bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel heterocycles. 10. Reactions of 1,3,2‐benzodiazaphosphorin‐4(1H)‐one 2‐oxides
Authors: Coppola Gary M. 
Published: March 2009

AbstractReactions of 1,3‐disubstituted‐2,3‐dihydro‐1,3,2‐benzodiazaphosphorin‐4 (1 H)‐one 2‐oxides (1) with various electrophiles were investigated. The treatment of 1 with aldehydes in the absence of a basic catalyst directlyafforded alcohols 7a‐h in good yield. The product from the reaction of 1 with chloral, on treatment with sodium hydride, resulted in the formation of a dichloroepoxide (8). When 1 was allowed to react with isocyanates or isothiocyanates in the presence of triethylamine, amides 10a‐e and thioamide 11 were produced in good yield. Compounds 1a and 1b were readily halogenated on their phosphorus atom by treatment with either carbon tetrachloride or carbon tetrabromide and triethylamine. The P‐chloro compound 12a reacted with ethanol to furnish the P‐ethoxy derivative 13 and, in an attempt to react 12a with bis (2‐chloroethyl) amine, anhydride 14 was formed in high yield. Spectral data for the majority of the products are also discussed.
Reaction of N‐amino‐4,6‐dimethylpyrimidinium mesitylene sulfonate with nucleophiles . A 15n‐study
Authors: van der Plas Henk C. , Baloniak Sylwester , Jongejan Hugo 
Published: March 2009

AbstractReaction of N‐amino‐4, 6‐dimethylpyrimidinium mesitylene sulfonate with liquid ammonia, with an aqueous solution of sodium hydroxide or with hydrazine leads to 3, 5‐dimethylpyrazole. Reaction of this salt with 15N‐labelled hydrazine gave incorporation of nitrogen‐15 in 3,5‐dimethylpyrazole and in recovered starting material. Evidence has been presented that the initial step in the ring contraction with hydrazine is the addition of the nucleophile to C‐2 and C‐6. It is suggested that in the presence of a base the reactive species is probably 4,6‐dimethylpyrimidinio amide.
Oxidation and photochemical reactions of 3‐phenyl‐2H‐1,4‐benzoxazines
Authors: Battistoni P. , Bruni P. , Fava G. , Tosi G. 
Published: March 2009

Abstract3‐Phenyl‐2H‐1, 4‐benzoxazines 4‐oxides are light sensitive compounds, irradiation leads to 3‐phenyl‐2H‐1,4‐benoxazines and to their 3‐oxidized derivatives, whenever possible. Intermediate oxaziridines are formed during the photolysis and transformed into stable nitroxide radicals. The structure of these radicals was confirmed through peracid oxidation of 3‐phenyl‐2H‐1,4‐benzoxazines and 3‐phenyl‐3, 4‐dihydro‐2H‐1,4‐benzoxazines. A reaction mechanism is proposed on the basis of experimental observations.
Synthesis of all of the monomethyl isomers of naphtho[2,1‐b]thiophene
Authors: Tominaga Yoshinori , Tedjamulia Marvin L. , Castle Raymond N. , Lee Milton L. 
Published: March 2009

AbstractAll isomers of the monomethylnaphtho[2,1‐b]thiophenes were synthesized by photocyclization of 2‐styryl‐thiophenes which were either prepared by the Wadsworth‐Emmons reaction or by the condensation of 2‐lithiothiophene with the corresponding carbonyl compounds.
Ring opening reactions of indeno[1,2‐c]isoxazolones
Authors: Lemke Thomas L. , Sawhney Kailash N. 
Published: March 2009

AbstractNucleophilic attack of 8‐substituted indeno[1, 2‐c]isoxazol‐7‐ones (1) and 3‐phenylindeno[1, 2‐c]isoxazol‐4‐one (4) by dimethylsulfoxide or triphenylphosphine results in cleavage of the nitrogenoxygen bond of the isoxazole ring leading to the formation of sulfoximides (2 and 5) and phosphazenes (3 and 8).
Reactions of some 5‐substituted imidazo[2,1‐b]‐1,3,4‐thiadiazoles
Authors: Hough T. L. 
Published: March 2009

AbstractThe conversion of the 5‐bromoimidazo[2, 1‐b]‐1, 3, 4‐thiadiazole Ib to the 5‐cyano derivative Ic is firstly described. The 5‐nitroimidazo[2, 1‐b]‐1, 3, 4‐thiadiazole Id is smoothly reduced by aluminium amalgam to the 5‐imino‐5, 6‐dihydroimidazo[2, 1‐b]‐1, 3, 4‐thiadiazole II. However, reaction of Id with sodium dithionite unexpectedly gives 1, 3, 4‐thiadiazoles III and V depending upon conditions.
4‐Azapteridines. I. Covalent addition products of the pyrazino[2,3‐e]‐as‐triazine ring system
Authors: Tzeng Cherng Chyi , Panzica Raymond P. 
Published: March 2009

AbstractRing closure of 5, 6‐diamino‐3‐methylthio‐as‐triazine with 40% aqueous glyoxal provided the 6, 7‐dihydrate of the pyrazino[2, 3‐e]‐as‐triazine (4‐azapteridine) ring system. The C7 hydroxy group of this dihydrate underwent exchange in methanol or ethanol affording the 7‐alkoxy, 6‐hydroxy derivatives.
The synthesis of dinaphthothiophenes
Authors: Tedjamulia Marvin L. , Tominaga Yoshinori , Castle Raymond N. , Lee Milton L. 
Published: March 2009

AbstractThe synthesis of dinaphtho[1,2‐b:2′,3′‐d]thiophene (6), dinaphtho[2,1‐b:2′,3′‐d]thiophene (15), dinaphtho‐[1,2‐b:1′,2′‐d]thiophene (20), dinaphtho[2,1‐b:1′,2′‐d]thiophene (26), dinaphtho[2,3‐b:2′,3′‐d]thiophene (37) and dinaphtho[1,2‐b:2′,1′‐d]thiophene (45) has been accomplished.
Stereochemical studies. 58. Saturated heterocycles. 39. Preparation and steric structures of dihydro‐1,3‐oxazines, 1,3‐oxazin‐2‐ones and 1,3‐oxazine‐2‐thiones fused with norbornane and norbornene
Authors: Stájer1 Géza , Szabó Enikö A. , Fülöp Ferenc , Bernáth Gábor , Sohár Pál 
Published: March 2009

Abstract3‐endo‐Aminobicyclo[2.2.1]hept‐5‐ene‐2‐endo‐carboxylic acid (1), prepared from endo‐norborn‐5‐ene‐2,3‐dicarboxylic acid anhydride, and the analogous saturated cis‐exo‐amino acid (3) were reduced with lithium aluminum hydride to the aminoalcohols 2 and 4; the latter were cyclized by means of arylimino ethers to methylene‐bridged tetrahydro‐ (6a‐c) and hexahydro‐3,1‐benzoxazines (7b‐d), respectively. The endo (2) and exo (4) aminoalcohols were converted to methylene‐bridged tetrahydro‐3,1‐benzoxazin‐2‐one (9) and hexahydro‐3,1‐benzoxazin‐2‐one (12) with ethyl chloroformate and sodium methoxide; treatment of the alcohols with carbon disulfide gave, via the dithiocarbamates, the corresponding 2‐thiones (11, 13). The structures were confirmed by ir and nmr spectroscopy.
Reactions of 1‐glucosyl‐5‐nitro‐1,2,4‐triazole with nucleophiles
Authors: Camarasa María José , De Las Heras Federico G. 
Published: March 2009

Abstract1‐Glucosyl‐5‐nitro‐1,2,4‐triazole reacted with nucleophiles, such as water, aziridine, chloride ion and 4‐dimethylaminopyridine to give the corresponding 5‐substituted 1‐glucosyl‐1,2,4‐triazole derivatives.
New synthesis of 11‐acyl‐5,11‐dihydro‐6H‐pyrido[2,3‐b][1,4]‐benzodiazepin‐6‐ones and related studies
Authors: Kovač T. , Oklobdžija M. , Comisso G. , Decorte E. , Fajdiga T. , Moimas F. , Angeli C. , Zonno F. , Toso R. , Šunjić V. 
Published: March 2009

AbstractNew synthesis of 11‐acyl‐5,11‐dihydro‐6H‐pyrido[2,3‐b][1,4]benzodiazepin‐6‐ones (42‐44) is reported. The crucial steps (Scheme VI) represented N‐oxydation of 1 (1A) to 35 (35A), facilitated ring‐closure of 36 into 37, its subsequent N‐α‐chloroacetylation to 38, aminolysis to 39‐41 (involving N‐O anchimeric assistance as depicted in 38A) and deoxygenation to 42‐44 (Scheme VII). The central intermediate 37 is also obtained on oxygenation of 2, a new synthesis of which was reported in the previous paper of this series [3]. Other attempts of cyclisation “from the top” or “from the bottom” (Scheme I) are described. Thus, interaction of 1 with acetamide afforded 3 and 4 instead of the expected 2A. Compound 5 cyclised into 3‐pyridoquinazolone 6 while its 2‐(4′‐methylpiperazin‐1′‐yl analogue 9 was observed to be unstable for the attempted ring‐opening and reclosure to 42. “From the bottom” cyclisations of 10A‐10C, via intermediary amines 11A‐11C failed and pyridoquinazolinone 13 was isolated (Scheme V). The attempted oxidative cyclisation of the compounds 15 and 18 into 2 and 42, respectively, 13 afforded imidazolo[5,4‐b]pyridine derivative (18–19), while 15 remained unchanged. 3‐Acylamino‐2‐arylaminopyridines (21‐24), cyclised into imidazolopyridines 29‐30. Model compounds 45‐50 were prepared to study selective aminolysis of the chlorine atoms in 2‐chloro‐3‐(2′‐chlorobenzoyl)aminopyridine 1, and its N‐oxide 35.
New efficient total syntheses of derivatives of protoporphyrin‐IX bearing deuteriated methyl groups
Authors: Smith Kevin M. , Pandey Ravindra K. 
Published: March 2009

AbstractNew total syntheses of hemins which are regioselectively deuteriated in the 1,5 (2), 5 (3) or 8 (4) methyl groups are described. Syntheses of hemins 2 and 3 follow the progression from pyrromethane 12 to t‐butyl tripyrrene‐carboxylate hydrobromide (17 and 30) and then to a,c‐biladiene dihydrobromide (19 and 31), but for reasons of economy in use of labeled monopyrroles, the o,c‐biladiene dihydrobromide 40 for hemin 4 is approached in an initially “clockwise” manner by synthesis of a benzyl tripyrrene‐carboxylate hydrobromide 37 from the pyrromethane 5. Cyclization of the a,c‐biladienes (19, 31, and 40) was accomplished by brief heating in dimethylformamide in the presence of copper(II) chloride.
o‐Hydroxyphenylureas. Intermediates in the urea fusion synthesis of 2‐benzoxazolinones
Authors: Nachman Ronald J. 
Published: March 2009

Abstracto‐Hydroxyphenylureas have been identified as intermediates in the urea fusion synthesis of 2‐benzoxazolinones. The pyrolysis of these intermediates represents a new alternate synthesis of the benzoxazolinone ring system.
On the assignment of the 13C‐NMR spectrum of phenothiazine
Authors: Hallberg A. , Al‐Showaier I. , Martin A. R. 
Published: March 2009

AbstractThe assignment of the 13C‐nmr spectrum of phenothiazine was made by comparison with the 13C‐nmr spectrum of 1,9‐dideuteriophenothiazine, synthesized via repeated lithiations and subsequent deuterations of phenothiazine.
Autocorrelated 13c‐13c double quantum coherence two‐dimensional nmr spectroscopy: Utilization of a modified version of the technique as an adjunct in the total assignment of the 1h‐ and 13c‐nmr spectra of the mutagen phenanthro[3,4‐b]thiophene
Authors: Musmar M. J. , Willcott M. Robert , Martin Gary E. , Gampe Robert T. , Iwao Masatomo , Lee Milton L. , Hurd Ralph E. , Johnson Leroy F. , Castle Raymond N. 
Published: March 2009

AbstractDevelopment of successively higher field nmr spectrometers has facilitated the study of increasingly more complex molecules, although smaller molecules such as phenanthro[3,4‐b]thiophene still offer very substantial assignment problems because of the highly congested nature of their 1H‐ and 13C‐nmr spectra. Assignments of such spectra, if they are to be unequivocal, frequently require the utilization of two‐dimensional nmr spectroscopic techniques. Total assignments of the 1H‐ and 13C‐nmr spectra of phenanthro[3,4‐b]thiophene are reported. Assignments were based on a conventional high resolution 500 MHz 1H‐nmr spectrum, autocorrelated two‐dimensional 1H‐nmr spectra (COSY), two‐dimensional 1H‐13C chemical shift correlation spectra and a modified version of autocorrelated 13C‐13C double quantum coherence two‐dimensional nmr spectroscopy. From NOE measurements, a separation of 1.99 Å between H1 and H11 was computed, suggesting that phenanthro[3,4‐b]thiophene has a pronounced helical conformation in solution.
2,1‐Benzisothiazoles. XII. . The use of n‐substituted‐2,1‐ benzisothiazolium salts as synthetic equivalents of o‐aminobenz‐ aldehydes. A simple synthesis of some 2‐Quinolones
Authors: Davis Michael , Hudson Michael J. 
Published: March 2009

AbstractN‐Substituted‐2,1‐benzisothiazolium salts 2 react with ethyl cyanoacetate in pyridine solution to give substituted 3‐cyano‐2‐quinolones 5.
A comparison of some friedel‐crafts and grignard reactions of optically active phenyloxirane
Authors: Taylor Stephen K. , Haberkamp William C. , Brooks Dee W. , Whittern David N. 
Published: March 2009

AbstractThe Friedel‐Crafts reactions of optically active phenyloxirane with toluene and anisole were examined for stereospecificity. The enantiomeric ratios of the diarylethanol products were determined and compared to those of the same products obtained from the reaction of p‐tolyl and p‐methoxyphenyl Grignard reagents with optically active phenyloxirane. The p‐tolyl Grignard and Friedel‐Crafts products gave similar enantiomeric ratios (approximately 64:36 and 60:40, respectively). However, in the p‐methoxyphenyl products from the Grignard and Friedel‐Crafts reactions, different enantiomers predominated (ratios of 33:67 and 62:38, respectively).
Convenient preparative methods for N‐aryl‐γ‐pyridones from γ‐pyrones
Authors: Looker James H. , Cliffton Michael D. 
Published: March 2009

Abstract2‐Hydroxymethyl‐5‐methoxy‐4‐H‐pyran‐4‐one (1) reacts with aniline and six aniline derivatives in very dilute aqueous hydrochloric acid at reflux temperature to give the N‐aryl‐γ‐pyridone. A second procedure utilizes the aromatic amine hydrochloride by reacting it with 1 in aqueous medium at reflux temperature. p‐Nitroaniline hydrochloride and 1 give the N‐aryl‐γ‐pyridone in 65% yield, as opposed to 12% from the dilute acid procedure.
Thermal fragmentations of nitrated 8‐quinolinols
Authors: Sutter Peter , Weis Claus D. 
Published: March 2009

Abstract8‐Quinolinols which are substituted in the aromatic nucleus by nitro‐, chloro‐, or by sulfonic acid groups underwent a neat thermal fragmentation upon heating in 75% nitric acid as reaction medium yielding 2,3‐dicarboxypyridinium nitrate. The scope and the mechanism of these reactions are discussed.
Preparation of 5‐sulfonylpyrimidines from β‐keto, β‐cyano‐, and β‐ethoxycarbonyl‐β‐sulfonylenamines
Authors: Takahashi Masahiko , Mamiya Tsutomu , Wakao Makoto 
Published: March 2009

Abstractβ‐Keto‐β‐sulfonylenamines 2a,b reacted with benzamidine or guanidines to give 2,4‐disubstituted 5‐methanesulfonylpyrimidines 3a‐d, whose methanesulfonyl groups were substituted by n‐butyllithium or alkylmagnesium bromides to yield 2,4‐disubstitued 5‐alkylpyrimidines 6a‐d. 2‐Substituted 4‐amino‐5‐sulfonylpyrimidines 7a,b, 8 and 2‐substituted 5‐benzenesulfonylpyrimidin‐4‐ones 9a,b were similarly obtained from β‐cyano‐β‐sulfonylenamines 2c,d and β‐ethoxycarbonyl‐β‐sulfonylenamine (2e), respectively.
Synthesis and study of substituted coumarins. A facile preparation of D,L‐o‐tyrosine
Authors: Kokotos George , Tzougraki Chrysa 
Published: March 2009

AbstractA general procedure for the preparation of aminocoumarins and aminohydroxycoumarins under mild conditions is described. Amino‐ and acetamidoaminocoumarins were prepared by reduction of the corresponding nitro derivatives with sodium borohydride in the presence of 10% palladium on charcoal. Acid hydrolysis of the acetamidoaminocoumarins with (a) concentrated hydrochloric acid in ethanol, or (b) with 1Nhydrochloric acid under reflux, gave diaminocoumarins and aminohydroxycoumarins, respectively. Condensation of the ethyl ester of glycine with salicylaldehyde gave 3‐salicylideneaminocoumarin (XIII), the Schiff base of 3‐aminocoumarin (XII). Acid hydrolysis of XIII under the above mentioned conditions, (a) and (b), gave XII and 3‐hydroxycoumarin (XVI), respectively. Hydrogenation of compound XIII in dioxane or in dimethylformamide with 10% palladium on charcoal gave 3‐salicylaminocoumarin (XVII), while hydrogenation of XII, XIII or XVII in acetic acid with traces of water and palladium black gave the amino acido‐tyrosine.
Synthesis of 4‐heterocyclyl‐hexahydro‐8‐methoxyfuro[3,2‐c]quinolines by Lewis acid catalyzed [4 + 2]cycloaddition reaction
Authors: Kametani Tetsuji , Furuyama Hiroko , Fukuoka Yukari , Takeda Hajime , Suzuki Yukio , Honda Toshio 
Published: March 2009

AbstractSynthesis of 2‐substituted quinoline derivatives by Lewis acid catalyzed [4 + 2]cycloaddition was investigated.
Oxamates derived from 5‐aminopyrazoles
Authors: Peet Norton P. 
Published: March 2009

AbstractSeveral oxamates were prepared from ethyl oxalyl chloride and 5‐amino‐4‐cyanopyrazoles substituted in the 1‐position with aryl, aroyl and arylsulfonyl groups. Both aroyl and arylsulfonyl groups suffered chloride‐induced cleavage during this process. The synthesis of 7‐(6‐chloro‐3‐pyridazinyl)‐7H‐pyrazolo[3,4‐d]‐1,2,3‐tri‐azin‐4(3H)‐one (11) and its reaction with methanol to give 1‐(6‐chloro‐3‐pyridazinyl)‐5‐methoxy‐1H‐pyrazole‐4‐carboxamide (12) are also reported. A mechanism for this interesting transformation is presented.
Long chain heterocyclic dyes. Part one. Hydrophobic structures
Authors: Barni Ermanno , Savarino Piero , Larovere Raffaella , Viscardi Guido , Pelizzetti Ezio 
Published: March 2009

AbstractA series of polymethine dyes and of their precursors, containing long and short alkyl chains, was prepared and their chemical and spectroscopic (uv, 1H‐nmr) properties were briefly discussed. The electronic absorption spectra of the dyes in aqueous medium and in presence of anionic or cationic surfactants evidenced aggregation phenomena. The best deaggregating effect was shown by the anionic surfactant when added above its critical micellar concentration.
Benzocycloheptapyridines. Analogs of azatadine
Authors: Halczenko Wasyl , Shepard Kenneth L. 
Published: March 2009

AbstractCertain 3‐substituted derivatives of cyproheptadine (1a) have been shown to possess potent pharmacological properties. The structural analogy between cyproheptadine and azatadine (2) prompted the preparation of 9‐substituted derivatives of2and its 5,6‐dehydro analog for pharmacological comparison. The 9‐cyano and 9‐trifluoromethylthio derivatives were prepared by direct displacement of the corresponding 9‐bromo compounds. Acid hydrolysis of the nitriles generated the carboxylic acids. Oxidation of the trifluoromethylthio compounds15aand18agave the epoxy sulfones19aand19b, which could not be deoxygenated. Therefore, the trifluoromethylsulfonyl moiety was introduced prior to the formation of the exocyclic olefin.
Intramolecular capture of pummerer rearrangement intermediates. I. Synthesis of pyrrolo[2,1‐c][1,4]benzothiazines
Authors: Bates Dallas K. , Winters R. Thomas , Sell Burnell A. 
Published: March 2009

AbstractTreatment of 1‐(2‐alkylsulfinylphenyl)pyrroles with trifluoroacetic acid in refluxing toluene gives 4‐substituted pyrrolo[2,1‐c][1,4]benzothiazines in good yield when the alkyl group bears an electron withdrawing substituent on the α‐carbon. In the absence of such a group, starting material is recovered. The sulfoxides are prepared by oxidation (mCBPA) of the corresponding sulfide. The sulfides are prepared from 2‐aminobenzenethiol either by S‐alkylation followed by conversion to the pyrrole using 1,4‐dimethoxytetrahydrofuran in glacial acetic acid or by S‐alkylation of 1‐(2‐phenylmercapto)pyrrole followed by oxidation to the sulfoxide.
Synthesis of 1‐azapyrene
Authors: Tanga Mary J. , Reist Elmer J. 
Published: March 2009

AbstractThe environmental contaminants 1‐azapyrene 15, 2‐azapyrene 13 and several other azapyrene derivatives were synthesized from a common intermediate, 2,2a,3,4‐tetrahydrocyclopenta[cd]phenalen‐1‐one oxime 6. The synthesis of 1‐azapyrene 15 completes the series of azapyrenes.
The identification of 10 and 11 substituted 7H‐benzimidazo[2,1‐a]benz[de]isoquinolin‐7‐ones through 1N NOE studies on their methyl p‐toluenesulfonate salts
Authors: Campbell Jack B. , Lavagnino Edward R. , Paschal Jonathan W. 
Published: March 2009

AbstractThe spectral similarities of 10 and 11 substituted 7H‐benzimidazo[2,1‐a]benz[de]isoquinolin‐7‐ones hinder the identification of the individual isomers. Preparation of the 13‐methyl p‐toluenesulfonate salts of these compounds has allowed the assignment by the use of NOE techniques. Saturation of the N‐methyl caused an NOE at H‐12. The coupling pattern of H‐12 then provides identification of the compound.
Synthesis of [1,2,4]triazoloquinazolinones and imidazoquinazolinones
Authors: Murdoch Robert , Tully W. Roger , Westwood Robert 
Published: March 2009

Abstract4‐Quinazolinones have been cyclised to [1,2,4]triazoloquinazolinones and to imidazoquinazolinones. The direction of cyclisation has been proved by the unambiguous synthesis of their ethylation products.
Synthesis of 5H‐benzimidazo[1,2‐a][1,3,4]thiadiazolo[2,3‐d][1,3,5]triazin‐5‐one and 12H‐benzimidazo[1,2‐a]pyrimido[6,1‐d][1,3,5]triazin‐12‐one, two new heterocyclic ring systems
Authors: Bossio Ricardo , Marcaccini Stefano , Parrini Valerio , Pepino Roberto 
Published: March 2009

Abstract2‐(2,6‐Dimethylpyrimidin‐4‐ylaminobenzimidazole) (VIIa) and 2‐(1,3,4‐thiadiazol‐2‐ylamino)benzimidazole (VIIb) underwent a ring‐closure reaction with phosgene giving 1,3‐dimethyl‐12H‐benzirnidazo[1,2‐a]pyrirnido[6,1][‐d][1,3,5]triazin‐12‐one (IIa) and 5H‐benzimidazo[1,2‐a][1,3,4]thiadiazolo[2,3‐d][1,3,5]triazin‐5‐one (IIb) two hitherto unknown heterocyclic systems. A convenient synthesis of 2,6‐dimethyl‐4‐aminopyrimidine is described.
Synthesis of nitrogen‐containing heterocycles. 3. Formation and structure of new 1,2,4‐triazole derivatives
Authors: Miyamoto Yoshiko , Yamazaki Chiji 
Published: March 2009

AbstractTreatment of N(3)‐[(2‐cyano‐2‐ethoxycarbonyl)vinyl]amino‐N(4),N(4)‐dimethylaminomethylenehydrazones of aromatic carbonyl compounds with hot acetic acid resulted in the formation of symmetrical gem‐bis‐(3‐dimethylamino‐1,2,4‐triazol‐1‐yl)methanes, (3‐dimethylamino‐1,2,4‐triazol‐1‐yl)arylmethyl acetates, and (3‐dimethylamino‐1,2,4‐triazol‐1‐yl)alkenes of a gem‐diaryl type depending upon whether the carbonyl compound was aldehyde or ketone.
Synthesis of antimicrobial agents. IV. synthesis of 1‐hydroxypiperazine dihydrochloride and its applications to pyridone carboxylic acid antibacterial agents
Authors: Uno Toshio , Okuno Toshimi , Taguchi Masahiro , Iuchi Koji , Kawahata Yoshihiro , Sotomura Mikio , Tsukamoto Goro 
Published: March 2009

Abstract1‐Hydroxypiperazine dihydrochloride 7 was prepared and it was applied to the syntheses of new pyridone carboxylic acid antibacterial agents (PCA‐antibacterial agents). 1‐Cyclopropyl‐6,8‐difluoro‐1,4‐dihydro‐7‐(4‐hydroxypiperazin‐1‐yl)‐4‐oxoquinoline‐3‐carboxylic acid 13 showed the most potent antibacterial activity.
Electrochemical oxidation of 2,4,5‐triaryl‐substituted pyrroles. II. Oxidative dimerization of 4,5‐diphenyl‐2‐mesitylylpyrrole
Authors: Silvestri G. , Gambino S. , Filardo G. , Petruso S. , Caronna S. , Sprio V. 
Published: March 2009

Abstract2,4,5‐Triaryl‐substituted pyrroles lead, upon chemical or electrochemical oxidation, to an intermediate β‐β'‐dimer, which, in the course of the reaction, undergoes further oxidation to a tetracyclic derivative. To improve the selectivity towards the uncyclized dimer the oxidation of a triarylpyrrole in which the ortho positions of the phenyl group in position 2 are hindered by the presence of methyl groups was attempted. The cyclization was hindered, but an α‐β'‐dimer was obtained as the major product. An unexspected isomeric α‐β'‐dimer, in which the mesitylyl group is shifted into the β position of the pyrrole ring which undergoes the oxidation, was obtained in minor amounts. Electroanalytical data indicate that the process goes through the formation of a monomeric radical cation, followed by a slow chemical reaction.
Pyrazolo[3, 4‐d]pyrimidines related to lonidamine
Authors: Gatta Franco , Luciani Maria , Palazzo Giuseppe 
Published: March 2009

AbstractThis paper describes the synthesis of several pyrazolo[3, 4‐d]pyrimidines and tricyclic compounds with an imidazole, triazole or tetrazole ring fused to the pyrazolo[3, 4‐d]pyrimidine ring system, in an angular position (C‐4 and N‐5). All compounds reported herein contain the same substituent as “Lonidamine”, namely the 2, 4‐dichlorobenzyl group, attached to the pyrazole nucleus.
Synthesis and tautomeric behavior of 3‐(pyrazolylhydrazonomethyl)‐2‐oxo‐1, 2‐dihydroquinoxalines. Specification of hydrazone imine and diazenyl enamine forms
Authors: Kurasawa Yoshihisa , Kim Ho Sik , Yonekura Keiko , Takada Atsushi , Okamoto Yoshihisa 
Published: March 2009

Abstract3‐(Pyrazolylhydrazonomethyl)‐2‐oxo‐1, 2‐dihydroquinoxalines were synthesized, and their tautomer ratios between hydrazone imine and diazenyl enamine forms were specified by pmr spectral data.