bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new route to 2‐amino‐ or 2‐hydroxy‐3‐pyridinecarboxylic acid derivatives
Authors: Ito Kunio , Yokokura Seiichi , Miyajima Shingo 
Published: March 2009

AbstractSchiff's bases derived from ketones and t‐butylamine (1) reacted with methyl methoxymethylenemalonate to give 2‐hydroxy‐3‐pyridinecarboxylates. Similarly, treatment of 1 with ethoxymethylenemalononitrile gave 2‐amino‐3‐pyridinecarbonitriles. Compounds 1 on reaction with ethyl 2‐cyano‐3‐ethoxypropenoate afforded 2‐amino‐3‐pyridinecarboxylates.
Some derivatives of benz[f]azepine. Part III
Authors: James Robert A. , Kohn Charlotte A. , Rees Alun H. , Verschuren Rex E. 
Published: March 2009

AbstractWe report the synthesis by two routes, of hitherto unknown 3, 4‐epoxy‐2, 3, 4, 5‐tetrahydrobenz[f]azepine‐2, 5‐dione and hence a new route to 2, 3, 4, 5‐tetrahydrobenz[f]azepine‐2, 4, 5‐triones which are precursors of 2‐quin‐olonecarboxylic acids.
Preferable tautomer of dihydropyrazolo[5, 1‐c][1, 2, 4]triazines in solution
Authors: Kurasawa Yoshihisa , Kamigaki Yumiko , Kim Ho Sik , Yonekura Keiko , Takada Atsushi , Okamoto Yoshihisa 
Published: March 2009

AbstractDihydropyrazolo[5, 1‐c][1, 2, 4]triazines 6, 7 and 8 were found to predominate as the 4, 6‐dihydro tautomeric form in solution by the measurement of ID NOE different spectra.
Synthesis and derivatization of 4‐arylsulfonylthiophene‐ and furan‐2‐sulfonamides
Authors: Hartman George D. , Halczenko Wasyl 
Published: March 2009

AbstractNovel 4‐arylsulfonylthiophene‐ and furan‐2‐sulfonamides are prepared from the 3‐arylsulfonyl heterocycle via chlorosulfonation with chlorosulfonic acid/phosphorus pentachloride. Free radical bromination affords bromomethyl analogues that are precursors to amine derivatives of the parent thiophenesulfonamides. Instability of the furansulfonyl chlorides to free radical bromination necessitated a sequence employing bromomethyl group generation prior to chlorosulfonation. Demethylation of methoxyl substituted sulfonamides afforded phenols that underwent efficient mono‐ and bis‐alkylation with Mannich reagents.
Studies on structurally simple α,β‐butenolides. VIII. 5‐Haloalkyl‐ and 3‐bromo‐5‐hydroxyalkyl‐2(5H)‐furanones
Authors: Font J. , Sánchez‐Ferrando F. , Segura C. , Piniella Joan F. , Jeffrey George A. , Ruble John R. 
Published: March 2009

AbstractBromine and NBS react with sorbic acid to yield bromohydrin 5 and bromolactones 4, respectively. The erythro and threo isomers 4a,b were separated and the crystal structure of the former was determined. Bromolactone 7, as a single erythro stereoisomer, was prepared by photolactonization of 5.
Reaction of N‐nitroaryl‐1,2,3,4‐tetrahydroisoquinoline derivatives with oxygen
Authors: Shawcross A. P. , Stanforth S. P. 
Published: March 2009

AbstractHeating N‐4′‐methyl‐2′‐nitrophenyl‐1,2,3,4‐tetrahydroisoquinoline (1) in the presence of oxygen gave both products derived from cleavage of the C8aCl bond and oxidation at the 1‐position. Under similar conditions N‐4′‐nitrophenyl‐1,2,3,4‐tetrahydroisoquinoline (4) gave only the oxidation product.
The synthesis and transformations of 2‐ethoxycarbonyl‐3‐isothiocyanatopyridine. Pyrido[3,2‐d]pyrimidines and some azolopyrido[3,2‐d]pyrimidines
Authors: Urleb UroŠ , Stanovnik Branko , Tišler Miha 
Published: March 2009

Abstract2‐Ethoxycarbonyl‐3‐isothiocyanatopyridine (2), prepared from 3‐amino‐2‐ethoxycarbonylpyridine (1) by the thiophosgene method, was converted with nucleophiles into pyrido[3,2‐d]pyrimidine derivatives 6–11 and 25–30 either directly, or through thiourethane 3. Tricyclic systems 18 and 19 were obtained from 3, and tricyclic systems 12–17 from pyrido[3,2‐d]pyrimidine derivative 11. Pyrrole reacted with 2 at C2 to give 20, and by further cyclization 21 and 22.
Synthesis of 4‐[3‐(1H)‐indolyl]‐2‐[N‐guanidinomethyl]thiazole dihydrochloride
Authors: Zawistoski Michael P. 
Published: March 2009

AbstractThe title compound 3b was synthesized in three steps from acetaminothioacetamide (4b) in 15% overall yield. This represents the first synthesis of a 2‐guanidinomethylthiazole, which is a homolog of an important pharmacophore, 2‐guanidinothiazole.
Polarized ethylenes. IV. Synthesis of polarized ethylenes using thioamides and methyl dithiocarboxylates and their application to syntheses of pyrazoles, pyrimidines, pyrazolo[3,4‐d]pyrimidines, and 5‐aza[2.2.3]cyclazines
Authors: Tominaga Yoshinori , Matsuoka Yoshiki , Oniyama Yukio , Uchimura Yoshimitsu , Komiya Hirofumi , Hirayama Michiyo , Kohra Shinya , Hosomi Akira 
Published: March 2009

AbstractPolarized ethylenes having both electron‐donating (an amino or a methylthio group) and electron‐accepting (cyano, carbamoyl, methyl ester) groups on the adjacent two olefinic carbon atoms were prepared by the condensation of S‐alkylthioamidinium salts or methyl dithiocarboxylates with the corresponding active methylene compounds in good yields. These polarized ethylenes were alternatively synthesized by the reaction of thioamides or methyl dithiocarboxylates with tetracyanoethylene oxide in good yields. Reactions of these polarized ethylenes with hydrazine or guanidine derivatives occurred smoothly to give the corresponding pyrazole and pyrimidine derivatives in good yields. The synthesis of 5‐aza[2.2.3]cyclazine derivatives using polarized ethylenes is also described.
Synthesis of cns potentially active bicyclic and tricyclic derivatives of pyrazolo[1,5‐a][1,3]diazepines
Authors: Costanzo Annarella , Bruni Fabrizio , Auzzi Gabriella , Selleri Silvia , Vettori Lorenzo Pecori 
Published: March 2009

AbstractReaction of 5‐ethylamino‐3‐phenylpyrazole with dicarboxylic acid anhydrides in tetrahydrofuran in the presence of 1,3‐dicyclohexylcarbodiimide, afforded bicyclic and tricyclic derivatives of pyrazolo[1,5‐a][1,3]‐diazepines. The tricyclic derivatives constitute a new class of compounds. Characterisation of these products was effected with ir, pmr, and 13C nmr spectral data.
A convenient synthesis of 3‐aryl‐4H‐ Benzopyrano[3,4‐d]isoxazol‐4‐ones
Authors: Litinas Konstantinos E. , Nicolaides Demetrios N. , Varella Evangelia A. 
Published: March 2009

AbstractRegioselective 1,3‐dipolar cycloaddition of nitrile oxides 5a‐c to ethyl o‐hydroxycinnamate (3) gave the corresponding ethyl trans‐3‐aryl‐4,5‐dihydro‐5‐(2‐hydroxyphenyl)‐4‐isoxazolecarboxylates 6a‐c. Their structure was confirmed by reductive cleavage to 1 and compounds 9a‐c. Compounds 6a‐c afforded upon heating in the presence of pyridine the 3‐aryl‐4H‐[1]benzopyrano[3,4‐d]isoxazol‐4‐ones 11a‐c. Compound 10c was also isolated from 6c and transformed thermally into 11c.
Cyclic guanidines: Synthesis of 4,6,7,8‐tetrahydro‐1H‐imidazo[1,2‐a]pyrazolo[3,4‐d]pyrimidin‐7‐ones and 1,4,6,7,8,9‐hexahydropyrazolo[3′,4′:4,5]pyrimido[2,1‐c] [1,2,4]triazin‐7‐ones
Authors: Ferroni R. , Simoni D. , Orlandini P. , Guarneri M. , Bertolasi V. , Ferretti V. 
Published: March 2009

AbstractThe synthesis of potential platelet aggregation inhibitors 4,6,7,8‐tetrahydroimidazo[1,2‐a]pyrazolo[3,4‐d]‐pyrimidin‐7‐ones and 1,4,6,7,8,9‐hexahydropyrazolo[3′,4′:4,5]pyrimido[2,1‐c] [1,2,4]triazin‐7‐ones derivatives is described starting from 4,6‐dichloropyrazolo[3,4‐d]pyrimidines.
A New and simple synthesis of 2‐aryl‐4,9‐dihydrocyclohepta[b]pyran‐4,9‐diones
Authors: Wang Dao‐Lin , Jin Zhong‐Tian , Imafuku Kimiaki 
Published: March 2009

Abstract3‐Acetyltropolone (1) reacted with 2‐methoxybenzaldehyde (2a) in the presence of ethyl orthoformate and perchloric acid to afford 2‐(2‐methoxyphenyl)‐4,9‐dihydrocyclohepta[b]pyran‐4,9‐dione (3a). The reactions with 3,4‐dimethoxybenzaldehyde (2b), vanillin (2c), and piperonal (2d) gave respectively the corresponding products 3b‐d. The reaction with benzaldehyde (2e) gave uncyclized 3‐cinnamoyltropolone (4).
Preparation of large macrocyclic tetra‐amines consisting of a methylene backbone and a cyclophane type skeleton
Authors: Uoto Kouichi , Tomohiro Takenori , Okuno Hiroaki (Yohmei) 
Published: March 2009

AbstractEfficient synthetic routes to 1,10,19,28‐tetraazacyclohexatriacontane, a 36‐membered ring compound with a methylene backbone, and bis(N,N‐octamethylene‐4,4′‐diaminodiphenylmethane), a 38‐membered tetra‐amine with a cyclophane skeleton, have been developed via reduction of tetralactam and via a double condensation reaction, respectively. Overall yields are 51% with 5 steps for the former, and 46% with 6 steps for the latter, while the corresponding 2 + 2 cyclization gave the cyclic compounds in poor yields, 9% and 4%, respectively, for the 36‐membered tetra‐aza ring and for the 38‐membered cyclophane derivative.
Reaction of isocyanates with 2‐phenyliminotetrahydro‐1,3‐thiazines and oxazines
Authors: Nabeya Aiko , Endo Tadatoshi , Saito Jun , Mitsuishi Takatoshi , Inahara Masashi 
Published: March 2009

AbstractIt has been found that the reaction of isocyanates with 2‐phenyliminotetrahydro‐1,3‐thiazines and oxazines 3–8 occurs at the ring nitrogen to give the endo carbamoylated compound first, and then the carbamoyl group migrates to the exo nitrogen with differing rates depending upon the structure of the thiazines or the oxazines. Though the carbamoylated thiazines (both endo and exo) were found to exist in equilibrium with the isocyanate and the thiazine in solution, crossover experiments showed that the rearrangement proceeded by an intramolecular mechanism.
Synthesis of novel 1H‐imidazo[5,1‐B][3]benzazepine‐1,3(2H)‐dione and pyrimido[6,1‐B][3]benzazepine‐1,3,4(2H)‐trione
Authors: Gallaschun Randall J. , Schnur Rodney C. 
Published: March 2009

AbstractTwo novel tricyclic ring systems derived from 3‐benzazepines were synthesized; the first, a 6,7,5‐ring, 1H‐imidazo[5,1‐b][3]benzazepine‐1,3(2H)‐dione was obtained using an unusual Stiles reaction while the second, an analogous 6,7,6‐ring, pyrimido[6,1‐b][3]benzazepine‐1,3,4(2H)‐trione was prepared with base and oxalyl chloride.
Studies on the chemistry of O,N‐ and S,N‐containing heterocycles. 12 [1]. Investigations on the synthesis of tricyclic 1,5‐benzoxazepines
Authors: Bartsch Herbert , Erker Thomas 
Published: March 2009

AbstractThe reaction of methylthiolactim 1 with weak basic N‐nucleophiles led to the substituted benzoxazepines 2,3 and 6a‐d, respectively. Compound 4 was obtained by condensation of 3 with carbonyldiimidazole, whereas 6a‐d were transformed thermically into the triazolobenzoxazepines 7a‐d. Treatment of 6b with thionyl chloride afforded 8. Compound 9 directly was obtained from 1 with anthranilic acid.
Synthesis of pyridazino[3,4‐b]quinoxalines and pyrazolo[3,4‐b]‐quinoxaline by 1,3‐dipolar cycloaddition reaction
Authors: Kim Ho Sik , Kurasawa Yoshihisa , Yoshii Chiemi , Masuyama Minako , Takada Atsushi , Okamoto Yoshihisa 
Published: March 2009

AbstractThe pyridazino[3,4‐b]quinoxalines 6a,b and pyrazolo[3,4‐b]quinoxaline hydrochloride 9 were synthesized by the 1,3‐dipolar cycloaddition reaction of 6‐chloro‐2‐(1‐methylhydrazino)quinoxaline 4‐oxide 5 with dimethyl or diethyl acetylenedicarboxylate and 2‐chloroacrylonitrile, respectively. The reaction mechanisms were postulated for the formation of 6a,b and 9.
Synthesis of pyrrolo[1,2‐a]quinoxalines by 1,3‐dipolar cycloaddition reaction. An additional reaction mechanism via an aziridine intermediate
Authors: Kim Ho Sik , Kurasawa Yoshihisa , Yoshii Chiemi , Masuyama Minako , Takada Atsushi , Okamoto Yoshihisa 
Published: March 2009

AbstractThe reaction of the 2‐substituted 6‐chloroquinoxaline 4‐oxides 1a or 1b with 2‐fold molar amount of methyl propiolate resulted in the 1,3‐dipolar cycloaddition reaction to give 8‐chloro‐1,3‐bismethoxycarbonyl‐4‐(piperidin‐1‐yl)pyrrolo[1,2‐a]quinoxaline 4a or 8‐chloro‐1,3‐bismethoxycarbonyl‐4‐(morpholin‐4‐yl)pyrrolo‐[1,2‐a]quinoxaline 4b, respectively. Compound 4a or 4b was transformed into 8‐chloro‐3‐methoxycarbonyl‐4‐(piperidin‐1‐yl)pyrrolo[1,2‐a]quinoxaline 5a or 8‐chloro‐3‐methoxycarbonyl‐4‐(morpholin‐4‐yl)pyrrolo[1,2‐a]‐quinoxaline 5b, respectively. The structure of 4a,b was confirmed by the NOE measurement among the C1‐H, C2‐H and C9‐H proton signals of 5a,b. An additional reaction mechanism was proposed for the ring transformation of isoxazolo[2,3‐a]quinoxalines into pyrrolo[1,2‐a]quinoxalines.
Synthesis of isoxazolo[2,3‐a]quinoxalines and pyrrolo[1,2‐a]quinoxalines by 1,3‐dipolar cycloaddition reaction
Authors: Kim Ho Sik , Kurasawa Yoshihisa , Yoshii Chiemi , Masuyama Minako , Takada Atsushi , Okamoto Yoshihisa 
Published: March 2009

AbstractThe isoxazolo[2,3‐a]quinoxalines 11a,b and pyrrolo[1,2‐a]quinoxalines 12a,b were selectively synthesized from the 2‐substituted 6‐chloroquinoxaline 4‐oxides 10a,b. The pyrrolo[1,2‐a]quinoxalines 12a,b were clarified to be produced by the ring transformation of the isoxazolo[2,3‐a]quinoxalines 11a,b. The pyrrolo[1,2‐a]quinoxalines 14a,b were obtained from both 2,6‐dichloroquinoxaline 4‐oxide 9 and compounds 12a,b.
Transaminations of enaminones:A Synthesis of tricyclic, N‐aryl, 1,2,3‐triazole‐fused pyridones
Authors: Chan Tze‐Ming , Friary R. , Jones H. , Schwerdt J. H. , Seidl V. , Watnick A. S. , Williams S. M. 
Published: March 2009

Abstract1‐Phenylmethyl‐ and 1‐(4‐methoxyphenylmethyl)‐5‐chloro‐1,2,3‐triazole‐4‐carbonyl chlorides acylated the pyrrolidine enamines of cyclopentanone and cyclohexanone, and the resulting enaminones underwent transaminations with aryl amines under acidic conditions. The products then cyclized under basic conditions to linearly fused, tricyclic 3‐phenylmethyl‐ and 3‐(4‐methoxyphenylmethyl)‐4‐aryl‐8‐oxo‐4,5,6,7‐tetrahydrocyclopenta[6]‐1,2,3‐triazolo[4,5‐e]pyridines, and to 5,6,7,8‐tetrahydro‐4‐aryl‐3H‐1,2,3‐triazolo[4,5‐b]quinolin‐9(4H)‐ones. Similar transaminations afforded the related 8‐phenyl‐ and 8‐(3‐chlorophenyl)‐1,5,7,8‐tetrahydro‐1‐(phenylmethyl)‐4H‐thieno[3,4‐e]‐1,2,3‐triazolo[4,5‐b]pyridin‐4‐ones. Phase‐transfer and catalytic hydrogenolyses of some of these intermediates furnished 4‐aryl‐8‐oxo‐4,5,6,7‐tetrahydrocyclopenta[b]‐1,2,3‐triazolo[4,5‐e]pyridines and 4‐aryl‐5,6,7,8‐tetrahydro‐3H,2,3‐triazolo[4,5‐b]quinoline‐9‐(4H)‐ones.The 3‐(4‐methoxyphenylmethyl)‐4‐aryl intermediates were sterically crowded. Two protons from the methoxyphenylmethylphenylmethylgroups were dramatically shielded because of anisotropic effects exerted by the 4‐aryl substituents.
Preparation, characterization and reactions of novel vicinal dibenzotriazol‐1‐yl derivatives of benzotriazole and glyoxal
Authors: Katritzky Alan R. , Fan Wei‐Qiang 
Published: March 2009

AbstractA variety of novel 1,2‐disubstituted‐1,2‐di(benzotriazol‐1‐yl)ethane and 1,2‐di(benzotriazol‐1‐yl)ethylene derivatives were prepared from the adduct of benzotriazole and glyoxal.
Preparation of a variety of macrocyclic Di‐ and tetraamides and their peraza‐crown analogs using the crab‐like cyclization reaction
Authors: Krakowiak Krzysztof E. , Bradshaw Jerald S. , Izatt Reed M. 
Published: March 2009

AbstractTwelve new macrocyclic di‐ and tetraamides have been synthesized from the reaction of a bis(α‐chloroamide) with a primary amine or with a diamine. Some of these cyclic di‐ and tetraamides contained pendant aminoalkyl groups attached on one or more ring nitrogen atoms. Two macrocyclic dithiadiamides were prepared from the reaction of a bis(α‐chloroamide) and a dimercaptan. In every case, 12‐, 14‐ and 15‐membered cyclic di‐ and tetraamides were isolated in good yields. The 9‐, 17‐ and 18‐membered macrocycles were prepared in lower yields. Four of the amide‐containing macrocycles were reduced by diborane to the perazacrown compounds.
Fused s‐triazino heterocycles. XVI. 13H‐1,3,7,8,12a, 13c‐hexaazabenzo[de]naphthacene and 1,3,7,8,11b, 12,14,14d‐octaazadibenzo[de,hi]naphthacene, two new ring systems
Authors: Shaw John T. , Egler Mallory F. , Peciulis Victoria S. , Pustover Regina , Ruth William G. 
Published: March 2009

AbstractThe reaction of 7,9‐dibromo‐5‐tribromomethyl‐2‐t‐butyl‐4‐cyano‐1,3,6,9b‐tetraazaphenalene (1a) with 2‐amino‐5‐picoline is shown to give 4,6‐dibromo‐2‐t‐butyl‐13‐imino‐11‐methyl‐13H‐1,3,7,8,12a,13c‐hexaazabenzo[de]naphthacene (3) and the isomeric 7,9‐dibromo‐2‐t‐butyl‐4‐cyano‐5N‐(5‐methyl‐2‐pyridyl)amino‐1,3,‐6,9b‐tetraazaphenalene (2a). A related annulation reaction of 7,9‐dibromo‐2‐t‐butyl‐5‐chloro‐4‐cyano‐1,3,6,9b‐tetraazaphenalene (1g) with 2‐amino‐6‐trimethylacetamidopyridine leads in two steps to 4,6‐dibromo‐2,13‐di‐t‐butyl‐1,3,7,8,11b,12,14,14d‐octaazadibenzo[de,hi]naphthacene (4a). The preparation of 1g, 5‐azido‐7,9‐dibromo‐2‐t‐butyl‐4‐cyano‐1,3,6,9b‐tetraazaphenalene (1c) and the reaction of the latter with pyrrolidine leading to 7,9‐dibromo‐2‐t‐butyl‐4‐cyano‐5‐(1‐pyrrolidino)‐1,3,6,9b‐tetraazaphenalene (1e) are also reported. Attempted displacement of the azido‐group on 1c by 2,6‐diaminopyridine affords surprisingly 5‐amino‐7,9‐dibromo‐2‐t‐butyl‐4‐cyano‐1,3,6,9b‐tetraazaphenalene (1d).
Synthèse et étude physicochimique des 1,2,4‐triazolo[4,3‐a]‐pyridines et des 1,2,4‐triazolo[2,3‐a]pyridines
Authors: Bouteau Brigitte , Lancelot Jean‐Charles , Robba Max 
Published: March 2009

AbstractLes 8‐nitro‐1,2,4‐triazolo[4,3‐a] et [2,3‐a]pyridines 7–8 sont accessibles par cyclisation de la 2‐hydrazino‐8‐nitropyridine 3a dans l'acide formique. Leur réduction par l'hydrogène sous pression en présence de charbon palladié conduit suivant les conditions aux triazolopyridines 9–13 où à la triazolopyridine 10 par action du chlorure stanneux en milieu acide. Les spectres de rmn confirment la structure des dérivés obtenus.
Synthesis and spectral data of 4,5‐bis[5‐aryl‐1,3,4‐oxadiazol‐2‐yl]‐1‐benzyl‐1,2,3‐triazoles
Authors: Theocharis A. B. , Alexandrou N. E. 
Published: March 2009

AbstractThe synthesis of the title compounds 3 upon cyclodehydration with thionyl chloride of the corresponding bis‐aroylhydrazides 2 is described and their spectral properties are examined.
Assembled systems [picoline]‐[X‐azolopyridine]: Bases, salts and polymethine dyes
Authors: Savarino Piero , Viscardi Guido , Barni Ermanno , Carpignano Rosarina 
Published: March 2009

AbstractA series of assembled heterocyclic bases containing picolines and X‐azolopyridines was synthesized, thus widening the outline of available compounds for a comparison of their chemical, physical and spectroscopic properties. In particular, the competition of three different sites toward quaternizing agents has been explored and individual behaviours have been clarified by 1H nmr spectroscopy. Styryl dyes have been prepared and characterized. The effect of cationic and anionic surfactants on deaggregating one unsymmetrical cyanine has been successfully tested.
Oxygen‐17 and carbon‐13 nuclear magnetic resonance spectra of thiophene‐ and pyrrole‐2‐carboxaldehyde condensation products prepared from ephedrine derivatives
Authors: Eggleton Gordon L. , Cooper Bill A. , Sturch Chris L. , Trent Jonathan C. , Mulekar Satish V. 
Published: March 2009

AbstractNatural abundance 17O nmr (acquired in acetonitrile at 70°) and 13C nmr (acquired in deuteriochloroform at 37°) spectroscopic data for four oxazolidines and related imino alcohols are reported: relationships of chemical shifts and 17O line widths at half‐heights to structures are discussed.
Electron impact induced synthesis of benzo[2,1‐b:3,4‐b′]dithiophene
Authors: Sturaro Alberto , Traldi Pietro , Audisio Guido , Destri Silvia , Catellani Marinella 
Published: March 2009

AbstractThe photochemical behaviour of cis and trans 1,2‐bis(2‐bromo‐3‐thienyl)ethene has been separately studied with respect to cyclization to benzo[2,1‐b:3,4‐b′]dithiophene (BDT). The gc/ms analysis of the mother liquors of the two isomers photoreaction shows the opposite direction of isomerization followed by production of intractable materials resulting by the radical breaking of one of the two C‐Br bonds on the thiophene moiety. On the contrary, in EI mass spectrometry both the isomers give rise to fragment ions at m/z 190 studied and compared to BDT with the aid of mass analysed ion kinetic energy spectrometry and collisional spectroscopy.
Synthesis, alkylation and ring opening of two differently fused pyridoquinazolones
Authors: Timári Géza , Hajós György , Messmer András 
Published: March 2009

AbstractAlkylation of two differently (linearly and angularly) fused pyridoquinazolones 7 and 10 have been investigated. The linear 7 afforded exclusively N‐alkyl derivatives 4, whereas the angular 10 gave both N‐ and O‐alkyl products 5 and 11, respectively depending on the type of the reagent used. Reaction of the new alkylated salts 4, 5, and 11 with nucleophiles was found strongly dependent on the fusion type of the substrates: the reaction of the linear salt 4 led to opening of the pyrimidine moiety, and the angularly fused salts 5, 11 reacted at the pyridine site to give quinazolyldieneamines 17, 19. Regioselectivities of the observed conversions were interpreted on FMO basis.
The synthesis of substituted 2,3‐dihydrothieno[2,3‐b]‐thiophenes via intramolecular michael addition
Authors: Williams Theresa M. , Hudcosky Ronald J. , Hunt Cecilia A. , Shepard Kenneth L. 
Published: March 2009

AbstractThe first regiospecific synthesis of the 2,3‐dihydrothieno[2,3‐b]thiophene ring system was achieved using an intramolecular Michael addition in the key cyclization step. This strategy represents a novel and potentially general method for dihydrothiophene and dihydrothiophene S,S‐dioxide annellation.
Synthesis of 3‐substituted 2‐hydroxybenz[f]indolequinones and benz[f]isatinquinone ‐ A new π‐acceptor system
Authors: Shakhnovich A. I. 
Published: March 2009

AbstractStarting from 2,3‐dichloro‐1,4‐naphthaquinone a series of 2‐hydroxy‐1‐methylbenz[f]indolequinones bearing benzyl‐, amino‐ and hydroxy substituents in position 3, and benz[f]isatinquinone have been synthesised and their reactions have been studied.
Reactions with hydrazidoyl halides. IV. Synthesis of thiazolo[3,2‐a]benzimidazoles, imidazo[2,1‐6]thiazoles and pyrazolo[4,3‐b]thiazines
Authors: Abdelhamid Abdou O. , Attaby Fawzy A. 
Published: March 2009

AbstractHydrazidoyl halides were condensed with 2‐mercaptobenzimidazole yielding 4a‐c and 7a,b which were cyclized to the corresponding 2‐arylhydrazonothiazolo[3,2‐a]benzimidazol‐3‐ones 5a,b and 3‐substituted 2‐arylazo thiazolo[3,2‐a]benzimidazoles 8a,b respectively. Imidazo[2,1‐b]thiazoles were obtained by the reaction of hydrazidoyl halides with 2‐mercapto‐4,5‐dihydroimidazole. Also, hydrazidoyl halides 6a,b were reacted with 3‐amino‐4‐mercapto‐5‐phenylpyrazole to give pyrazolo[4,3‐b]thiazines 15a,b. The structures of the products were assigned on the basis of their elemental analysis and spectral data.
Acid‐catalyzed reactions of 1‐ and 3‐(α‐hydroxybenzyl)indolizines
Authors: Miki Yasuyoshi , Hiroishi Yuji , Hachiken Hiroko , Takemura Shoji 
Published: March 2009

AbstractTreatment of 1‐(α‐hydroxybenzyl)‐ and 3‐(α‐hydroxybenzyl)indolizines with trifluoroacetic acid in dichloromethane gave phenylbis(α‐indolizinyl)methanes, bis[α‐(indolizinyl)benzyl] ethers and indolizines, depending upon the presence or absence of the substituent at the 2‐ or 5‐position and the reaction conditions used.
Synthesis and identification of new thieno[3,2‐b] benzothiophenes
Authors: Jackson Johnny L. 
Published: March 2009

AbstractThe reaction of 2‐lithiobenzo[b]thiophenes with ketones produced 2‐hydroxyalkylbenzo[b]thiophenes which were cyclized in thionyl chloride to give novel thieno[3,2‐b][1]benzothiophenes. Oxidation with peroxyacetic acid gave the S,S‐dioxides whose regiochemistry was identified from 1H nmr model studies using substituted benzo[b]thiophenes and their corresponding‐1,1‐dioxides [1].