bluuebunny/crossref_metadata_2025_split huggingface dataset:
Site selectivity in the reaction of 2‐formyl‐2H‐azirine‐N‐arylimines with diphenylketene
Authors: Nunes José , Kascheres Albert 
Published: April 2009

Abstract2‐Formyl‐2H‐azirine‐N‐arylimines 1a‐c react with diphenylketene 2 to afford 2H‐2‐azirinyl‐2‐azetidi‐nones 3a‐c and N‐aryldiphenylacetamides 4a‐c by reaction at the exo‐imine group. Derivatives containing the bulkier methyl group at the 2‐position, 1d‐f, produce only 4a‐c.
6‐Substituted thioquinanthrenes. Reaction of thioquinanthrene with radicals formed from DMF
Authors: Maślankiewicz Andrzej , Michalik Ewa 
Published: April 2009

AbstractReaction of bis‐hydrogen sulfate of thioquinanthrene with DMF‐ferrous sulfate‐hydroxylamine‐O‐sulfonic acid system took place at the α‐quinolinyl position and led to 6‐monosubstituted thioquinanthrene derivatives 1 (42%) and 2 (11%).
A new synthetic route to 2‐substituted naphtho[2,3‐b]furan‐4,9‐dione2‐Substituted Naphtho[2,3‐b]furan‐4,9‐dione
Authors: Koyanagi Jyunichi , Yamamoto Katsumi , Nakayama Kouji , Tanaka Akira 
Published: April 2009

Abstract4,9‐Dimethoxynaphtho[2,3‐b]furan 9 was obtained in 91% yield via the reductive methylation of naphtho[2,3‐b]furan‐4,9‐dione 2. After treatment of 9 with butyllithium, the mixture was allowed to react with N,N‐dimethylacetamide, followed by oxidization with cerium(IV) diammonium nitrate to give 2‐acetylnaphtho[2,3‐b]furan‐4,9‐dione 1. 2‐Formylnaphtho[2,3‐b]furan‐4,9‐dione 13 and 2‐trimethylsilyl‐naphtho[2,3‐b]furan‐4,9‐dione 14 were also obtained from 9 by a similar method. The halodesilylations of 14 easily gave 2‐iodonaphtho[2,3‐b]furan‐4,9‐dione 16, 2‐bromonaphtho[2,3‐b]furan‐4,9‐dione 17, and 2‐chloronaphtho[2,3‐b]furan‐4,9‐dione 18 in 82%, and 93% and 83% yield, respectively. Furthermore, the nitrodesilylation of 14 gave 2‐nitronaphtho[2,3‐b]furan‐4,9‐dione 3 in 77% yield.
Reaction of 4‐hydroxy‐5‐oximino‐3‐thiophenecarboxylates with hydrazines. Formation of pyrazolylthiohydroxamic acids
Authors: Robey R. L. , Alt C. A. , Van Meter E. E. 
Published: April 2009

AbstractThe reactions of 4‐hydroxy‐5‐oximino‐3‐thiophenecarboxylates with hydrazine and substituted hydrazines have been investigated. The products of the reactions have been shown to be pyrazole‐3‐ or 5‐thiohydroxamic acids rather than the hydrazones previously described by Benary and Silberstrom. Two alternate mechanisms are proposed which account for the regiochemical outcome. The structures of the pyrazole‐3‐ and 5‐thiohydroxamic acids and corresponding nitriles have been proven by independent synthesis, comparison to known compounds, and by proton and carbon magnetic resonance and long range HETCOR experiments.
Reaction of 5‐substituted‐2‐amino‐2‐oxazolines with ethoxycarbonyl isocyanate. A route to 2,3,6,7‐tetrahydro‐4H‐oxazolo[3,2‐a]‐1,3,5‐triazine‐2,4‐diones
Authors: Adetchessi Ouro , Desor Daniel , Forfar Isabelle , Jarry Christian , Leger Jean Michel , Laguerre Michel , Carpy Alain 
Published: April 2009

AbstractThe reaction of 2‐amino‐2‐oxazolines with ethoxycarbonyl isocyanate was investigated in order to access to fused 1,3,5‐triazine‐2,4‐diones with a potential 5‐HT2 antagonist activity. The reaction leads to 2,3,6,7‐tetrahydro‐4H‐oxazolo[3,2‐a]‐1,3,5‐triazine‐2,4‐diones and to 1‐carbethoxy‐3‐(2‐iminooxazolidine)ureas. During the carbamoylation the regioselectivity seems to be related to the strong nucleophilic character of the endo nitrogen atom of 2‐amino‐2‐oxazolines. The structures of two compounds were studied by X‐ray crystallography. N‐Substituted compounds have been prepared by alkylation of the 2,3,6,7‐tetrahydro‐7‐phenoxymethyl‐4H‐oxazolo[3,2‐a]‐1,3,5‐triazine‐2,4‐dione.
Mass spectrometry of 3‐oxothiazolo[3,2‐a] and [3,2‐c]pyrimidin‐5‐ones. Correlation of the intensities of the M+. and the selected fragment ions
Authors: Wybieralska Jadwiga 
Published: April 2009

AbstractThe mass spectral fragmentation of eight new 3‐oxothiazolo[3,2‐a] and [3,2‐c]pyrimidin‐5‐ones were investigated. Fragmentation pathways are proposed on the basis of accurate mass and metastable transition measurements. The correlation between the intensities of M+. and the selected fragment ions of these compounds is discussed. The data obtained created the basis for distinguishing isomers and metamers.
Pyrrolo[2,1‐c][1,4]benzodiazepines. Synthesis of new cyclic amidines and fused[a]triazolo, tetrazolo and oxadiazolo derivatives
Authors: Gillard Alain‐Claude , Foloppe Marie‐Paule , Rault Sylvain 
Published: April 2009

AbstractWe report the practical synthesis of new cyclic amidines from thiolactams and the preparation of fused[a]triazolo, tetrazolo and oxadiazolo derivatives via hydrazidines and oximes, in the pyrrolo[2,1‐c]‐[1,4]benzodiazepine series.
Unexpected formation of benzaldehydes by the reactions of dithioacetals derived from cinnamaldehydes with 2,3‐dichloro‐5,6‐dicyano‐p‐benzoquinone in aqueous solvents
Authors: Tanemura Kiyoshi , Nishida Yoko , Suzuki Tsuneo , Satsumabayashi Koko , Horaguchi Takaaki 
Published: April 2009

Abstract1,3‐Dithianes 1, 1,3‐dithiolanes 2, and diphenyl dithioacetals 3 derived from cinnamaldehydes reacted with 2,3‐dichloro‐5,6‐dicyano‐p‐benzoquinone in aqueous solvents to give benzaldehydes 4. Hydride transfer from 1–3 to 2,3‐dichloro‐5,6‐dicyano‐p‐benzoquinone followed by hydrolysis and oxidative carbon‐carbon bond cleavage would produce benzaldehydes 4.
The nucleophilic ring‐opening of N‐benzylquinuclidinium bromide
Authors: Axelsson Oskar , Peters Dan 
Published: April 2009

AbstractN‐Benzylquinuclidinium bromide was ring opened by a series of heteronucleophiles, in the presence of cesium carbonate, to yield the corresponding N‐benzyl‐4‐(2‐hetero‐ethyl)piperidines. The best yields were found with thiophenol (56%), phenol (55%), and benzimidazole (38%) as nucleophiles.
Synthesis of 11‐aminodibenzo[b,f][1,4]thiazepines and fluoro derivatives
Authors: Mettey Yvette , Lehuede Jacques , Vierfond Jean‐Michel 
Published: April 2009

AbstractThe reaction of balogenobenzonitriles with 2‐aminobenzenethiol is a new route, in a “one‐pot” or two‐step approach, to 11‐aminodibenzo[b,f][1,4]thiazepine and fluoro derivatives.
Synthesis of 1,2,4‐triazole and thiazole analogs of ketoconazole
Authors: Huang Liang‐Fu , Kim Jang‐Woo , Bauer Ludwig , Doss George 
Published: April 2009

AbstractThe synthesis of 1,2,4‐triazole and thiazole analogs of ketoconazole is described in which one of the α azole ring carbons is linked to C‐2 of the ketal by means of a three methylene tether. Lithiation of 1‐methyl‐1,2,4‐triazole and thiazole and subsequent alkylation with 2‐(2,4‐dichlorophenyl)‐2‐(3‐iodopropyl)‐1,3‐dioxolane produced, after an aqueous acidic workup, 2,4‐dichlorophenyl 3‐[5‐(1‐methyl‐1,2,4‐triazolyl) and 2‐thiazolyl]propyl ketones, respectively. Ketalization with glycerol furnished the corresponding diastereomeric pairs of cis and trans 1,3‐ dioxolanes. The reaction of 2,4‐dichlorophenyl 3‐[5‐(1‐methyl‐1,2,4‐triazolyl)]propyl ketone with 3‐mercapto‐1,2‐propanediol produced the corresponding diastereomeric cis and trans hydroxymethyl 1,3‐oxathiolanes. The diastereomeric racemates were separated by column chromatography and their stereochemistry established by nOe nmr experiments. Some of these racemic cis ketal alcohols were converted by benzyl bromide to the corresponding benzyl ethers. Several of these racemic cis‐ketals were reacted, first with methanesulfonyl chloride, then with 1‐acetyl‐4‐(4‐hydroxyphenyl)piperazine, to furnish the title compounds.
Convenient synthesis of 6‐substituted‐2‐chloro‐5,12‐dihydro‐5‐oxobenzoxazolo[3,2‐a]quinolines and N‐acylated‐3‐chlorodibenz[b,e][1,4]oxazepin‐11(5H)‐ones
Authors: Chung Sang J. , Joo Keum Chan , Kim Dong H. 
Published: April 2009

AbstractConvenient synthesis of variously substituted 2‐chloro‐5,12‐dihydro‐5‐oxobenzoxazolo[3,2‐a]quinolines at the 6‐position and N‐acylated‐3‐chlorodibenz[b,e][1,4]oxazepin‐11(5H)‐ones are reported. The former compounds were obtained in 65–93% yield by simply heating N‐acyl‐4‐chloro‐N‐(2‐hydroxyphenyl)‐anthranilic acids in acetic anhydride for 4 hours, and the latter by heating sodium salt of N‐acyl‐4‐chloro‐N‐(2‐hydroxyphenyl)anthranilic acids with acetic anhydride.
Furopyridines. XXI. Synthesis of cyano derivatives of furo‐[2,3‐b]‐, ‐[2,3‐c]‐ and ‐[3,2‐c]pyridine and their conversion to derivatives having another carbon‐substituent
Authors: Shiotani Shunsaku , Taniguchi Katsunori 
Published: April 2009

AbstractCyanation of furo[2,3‐b]‐, ‐[2,3‐c]‐ and ‐[3,2‐c]pyridine N‐oxides 1a, 1b and 1c by the Reissert‐Henze method, reaction with benzoyl chloride and trimethylsilyl cyanide in dichloromethane and the reaction with trimethylsilyl cyanide and triethylamine in acetonitrile afforded 6‐cyanofuro[2,3‐b]‐ 2a, 7‐cyanofuro[2,3‐c]‐ 2b and 4‐cyanofuro[3,2‐c]pyridine 2c in moderate to excellent yield. The cyano group in 2a, 2b and 2c was converted to carboxamides 3a, 3b and 3c, ethyl imidates 5a, 5b and 5c and ethyl carboxylates 6a, 6b and 6c. Reaction of the N‐oxides with trimethylsily bromide in acetonitrile gave the deoxygenated furopyridine 7a and 7d, bifuropyridyl 8b and 8c, and the N‐oxide 9 of 8c.
Retro‐ene reactions in heterocyclic synthesis, III. A new route to 4,5‐dihydrooxazoles and 5,6‐dihydro‐4H‐1,3‐oxazines
Authors: Ito Kunio , Miyajima Shingo 
Published: April 2009

AbstractMethyl (E)‐4,4‐dimethyl‐5‐oxo‐2‐pentenoate (1, X = O) reacted with 1,2‐ or 1,3‐aminoalcohols 3 to yield oxazolidines 4a‐c or tetrahydro‐1,3‐oxazines 4d,e. The corresponding imino ester 1 (X = NBu‐t) also gave 4 on reaction with 3. Compounds 4 on heating at 230° yielded 4,5‐dihydrooxazoles 5a‐c or 5,6‐dihydro‐4H‐1,3‐oxazines 5d,e along with methyl 4‐methyl‐3‐pentenoate (6).
Haloacetylated enol ethers. 8 [12]. Reaction of β‐alkoxyvinyl trihalomethyl ketones with guanidine hydrochloride. Synthesis of 4‐trihalomethyl‐2‐aminopyrimidines
Authors: Zanatta Nilo , Cortelini Maria de F. M. , Carpes Marcos J. S. , Bonacorso Helio G. , Martins Marcos A. P. 
Published: April 2009

AbstractIn this work the results of the reaction of β‐alkoxyvinyl trihalomethyl ketones 1, 2a‐e, with guanidine hydrochloride are reported. Depending on the ketone 1 or 2 and the conditions under which the reactions were carried out, 4‐trihalomethyl‐2‐amino pyrimidines, β‐alkoxyvinyl carboxylic acids, or β‐acetal carboxylic esters were obtained.
Facile and convenient synthesis of 2,6‐disubstituted 4H‐1,3‐oxazin‐4‐one derivatives
Authors: Morita Yasuo , Kaneko Masakazu , Matsuzawa Sumiko , Yamamoto Yutaka 
Published: April 2009

AbstractFacile and convenient methods for the preparation of a variety of 2,6‐disubstituted 4H‐1,3‐oxazin‐4‐ones 3 by three complementary methods are described. Treatment of the branched aliphatic imidate 2c,d with diketene 1 in the presence of a catalytic amount of acetic acid affords 2‐substituted 6‐methyl‐1,3‐oxazin‐4‐ones 3c,d, whereas the unbranched imidate 2b,e gave oxazines 3b,e and pyrimidines 4b,e (Method A). The reaction of acyl Meldrum's acid 5 with imidate 2 afford 2,6‐disubstituted oxazine 3, though the alkylimidate with acetyl Meldrum's acid yielded 3 and 5‐acetyl‐1,3‐oxazine‐4,6‐dione 8 (Method B). The cylodehydration of acylacetylcarboxamide 13 with acid, such as 70% perchloric acid or fluorosulfonic acid, afforded 1,3‐oxazines 3 (Method C).
Synthesis of pyrido[2,3‐d]pyrimidinones by the reaction of aminopyrimidin‐4‐ones with benzylidene meldrum's acid derivatives
Authors: Quiroga Jairo , Hormaza Angelina , Insuasty Braulio , Nogueras Manuel , Sánchez Adolfo , Hanold Norbert , Meier Herbert 
Published: April 2009

AbstractA series of pyrido[2,3‐d]pyrimidine‐4,7‐diones 5a‐h were prepared from 6‐amino‐4‐pyrimidones 1 and benzylidene Meldrum's acid derivatives 2 by cyclization reactions in boiling nitrobenzene. The structure of 5, determined by nmr measurements, reveals a selective orientation of 1 and 2 in the addition step.
Synthesis of halosulfuron‐methyl via selective chlorination at 3‐ and/or 5‐position of pyrazole‐4‐carboxylates
Authors: Morimoto Katsushi , Sato Toshiaki , Yamamoto Susumu , Takeuchi Hiroshi 
Published: April 2009

AbstractReactions of methyl pyrazole‐4‐carboxylates 4b‐d with N‐chlorosuccinimide under heating conditions without a solvent gave methyl 3,5‐dichloro‐1‐methylpyrazole‐4‐carboxylate 4a in good yields. The reaction of 4a with sodium hydrosulfide led to a nucleophilic substitution on the 5‐position regioselectively to afford methyl 3‐chloro‐1‐methyl‐5‐mercaptopyrazole‐4‐carboxylate 6a, which was followed by oxidative chlorination and amination to obtain 3‐chloro‐1‐methyl‐5‐sulfamoylpyrazole‐4‐carboxylate 2a. Finally, the reaction of 2a with phenyl 4,6‐dimethoxypyrimidin‐2‐yl carbamate 7 provided methyl 3‐chloro‐5‐(4,6‐dimethoxypyrimidin‐2‐ylcarbamoylsulfamoyl)‐1‐methylpyrazole‐4‐carboxylate (halosulfuron‐methyl) 1a promising herbicide in com.
Synthesis and metalation of trifluoromethylpyrimidines. Metalation of diazines. XVI
Authors: Plé N. , Turck A. , Heynderickx A. , Quéguiner G. 
Published: April 2009

AbstractA new route to trifluoromethylpyrimidines is described. Lithiation of trifluoromethylpyrimidines was successfully achieved and was used to synthesize new pyrimidine derivatives. A new synthetic route to a biologically active molecule with antimycotic activities is reported.
A novel synthesis of 3‐halo‐2‐phenylquinoline‐4‐carboxylic acids
Authors: Raveglia Luca F. , Giardina Giuseppe A. M. , Grugni Mario , Rigolio Roberto , Farina Carlo 
Published: April 2009

AbstractThe 3‐chloro and 3‐bromo‐2‐phenylquinoline‐4‐carboxylic acids were obtained in good yields through a novel procedure, entailing the synthesis of the 3‐amino intermediate and the subsequent replacement of the amino group with chlorine or bromine, according to the Sandmeyer reaction.
Friedel‐crafts reactions of 2‐amino‐4‐(alkyl or aryl)oxazoles with acid chlorides and acid anhydrides: Synthesis of 5‐acyl‐2‐amino‐4‐alkyloxazoles
Authors: Mekonnen Belew , Crank George 
Published: April 2009

AbstractAcid chlorides and anhydrides react with 2‐amino‐4‐alkyloxazoles in the presence of aluminum chloride to produce 5‐acyl substituted 2‐amino‐4‐alkyloxazoles in modest yields. However, in the absence of the Lewis acid reaction occurs at the amino group to give the corresponding amides. This provides a viable entry for functionalising and making carbon‐carbon bond at C‐5 of this heterocyclic system.
A new and facile synthesis of imidazo[2,1‐b]oxazoles
Authors: Mekonnen Belew , Crank George , Craig Donald 
Published: April 2009

AbstractAn efficient and clean two step procedure for the synthesis of imidazo[2,1‐b]oxazoles has been developed from 2‐aminooxazoles using titanium(IV) chloride assisted cyclization, and a variety of imidazo[2,1‐b]oxazoles have been synthesized in good yields. The structure of one of the products was confirmed by X‐ray crystallographic analysis.
Multiple 1,2,3‐thiadiazoles
Authors: Al‐Smadi Mousa , Hanold Norbert , Meier Herbert 
Published: April 2009

AbstractA series of compounds 3a‐d,i‐n with two or three 1,2,3‐thiadiazole rings, useful for photocrosslinking processes, was prepared from the di‐ or triketones 1a‐d,i‐n via the corresponding hydrazones 2a‐d,i‐n by applying the Hurd‐Mori method. A special synthetic sequence, 1e, 2e, 3e, 3f/3g, was elaborated for the olefinic system 3h.
Stereoselective synthesis of cyclic ether compounds via reductive cleavage of bicyclic ketals
Authors: Jun Jong‐Gab 
Published: April 2009

AbstractBicyclic ketals in the 6,8‐dioxabicyclo[3.2.1]octane system readily reacted with triethylsilane‐boron tri‐fluoride etherate at room temperature to give only the cis‐tetrahydropyranol derivatives via C5‐O6 bond cleavage. Three‐ and erythro‐alcohols were prepared selectively from the endo‐ and exo‐ketal, respectively. Dehydrated products also formed when the tertiary alcohol was involved under these reaction conditions. However, the cleavage reaction with aluminum hydride gave the trans‐tetrahydropyranol as the major product without dehydration.
On triazoles XXXVII.. The correct structure of the products formed from 1,2,4‐triazolethiones with α‐halogenated acetophenones
Authors: Reiter József , Kajtár‐Peredy Mária , Bauer Ludwig 
Published: April 2009

AbstractThe reaction of 1,2,4‐triazolethiones with α‐halogenated acetophenones was re‐investigated. It was proven that in contrast to the literature data the products obtained were S‐alklylated derivatives.
Diastereoselective michael addition of nitrogen and sulfur‐nucleophiles to α,β‐unsaturated δ‐thiolactams
Authors: Sośnicki Jacek G. , Jagodziński Tadeusz S. , Liebscher Jürgen 
Published: April 2009

Abstract5,6‐Dihydropyridine‐2‐thiones 2 are synthesized from 5,6‐dihydropyridin‐2‐ones 1 and Lawesson reagent. Stereoselective Michael‐like addition of amines, methylhydrazine or functionalized thiols affords trans piperidine‐2‐thiones 5 with the corresponding heterosubstituent in position 4 as major products. The configuration of the adducts 5 was determined by nmr‐techniques.
Syntheses and spectral properties of 2,3,7,8‐tetracyano‐5,10‐dihydrodipyrazino[2,3‐b:2′,3′‐e]pyrazine
Authors: Jaung Jae‐Yun , Fukunishi Koushi , Matsuoka Masaru 
Published: April 2009

AbstractBase catalized intermolecular cyclization of 2‐amino‐3‐chloro‐5,6‐dicyanopyrazines gave 5,10‐disubsti‐tuted‐2,3,7,8‐tetracyano‐5,10‐dihydrodipyrazino[2,3‐b:2′,3′‐c]pyrazines 11–20. These compounds have rather small molecular size but have strong intramolecular charge‐transfer chromophoric system. They have strong fluorescence in solution and some have fluorescence even in the solid state which are very important to evaluate their electroluminescence property as an emitter for electroluminescence devices. The physical, structural, and electronic properties of these new 2,3,7,8‐tetracyano‐5,10‐dihy‐drodipyrazino[2,3‐b:2′3′‐e]pyrazines were studied using uv‐visible spectroscopy and the Pariser‐Parr‐Pople molecular orbital calculation method.
Semi‐synthesis of paclitaxel from naturally occurring glycosidic precursors
Authors: Rao Koppaka V. 
Published: April 2009

AbstractPaclitaxel, an antitumor drug effective on ovarian and breast carcinomas, is currently being produced both by direct isolation from the bark of Taxus brevifolia and by semi‐synthesis from a natural precursor, 10‐deacetyl baccatin III. Although other potential precursors such as 10‐deacetyl paclitaxel‐7‐xyloside were known since 1984, their conversion to paclitaxel could not be achieved because of the lack of suitable methodology for hydrolyzing the xylose residue, compatible with the stability of the compound. A method is described here using periodate, followed by phenylhydrazine, to effect deglycosidation of 10‐deacetyl paclitaxel‐7‐xyloside to form 10‐deacetyl paclitaxel. In addition, by including an intermediate acetylation step before the reaction with phenylhydrazine, “direct” conversion of this xyloside to paclitaxel itself, is described. Because 10‐deacetyl paclitaxel‐7‐xyloside occurs at >0.1% in the bark of Taxus brevifolia, its successful hydrolytic conversion to paclitaxel represents an extremely important reaction for the enhanced availability of this drug.
A convenient synthesis of 1,3‐oxazolidin‐4‐ones and 1,3‐oxazin‐4‐ones
Authors: Wanner Klaus Th. , Weber Ulrich 
Published: April 2009

Abstract1,3‐Oxazolidin‐4‐ones and 1,3‐oxazin‐4‐ones were synthesized by formal cyclocondensation of imines with α‐ or β‐hydroxy acids.
Hydrogen‐deuterium exchange in dimethylpyridines
Authors: Kebede Naod , Pavlik James W. 
Published: April 2009

AbstractDimethylpyridines undergo deuterium‐hydrogen exchange when heated in deuterium oxide containing potassium carbonate at ring positions 2 and 6 when these positions are unsubstituted and at methyl groups located at ring positions 2,4, and 6 exclusively.
Preparation of thiapyrimidinophanes from 2,4‐dithiouracil
Authors: Itahara Tosbio 
Published: April 2009

AbstractTreatment of 2,4‐dithiouracil with dihaloalkanes under a basic condition gave three types of thiapyrim‐idinophanes, whose structures were confirmed by their nmr and mass spectral data.
A facile synthesis of the lowest homologues of meso‐tetraalkylporphyrin
Authors: Neya Saburo , Funasaki Noriaki 
Published: April 2009

AbstractUtilization of a less stoichiometric amount of aldehyde in portions and addition of water to the reaction mixture depressed the tar formation, affording much easier isolation of meso‐tetraalkylporphyrins. The title porphyrins bearing methyl, ethyl, or n‐propyl substituents were synthesized in isolated yields of 10,10, and 8%, respectively.
Long‐range 1H‐15N two‐dimensional heteronuclear shift correlation of the alkaloid vincamine at natural abundance
Authors: Martin Gary E. 
Published: April 2009

AbstractLong‐range 1H‐15N heteronuclear correlation pathways in the alkaloid vincamine, a structural constituent or biogenetic congener of numerous Vinca alkaloids, are reported. Correlations were observed through the use of the GHNMQC (Gradient‐enhanced Hydrogen‐Nitrogen Multiple Quantum Coherence) 2D nmr experiment at natural abundance. An unanticipated four‐bond coupling between the H15a resonance and N4 was observed in contrast to the typical two‐ and three‐bond coupling pathways. Nitrogen‐15 chemical shift comparisons are drawn between vincamine and structurally related alkaloids including ajmaline and the velbanamine portion of the semi‐synthetic alkaloid vinorelbine (NavelbineTM).
A novel route to 1‐benzyl‐1,2,4‐triazole derivatives through disproportionation of isothiosemicarbazones
Authors: Yamazaki Chiji , Ohno Mariko 
Published: April 2009

AbstractAromatic isothiosemicarbazones 1–4 underwent disproportionation at elevated temperature in the presence of a thiol or a thiol‐releasing substance to give 1‐arylmethylene‐3‐alkylthio‐5‐aryl‐1H‐1,2,4‐triazole derivatives 6–9 in moderate yields. An isothiosemicarbazone of aliphatic aldehyde with no α‐hydrogen did not give rise to the corresponding disproportionation under the similar conditions. Cross reaction occurred between two different isothiosemicarbazones but the cross compound could be isolated only in a poor yield. Any inert solvent markedly inhibited the disproportionation reaction even only with a slight dilution. A tentative reaction mechanism, in which it might involve a potential nitrene‐sulfonium ion pair as a key step, is presented.
Synthesis of 6‐cyanopurines and the isolation and X‐ray structure of novel 2H‐pyrroles
Authors: Alves M. José , Carvalho M. Alice , Proença M. Fernanda J.R.P. , Booth Brian L. , Pritchard Robin G. 
Published: April 2009

Abstract(Z)‐N1‐(2‐Amino‐1,2‐dicyanovinyl)‐N2‐substituted‐formainidines react with dimethylformamide diethyl acetal at room temperature to give 6‐cyanopurines as the major product together with novel 5‐amino‐2‐arylimino‐3,4‐di[(N,N‐dimethylamino)methylideneamino]‐2H‐pyrroles, which have been fully characterised and a single crystal X‐ray analysis has been carried out on the N‐phenyl derivative.
Synthesis and spectral properties of methyl 5‐[(o‐, m‐, and p‐R)‐phenoxy]‐2‐benzimidazolecarbamate
Authors: Cortés Eduardo Cortés , Anaya Luis Angel Araluce 
Published: April 2009

AbstractThe preparation of eleven novel methyl 5‐[(o‐, m‐, p‐R)‐phenoxy‐2‐benzimidazolecarbamates with possible pharmacological activity as anthelmintics is described. The structure of all products was corroborated by ir, 1H‐nmr, 13C‐nmr and mass spectra.
Synthesis and aggregation of cationic porphyrins
Authors: Dancil Keiki‐Pua S. , Hilario Lynn F. , Khoury Richard G. , Mai Kim U. , Nguyen Chi K. , Weddle Katherine S. , Shachter Amy M. 
Published: April 2009

AbstractTetra(N‐R‐pyridinium‐4‐yl)porphyrin and tetra(N‐R‐pyridinium‐3‐yl)porphyrin derivatives were synthesized with R = 3, 6, and 8 carbon alkene, alcohol and carboxylic acid chains. Self‐aggregation of these systems was studied at I = 0.1 using visible spectroscopy. N‐Alkyl chain length and functionality were determined to play the dominant role in aggregation of the cationic porphyrins. Position of peripheral charge (meta vs. para) also influenced spectral changes and the nature of the aggregate.