bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of hyperolactones A and C
Authors: Ueki Toshihiko , Doe Matsumi , Morimoto Yoshiki , Kinoshita Takamasa , Tanaka Rika , Yoshihara Kazuo
Published: March 2009

Hyperolactones A (1) and C (3) have been synthesized starting from (S)‐malic acid by a straightforward route. The unique spirolactone skeleton was efficiently constructed by one‐pot reaction as a key step. The absolute stereochemistry of hyperolactones was unambiguously established by this synthesis.
N‐bromosuccinimide reactions of some heterocycles in the presence or absence of water: An overview of ring versus side chain bromination for the synthesis of important brominated heterocyclic synthons
Authors: Goswami Shyamaprosad , Ghosh Kumaresh , Mukherjee Reshmi , Adak Avijit Kumar , Mahapatra Ajit Kumar
Published: March 2009

Reactions of various heterocycles 1–6 with N‐bromosuccinimide in the presence or absence of water have been studied for side chain versus ring bromination to afford some new and important heterocyclic synthons. Interestingly, the N‐bromosuccinimide reaction in the presence of perchloric acid, a new condition, affords exclusively the new dibromo aminopicoline 1f, which is not obtained by other presently studied methods.
New heterocycles with cycloamidine substructure and their ringtransformation reactions with acetylene dicarboxylic ester
Authors: Billot Thomas , Beckert Rainer , Döring Manfred , Wuckelt Jörg , Fehling Peer , Görls Helmar
Published: March 2009

The synthesis of pyrido[2,1‐c]‐1,2,4‐triazines 6, pyrido[1,2‐b]‐1,2,4‐triazines 7 and pyrido[1,2‐b]pyri‐dazines 8 respectively by cycloacylation of derivatives of pyridine with imidoylchlorides of type 2 is described. The heterocycles of type 6 as well as of type 7 can be ring‐transformed with dimethyl acetylenedicarboxylate. In contrast to pyrido[1,2‐a]pyrazines 1, a complex reaction including cleavage of the acetylene subunit takes place. Starting from compound 6a, the pyrrolo[2,3‐d]imidazole 11a could be isolated from a mixture of unidentified by‐products, whereas derivatives 7 gave nearly quantitatively the tricyclic products of type 12.
Synthesis and antimicrobial activity of 2‐substituted‐2,3‐dihydro‐5‐propoxy‐1H‐1,3,2‐benzodiazaphosphole 2‐Oxides
Authors: Venugopal M. , Reddy B. Sankar , Reddy C. Devendranath , Berlin K. D.
Published: March 2009

Several 2‐alkylcarbamato/thiocarbamato/aryloxy/trichloromethyl‐2,3‐dihydro‐5‐propoxy‐1H‐1,3,2‐benzodiazaphosphole 2‐oxides (4 and 6) were synthesised by reacting 4‐propoxy‐o‐phenylenediamine (1) with various N‐dichlorophosphinyl carbamates (3), aryl phosphorodichloridates (5a‐f) and trichloromethyl phosphonic dichloride (5g) in the presence of triethylamine at 45‐65 °C. Their ir, 1H, 13C, 31P nmr and mass spectral data are discussed. The compounds were screened for antifungal activity against Curvularia lunata and Aspergillus niger and for antibacterial activity against Bacillus subtilis and Escherichia coli. Most of these compounds exhibited moderate activity in the assays.
Facile synthesis of mono and dibenzo N,N'‐disubstituted diaza 18‐crown‐6 derivatives
Authors: Topal Giray , Demirel Nadir , Toğrul Mahmut , Turgut Yilmaz , Hoşgören Halil
Published: March 2009

This study represents a facile synthesis of building blocks (1–3) of crown ethers and amine precoursers (4a‐d). The study also involves synthesis of mono and dibenzo N, N‐disubstituted diaza 18‐crown‐6 derivatives with high yield without chromatographic purification and high vacuum distillation. The complex ability of host the ethers was evaluated in terms of structural modification.
Ru catalyzed cyclodimerization of bis(2‐thienyl)acetylene and bis(3‐thienyl)acetylene. Synthesis properties of 4,5,6‐tris(2‐thienyl)benzo(b)thiophene and 5,6,7‐tris(3‐thienyl)benzo[b]thiophene
Authors: Lu Ping , Li Jian , Weber William P. , Cai Guoping
Published: March 2009

Activated dihydridocarbonyltris(triphenylphosphine)ruthenium catalyzes the cyclodimerization of both bis(2‐thienyl)acetylene and bis(3‐thienyl)acetylene to yield, respectively, 4,5,6‐tris(2′‐thienyl)‐benzo[b]thiophene and 5,6,7‐tris(3′‐thienyl)benzo[b]thiophene. These fluoresce in the blue. Both undergo irreversible one electron oxidation at & sim1.1 mV versus Ag/Ag+ electrode, consistent with oxidation of the benzo[b]thiophene nuclei rather than the substituent thiophene rings.
Reaction of 2,5‐dimethylpyrroles with quinones. Synthesis of new pyrrolylquinones
Authors: Lion Dyes Claude , Baudry Richard , Hedayatullah Mir , Da Conceiçlato Louis , Genard Sylvie , Maignan Jean
Published: March 2009

The reaction of 1,4‐naphthoquinone (1) with 2,5‐dimethylpyrroles (7a‐7d) gives only 3‐(1,4‐naphtho‐quinonyl)‐2,5‐dimethylpyrroles. Extending the reaction to other quinones: 5‐hydroxy‐1,4‐naphthoquinone (2), 1,2‐naphthoquinone (3), quinoline‐5,8‐dione (4) and quinoxaline‐5,8‐dione (5), of which nothing was known, allows the synthesis of new pyrrolylquinones.
Thermal cyclization of 3‐azido‐2‐phenyl‐indan‐l‐one to 5h‐indeno[1,2‐b]indol‐10‐one
Authors: Stadlbauer Wolfgang , Fischer Michaela
Published: March 2009

3‐Azido‐2‐phenylindan‐1‐one (4), which was obtained from 3‐chloro‐2‐phenylindan‐1‐one (3), cyclizes on thermolysis to 5H‐indeno[1,2‐b]indol‐10‐one (5). Reaction of 3‐azido‐2‐phenylindan‐1‐one (4) with triphenylphosphane gives 2‐phenyl‐3‐(triphenylphosphoranylideneamino)‐indan‐1‐one (6), which can be hydrolyzed to 3‐amino‐2‐phenylindan‐1‐one (7). Attempts to perform a similar cyclization sequence with 3‐chloro‐2‐pyridylindan‐1‐ones failed.
Synthesis and characterization of some heterocyclic derivatives by cyclization of carbohydrate thiosemicarbazone ‐ part III
Authors: Alho M. A. Martins , D'Accorso N. B.
Published: March 2009

Synthesis of (3′R) 2‐acetamido‐4‐N‐acetyl‐3′‐spiro‐[1,2′:5′,6′‐di‐O‐isopropylidene‐α‐D‐glucofuranosyl]‐1,3,4‐thiadiazoline diastereomerically pure is described. We report the physical and spectroscopic characterization of the new heterocyclic compound as well as its immediate precursors. We discuss also the possibilities for cyclization and established the stereochemistry of the new stereogenic center.
Synthesis and characterization of 1‐methyl‐2,4,5‐trinitroimidazole (MTNI)
Authors: Cho Jin Rai , Kim Kwang Joo , Cho Soo Gyeong , Kim Jeong Kook
Published: March 2009

We have reinvestigated the synthesis of 1‐methyl‐2,4,5‐trinitroimidazole (MTNI; 1), and further characterized its physical properties. It is a promising candidate as an insensitive high explosive. Compound 1 was synthesized from the imidazole (2), via a 5‐step sequence of reactions, and subjected to various sensitivity tests for explosives. The structure of 1 was characterized by X‐ray diffraction. The crystal is orthorhombic; C4H3N5O6, M = 217.11, Z = 8, Pca21, a = 8.6183(6) Å, b = 17.7119(12) Å, c = 10.6873(7) Å, V = 1631.38(19) Å3, Dc = 1.768 g/cm3. The structure was refined to R = 0.0284 for 3201 independent reflections with I > 2σ(I). The molecular structures calculated by high levels of ab initio and density functional theories were in good agreement with those observed by X‐ray experiment. According to our preliminary sensitivity tests, 1 was characterized to be intermediate in sensitivity between RDX and TNT. The explosive performances were evaluated theoretically, and were found to be comparable to those of RDX. In addition, owing to its low melting point (82 °C), 1 is believed to be an excellent candidate for inclusion in melt‐castable explosives, and may lead to increased explosive power.
A synthetic pathway to obtain heterocyclic derivatives containing isoxazole and tetrazole rings joined by a carbohydrate tether
Authors: Esperón María F. Martinez , Fascio Mirta L. , D'Accorso N. B.
Published: March 2009

A synthetic route to obtain compounds with two different heterocycles, such as isoxazole and tetrazole rings, in the same molecule from carbohydrate derivatives using 1,3‐dipolar cycloaddition is described. The new compounds involved in this synthesis are physically and spectroscopically characterized.
Recent advancements in the homoallylamine chemistry
Authors: Puentes Cristian Ochoa , Kouznetsov Vladimir
Published: March 2009

New advances in preparation of homoallylamines are discussed. Novel syntheses of saturated nitrogen‐containing heterocycles from N‐substituted homoallylic amines are reviewed.
Synthesis and characterization of some N‐mannich bases of [1,2,3]triazoloquinolines
Authors: Ferlin Maria Grazia , Chiarelotto Gianfranco , Castagliuolo Ignazio
Published: March 2009

Some novel N‐Mannich bases of [1,2,3]‐triazolo[4,5‐f] and [4,5‐h]quinolines were synthesized following the classical experimental procedure for Mannich base preparation: triazoloquinoline with formaldehyde and secondary amine. Tricyclic nuclei were obtained starting from two protected isomeric amino‐quinolines, which were nitrated, reduced and diazotated. Two N‐anilinomethyltriazoloquinolines were also synthesized via the N‐hydroxymethyl intermediate.
Studies on the chemistry of thienoannelated O,N‐ and S,N‐containing heterocycles. 24 [1]. Synthesis of imidazo[1,5‐d]thieno[2,3‐b][1,4]‐thiazine derivatives as potential receptor ligands
Authors: Erker Thomas , Handler Norbert
Published: March 2009

A facile synthesis of the imidazo[1,5‐d]thieno[2,3‐b][1,4]thiazine ring system is described. Reaction of 6‐benzyl‐2,3‐dihydro‐1H‐thieno[2,3‐b][1,4]thiazine‐2‐one (1) with potassium tert‐butoxide and diethylchlorophosphate gave intermediate 2 which resulted in the disired ring system after adding the corresponding isocyanides and potassium tert‐butoxide.
N‐arylhexahydropyrimidines. Part 1. Synthesis and 1H NMR characterization of 1,3‐Di and 1,2,3‐trisubstituted derivatives
Authors: Perillo Isabel A. , García María B. , Bisceglia Juan Á. , Orelli Liliana R.
Published: March 2009

A series of N‐arylhexahydropyrimidines la‐1 were synthesized by condensation of N‐aryl‐N'‐alkyl‐ (or aryl)‐1,3‐propanediamines 2a‐h with aldehydes. Reactions with formaldehyde proceeded in hydroalcoholic solution, while condensation with aromatic aldehydes required in general the use of activated molecular sieves. 1H NMR spectra of compounds la‐1 were analyzed and the results correlated with their conforma‐tional features. Derivatives devoid of a 2‐substituent la‐g show fast ring reversal and N‐inversion. The presence of a 2‐aryl group shifts the ring reversal equilibrium towards conformations where the 2‐aryl substituent is equatorial. Differential assignment of axial and equatorial hydrogens in these compounds was made on the basis of coupling constants and chemical shift values. In compound 1k spectral data suggest the axial orientation of the N‐methyl group. Such findings were confirmed in the corresponding NOESY spectrum.
The synthesis and properties of new carbohydrate‐modified mesoionic thiazolo[3,2‐α]pyrimidine‐5,7‐dione acyclonucleosides
Authors: Stoelting Daniel T. , Mbagwu Godwin O. , Scott Tina , Long Michael , Sharpe Elsa L.
Published: March 2009

The synthesis of the first examples of Class II mesoionic thiazolopyrimidine acyclonucleosides (MTA) incorporating the 2,3‐dihydroxypropyl moiety as the sugar simulator is described. First, 2‐bromothiazole was reacted with excess 1‐amino‐2,3‐propanediol acetonide via an aromatic nucleophilic substitution reaction to yield 1‐(2‐thiazolylamino)‐2,3‐propanediol acetonide. This acetonide intermediate was condensed at 160° with substituted bis(2,4,6‐trichlorophenyl) malonic esters to form a series of protected acyclonucleosides termed anhydro‐(8‐((2,2‐dimethyl‐1,3‐dioxolan‐4‐yl)methyl)‐5‐hydroxy‐7‐oxothiazolo[3,2‐a]pyrimi‐dinium hydroxides) which differ in their 6‐position substituent. Deprotection of these acyclonucleosides using p‐toluenesulfonic acid catalyst in methanol at 65° yielded the desired Class II MTA, anhydro‐(8‐(2,3‐dihydroxypropyl)‐5‐hydroxy‐7‐oxothiazolo[3,2‐a]pyrimidinium hydroxides).
Synthesis of 3‐aryl‐5‐styryl‐2‐pyrazolines by the reaction of (E,E)‐cinnamylideneacetophenones with hydrazines and their oxidation into pyrazoles
Authors: LÉvai Albert , Patonay TamÁs , Silva Artur M. S. , Pinto Diana C. G. A. , Cavaleiro José A. S.
Published: March 2009

New 3‐aryl‐5‐styryl‐2‐pyrazolines have been synthesized by the reaction of (E,E)‐cinnamylideneace‐tophenones with hydrazines. These 2‐pyrazolines have also been converted into the corresponding pyrazoles by oxidation with chloranil. Structures of all new compounds have been elucidated by elemental analysis, mass spectrometry, ir and nmr spectroscopic measurements.
Novel syntheses of polysubstituted pyrroles and oxazoles by 1,3‐dipolar cycloaddition reactions of benzotriazole‐stabilized nitrile ylides
Authors: Katritzky Alan R. , Zhang Suoming , Wang Mingyi , Kolb Hartmuth C. , Steel Peter J.
Published: March 2009

1,3‐Dipolar cycloadditions of benzotriazole‐stabilized nitrile ylides with benzyl α,β‐unsaturated‐carboxy‐lates and aldehydes as dipolarophiles proceeded smoothly and efficiently to give polysubstituted pyrroles and oxazoles, respectively, in good yields.
Synthesis and molecular structure of novel 4‐aryloctahydropyrido‐[1,2‐c]pyrimidine derivatives
Authors: Herold Franciszek , Kleps Jerzy , Szczȩsna Beata , Anulewicz‐Ostrowska Romana
Published: March 2009

A series of new 4‐aryloctahydropyrido[1,2‐c]pyrimidine‐1,3‐diones 6a,b,d‐h and j were synthesized by intramolecular cyclization of α‐aryl‐α‐(1‐ethoxycarbonyl‐2‐piperidyl)‐acetamide derivatives 5a,b,d‐h and j. The structures of compounds were determined by 1H and 13C nmr spectroscopy. Nmr and X‐ray diffraction data indicate that the configuration at the C4, C4a stereocenters constitute RR and SS pair.
Recyclizations of 2‐aminobenzylimines and thioaroylhydrazones of N‐substituted N‐hydroxy‐3‐oxobutanamides
Authors: Zelenin Kirill N. , Lagoda Igor V. , Alekseyev Valeriy V. , Sinkkonen Jari , Pihlaja Kalevi , Shaikhutdinov Roustem A.
Published: March 2009

A universal scheme is proposed for the molecular design of heterocyclic recyclizations by replacing the exocyclic hydroxyl groups in exo‐trig‐ ring‐chain tautomeric molecules with substituted amines or hydrazines. The practical applicability of this approach is demonstrated by the condensations of 5‐hydroxy‐5‐methyl‐3‐isoxazolidinones with thioaroyl‐hydrazines and 2‐aminomethylaniline. The condensation products were studied by modern 1H, 13C and 15N NMR spectroscopic methods using three solvents: CDC13, DMSO[D6] and CD3CN. The solvent was found to have a strong effect to the relative amounts of the tautomers.
Synthesis of some new pyridazino cinnoline derivatives
Authors: Soliman A. M.
Published: March 2009

2,5‐Dibromo‐3,6‐(dihydrazino or diphenylhydrazino)‐1,4‐benzoquinone 1a,b reacts with active methyl‐ene reagents to give some new functionally substituted pyridazino cinnoline derivatives.
Synthesis and reactions of 6‐methylsulfanyl‐2,4‐dithioxo‐1,2,3,4‐tetrahydropyrimidin‐5‐carbonitrile
Authors: Briel Detlef , Franz Tanja , Dobner Bodo
Published: March 2009

The synthesis of 6‐methylsulfanyl‐2,4‐dithioxo‐1,2,3,4‐tetrahydropyrimidine‐5‐carbonitrile 4 is described. Compound 4 was reacted with various alkylants. The reaction with chloroacetic acid derivatives results in the formation of thieno[2,3‐d]pyrimidines 8. When methyl iodide was used 2,4,6‐tris(methylsul‐fanyl)pyrimidine‐5‐carbonitrile 5 was obtained. The substitution of the methylsulfanyl groups in compound 5 by several N‐nuclophiles leads to amino substituted pyrimidines.
Facile synthesis of model 1,4‐dihydro‐1H‐1,3,4‐benzotriazepin‐5‐ones
Authors: Abu Thaher Bassam A. , Zahra Jalal A. , El‐Abadelah Mustafa M.
Published: March 2009

2‐Aminobenzoic acid reacts readily, in the presence of triethylamine, with hydrazonoyl chlorides (5a‐c) (precursors of the reactive nitrile imine 1,3‐dipolar species) to afford high yields of the corresponding acyclic amidrazone adducts (6a‐c). The latter adducts undergo, in THF in presence of 1,1‐carbonyldiimida‐zole, smooth intramolecular cyclization involving the activated carboxyl and the NH‐ termini to deliver unequivocally the respective dihydro‐1,3,4‐benzotriazepin‐5‐ones (7a‐c).
2‐Chloro‐4,5‐dihydroimidazole, Part X. Revisiting route to N‐heteroarylimidazolidin‐2‐ones
Authors: Sa̧czewski Franciszek , Bulakowska Anita , Gdaniec Maria
Published: March 2009

The ureidation reactions of 2‐ and 4‐picoline N‐oxides with 2‐chloro‐4,5‐dihydroimidazole are described. A mechanism of novel thioureidation reaction of 4‐picoline N‐oxide with 2‐(4,5‐dihydro‐1H‐imidazol‐2‐ylthioxy)‐4,5‐dihydro‐1H‐imidazole is proposed. Structural assignment is confirmed by 1H and 13C nmr as well as by X‐ray crystallography.
Synthesis and structural characterisation of 4H‐1,3‐benzothiazine derivatives
Authors: Fodor Lajos , Bernáth Gábor , Sinkkonen Jari , Pihlaja Kalevi
Published: March 2009

The ring‐closure reactions of N‐arylthiomethylaroylamide derivatives (1a‐g) in the presence of phospho ‐rus oxychloride gave 2‐aryl‐4H‐1,3‐benzo‐thiazines (2a‐g). 2‐(3‐Chlorophenyl)‐6‐methyl‐4H‐1,3‐benzoth‐iazine (2b) was reduced with Zn to obtain the corresponding 2,3‐dihydro derivative (3b). Potassium permanganate oxidation of 2‐(4‐chlorophenyl)‐2,3‐diethoxy‐4H‐ (2e) and 2‐(2‐fluorophenyl)‐6,7‐diefhoxy‐4H‐1,3‐benzo‐thiazines (2g) gave the corresponding 4‐ones (4e,g). The reactions of 2‐(4‐chlorophenyl)‐6‐mefhyl‐4H‐1,3‐benzofhiazine (2c) with substituted acetyl chlorides led to linearly condensed ß‐lactams (5a,b). The structures of the compounds studied were confirmed by 1H and 13C NMR and by their characteristic mass spectrometric fragmentations.
Isolation of methyl (RS)‐1‐tert‐butoxycarbonyl‐3‐cyanomethyl‐1,2‐dihydro‐2‐oxo‐5H‐pyrrole‐5‐carboxylate, the key‐intermediate in base‐catalyzed formation of racemic products by 1,3‐dipolar cycloadditions to methyl (S)‐1‐tert‐butoxycarbonyl‐3‐[(E)‐cyanomethylidene]‐2‐pyrrolidinone‐5‐carboxylate
Authors: Škof Marko , Pirc Samo , Rečnik Simon , Svete Jurij , Stanovnik Branko , Golič Ljubo , Selič Lovro
Published: March 2009

Cycloadditions of various 1,3‐dipoles to methyl (S)‐1‐tert‐butoxycarbonyl‐3‐[(E)‐cyanomethylidene]‐2‐pyrrolidinone‐5‐carboxylate (9) were studied. Reactions of 9 with diazomethane (10) and 2,4,6‐trimethoxy‐benzonitrile oxide (11), carried out under neutral conditions, gave the corresponding optically active spiro compounds 16‐18 with low diastereoselectivity (20‐30% diastereomeric excess). On the other hand, reactions of 9 with nitrile oxide 11 and nitrile imines 14, 15, carried out in the presence of a base, afforded racemic pyrazolo and isoxazolo fused 2‐pyrrolidinones 21‐23 in 82‐86% diastereomeric excess. Optically active dipolarophile 9 was isomerized in the presence of basic alumina to give methyl (RS)‐1‐tert‐butoxy‐carbonyl‐3‐cyanomethyl‐1,2‐dihydro‐2‐oxo‐5H‐pyrrole‐5‐carboxylate (19). Treatment of the racemic dipolarophile 19 with dipoles 11 and 14, afforded fused 2‐pyrrolidinones 23 and 21. These observations support compound 19 as the key‐intermediate in the formation of racemic cycloadducts 21‐23.
Efficient photochemical synthesis of tricyclic keto‐indoles
Authors: Tietcheu Christèle , Garcia Christophe , Gardette Daniel , Dugat Denise , Gramain Jean‐Claude
Published: March 2009

Tricyclic keto‐indoles were synthesized by photocyclization of easily obtained enaminones in an electro‐cyclic photochemical reaction. The three methods reported were chosen according to the enaminone structure. The most general procedure using one‐step synthesis was carried out in a benzene‐methanol solution in the presence of sodium methylate. In the case of base sensitive substrates, the best method was photocyclization followed by oxidation. Besides, N‐unsubstituted indoles with a five‐membered ring were prepared by a photolysis reaction. All three methods are efficient and easy to perform.
Heterocyclization reaction of 2‐(2‐methylaziridin‐1‐yl)‐3‐ureidopyridines under appel's conditions
Authors: Lim Ji‐Sun , Lee Kee‐Jung
Published: March 2009

The reaction of 2‐(2‐methylaziridin‐1‐yl)‐3‐ureidopyridines12with triphenylphosphine, carbon tetra‐chloride, and triethylamine (Appel's conditions) led to the corresponding carbodiimides13, which underwent intramolecular cycloaddition reaction with aziridine under the reaction conditions to give the pyridine‐fused heterocycles, 2,3‐dihydro‐1H‐imidazo[2′,3′:2,3]imidazo[4,5‐b]pyridines16and 12,13‐dihydro‐5H‐1,3 ‐benzodiazepino [2′,3′:2,3] imidazo[4,5‐b]pyridines17.
Synthesis of new 1,2‐dihydrophthalazines
Authors: Lukács Gyula , Simig Gyula
Published: March 2009

New 6‐chloro‐ and 6,7‐dichloro‐4‐(4‐aminophenyl)‐2‐(N‐alkylcarbamoyl)‐1,2‐dihydrophthalazines (12,18) were synthesized starting from 6‐chloro‐ and 6,7‐dichloro‐4‐(4‐nitrophenyl)phthalazine (8). Routes to 1‐unsubstituted (12) and 1‐methyl (18) derivatives are different. Key intermediates 8 were prepared from 4‐chloro‐ and 3,4‐dichlorotoluene via ortho‐formylbenzophenone derivatives 7.
Synthesis of novel pyrido[3′,2′:5,6]thiopyrano[3,2‐b]indol‐5(6H)‐ones and 6H‐pyrido[3′,2′:5,6]thiopyrano[4,3‐b]quinolines, two new heterocyclic ring systems
Authors: Da Settimo Antonio , Marini Anna María , Primofiore Giampaolo , Da Settimo Federico , Salerno Silvia , Simorini Francesca , Pardi Gianluca , La Motta Concettina , Bertini Daniele
Published: March 2009

The synthesis of new pyrido[3′,2′:5,6]thiopyrano[3,2‐b]indol‐5(6H)‐ones was accomplished by the Fischer‐indole cyclization of some 2,3‐dihydro‐3‐phenylhydrazonothiopyrano[2,3‐b]pyridin‐4(4H)‐ones, obtained from the 2,3‐dihydro‐3‐hydroxymethylenethiopyrano[2,3‐b]pyridin‐4(4H)‐one, by the Japp‐Klingemann reaction.

6H‐Pyrido[3′,2′:5,6]thiopyrano[4,3‐b]quinolines were obtained by reaction of 2,3‐dihydrothiopyrano‐[2,3‐b]pyridin‐4(4H)‐ones with o‐aminobenzaldehyde or 5‐substituted isatins. The preparation of some derivatives, functionalized with an alkylamino‐substituted side chain, is also described.
An approach to novel fused triazole or tetrazole derivatives starting from benzimidazo[1,2‐a]quinazoline‐5(7H)‐one and 5,7‐dihydro‐5‐oxopyrido[3′,2′:5,6]pyrimido[1,2‐a]benzimidazole
Authors: Da Settimo Antonio , Primofiore Giampaolo , Da Settimo Federico , Pardi Gianluca , Simorini Francesca , Marini Anna Maria
Published: March 2009

The synthetic potential of the title compounds benzimidazo[1,2‐a]quinazoline‐5(7H)‐one 2a and 5,7‐dihydro‐5‐oxopyrido[3′,2′:5,6]pyrimido[1,2‐a]benzimidazole 2b for the construction of novel polyhetero‐cyclic frameworks is reported. Compounds 2a,b, by conversion into their thio analogues 3a,b, were used for the synthesis of tetrazole (5a,b) and triazole (7a,b) derivatives, as well as for an unexpected synthesis of tri‐azoles 8a,b, isomers of 7a,b, resulting from the occurrence of a Dimroth rearrangement.
Synthesis of pyrrolidine based natural or unnatural product derivatives (1): Application of efficient asymmetric induction of C‐2 position in polysubstituted pyrrolidines
Authors: Jeong Hyung Jae , Lee Ju Man , Kim Min Kyu , Lee Sang‐Gyeong
Published: March 2009

A novel method for synthesis of polysubstituted pyrrolidines, which possess a C‐2 stereocenter, was developed. The strategy involves Grignard addition to the succinimide, derived from L‐tartaric acid, followed by stereocontrolled triethylsilane promoted reduction of the resulting cyclic amidols.
Enaminones in heterocyclic synthesis: A new regioselective synthesis of 2,3,6‐trisubstituted pyridines, 6‐substituted‐3‐aroylpyridines and 1,3,5‐triaroylbenzenes
Authors: Al‐Saleh Balkis , Abdelkhalik Mervat Mohammed , Eltoukhy Afaf Mohammed , Elnagdi Mohammed Hilmy
Published: March 2009

1‐Substituted‐3‐dimethylaminopropenones 1a‐d reacted with acetylacetone and with ethyl acetoacetate to yield regioselectively 2,3,6‐trisubstituted pyridines. Refluxing 1a‐d in acetic acid/ammonium acetate resulted in the formation of 6‐substituted‐3‐aroylpyridines, whereas refluxing in acetic acid alone afforded 1,3,5‐triaroylbenzene.
Synthesis of zincic phthalocyanine derivative functionalized with four peripheral tetrathiafulvalene units
Authors: Hu Yingyu , Shen Yongjia
Published: March 2009

A zincic phthalocyanine (Pc) derivative functionalized with four peripheral substituted tetrathiafulvalene (TTF) units has been synthesized. The intermediates and target compound have been characterized by 1H‐nmr, 13C‐nmr, ms, EA, uv‐vis and mp. The molecular weight of H2Pc‐TTF4 can not be found in mass spectra. 1H‐nmr spectra and mp determination show both H2PC‐TTF4 and ZnPc‐TTF4 are isomer‐mixtures. Uv‐vis spectra indicate that the aggregation of H2PC‐TTF4 is solvent dependent and the introduction of Zn atom affects the solubility of the assembly.
Ultrasonic irradiation of the ullmann condensation: Application to the preparation of dioxolo, dioxino, cyclopent, and imidazolo anthranilic acid derivatives
Authors: Robin Maxime , Pique Valérie , Faure Robert , Galy Jean‐Pierre
Published: March 2009

The synthesis of N‐aryl anthranilic acid derivatives bearing dioxolo, dioxino, cyclopent, and imidazolo supplementary ring systems is reported. The Ullmann‐Goldberg condensation of the N‐aryl anthranilic acid is improved in yield and reaction time, compared to conventional heating; by ultrasonic irradiation.
Synthesis and biological evaluation of 9‐thia‐5,10‐dideazafolic acid
Authors: Wall Mark , Benkovic Stephen J.
Published: March 2009

The folate analogue, 9‐thia‐5,10‐dideazafolic acid (3b), was obtained in an efficient two‐step procedure in an overall yield of 60%. The previously unknown intermediate dimethyl‐thiocarbamic acid S‐(2‐amino‐3,4‐dihydo‐4‐oxo‐pyrido[2,3‐d]pyrimidin‐6‐yl) ester (5) was prepared via the condensation of 2,6‐diamino‐3H‐pyrimidin‐4‐one and S‐(2‐malonaldehyde)‐1,1,3,3‐tetramethylthiouronium bromide (4). Compound 5, in a one pot procedure, was deprotected using sodium hydroxide and then coupled to diethyl N‐[(4‐chloromethyl)benzoyl]‐L‐glutamate, followed by saponification of the ethyl esters to give the 9‐thia‐5,10‐dideazafolic acid (3b). Compound 3b was a potent inhibitor of human 5‐aminoimidazole‐4‐carboxamide ribonucleotide transformylase (Ki of 8 ± 5 μM) and showed no inhibition of human glycinamide ribonu‐cleotide transformylase at concentrations as high as 50 μM. Compound 3b was screened by the National Cancer Institute Developmental Therapeutics Program against 60 human tumors and was found to be active against a leukemia RPMI‐8226 cell line where the LC50 was 1 μM.
A convenient method for the preparation of highly substituted pyrimidines: Synthesis of tri‐ and tetra‐subsituted pyrimidines from 1,3‐dicarbonyl compounds and N,N,N‐tris‐(trimethylsilyl)amidines
Authors: Ghosh Usha , Katzenellenbogen John A.
Published: March 2009

A modification of the Pinner pyrimidine synthesis has been developed that utilizes trimethylsilyl amidines and results in greatly improved yield of highly substituted pyrimidines.
Preparation of substituted 1,3‐dihydro‐2H‐imidazo[4,5‐c]pyridin‐2‐ones
Authors: Bakke Jan M. , Gautun Hanna S. H. , Svensen Harald
Published: March 2009

A new synthetic route to 6‐substituted‐imidazo[4,5‐c]pyridin‐2‐ons from 4‐aminopyridine has been investigated. 4‐Aminopyridine protected as alkyl carbamates were nitrated with dinitrogen pentoxide to the corresponding methyl, i‐propyl and t‐butyl 3‐nitropyridin‐4‐yl carbamates (5a‐c) in 51‐63 % yields. Attempts to substitute these in the 6‐position by the ONSH and the VNS techniques succeeded with butyl‐amine and the t‐butyl carbamate 9. From the methyl or t‐butyl 3‐nitropyridin‐4‐yl carbamates 5a, 5c 1,3‐dihydro‐2H‐imidazo[4,5‐c]pyridin‐2‐one (1) was formed in 73 and 39 % yields, respectively. t‐Butyl 6‐N‐butylamin‐3‐aminopyridin‐4‐yl carbamate (6) gave 6‐butylamino‐1,3‐dihydro‐2H‐imidazo[4,5‐c]‐pyridin‐2‐one (7) in 53 % yield.
Synthesis of (+/‐) mappicine and mappicine ketone
Authors: Henegar Kevin E. , Baughman Ted A.
Published: March 2009

Mappicine and mappicine ketone are camptothecin analogs of interest as antiviral agents. A novel synthesis of these compounds is described using a Friedlander condensation. The requisite ketone is prepared via a regioselective ortho‐directed metallation/alkylation of a trisubstituted pyridine. This is condensed with N‐t‐butyloxycarbonyl‐o‐aminobenzaldehyde as a convenient, stable o‐aminobenzaldehyde equivalent in the Friedlander condensation.
A facile route for the synthesis of novel γ‐lactams
Authors: Kumar K. R. Ravi , Basappa  , Rangappa K. S. , Mallesha H.
Published: March 2009

A selective reduction and its subsequent cyclisation of novel isoxazolidines into γ‐lactams have been examined in presence of Raney ‐ nickel catalyst.
1,2,3‐ and 1,2,4‐triazolium salts, pyrazoles, and quinoxalines from diarylnitrilimines and isocyanides: A study of the scope
Authors: Moderhack Dietrich , Daoud Ali
Published: March 2009

Formation of the four title compounds has been found to be strongly dependent on substituents: 1,2,3‐Triazolium salts 6 do not arise from nitrilimines 2 that have an electron‐acceptor attached to either the C‐ or the N‐phenyl group. Likewise tert‐butyl and aryl isocyanides do not afford this class of compounds; from the former isocyanide, dequaternization products 7 are obtained instead, whereas from the latter 1,2,4‐triazolium salts 11 are formed. Compounds 11 with tert‐butyl group at the ring are unstable too, giving rise to triazoles 13. Pyrazole formation (analogues of 14) is completely suppressed when both tert‐butyl and aryl isocyanides are used, whereas access to this ring system works best with see‐alkyl isocyanides (the influence of substituents of 2 being almost negligible in this case). Formation of quinoxalines 23 which arise from intermediary 1,2‐diazets 22 by ring expansion is much favoured on employment of 2 that bears a donator substituent at the N‐phenyl group, and under this premise ring closure to 22 is virtually independent on the nature of the isocyanide. Formation of 23 is not observed with 2 having acceptor groups.
The effect of intramolecular‐hydrogen bonds in the synthesis of novel imidates from a 13‐membered dioxadithia crown ether diester
Authors: Karaböcek Serdar , Degirmencioglu Ismail , Karaböcek Nevin , Er Mustafa , Serbest Kerim
Published: March 2009

The synthesis and structural properties of three novel imidates, 11,13‐bis‐(2‐amino‐ethylimino)‐1,10‐dioxa‐4,7‐dithiacyclotridecane (2), 11,13‐bis‐(3‐aminopropylimino)‐1,10‐dioxa‐4,7‐dithiacyclotridecane, (3) and 2,11‐dioxa‐5,8‐dithia‐13,16,19,22‐tetraazabicyclo[10.10.1]tricosa‐1(22),12‐diene, (4) have been described. These compounds were synthesized by treating 1,10‐dioxa‐4,7‐dithiacyclotridecane‐11,13‐diester (1) with the appropriate diamine under N2 and their structures have been characterised by elemental analyses, 1H‐ and 13C‐nmr, ir, and mass spectral studies. Elemental analyses and spectroscopic data support the proposed imidate structures. In addition, total energy and heat of formation (Figure 2) calculated for imidates 2a‐4a and 2b‐4b by the semiempirical AM1 calculations have shown that imidates 2b‐4b having intramolecular hydrogen bonds are more stable (5‐10 kcal/mol) than compounds 2a‐4a.
Novel ‘quinolone’ metal complexes: Synthesis and spectroscopic studies of mg(II), zn(II) and ba(II) complexes with N‐methyl (or NH)‐3‐acetyl‐4‐hydroxy quinolin‐2‐one ligands
Authors: Athanasellis Giorgos , Gavrielatos Efstathios , Igglessi‐Markopoulou Olga , Markopoulos John
Published: March 2009

The complexation between N‐methyl‐3‐acetyl‐4‐hydroxyquinolin‐2‐one (NMeQuin) and N‐H‐3‐acetyl‐4‐hydroxy quinolin‐2‐one (NHQuin) with MgCl2, ZnCl2 and BaCl2 has been accomplished. The structure of the resulting complexes 1–5 has been elucidated through elemental analyses, FT‐IR and 1H/13C NMR Spectroscopy and Mass Spectrometry. The spectroscopic data show complexes of the general formula Mg2(OH)L3(H2O)z and ML2(H2O)Z where: M = Zn(II) and Ba(II), L = NMeQuin, NHQuin and z = 2, 4.
2‐(4‐methylpyridin‐2‐yl)‐1H‐benzimidazole derivatives. Part II, lH nmr characterization
Authors: Barni Ermanno , Barolo Claudia , Quagliotto Pierluigi , Savarino Piero , Viscardi Guido , Marabello Domenica
Published: March 2009

A selected series of 2‐(4‐methylpyridin‐2‐yl)‐1H‐benzimidazole derivatives, bases and cyclic mono‐ and bis‐salts, were synthesized. Complete '1H nmr characterization is reported. Ambiguous assignments were solved using 1H‐1H NOESY analysis. Significant ir and 1H nmr data are presented concerning: i) tautomeric equilibrium of imidazole hydrogen; ii) hydrogen bonds; iii) conformational inversion of partially saturated rings.
Synthesis of 3‐Ω‐amino‐2‐thiohydantoins
Authors: Ryczek Józef
Published: March 2009

In the reaction of ethyl isothiocyanatoacetate with diamines, followed by cyclization of the intermediate product, 3‐monosubstituted thiohydantoins have been obtained. It was found that the reaction course depends on the purity of the isothiocyanate used and also, in the case of dialkylaminoamines, the self‐cyclization occurs. Besides the dialkylamino derivatives of 3‐monosubstituted 2‐thiohydantoins also new monoalkylamino, amino and heterocyclic derivatives were synthesized. The aryldiazonium derivative of 3‐monosubstituted 2‐thiohydantoin yielded both respective phenol derivative after hydrolysis and the product of coupling with 2‐naphthol.
Nickel boride mediated reductive desulfurization of 2‐thioxo‐4(3H)‐quinazolinones: A new synthesis of quinazolin‐4(3H)‐ones and 2,3‐dihydro‐4(1H)‐quinazolinones
Authors: Khurana Jitender M. , Kukreja Gagan
Published: March 2009

A novel one‐pot approach for the synthesis of aryl substituted quinazolin‐4(3H)‐ones and 2,3‐dihydro‐4(1H)‐quinazolinones has been reported based on the reductive desulfurization of 3‐aryl‐2‐thioxo‐4(3H)‐quinazolinones with nickel boride in dry methanol at ambient temperature.
Transition metal free reductive dimerization of nitrogen containing barbituric acid benzylidenes
Authors: Jursic Branko S. , Stevens Edwin D.
Published: March 2009

Through the NMR monitoring of the reactive intermediates in the condensation of barbituric acid with nitrogen containing heterocyclic 2‐carboxaldehydes, a synthetic procedure was developed for the preparation of each of the intermediates. The simple high yield procedure for the preparation of the reductive dimer from corresponding barbituric acid benzylidenes was developed, although we were not able to elucidate the source of the reduction. The structure of the dimer was confirmed by X‐ray analysis.
2‐Arylhydrazono‐3‐oxopropanals in heterocyclic synthesis: Synthesis of arylazopyrazole, arylazoisoxazole and dialkylpyridazine‐5,6‐dicarboxylate derivatives. New one‐step synthesis of arylazopyrimidines
Authors: Al‐Shiekh Mariam A. , Salah El‐Din Abdellatif M. , Hafez Ebtisam A. , Elnagdi Mohamed H.
Published: March 2009

A novel synthesis of arylpyrazole, isoxazole, dialkyl 1,6‐dihydropyridazine 5,6‐dicarboxylate derivatives and a new one‐step synthesis of azolopyrimidines under microwave‐assisted conditions are reported.
Use of some aryl and heteroaryl nitrilimines and nitrones in the synthesis of spiroheterocycles
Authors: Jedlovská Eva , Fišera Lubor
Published: March 2009

1,3‐Dipolar cycloadditions of C‐(5‐nitro‐2‐furyl)‐N‐methyl nitrilimine (2a), C‐(5‐nitro‐2‐furyl)‐N‐phenyl nitrilimine (2b), C‐4‐nitrophenyl‐N‐methyl nitrilimine (2c) and C,N‐diphenyl nitrilimine (2d) with 1‐R‐substituted 3,3‐methylene‐5,5‐dimethylpyrrolidin‐2‐ones (1a‐d) where R is H, acetyl, 1,1‐dimethylethoxycarbonyl and 1‐methylethenyl proceed with complete regioselectivity in good yields to afford 1,3,7‐trisubstituted‐6‐oxo‐8,8‐dimethyl‐1,2,7‐triazaspiro[4,4]non‐2‐enes (5a‐g) exclusively. Cycloaddition of C‐(5‐nitro‐2‐furyl)‐N‐phenylnitrone (3b) to the exocyclic double bond of the dipolarophile 1a proceeds to 2‐phenyl‐3‐(5‐nitro‐2‐furyl)‐6‐oxo‐8,8‐dimethyl‐1‐oxa‐2,7‐diazaspiro[4,4]nonane (7) with complete regio‐ and stereoselectivity.
Ring transformations of heterocyclic compounds. XXIV. 1′,2′,5′,6′‐Tetrahydro‐4′H‐spiro[cyclohexa‐2,4‐diene‐1,2′‐pyrrolo[3,2,1‐ij]quinoline] and 1,2,4,5,6,7‐hexahydrospiro[azepino[3,2,1‐hi]indole‐2,1′‐cyclohexa[2,4]diene] – Two new spiro[cyclohexadiene‐azaheterocycles] easily accessible by pyrylium ring transformation
Authors: Zimmermann Thomas
Published: March 2009

The ring transformation of 2,4,6‐triarylpyrylium salts 1 with 2‐methyleneindolines of the type 3 in which the nitrogen atom is connected with the ortho‐carbon of the benzene ring by a (CH2)n chain is studied. Whereas the reaction of the pyrylium salts 1 with the 2‐methylene‐1,2,4,5‐tetrahydropyrrolo[3,2,1‐hi]indole 3a (n = 2), generated in situ from the 4‐methyl‐2,5‐dihydro‐1H‐pyrrolo[3,2,1‐hi]indolium perchlorate 2a, failed, the salts 1 react with the 2‐methylene‐1,2,5,6‐tetrahydro‐4H‐pyrrolo[3,2,1‐ij]quinolines 3b,c (n = 3) and the 2‐methylene‐1,2,4,5,6,7‐hexahydroazepino[3,2,1‐hi]indole 3d (n = 4), obtained in situ from the corresponding 2‐methyl‐1,4,5,6‐tetrahydropyrrolo[3,2,1‐if]lquinolinium perchlorates 2b,c and the 2‐methyl‐4,5,6,7‐tetrahydro‐1H‐azepmo[3,2,1‐hi]indolium perchlorate 2d, in the presence of triethylamine/acetic acid in boiling ethanol by a 2,5‐[C4+C2] transformation in high yield and diastereoselectivity to give the 1′,2′,5′,6′‐tetrahydro‐4′H‐spiro[cyclohexa‐2,4‐diene‐1,2′‐pyrrolo[3,2,1‐ij]quinolines] 5 and the 1,2,4,5,6,7‐hexahydrospiro[azepino[3,2,1‐hi]indole‐2,1′‐cyclohexa[2,4]dienes] 6, respectively. The influence of the length of the (CH2)n chain in 3 on the product formation and the diastereoselectivity can be explained by differences of the steric strain in the spiro compounds.
An exception of eschweiler‐clarke methylation: Cyclocondensation of α‐amino amides with formaldehyde and formic acid
Authors: Chen Fu‐Lin , Sung Kuangsen
Published: March 2009

An exception of Eschweiler‐Clarke methylation was found for α‐amino amides. The α‐amino amides on treatment with formaldehyde and formic acid produce cyclocondensation products, imidazolidin‐4‐ones, but N‐methylation process becomes important when three substituents of the α‐amino amides are very bulky. On the other hand, N‐methylation is the only product for Eschweiler‐Clarke methylation of the α‐amino amides with N,N‐disubstituted amide.
Routes to N‐vinyl‐nitroimidazoles and N‐vinyl‐deazapurines
Authors: Clayton Russell , Ramsden Christopher A.
Published: March 2009

The preparations of 4‐ and 5‐nitro‐1‐vinylimidazole (2 and 7) are described. Selective reduction of the nitro group using Fe/dil.HCl is achieved for the 4‐nitro derivative but this is not effective when ethoxymethylenemalononitrile is used to trap the amine. For 5‐nitroimidazole studies the N‐vinyl substituent is kept masked as a 2‐chloroethyl group, which remains unchanged during catalytic reduction of the nitro function (Pd/C), and is revealed by HCl elimination at a later stage. In this way, the 1‐deazapurine 13 and the tricyclic derivative 14 have been prepared.
Synthesis of 1‐(4‐thiazolyl)azulenes: Reactions of bromoacetyl‐substituted azulenes with thioamides, thioureas, and thiosemicarbazones
Authors: Takao Hiromi , Wang Dao‐Lin , Kikuchi Shigeru , Imafuku Kimiaki
Published: March 2009

1‐(Bromoacetyl)‐3‐methylazulene (1a) and methyl 3‐(bromoacetyl)azulene‐1‐carboxylate (1b) reacted with thioamides 3a,b and thioureas 3c,d in boiling ethanol to give the corresponding (4‐thiazolyl)azulenes 4a‐d and 5a‐d in good yields, respectively. The reactions of dibromoacetyl‐substituted azulene (2) also gave (4‐thiazolyl) azulenes 5a‐d in lower yields and the azulene 2 was recovered. By heating compounds 5a‐d in 100% phosphoric acid, the ester group was eliminated to yield 1‐(4‐thiazolyl)azulenes 6a‐d. Compounds 1a,b reacted with thiosemicarbazones 7a‐f to afford [(2‐alkylidenehydrazino)thiazol‐4‐yl]azulenes 8a‐f and 9a‐f in moderate to high yields via their hydromides.
Facile cleavage of Narylsulfonyl bond of N‐arylsulfonylimidazolidinone with magnesium in methanol
Authors: Nadir Upender K. , Vijaya Krishna R.
Published: March 2009

Cleavage of Narylsulfonyl bond in N‐arylsulfonylimidazolidinones is best carried out selectively with magnesium in methanol.
Isolation and characterization of a novel tetrahydro‐[2,2′]bipyrrolyl dimer as an impurity from a knorr reaction
Authors: Thompson Alison , Alattar Yousef , Beshara Cory S. , Burley Rodney K. , Stanley Cameron T. , Robertson Katherine N.
Published: March 2009

A novel dimer, tetraethyl 2,2′,3,3′‐tetramethyl‐1,1′,2,2′‐tetrahydro‐4H,4′H‐2,2′‐bipyrrolyl‐5,5,5′,5′‐tetracarboxylate, has been isolated as an impurity (0.4% yield) from a Knorr reaction for the synthesis of ethyl 3,5‐dimethylpyrrole‐2‐carboxylate from 2,4‐pentanedione and diethyl oximinomalonate in a dissolving zinc reduction. The solid‐state structure of this novel dimer was determined by X‐ray crystallography. Knorr reactions typically rely upon the requisite pyrrole being the only water‐insoluble crystalline material present in the reaction mixture, and so work‐up and purification procedures for Knorr reactions should be monitored carefully given the water‐insolubility of this dimer. Investigations regarding mechanistic implications and reductive dimerization are underway.
A new synthesis of 1,2,3,5‐tetrahydroimidazo[2,3‐b]‐[1,3]benzodiazocines
Authors: In Cho Hyun , Lee Seung Won , Lee Kee‐Jung
Published: March 2009

A new synthesis of 6‐carbomethoxy‐1,2,3,5‐tetrahydroirnidazo[2,3‐b][1,3]benzodiazocines 13 by the intramolecular cycloaddition reaction of methyl 2‐(1‐aziridinylmethyl)‐3‐(2‐ureidophenyl)propenoates 10 under Appel's dehydration conditions is described. The latter were readily obtained from 2‐nitrobenzalde‐hyde with methyl acrylate through the Baylis‐Hillman reaction.
Diels‐alder reaction of 1‐methyl‐3,6,8‐trinitro‐2‐quinolone
Authors: Asahara Motoki , Nagamatsu Moriaki , Tohda Yasuo , Nishiwaki Nagatoshi , Ariga Masahiro
Published: March 2009

1‐Methyl‐3,6,8‐trinitro‐2‐quinolone (1) behaved as the dienophile in Diels‐Alder reactions with dienes. When cyclopentadiene was used, cycloadduct 4 was obtained, which was then aromatized on treatment with triethylamine. In the reaction of 1 with hydrazone of 2‐butenal, phenanthridine derivative 7 was produced.
Hydrogen/deuterium exchange mass spectrometry identifies two highly protected regions in recombinant full‐length prion protein amyloid fibrils
Authors: Nazabal Alexis , Hornemann Simone , Aguzzi Adriano , Zenobi Renato
Published: March 2009

Understanding the structural basis that distinguishes the amyloid form of the prion protein from its monomeric homologue is of crucial importance to elucidate the mechanism of the lethal diseases related to this protein. Recently, an in vitro conversion system was established which reproduces the transition of recombinant prion protein PrP(23–230) from its native α‐helical rich form into an aggregated amyloid β‐sheet rich form with physicochemical properties reminiscent to those of the disease‐related isoform of the prion protein, PrPSc. To study the tertiary and quaternary structural organization within recombinant amyloid fibrils from mouse, mPrP(23–231)βf; bovine, bPrP(23–230)βf; and elk, ePrP(23–230)βf; we utilized hydrogen/deuterium (H/D) exchange analyzed by matrix‐assisted laser desorption/ionization (MALDI) and nano‐electrospray (nano‐ESI) mass spectrometry. No significant differences were found by measuring the deuterium exchange kinetics of the aggregated fibrillar forms for mPrP(23–231)βf, bPrP(23–230)βf and ePrP(23–230)βf, indicating a similar overall structural organization of the fibrils from all three species. Next, we characterized the solvent accessibility for the soluble and fibrillar forms of the mouse prion protein by hydrogen exchange, pepsin proteolysis and nano‐ESI ion trap mass spectrometry analysis. In its amyloid form, two highly protected regions of mPrP(23–231) comprising residues [24–98] and [182–212] were identified. The residues between the two highly protected stretches were found to be more solvent exposed, but less than in the soluble protein, and might therefore rather form part of a fibrillar interface. Copyright © 2009 John Wiley & Sons, Ltd.
Simplified method for determining cadmium concentrations in rice foliage and soil by using a biosensor kit with immunochromatography
Authors: Abe Kaoru , Sakurai Yasuhiro , Okuyama Akira , Sasaki Kazuhiro , Tawarada Kei
Published: March 2009

BACKGROUND: The behavior of cadmium in ecosystems needs to be monitored because of the human toxicity of this heavy metal. The need recently arose for a simple and quick on‐site test for trace levels of Cd in food and environmental samples. In response, an immunochromatographic assay kit for detecting Cd was manufactured by Kansai Electric Power Co. of Japan. This kit uses the antigen–antibody complex reaction between the Cd–EDTA complex and an anti‐Cd–EDTA antibody and shows the results in terms of the degree of color developed on a test paper. We previously reported the successful use of this kit to determine Cd concentrations in brown rice. Here, we applied the kit to the determination of Cd concentrations in rice foliage and soil.

RESULTS: Cadmium in rice foliage was not extracted successfully by the method used for brown rice. However, it was successfully extracted by 0.1 mol L−1 HCl solution at a rice foliage:HCl ratio of 1:20, and coexisting metals were removed sufficiently by the column treatment. The Cd concentrations determined by immunochromatographic assay were well correlated with the values obtained by acid decomposition and inductively coupled plasma mass spectrometry. The 0.1 mol L−1 HCl‐extractable Cd concentration in soil was also determined successfully with the kit.

CONCLUSION: Approximate Cd concentrations in rice plants and 0.1 mol L−1 HCl‐extractable Cd concentrations in soil can be monitored easily and quickly by this method at locations where facilities for acid digestion and precision analysis are not available. Copyright © 2009 Society of Chemical Industry
Novel alcoholic beverages: production of spirits and liqueurs using maceration of melon fruits in melon distillates
Authors: Hernández Gómez Luis Fernando , Úbeda Juan , Arévalo‐Villena María , Briones Ana
Published: March 2009

BACKGROUND:The object of this study was to macerate melon fruit (Cucumis melo, L.) in melon distillate to produce a liqueur that would possess the sensory attributes of the fruit. Chemical and sensory analysis was performed on the different spirits.

RESULTS:Spirits macerated with melon pieces, seeds and placenta showed double the sugar concentration compared to spirits macerated with seeds and placenta only. Concentrations of esters and higher alcohols were also higher in the first macerated. Neithern‐butanol nor ethyl butyrate were detected in any of the batches. The sensory analysis results (rank‐order tests) did not disclose any significant differences among the spirit batches although maceration with seeds and placenta conferred a golden colour to the spirit that is popular in commercial products. All the batches can be grouped close together in the greenish yellow quadrant, though in the region closer to yellow. Liqueurs contained higher quantities of ethyl acetate than the macerated spirits.

CONCLUSIONS:Macerated spirit with seeds and placenta was the most adequate for production on account of its deeper colour, its suitability for filtration, and its typical melon aroma, as well as its lower production costs. The acceptability of melon liqueur was similar to other spirits tasted. Copyright © 2009 Society of Chemical Industry