethane has been developed. This protocol possesses many advantages such as short reaction time, high isolated yields, and expanding substrate scopes. According to the isolated intermediates and controlled reactions, the reaction was tentatively proposed to involve the Michael addition/condensation and subsequent intramolecular cyclization. The structures of the title compounds were unambiguously confirmed by various spectral data such as X‐ray crystallographic analysis.
New TRANS/CIS tetrahydroisoquinolines. 3. [1,3]‐oxazolo‐[3,2‐B]‐tetrahydroisoquinolinones having an angular aryl substituent
Authors: Christov P. P. , Kozekov I. D. , Palamareva M. D.
Published: March 2009

magnified image

The parent compound 5‐oxo‐10a‐phenyl‐2,3,10,10a‐tetrahydro‐5H‐[1,3]‐oxazolo‐[3,2‐b]‐isoquinoline‐10‐carboxylic acid (5) was prepared in large scale and a good yield by reaction between homophthalic anhydride (3) and 4,5‐dihydro‐2‐phenyl‐1,3‐oxazole (4). Thus, the closure of the isoquinoline ring and fusion of the 1,3‐oxazol ring occur in one step. Trans configuration was assumed for the product. The parent acid 5 was converted in four steps to the target aminomethyl derivatives 9a‐1. The latter contain four features that make them interesting from pharmaceutical point of view.
Synthesis and biological activities of cis and trans 5‐amino‐3‐[(6‐chloro‐3‐pyridyl)methyl]amino‐1‐(5,5‐dimethyl‐2‐oxo‐4‐substitutedphenyl‐1,3,2‐dioxaphosphinan‐2‐yl)‐4‐cyano(ethoxycarbonyl)‐1H‐pyrazoles
Authors: Luo Zai‐Gang , Shi De‐Qing
Published: March 2009

magnified image

A series of novel title compounds have been designed and synthesized by a multi‐step reaction, the stereochemistry of the reaction was investigated, the structures of all compounds prepared have been confirmed by 1H NMR, IR, EI‐MS spectroscopy and elemental analysis. The crystal structures of cis 6b and trans 6b were determined by single crystal X‐ray diffraction. The results of preliminary bioassay indicate that some compounds possess a certain extent inhibition effect against aphides at the concentration of 250 ppm.
Convenient synthesis of some 2‐substituted 4(3H)‐quinazolinone derivatives
Authors: Philipova I. , Dobrikov G. , Krumova K. , Kaneti J.
Published: March 2009

magnified image

A series of 2‐substituted‐4(3H)‐quinazolinones 13‐20 has been synthesized in good yields using the reaction of double lithiated 2‐methylquinazolinone‐4 with a variety of aromatic aldehydes. They have been easily transformed in high yields into the corresponding 2‐substituted conjugated derivatives 21‐28 bearing terminal aryl groups by F3CCOOH mediated dehydration.
Stereocontrolled synthesis of tricyclic fused oxazolidinone as antibacterial agent
Authors: Cui Yingjie , Dang Yaxian , Yang Yushe , Ji Ruyun
Published: March 2009

magnified image

Tricyclic fused oxazolidinone 3a and 3b have been synthesized as antibacterial agents in 12 and 11 steps respectively. The key intermediates 10a and 10b have been developed via opening of epoxide 9a and 9b and cyclization by the resulting oxygen anion attack.
Chemistry of quinuclidines as nitrogen bicyclic bridged‐ring structures
Authors: Hamama Wafaa S. , El‐Magid Osama. M. Abd , Zoorob Hanafi H.
Published: March 2009

This review summarises the structure, basicity, asymmetric organocatalysis, synthesis and reactions of quinuclidines. Quinuclidines are bicyclic saturated pyridin‐containing compounds with rigid structures and a ring‐juncture nitrogen atom. This review covers the period from 1984–2005.
Highly diastereoselactive synthesis of chimeras of proline and glutamate
Authors: Kudryavtsev Konstantin V. , Tsentalovich Mikhail Yu. , Yegorov Anton S. , Kolychev Eugene L.
Published: March 2009

magnified image

Azomethine ylides have been generated from aromatic aldimines of α‐amino acid methyl esters under treatment with LiBr/Et3N and trapped with tert‐butyl acrylate yielding racemic orthogonally protected cis‐5‐arylpyrrolidine‐2,4‐dicarboxylates regio‐ and stereo‐selectively in high yields. Subsequent N‐methylation and deprotection of 4‐carboxylic group of cycloaddition products led to novel prolineglutamate cis‐chimeras with substituents at 2 and 5 positions of pyrrolidine scaffold.
A highly regioselective synthesis of 1‐n‐methyl‐spiro‐[2,3′“]‐oxindole‐spiro‐[3,2”]indane‐1“, 3”‐dione‐4‐arylpyrrolidines through 1,3‐dipolar cycloaddition protocol
Authors: Babu A. R. Suresh , Raghunathan R. , Gayatri G. , Sastry G. Narahari
Published: March 2009

magnified image

2‐Arylidene‐1,3‐indanediones undergo a regioselective 1,3‐dipolar cycloaddition reaction with the azomethine ylide derived from isatin and sarcosine by decarboxylative route affording a series of 1‐N‐methyl — spiro[2.3′“]oxindole‐spiro[3.2”]indane‐1“,3”‐diones‐4‐aryl pyrrolidines. The structures were established by spectroscopic techniques as well as single crystal X‐ray analysis. Density functional theory at B3L YP/6‐31G* and the semi empirical AM1 calculations were employed to rationalize the observed results. The experimental regioselectivity of 1,3‐dipolar cycloadditions could be corroborated nicely with the computed Fukui frontier orbital energies and reaction energies.
Synthesis of new flat polyheterocyclic systems potential DNA intercalating agents diazines part 47
Authors: Audoux Jérôme , Achelle Sylvain , Turck Alain , Marsais Francis , Plé Nelly
Published: March 2009

magnified image

Using a regioselective metallation in connection with Stille cross‐coupling reaction, we report here an original synthetic route to obtain in few steps various flat tetra‐ or pentaheterocyclic compounds which could be potential intercalating DNA agents.
Alpha vinylation of haloquinoline‐5,8‐diones with methyl acrylate and methyl vinyl ketone under baylis‐hillman reaction conditions
Authors: Song Hyoung Seok , Song Young Seok , Lee Kee‐Jung
Published: March 2009

magnified image

A synthesis of mono‐ and di‐vinylquinolinediones based on substitution of the halogens in 6,7‐dihaloquinoline‐5,8‐diones by DABCO‐assisted enolate ion is described. Divinylquinolines undergo 6π‐electrocyclization by thermally to give the benzo[g]quinoline derivatives.
Regioselective one pot synthesis of 2‐alkyl/aryl‐4h‐benzo[1,4] thiazine‐3‐one via microwave irradiation
Authors: Kamila Sukanta , Koh Benjamin , Khan Omair , Zhang Hongming , Biehl Edward R.
Published: March 2009

magnified image

A series of 2‐alkyl/aryl‐4H‐benzo[1,4]thiazine‐3‐ones have been synthesized by microwave irradiation of ethyl‐2‐bromo‐2‐alkyl/aryl acetate and 2‐amino thiophenol in the presence of 1,8‐diazabicyclo‐[5.4.0] undec‐7‐ene and N‐methylpiperidine. All compounds were characterized by 1H NMR, 13C NMR and elemental analyses, and by X‐ray crystallography in the case of 2‐methyl‐4H‐benzo[1,4]thiazin‐3‐one.
Some imines and azo compounds containing furoxan ring synthesized from methylisoeugenol
Authors: Dinh Nguyen Huu , Ly Ngo Thi , Van Hoan Pham
Published: March 2009

magnified image

Some imines and azo compounds containing furoxan and benzene rings have been prepared starting from methylisoeugenol. The structure of reported compounds has been confirmed by elemental analysis, ms, uv, ir, and nmr spectroscopy. It is shown that, on treatment with Na2S2O4, the nitro group on the benzene ring was reduced to an amino group, but the N←O group of furoxan ring was not. The 1H‐ and 13C nmr signals are assigned based on their spin‐spin splitting patterns, in some cases, NOESY and HMBC spectra are used. The NOESY spectra indicate that the reported imines have E‐configuration. Among 8 tested compounds, there are 5 compounds that exhibit anti‐microbial activity toward Gr+ S. aureus at concentration 12.5μg/mL.
Synthesis, complexation and antifungal, antibacterial activity studies of a new macrocyclic schiff base
Authors: Ugras H. Ibrahim , Basaran Ismet , Kilic Turgut , Cakir Umit
Published: March 2009

magnified image

A new macrocyclic ligand, L was synthesized using the high dilution condition with condensation of triethylene glycol diamine and terephtalaldehyde in ethanol. The obtained product, L was identified by FT‐IR, 1H‐NMR, 13C‐NMR and Mass spectroscopy. The extraction equilibrium constants were estimated using dichloromethane/water membranes transfer with ICP‐AES and AES spectroscopy. Biological studies of this compound was determinated with disc diffusion method. The biological activity results showed that the synthesized ligand L has high activity against the studied microorganisms and high complexation ability against the Fe2+ cation.
First synthesis of furo[3,4‐c]coumarins
Authors: Brahmbhatt Dinker I. , Gajera Jitendra M. , Patel Chirag N. , Pandya Vishwesh P. , Pandya Urvish R.
Published: March 2009

magnified image

Various 1,3‐dimethyl and 1‐methyl‐3‐phenylfuro[3,4‐c]coumarins (5a‐h and 6a‐h) have been synthesized by demethylation cyclization of the respective 3‐aryl‐4‐ethoxycarbonyl furans (3a‐h and 4a‐h). These ethoxycarbonyl furans were prepared by reacting appropriate 1‐aryl‐2‐nitro‐prop‐1‐ene (1a‐h) with ethyl acetoacetate or ethyl benzoylacetate under Nef reaction condition.
Chemical properties of pyrimidoquinoxaline 6‐oxides
Authors: García Ma. Beatriz , Orelli Liliana R. , Perillo Isabel A.
Published: March 2009

magnified image

The reactivity of some representative 5‐arylpyrimidoquinoxaline 6‐oxides 1 was investigated. Reduction with sodium borohydride afforded the corresponding N‐deoxy compounds 2. Reaction with methyl iodide in excess led selectively to N‐methyl derivatives 3. The preference for N vs. O‐alkylation is analyzed considering electronic effects. Alkaline hydrolysis of compounds 1 involved initial nucleophilic attack to the amidine carbon (C4a), and subsequent regioselective ring opening leading to 4‐(3‐aminopropyl)‐2‐aryl‐quinoxaline‐3‐one 1‐oxides 4. The regioselectivity observed in alkaline hydrolysis is also discussed.
Microwave‐accelerated synthesis of benzyl 3,5‐dimethyl‐pyrrole‐2‐carboxylate
Authors: Regourd Jasmine , Comeau Ian M. , Beshara Cory S. , Thompson Alison
Published: March 2009

magnified image

Benzyl 3,5‐dimethyl‐pyrrole‐2‐carboxylate, a very useful pyrrole in porphyrin and dipyrromethene synthesis, can be synthesized via the Knorr‐type reaction, but in low yield. Alternative routes to benzyl 3,5‐dimethyl‐pyrrole‐2‐carboxylate have been developed involving the trans‐esterification of ethyl 3,5‐dimethyl‐pyrrole‐2‐carboxylate and the de‐acetylation of benzyl 4‐acetyl‐3,5‐dimethyl‐2‐carboxylate, both precursors being easily obtained using the Knorr reaction. These traditional methods involve treatment of the known products with a strong basic solution or heating for extended periods which often lead to decomposition. The use of microwave energy to promote these two reactions proves to be an extremely efficient way to obtain benzyl 3,5‐dimethyl‐pyrrole‐2‐carboxylate quickly, in high yield, and in excellent purity with no need for recrystallization. Of particular note is the use of catalytic sodium methoxide in benzyl alcohol, rather than stoichiometric amounts of sodium benzoxide, to effect benzylation.
A facile regioselective synthesis of (5‐amino‐4‐cyano‐1h‐imidazol‐1‐yl) benzoic acids
Authors: Barros Síria A. , Gonçalves M. Sameiro T. , Oliveira‐Campos Ana M. F. , Proença Fernanda R. P.
Published: March 2009

magnified image

A simple and efficient method was developped for the synthesis of 3‐(5‐amino‐4‐cyano‐1H‐imidazol‐1‐yl)‐4‐substituted benzoic acids 3. These compounds were isolated by intramolecular cyclisation of the corresponding 3‐{[(Z)‐2‐amino‐1,2‐dicyano‐vinyl]amino}methyleneaminobenzoic acids in the presence of base.
Synthesis of some thiazolyl and thiadiazolyl derivatives of substituted furan and pyrrole
Authors: Hassan Seham Y.
Published: March 2009

magnified image

Four series of substituted furan and pyrrole have been synthesized. The first series was prepared by cyclization of the key intermediates ethyl 5‐[(4‐substituted thiosemicarbazido)methyl]‐2‐methylfuran‐3‐carboxylates 2a‐2d and 1‐[(4‐acetyl‐5‐methyl‐1H‐pyrrol‐2‐yl)methylene]‐4‐substituted thiosemicarbazides 8a‐8d with chloroacetic acid or (ethyl bromoacetate) to afford the corresponding 4‐oxo‐3‐substituted thiazolidin‐2‐ylidene 3a‐3d or 3‐substituted thiazolidin‐4‐one 9a‐9d. On the other hand, heating of the intermediates 2a‐2d or 8a‐8d with acetic anhydride afforded the corresponding (N‐substituted acetylamino)‐2,3‐dihydro‐[1,3,4]thiadiazol‐2‐yl derivatives 4a‐4d and [1,3,4]thiadiazol‐2‐yl‐N‐substituted acetamide 10a‐10d respectively, while cyclization with p‐bromophenacyl bromide gave rise to the corresponding 3‐substituted thiazol‐2‐yl‐ylidene 5a‐5d and 11a‐11d respectively. Furthermore, 4‐oxo‐3‐substituted thioureido‐thiazolidin‐2‐yl 6a‐6d or 4‐oxo‐thiazolidin‐3‐yl‐3‐substituted thiourea 12a‐12d were obtained by reaction of the intermediates 2a‐2d or 8a‐8d with thioglycolic acid. Some of the synthesized compounds showed promising antimicrobial activities.
Synthesis and antimicrobial activity of novel spirocompounds with pyrazolone and pyrazolthione moiety
Authors: Chande Madhukar S. , Barve Pravin A. , Suryanarayan Vijay
Published: March 2009

magnified image

The paper focuses on the utility of 2‐pyrazoline‐5‐ones and 2‐pyrazoline‐5‐thiones as active Michael donors for the synthesis of novel spirocyclohexanone derivatives. The sulphur containing compounds when screened for antimicrobial activity showed promising inhibition of S. Typhi, S Aures and E Coli bacteria.
Thio analogs of pyrimidine bases: Syntheses and EIMS study of new ortho‐(meta‐ and para‐)bromobenzyl s‐mono and S‐N‐1‐disubstituted 5‐morpholinomethyl(5‐piperidinomethyl)‐2‐thiouracils
Authors: Wyrzykiewicz Elżbieta , Pospieszny Tomasz
Published: March 2009

magnified image

Eleven new ortho‐(meta‐ and para‐)bromobenzyl S‐mono and S‐N‐1‐disubstituted derivatives of 5‐morpholinomethyl‐2‐thiouracil (MMTU) and 5‐piperidinomethyl‐2‐thiouracil (PMTU) have been prepared and their EI induced mass spectral fragmentation has been investigated. It has been shown that the data derived from EIMS spectra can be used to differentiate the isomers
New reaction of schiff base with dimedone: New method for the acridine derivatives under microwave irradiation
Authors: Tu Shujiang , Li Tuanjie , Zhang Yan , Shi Feng , Xu Jianing , Wang Qian , Zhang Jinpeng , Zhu Xiaotong , Jiang Bo , Jia Runhong , Zhang Junyong
Published: March 2009

magnified image

A novel cascade reaction of Schiff's base was described. The products afforded in the reaction depended on the ratio of the two starting materials. A possible mechanism of the reactions is proposed, which underwent the breaking and new formation of the bond between carbon atom and nitrogen atom.
Synthesis of 1,4‐disubstituted 1,2,3‐triazoles via a three‐component reaction in water in the presence of cux (X = Cl, I)
Authors: Wang Zhong‐Xia , Zhao Zhi‐Gang
Published: March 2009

magnified image

Three‐component reaction of alkyl halides, sodium azide and alkynes in water in the presence of CuX (X = Cl, I) afforded 1,4‐disubstituted 1,2,3‐triazoles in high yields. These reactions do not require any special precautions or existence of a reducing agent. The bistriazoles formed during the reaction can efficiently enhance the catalytic activity of the Cu(I) salts.
Synthesis of propionamide pyridine and pyridine n‐oxide ligands
Authors: Binyamin Iris , Pailloux Sylvie , Duesler Eileen N. , Paine Robert T. , Hay Benjamin P. , Rapko Brian M.
Published: March 2009

magnified image

A new set of pyridine and pyridine N‐oxides functionalized with N,N‐dimethylpropionamide pendant groups in the 2‐ and 2,6‐positions have been prepared from the combination of 2‐chloromethylpyridine and 2,6‐bis(chloromethyl) pyridine with α‐lithio N,N‐dimethyl acetamide. The coordination interaction between 2‐(N,N‐dimethylpropionamide) pyridine N‐oxide (10) and Tb(NO3)3 has been unambiguously defined via single crystal X‐ray diffraction analysis of Tb(10)(NO3)3(H2O).
Synthesis of novel 3,5,7‐triaryl‐5,6‐dihydro‐4h‐1,2,5‐triazepines
Authors: Ravindran Gurusamy , Muthusubramanian Shanmugam , Selvaraj Sanguvan , Perumal Subbu
Published: March 2009

magnified image

Several hitherto unknown 3,5,7‐triaryl‐5,6‐dihydro‐4H‐1,2,5‐triazepines have been synthesised by cyclocondensation of N,N‐bis(phenacyl)anilines with hydrazine hydrate in ethanol or ethyleneglycol under reflux condition. Increased yields were obtained in the presence of p‐toluenesulfonic acid compared to the uncatalysed reaction.
1,3‐Dipolar cycloadditions: Investigation of cycloadditions of c‐aryl‐n‐(4‐chlorophenyl) nitrones to n‐cinnamoyl piperidines
Authors: Banerji Avijit , Biswas Pizush Kanti , Bandyopadhyay Debasish , Gupta Maya , Prangé Thierry , Neuman Alain
Published: March 2009

magnified image

Investigation of cycloadditions of C‐aryl‐N‐(4‐chlorophenyl)nitrones to N‐cinnamoyl piperidines was carried out. Two diastereoisomeric and one regioisomeric cycloadducts, and in some cases ring‐opened compounds were characterized by spectroscopic and X‐ray data. Molecular modelling was carried out for conformational studies.
Synthesis and structure elucidation of 3,4‐dihydroxy‐2‐quinolin‐2‐ylpyrido[3,2,1‐jk]carbazol‐6‐ones
Authors: Dang Hoai V. , Habib Nargues S. , Kappe Thomas , Zangger Klaus , Stadlbauer Wolfgang
Published: March 2009

magnified image

3,4‐Dihydroxy‐2‐quinolin‐2‐ylpyrido[3,2,1‐jk]carbazol‐6‐ones 6 were obtained by cyclocondensation of carbazole 1 with malonates 2 in the presence of quinoline. The assignment of the structures of 6 was performed by NMR experiments such as 1D 1H, 13C and DEPT, as well as 2D COSY, HSQC, HMBC and 1,1‐ADEQUATE spectra.
Synthesis of crown ethers bearing 2,4‐dinitrophenylhydrazone
Authors: Abdurrahmanoglu Saziye , Bulut Mustafa
Published: March 2009

magnified image

The o‐dihydroxy‐ (2a‐b), dimethoxy (3a‐b), ethylendioxy‐ (4a‐b) and macrocyclic polyethers (4c‐i) are the initial compounds while the 2,4‐dinitrophenylhydrazone compounds (5a‐d, 6a‐i) represent new derivatives. Novel hydrazone compounds were synthesized from the corresponding cyclic ketones (4a‐i) and 2,4‐dinitrophenylhydrazine in H2SO4/EtOH/H2O solution at room temperature for 1 h. The structures of obtained hydrazone compounds were confirmed by 1H‐NMR, 13C‐NMR, EI‐MS, IR spectra and elemental analysis.
Phase transfer catalyzed synthesis of 3‐methyl‐4h‐pyrazolo[3,4‐d]isoxazole from 3,5‐dimethyl‐4‐isoxazolyldiazonium tetrafluoroborate
Authors: Rajanarendar E. , Mohan G. , Ramesh P. , Srinivas M.
Published: March 2009

magnified image

Reaction of 3,5‐dimethyl‐4‐isoxazolyl‐diazonium tetrafluoroborate (2) with two equivalents of potassium acetate and five mole percent of 18‐crown‐6 in ethanol‐free chloroform produce 3‐methyl‐4H‐pyrazolo[3,4‐d]isoxazole (3) in good to excellent yield. Pyrazole (3) was subjected to acylation/aroylation to afford the corresponding 4‐N‐acetyl/aroyl derivatives by reaction with CH3COCl/ArCOCl in Et3N.
Flash vacuum pyrolysis of 1‐azolyl‐1‐phenylhydrazono‐2‐propanones
Authors: El‐Dusouqui Osman M. E. , Dib Hicham H. , Al‐Awadi Nouria A. , Abdelkhalik Mervat M. , Al‐Etaibi Alya M.
Published: March 2009

magnified image

Flash vacuum pyrolysis (FVP) of 1‐(2‐arylhydrazono)‐1‐(1H‐1,2,4‐triazol‐1‐yl)acetone 8a‐c at 650 °C and 2.67 Pa yielded 5‐substituted 1‐(1H‐indazol‐3‐yl)ethanone 14a‐c and 4,6‐disubstituted cinnoline 18a‐c. Similarly FVP of 1‐(1H‐benzo[d]imidazol‐1‐yl)‐1‐(2‐phenylhydrazono)acetone 9a‐c gave 8H‐benzo[4′,5′]imidazo[2′,1′:5,1]pyrrolo[2,3‐c]cinnoline derivatives 23a‐c. A plausible mechanism is suggested to account for their transformation based on the kinetics and products of reaction.
Convenient syntheses of perdeuterated ionic liquids
Authors: Dzyuba Sergei V. , Li Shengfu , Bartsch Richard A.
Published: March 2009

magnified image

Facile, gram‐scale, one‐pot or two‐step syntheses for two different types of perdeuterated room‐temperature ionic liquids from commercially available starting materials are described.
Synthesis of α‐diaminomethylenebutyrolactams by the reaction of α‐cyanobutyrolactams with n‐trimethylsilylamines
Authors: Okabe Fumi , Nakamura Syouhei , Yamagata Kenji
Published: March 2009

magnified image

Successive treatment of α‐cyanobutyrolactams 1 with N‐trimethylsilylamines and water gave the corresponding α‐diaminomethylenebutyrolacatms 2 in good yields. In the NOESY spectra of 2, the E isomer, the NOE observed between β‐CH2 (butyrolactam) and N‐CH2 (morpholine, pyrrolidine) or N‐CH3 (dimethylamine) indicated a cis configuration of these groups.
Regiospecific synthesis of trichloromethyl substituted 4,5‐dihydro‐1h‐1‐tosylpyrazoles
Authors: Bonacorso Helio G. , Wentz Alexandre P. , Lourega Rogério V. , Cechinel Cleber A. , Moraes Tatiana S. , Flores Alex F. C. , Zanatta Nilo , Martins Marcos A. P.
Published: March 2009

magnified image

The regiospecific synthesis of a new series of eight 3‐alkyl(aryl)‐5‐hydroxy‐5‐trichloromethyl‐4,5‐dihydro‐1H‐1‐tosylpyrazoles is reported. The 1‐p‐tosyl‐2‐pyrazolines were obtained from the cyclocondensation reaction of 4‐alkyl(aryl)‐4‐alkoxy‐1,1,1‐trichloroalk‐3‐en‐2‐ones, [where alkyl = H, Me and aryl = ‐C6H5, 4‐CH3C6H4, 4‐OCH3C6H4, 4‐FC6H4, 4‐ClC6H4, 4‐BrC6H4,] with p‐tosylhydrazine in 64 to 92 % yields, employing anhydrous toluene at reflux or diethyl ether at room temperature as the reaction condition.
Azulene‐substituted pyridines and pyridinium salts. Synthesis and structure. 2. Azulene‐substituted pyridinium salts
Authors: Razus Alexandru C. , Birzan Liviu , Pavel Claudia , Lehadus Oana , Corbu Andreea , Chiraleu Filip , Enache Cristian
Published: March 2009

magnified image

4‐Azulen‐1‐yl substituted 2,6‐dimethyl‐and 2,6‐diphenyl‐pyridinium salts are obtained in yields between 50 % and 100 % in the reaction of corresponding 4‐azulen‐1‐yl‐pyranylim salts and various amines. The effects of amine structure and of substitution in the heterocycle or at azulene moieties on the synthesis have been investigated. The uv‐vis and NMR spectra of reaction products are examined and discussed in correlation with their structure.
Preparation of 5‐methyl‐2‐sulfanyl‐7h‐1,3,4‐thiadiazolo[3,2‐a]‐pyrimidin‐7‐ones
Authors: Safarov Saifidin , Kukaniev Muhamacho A. , Karpuk Elena , Meier Herbert
Published: March 2009

magnified image

7H‐1,3,4‐Thiadiazolo[3,2‐a]pyrimidin‐7‐ones can be prepared by the acylation of 5‐amino‐1,3,4‐thiadiazoles with diketene and subsequent ring closure (dehydration). Whereas arylthio substituents (SC6H5) can be introduced in 2‐position by the replacement of Br, alkylthio groups (SC2H5) have to be already presentin the starting 5‐amino‐1,3,4‐thiadiazole. The ambident nucleophile 2‐thiazolidinethione reacts in the Br substitution reaction on the N atom.
An improved synthesis of 1‐acetyl‐1H‐indol‐3‐yl acetates
Authors: Rodríguez‐Domínguez Juan C. , Balbuzano‐Deus Alexander , López‐López Miguel A. , Rodríguez‐Domínguez Juan C. , Kirsch Gilbert
Published: March 2009

magnified image

An efficient two steps procedure for the synthesis of 1‐acetyl‐1H‐indol‐3‐yl acetates, starting from 2‐chlorobenzoic acids, was developed and in general, moderate to good yields were obtained
Synthesis and characterization of some important indazolyl derivatives
Authors: Kale S. B. , Karale B. K.
Published: March 2009

magnified image

A series of some important indazolyl derivatives of pyrazoles, diazepines, thiopyrimidines, thiazines and chromones were synthesized and characterized with the help of spectral data. Some of the synthesized compounds are tested for antimicrobial and antioxidant activities.
Substituted quinolinones. Part 13 a convenient route to heterocyclization reactions with 3‐substituted 4‐hydroxyquinolin‐2(1H)‐one
Authors: Abdel‐Megid Mohamed , Abass Mohamed , Hassan Mohamed
Published: March 2009

magnified image

The reactivity of 3‐[(dimethylamino)prop‐2‐enoyl]‐4‐hydroxyl‐1‐methylquinolin‐2(1H)‐one (2) towards different nucleophilic and electrophilic reagents was investigated. The convenient synthesis of several 3‐heterocyclyl‐quinolinones such as 3‐pyridazinyl‐ 10, 11, 3‐pyranyl 19a,b and 3‐pyrazolylquinolinones 20a,b, 22, 26a,b, 27a,b, 31 and 33 has been described starting from the 3‐acetylquinolinone 1 and enaminone 2. In addition, certain heterocyclo[c]quinolinones such as pyrimido‐ 12, 14 pyrano‐ 3, 17a,b and pyrazolopyranoquinolinone 29 were obtained in good yields.
Chemical properties of 4,5‐di(ethoxycarbonyl)‐1,3‐dioxolan‐2‐yl (DECDO) as a hydroxyl protecting group of the 2′‐hydroxyl function in ribonucleosides
Authors: Karwowski Boleslaw , Seio Kohji , Sekine Mitsuo
Published: March 2009

magnified image

We describe basic chemical properties of 4,5‐di(ethoxycarbonyl)‐1,3‐dioxolan‐2‐yl (DECDO) in view of its use as a protecting group for the 2′‐hydroxyl function of ribonucleosides. The DECDO group is found to be compatible with the DMTr strategy for the currently‐used oligonucleotide synthesis. Post‐synthetic treatment with ammonia results in the conversion of this protecting group into the 4,5‐dicarbamoyl‐1,3‐dioxolan‐2‐yl (DCBDO) group which is unexpectedly more stable in aqueous acidic solution.
A study on chemical behaviors of some 4‐pyrones synthesized by one‐step reactions towards various amines
Authors: Şener Ahmet , Eskinoba Siddik , Bildirici İshak , Genç Hasan , Kasimoǧullari Rahmi
Published: March 2009

magnified image

Cycloaddition of acetylbenzoyl ketene generated in situ as an intermediate during one‐step reaction between excess benzoylacetone and oxalylchloride to C=C double bond of cyclic enol form of benzoylacetone gave 3‐acetyl‐5‐benzoyl‐6‐methyl‐2‐phenyl‐4(4H)‐pyrone 1a. Condensation reactions of 1a together with 3,5‐dibenzoyl‐2,6‐diphenyl‐4(4H)‐pyrone 1b and 3‐benzoyl‐5‐ethoxycarbonyl‐2,6‐diphenyl‐4(4H)‐pyrone 1c with two‐fold excess primary amines provided a series of 3‐benzoyl‐1‐alkyl‐5‐(1‐alkylimino‐ethyl)‐6‐phenyl‐2‐methyl‐4(1H)‐pyridinone 2, 3,5‐dibenzoyl‐1‐alkyl‐2,6‐diphenyl‐4(1H)‐pyridinone 3a‐c and 3‐benzoyl‐1‐alkyl‐5‐ethoxycarbonyl‐2,6‐diphenyl‐4(1H)‐pyridinone 3d,e derivatives, respectively. In addition, while prolonged reaction of n‐pentylamine with unsymmetrical pyrone derivative 1a gives a symmetrical pyridinone derivative namely 3,5‐dibenzoyl‐2,6‐dimethyl‐1‐pentyl‐4(1H)‐pyridinone 5, much prolonged action n‐pentylamine and then aqueous n‐pentylamine on 1b resulted in degradation of the 4‐pyrone ring to give dibenzoylmethane.
Synthesis of 5‐[(4‐phenylpiperazin‐1‐yl)methyl]pyrrolo‐[2,3‐d]pyrimidine derivatives as potential dopamine D4 receptor ligands
Authors: Linz Sabine , Troschütz Reinhard
Published: March 2009

magnified image

A series of pyrrolo[2,3‐d]pyrimidine Mannich bases of type 9, 12, 15 and 16 have been prepared as potential dopamine D4 receptor ligands. The syntheses start from 4‐aminopyrimidin‐6‐one 3 with pyrrole annulations and Mannich reactions with formaldehyde and phenylpiperazines 8 as new amine components.
Synthesis of new terpolymers with heterocyclic pendant groups
Authors: Vega Isabel N. , Sánchez Leonardo , D'Accorso Norma B.
Published: March 2009

magnified image

Chemical modifications of polyacrylonitrile (PAN), an inexpensive and commercial homopolymer, to obtain terpolymers containing 1,2,4 or 1,3,4 oxadiazolic pendant groups are described. These new materials are physically and spectroscopically characterized.
A new series of non‐classical type C heteropentalenes: 2H‐pyrrolo[2,1‐c][1,2,4]triazoles
Authors: Moderhack Dietrich , Schneider Jan‐Christoph
Published: March 2009

magnified image

7‐Functionalized title compounds 5 are obtained by cyclization of 3‐acetonyl‐ or 3‐[(alkoxycarbonyl)‐methyl]‐4‐phenacyl‐1,2,4‐triazolium salts 2 having methyl at C(5) the process can be effected in an acetate buffer or by base, irrespective of the function at C(3). 5‐Unsubstituted salts 2 do not react unless the side chain at C(3) is an acetonyl group. Cyclization of 2 with acetic anhydride‐base gives rise to 5,7‐difunctionalized compounds 8; again methyl at C(5) of 2 is compulsory, but here the reaction can be extended to salts having an (alkoxycarbonyl)methyl group at C(4). Regarding defunctionalization, acetyl groups can be split from C(5) only, whereas ester functions are removable also from C(7). Title compounds devoid of acceptor groups (XIII) are unstable but can be trapped by electrophilic reagents (DMAD, acetic anhydride, and phenyl isocyanate) to give the derivatives 10 and 12. The 7‐functionalized products 5 are likewise susceptible to SE‐reactions. By comparison, all title compounds appear to be more reactive toward this kind of reagents than the isomeric 1H‐pyrrolotriazoles (13) including 2H‐pyrrolotetrazoles (III). This is consistent with B3LYP‐DFT calculations using appropriate models.
Synthesis of novel 3,4‐diaryl‐1H‐pyrroles
Authors: Shafiee Abbas , Kassaee Mohammad Z. , Bekhradnia Ahamad R.
Published: March 2009

magnified image

The synthesis of a series of novel 3,4‐diaryl‐1H‐pyrroles and related arylalkenes from p‐bromo thiophenol, tosylmethyl isocyanide and commercially available materials is reported. Arylalkenes having electron‐withdrawing substituents gave higher yield of 3,4‐diaryl‐1H‐pyrroles.
Stability in solution of indolium heptamethine cyanines and related pH‐sensitive systems
Authors: Strekowski Lucjan , Lee Hyeran , Mason J. Christian , Say Martial , Patonay Gabor
Published: March 2009

magnified image

Relative stabilities of methanolic solutions of dyes that are potentially important for labeling of biological macromolecules with a visible‐red or near‐infrared fluorophore were evaluated in the presence of molecular oxygen under dark and light conditions.
An efficient and modified biginelli one‐pot synthesis of new isoxazole substitted 3,4‐dihydropyrimidin‐2(1H)‐ones and thiones catalyzed by VCl3
Authors: Rajanarendar E. , Ramesh P. , Mohan G. , Rao E. Kalyan
Published: March 2009

magnified image

An efficient and modified Biginelli one‐pot synthesis of new‐isoxazole substituted 3,4‐dihydropyrimidin‐2(1H)‐ones and thiones from aromatic aldehydes, ketoamide and urea/thiourea in acetonitrile using VCl3 as the catalyst is described.
One‐pot synthesis of symmetrically disubstituted 3H‐phenoxazin‐3‐ones by selective oxidative condensation with LTA
Authors: Sridharan Vellaisamy , Dhanalakshmi Pandi , Muthusubramanian Shanmugam
Published: March 2009

magnified image

A one‐pot synthesis of some new 2,8‐disubstituted 3H‐phenoxazin‐3‐ones from 4‐substituted‐2‐aminophenols through a selective oxidative condensation by lead tetraacetate in acetic acid is described.