bluuebunny/crossref_metadata_2025 huggingface dataset:
Microwave induced synthesis of the thiazolidine‐2,4‐dione motif and the efficient solvent free‐solid phase parallel syntheses of 5‐benzylidene‐thiazolidine‐2,4‐dione and 5‐benzylidene‐2‐thioxo‐thiazolidine‐4‐one compounds
Authors: Kumar B. R. Prashantha , Nanjan M. J. , Suresh B. , Karvekar M. D. , Adhikary L.
Published: March 2009

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Novel microwave induced method for the synthesis of thiazolidine‐2,4‐dione motif under solvent phase conditions is developed. Further we report an efficient, microwave assisted method for the parallel syntheses of biologically important 5‐benzylidene‐thiazolidine‐2,4‐dione and 5‐benzylidene‐2‐thioxothiazolidine‐4‐one compounds under solid‐phase and solvent‐free conditions. A comparative study between the developed microwave methods and the conventional methods is described. We have also illustrated the possible mechanism behind to address the reason why piperidine, acetic acid and silica gel enhanced the Knoevenagel condensation reaction.
Synthesis, structure and biological activities of [α‐(alkylcarbonyl)‐2‐(1,2,4‐triazol‐1‐yl)]ethyl‐N,N‐dialkydithiocarbamate derivatives
Authors: Jian Fangfang , Xiao Hailian , Zhu Chongyi , Xu Liangzhong
Published: March 2009

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Seven 1,2,4‐triazole compounds containing the N,N‐dialkyldithiocarbamate group were designed and synthesized. Their structures were identified using infrared spectroscopy, element analysis, 1H NMR spectroscopy and mass spectrometry, and in two cases by single crystal X‐ray diffraction. The result of the biological test showed that the seven compounds all have fungicidal and plant growth‐regulating activities.
Behavior of 3‐benzylamino‐5‐aryl‐2(3H)‐furanones towards some nitrogen nucleophiles
Authors: Kandeel Kamal A. , Youssef Ahmed S. A. , Abou‐Elmagd Wael S. I. , Hashem Ahmed I.
Published: March 2009

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Ring closure of 2‐N‐benzylamino‐3‐aroylpropionic acids (3) with acetic anhydride afforded 3‐N‐benzylamino‐5‐aryl‐2(3H)‐furanones (4). The reaction of the furanones (4) with benzylamine in benzene was found to be time dependent. Thus refluxing the reaction mixture for 1 h only afforded the open‐chain amides (5a‐c). When the reaction was conducted for 3 h the 2(3H)‐pyrrolones (6) were obtained. Hydrazine hydrate affected ring opening of the furanones to give the hydrazides (5d‐f). Also, semicarbazide converted (4) into the corresponding semicarbazide derivatives (5g‐i). The hydrazides (5d‐f) were reacted with benzoyl chloride to give the corresponding diaroylhydrazines (5j‐l). The open‐chain derivatives (5) were converted into a variety of heterocycles: isothiazolones (7), dihydropyridazinones (8), 1,3,4‐oxadiazoles (9) and 1,2,4‐triazole derivatives (10) via cyclization reactions.
The reaction of aryl and heteroarylhydrazines with aryl‐trifluoromethyl β‐diketones
Authors: Singh Shiv P. , Kumar Vinod , Aggarwal Ranjana , Elguero Jose
Published: March 2009

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We report the results obtained when five aromatic or heteroaromatic hydrazines react with six β‐diketones bearing trifluoromethyl and aryl substituents. Forty‐two compounds have been isolated corresponding to two isomeric trifluoromethyl pyrazoles and the intermediate 5‐CF3, 5‐OH pyrazolines. The results have provided useful information for establishing the mechanism of the synthesis of pyrazoles.
Dibenzo‐fused seven‐membered nitrogen heterocycles by a tandem reduction‐lactamization reaction
Authors: Bunce Richard A. , Schammerhorn James E.
Published: March 2009

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Efficient syntheses of dibenz[b,f][1,4]oxazepin‐11(10H)‐one, 5,10‐dihydro‐11H‐dibenzo[b,e][1,4]‐diazepin‐11‐one and 5,11‐dihydro‐6H‐dibenz[b,e]azepin‐6‐one are described using a tandem reductionlactamization sequence. Precursors for these ring systems are available in 1‐3 steps using nucleophilic aromatic substitution and Ullmann coupling methodology. Direct reduction‐lactamization of these compounds using iron powder in acetic acid at 115° affords the target heterocycles in ≥90% yield.
Synthesis of new heteroaromatic nitrogen ligands: Pyrimido‐[4″,5″:4′,5′]‐thieno[3′,2′:4,5]thieno[3,2‐d]pyrimidines and 1,2,3‐triazine[4″,5″:4′,5′]thieno[3′,2′:4,5]thieno[3,2‐d]‐1,2,3‐triazines
Authors: Blanco Gerardo , Quintela José M. , Peinador Carlos
Published: March 2009

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An efficient one‐pot access for the synthesis of the previously unreported tetracyclic fused pyrimido‐[4″,5″:4′,5′]thieno[3′,2′:4,5]thieno[3,2‐d]pyrimidine (3) and 1,2,3‐triazine[4″,5″:4′,5′]thieno‐[3′,2′:4,5]thieno‐[3,2‐d]‐1,2,3‐triazine (5) heteroaromatic nitrogen ligands is described. The title compounds 3 and 5 were obtained from 3,4‐diaminothieno[2,3‐b]thiophene‐2,5‐dicarbonitrile and phosgeniminium chloride and sodium nitrite/HCl, respectively. Substituted condensed thieno[2,3‐b]thiophene derivatives 4 and 6 were synthesized by nucleophilic displacement of the chloroderivatives 3 and 5.
Synthesis of N‐amino‐3‐hydroxy‐2‐phenyl‐4(1H)‐quinolinone
Authors: Spáčilová Lucie , Hlaváč Jan , Hradil Pavel , Fryšová Iveta , Soural Miroslav , Krejčí Petr , Maloň Michal
Published: March 2009

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2‐[(Disubstituted‐methylene)‐hydrazino] benzoic acid phenacylesters 2a‐2d, prepared from anthranilic acid phenacylester 1, were unsuccesfully tried as starting materials for the synthesis of N‐amino‐3‐hydroxy‐2‐phenyl‐4(1H)‐quinolinone 8. The desired compound 8 was prepared by cyclization of N‐acetyl as well as N‐benzoyl‐hydrazinobenzoic acid phenacylester 6a or 6b in polyphosphoric acid to afford N‐acylamino‐3‐hydroxy‐2‐phenyl‐4(1H)‐quinolinone 7a or 7b, respectively. Surprisingly, the acyl group was resistant to attack by both hydrochloric acid as well as sodium hydroxide solution. It could be removed by boiling the compounds 7a or 7b respectively in 50% sulphuric acid to afford the the target compound 8.
Study of the pyrimidine nucleobase C5C6 bond reactivity under thio‐michael/aldol tandem reaction conditions
Authors: Velez Edna Vázquez , Desnous Céline , Clivio Pascale
Published: March 2009

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Pyrimidine nucleobases can undergo a Michael/aldol tandem reaction triggered by a thiolate. In an intramolecular context, 5′‐deoxy‐2′,3′‐isopropylidene‐5′‐thiouridine affords the reminiscent Baylis‐Hillman adduct after retro‐Michael addition whereas its thymine counterpart is unreactive. In an intermolecular context, the conjugate addition‐aldol reaction occurs only if the C5C6 double bond is activated.
Synthesis of new peptide nucleic acid monomer with glycylglycine backbone
Authors: Yamasaki Tetsuo , Watanabe Akiko , Sakamoto Masanori , Otsuka Masami , Abdel‐Aziz Mohamed , Iwashita Takashi
Published: March 2009

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New thymine peptide nucleic acid (PNA) monomer with glycylglycine backbone was prepared. This involved a key step of the coupling between iodinated serine (3) and 3‐benzoylthymine.
Formation of pyridazino[4,5‐c]pyridazine derivatives upon [4+2]cycloaddition of 4‐phenyl‐1,2,4‐triazoline‐3,5‐dione to cross‐conjugated monoferrocenyltrienes
Authors: Martínezmendoza Juan M. , Vázquez López Eduardo A. , Esparza Rafael Moreno , Alamo Marcos Flores , Klimova Elena I.
Published: March 2009

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Cross‐conjugated monoferrocenyltrienes react with 4‐phenyl‐1,2,4‐triazoline‐3,5‐dione to give mono‐ and bis‐[4+2]‐cycloaddition products. Nonsubstituted and 2,4‐disubstituted 3‐ferrocenylmethylidenepenta‐1,4‐dienes afford respective pyridazine and pyridazino[4,5‐c]pyridazine derivatives. Their structures were established based on1H and13C NMR data and X‐ray diffraction analysis.
A facile synthesis of some substituted furopyrimidine derivatives
Authors: Pyo Jung In , Lee So Ha , Cheong Chan Seong
Published: March 2009

Some substituted furopyrimidine derivatives are prepared in high yield in 4 steps, starting from the reaction of furoin (1,2‐di(furan‐2‐yl)‐2‐hydroxyethanone) and malonitrile.
Synthesis and alkylation of 5‐(3‐chlorobenzo[b]thien‐2‐yl)‐4H‐1,2,4‐triazole‐3‐thiol under classical and microwave conditions. AM1 semiemperical calculations for investigating the regioselectivity of alkylation
Authors: Ashry E. S. H. El , Kassem A. A. , Abdel‐Hamid H. , Louis F. F. , Khattab S. H. A. N. , Aouad M. R.
Published: March 2009

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Under microwave irradiation (MWI), 5‐(3‐chlorobenzo[b]thien‐2‐yl)‐4H‐1,2,4‐triazole‐3‐thiol (3) was synthesized in a good yield by intramolecular cyclization of the carbonyl thiosemicarbazide 2. A regioselective S‐alkylation of 3 with benzyl chloride or allyl bromide has been achieved by using triethylamine as a base, while other different basic conditions led to a mixture of bis(alkylated) derivatives N4, S‐ and S, N2‐, under both of classical and MWI conditions. The relative stabilities, charge densities, dipole moments and electronic energies of reactants, transition states and intermediates were calculated by the AM1 method and used for investigating the regioselectivity.
Thermal decomposition reactions of n‐alkylated 2‐aminobiphenyls to carbazole and phenanthridine
Authors: Creencia Evelyn Cuevas , Horaguchi Takaaki
Published: March 2009

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Thermal cyclization reactions were examined by passing vapors of N‐alkylated 2‐aminobiphenyls 1a‐c and 2 over calcium oxide at 450‐600°C under nitrogen carrier gas. The reactions yielded 9‐methylcarbazole 3, carbazole 4, phenanthridine 5 and phenanthrene 6. The major product for the reactions of 1a, 1b and 2 was phenanthridine 5 while that of 1c was carbazole 4.
Synthetic studies connected with the preparation of h+/k+‐ATPase inhibitors rabeprazole and lansoprazole
Authors: Rédl Stanislav , Klecén Ondřej , Havlíček Jaroslav
Published: March 2009

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Synthesis of lansoprazole and rabeprazole using common intermediates is devised. The common intermediates, 2‐[(4‐nitro‐3‐methylpyridin‐2‐yl)methanesulfanyl]‐1H‐benzoimidazole and 2‐[(4‐chloro‐3‐methyl‐pyridin‐2‐yl)methanesulfanyl]‐1H‐benzoimidazole, were prepared in several ways.
One‐pot synthesis of 2‐acylimino‐3‐aryl‐1,3‐thiazoline derivatives in aqueous media
Authors: Wang Xi Cun , Wang Fang , Quan Zheng Jun , Zhang Zhang , Wang Man Gang
Published: March 2009

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The one‐pot two‐step synthesis for acyliminothiazolines by treatment of N,N'‐substituted thioureas with α‐bromocarbonyl compounds under aqueous media was described. Compared to classical reaction in organic solvents, this method consistently has the advantages of short reaction time and being environmentally friendly.
Intramolecular [4+2] cycloaddition of furfurylsubstituted homoallylamines to allylhalides, acryloyl chloride and maleic anhydride
Authors: Varlamov Alexey V. , Boltukhina Ekaterina V. , Zubkov Fedor I. , Nikitina Eugenia V. , Turchin Konstantin F.
Published: March 2009

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Acylation of 4‐(furyl‐2)‐4‐R‐aminobut‐1‐enes and 4‐R‐4‐furfurylaminobut‐1‐enes with maleic anhydride, acryloyl chloride or allylhalides provided 3‐aza‐10‐oxatricyclo[5.2.1.01,5]decenes. The tricycles are formed via an initial amide formation followed by a stereoselective exo‐IMDAF (Intramolecular Diels‐Alder of Furan). In case of competing cycloaddition (for compounds possessing two furan or two dienophilic moieties) the most substituted fivemembered cycle is preferably annulated. Refluxing of 4‐R‐4‐furfurylaminobut‐1‐enes in acetic anhydride led to exo‐3‐aza‐11‐oxatricyclo[6.2.1.01,6]undecenes with the pseudoequatorial substituent R‐4. Treatment of 3‐aza‐10‐oxatricyclo[5.2.1.01,5]decenes with PPA at 90−110°C promoted cyclic ether opening, aromatization and intramolecular cyclization reactions sequence to give the corresponding tetracyclic compounds — tetrahydroisoindolo[2,1‐a]quinolines and tetrahydroisoindolo[2,1‐b][2]benzazepines in good yields. Unusual products of ipso‐substitution in aromatic ring were obtained on cyclization of N‐p‐R‐substituted 2‐allyl‐4‐oxo‐3‐aza‐10‐oxatricyclo[5.2.1.01,5]dec‐8‐enes.
A facile access to indigodianiles
Authors: Kühn Christiane , Beckert Rainer , Friedrich Manfred , Görls Helmar
Published: March 2009

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Bis‐imidoylchlorides derived from oxalic acid can easily be transformed into the corresponding bis‐imino benzotriazoles. The fact that benzotriazole is a well‐established leaving group has been exploited for an improved synthesis of indigodianiles. Employing metallic lithium, the benzotriazoles can be converted in a cascade reaction into indigo bis‐arylimines in yields up to 45%. Formation of the reduced form of dimeric isocyanides is suggested as a key step.
Microwaves in organic synthesis: Synthesis of pyridazinones, phthalazinones and pyridopyridazinones from 2‐oxo‐arylhydrazones under microwave irradiation
Authors: Al‐Saleh Balkis , El‐Apasery Morsy Ahmed , Hilmy Noha M. , Elnagdi Mohamed H.
Published: March 2009

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The phenylhydrazones 1a‐d condensed with ethyl cyanoacetate to yield pyridazinones 2a‐d that reacted with sulphur in presence of piperidine to yield the aminothienopyridazineones 3a,b that reacted with electron poor olefins and acetylenes to yield phthalazines 10‐12. The condensed aminothiophenes 3a,b reacted with dimethylformamide dimethylacetal to yield amidines 13a,b. Compounds 2a,b condensed with dimethylformamide dimethylacetal to yield the trans enamines 16a,b that cyclized readily into the pyridopyridazinones 17a,b on treatment with ammonium acetate in presence of acetic acid. Compounds 2a‐d reacted also with benzylidenemalononitrile to yield the phthalazinones 21a‐d. The reactions were conducted both by microwave heating and conventional heating. Better yields in much shorter reaction times were achieved by microwave heating.
A simple two steps ytterbium triflate‐catalysed preparation of 2,2‐dimethyl‐2h‐chromenes from salicylaldehydes and 2‐methylpropene
Authors: Prado Soizic , Janin Yves L. , Bost Pierre‐Etienne
Published: March 2009

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The preparation of various 2,2‐dimethyl‐2H‐chromenes was achieved in two steps via an ytterbium triflate‐catalysed reaction between salicylaldehydes, trimethylorthoformate and 2‐methylpropene. From salicylaldehyde, two reaction products were characterised: 4‐methoxy‐2,2‐dimethylchroman and 2‐(1,3‐dimethoxy‐3‐methylbutyl)phenol. The former compound probably results from a Lewis acid‐catalysed [2+4] cycloaddition between the intermediate quinonemethide and 2‐methylpropene whereas the latter may occur via a reaction related to a carbonyl‐ene reaction between the quinonemethide and 2‐methylpropene. Both compounds were subjected to a catalytic acidic treatment leading to 2,2‐dimethyl‐2H‐chromene. Starting from various salicylaldehydes, the scope of this method was investigated.
An efficient one‐pot synthesis of polyhydrobenzoacridine‐1‐one derivatives under microwave irradiation without catalyst
Authors: Tu Shujiang , Jia Runhong , Jiang Bo , Zhang Yan , Zhang Junyong
Published: March 2009

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A series of 3,3‐dimethyl‐9‐substituted‐1,2,3,4,9,10‐hexahydrobenzo[c] acridine‐1‐ones and 3,3‐dimethyl‐9‐substituted‐1,2,3,4,9,10‐hexahydrobenzo[a] acridine‐1‐ones were synthesized by the reaction of an aldehyde, α‐naphthylamine or β‐naphthylamine and dimedone under microwave irradiation with short times and high yields.
An efficient one‐pot synthesis of n‐carboxymethylacridine‐1,8‐dione derivatives under microwave irradiation
Authors: Tu Shujiang , Wang Qian , Zhang Yan , Xu Jianing , Zhang Jinpeng , Zhu Xiaotong , Shi Feng
Published: March 2009

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A series of N‐carboxymethylacridine‐1,8‐dione derivatives were synthesized by one‐pot reaction of aldehyde, dimedone and glycine in glycol under microwave irradiation without catalyst with excellent yields (78‐92%) and short reaction time (4‐8min). And the reaction was not only suitable for aromatic monoaldehyde, but also aromatic dialdehyde.
Reaction of 2‐diazo‐1,2‐diarylethanones with benzophenone n‐(diaryl)acyl hydrazones: Formation of 1,3,4‐oxadiazolines
Authors: Singh Girija S.
Published: March 2009

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The reaction of 2‐diazo‐1,2‐diarylethanones with benzophenone N‐(diaryl)acyl hydrazones leads to the formation of 1,3,4‐oxadiazolines. The products have been characterized on the basis of satisfactory analytical and spectral (IR, 1H and 13C NMR, and Mass) data. The mechanism for the formation of products through the reaction of diarylketenes, generated in situ from thermal decomposition of the 2‐diazo‐1,2‐diarylethanones, with imino nitrogen and intramolecular [2 + 3] dipolar cycloaddition is suggested.
Synthesis of novel pyrazole‐linked norcantharidin derivatives of substituted aromatic amines with efficient 1,3‐dipolar cycloaddition
Authors: Deng Liping , Hu Yongzhou
Published: March 2009

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Highly efficient, practical and convient synthesis of fifteen compounds by the [3+2] 1,3‐dipolar cycloaddition reaction of norcantharidin derivatives of substituted aromatic amines with three hydrazines in the presence of Chloramine‐T.
Synthesis of bis‐intercalators with an aminochloropyrimidine ring as potential anticancer agents
Authors: Zhao Yuxiang , Yuan Hui Liang , Zajíčková Zuzana , Pérkényi Cyril
Published: March 2009

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The synthesis of a series of polymethylene chain‐bridged aminochloropyrimidines as potential DNA intercalators is described. N,N'‐Bis(2‐amino‐6‐chloro‐4‐pyrimidyl)‐1,3‐diaminopropane (3), N,N'‐bis(2‐amino‐6‐chloro‐4‐pyrimidyl)‐1,4‐diaminobutane (4), N,N'‐bis(2‐amino‐6‐chloro‐4‐pyrimidyl)‐1,6‐diaminohexane (5), N,N'‐bis(2‐amino‐6‐chloro‐4‐pyrimidyl)‐1,8‐diaminooctane (6), N,N'‐bis(2‐amino‐6‐chloro‐4‐pyrimidyl)‐1,10‐diaminodecane (7), and N,N'‐bis(2‐amino‐6‐chloro‐4‐pyrimidyl)‐1,12‐diaminododecane (8) were synthesized from 2‐amino‐4,6‐dichloropyrimidine (1) and 1,3‐diaminopropane, 1,4‐diaminobutane, 1,6‐diaminohexane, 1,8‐diaminooctane, 1,10‐diaminodecane, and 1,12‐diaminododecane, respectively. The spectral data and other physical properties of the new compounds are discussed.
A novel synthesis of some 2‐imino‐4‐thiazolidinone derivatives
Authors: Moghaddam Firouz Matloubi , Hojabri Leila
Published: March 2009

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An efficient and simple route is presented to the synthesis of some iminothiazolidinone derivatives. α‐Chloro amide derivatives undergo coupling reaction with isothiocyanate in the presence of a mild base, followed by nucleophilic substitution of chlorine by the sulfur atom of isothiocyanate.
Synthesis and spectral properties of 7‐(p‐bromophenyl)‐10,10‐dimethyl‐8‐alkylthio‐7,9,10,11‐tetrahydro‐benz[c]acridines and deprotection‐aromatization of 7‐[(o‐; and p‐substituted)phenyl]‐10,10‐dimethyl‐7,8,9,10,11,12‐hexahydrobenz[c]acridin‐8‐thione
Authors: Cortés Eduardo Cortés , García Concepcién Lozada , Montes Karla Sánchez , Obregón Rubén Sánchez , Maya Sandra Cortez , De Cortés Olivia García Mellado
Published: March 2009

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A series of sixteen new derivatives have been obtained and all have potentially useful pharmacological activity. The treatment of 7‐[(o‐chloro and p‐bromo)phenyl]‐7,8,9,10,11,12‐hexahydrobenz[c]acridin‐8‐one and Lawesson's reagent obtains the corresponding 7‐[(o‐ and p‐substituted) phenyl]‐10,10‐dimethyl‐7,8,9,10,11,12‐hexahydrobenz[c]acridin‐8‐thione II which was alkylated in presence of sodium hydride and the corresponding alkyl iodide under nitrogen atmosphere to obtain 8‐alkylthio‐7,9,10,11‐tetrahydro‐benz[c]acridines III, 1‐4. The thione II was desprotected and aromatized in presence of sodium hydride in absence of nitrogen atmosphere to produce a mixture of 7‐[(o‐ and p‐substituted)phenyl]‐10,10‐dimethyl‐8,9,10,11‐tetrahydrobenz[c]‐acridin‐8‐one IV, 1‐6 and 7‐[(o‐ and p‐substituted)phenyl]‐10,10‐dimethyl‐8‐hydroxi‐8,9,10,11‐tetrahydrobenz[c]acridine V, 1‐6. The structure of all products was corroborated by ir, 1H NMR, 13C NMR with bidimensional experiments and ms with CID experiments.
Studies with azoles and benzoazoles: A novel simple approach for synthesis of 3‐functionally substituted 3‐acylindoles
Authors: Abdel‐Motaleb Ramadan Maawad , Makhloof Abdel‐Moneim Abdel‐Salam , Ibrahim Hamada Mohamed , Elnagdi Mohamed Hilmy
Published: March 2009

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3‐Substituted acylindoles 8 are obtained via refluxing carboxylic acids with indole in acetic anhydride solutions. The formed 3‐substituted acylindole 8a is readily converted into 4‐aminopyrazol‐3‐ylindoles 20, and into 22. Indole reacts with chloroacetyl chloride to yield: 3‐chloroacetylindole 9 which could also be utilized for synthesis of a number of 3‐substituted indoles.
Microwave‐assisted synthesis of 2‐(2‐pyridyl)azoles. Study of their corrosion inhibiting properties
Authors: Likhanova Natalya V. , Martínez‐Palou Rafael , Veloz M. Aurora , Matías Diana J. , Reyes‐Cruz Victor E. , Höpfl Herbert , Olivares Octavio
Published: March 2009

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An efficient and fast procedure for the synthesis of 2‐(2‐pyridyl)azoles is described using ionic liquids as catalysts under microwave irradiation. The X‐ray crystallographic analyses for three of the four synthesized compounds are presented. Potentiodynamic polarization studies were carried out to analyze the electrochemical behavior of the compounds in corrosive acidic media. Of the four derivatives, one compound was detected to be an effective corrosion inhibitor prototype for oil refinery environments.
Synthesis and reactions of the thioamide derivatives of methyl vinyl ketone
Authors: Groś Łukasz , Wesołowska Aneta , Westerlich Sławomir , Jagodziński Tadeusz
Published: March 2009

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The reaction of isothiocyanates with in situ generated carbanions of α,β‐unsaturated ketones yielded α,β‐unsaturated keto thioamides which in the reaction with acids or bases cyclized to give 2,6‐disubstituted thiopyran‐4‐ones and in the reaction with α‐bromoesters gave thiazolidin‐4‐one derivatives. The thiopyran‐4‐ones reacted with α,β‐unsaturated aldehydes to yield tetrahydrothiopyran[2,3‐b]pyridin‐4‐ones, while thioanilides were formed in the reaction with phenyl isothiocyanate.
One‐pot synthesis of new 3‐substituted coumarins by tandem reactions
Authors: Bourahla Khadidja , Rahmouni Mustapha , Fraga‐Dubreuil Joan , Bazureau Jean Pierre , Hamelin Jack
Published: March 2009

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The synthesis of new 3‐substituted coumarins appended to imidazolium, pyridinium, 3‐dimethylamino pyridinium, 3‐chloro pyridinium and 3‐bromo pyridinium salts is reported. These salts were prepared by tandem reactions, followed by quantitative anionic metathesis. The structure of these new 3‐substituted coumarins was established by NMR (1H, 13C) and high‐resolution mass spectrometry.
Synthesis of nitropyrazolidines
Authors: Damavarapu Reddy , Surapaneni Rao , Duddu Raja , Farhor Farhad , Dave Paritosh , Parrish Damon
Published: March 2009

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Synthesis of 1, 2‐diacetyl‐4, 4‐dinitropyrazolidine 1 and results of further nitration of the 1,2‐diacetyl‐4,4‐dinitropyrazolidine are described.
Azulene‐substituted pyridines and pyridinium salts. Synthesis and structure. 1. Azulene‐substituted pyridines
Authors: Razus Alexandru C. , Birzan Liviu , Pavel Claudia , Lehadus Oana , Corbu Andreea , Chiraleu Filip , Enache Cristian
Published: March 2009

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4‐Azulen‐1‐yl substituted 2,6‐dimethyl‐and 2,6‐diphenyl‐pyridines are obtained in good yields from the reaction of corresponding 4‐azulen‐1‐yl‐pyranylium salts and ammonium acetate in ethanol or starting from 4‐chloro‐2,6‐diphenyl‐pyranylium salts in two steps: reaction with azulenes followed by in situ treatment with ammonium acetate. The effect of substitution at the 3‐position of the heterocycle was taken into account. The structure assignment was accomplished with NMR and uv‐vis spectra.
A new site‐selective route for synthesis of functionalized imidazo[2,1‐c][1,2,4]triazoles
Authors: Shawali Ahmad S. , Abdallah Magda A. , Mosselhi Mosselhi A. N. , Elewa Mahmoud S.
Published: March 2009

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Reactions of 4‐arylhydrazono‐2‐methylthio‐imidazolin‐5(1H)‐one 3 with various hydrazonoyl halides 1 proved to be site‐selective and yielded the respective imidazo[2,1‐c][1,2,4]triazole derivatives 8. The structure of the latter was elucidated by X‐ray analysis and the mechanism of the studied reactions was discussed.
Synthesis of a new series of pyrazolo[1,5‐a]pyrimidines structurally related to zaleplon
Authors: Baraldi Pier Giovanni , Fruttarolo Francesca , Tabrizi Mojgan Aghazadeh , Romagnoli Romeo , Preti Delia , Ongini Ennio , El‐Kashef Hussein , Carrión María Dora , Borea Pier Andrea
Published: March 2009

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The reaction between 3‐(dimethylamino)/3,3‐bis(methylthio)‐1‐(substituted)prop‐2‐en‐1‐ones and 4‐substituted‐5‐amino‐1H‐pyrazoles afforded new pyrazole[1,5‐a]pyrimidines structurally related to Zaleplon. The chemical modifications introduced at the 3‐, 5‐, and 7‐positions of the bicyclic structure revealed new promising candidates for the treatment of sleep disorders.
Synthesis and anti‐HIV‐1 activity of 1,3‐phenylene bis‐uracil analogues of MKC‐442
Authors: Aly Youssef L. , Pedersen Erik B. , La Colla Paolo , Loddo Roberta
Published: March 2009

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Reaction of 1,3‐phenylenediacetonitrile with the zinc organometallic reagent of ethyl 2‐bromobutyrate afforded the 1,3‐phenylene‐bis(acetoacetate) 2 which was used as the starting material for the synthesis of 1,3‐phenylene‐bis[6‐(2‐thiouracil)] 4. Desulphurization of 4 gave the corresponding bis‐uracil 6, which after silylation was N‐1 alkylated with bis(allyoxy)methane using TMS‐triflate as the catalyst or with chloromethyl ethyl ether to give the MKC‐442 analogues 7 and 9. The amino‐DABO and S‐DABO derivatives 11, 12a,b and 14 were also synthesized. The anti‐HIV‐1 activity test showed that when MKC‐442 analogues were constructed with 1,3‐phenylene in all cases they were detrimental to have activity against HIV‐1.
Synthesis of alicyclic N‐substituted 1,3‐amino alcohols via 1,3‐oxazines
Authors: Balázs Árpád , Szakonyi Zsolt , Fülöp Ferenc
Published: March 2009

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Alicyclic N‐substituted 1,3‐amino alcohols 13‐18 were prepared in a facile way in a one‐pot procedure from 1,3‐oxazines 5‐8 in the presence of a ketone 9‐12. The complex reaction involves palladium‐catalyzed reduction, debenzylation and/or transimination and further reduction.
Cyclization reactions of coumarin derivatives: Chemo‐ and regioselectivity effects of oxygen/sulfur isosteric replacement
Authors: Palmisano Giovanni , Toma Lucio , Annunziata Rita , Tagliapietra Silvia , Barge Alessandro , Cravotto Giancarlo
Published: March 2009

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We synthesized several sulfur isosters of ferulenol and related prenylcoumarins fromFerula communispreliminary to finding whether the antitubercular activity of these natural compounds might be dissociated from their antithrombin activity. Direct thionation of ferprenine, an instance of “diversity‐oriented” synthesis, yielded a mixture of three thiocoumarin derivatives. When 4‐hydroxy‐2‐deoxy‐2‐thiocoumarin was reacted with farnesal and other α,β‐unsaturated aldehydes, the isosteric oxygen‐sulfur substitution at position 2 surprisingly caused a regiochemical inversion in the tandem Knoevenagel‐electrocyclic reaction, prevalently affording the linear adduct. An extensive investigation with variously substituted enals highlighted a competition between Knoevenagel and Michael addition. This result was rationalized by energy calculations that took into consideration steric and electronic factors as well as complex formation with the catalyst.
Regiospecific synthesis of 5‐(1H‐indol‐2‐yl)‐1‐ and 2‐methyl‐6,7‐dihydro‐2H‐indazole isomers
Authors: Dandu Reddeppareddy , Tao Ming , Josef Kurt A. , Bacon Edward R. , Hudkins Robert L.
Published: March 2009

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A regiospecific approach to each N‐methyl‐5‐(1H‐indol‐2‐yl)‐6,7‐dihydro‐2H‐indazole isomer is reported. The 1‐methyl isomer 1 was prepared from 5‐bromo‐1‐methyl‐6,7‐dihydro‐1H‐indazole 3 and indole‐2‐boronate 5 by palladium catalyzed Suzuki coupling. The 2‐methyl regioisomer 2 was synthesized via addition of lithium (1‐carboxylato‐1H‐indole‐2‐yl)lithium 6 with 2‐methyl‐2,4,6,7‐tetrahydro‐indazol‐5‐one 8 followed by acid catalyzed dehydration.
A new synthesis method for benzo[f]quinolin‐3‐carbonyl urea and thiourea derivatives in aqueous media catalyzed by TEBAC
Authors: Wang Xiang‐Shan , Zhang Mei‐Mei , Zeng Zhao‐Sen , Shi Da‐Qing , Tu Shu‐Jiang , Wei Xian‐Yong , Zong Zhi‐Min
Published: March 2009

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A clean and simple synthesis procedure for benzo[f]quinolin‐3‐carbonyl urea and thiourea derivatives was developed based on the reaction between N‐arylidenenaphthalen‐2‐amine and barbituric acid or thiobarbituric acid in aqueous media catalyzed by triethylbenzylammonium chloride (TEBAC). It was interesting that the structures of products in solvent of DMSO‐d6 solution were different from those of the crystal states, which keep the enol form. The products were characterized by 1H NMR, and 13C NMR, and the crystal state was confirmed by X‐ray diffraction study of 3e. In addition, water was chosen as green solvent.
A convenient synthesis of 5‐alkylthio‐3,4‐diarylisoxazoles by palladium‐catalyzed coupling reactions
Authors: Eskandari Roozbeh , Navidpour Latifeh , Amini Mohsen , Shafiee Abbas , Shafaroodi Hamed , Shafiee Abbas
Published: March 2009

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Palladium‐catalyzed coupling reaction was found effective for rapid access to pharmacologically interesting 3,4‐diarylisoxazoles derivatives as selective COX‐2 inhibitors. Thus, the coupling reaction between 5‐alkylthio‐3‐aryl‐4‐iodoisoxazoles and arylboronic acids afforded the target 5‐alkylthio‐3,4‐diarylisoxazoles in good yields.
New route to pyrimido[4,5‐ e][1,3,4]thiadiazine derivatives
Authors: Rahimizadeh M. , Nikpour M. , Bakavoli M.
Published: March 2009

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5‐Bromo‐2‐chloro‐4‐methyl‐6‐(1‐methylhydrazino)pyrimidine is readily obtained from the recently reported 5‐bromo‐2,4‐dichloro‐6‐methylpyrimidine by treatment with methylhydrazine in chloroform. Treatment of this compound with carbon disulfide and several alkyl halides gave an intermediate which was successfully converted to its corresponding 3‐(alkylsulfanyl)‐7‐chloro‐1,5‐dimethyl‐1H‐pyrimido[4,5‐e][1,3,4]thiadiazine derivatives in basic acetonitrile. The latter compounds were reacted with secondary amines in boiling ethanol to afford the related 7‐amino derivatives.
Regioselective synthesis of quinazoline containing novel monoaryl ethers at room temperature
Authors: Deore Vijaykumar , Lohar Manoj V. , Yewalkar Nilambari , Mundada Ramswaroop , Ranaware Seema , Kumar Sanjay
Published: March 2009

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We are herein reporting the regioselective synthesis of quinazoline containing novel monoaryl ethers (quinazoline‐O‐Ar) (3a‐3j) at room temperature without any catalyst. From commercially available 2,4‐dichloro‐6,7‐dimethoxyquinazoline (1), 4‐chloro was selectively substituted with variety of electronically rich, electronically poor and electronically neutral phenols (2a‐2j). Reaction was carried out in DMF and NaH for 4‐6 hours at room temperature in fairly good yield. The products were purified (>98% pure, hplc) by crystallization to avoid the use of column chromatography.
Facile coupling of 2‐(1‐ethylthioethenyl)pyrroles with amines: A route to 2‐(1‐aminoethenyl)pyrroles and 1‐amino‐3‐iminopyrrolizines
Authors: Trofimov Boris A. , Sobenina Lyubov' N. , Mikhaleva Al'bina I. , Petrova Ol'Ga V. , Drichkov Vladislav N. , Ushakov Igor A. , Tarasova Ol'Ga A. , Toryashinova Darya‐Suren D. , Rusakov Yuriy Yu. , Krivdin Leonid B.
Published: March 2009

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2‐(2‐Cyano‐1‐ethylthioethenyl)pyrroles are readily coupled (50–55°) with primary and secondary amines at the position 1 of the ethenyl moiety to eliminate ethanethiol and afford 2‐(1‐amino‐2‐cyanoethenyl)pyrroles and/or their cyclic isomers ‐ functionalized 1‐amino‐3‐iminopyrrolizines in good to high yields.
Synthesis and biological evaluation of new benzo[f]furo[2,3‐h]‐and benzo[f]pyrano[2,3‐h]coumarin derivatives.
Authors: Tsoukka Maria , Litinas Konstantinos E. , Nicolaides Demetrios N. , Hadjipavlou‐Litina Dimitra J.
Published: March 2009

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Furocoumarins 3,5 and pyranocoumarin 7 were synthesized from the reaction of furonaphthalenediones 2,4 and pyranonaphthalenedione 6 respectively with carbethoxymethylene(triphenyl)phosphorane in refluxing DCM for 3‐6 hours or under microwave irradiation in toluene for a few minutes. Compounds 3,5,7 and their precursors were tested as anti‐inflammatory/antioxidant agents. They were found to compete significantly high DMSO for OH radicals, to scavenge O2− and to inhibit lipoxygenase to a high extent.
Synthesis of tacrine derivatives under solventless conditions
Authors: Khalilzadeh Mohammad A. , Hosseini Abolfazl , Tajbakhsh Mahmoud
Published: March 2009

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Effects of microwave irradiation on the solid‐phase synthesis of tacrine and its derivatives have been evaluated. Preparation of tacrine analogues under conventional conditions suffers from poor synthetic efficiency and usually gives low yield. Reaction of substituted anthranilonitrile with cyclohexanone under microwave irradiation gave a good to excellent yield of the corresponding substituted 9‐amino‐1,2,3,4‐tetrahydroacridines.
A short synthesis of the hexahydropyrido[4,3‐b]carbazole core structure for the synthesis of aspidosperma alkaloids
Authors: Ergun Yavuz
Published: March 2009

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A short synthesis of the hexahydropyrido[4,3‐b]carbazole derivative 8 which is important for the preparation of aspidosperma alkaloids was described. Construction of the tetracyclic structure was achieved via a short synthetic route and some new carbazolone derivatives (4, 5, 6 and 7) were synthesized.
Synthesis of new pentacyclic diquinothiazines
Authors: Nowak Małgorzata , Pluta Krystian , Suwińska Kinga , Straver Leo
Published: March 2009

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Reactions of 2,2′‐dichloro‐3,3′‐diquinolinyl sulfide 1 with ammonia derivatives and various primary alkylamines and arylamines proceeded as a thiazine ring closure to form linear annulated pentacyclic 6H‐diquinothiazine 2H and 6‐substituted derivatives 2 with alkyl, alkylaryl, aryl and heteroaryl substituents in moderate to good yields. Reaction with 2‐chloroethylamine did not stop at the formation of half‐mustard derivative 2k but ran to ethylenediquinothiazinium salt 11. 6H‐Diquinothiazine 2H was N‐alkylated and N‐arylated to give 6‐substituted derivatives 2. The crucial substrate 1 was obtained from other heteropentacenes 3 and 4 via 1,4‐dithiin ring opening and further transformations. X‐ray analysis of p‐nitrophenyldiquinothiazine 2i revealed unexpected planar thiazine ring.
2‐Vinyl quinazoline 3‐oxides; Preparation from acid induced cyclocondensation of 2‐acylaminoaryloximes
Authors: Heaney Frances , Lawless Elaine
Published: March 2009

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2‐Vinyl quinazoline 3‐oxides 6a, 6b and 15a are useful modular building blocks for the construction of a range of heterocycles with potential biological activity, from o‐[amidoalkenyl]aryloximes 5a, 5b and 14a, respectively, by cyclocondensation. Conjugate addition of EtOH or MeOH to the vinyl moiety of 6b is demonstrated.
1,3‐dipolar cycloaddition reaction: Synthesis and configuration of norcantharidin derivatives of substituted aromatic amine
Authors: Deng Liping , Hu Yongzhou
Published: March 2009

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A series of eighteen novel compounds that have potential pharmacological properties has been synthesized by 1,3‐dipolar cycloaddition reactions of 5,6‐dehydronorcantharidin derivatives of substituted aromatic amine with nitrile oxide. The synthesis was carried out following straightforward three‐step procedure described herein. IR, 1H nmr and ms, H‐H cosy and Noesy Cyclonoe, confirmed the structure of all products respectively. The biological evaluation of three series of norcantharidin analogues against HL60 cell has been screened.
Synthesis and antimalarial activity of 7‐benzylamino‐1‐isoquinolinamines
Authors: Gutteridge Clare E. , Hoffman Marshall M. , Bhattacharjee Apurba K. , Gerena Lucia
Published: March 2009

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Computer modelling suggests that 7‐benzylamino‐1‐isoquinolinamines should mediate antimalarial effects by a mechanism distinct from that employed by existing antimalarial drugs. A series of these compounds was prepared in seven synthetic steps, via reductive amination of 1,7‐isoquinolinediamine. In vitro efficacy testing of the novel compounds against Plasmodium falciparum revealed them to be potent antimalarial agents.
Synthesis and antimalarial activity of ethyl 3‐amino‐4‐oxo‐9‐(phenylsubstituted)thieno[2,3‐b]quinoline‐2‐carboxylate derivatives
Authors: Charris Jaime , Barazarte Arthur , Domínguez JosÉ , Lobo Gricela , Camacho JosÉ , Ferrer Rosa , Gamboa Neira , Rodrigues Juan , Capparelli Mario V.
Published: March 2009

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A series of thieno[2,3‐b]quinolone derivatives were synthesized and investigated for their abilities to inhibit β‐hematin formation, hemoglobin hydrolysis and in vivo for their efficacy in rodent Plasmodium berghei. Compound 3b was the most promising as inhibitor of hemoglobin hydrolysis, and its effects as inhibitor of β‐hematin formation was promising. When the aromatic ring was substituted in 2 (Me), in 3 (CF3) or in 2,4 (Cl) the inhibition of hemoglobin proteolysis was maximal (88%), the rest of compounds maintained a low inhibition. The most active compound to emerge in vitro and in murine studies, was 3b suggesting an antimalarial activity via multiple mechanisms.
New isochromans. 1. Synthesis and antimicrobial activity of 4‐substituted (±)‐1h‐spiro[benzo[c]pyran‐3(4H), 1′‐cyclohexane]‐1‐ones
Authors: Bogdanov Milen G. , Palamareva Mariana D. , Gocheva Blagovesta T. , Dimitrova Darina B.
Published: March 2009

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The reaction between homophthalic anhydride and cyclohexanone was examined both in the presence of DMAP or BF3·Et2O complex as a catalyst. The latter yielded (±)‐1‐oxo‐1H‐spiro[benzo[c]pyran‐3(4H), 1′‐cyclohexane]‐4‐carboxylic acid (3) in a higher yield (82 %). A series of new (±)‐4‐(N,N‐disubstituted‐1‐carbamoyl)‐1H‐spiro[benzo[c]pyran‐3(4H),1′‐cyclohexane]‐1‐ones (5a‐h) were synthesized from the parent acid 3 by a two‐step reaction. Differentiating microbial screening was performed for most of the synthesized compounds against twelve microorganisms belonging to different taxonomic groups. The spiro acid 3 was active against all bacterial strains with MIC ≥ 20 μg/ml against B. subtillis and P. vulgaris. E. coli was the most sensitive strain to the antibacterial effect of the tested compounds.
Synthesis, anti‐bacterial, anti‐asthmatic and anti‐diabetic activities of novel N‐substituted‐2‐(benzo[d]isoxazol‐3‐ylmethyl)‐1H‐benzimidazoles
Authors: Vaidya Sanjay Dashrath , Kumar Bobba Venkata Siva , Kumar Ramanatham Vinod , Bhise Umesh Nanasaheb , Mashelkar Uday Chandrakant
Published: March 2009

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Synthesis of a series of novel class of N‐substituted‐2‐(benzo[d]isoxazol‐3‐ylmethyl)‐1H‐benzimidazoles (4) by the condensation of o‐phenylenediamine (1) with benzo[d]isoxazol‐3‐yl‐acetic acid (2) and subsequent reactions with different types of electrophiles have been reported. Some compounds exhibited promising anti‐bacterial activity against Salmonella typhimurium, however poor activity against Staphylococcus aureus. The compound 4t was found to have high activity even at 1 μg/ml compared to Cephalexin against S. aureus. The biological activity against PDE‐IV for potential anti‐asthmatic effect and against DP‐IV and PTP‐1B for potential anti‐diabetic effects was disappointing.
A convenient one‐pot synthesis of new 3‐(4‐aryl‐5‐oxo‐5,6,7,8‐tetrahydro‐4H‐chromen‐2‐yl)‐2H‐chromen‐2‐ones
Authors: Rajeswar Rao V. , Ravinder Reddy V.
Published: March 2009

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Anhydrous zinc bromide catalysed reactions of arylidine‐3‐acetyl coumarins (1a‐c) and 5,6‐benzoanalogs of arylidine 3‐acetyl coumarins (4a,4b) with 1,3‐cyclohexanedione gives ‐(4‐aryl‐5‐oxo‐5,6,7,8‐tetrahydro‐4H‐chromen‐2yl)‐2H‐chromen‐2‐ones (3a, 3c) and 5,6‐benzoanalogs of 3‐(4‐aryl‐5‐oxo‐5,6,7,8‐tetrahydro‐4H‐chromen‐2yl)‐2H‐chromen‐2‐one (5a,5b). Under similar conditions arylidine‐3‐acetylcoumarins (1a, 1b,1d, 1e, 1f) and 5,6‐benzoanalog of arylidine 3‐acetyl coumarin (4b) react with 5,5‐dimethyl‐1,3‐cyclohexanedione (dimedone) yielding 3‐(4‐aryl‐7,7‐dimethyl‐5‐oxo‐5,6,7,8‐tetrahydro‐4H‐chromen‐2‐yl)‐2H‐chromen‐2‐ones (3d‐3h) and the 5,6‐benzoanalog of 3.(4‐aryl‐7,7‐dimethyl‐5‐oxo‐5,6,7,8‐tetrahydro‐4H‐chromen‐2‐yl)‐2H‐chromen‐2‐one (5c).
A facile one‐pot synthesis of 2‐amino‐4‐arylbenzo[h]quinoline‐3‐carbonitrile derivatives without catalyst
Authors: Tu Shujiang , Jia Runhong , Zhang Junyong , Zhang Yan , Jiang Bo
Published: March 2009

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A series of 2‐amino‐4‐arylbenzo[h]quinoline‐3‐carbonitrile derivatives were synthesized by one‐pot condensation of aromatic aldehyde, a‐naphthylamine and malononitrile in ethanol without catalyst. This multicomponent reaction has the notable advantages of short route, high yield and convenient operation.
A new bipyrrole coupling reaction
Authors: Nikitin Edward B. , Nelson Michael J. , Lightner David A.
Published: March 2009

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Pyrrole 8 was converted to 10 in 4 steps, and 10 was coupled directly to bipyrroles 1 in a Sonogashira reaction, respectively at the 3,3′ positions.
Selective nucleophilic substitution reactions in 2,4,6‐trisulfanyl‐substituted pyrimidine‐5‐carbonitriles by secondary amines
Authors: Drescher Simon , Ramsbeck Daniel , Dobner Bodo , Briel Detlef
Published: March 2009

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The highly functionalized heterocycles 6‐alkyl‐ respectively 6‐aralkylsulfanyl‐2,4‐bis‐(amidomethylsulfanyl) pyrimidine‐5‐carbonitriles react selective in the 2‐position with various secondary cyclic amines under mild conditions. The resulting pyrimidines were finally transformed into the corresponding thieno[2,3‐d]pyrimidine‐6‐carboxylic acid amides which afford the synthesis of selective substituted thienopyrimidines.
Three‐component, one‐pot synthesis of pyrimido[4,5‐b]‐quinoline and pyrido[2,3‐d]pyrimidine derivatives
Authors: Hassan N. A. , Hegab M. I. , Abdel‐Motti F. M. , Hebah S. H. A. , Abdel‐Megeid F. M. E. , Hashem A. I.
Published: March 2009

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Reaction of 6‐amino‐2‐methylthiouracil and 6‐amino‐1,3‐dimethyluracil with equimoler amounts of cyclic ketones or cyclic 1,3‐diketones and the appropriate aromatic aldehydes yielded regioselectivity a series of polycyclic pyrimido[4,5‐b]quinoline and pyrido[2,3‐d]pyrimidine derivatives in good yields.
Dimethylformamide dimethyl acetal in heterocyclic synthesis: Synthesis of polyfunctionally substituted pyridine derivatives as precursors to bicycles and polycycles
Authors: Abu‐Shanab Fathi A. , Hessen A. M. , Mousa S. A. S.
Published: March 2009

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Polysubstituted pyridines 11a,c and 12 were prepared by the reaction of benzoylacetone with dimethylformamide dimethyl acetal followed by treatment with cyanothioacetamide 9a, cyanoacetamide 9b and the anion of malononitrile dimmer 9c in dry DMF. When the reaction was carried out in ethanol as a solvent and piperidine as a base afforded 14a,b. Thienopyridines 16a,b were prepared by the reaction of pyridinethiones 11a and 14a with 2‐chloro‐N‐p‐tolyl‐acetamide (15). Further reaction of thienopyridines 16a,b with either DMFDMA or nitrous acid to gave 17a,b and 18a,b respectively. The reaction of pyridine derivative 11c with hydrazine and phenylhydrazine afforded the tricyclic compounds 19a,b.
Microwave solvent free regioselective 1,3 dipolar cycloaddition in the synthesis of 1,4 substituted [1,2,3]‐triazoles as amide bond isosteres
Authors: Perissutti Elisa , Frecentese Francesco , Fiorino Ferdinando , Severino Beatrice , Cirillo Donatella , Santagada Vincenzo , Caliendo Giuseppe
Published: March 2009

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1,3 Dipolar cycloaddition of Fmoc‐amino azides and acetylenic amides produces under solvent free irradiation a mixture of 1,4 or 1,5 substituted [1,2,3]‐triazoles. The presence of copper (I) iodide, plays a central role on regioselectivity. Four Fmoc‐amino azides characterized by different steric hindrance in side chains, and three different terminal alkynes, provided only the 1,4 substituted regioisomer under thermal microwave heating. Good yields, low consumption of organic solvents and short reaction times are the main aspects of our procedure. Reactions are compared to regioselective copper (I) catalysed solution synthesis performed at room temperature.
Synthesis of meso‐tetrakis(4‐chlorocoumarin‐3‐yl)porphyrins
Authors: Amaravathi M. , Rajitha B. , Rao M. Kanakalingeswara , Sitadevi P.
Published: March 2009

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meso‐Tetrakis(4‐chlorocoumarin‐3‐yl)porphyrins were prepared by condensation of corresponding 4‐chlorocoumarin‐3‐carboxaldehydes and pyrrole in the presence of trifluoro acetic acid (TFA) in dichloromethane followed by oxidation with 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ). These porphyrins exhibited the atropisomerism due to ortho substituent of meso aryl groups. The atropisomers of meso‐tetrakis(4‐chloro‐6‐methylcoumarin‐3‐yl)porphyrin were separated and identified by 1H‐nmr spectra. Zinc complexes of these porphyrins were synthesized and characterized by ms, 1H nmr, ir and uv‐vis spectra.
An efficient microwave‐assisted synthesis of 3,5‐unsubstituted 4‐substituted‐6‐aryl‐3,4‐dihydropyridin‐2(1H)‐ones derivatives
Authors: Tu Shujiang , Zhu Xiaotong , Shi Feng , Zhang Jinpeng , Zhang Yan
Published: March 2009

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Small libraries of 3,5‐unsubstituted 4‐substituted‐6‐aryl‐3,4‐dihydropyridin‐2(1H)‐ones derivatives were synthesized from the condensation‐products of aldehydes with Meldrum's acid, aromatic ketones and ammonium acetate using acetic acid as energy transferring‐agent under microwave irradiation without catalyst. This method has the advantages of excellent yields (65‐90%), short reaction time (5‐10 min) and being environmentally friendly. It aimed to provide new series of potential biologically active compounds for biomedical screening.
Regioselective synthesis of pentacyclic polyheterocycles: Sequential [3,3] sigmatropic rearrangement of 4‐(4′‐aryloxybut‐2′‐ynyloxy)‐1‐phenyl‐1,8‐naphthyridin‐2(1H)‐ones
Authors: Majumdar Krishna C. , Rafique‐ul‐Islam
Published: March 2009

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A number of 4‐aryloxymethyl‐6‐phenyl‐2H‐pyrano[3,2‐c][1,8]naphthyridin‐5(6H)‐ones (4a‐f) are regioselectively synthesized in 72‐78% yield by the Claisen rearrangement of 4‐(4′‐aryloxybut‐2′‐ynyloxy)‐1‐phenyl‐1,8‐naphthyridin‐2(1H)‐ones (3a‐f) in refluxing chlorobenzene for 4‐6 h. These products are then subjected to a second Claisen rearrangement catalyzed by anhydrous AlCl3 at room temperature for 2 h to give hitherto unreported pentacyclic heterocycles (5a‐f) in 78‐85% yield.
Studies with pyridazines and condensed pyridazines: Routes for synthesis of 3‐amino‐5‐aryl‐2,5‐dihydro‐pyridazine, 10aH‐pyridazino[1,6‐a]quinazoline and thieno[3,4‐d]pyridazinone
Authors: Aziz Suzan Ibrahim , Anwar Hany Fakhry , El‐Apasery Morsy Ahmed , Elnagdi Mohamed Hilmy
Published: March 2009

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Novel routes to 3‐aminopyridazines, 10aH‐pyridazino[1,6‐a]quinazoline and, thieno[3,4‐d]pyridazine utilizing the reaction of 2‐oxobutanal‐1‐arylhydrazones 3a,b with α,β‐unsaturated nitriles are described. Condensation of 3 with ethyl cyanoacetate afforded pyridazinones that reacted with sulphur yielding thienopyradazinone 10. Reaction of 10 with maleic anhydride and acrylonitrile afforded products of addition and hydrogen sulphide elimination. On other hand reacting 10 with enaminone and ethyl propionate afforded the product of addition of the amino function to activated double bond.
Synthesis and biological properties of 1,8‐naphthalimidebutylamines. Serotonin 5‐HT1Aand 5‐HT7binding data and pass‐assisted search
Authors: Kowalski Piotr , Kowalska Teresa , Bojarski Andrzej J. , Duszyńska Beata
Published: March 2009

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Syntheses of the N‐substituted butyl derivatives of 1,8‐naphthalimide (1‐8), containing various arylpiperazines, tetrahydroisoquinoline and methylhomopiperazine moieties attached at 4‐position of the butyl chain have been described. Biological activities were evaluatedin vitrofor their ability to bind to serotonin 5‐HT1Aand 5‐HT7receptors. Due to the structural similarity of derivatives1‐8to psychotropic agents, the pharmacological properties of target compounds were predicted using PASS program.