bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of 5,6‐dimethoxyquinazolin‐2(1H)‐ones
Authors: Press Jeffery B. , Bandurco Victor T. , Wong Elizabeth M. , Hajos Zoltan G. , Kanojia Ramesh M. , Mallory Robert A. , Deegan Edward G. , Mcnally James J. , Roberts Jerry R. , Cotter Mary Lou , Graden David W. , Lloyd John R. 
Published: March 2009

AbstractSynthesis of 5,6‐dimethoxyquinazolin‐2(1H)‐one derivatives was the subject of investigations leading to the preparation of title compounds 11, 13, 14 and 26. Target quinazolines 1 were synthesized in three ways; the route starting from o‐vanillin via the intermediacy of 6‐amino‐2,3‐dimethoxyacetophenone (19) was used for most of the preparative work. The unexpected formation of an acid‐labile dimer of 13 was discovered and solid state 13C nmr was used for structural assignment. The 5‐methoxy substituent in these systems shows anomalous spectral characteristics and, in one case, was cleaved in acid media to 22.
Conversion of 4‐amino‐1H‐1,5‐benzodiazepine‐3‐carbonitrile to pyrazolo[3,4‐d]pyrimidines, pyrimido[1,6‐a]benzimidazole, and pyrazolo[3′,4′:4,5]pyrimido[1,6‐a]benzimidazoles
Authors: Okamoto Yoshihisa , Togo Isao , Kurasawa Yoshihisa , Takagi Kaname 
Published: March 2009

AbstractThe reactions of multifunctional compounds 2a, b, c, 3a, b and 4a, b which were readily obtained from 4‐amino‐1H‐1,5‐benzodiazepine‐3‐carbonitrile 1 with orthoesters are described, and derivatives of pyrazolo‐[3,4‐d]pyrimidines 5, pyrimido[1,6‐a]benzimidazole 9, and pyrazolo[3′,4′:4,5]pyrimido[1,6‐a]benzimidazole 10 are synthesized.
A facile synthesis of 5,7‐dihydro‐5‐oxopyrido[3′,2′:5,6]pyrimido[1,2‐a]benzimidazoles. A new heterocyclic ring system
Authors: Caroti Paola , Ceccotti Carlo , Da Settimo Antonio , Palla Fabio , Primofiore Giampaolo 
Published: March 2009

AbstractReaction between 2‐chloropyridine‐3‐carbonyl chloride and 1‐alkyl‐2‐aminobenzimidazoles afforded the N‐(1‐alkylbenzimidazole‐2‐yl)‐2‐chloropyridine‐3‐carboxamides, which were cyclized to 5,7‐dihydro‐5‐oxopyrido[3′,2′:5,6]pyrimido[1,2‐a]benzimidazoles. The assigned structures of these hitherto unknown heterocyclic compounds were confirmed by their ir and 1H nmr spectra and chemical evidence.
Synthesis and reactions of 3‐iodo‐4H‐pyran‐4‐ones
Authors: Marei Mohamed Gaber , Mishrikey Morcos Michael , El‐Kholy Ibrahim El‐Sayed 
Published: March 2009

Abstract3‐Iodo‐4H‐pyran‐4‐ones have been synthesised in excellent yield by the reaction of acetylenic β‐diketones with iodine monochloride and were converted into the corresponding 4H‐pyran‐4‐thiones. The iodopyrones and thiopyrones gave with methylamine the respective N‐methylpyridones and thiopyridones. The structure of the above compounds was confirmed from their spectral characteristics.
Heterocyclen aus α‐nitroolefinen. XII . 3‐Acetyl‐4,5‐dihydro‐5‐(methylenamino)furane und 3‐acylpyrrole aus α‐nitroolefinen und β‐diketonen
Authors: Boberg Friedrich , Garburg Karl‐Heinz , Görlich Karl‐Joachim , Pipereit Eberhard , Redelfs Elke , Ruhr Maria 
Published: March 2009

AbstractFrom α‐nitroolefines 1 and β‐diketones 2 3‐acetyl4,5‐dihydro‐5‐(methy1eneamino)furans 5 are prepared. Furans 5 react in acid medium to yield 1‐unsubstituted 3‐acylpyrroles 6, catalytic hydrogenation yields 1‐substituted 3‐acylpyrroles 9. The 1H‐nmr and 13C‐nmr investigations prove the constitutions.
Syntheses and configurations of some heterocyclic amidoximes. X‐Ray crystal structure of 3‐phenyl‐5,6‐dihydro‐2(1H)‐pyrazinone‐O‐methyloxime
Authors: Johnson James Elver , Maia Joanne A. , Tan Karen , Ghafouripour Abdolkarim , De Meester Patrice , Chu Shirley S. C. 
Published: March 2009

AbstractO‐Methyl‐α‐ketophenylacetohydroximoyl chloride (1) was prepared by the reaction of O‐methyl‐α‐methoxyphenylacetohydroximoyl chloride (5) with N‐bromosuccinimide and concentrated hydrobromic acid. Reaction of 1 with ethylenediamine gave 3‐phenyl‐5,6‐dihydro‐2(1H)‐pyrazinone‐O‐methyloxime (6). 3‐Phenyl‐5,6‐cyclohexano‐5,6‐dihydro‐2(1H)‐pyrazininone‐O‐methyloxime (7) was prepared by reaction of 1 with trans‐1,2‐diaminocyclohexane. The X‐ray structure of 6 has been determined. The crystals are orthorhombic, space group Pbca with a = 10.264(3), b = 18.262(4), c = 23.530(4)Å, V = 4411(2)Å3, and Z = 16. The structure, which was refined to R = 0.038 using 1652 observed reflections, shows the amidoxime moiety to be the Z configuration. Reaction of benzohydroximoyl chloride with aziridine gave (Z)‐aziridinylbenzaldoxime (16a). Ultraviolet irradiation of a benzene solution of 16a gave a mixture of the Z and E isomers 16a and 16b. The E isomer 16b underwent thermal isomerization to 16a at 100°. Reaction of 16a with dimethyl sulfate in sodium hydroxide solution gave (Z)‐O‐methylaziridinylbenzaldoxime (17a). Photoisomerization of a hexane solution of 17a gave a mixture of the Z and E isomers 17a and 17b which were separated by preparative glc. The isomers 17a and 17b are resistant to thermal Z = E isomerization. The mechanisms of thermal isomerization of benzamidoximes are discussed.
2‐Metylthiazolium salts as 1,4‐dinucleophiles. Thiazolo[3,2‐a]pyridinium salts from westphal condensation
Authors: Galera C. , Vaquero J. J. , Navio J. L. Garcia , Alvarez‐Builla J. 
Published: March 2009

AbstractCondensation of 2‐methylthiazoliura salts with 1,2‐dicarbonyls in the presence of base, yielded thiazolo‐[3,2‐a]pyridinium derivatives. Results with different substrates are discussed.
Reaction of pyrazine‐2,3‐dicarbonitrile and 1,3‐dimethyllumazine with alkyl radicals
Authors: Tada Masaru , Ito Takayori , Ohshima Kaoru 
Published: March 2009

AbstractPyrazine‐2,3‐dicarbonitrile (1) reacts with alkyl radicals to give mono‐ 3 and di‐alkylated pyrazine‐2,3‐dicarbonitriles 4. Similarly 1,3‐dimethyllumazine (2) reacts with alkyl radicals to give 7‐alkyl‐1,3‐dimethyllumazines 8 as the major product. The reactivity of alkyl radicals decreases in the order tertiary, secondary, and primary, and 1 is more reactive than 2 in those radical substitution reactions.
Beckmann rearrangement of (+)‐3‐methoxy‐17‐methylmorphinan‐10‐one oxime
Authors: Mohacsi Erno 
Published: March 2009

Abstract(+)6,7,7a,8,9,10,11,11a‐Octahydro‐2‐methoxy‐12‐methyl‐5H‐7,11a‐irninoethanodibenz[c, e]azepin‐5‐one (3) was prepared by Beckmann rearrangement of the oxime of (+)‐3‐methoxy‐17‐methylmorphinan‐10‐one (2) with polyphosphoric acid.
Syntheses of 1,3,8,10,12‐pentazanaphthacene‐2,4,7,9‐(12H,3H,8H,10H)‐tetraones (linear pyrimidine‐fused 5‐deazaflavins), 1,3,6,8,12‐pentazabenz[a]anthracene‐2,4,7,9(12H,3H,6H,8H)‐tetraones(bent pyrimidine‐fused 5‐deazaflavins), and their flavin analogs
Authors: Yoneda Fumio , Koga Masakazu 
Published: March 2009

Abstract1,3,8,10,12‐Pentazanaphthacene‐2,4,7,9(12H,3H,8H,10H)‐tetraones (linear pyrimidine‐fused 5‐deazaflavins) and 1,3,6,8,12‐pentazabenz[a]anthracene‐2,4,7,9(12H,3H,6H,8H)‐tetraones (bent pyrimidine‐fused 5‐deazaflavins) were synthesized by condensation of 7‐alkylaminoquinazoline with 6‐chloro‐5‐formyl‐3‐methyluracil. Also, their flavin analogs, 1,3,5,8,10,12‐hexazanaphthacene‐2,4,7,9(12H,3H,8H,10H)‐tetraones (linear pyrimidine‐fused flavins) and l,3,5,6,8,12‐hexazabenz[a]anthracene‐2,4,7,9(12H,3H,6H,8H)‐tetraones (bent pyrimidine‐fused flavins) were synthesized by cyclization of 7‐[N‐alkyl‐N‐(5‐nitrouracil‐6‐yl)]aminoquin‐azolines with the Vilsmeier reagent.
A simple synthesis of a new family of polycyclic oxygen containing heterocycles
Authors: Geoffrey Philippe , Carre Marie‐Christiane , Caubere Paul , Ianelli Sandra , Nardelli Mario 
Published: March 2009

AbstractBenzocyclobutenols 1 were transposed by boron trifluoride etherate in the presence of triethylsilane into a new family of heterocycles 2.
Spirocyclization of 1‐(o‐aminophenyl)cycloalkanols and 1‐(2′‐amino‐3′‐pyridinyl)cycloalkanols
Authors: Canonne Persephone , Boulanger Raynald , Chantegrel Bernard 
Published: March 2009

AbstractA one‐step synthesis of spiro[cycloalkane‐1,4′‐2H‐3′,1‐benzoxazin]‐2′‐ones and spiro[cycloalkane‐1,4′‐1H‐pyrido[2′,3′‐d][1,3′]oxazin]‐2′‐ones, obtained in good yield from the corresponding 1‐(o‐aminophenyl) and 1‐(2′‐amino‐3′‐pyridinyl)cycloalkanols is described using ethyl carbonate in presence of n‐butyllithium.
Novel chromophoric heterocycles based on maleimide and naphthoquinone
Authors: Katritzky Alan R. , Fan Wei‐Qiang , Li Qiao‐Ling , Bayyuk Shibli 
Published: March 2009

Abstract1‐Phenyl‐3,4‐dichloromaleimide, 1‐n‐propyl‐3‐bromomaleimide, and 2,3‐dichloro‐1,4‐naphthoquinone have been condensed with various mono‐ and bis‐nucleophiles to yield a range of novel dyes and pigments. Their visible absorption spectra are discussed.
Synthesis of 2,2,4‐trisubstituted‐1,2‐dihydroquinazolines
Authors: Strekowski Lucjan , Cegla Marek T. , Kong Suk‐Bin , Harden Donald B. 
Published: March 2009

AbstractSynthesis of 2,2,4‐trisubstituted‐1,2‐dihydroquinazolines 6 from readily available 2‐aminobenzonitrile (1) is described. The scope and limitations of the method are discussed.
Pyridazines. XLI synthesis of novel pyrido[3,4‐d]pyridazine derivatives from 4,5‐disubstituted pyridazines
Authors: Boamah Philip Yaw , Haider Norbert , Heinisch Gottfried 
Published: March 2009

AbstractPyrido[3,4‐d]pyridazines 2–5, 21 bearing one, two, or three aryl substituents in the pyridine moiety are shown to be conveniently accessible from 4‐aroyl‐5‐methylpyridazines or 4,5‐diaroylpyridazines, respectively, by condensation reactions with appropriate C‐N fragments. In addition, the novel pyridazine‐annelated pyridones 24, 25 were found to be easily available from ethyl 5‐methyl‐4‐pyridazinecarboxylate.
Mitt. XV: Struktur und reaktivität von isoanellierten heterocyclischen systemen mit 4nπ‐ und (4n + 2) π‐elektronen. 2‐t‐butyl‐4‐methyl‐2,4‐dihydropyrrolo[3,4‐b]indole. reaktionen mit aktivierten CC‐dienophilen
Authors: Dyker Gerald , Kreher Richard P. 
Published: March 2009

AbstractReactions of 2‐t‐butyl‐4‐methyl‐2,4‐dihydropyrrolo[3,4‐b]indoles with N‐aryl‐maleimides have been investigated. The formation of 1:1‐cycloadducts is influenced by substituents at 1,3‐position. The consecutive transformations of these intermediates can be controlled by nucleophilic solvents or reagents. Ring opening reactions occur at the labile N,O‐acetal group of the cycloadducts followed by eliminaton or addition reactions.
The chemistry of 2H‐3,1‐benzoxazine‐2,4(1H)‐dione (isatoic anhydride). 21. a mild process for the preparation of 10‐alkyl‐9‐acridanones and it's application to the synthesis of acridone alkaloids
Authors: Coppola Gary M. , Schuster Herbert F. 
Published: March 2009

Abstract10‐Substituted‐9‐acridanones are readily prepared by the reaction of the corresponding isatoic anhydride with the lithium enolate of 2‐cyclohexen‐1‐one. The initially formed product, the 1,2‐dihydroacridone need not be purified but can be aromatized directly with DDQ to the desired acridone. This methodology is applicable to the synthesis of acridone natural products. Two alkaloids, 1,2,3‐trimethoxy‐10‐methylacridone (9) and evoxanthine (10), were prepared from 4,5,6‐trimethoxy‐N‐methylisatoic anhydride and 6‐methoxy‐4,5‐methyl‐enedioxy‐N‐methylisatoic anhydride respectively. In these trioxygenated systems, palladium‐on‐charcoal must be used to aromatize the penultimate intermediate.
Synthesis, structural and conformational study of some esters derived from 8‐phenethyl‐8‐azabicyclo[4.3.1]decan‐10α‐ol
Authors: Gálvez E. , Arias M. S. , Rico B. , Ardid I. , Florencio F. , Sanz J. 
Published: March 2009

AbstractA series of 10α‐acyloxy‐N‐phenethyl‐8‐azabicyclo[4.3.1]decane derivatives have been synthesized and studied by 1H and 13C nmr spectroscopy, and the crystal structure of N‐phenethyl‐10aL‐(xanten‐9″‐carbonyloxy)bicyclo[4.3.1]decane 2 has been determined by X‐ray diffraction. The compounds studied display in deuteriochloroform the same preferred conformation adopted by the piperidine ring as a distorted chair conformation flattened at N‐8 with both the phenethyl and acyloxy groups in the equatorial position with respect to the piperidine ring. These results are in close agreement with that found for compound 2 in the crystalline state.
1,3‐Dipolar cycloaddition reactions. Regioselective synthesis of heterocycles and theoretical studies
Authors: Pierini Adriana B. , Cardozo Mario G. , Montiel Aida A. , Albonico Sem M. , Pizzorno Maria T. 
Published: March 2009

AbstractWe report a 1,3‐dipolar cycloaddition reaction between a oxazolium 5‐oxide derivative with chloroacrylonitrile or ethyl propiolate as dipolarophiles, in order to obtain substituted pyrrolizidines. Experimentally we found that the reaction is regiospecific with chloroacrylonitrile and regioselective with ethyl propiolate. The secondary attractive orbital interactions from the Frontier Molecular Orbital Theory, the differences in stability of the possible biradical intermediaries postulated for the reaction and some hindrance effects, explain the regioselectivity observed experimentally.
Synthèse de dimethyl‐2,2 chromannediones‐3,4: Condensation avec les ortho‐diaminopyridines
Authors: Vinot Nicole , Maitte Pierre 
Published: March 2009

AbstractLes diméthyl‐2,2 chromannediones ont été préparées par oxydation des chromanones correspondantes à l'aide du nitrite d'isoamyle. Dans la majorité des cas, les monocétones sont elles‐měmes obtenues par action de l'acide méthyl‐3 butène‐2 oïque sur un phénol substitué, en présence d'acide polyphosphorique. La condensation des chromannediones avec les orthodiaminopyridines permet d'obtenir des benzopyrannopyridopyrazines qui, du fait de la dissymétrie des réactifs, sont le plus souvent un mélange d'isomères.
Pyrrolo[1,4]benzodiazepines. IV. Synthesis of E‐ and Z‐5,11‐dioxo‐11a‐ethoxycarbonyl‐2‐ethylidene‐1,2,3,10,11,11a‐hexahydro‐5H‐pyrrolo[2,1‐c][1,4]benzodiazepine
Authors: De Caprariis P. , De Martino G. , Abignente E. , Avara P. , Mayol L. 
Published: March 2009

AbstractPreparation of the title compound starting from 4‐acetyl‐2,2‐diethoxycarbonyl‐2,3‐dihydro‐1‐(2‐nitro‐benzoyl)‐1H‐pyrrole by selective reduction is described; its E and Z forms were isolated and their geometrical structure assigned on the basis of 1H and 13C nmr spectral data.
Synthesis of potential antifilarial agents 2 . methyl 2‐substituted purine 8‐carbamates and related compounds
Authors: Ram Siya , Evans William , Wise Dean S. , Townsend Leroy B. , Mccall John W. 
Published: March 2009

AbstractA series of methyl 2‐substituted purine 8‐carbamates was prepared and evaluated for antifilarial activity. These purines were synthesized as aza congeners of benzimidazole carbamates which have shown significant anthelmintic activity to determine the effect that this modification might have on anthelmintic activity. The compounds were tested against the filarial infection, B. pahangi, in jirds. None of the compounds prepared in this study demonstrated antifilarial activity.
Novel diphenysulphapyrimidine acetates derived from chalcones
Authors: Usifoh C. O. , Olugbade T. A. , Onawumi G. O. , Oluwadiya J. O. , Reisch J. 
Published: March 2009

AbstractCyclocondensation of sulphaguanidine acetate with chalcones in dimethylsulphoxide at 110° gave 4,6‐diphenylsulphapyrimidine acetates.
Synthesis of 3,4,5‐triamino‐4H‐1,2,4‐triazole (guanazine) and its 4‐arylideneamino derivatives
Authors: Emilsson Håkan 
Published: March 2009

AbstractSynthetic methods for the preparation of 3,4,5‐triamino‐4H‐1,2,4‐triazole (guanazine) and its 4‐arylidene‐amino derivatives are described. Guanazine, which can be used as an appropriate starting material in the syntheses of different bicyclic heterocycles, was readily obtained from thiosemicarbazide by treatment with mercuric oxide. Guanazine was also obtained from the S‐methylisothio ether of thiosemicarbazide via a pyrolytic reaction. The 4‐arylideneamino derivatives were either prepared by treatment of guanazine with an appropriate aromatic aldehyde, or by methods in which 1‐arylidene‐5‐thiocarbamoyldiaminoguanidines are used as starting materials.
Studies in spiroheterocycles. Part XVII. synthesis of novel fluorine containing spiro[indole‐pyranobenzopyran] and spiro[indenopyran‐indole] derivatives
Authors: Joshi Karishna C. , Dandia Anshu , Baweja Sunita , Joshi Amitabh 
Published: March 2009

AbstractAn elegant one‐step synthesis of two novel spiro ring systems viz: spiro[3H‐indole‐3,4′‐(2′‐amino‐3′‐carbonitrile‐[4′H]‐pyrano[3,2‐c]benzopyran)]‐2,5′(1H)‐dione8 and spiro[(2‐amino‐3‐carbonitrile‐indeno[1,2‐b]pyran)‐4(5H)>3′‐[3H]indole]‐2′,5(1′H)‐diones in 80–85% yields is described. The spiro heterocycles were prepared by the reactions of fluorine containing 3‐dicyanomethylene‐2H‐indol‐2‐ones with 4‐hydroxy‐2H‐1‐benzopyran‐2‐one and 1H‐indene‐1,3(2H)‐dione respectively. The synthesized compounds have been characterized on the basis of elemental analyses, ir, pmr, 19F nmr and mass spectral data.
The x‐ray crystal and molecular structure of chloro‐α,β,γ,δ‐tetraphenylporphinatopyridinegallium(III)
Authors: Radish K. M. , Cornillon J.‐L. , Korp J. D. , Guilard R. 
Published: March 2009

AbstractCrystals of the title compound C49H33N5ClGa·1/2C5H5N·1/2C5H12 [Ga(py)(Cl)(TPP)]·1/2(py)·1/2(n‐pen) are monoclinic, P21/n, a = 13.162(2), b = 23.422(6), c, = 14.677(2) Å, β = 101.47(1)°, and Z = 4. The crystal structure refined to R = 0.056 for 2249 observed reflections. The coordination polyhedron of the gallium atom is an octahedron, and the distances between the central metal and axial ligands are Ga‐Cl = 2.328(1) and Ga‐py = 2.274(3) Å. The gallium atom is displaced slightly out of the porphyrin plane towards Cl, 0.14 Å from the 4N plane and 0.16 Å from the mean porphinato plane, with an average Ga‐N distance of 2.01 Å. Although the complex is isostructural with the Mn and Co analogs, it is the first reported structure of a monomeric hexacoordinate gallium(III) porphyrin.
Synthesis of 5‐benzoyl‐5‐phenyl‐ and 5‐phenylhydroxymethyl‐5‐phenylhydantoins as potential anticonvulsants
Authors: Crooks Peter A. , Deeks Trevor , Desimone Francesco 
Published: March 2009

AbstractA series of 5‐benzoyl‐5‐phenyl‐ and S‐phenyl‐5‐phenylhydroxymethylhydantoins have been synthesized from the reaction of urea, N‐monosubstituted ureas and sym‐N‐N‐disubstituted ureas with phenyltriketone hydrate, via a pinacol‐pinacolone‐type rearrangement mechanism. The compounds were evaluated for anti‐convulsant activity in mice.
Synthesis and spectral properties of new 6‐methoxy‐3‐(2′‐thienyl)‐1,2‐benzisoxazole and its isomeric benzoxazole
Authors: Varache‐Béranger Marline , Nuhrich Alain , Devaux Guy , Duboudin Françoise 
Published: March 2009

Abstract6‐Methoxy‐3‐(2′‐thienyl)‐1,2‐benzisoxazole has been prepared simultaneously with 6‐methoxy‐2‐(2′‐thienyl)‐1,3‐benzoxazole. The spectral data of these new compounds have been discussed. Mass spectroscopy has proved to be a valid tool in the structural characterization of these isomers and 13C nmr spectrometry confirmed their structures.
Alkyl substituted 3‐PPP derivatives. Synthesis and biological investigation
Authors: Tecle Haile , Bergmeier Stephen C. , Wise Lawrence D. , Hershenson Fred M. , Coughenour Linda L. , Heffner Thomas G. 
Published: March 2009

AbstractSynthesis of alkyl substituted derivatives of 3‐(1‐propyl)3‐piperidinyl)phenol (3‐PPP), 2–8, was carried out in an attempt to improve on the pharmacodynamic properties of 3‐PPP. No significant improvement was attained.
Etude des conditions d'accés aux 6H‐, 7H‐ et 11H‐pyrimidino‐[4,5‐a], [4,5‐b], [5,4‐a] [5,4‐b] et [5,4‐c]carbazoles. 1
Authors: Gazengel Jean‐Marie , Lancelot Jean‐Charles , Rault Sylvain , Robba Max 
Published: March 2009

AbstractLes dihydropyrimidinocarbazoles 12,15 et 18 sont accessibles par cyclisation des tétrahydrocarbazolones 11, 14 et 17 au moyen du triformamidométhane dans le formamide. Leur oxydation par le permanganate conduit aux pyrimidinocarbazoles 13, 16 et 19. Les aminocyanocarbazoles 1 et 7 constituent des intermédiaires permettant l'accés aux oxo 6H‐pyrimidinocarbazoles 2 et 8. La quinazolinylhydrazone 9, par chauffage en milieu acide permet, après cyclisation, d'accéder au tétrahydro 6H‐pyrimidinocarbazole 10. Les spectres de rmn confirment la structure des dérivés obtenus.
Synthesis and antibacterial activity of some 7‐substituted 1‐ethyl‐6‐fluoro‐1,4‐dihydro‐4‐oxoquinoline‐3‐carboxylic acids: Ethers, secondary amines and sulfides as c‐7 substituents
Authors: Ziegler Carl B. , Curran William V. , Kuck Nydia A. , Harris Sonja M. , Lin Yang‐I. 
Published: March 2009

AbstractA series of 7‐substituted 1‐ethyl‐6‐fluoro‐1,4‐dihydro‐4‐oxoquinoline‐3‐carboxylic acids were prepared from 1‐ethyl‐6,7‐difluoro‐1,4‐dihydro‐4‐oxoquinoline‐3‐carboxylic acid 8. Those derivatives reported contain acyclic and heterocyclic substituents linked to the quinolone C‐7 position via O, NH or S. The in vitro antibacterial data of some of these derivatives against 4 Gram positive and 4 Gram negative organisms are reported.
New 7‐substituted quinolone antibacterial agents. II. The synthesis of 1‐ethyl‐1,4‐dihydro‐4‐oxo‐7‐(pyrazolyl, isoxazolyl, and pyrimidinyl)‐1,8‐naphthyridine and quinolone‐3‐carboxylic acids
Authors: Domagala John M. , Peterson Phred 
Published: March 2009

AbstractSynthetic methods for the construction of certain aromatic heterocyclic side chains for the quinolone anti‐bacterials have been provided. In particular a series of 7‐(pyrazol‐3 or 4‐yl, 4‐ or 5‐isoxazolyl and 4‐ or 5‐pyrimidinyl)‐1‐ethyl‐1,4‐dihydro‐4‐oxo‐1,8‐naphthyridine and quinoline‐3‐carboxylic acids have been prepared. All of the heterocycles were prepared from masked 1,3‐dicarbonyl derivatives of nalidixic acid (9,17) or 7‐acetyl‐1‐ethyl‐1,4‐dihydro‐4‐oxo‐3‐quinoline carboxylic acids (8). These masked 1,3‐dicarbonyl derivatives were prepared by the use of t‐butoxy‐bis‐dimethylaminomethane on the activated methyls of 9,19 and 8. The pyrimidinyl analogs, substituted with a 2‐amino or a 2‐aminomethyl moiety, were the only derivatives with substantial antibacterial activity.
Photochemical conversion of o‐phenylenediamine and o‐aminophenol into heterocyclics
Authors: Crank G. , Makin M. I. H. 
Published: March 2009

Abstracto‐Phenylenediamine is photo‐oxidized to phenazine‐2,3‐diamine in ethanolic or aqueous hydrochloric acid solution. In acetic or propionic acid solutions it forms benzimidazole derivatives. o‐Aminophenol in ethanol is photo‐oxidized to 2‐amino‐3H‐phenoxazin‐3‐one and two tetracyclic solvent addition products.
Synthesis and tautomerism of ethyl 2‐(2‐benzothiazolyl)‐2‐(6‐purinyl)acetate and related compounds
Authors: Klemm L. H. , Johnstone Susan , Tran Long K. 
Published: March 2009

AbstractReaction of 6‐chloro‐9H‐(2‐tetrahydropyranyl)purine (2d) with the sodium salt of ethyl benzothiazole‐2‐ace‐tate (1) in dimethylformamide effects condensation of the two compounds (with loss of sodium chloride) to give the corresponding ethyl diarylacetate 4 (35%), present largely as an enol chelate tautomer. Isolated as a by‐product is 6‐(2‐aminophenyl‐1‐thio)‐9H‐(2‐tetrahydropyranyl)‐purine (4%), formed via opening of the thiazole ring. Removal of the tetrahydropyranyl protective group from 4 occurs by treatment with p‐toluenesulfonic acid in aqueous ethanol to produce ethyl benzothiazole‐2‐(6‐purinyl)acetate (80%), existent largely as two enol chelate isomers. Spectral data for the various products are presented. An attempt to use 6‐chloro‐9‐acetyl‐9H‐purine in place of 2d in the first reaction gives acetylation of 1 instead of condensation.
The preparation of 3,4‐dihydro‐1‐benzoxepin‐5(2H)‐ones
Authors: Freedman Jules , Stewart Kenneth T. 
Published: March 2009

AbstractSeveral methods for the preparation of 3,4‐dihydro‐1‐benzoxepin‐5(2H)‐ones are described. In addition to the desired ketones, a variety of novel by‐products have been isolated.