bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of integrated back‐propagation network and self organizing map for flood forecasting
Authors: Yang Chao‐Chung , Chen Chang‐Shian
Published: March 2009

Much of the nonlinearity and uncertainty regarding the flood process is because hydrologic data required for estimation are often tremendously difficult to obtain. This study employed a back‐propagation network (BPN) as the main structure in flood forecasting to learn and to demonstrate the sophisticated nonlinear mapping relationship. However, a deterministic BPN model implies high uncertainty and poor consistency for verification work even when the learning performance is satisfactory for flood forecasting. Therefore, a novel procedure was proposed in this investigation which integrates linear transfer function (LTF) and self‐organizing map (SOM) to efficiently determine the intervals of weights and biases of a flood forecasting neural network to avoid the above problems. A SOM network with classification ability was applied to the solutions and parameters of the BPN model in the learning stage, to classify the network parameter rules and to obtain the winning parameters. The outcomes from the previous stage were then used as the ranges of the parameters in the recall stage. Finally, a case study was carried out in Wu‐Shi basin to demonstrate the effectiveness of the proposal. Copyright © 2009 John Wiley & Sons, Ltd.
Hydrologic characteristics of lake‐ and stream‐side riparian wetted margins in the McMurdo Dry Valleys, Antarctica
Authors: Northcott Melissa L. , Gooseff Michael N. , Barrett John E. , Zeglin Lydia H. , Takacs‐Vesbach Cristina D. , Humphrey John
Published: March 2009

Water is a limiting factor for life in the McMurdo Dry Valleys (MDV), Antarctica. The active layer (seasonally thawed soil overlying permafrost) accommodates dynamic hydrological and biological processes for 10–16 weeks per year. Wetted margins (visually wetted areas with high moisture content) adjacent to lakes and streams are potential locations of great importance in the MDV because of the regular presence of liquid water, compared with the rest of the landscape where liquid water is rare. At 11 plots (four adjacent to lakes, seven adjacent to streams), soil particle size distribution, soil electrical conductivity, soil water content and isotopic signature, width of the wetted margin, and active layer thaw depth were characterised to determine how these gradients influence physicochemical properties that determine microbial habitat and biogeochemical cycling. Sediments were generally coarse‐grained in wetted margins adjacent to both lakes and streams. Wetted margins ranged from 1·04 to 11·01 m in average length and were found to be longer at lakeside sites than streamside. Average thaw depths ranged from 0·12 to 0·85 m, and were found to be deepest under lake margins. Lake margins also had much higher soil electrical conductivity, steeper topographic gradients, but more gradual soil moisture gradients than stream margins. Patterns of soil water δ18O and δD distribution indicate capillary action and evaporation from wetted margins; margin pore waters generally demonstrated isotopic enrichment with distance from the shore, indicating evaporation of soil water. Lake margin pore waters were significantly more negative in DXS (DXS = δD‐8δ18O) than streamside pore waters, indicating a longer history of evaporation there. Differences between lake and stream margins can be explained by the more consistent availability of water to lake margins than stream margins. Differences in margin characteristics between lakes and streams have important consequences for the microbial habitat of these margins and their functional role in biogeochemical cycling at these terrestrial–aquatic interfaces. Copyright © 2009 John Wiley & Sons, Ltd.
Water productivity of irrigated wheat and maize in the Karkheh River basin of Iran
Authors: Qureshi A. S. , Oweis T. , Karimi P. , Porehemmat J.
Published: March 2009

The Karkheh River Basin (KRB) is the third largest and most productive river basin of Iran. The major agricultural issue of the KRB is low water use efficiencies. Farmers' irrigation practices are aimed at maximizing crop production through excessive use of irrigation water resulting in huge water losses. As the opportunities for water resources development in the KRB are very limited, improving the productivity of existing water resources is the most attractive option to produce more food for the increasing population. This paper analyses water productivity of irrigated wheat and maize in the KRB. The results reveal that farmers having access to groundwater tend to apply higher irrigation amounts. Relatively higher crop yields in irrigated areas are also linked to higher nitrogen use, which might create serious problems of groundwater contamination in the future. Due to excessive use of groundwater and fertilizer, production costs have increased, resulting in low gross margins (farm incomes). The study suggests that an increase in charges for surface water use and removal of subsidies on electricity will discourage excessive use of water for agriculture. Furthermore, farmers should be trained to optimize irrigation water and fertilizer application in order to save scarce water resources and reduce production costs and increase farm returns. These steps are of great importance for ensuring sustainability of irrigated agriculture and to alleviate poverty in rural areas of the KRB. Copyright © 2009 John Wiley & Sons, Ltd.
Synthesis of 1,3,4‐thiadiazol‐2‐ylacetic acid derivatives
Authors: Saito Toshinori , Saheki Norio , Hatanaka Minoru , Ishimaru Toshiyasu
Published: March 2009

1,3,4‐Thiadiazol‐2‐ylacetic acids 4 were prepared by lithiation of 2‐methyl‐1,3,4‐thiadiazoles 1, followed by treatment with carbon dioxide. Diethyl 1,3,4‐thiadiazol‐2‐ylmalonates 6 were prepared by nucleophilic displacement reaction of the corresponding bromides 5 with diethyl malonate. Introduction of the amino group at the a‐position of 4 or 6 was carried out via oximation or bromination to give the amino ester 9 or 4. Attempts to prepare DL‐α‐amino‐1,3,4‐thiadiazol‐2‐ylacetic acids from 9 or 4 were unsuccessful because the amino acids were decarboxylated too rapidly to be isolated in the free form.
Nuclear magnetic resonance and stereochemistry of vincamone
Authors: Chimirri A. , Grasso S. , Fenech G. , Monforte P.
Published: March 2009

The stereochemistry in solution of vincamone was deduced by proton magnetic resonance using the paramagnetic shifts reagent Eu(fod)3. The lanthanide induced shift computer simulation suggests that, at room temperature, the indole group is nearly planar, the rings C and E assume the envelope conformation with N‐4 and C‐16 as flaps, the ring D is in the chair one and the ethyl side chain prefers a trans position with respect to C‐15.
Indazoles and dihydrophthalizines from N‐phenylhydrazidoyl chlorides
Authors: Baiocchi Leandro , Giannangeli Marilena
Published: March 2009

The action of polyphosphoric acid on some N‐phenylhydrazidoyl chlorides has been studied. Indazoles, di‐hydrophthalazines or Hoffmann‐Martius rearranged products were obtained depending on the particular substrate employed.
Pseudo‐nucléosides dérivés des pyrrolo[2, 3‐d]pyrimidines. Synthèse et activité biologique
Authors: Legraverend Michel , Bisagni Emile , Lhoste Jean‐Marc , Anker Daniel , Pacheco Henri
Published: March 2009

Une nouvelle série de pseudonucléosides a été obtenue par condensation de différents amino‐pentopyrannoses sur une dichloro‐4, 6 acétonyl‐5 pyrimidine. La cyclisation en pyrrolo[2, 3‐d]pyrimidine conduit ainsi en une seule étape, à de nouveaux analogues de la Tubercidine. Certains d'entre eux présentent une activité contre le virus de la vaccine et le virus sindbis.
The structure of a 1,3‐oxazonine derivative obtained by photochemical addition of 6‐cyanophenanthridine N‐oxide and 2,3‐dimethyl‐2‐butene
Authors: Oberti R. , Albini A. , Fasani E.
Published: March 2009

The crystal structure of 5, 6‐dihydro‐5, 5, 6, 6‐tetramethyl‐8‐cyanodibenzo[df][1, 3]oxazonine, obtained from the photochemical addition of 6‐cyanophenanthridine N‐oxide and 2, 3‐dimethyl‐2‐butene, is described.
Beckmann rearrangement of 3‐aza‐a‐homo‐4α‐androsten‐4,17‐dione oxime and 3‐oxo‐13α‐amino‐13,17‐seco‐4‐androsten‐17‐oic 13,17‐lactam oxime
Authors: Camoutsis Charalabos , Catsoulacos Panayotis
Published: March 2009

Rearrangements of 3‐aza‐A‐homo‐4α‐androsten‐4, 17‐dione oxime produced a mixture of the normal lactam product and the product of a “second order” cleavage, an unsaturated nitrile. The lactam 3, 17α‐di‐aza‐A, D‐bishomoandrost‐4α‐ene‐4, 17‐dione was also obtained from the rearrangement of the syn‐3‐oxo‐13α‐amino‐13, 17‐seco‐4‐androsten‐17‐oic‐13, 17‐lactam oxime. The resolution of syn‐ and anti‐isomers of VIII was effected by column chromatography and their structure was determined by spectral data.
Fused s‐triazino heterocycles. X. Displacement reactions of 7,9‐dibromo‐2‐tribromomethyl‐5‐trichloromethyl‐1,3,4,6,9b‐pentaazaphenalene and 7,9‐dibromo‐2,5‐bis(tribromomethyl)‐ 1,3,4,6,9b‐pentaazaphenalene
Authors: Shaw John T. , Starkey Kenneth D. , Pelliccione David J. , Barnhart Sharon L.
Published: March 2009

The preparation of 7, 9‐dibromo‐2‐tribromomethyl‐5‐trichloromethyl‐1, 3, 4, 6, 9b‐pentaazaphenalene (1c) and 7, 9‐dibromo‐2, 5‐bis(tribromomethyl)‐1, 3, 4, 6, 9b‐pentaazaphenalene (1d) is described. Reaction of 1c with various nucleophiles converted it to the corresponding 7, 9‐dibromo‐2, 5‐bis‐substituted derivatives, the tri‐halomethyl groups serving as leaving groups. Displacement, first of one tribromomethyl group on 1d by pyrrolidine, and then by various nucleophiles on the remaining tribromomethyl group led to several mixed 2, 5‐disubstituted derivatives.
The reaction of amines with isoflavones. I. Formation of phenolic pyrimidines
Authors: Oluwadiya J. O.
Published: March 2009

The reaction of isoflavones with guanidine carbonate in xylene at reflux gave 2‐aminophenolic pyrimidines.
Mass Spectral fragmentation patterns of heterocycles. V . Electron impact promoted mass spectral fragmentation of indolo[1,7‐ab][1]benzazepine and Some of its Derivatives
Authors: Vishwakarma L. C. , Hallberg A. , Martin A. R.
Published: March 2009

The fragmentation patterns of 1,2,6,7‐tetrahydroindolo[1,7‐ab][l]benzazepin‐1‐one (1), 6,7‐dihydroindolo‐[1,7‐ab][l]benzazepine (2) and indolo[1,7‐ab][1]benzazepine (3) on electron impact have been examined. Loss of carbon monoxide to form the base peak at m/e 207 and loss of CHO radical to give m/e 206 consititute the major fragmentation pathways for 1. The moleclar ions (M+) are abundant for each of the compounds; observed as the second most intense peak for 1 (85% relative intensity) and the base peaks for 2 and 3. The spectrum of 2 is characterized by intense M‐1 and M‐2 ions and by the presence of a M‐15 ion (m/e 204) of moderate intensity (11.4%). In all other respects the spectra of 2 and 3 are strikingly similar. The M‐15 ion from 2, assigned the heteroaromatic pyrroloacridinium structure, is also formed in the spectrum of 1. A second heteroaromatic ion at m/e 191, common to the spectra of 1, 2 and 3, is believed to have the pyrrolocarbazol‐ium structure. Metastable ion transitions and exact mass measurements support most of the proposed fragmentation pathways and structural assignments.
Réactions de cyclisation de pentynyl‐2 pyrimidones‐4
Authors: Rougeot Etienne , Moskowitz Henri , Miocque Marcel
Published: March 2009

Les amidines acétyléniques HC≡C‐CH2)n‐C(=NH)NH2 condensées avec des esters β‐cétoniques, permettent d'accéder à des pyrimidones portant une chaîne acétylénique en 2. Le chauffage de ces composés entraîne deux types de cyclisation. La cyclisation par attaque nucléophile de l'azote amidé sur la triple liaison est très minoritaire. Une cyclo‐addition mettant en jeu la triple liaison et un système azadiénique, formant un inter‐médiaire tricyclique peu stable et dont on isole les produits de rétrocyclisation, constitue la voie principale.
On the syntheses of thiophene analogs of practolol and “reversed” practolol
Authors: Casarrubio J. Luis , Conde Santiago , Corral Carlos , Lissavetzky Jaime
Published: March 2009

The synthesis of the thiophene analogs of the cardio‐selective β‐adrenergic blocking agents Practolol and “reversed” Practolol has been attempted starting from 2‐acetyl‐5‐bromothiophene. Although this synthesis worked for the second compound it was not possible to obtain the first one. From this and other results of this paper it can be deduced that the thiophene analog of Practolol must be an unstable compound.
A 13C‐NMR assignment study of a series of 2,3,4,5‐tetrahydro‐1‐methyl‐1H‐1,5‐benzodiazepine‐2,4‐diones
Authors: Aversa Maria Chiara , Ferlazzo Alida , Giannetto Placido
Published: March 2009

The natural abundance 13C‐nmr spectra of a series of 2,3,4,5‐tetrahydro‐1‐methyl‐1H‐1,5‐benzodiazepine‐2,4‐diones have been recorded: two of these compounds, clobazam and triflubazam, are clinically used as psychotherapeutic agents. The assignments of the various resonances have been made by chemical shift arguments, by the analysis of the fine splittings caused by one bond and long range couplings, and also by comparison with model compounds.
Pyridinethiones. VIII. The aldol and wittig condensations of 3‐formyl‐2(1H)‐pyridones, ‐thiones and ‐selones. Preparation of new cyanopyridones
Authors: Michael Maged Aziz , Becher Jan , Winckelmann Ib
Published: March 2009

Condensations of 1‐substituted‐3‐formyl‐2(1H)‐pyridones, ‐thiones and ‐selones with methyl ketones such as acetophenone give the corresponding chalcones in high yields. Geometry at the vinyl hydrogens is E. These chalcones can be cyclized with ethyl cyanoacetate in the presence of ammonium acetate to form new 3‐cyano‐2(1H)‐pyridones. An effective “one‐pot” preparation is worked out and an intermediate from the cyclization reaction is isolated. Via the Wittig reaction it is possible to prepare condensation products from 1‐substituted‐3‐formyl‐2(1H)‐pyridinethiones and ‐selones with mainly Z geometry at the vinyl hydrogens.
One‐pot synthesis and structure of 10‐heteroarylphenothiazines
Authors: Jovanovic Misa V. , Biehl Edward R.
Published: March 2009

Novel 10‐heteroarylphenothiazine compounds were prepared in high yields by Ullmann coupling of the appropriate iodoheterocycle, prepared in situ, with a series of phenothiazines. The 13C nmr analysis of titled compounds predicts geometries which are in excellent agreement with available x‐ray crystal structure data. The results also indicate significant π‐interaction between the electron‐rich phenothiazine ring and the π‐deficient heterocycles.
Base‐promoted reaction of a hydrazonyl chloride with 1‐phenylsulphonylpropyne
Authors: Bruché Luca , Zecchi Gaetano
Published: March 2009

Treatment of methyl 2‐chloro‐2‐phenylhydrazonoacetate (1) with 1‐phenylsulphonylpropyne (3) in the presence of triethylamine gives pyrazole derivatives due to cycloadditions of a nitrile imine intermediate with 3 and with its rearranged product phenylsulphonylallene (4).
The oxidative cyclization of n‐phenyl‐3‐methylthiopropylamines to form N‐phenyl‐s‐methylisothiazolidinium salts
Authors: Swank Darrell W. , Lambeth David O.
Published: March 2009

A series of N‐phenyl‐3‐methylthiopropylamine hydrochlorides were prepared by reacting a series of anilines with methional and sodium cyanoborohydride. These were cyclized upon oxidation by N‐chloro‐succinimide to the corresponding N‐phenyl‐S‐methylisothiazolidinium derivatives which were isolated as the tetraphenylborate salts. Compounds successfully prepared included the m‐methyl, p‐methyl, m‐methoxy, and p‐methoxyphenyl derivatives.
Study of hydantoin. III . Mass spectrometric behaviour in the electron impact of 2‐imino‐4‐thiazolidinone derivatives
Authors: Kwon Byoung M. , Park Jeen Woo
Published: March 2009

The mass spectral decomposition modes of a series of 2‐imino‐4‐thiazolidinone derivatives are reported and discussed. The fragmentation patterns and mechanisms postulated have been confirmed by the analysis of the MIKE spectra and using DADI technique and the effects of heteroatoms and substituents on the MIKE spectrum of these compounds are compared with that of 3‐substituted hydantoins.
4‐Azapteridines. 2. spectral, chromatographic, and X‐Ray crystallographic studies concerning the mode of covalent addition to the pyrazino[2,3‐e]‐as‐triazine ring system
Authors: Tzeng Cherng‐Chyi , Rychlewska Urszula , Hodgson Derek J. , Panzica Raymond P.
Published: March 2009

The first examples of the unknown pyrazino[2,3‐e]‐as‐triazine ring system, that is, the 6,7‐dihydroxy‐5,6,7,8‐tetrahydropyrazino[2,3‐e]‐as‐triazines, have been prepared by ring closure of selected 5,6‐diamino‐as‐triazines with 40% aqueous glyoxal. These 4‐azapteridines experience a novel exchange process with alcohols at the C(7)‐position. When dissolved in alcohol and stirred at room temperature, the 7‐alkoxy, 6‐hydroxy analogues are formed and isolated. In fact, during ring closure, if alcohols are used as the solvent, only the latter compounds are obtained. Initially, cyclization of the ortho‐diamino‐as‐triazines with glyoxal proceeds in a stereoselective manner giving rise to both the cis and trans adducts. A single‐crystal X‐ray diffraction study has determined the predominant and most stable adduct to be the trans (R,R or S,S) isomer. Spectroscopy (nmr) has verified the intermediacy of the cis adduct, but because of the aforementioned exchange process only the trans isomer is isolated. The site of exchange on these σ‐adducts has been rigorously established as C(7). A plausible reaction mechanism by which this exchange process occurs is presented.
4‐(Trinitromethyl)tetrahydro‐2‐furanol and 4‐(fluorodinitromethyl)tetrahydro‐2‐furanol via lactone reduction with borane. The preparation of cis/trans‐2‐polynitroalkoxy‐4‐polynitromethyltetrahydrofurans
Authors: Sitzmann Michael E. , Gilligan William H.
Published: March 2009

Normally borane reduces lactones too rapidly to allow the isolation of intermediates but 4‐(trinitromethyl)‐tetrahydro‐2‐furanol and 4‐(fluorodinitromethyl)tetrahydro‐2‐furanol are isolated in 72 and 36% yield from the reduction of 4‐hydroxy‐3‐(trinitromethyl)butyric acid, γ‐lactone and 4‐hydroxy‐3‐(fluorodinitromethyl)‐butyric acid, γ‐lactone with borane‐tetrahydrofuran complex. The preparation of 2‐polynitroalkoxy‐4‐polynitromethyltetrahydrofurans from the 2‐furanols is described.
Polycyclic N‐hetero compounds. XX. Synthesis of 11,13,15‐triazasteroid with an alkyl group in the d‐ring and an investigation of its antidepressive activity
Authors: Hirota Takashi , Kawanishi Keiko , Sasaki Kenji , Namba Tetsuto , Iwadoh Akimasa , Hayakawa Shohei
Published: March 2009

11,13,15‐Triazasteroidal skeleton with an alkyl group in the D‐ring was synthesized and it was screened for antidepressive activity. Compounds VIIId and XIIa exhibited antireserpine action.
Preparation and properties of electron donor acceptor complexes of the compounds having capto‐dative substituents
Authors: Sugimoto Akira , Kotani Takeshi , Tsujimoto Junko , Yoneda Shigeo
Published: March 2009

In order to examine the “capto‐dative” substitution‐effect on the electrical conductivity, five compounds which have capto‐dative substituents were prepared. Electron withdrawing (capto) group was nitro‐ or cyano‐substituted phenyl and electron donating (dative) one was 5‐methyl‐5,10‐dihydrophenazinyl moiety. The character of intramolecular electron donor acceptor complex of the five compounds were demonstrated by their uv spectra. Electron donor acceptor complexes of them with tetracyanoquinodimethane were prepared and their electrical resistivities were measured.
Gas phase reactivity of cation radicals and protonated species from isomeric C4H8S thioethers
Authors: Paradisi C. , Visentini A. , Traldi P.
Published: March 2009

Four isomeric thioethers, 2,3‐dimethylthiirane (1), 2‐methylthietane (2), tetrahydrothiophene (3), and allyl methyl thioether (4), have been subjected to mass spectrometric analysis in the gas phase, under electron impact (El) and chemical ionization (CI) conditions. The metastable molecular ions M+′ generated from 1‐4 under EI (70 eV) conditions give distinct patterns of unimolecular fragmentation, thus indicating that isomer interconversion reactions are slower than dissociation (a possible exception, to some extent, is the case of [M2]+′ and [M2]+′). The change of the relative intensities of some prominent peaks with increasing ion lifetime (decomposition within the ion source, the first, and the second field‐free regions of the mass spectrometer) is pointed out. Metastable [MH]+ ions, generated from 1‐4 in chemical ionization experiments with CH4, all eliminate H2 and H2S, although in different relative proportions. In addition to these processes protonated 4 also undergoes loss of C2H4 and C3H6, likely from a C‐protonated structure.
1, 3‐dipolar cycloaddition of diazomethane to azolopyridazines. The synthesis of 8‐methyl‐8H‐ and 9‐methyl‐9H‐pyrazolo[3, 4‐d]‐s‐triazolo[4, 3‐b]pyridazine and 1‐methyl‐1H‐ and 2‐methyl‐2H‐imidazo[1, 2‐b]pyrazolo[3, 4‐b]pyridazine derivatives
Authors: Merslavič Marjo , Petrič Andrej , Stanovnik Branko , Tišler Miha
Published: March 2009

The transformations of 7‐methyl‐7H‐ and 8‐methyl‐8H‐pyrazolo[4, 3‐d]tetrazolo[1, 5‐b]pyridazines 1, 2, 9 and 10 into 8‐methyl‐8H‐ and 9‐methyl‐9H‐pyrazolo[3, 4‐H]‐s‐triazolo[4, 3‐b]pyridazines 7 and 8, and 1‐methyl‐1H‐and 2‐methyl‐2H‐imidazo[1, 2‐b]pyrazolo[3, 4‐d]pyridazines 13 and 14 are described.
The synthesis of derivatives of new tetracyclic heterocyclic systems pyrazolo‐bis‐azolopyridazines
Authors: Merslavič Marjo , Stanovnik Branko , Tišler Miha
Published: March 2009

The synthesis of new tetracyclic systems and new stable tautomers of known systems 11H‐ 13 and 10H‐imidazo[1, 2‐b]pyrazolo[4, 3‐d]‐s‐triazolo[3, 4‐f]pyridazine 16, 9H‐pyrazolo[3, 4‐d]bis‐s‐triazolo[4, 3‐6:5′,1‐f]‐pyridazine 15, 10H‐pyrazolo[3, 4‐d]bis‐s‐triazolo[4, 3‐b:3′,4′‐f]pyridazine 17, and 10H‐pyrazolo[4, 3‐d)bis‐s‐triazolo[4, 3‐6:5′,1′‐f]pvridazine 18 is described.
A new fused heterocyclic system: 6H‐pyrazolo[3, 4‐c][1, 2, 5]thiadiazine 2, 2‐dioxide
Authors: Vicentini C. B. , Veronese A. C. , Poli T. , Guarneri M. , Giori P. , Ferretti V.
Published: March 2009

A base‐promoted cyclodehydration of 4‐nitroso‐5‐alkylsulfonylamidopyrazoles 3 afforded 6H‐pyrazolo‐[3, 4‐c][1, 2, 5]thiadiazine 2, 2‐dioxide (4). The structure of 4 was confirmed through X‐ray analysis.
FAB‐Induced deprotonation, elimination and decomposition of 1,3‐dithiolane S‐oxides
Authors: Bortolini O. , Traldi P.
Published: March 2009

The gas‐phase unimolecular decomposition of [M‐H]− of 1,3‐dithiolane S‐oxides has been studied using Fast Atom Bombardment (FAB) for anion generation. A comparison with the reactivity in solution is made and some differences or similarities with the chemistry in the gas‐phase are discussed. The decomposition pathways of the molecules under investigation are function of the substituents.
Polycyclic N‐hetero compounds. XXXII Synthesis and antidepressive evaluation of B‐homo‐11,13,15‐triazasteroids and their precursors
Authors: Hirota Takashi , Sasaki Kenji , Ieno Katsuhiro , Sekiya Yuhki , Nakayama Taiji
Published: March 2009

Synthesis of 4‐(2‐hydroxyethylamino)‐6,7‐dihydro‐5H‐benzo[6,7]cyclohepta[1,2‐d]pyrimidine derivatives V and their cyclized products, B‐homo‐11,13,15‐triazasteroidal compounds VI and VII, are described. These products were screened to evaluate the antidepressive activity.
An activated trifluoromethyl group as a new synthon for 4,5‐dihydro‐1H‐imidazole and 1,4,5,6‐tetrahydropyrimidine systems
Authors: Wydra Roman L. , Patterson Steven E. , Strekowski Lucjan
Published: March 2009

Treatment of 4‐(trifluoromethyl)benzenamine 1a and 2‐(trifluoromethyl)benzamine 1b with lithium 2‐aminoethylamide gives 2‐(4‐aminophenyl)‐4,5‐dihydro‐1H‐imidazole 3a and 2‐(2‐aminophenyl)‐4,5‐dihydro‐1H‐imidazole 3b, respectively. Similar reactions of 1a and 1b with lithium 3‐aminopropylamide produce the respective 2‐(aminophenyl)‐1,4,5,6‐tetrahydropyrimidines 4a and 4b. 3‐(Trifluoromethyl)benzenamine 1c is recovered unchanged from analogous mixtures. The mechanism is discussed.
5‐Heteroaryl‐2‐thiophenecarboxylic acids: Oxazoles and oxadiazoles
Authors: Goddard Carl J.
Published: March 2009

The synthesis of novel thiophene‐2‐carboxylic acids bearing alkyl and aryl‐substituted oxazole and oxadiazole rings is reported. Sequential functionalization of the key precursor, 5‐formyl‐2‐thiophenecarboxylic acid furnished the intermediate carboxylic acid esters which were converted into desired acids by basic cleavage.
1,3‐Dipolar cycle‐addition of 2‐diazoalkanes to pyridazin‐3(2H)‐one derivatives. The formation of 3H‐pyrazolo[3,4‐d]pyridazin‐4(5H)‐one and 3H‐pyrazolo[3,4‐d]pyridazin‐7(6H)‐one derivatives
Authors: Štimac Anton , Stanovnik Branko , Tišler Miha
Published: March 2009

1,3‐Dipolar cycloadditions of diazoalkanes to pyridazin‐3(2H)‐ones 1–7 and pyridazin‐3(2H)‐thiones 8 and 9 are regioselective producing 3H‐pyrazolo[3,4‐d]pyridazin‐4(5H)‐ones 15–19, 27–29 and 34–38 as the major products. In some instances, the isomeric 3H‐pyrazolo[3,4‐d]pyridazin‐7(6H)‐ones, such as 20 and 23 were isolated as the minor products. From 3 and 6 the primary 3a,7a‐dihydro cycloadducts 25 and 26, and rearranged 1,2‐dihydro intermediate 31 were isolated. From 10 and 1‐diazoindane the isomeric exo‐ and endospiro products 39 and 40 were formed.
Substituent effect on oxidative cyclization of aldehyde thiosemicarbazones with ferric chloride
Authors: Noto Renato , Buccheri Francesco , Cusmano Giuseppe , Gruttadauria Michelangelo , Werber Giuseppe
Published: March 2009

The reactivity of aldehyde thiosemicarbazones 1 with ferric chloride solutions was examined. When compounds 1 are not substituted on the N‐2 nitrogen atom formation of 1,3,4‐thiadiazole 3 heterocyclic ring was observed. In contrast 1,2,4‐triazoline 4 and/or 1,3,4‐thiadiazoline 5 heterocyclic rings were afforded when N‐2 nitrogen atom carried a methyl or a phenyl group. The reaction mechanism is also discussed.
Complete assignment of the 1H and 13C NMR Spectra of 11,12‐Dimethoxy[1]benzothieno[3,2‐a]‐4,7‐phenanthroline and its 8‐Chloro Analogue: Concerted Use of Two‐Dimensional NMR Techniques
Authors: Musmar M. J. , Castle Raymond N.
Published: March 2009

The 1H and 13C nmr spectra of 11,12‐dimethoxy[1]benzothieno[3,2‐a]‐4,7‐phenanthroline and its 8‐chloro precursor were totally assigned using a combination of two‐dimensional nmr techniques. After correlation of the majority of the proton signals by a COSY spectrum and one‐bond heteronuclear correlation, the full assignment of the 1H and 13C nmr spectra of the novel heterocyclic compounds required the application of long‐range CH coupling information particularly for quaternary carbon resonance assignments and the orientations of individual spin systems relative to one another. Key long‐range heteronuclear couplings in both compounds served to confirm the one‐bond heteronuclear correlations. Unequivocal interpretation of the spectral data leads to the complete assignments of the resonances.
Fused pyrimidines. 5. Methylated pyrimido[4,5‐d]pyrimidines
Authors: Delia Thomas J. , Baumann Markus
Published: March 2009

The Mannich reaction has been applied to pyrimidines possessing activating groups at positions 2, 4, and 6 and that have a methyl group attached at a ring nitrogen atom. The corresponding tetrahydropyrimido[4,5‐d]pyrimidines were obtained. In one case there was a possibility of isomer formation. Chemical reactivity was not successful in determining the structure but through an nmr program called INAPT, a version of INEPT, we were able to assign the structure as that of 6.
Rearrangements of pyrrole and indole substituted enol esters of cyclohexane‐1,3‐dione
Authors: Oliver James E. , Lusby William R. , Waters Rolland M.
Published: March 2009

Enol esters 3a and 3b, from cyclohexane‐1,3‐dione and pyrrole‐2‐carbonyl chloride and indole‐2‐carbonyl chloride, respectively, rearranged in the presence of triethylamine to the enamino acids 7 and 12. In the presence of cyanide, 3b, also underwent the expected rearrangement to 4b, whereas only 7 was formed from 3a. Treatment of 7 with mercuric acetate in hot acetic acid resulted in decarboxylation and aromatization to phenol 9.
Hydrogenolysis of 1‐aminopyrazoles: Synthesis of primary and secondary alkylamines
Authors: Adembri G. , Camparini A. , Ponticelli F. , Scotton M.
Published: March 2009

The tautomerizable N‐aminopyrazolone 9, the O‐methyl 1 and N‐methyl derivatives 4 were condensed with carbonyl compounds to give the alkenylaminopyrazoles 12, 2a‐g and 5c, which, under mild conditions, were hydrogenated to the corresponding alkylamino derivatives. The subsequent hydrogenation of the latter ones gave different results according to the structure of the starting material. The 5‐methoxy‐1‐alkylamino‐pyrazoles 3a‐g yielded the 5‐methoxypyrazole 15 and the corresponding primary amines in good yields. On the contrary, N‐methyl‐1‐alkylaminopyrazolone‐5 6c gave 1‐alkylpyrazolone‐3 8.
The synthesis of a potential anti‐cancer agent containing the caffeine and 1,2,4‐benzotriazine moieties
Authors: Parrick John , Mehta Lina K. , Hodgkiss Richard J.
Published: March 2009

The potential anti‐cancer agent 6 has been synthesised from 4‐(4‐chlorobutoxy)‐2‐nitroaniline, 15b by the conversion of the nitroaniline to the benzotriazine N‐oxide 16. Theophylline has been reacted with 16 to give the N‐oxide 9 and this has been oxidised to the required N,N'‐dioxide, 6. The compound 6 has been found to be ineffective as a radiosensitizer.
Deoxydative thiation of 3‐substituted pyridine N‐oxides with 4‐methoxytoluene‐α‐thiol: A divergent route to pyridinethiols
Authors: Sato Nobuhiro , Nagano Eiichi
Published: March 2009

Synthesis of 3‐substituted 2‐pyridinethiols was achieved by thiation of pyridine N‐oxides with 4‐methoxytoluene‐α‐thiol in the presence of diethylcarbamoyl chloride followed by cleavage of the resulting sulfides. The ease of substitution was shown to be affected by nucleophilicity of the N‐oxide oxygen. Addition of zinc bromide to the reaction, a need for triethylamine, decreased most of the yield for thiation products but the formation of 3‐methoxy‐2‐methoxybenzylthiopyridine was only improved. A plausible mechanism of the substitution, particularly β‐thiation to the N‐oxide function, is discussed compared with the regiochemistry observed in the reaction with diethoxyphosphoryl chloride instead of diethylcarbamoyl chloride. The debenzylation to pyridinethiol was also found to be dependent on the electron‐density in the pyridine ring.
Furopyridines. XIII. Reaction of 2‐methylfuro[2,3‐b]‐, ‐[3,2‐b]‐, ‐[2,3‐c]‐ and ‐[3,2‐c]pyridines with lithium diisopropylamide
Authors: Shiotani Shunsaku
Published: March 2009

Lithiation of 2‐methylfuro[2,3‐b]‐ 1a, ‐[2,3‐c]‐ 1c and ‐[3,2‐c]pyridine 1d with lithium diisopropylamide at −75° and subsequent treatment with deuterium chloride in deuterium oxide afforded 2‐monodeuteriomethyl compounds 2a, 2c and 2d, while 2‐methylfuro[3,2‐b]pyridine 1b gave a mixture of 1b, 2b, 2‐methyl‐3‐deuteriofuro[3,2‐b]pyridine 2′b and 2‐(1‐proynyl)pyridin‐3‐ol 5. The same reaction of 1a at −40° gave 3‐(1,2‐propadienyl)pyridin‐2‐ol 3 and 3‐(2‐propynyl)pyridin‐2‐ol 4. Reaction of the lithio intermediates from 1a, 1c and 1d with benzaldehyde, propionaldehyde and acetone afforded the corresponding alcohol derivatives 6a, 6c, 6d, 7a, 7c, 7d, 8a, 8c and 8d in excellent yield; while the reaction of lithio intermediate from 1b gave the expected alcohols 6b and 8b in lower yields accompanied by formation of 3‐alkylated compounds 9, 11, 12 and compound 5. While reaction of the intermediates from 1a, 1b and 1d with N,N‐dimethylacetamide yielded the 2‐acetonyl compounds 13a, 13b and 13d in good yield, the same reaction of 1c did not give any acetylated product but recovery of the starting compound almost quantitatively.
A dual pathway in the solid‐state photoreaction of nitrobenzaldehydes with indole
Authors: Meng Ji‐Ben , Du Da‐Ming , Xiong Guo‐Xiang , Wang Wen‐Guang , Wang Yong‐Mei , Koshima Hideko , Matsuura Teruo
Published: March 2009

The solid‐state photoreaction of the mixed crystals between nitrobenzaldehydes and indole was found to give nitrophenyl‐(bis‐3‐indolyl)methane (3) and nitrophenyl‐(3‐indolyl)methanol (4). The structure of the ortho isomer 4c was established by X‐ray crystallographic analysis. A dual pathway from an oxetane intermediate 5 is proposed for the formation of 3 and 4.
Syntheses of 1‐substituted 1,2,4‐triazoles, imidazoles and benzimidazoles
Authors: Sharifian Abdollah , Parang Kaykavoos , Zorrieh‐Amirian Hassan , Nazarinia Mehrdad , Shafiee Abbas
Published: March 2009

Substituted 2‐phenethyl‐1,2,4‐triazoles, 1‐phenethylimidazoles 3 and 1‐phenethylbenzimidazoles 5 were synthesized from the reaction of compound 8 with tri‐n‐butyltin hydride in good yield. The reaction of substituted‐2‐phenethyl halide with 1H‐1,2,4‐triazoles, imidazoles and benzimidazoles gave a low yield. The yield was increased by the use of substituted‐2‐phenethyl p‐toluensulfonate.
Synthesis and herbicidal properties of 3‐(2‐oxo‐1‐imidazolidinyliminomethyl)indoles
Authors: Andreani Aldo , Locatelli Alessandra , Rambaldi Mirella
Published: March 2009

The reaction of 1‐substituted 2‐chloroindole‐3‐carboxaldehydes with 1‐amino‐2‐imidazolidinone gave a series of 1‐substituted 2‐chloro‐3‐(2‐oxo‐1‐imidazolidinyliminomethyl)indoles which were evaluated as potential herbicides. The level of biological activity was not sufficient to warrant further investigation.
Furopyridines. XV. Synthesis and properties of ethyl 2‐(3‐furo[2,3‐b]‐, ‐[3,2‐b]‐, ‐[2,3‐c]‐ and ‐[3,2‐c]pyridyl)acetate
Authors: Shiotani Shunsaku , Tsuno Masahiko , Tanaka Noriyasu , Tsuiki Miho , Itoh Makoto
Published: March 2009

Ethyl 2‐(3‐furopyridyl)acetates 10a‐d were synthesized from furopyridin‐3(2H)‐ones 4a‐d by the Wittig‐Horner reaction with diethyl cyanomethylphosphonate, hydrolysis and the subsequent esterification. Reaction of compounds 10a‐d with lithium diisopropylamide (IDA) gave the corresponding methylene‐lithiated intermediate, and the subsequent reaction with benzaldehyde, acetone and iodomethane afforded the methylene‐alkylated product respectively, while N,N‐dimethylacetamide did not give any reaction product. The 2‐position of 10a, b and d is alkylated by the lithiation with excess of LDA and the successive reaction with an electrophile.
The synthesis of novel polycyclic heterocyclic ring systems via photocyclization. 15. [1] Benzothieno[3′,2′:4,5]thieno[2,3‐c]quinoline, [1] benzothieno[3′,2′:4,5]thieno[2,3‐c][1,2,4]triazolo[4,3‐a]quinoline, [1] benzothieno[3′,2′:4,5]thieno[2,3‐c]tetrazolo[1,5‐a]quinoline, thieno[3′,2′:4,5]thieno[2,3‐c][1,2,4]triazolo[4,3‐a]quinoline, and thieno[3′,2′:4,5]thieno[2,3‐c]tetrazolo[1,5‐a]quinoline
Authors: Luo Jiann‐Kuan , Kudo Hirotaka , Federspiel Ronald F. , Castle Raymond N.
Published: March 2009

The synthesis of five novel polycyclic heterocyclic ring systems via photocyclization is reported. These are [1]benzothieno[3′,2′:4,5]thieno[2,3‐c]quinoline (1), [1]benzothieno[3′,2′:4,5]thieno[2,3‐c][1,2,4]triazolo[4,3‐a]quinoline (2), [1]benzothieno[3′,2′:4,5]thieno[2,3‐c]tetrazolo[1,5‐a]quinoline (3), thieno‐[3′,2′:4,5]thieno[2,3‐c][1,2,4]triazolo[4,3‐a]quinoline (4), and thieno[3′,2′:4,5]thieno[2,3‐c]tetrazolo[1,5‐a]quinoline (5). The total assignments of the 1H and 13C nmr spectra of 1, 4, 5, and 15 were determined by utilizing two‐dimensional nmr methods.
Synthesis and antibacterial activity of 7‐ethyl‐3‐methyl‐4,7‐dihydro‐4‐oxoisothiazolo[5,4‐b]pyridine‐5‐carboxylic acid
Authors: Richardson Thomas O. , Neale Nancy , Carwell Natosha
Published: March 2009

The synthesis of the quinolone, 7‐ethyl‐3‐methyl‐4,7‐dihydro‐4‐oxoisothiazolo[5,4‐b]pyridine‐5‐carboxylic acid 4 was accomplished utilizing the Gould‐Jacobs dependent route. The compound had very weak in vitro activity as compared to nalidixic acid versus E. coli, P. aeruginosa, K. pnuemoniae, S. aureus and P. mirabilis.
First syntheses of natural products with the 2,7‐dihydroxy‐2H‐1,4‐benzoxazin‐3(4H)‐one skeleton
Authors: Kluge Michael , Hartenstein Holger , Hantschmann Achim , Sicker Dieter
Published: March 2009

2,7‐Dihydroxy‐2H‐1,4‐benzoxazin‐3(4H)‐one 11 (DHBOA) and 2,4,7‐trihydroxy‐2H‐1,4‐benzoxazin‐3(4H)‐one 14 (TRIBOA) representing aglucones of naturally occurring acetal glucoside type allelo chemicals found in Gramineae have been for the first time synthesized by two pathways both involving selective reductive cyclizations of appropriate 7‐benzyloxy‐2‐nitrophenol derivatives as precursors. TRIBOA 14 and its bioactive naturally occurring 7‐methyl ether DIMBOA have been found to undergo a hitherto unknown transformation to the corresponding 2,6‐dibromo substituted lactam forms 20 and 21 in the presence of hydrogen bromide in acetic acid, which is of value in a better understanding of the possible mode of bioactivity.
Synthesis of 6‐amino‐1‐benzyl‐4‐methylhexahydro‐1H‐1,4‐diazepine
Authors: Kato Shiro , Harada Hiroshi , Morie Toshiya
Published: March 2009

Five variants (methods A—E) of a synthetic route to 6‐amino‐1‐benzyl‐4‐methylhexahydro‐1H‐1,4‐diazepine (3b) using N‐benzyl‐N'‐methylethylenediamine (8a) are described. The reaction of 8a with 1‐benzenesulfonyl‐2‐bromomethylaziridine (7), 2‐phenyl‐4‐(p‐toluenesulfonyloxymethyl)oxazoline (13), and β, β‐dibromoisobutyric acid (15) resulted in the direct cyclization to give the precursor of 3b, 6‐substituted 1,4‐diazepine derivatives 9, 14, and 16, respectively (methods A—C). These compounds were transformed into the desired 3b, The preparation of 1,4‐diazepine ring from methyl 2‐tert‐butoxycarbonyl‐aminopropenate (18) was alternatively achieved by the intramolecular amidation of the intermediate 19a (method D) or reductive cyclization of the aminoaldehyde 23a (method E). Method E was found to efficiently produce the 6‐amino‐1,4‐diazepine 3b.
The synthesis of novel polycyclic heterocyclic ring systems via photocyclization. 16. [1]benzothieno[2′,3′:4,5]thieno[2,3‐c]quinoline and [1]benzothieno[2′,3′:4,5]thieno[2,3‐c]naphtho[1,2‐f]quinoline
Authors: Luo Jiann‐Kuan , Federspiel Ronald F. , Castle Raymond N.
Published: March 2009

The synthesis of two previously unknown polycyclic heterocyclic ring systems via photocyclization is described. The unequivocal assignment of their proton and carbon spectra was achieved by utilizing two‐dimensional nmr techniques.
Synthesis of new phenylpyrrolylpyrroles
Authors: Dumoulin H. , Rault S. , Robba M.
Published: March 2009

A series of methyl or ethyl 3‐(N‐arylpyrrol‐2‐yl)‐1N‐pyrrole‐2‐carboxylates and 2,4‐dicarboxylates has been synthesized using an alkyl isocyanides addition‐cyclization to N‐arylpyrrole derivatives such as carboxaldehydes and nitropropenes.
Pyrrolothieno[1,4]diazepines: Synthesis of alkoxy derivatives
Authors: Boulouard Michel , Rault Sylvain , Alsaïdi Abdellah , Dallemagne Patrick , Robba Max
Published: March 2009

Reactivity of 2‐(2‐formyl‐1H‐pyrrol‐1‐yl)‐3‐thiophenecarbonitrile and of 2‐(2‐formyl‐1H‐pyrrol‐1‐yl)‐3‐thiophenecarboxamide was evaluated against various alkoxides. The synthetic pathways involved in these reactions which led to new 4‐ and 6‐alkoxypyrrolothieno[1,4]diazepines are described.
Synthesis of diazepinoquinoxalines and imidazolobenzopteridines
Authors: Ueda Taisei , Asahi Masumi , Nagai Shin‐Ichi , Sakakibara Jinsaku
Published: March 2009

Diazepinoquinoxalines 3, 4 and imidazolobenzopteridines 5, 6a‐d, 7a‐d, 8, 9 were synthesized from 3‐allylamino‐6,7‐dimethyl‐2‐quinoxalinecarboxamide (1) and 2‐allylamino‐6,7‐dimethyl‐3,4‐dihydrobenzo[g]pteridin‐4‐one (2) by the intramolecular cyclization using phenylselenenyl chloride.
1,3‐Dipolar cycloaddition reactions of 1‐methyl‐ and 1,3‐dimethylindol‐2‐yl nitrile oxides
Authors: Malamidou‐Xenikaki E. , Stampelos X. N. , Coutouli‐Argyropoulou E.
Published: March 2009

Reactions of the in situ prepared 1‐methylindol‐2‐yl nitrile oxide (2a) with dipolarophiles lead to isoxazolines 5 and isoxazoles 8 and to their chloro‐derivatives 6 and 9 in good yields. Analogous reactions of the 1,3‐dimethylindol‐2‐yl nitrile oxide (2b) give the isoxazolines 10 and the isoxazoles 12 as main products as well as their oxidation products 11 and 13 in low yields. The mechanism of the reactions and the spectral elucidation of the cycloadducts are discussed.
New electrophilic reactions of 2,2′‐bisindolyls with acid chlorides and carbodienophiles
Authors: Pindur U. , Kim Y.‐S.
Published: March 2009

Some new acylation and cyclization reactions of 2,2′‐bisindolyls 1, 2 are described. The product patterns constitute acyl derivatives 3, 4, 5 and an aldehyde 7, indolo[2,3‐a]carbazoles 6, 14, 17, 19, 20 and cyclopentadiindoles 22 and 24. In the reaction with aryne or diazotated anthranilic acid, a 3‐benzoylindole derivative 9 and phenylindolyl azo dye 10 are formed. N‐methylmaleimide reacts with 2,2′‐bisindolyl 2 via Michael type addition, dehydrogenation and cyclization to several functionalized or anellated indole derivatives 11, 12, 13 and 14, respectively.
The synthesis of 5‐substituted 3‐benzoylamino‐6‐(2‐substituted amino‐1‐ethenyl)‐2H‐pyran‐2‐ones and their transformations into 2H‐pyrano[3,2‐c]pyridine derivatives
Authors: Strah Sonja , Svete Jurij , Stanovnik Branko
Published: March 2009

A new approach to the 2H‐pyrano[3,2‐c]pyridine system is described. 5,6‐Disubstituted 3‐benzoylamino‐2H‐pyran‐2‐ones 3a,b, prepared from the corresponding 1,3‐dicarbonyl compounds 1a,b and methyl (Z)‐2‐benzoylamino‐3‐dimethylaminopropenoate (2), were converted into 3‐benzoylamino‐6‐(2‐dimethylamino‐1‐ethenyl)‐5‐ethoxycarbonyl‐2H‐pyran‐2‐one (4a) and 5‐acetyl derivative 4b. The exchange of the dimethylamino group in 4a,b with aromatic amines 5a‐f,m, héteroaromatic amines 5g‐i, and benzylamines 5j‐l produced 5‐ethoxycarbonyl‐3‐benzoylamino‐6‐(2‐arylamino‐ or heteroarylamino‐or benzylamino‐1‐ethenyl)‐2H‐pyran‐2‐ones 6a‐l, and its 5‐acetyl analog 6m. The compounds 6 were cyclized in basic media into 2H‐pyrano[3,2‐c]pyridine derivatives 7a‐h. Analogously react also α‐amino acid derivatives 8a‐c and 11 as nitrogen nucleophiles producing 9a‐c, 10 and 12.
The synthesis of novel polycyclic heterocyclic ring systems. 2. Naphmo[2,1‐b:4,3‐g]bisbenzo[b]thiophene
Authors: Sasaki Kenji , Tokuda Osamu , Hirota Takashi , Luo Jiann‐Kuan , Castle Raymond N.
Published: March 2009

The novel polycyclic heterocyclic ring system, naphtho[2,1‐b:4,3‐g]bisbenzo[b]thiophene was synthesized from 5‐[2‐(2‐bromo‐3‐thienyl)ethenyl]naphtho[2,1‐b][1]benzothiophene. The assignment of its 1H and 13C nmr spectra was also accomplished by utilizing two‐dimensional nmr methods.
Studies on pyrazines. 31 Alkylation of chloropyrazine N‐oxides by nickel‐catalyzed cross‐coupling reaction with dialkylzincs
Authors: Sato Nobuhiro , Matsuura Tomoyuki
Published: March 2009

3‐Chloro‐2,5‐dimethylpyrazine 1‐oxide underwent cross‐coupling with dialkylzinc reagents forming 3‐alkyl‐2,5‐dimethylpyrazine 1‐oxides. The reaction was realized by catalytic 1,3‐bis(diphenylphosphino)‐propane nickel(II) chloride and the optimum results were examined.
Novel heterocyclic ligands with tuned hydrophobicity
Authors: Viscardi Guido , Savarino Piero , Quagliotto Pierluigi , Barni Ermanno , Botta Mauro
Published: March 2009

Heterocyclic azodyes of the pyridylazonaphthol and pyridylazoresorcinol series containing tuned hydrophobic chains have been prepared. Due to their chelating properties, the dyes are suitable candidates for preconcentration and selective separation of transition metal ions. After a discussion on the choice of the best synthetic pathway, physical and spectral uv/visible properties are presented and correlated with the structural features. A detailed analysis of nmr spectra allowed the clarification of currently unresolved signal assignments.
N,N′‐Cyclization of carbodiimides with 2‐(bromomethyl)acrylic acid. A direct entry to the system 5‐methylene‐6H‐pyrimidine‐2,4‐dione, a new class of thymine analogues
Authors: Anglada J. M. , Campos T. , Camps F. , Moretó J. M. , Pagès L.L.
Published: March 2009

Carbodiimides react under very mild conditions with 2‐(bromomethyl)acrylic acid at both N atoms to give 1,3‐disubstituted‐5‐methylene‐6H‐pyrimidine 2,4‐dione derivatives in moderate to good yields. These products behaved as good Michael acceptors towards a variety of nucleophiles such as bromine, hydrochloric acid, hydrides, etc. A plausible mechanism is proposed based on theoretical approaches and experimental results.
A new synthesis of pyrrole derivatives from tris(isopropylthio)cyclopropenylium perchlorate and thioureas
Authors: Kojima Hideo , Yamamoto Kazuhiko , Nakamura Keiichi , Inoue Hiroo
Published: March 2009

The reaction of tris(isopropylthio)cyclopropenylium perchlorate (1) with sodium thioureides 3a‐c, prepared from thioureas 2a‐c and sodium hydride, in dry acetonitrile gave the pyrrole derivatives 4a‐c, respectively, in high yields.
Syntheses of arylsulfonyl‐1,3,4‐thiadiazoles
Authors: Shafiee A. , Foroumadi A.
Published: March 2009

Reaction of sodium arylsulfinate with 2‐aryl‐5‐chloro‐1,3,4‐thiadiazole gave 2‐aryl‐5‐arylsulfonyl‐1,3,4‐thiadiazole (3) in good yield. Starting from readily available 2‐amino‐5‐benzylmercapto‐1,3,4‐thiadiazole compound 7 was obtained in three steps in moderate yield. Reaction of compound 7 with sodium arylsulfinate afforded 2,5‐diarylsulfonyl‐1,3,4‐thiadiazole (11). Oxidation of compound 10 with hydrogen peroxide in acetic acid gave 2‐arylsulfonyl‐5‐benzylsulfonyI‐1,3,4‐thiadiazole (12), in high yield.
The beckmann rearrangement of cyclohex‐2‐enone oximes. Synthesis of 4,5‐diphenyl‐2,3,4,5‐tetrahydro‐1H‐azepin‐2‐one
Authors: Lyga John W.
Published: March 2009

The Beckmann rearrangement of either syn or anti 3,4‐diphenyl‐cyclohexenone oxime 2a,b in polyphosphoric acid produces only one of the two possible isomeric unsaturated caprolactams 1. Under neutral conditions, only the syn oxime tosylate 9b rearranges to lactam 1, the anti oxime tosylate 9a remains unchanged. These results support earlier reports that alkyl migration is preferred over vinyl migration in the Beckmann rearrangement of unsaturated cyclic ketoximes. Structure proof of the lactam was made using deuterium exchange and HMQC nmr experiments.
Polycyclic N‐heterocyclic compounds. 51. Synthesis of novel 12‐substituted 11,13,15‐triazasteroidal compounds and their inhibitory activity on platelet aggregation
Authors: Sasaki Kenji , Arichi Takeshi , Ohtomo Hiromi , Nakayama Taiji , Hirota Takashi
Published: March 2009

Synthesis of 11‐substituted 1,2,4,5‐tetrahydrobenzo[h]imidazo[1,2‐c]quinazolines corresponding to 12‐substituted 11,13,15‐triazasteroid is described. Evaluation on inhibitory activity against collagen‐induced platelet aggregation of these compounds and their precursors was also investigated.
A convenient route to new phenyltetrahydroindolizines
Authors: Dallemagne Patrick , Sonnet Pascal , Enguehard Cécile , Rault Sylvain
Published: March 2009

Synthesis of new 6‐(4‐chlorophenyl)‐5,6,7,8‐tetrahydroindolizines was achieved starting from 4‐amino‐3‐(4‐chlorophenyl)butyric acid (Baclofen). The chemical pathway, involving a Clauson‐Kaas reaction and a subsequent cyclization, led to an iminium salt whose reactivity was studied.
Pyridazines LXXVIII On the reactivity of 4‐methoxy‐[(4‐pyridazinyl)methylidene]aniline in ester enolate‐imine condensation reactions
Authors: Heinisch Gottfried , Langer Thierry , Tonnel Jacques
Published: March 2009

Reactions of the pyridazine derived aldimine 1 with lithium enolates of various α‐substituted acetates were investigated. An unprecedented formation of the pyrido[3,4‐d]pyridazine system due to nucleophilic attack of a carbanion species at the β‐position of the pyridazine ring was observed.