bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hétérocycles à fonction quinone. 7. Benzo[f]quinazolinediones‐7,10 à action antitumorale potentielle
Authors: Parrot‐Lopez Hélène , Delacotte Jean‐Michel , Renault Jean , Cros Suzanne 
Published: March 2009

AbstractLes benzo[f]quinazolinediones‐7,10 4a‐c sont obtenues par oxydation par le nitrosodisulfonate de potassium (réactif de Frémy) des benzo[f]quinazolinamines correspondantes, préparées par réduction du dérivé nitré lui‐même obtenu à partir de la méthoxy‐8 2H‐benzo[f]quinazolinone‐1 (8). Le dérivé 4a présente une cytotoxicité non négligeable.
A reinvestigation of the synthesis of 3H‐[1,2]diazepino[5,6‐b]indoles. The synthesis of pyrido[4,3‐b]indoles
Authors: Karrick Gregory L. , Peet Norton P. 
Published: March 2009

AbstractRecently reported [1] syntheses of 6‐methyl‐1,2,4,5‐tetrahydro‐1,4‐dioxo‐3H[1,2]diazepino[5,6‐b]indole (5) and 4‐hydroxy‐6‐methyl‐3H[1,2]diazepino[5,6‐b]indole (12) were reinvestigated and shown to be in error. The correct assignments for these respective structures are 3‐amino‐1,9‐dihydro‐9‐methyl‐2H‐pyrido[4,3‐b]indol‐2,4(3H)‐dione (6) and 3‐amino‐3,9‐dihydro‐9‐methyl‐2H‐pyrido[4,3‐b]indol‐2‐one (13). Condensation of 6 and 13 with p‐nitrobenzaldehyde produced benzylidene derivatives, which confirmed the presence of the amino groups.
Alkaloids asymmetric synthesis from (S)‐pyroglutamic acid. II. Attempted asymmetric total synthesis of trans‐5‐ethyl‐2‐n‐heptylpyrrolidine
Authors: Marco José L. 
Published: March 2009

AbstractFrom the readily available (S)‐pyroglutamic acid 1 the asymmetric synthesis of trans and cis 5‐n‐heptyl‐2‐(S)‐hydroxymethylpyrrolidines 7, some derivatives and transformations are described.
Reaction of ketenes with N,N‐disubstituted α‐aminomethyleneketones. XVIII. Synthesis of N,N‐disubstituted 4‐amino‐3‐phenyl‐2H‐naphtho[1,2‐b]pyran‐2‐ones
Authors: Bargagna Alberto , Schenone Pietro , Longobardi Mario 
Published: March 2009

Abstract1,4‐Cycloaddition of phenylchloroketene to N,N‐disubstituted 2‐aminomethylene‐3,4‐dihydro‐1(2H)naphthalenones gave the corresponding adducts, namely N,N‐disubstituted 4‐amino‐3‐chloro‐3,4,5,6‐tetrahydro‐3‐phenyl‐2H‐naphtho[1,2‐b]pyran‐2‐ones II, in the case of aliphatic N,N‐disubstitution or aromatic N‐monosubstitution. Apart from IIf (NR2 = NMePh), adducts II were unstable and were dehydrochlorinated in situ with DBN to give N,N‐disubstituted 4‐amino‐5,6‐dihydro‐3‐phenyl‐2H‐naphtho[1,2‐b]pyran‐2‐ones III in fair overall yields. Compounds III were dehydrogenated with Pd/C in boiling p‐cymene to afford the title compounds generally in high yields.
Darstellung und eigenschaften trifluormethylmercapto‐substituierter pyrimidine
Authors: Haas A. , Lieb M. 
Published: March 2009

Abstract5‐Trifluoromethylthio‐substituted pyrimidines have been synthezised by halogenation of 5‐trifluoromethylthiouracile or barbituric acid with phosphorus halogenides POX3. The new compounds themselves are excellent starting materials for further nucleophilic exchange reactions. Thus fluoro‐, iodo‐, alkoxy‐ and aminoligands were introduced and further used for new synthesis. A new method for introducing trifluoromethylthio (SCF3)‐groups is presented.
Synthesis of thiophenedicarbonyldiazides and Di‐t‐butyl thiophendicarbamates
Authors: Galvez Carmen , Garcia Francisco , Garcia Juan , Soldevila Joan 
Published: March 2009

AbstractDicarbamates 1b and 1c, and dicarbonyldiazides 2b and 2c are obtained in good yields starting from thiophenedicarboxylic acids 3b and 3c, but the vicinal diacids 3a and 3d are not suitable for the synthesis of dicarbamates 1a and 1d and dicarbonyldiazides 2a and 2d; 1a is prepared by a stepway procedure previously described, and 1d by t‐butoxycarbonylation of the recently known 3,4‐thiophenediamine.
Acylation des β‐énaminoesters: Regio et stéréoformation des β‐énaminoesters N‐ ou C‐acylés
Authors: Brunerie Pascal , Célérier Jean‐Pierre , Petit Huguette , Lhommet Gérard 
Published: March 2009

AbstractLa taille du cycle des β‐énaminoesters cycliques oriente leur réaction avec les chlorures d'acides vers la formation sélective des dérivés N‐acylés pour les cycles à cinq chainons, et C‐acylés avec les cycles à sept chaînons; avec le cycle à six chainons on observe la formation d'un mélange de dérivés N et C‐acylés.
A novel and practical synthetic method of 3(2H)‐furanone derivatives
Authors: Sakai Takashi , Yamawaki Akitoshi , Ito Hiroshi , Utaka Masanori , Takeda Akira 
Published: March 2009

AbstractA novel, convenient synthetic method of 5‐atyl‐2,2‐dimethyl‐3(2H)‐furanones (aryl = C6H5, 2‐CH3C6H4, 3‐CH3C6H4, 4‐CH3C6H4, 2‐CIC6H4, 4‐CIC6H4, 2,4‐Cl2C6H3) is described. It involves the Claisen‐Schmidt condensation (potassium hydroxide/ethanol) of aromatic aldehydes with 3‐hydroxy‐3‐methyl‐2‐butanone to give enones, whose bromination followed by alkaline hydrolysis (sodium hydroxide/ethanol) affords 3(2H)‐furanone derivatives in 54–64% overall yields. The procedure is also applicable to nicotinaldehyde and furfural, although the yields are not satisfactory.
Benzannelated analogs of phenanthro[1,2‐b]‐ and [2,1‐b]thiophene: Synthesis and structural characterization by two‐dimensional NMR and X‐ray techniques
Authors: Stuart John G. , Quast Michael J. , Martin Gary E. , Lynch Vincent M. , Simonsen Stanley H. , Lee Milton L. , Castle Raymond N. , Dallas Jerry L. , John Boban K. , Johnson LeRoy F. 
Published: March 2009

AbstractSyntheses of benzo[3,4]phenanthro[1,2‐b]thiophene, benzo[3,4]phenanthro[2,1‐b]thiophene and their 1‐methyl analogs are reported as potential constituents of solvent refined coal liquids and for mutagenicity testing. The attempted synthesis of the 13‐methyl analogs which gave the 11‐methyl isomers is also described. Total assignments of the 1H‐ and 13C‐nmr spectra based on long range optimized heteronuclear protoncarbon two‐dimensional chemical shift correlation are reported. Carbon assignments obtained for benzo[3,4]‐phenanthro[1,2‐b]thiophene using this approach were confirmed with a 125 MHz 13C–13C INADEQUATE spectrum. X‐Ray crystal structures were determined for benzo[3,4]phenanthro[1,2‐b]thiophene and 1‐methyl‐benzo[3,4]phenanthro[2,1‐b]thiophene. Both molecules were helically distorted from planarity. Close intramolecular contacts between the bay region H1–H13 and ClMe‐H13 of 2.03 and 2.28 Å, respectively, were responsible for the distortions. There were no close intermolecular contacts of <3.5Å. both molecules refined to an R value of <0.05.
The chemistry of 4‐pyrimidinones: Acetylation and ring‐opening reactions
Authors: Sodum Rama S. , Klein Robert S. , Otter Brian A. 
Published: March 2009

Abstract4(3H)‐Pyrimidinone, as well as its 5‐acetoxy and 5‐methoxy derivatives, undergoes selective acetylation at N‐1 when treated with acetic anhydride. In the presence of water, these 1‐acetylpyrimidines undergo spontaneous covalent hydration at C‐2 and cleavage of the 1,2‐bond to give crystalline cis‐3‐acetylamino‐N‐formyl‐acrylamides, generally in good yield. In contrast, the 6‐methyl derivative of 4(3H)‐pyrimidinone forms an equilibrium mixture of acetylated products that undergo the ring opening process to only a very limited extent, the major product (11%) being the 3‐formylamino‐N‐acetylacrylamide derivative formed via N‐3 acetylation and cleavage of the 2,3‐bond.
Thermolyzed products of naphth[1,2‐d]imidazo[2,1‐b]‐thiazole‐2,3‐dione
Authors: Liu Kang‐Chien , Shih Bi‐Jane 
Published: March 2009

AbstractThemolysis of naphth[1,2‐d]imidazo[2,1‐b]thiazole‐2,3‐dione (1) in dimethylformamide gave an intermediate 2‐isocyanatonaphtho[1,2‐d]thiazole (2), which underwent [4 + 4] cyclodimerization to yield dinaphtho‐[1″,2″:4,5;1′″,2′″:4′,5′]dithiazolo[3,2‐a:3′,2′‐e]‐1,3,5,7‐tetrazocine‐9,19‐dione (3). The possible [4 + 2] cycloadduct, 3‐(2‐naphtho‐[1,2‐d]‐thiazolyl)naphtho[1′,2′:4,5]thiazolo[3,2‐a]‐1,3,5‐triazine‐2,4‐dione (4), an usual dimer type of heterocyclic isocyanates was not produced. Discrimination between the two isomers was established on the basis of spectral analyses.
Polycondensed nitrogen heterocycles. Part 21. Complete 13C NMR assignment of annelated phenanthridines
Authors: Cirrincione Girolamo , Dattolo Gaetano , Almerico Anna Maria , Aiello And Enrico , Cusmano Giuseppe , Macaluso Gabriella , Ruccia And Michele , Hinz Werner 
Published: March 2009

AbstractTwo‐dimensional nmr techniques were used for the complete assignment of 13C nmr spectra of pyrrolo‐[1,2‐f]‐, pyrazolo[1,5‐f]‐, and 1,2,4‐triazolo[1,5‐f]phenanthridines.
Crystal and molecular structures of cis‐1‐phenyl‐3‐piperidinocyclohexan‐1‐ol hydrochloride
Authors: Kimura Michio , Okabayashi Ichizo 
Published: March 2009

AbstractMr = 295.84, triclinic, Pl, a = 6.786(1), b = 7.658(1), c = 8.561(1) Å, α = 108.17(1), β = 97.94(1), γ = 103.32(2)°, V = 400.6 Å3, Z = 1,Dm = 1.23, Dx = 1.226 Mgm−3, δ(Cu Kα) = 1.5418 Å, μ = 20.81 cm−1, F(000) = 160. The structure has been solved by direct and Fourier methods and refined by a least‐squares procedure to the final R = 0.043 for 1182 observed reflections (|Fo] >3σ(Fo)). cis‐1‐Phenyl‐3‐piperidinocyclohexan‐1‐ol possessing 1,3‐diaxial positions between the piperidine and hydroxyl groups is converted to the isomer with 1,3‐diequatorial positions in its hydrochloride. The hydrogen bond is formed between the chloride anion and the protonated nitrogen atom of piperidine instead of the intramolecular hydrogen bond in the free cis‐base between the oxygen and nitrogen atoms.
Nitrogen bridgehead compounds. Part 65. Vilsmeier‐haack formylation of 4H‐pyrido[1,2‐a]pyrimidin‐4‐ones. Part 6
Authors: Horváth ÁGnes , Hermecz István 
Published: March 2009

Abstract2‐Substituted 3‐formyl‐4H‐pyrido[1,2‐a]pyrimidin‐4‐ones can be synthethized by Vilsmeier‐Haack formylation with the dimethylformamide‐phosphoryl chloride complex only from those 4H‐pyrido[1,2‐a]pyrimidin‐4‐ones which contain a substituent with electron‐releasing resonance effect in position 2. The products were characterized by uv, ir and 1H nmr spectroscopy.
Quinazolines and 1,4‐benzodiazepines. XCV. Synthesis of 1,4‐benzodiazepines by ring expansion of 2‐chloromethylquinazolines with carbanions
Authors: Walser A. , Flynn T. , Mason C. , Fryer R. Ian 
Published: March 2009

Abstract1,4‐Benzodiazepines bearing a carbon substituent at the 2‐position were obtained by reaction of 2‐chloromethylquinazoline 3‐oxides with stabilized carbanions. The carbanions of alkyl acetates, N,N‐disubstituted acetamides, acetonitrile, dimethylsulfone, N,N‐dimethyl methanesulfonamide and 2‐methylpyridine were successfully applied. The conversion of some of the 2‐carbon substituted 1,4‐benzodiazepines to imidazo[1,5‐a][1,4]benzodiazepines and [1,2,5]oxadiazino[5,4‐a][1,4]benzodiazepines is described.
Macrocyclic polyether‐ and polythioether‐diesters and dithioesters from 1,10‐phenanthroline‐2,9‐dicarboxylic acid
Authors: Chandler Christopher J. , Deady Leslie W. , Reiss James A. 
Published: March 2009

AbstractThe synthesis of nine macrocyclic polyether‐ and polythioether‐diesters 9–13 and dithioesters 14–17 derived from 1,10‐phenanthroline‐2,9‐dicarboxylic acid are reported. The macrocycles were prepared under conditions of high dilution in the absence of metal templates in consistently good yields and their structures were confirmed by 1H and 13C nmr spectroscopy. A macrocyclic phenanthroline‐pyridine tetraester 18 is also recorded.
An approach to tetrahydrobenz[b,d]pyrans and hexahydrophenanthridines by reaction of dilithiated phenol and aniline with pulegone
Authors: Pedaja Peter , Westerlund Christer , Hallberg Anders 
Published: March 2009

Abstract7,8,9,10‐Tetrahydro‐6,6,9‐trimethyldibenzo[b,d]pyran and 5,6,7,8,9,10‐hexahydro‐6,6,9‐trimethylphenanthridine have been prepared by reaction of pulegone with lithiumortho‐lithium phenolate and lithiumortho‐lithiumN‐trimethylsilylaniline. The cyclization into the annellated systems could be performed under essentially non‐acidic conditions.
Demethylation of crown ethers, aza crown ethers, and cryptands which have inward‐facing anisole units by lithium aluminum hydride in tetrahydrofuran
Authors: Czech Anna , Czech Bronislaw P. , Desai Dhimant H. , Hallman Johnny L. , Phillips John B. , Bartsch Richard A. 
Published: March 2009

AbstractLithium aluminum hydride in tetrahydrofuran is an efficient demethylating reagent combination for mono‐ and bicyclic polyether compounds which bear intra‐annular methoxyaryl groups.
2‐substituted 2,3‐dihydro‐5H‐thiazolo[2,3‐b]quinazoline derivatives
Authors: Georgiev Vassil St. , Bennett Grace A. , Radov Lesley A. , Kamp Dietgard K. , Trusso Laura A. 
Published: March 2009

AbstractThe synthesis of a series of 2‐substituted 2,3‐dihydro‐5H‐thiazolo[2,3‐b]quinazoline derivatives is described. Some of the title compounds exerted antiinflammatory and immunomodulating activities in laboratory animal models.
Preparation of 1,5‐disubstituted 4‐sulfonylpyrazoles, β‐cyano‐β‐sulfonylenamines and 5‐substituted 4‐sulfonylisoxazoles from β‐keto‐β‐sulfonylenamines
Authors: Takahashi Masahiko , Mamiya Tsutomu , Hasegawa Hisao , Nagai Takashi , Wakita Hideki 
Published: March 2009

AbstractReaction of β‐keto‐β‐sulfonylenamines 1a,b with N‐substituted hydrazines gave 1,5‐disubstituted 4‐sulfonylpyrazoles 2a‐h in moderate yields, which were ring‐opened on treatment with n‐butyllithium to afford β‐cyano‐β‐sulfonylenamines (3a,b,d‐f). 5‐Substitued 4‐sulfonylisoxazoles 6a‐d were also prepared from 1a‐d and hydroxylamine.
Polycondensed nitrogen heterocycles. Part 19. Pyrrolo[1,2‐f]phenanthridines by pschorr‐type cyclization brought about by hypophosphorous acid
Authors: Dattolo Gaetano , Cirrincione Girolamo , Almerico Anna Maria , Aiello Enrico , D'Asdia Isabella 
Published: March 2009

AbstractPyrrolo[1,2‐f]phenanthridines were prepared in good yields by the diazotization in acetic acid of the amines la,b and subsequent treatment with hypophosphorous acid. The necessity for hypophosphorous acid in the reaction was demonstrated.
Synthesis of 3‐(α‐chlorophenylhydrazono)heteroarylmethyl‐2‐oxo‐1,2‐dihydroquinoxalines with antimicrobial activity
Authors: Kurasawa Yoshihisa , Muramatsu Muneto , Yamazaki Kaoru , Okamoto Yoshihisa , Takada Atsushi 
Published: March 2009

AbstractThe reactions of 3‐(α‐chlorophenylhydrazono)hydrazinocarbonylmethyl‐2‐oxo‐1,2‐dihydroquinoxalines 4a,c with triethyl orthoesters resulted in the intramolecular cyclization to give the 3‐(α‐chlorophenylhydrazono‐1,3,4‐oxadiazol‐2‐ylmethyl)‐2‐oxo‐1,2‐dihydroquinoxalines 5a‐d, but not the 1,2,4,5‐tetrazepinylquinoxalines 6a‐d. The cyclization mode into the 1,3,4‐oxadiazole ring was confirmed by the alternate syntheses of 5a,c from the reactions of the 3‐(1,3,4‐oxadiazol‐2‐ylmethylene)‐2‐oxo‐1,2,3,4‐tetrahydroquinoxalines 7a,b with o‐chlorobenzenediazonium chloride. Moreover, the reactions of 3‐(benzimidazol‐2‐ylmethylene)‐2‐oxo‐1,2,3,4‐tetrahydroquinoxaline hydrochloride 8 with o‐, m‐ and p‐chlorobenzenediazonium chlorides afforded the 3‐(α‐chlorophenylhydrazonobenzimidazol‐2‐ylmethy])‐2‐oxo‐1,2‐dihydroquinoxa]ine hydrochlorides 9a‐c, respectively. Compounds 5a‐d and 9a‐c were found to exhibit antimicrobial activities.
Methylx derivatives of tetrahydrobenzo‐ and benzofurocoumarins, a new class of potential photoreagents toward dna
Authors: Rodighiero P. , Palumbo M. , Magno S. Marciani , Manzini P. , Gia O. , Piro R. , Guiotto A. 
Published: March 2009

AbstractA number of new tetracyclic furocoumarin derivatives with a linear structure or with various angular arrangements, were synthetized. The new compounds are characterized for having an additional cyclohexene or phenyl ring condensed at the 4′,5′ double bond of the furan ring of the furocoumarin nucleus. The syntheses were performed starting from the appropriate hydroxycoumarins on which the tetrahydrobenzofuran or benzofuran moiety was built. Methyl groups have been introduced into positions which look most promising for enhancement of the photoreactivity of the compounds toward DNA.
The crystal structure of 3a,4,5,6‐tetrahydro‐3a,5,5‐trimethyl‐1,3‐diphenyl‐3H‐1,2,4‐triazolo[4,3‐a][1,5]benzodiazepine
Authors: Aversa M. C. , Ferlazzo A. , Giannetto P. , Kohnke F. H. , Slawin A. M. Z. , Williams D. J. 
Published: March 2009

AbstractThe crystal structure of the title compound is described.
Synthesis and biological activity of bridgehead nitrogen heterocycles
Authors: Goswami B. N. , Kataky J. C. S. , Baruah J. N. 
Published: March 2009

AbstractThe reaction of 3‐(2,4‐dichlorophenyl)‐5‐mercapto 1,2,4–1H‐triazole with α‐haloketones and with 1,2‐dibromoethane leading to the formation of fused heterocycles were carried out and the orientation of cyclization was studied. The reaction of 3‐(2,4‐dichlorophenyl)‐5‐mercapto‐4‐amino‐1,2,4‐s‐triazole with α‐haloketones
Applications of 1‐alkoxycarbonyl‐ and 1‐acyl‐v‐triazolo[4,5‐b]pyridines as acylating reagents
Authors: Torrini Ines , Zecchini Giampiero Pagani , Agrosì Francesco , Paradisi Mario Paglialunga 
Published: March 2009

AbstractSelective N‐protection of hydroxyamino esters has been readily achieved using 1‐alkoxycarbonyl‐ or 1‐acyl‐v‐triazolo[4,5‐b]pyridines. The amide‐type triazolides reacted with alcohols in the presence of DBU at room temperature to afford in high yields the corresponding esters. The different reactivity of 1‐ and 3‐alkoxycarbonyl derivatives of the title bicyclic system toward primary amines has been further investigated.
Furopyridines. VI. Preparation and reactions of 2‐ and 3‐substituted furo[2,3‐b]pyridines
Authors: Morita Hiroyuki , Shiotani Shunsaku 
Published: March 2009

AbstractThis paper describes the synthesis and chemical properties of some 2‐ and 3‐substituted furo[2,3‐b]pyridines. Reaction of ethyl 2‐chloronicotinate 1 with sodium ethoxycarbonylmethoxide or 1‐ethoxycarbonyl‐1‐ethoxide gave β‐keto ester 2 or ketone 5, respectively. Ketonic hydrolysis of 2 afforded ketone 3, from which furo[2,3‐b]pyridine 4 was obtained by the method of Sliwa. While, 2‐methyl derivative 7 was prepared from 5 by reduction, O‐acetylation and the subsequent pyrolysis. Reaction of ketone 3 with methyllithium gave tertiary alcohol 8 which was O‐acetylated and pyrolyzed to give 3‐methyl derivative 9. Formylation of 4, via lithio intermediate, with DMF yielded 2‐formyl derivative 10, from which 7, was obtained by Wolff‐Kishner reduction. Dehydration of the oxime 11 of 10 gave 2‐cyano derivative 12, which was hydrolyzed to give 2‐carboxylic acid 13. Reaction of 3‐bromo compound 14 with copper(I) cyanide gave 3‐cyano derivative 15. Alkaline hydrolysis of 15 afforded compound 16 and 17, while acidic hydrolysis gave carboxamide 18. Reduction of 15 with DIBAL‐H afforded 3‐formyl derivative 19. Wolff‐Kishner reduction of 19 gave no reduction product 9 but hydrazone 20. Reduction of tosylhydrazone 21 with sodium borohydride in methanol afforded 3‐methoxymethylfuro[2,3‐b]pyridine 22.
Heteroannulated‐9,10‐anthracenediones. The synthesis of substituted 5‐ and 7‐chloroanthra[1,9‐cd]pyrazol‐6(2H)‐ones, precursors to anticancer anthrapyrazoles
Authors: Showalter H. D. Hollis , Johnson Judith L. , Hoftiezer Jeanne M. 
Published: March 2009

AbstractSynthetic methodologies to a number of 5‐ and 7‐chloroanthra[1,9‐cd|pyrazol‐6(2H)‐ones, 4 and 37 respectively, optionally substituted with side chains at N‐2 and dioxy substituents in the A ring, are reported. Reported also are detailed uv, ir and 1H‐nmr spectroscopy for representative compounds.
Synthesis of furazano‐substituted 1,5‐diazepines
Authors: Fischer John W. , Atkins Ronald L. , Nissan Robin A. , Lowe‐Ma Charlotte K. , Decker David L. 
Published: March 2009

AbstractA series of furazano‐substituted 1,5‐diazepines have been synthesized from the reaction of a methyl ketone and 3,4‐diaminofurazan in the presence of a mild Lewis acid. The reaction was found to be regiospecific. Other ketone substrates also yielded diazepines, however, these products were found to be unstable and decomposed upon contact with air.
Synthesis of 4‐Aryl‐1,4‐dihydro‐2,6‐bis(trifluoromethyl)‐3,5‐pyridinedicarboxylates
Authors: Kim Dong H. 
Published: March 2009

AbstractTreatment of 4‐aryl‐2,6‐dihydroxy‐2,6‐bis(trifluoromethyl)‐3,5‐piperidinedicarboxylic acid esters with phosphorus oxychloride in pyridine afforded 4‐aryl‐1,4‐dihydro‐2,6‐bis(trifluoromethyl)‐3,5‐pyridine dicarboxylic acid esters which were reported originally by Balicki and Nantka‐Namirski, but were later proven to be 4‐aryl‐2,6‐dihydroxy‐2,6‐bis(trifluoromethyl)‐3,5‐piperidine dicarboxylic acid esters.
Synthesis of 6‐phenyl and 6‐styrylthiazolo[3,2‐b] [1,2,4]triazoles
Authors: Hénichart Jean‐Pierre , Houssin Raymond , Bernier Jean‐Luc 
Published: March 2009

AbstractThiazole rings have been often encountered in the structure of antibiotic or antitumor drugs. An easy synthesis of them has revealed itself necessary in order to elucidate the mechanism of action of these naturally occurring substances. A method of preparation of conjugated b‐ethylenic thiazole[3,2‐b] [1,2,4]triazoles by heating a 3‐thio substituted [1,2,4]triazole in the presence of polyphosphoric acid is reported here, giving the expected product in a 60% yield.
Synthesis and reaction of 5‐amino‐3‐trifluoromethylisoxazole and ‐pyrazole‐4‐carboxylic acids
Authors: Tanaka Kiyoshi , Suzuki Takashi , Maeno Seiji , Mitsuhashi Keiryo 
Published: March 2009

Abstract5‐Amino‐3‐trifluoromethylisoxazole‐ and ‐pyrazole‐4‐carboxylic acids were prepared by the reactions ot trifluoroacetonitrile oxide or ‐imines with cyanoacetic acid derivatives, respectively. The behavior of thus obtained aminoazole‐4‐carboxylic acids toward some electrophiles was examined. In acylation with acyl chlorides, the aminoisoxazole‐4‐carboxylate 2a was diacylated to give the (diacylamino)isoxazole‐4‐carboxylate 7, whereas the analogous aminopyrazole 5a produced the cyclized pyrazolooxazinone 13. Moreover, carbamoylation of 2a with isocyanates gave the trifluoromethylisoxazolouracils 10.
3,3′‐diaryl‐5‐morpholino‐4,5,4′,5′‐tetrahydro‐4,5′‐spirobi[isoxazoles]. Synthesis by cycloaddition reactions and substituent effect on the cycloaddition kinetics
Authors: Beltrame Paolo , Gelli Gioanna 
Published: March 2009

Abstract3‐Aryl‐4‐methylene‐5‐morpholino‐4,5‐dihydroisoxazoles 1a‐e were synthesized; fifteen different 3,3′‐diaryl‐5‐morpholino‐4,5,4′,5′‐tetrahydro‐4,5′‐spirobi[isoxazoles] 3 were obtained by their reaction with some stable aryl nitrile oxides. The spiro‐derivatives were characterized by their nmr spectra. Kinetic measurements showed that substituents on the nitrile oxide have a weak effect on the cycloaddition rate (Hammett 'p = ca 0.3), while substituents on the dipolarophile have no effect at all.
The Synthesis of pyrimido[4,5‐b][1,4]diazocines and pyrido[2,3‐b][1,4]diazoeines
Authors: Thompson Michael D. 
Published: March 2009

AbstractThe reaction conditions for the preparation of 7H,8H‐1,3‐dimethyl‐2,4,6,9‐tetraoxopyrimidino[4,5‐b][1,4]‐diazocine (9), 1,3‐dimethy 1–2,4,6,11‐tetraoxobenzo[f]pyrimidino[4,5‐b][1,4]diazocine (10), 7H,8H‐1,3‐dimethyl‐2,4,6,10‐tetraoxopyrimidino[4,5‐b][1,4]diazonine (16), and 7H,8H‐6,9‐dioxopyridino[2,3‐b][1,4]diazocine (19) were determined. The mechanism of the formation of these compounds was established. The scope of these reactions was found to be general for eight and nine ring formation from 2,3‐diamino‐N‐heterocycles.
Pyrrolopyridine analogs of nalidixic acid. 1. Pyrrolo[2,3‐b]pyridines
Authors: Toja Emilio , Tarzia Giorgio , Ferrari Pietro , Tuan Giorgio 
Published: March 2009

AbstractA series of 4,7‐dihydro‐4‐oxo‐1H‐pyrrolo[2,3‐b]pyridine‐5‐carboxylic acids was synthesized from ethyl 5‐methyl(or 5H)‐2‐aminopyrrole‐3‐carboxylate. The starting pyrroles were obtained by reaction of carbethoxyacetamidine with bromoacetone or chloroacetaldehyde. One compound (10) showed antibacterial activity in vitro.
Definitive assignment of 13C NMR signals in tryptophan and related molecules
Authors: Morales‐Ríos M. S. , Joseph‐Nathan P. 
Published: March 2009

AbstractSelective photodeuteration of carboxyltryptamines at C‐4 allowed to settle the controversy about the 13C nmr assignment of C‐4, C‐5 and C‐6, which for tryptophan are definitively assigned at 118.4, 118.2 and 120.6 ppm, respectively.