bluuebunny/crossref_metadata_2025_split huggingface dataset:
A facile synthesis of novel pyrazolo[5′,1′:3, 4]‐[1, 2, 4]triazino[6, 5‐f][1, 3, 4]thiadiazepines
Authors: Kurasawa Yoshihisa , Kamigaki Yumiko , Kim Ho Sik , Watanabe Chisako , Kanoh Megumi , Okiyama Mari , Takada Atsushi , Okamoto Yoshihisa 
Published: March 2009

AbstractThe reaction of the 3‐substituted 4‐aminopyrazolo[5, 1‐c][1, 2, 4]triazines 1a‐d with thiosemicarbazide hydrochloride in acetic acid gave new pyrazolo[5′,1′:3, 4][1, 2, 4]triazino[6, 5‐f][1, 3, 4]thiadiazepines 3, 4 and 6, which were converted into the 5‐oxo derivatives 5 and 7 by hydrolysis in hydrochloric acid/acetic acid.
Thermal formation of triphenodithiazinequinone and triphenodiselenazinequinone
Authors: Nishi Hisao , Minami Satoshi , Kitahara Kiyoshi 
Published: March 2009

AbstractThermal treatment of 2, 5‐bis(2‐thioanisidino)‐3, 6‐dichloro‐1, 4‐benzoquinone and its selenium derivative brought about demethylchlorination to give triphenodithiazinequinone and triphenodiselenazinequinone, respectively.
Kinetic study on the anelation of heterocycles. 2. pyrido[2,3‐b]pyrazine and pyrido[3,4‐b]pyrazine derivatives synthesized by the hinsberg reaction
Authors: Abasolo María Inés , Bianchi Daniel , Atlasovich Fabián , Gaozza Carlos , Fernández Beatriz M. 
Published: March 2009

AbstractThe regioselective synthesis of pyrido[2,3‐b]‐ and [3,4‐b]pyrazine derivatives II by the Hinsberg reaction is reported starting from 2,3 and 3,4‐diaminopyridine and excess of pyruvic acid or ethyl pyruvate as reactants. Good yields (higher than 90%) were obtained for pyrido[2,3‐b]pyrazine derivatives at room temperature using anhydrous methanol and chloroform as solvents which promote regioselective reactions to give 2‐methylpyrido[2,3‐b]pyrazin‐3(4H)‐one (3a) and 3‐methylpyrido[2,3‐b]pyrazin‐2(1H)‐one (4a) respectively. On the other hand, when the same procedure was applied to 3,4‐diaminopyridine results were not so encouraging for the formation of 2‐methylpyrido[3,4‐b]pyrazin‐3(4H)‐one (3b) and 3‐methylpyrido[3,4‐b]‐pyrazin‐2(1H)one (4b). Kinetic studies were performed in aqueous buffers (pH ‐0.89 to 11.5) and different organic solvents trying to improve yields and achieve regioselectivity. The course of the reactions was followed by uv spectrophotometry being those with ethyl pyruvate 2 to 800 times faster than with pyruvic acid. This investigation involves the kinetics and mechanism of this reaction studying its factibility when π‐deficient substrates are used and its regioselectivity according to the position of the pyridine nitrogen atom.
Synthesis of 3‐substituted‐4‐phenyl‐2‐thioxo‐1,2,3,4,5,6,7,8‐octahydrobenzo[4,5]thieno[2,3‐á]pyrimidines
Authors: Vega Salvador , Alonso Javier , Diaz Juan A. , Junquera Francisco 
Published: March 2009

AbstractThe reactions between 3‐benzoyl‐2‐isothiocyanato‐4,5,6,7‐tetrahydrobenzo[b]thiophene and hydrazine or primary amines have been studied. The products obtained were identified as derivatives of 4‐phenyl‐2‐thioxo‐2,3,5,6,7,8‐hexahydrobenzo[4,5]thieno[2,3‐d]pyrimidine. Their easy reduction with sodium borohydride provided a useful method for the synthesis of 3‐substituted‐4‐phenyl‐2‐thioxo‐1,2,3,4,5,6,7,8‐octahydrobenzo[4,5]thieno[2,3‐d]pyrimidines. Both kind of compounds were evaluated as potential analgesic, anti‐inflammatory and anti‐arthritic agents.
Synthesis and NMR (1H and 13C) Studies of azole analogs of diclofurime
Authors: Colombo Augusto , Frigola Jordi , Parés Juan , Andaluz Blas 
Published: March 2009

AbstractThe synthesis, structure elucidation and chemotherapeutic activity of novel heterocyclic analogues of the cardiotropic agent Diclofurime are reported.
Synthesis of protopine. A novel conversion of the protoberberine alkaloid stylopine to a tetrahydrodibenz[c,g]azecine derivative
Authors: Kulkarni B. K. , Dhar R. K. , De Souza N. J. 
Published: March 2009

AbstractTreatment of the methiodide of the protoberberine alkaloid, stylopine, (3) with sodium hydride in dimethyl sulfoxide afforded in 70% yield the tetrahydrodibenz[c,g]azecine derivative 4, a key intermediate in the synthesis of protopine.
Synthesis and fluorescent properties of a new photostable thiol reagent “BACM”
Authors: Chaurasia Chandra S. , Kauffman Joel M. 
Published: March 2009

AbstractThe 3‐maleimidocoumarin BACM (2d) is a new tag designed to react with thiols in biological materials to form fluorescent derivatives whose emission is in the 500 nm (green) region with good resistance to fading. The fluorescence properties of its N‐acetyl‐L‐cysteine derivative are described. BACM itself is non‐fluorescent, as is its predecessor, DACM (1a). A synthesis of BACM is reported which avoids the formation of nitrocoumarin isomers obtained in the reported synthesis of DACM. The synthesis of the related 3‐(4‐maleimidophenyl)coumarin is also described.
Synthesis of substituted dihydrobenzo[f]pyrimido[4,5‐b]‐quinolines as tetracyclic 5‐deaza nonclassical folates
Authors: Donkor Isaac O. , Gangjee Aleem , Duah Francis K. 
Published: March 2009

AbstractCyclocondensation of 2,4,6‐triaminopyrimidine (10) with chlorovinyl aldehyde7afforded the linear regioisomer 9,1 1‐diamino‐5,6‐dihydrobenzo[f]pyrimido[4,5‐c]quinoline (1) while the cyclocondensation of 2,6‐diamino‐4‐hydroxypyrimidine (11) or 6‐amino‐2,4‐dihydroxypyrimidine (12) with chlorovinyl aldehyde7was regiospecific affording the linear regioisomers 9‐amino‐11‐oxo‐5,6‐dihydrobenzo[f]pyrimido[4,5‐c]quinoline (2) and 9,11‐dioxo‐5,6‐dihydrobenzo[f]pyrimido[4,5‐c]quinoline (3) respectively. The linear structures of these compounds were established by1H nmr and13C nmr spectral data.
Synthesis and In Vivo antitumor and antiviral activities of 2′‐deoxyribofuranosyl and arabinofuranosyl nucleosides of certain purine‐6‐sulfenamides, sulfinamides and sulfonamides
Authors: Revankar Ganapathi R. , Hanna Naeem B. , Ramasamy Kandasamy , Larson Steven B. , Smee Donald F. , Finch Rick A. , Avery Thomas L. , Robins Roland K. 
Published: March 2009

Abstract2′‐Deoxyribofuranosyl and arabinofuranosyl nucleosides of certain purine‐6‐sulfenamides, sulfinamides and sulfonamides have been prepared by sequential amination and controlled oxidation of the corresponding 6‐thiopurine nucleosides, and evaluated for antiviral and antitumor activities in mice. Amination of 2′‐deoxy‐6‐thioinosine (4a) and 9‐β‐D‐arabinofuranosyl‐6‐thiopurine (4c) with chloramine solution gave the corresponding 6‐sulfenamides 5a and 5c, respectively, which on selective oxidation with 3‐chloroperoxybenzoic acid (MCPBA) gave diastereomeric 9‐(2‐deoxy‐β‐D‐erythro‐pentofuranosyl)purine‐6‐sulfinamide (6a) and 9‐β‐D‐arabinofuranosylpurine‐6‐sulfinamide (6c), respectively. However, oxidation of 5a and 5c with excess of MCPBA gave the corresponding 6‐sulfonamide derivatives 7a and 7c, respectively. Similar amination of 2′‐deoxy‐6‐thioguanosine (4b), ara‐6‐thioguanine (4d) and α‐2′‐deoxy‐6‐thioguanosine (8) gave the respective 6‐sulfenamide derivatives 5b, 5d and 9. Controlled oxidation of 5b, 5d and 9 gave (R,S)‐2‐amino‐9‐(2‐deoxy‐β‐D‐erythro‐pentofuranosyl)purine‐6‐sulfinamide (6b), (R,S)‐2‐amino‐9‐β‐D‐arabinofuranosylpurine‐6‐sulfinamide (6d) and the α‐anomer of (6b) (10), respectively. The diastereomeric mixture of (R,S)‐10 was partially resolved and the structure of S‐10 was assigned by single‐crystal X‐ray diffraction analysis. Oxidation of 5b, 5d and 9 with excess of MCPBA afforded the respective 6‐sulfonamide derivatives 7b, 7d and 11. Nucleosides 5c and 7c were significantly active against Friend leukemia virus in mice, whereas 6c was somewhat less active. Of the 20 nucleosides evaluated, 12 exhibited biologically significant anti‐L1210 activity in mice. Nucleosides 6b and 7a at 173 mg/kg/day × 1 showed a T/C of 153, whereas 7d at 800 mg/kg/day × 1 showed a T/C of 153 against L1210 leukemia. The α‐nucleoside 9 at 480 mg/kg/day × 1 gave a T/C of 172. A single treatment with 6b, 7a, 7d and 9 reduced the body burdens of viable L1210 cells by more than 99.2%. The antileukemic activity of these novel nucleosides tended to parallel solubility.
Saturated heterocycles, part 161 [1]. Synthesis of 2‐hydroxycycloalkyl‐substituted 1,3,4‐oxadiazoles, 1,3,4‐thiadiazoles and 1,2,4‐triazoles
Authors: Fülöp Ferenc , Semega éva , Dombi György , Bernáth Gábor 
Published: March 2009

AbstractA number of 2‐hydroxycycloalkyl‐substituted 1,3,4‐oxadiazole, 1,3,4‐thiadiazole and 1,2,4‐triazole derivatives were prepared by different methods from cis‐ and trans‐2‐hydroxy‐1‐cycloalkanecarbohydrazides and their isocyanate or isothiocyanate adducts. In contrast with the related ring‐closure reactions of 2‐aminobenzoylhydrazides, no condensed skeleton heterocycles were formed in this case.
Synthesis of 3,9b‐dihydro‐5H‐pyrrolo[2,1‐a]isoindoles and 3,5,6,10b‐tetrahydropyrrolo[2,1‐a]isoquinolines with 1,3‐dipolar cycloaddition reactions
Authors: Anderson Wayne K. , Kinder Frederick R. 
Published: March 2009

AbstractThe title classes of compounds have been prepared using a sequence of two ring‐forming reactions. Initial 1,3‐dipolar cycloaddition with an azomethine ylide gave N‐acylated 3‐pyrrolines which were further elaborated to the target compounds by a tandem deprotection/cyclization reaction.
Synthesis of certain 1,2,4‐triazole nucleoside derivatives
Authors: Michael Josephine , Larson Steven B. , Vaghefi Morteza M. , Robins Roland K. 
Published: March 2009

AbstractThe syntheses of 3‐amino‐4‐methyl‐1‐(β‐D‐ribofuranosyl)‐1,2,4‐triazolin‐5‐one (8a) and its 2′‐deoxy analog 8b as well as 5‐amino‐2‐methyl‐1‐(β‐D‐ribofuranosyl)‐1,2,4‐triazolin‐3‐one (12) have been accomplished. Compounds 8a and 8b were synthesized via glycosylation of 3‐bromo‐5‐nitro‐1,2,4‐triazole which was followed by replacement in three steps of the 3‐bromo function to yield 3‐nitro‐1‐(2,3,5‐tri‐O‐acetyl‐β‐D‐ribofuranosyl)‐1,2,4‐triazolin‐5‐one (4a) and its 2′‐deoxy analog 4b. Compounds 4a and 4b were methylated at N2, hydrogenated and deblocked to give 3‐amino‐4‐methyl‐1‐(β‐D‐ribofuranosyl)‐1,2,4‐triazolin‐5‐one (8a) and the 2′‐deoxy analog 8b. Compound 12 was synthesized by glycosylation of 3‐amino‐1‐methyl‐1,2,4‐triazolin‐5(2H)‐one (10). The structures of 8b and 12 were confirmed by single crystal X‐ray diffraction analysis.
Potential antitumor agents. IV. Pyrrole analogues of oncodazole
Authors: Massa Silvio , Santo Roberto Di , Artico Marino 
Published: March 2009

AbstractThe synthesis of alkyl [5‐(1H‐pyrrol‐2‐ylcarbonyl)‐1H‐benzimidazol‐2‐yl]carbamates and alkyl [5‐(1H‐pyrrol‐ 1‐ylmethyl)‐1H‐benzimidazol‐2‐yl]carbamates is described. The new pyrrole derivatives are related to oncodazole, a recent synthetic derivative showing antifungal, antitumor and anthelmintic properties.
Regio‐ and stereoselective oxetane formation via paterno‐buchi photocycloaddition
Authors: Fleming Steven A. , Jones Richard W. 
Published: March 2009

AbstractCarbonyl 2 + 2 photoaddition occurs selectively to the alkene moiety of 3‐(4‐methyl‐3‐pentenoxy)pyridine. Photolysis of alkene containing pyridines in acetophenone gives rise to an oxetane which is obtained with extremely high diastereoselectivity as shown by analysis of the major 2 + 2 photoproduct. A second photoproduct, 2,3‐dihydroxy‐2,3‐diphenylbutane, is obtained as a result of acetophenone coupling.
Preparation of potentially bioactive aza and thiaza polycyclic compounds containing a bridgehead nitrogen atom. Synthesis of pyrrolo[1,2,3‐de]‐1,4‐benzothiazine derivatives
Authors: Armenise Domenico , Trapani Giuseppe , Arrivo Vittorio , Morlacchi Flaviano 
Published: March 2009

AbstractThe synthesis of some pyrrolo[1,2,3‐de]‐1,4‐benzothiazine derivatives by using a modified Bischler type cyclization of N‐(2,2‐diethoxyethyl)‐2H‐1,4‐benzothiazines as a crucial step is described. The alternative approach based on Friedel‐Crafts alkylation of the N‐(2‐chloroethyl)‐2H‐1,4‐benzothiazines is shown to be impractical due to the low yield obtained.
Generation and dienophilic properties of 1‐benzyl‐1H‐1,2,3‐triazolo[4,5‐d]pyridazine‐4,7‐dione
Authors: Theocharis A. B. , Alexandrou N. E. , Terzis A. 
Published: March 2009

Abstract1‐Benzyl‐5,6‐dihydro‐1H,2,3‐triazolo[4,5‐d]pyridazine‐4,7‐dione (1) by oxidation with lead tetraacetate afforded the corresponding triazolopyridazine‐4,7‐dione 2 as the intermediate, which was trapped with several dienes giving the hetero‐Diels‐Alder adducts 3 in good yields. The structure of the cycloadduct 3a was determined by X‐ray analysis.
Synthesis of ellipticine and olivacine by the thermal electrocyclic reaction via pyridine 3,4‐quinodimethane intermediates
Authors: Hibino S. , Sugino E. 
Published: March 2009

AbstractA synthesis of the antitumor alkaloids ellipticine 1 and olivacine 2 is reported. The route involves a thermal electrocyclic reaction of conjugated hexatriene system 4 derived from 2‐alkenylindole derivatives 5. Heating of the 2‐alkenylindole derivative 5b at 450–460° gave ellipticine 1 (30%) and 11‐demethylellipticine 14 (43%). In a similar manner, the thermolysis of the 2‐alkenylindole 5c afforded olivacine 2 (57%).
Preparation of 8H‐Furo[3,4‐d]dibenz[b,f]azepine. A Novel Heterocyclic Ring system
Authors: Mchugh Kathleen B. , Howell William M. , Doran John J. , Cann Michael C. 
Published: March 2009

AbstractThe synthesis of 8H‐furo[3,4‐d]dibenz[b,f]azepine 8 from 5H‐dibenz[b,f]azepine 1a is described. The preparation of 8 represents the synthesis of a new heterocyclic system.
A facile and novel synthesis of 1,6‐naphthyridin‐2(1H)‐ones
Authors: Singh Baldev , Lesher George Y. 
Published: March 2009

AbstractA new and convenient procedure for the synthesis of 1,6‐naphthyridin‐2(1H)‐ones and their derivatives is described. In the first scheme 5‐acetyl‐6‐[2‐(dimethylamino)ethenyl]‐1,2‐dihydro‐2‐oxo‐3‐pyridinecarbonitrile (4) obtained by the reaction of N,N‐dimethylformamide dimethyl acetal with 5‐acetyl‐1,2‐dihydro‐6‐methyl‐2‐oxo‐3‐pyridinecarbonitrile (3) was cyclized to 1,2‐dihydro‐5‐methyl‐2‐oxo‐1,6‐naphthyridine‐3‐carbonitrile (5) by the action of ammonium acetate. Thermal decarboxylation of acid 7 obtained from the hydrolysis of nitrile 5 led to a mixture of 5‐methyl‐1,6‐naphthyridin‐2(1H)‐one (8) and its dimer 9. Hydrazide 11 obtained from nitrile 5 in two steps was converted to 3‐amino‐5‐methyl‐1,6‐naphthyridin‐2(1H)‐one (12) by the Curtius rearrangement. The amino group of 12 was readily replaced by treatment with aqueous sodium hydroxide to yield 3‐hydroxy‐5‐methyl‐1,6‐naphthyridin‐2(1H)‐one (13). In the second scheme, Michael reaction of enamines of type 20 with methyl propiolate, followed by ring closure gave 5‐acyl(aroyl)‐6‐methyl‐2(1H)‐pyridinones (21) which in turn were treated with Bredereck's reagent to produce 5‐acyl(aroyl)‐6‐[2‐(dimethylamino)ethenyl]‐2(1H)‐pyridinones (22). Treatment of 22 with ammonium acetate led to the formation of 1,6‐naphthyridin‐2(1H)‐ones 23.
Functionalized 5,6‐dihydro‐2H‐1,2,6‐thiadiazine 1,1‐dioxides. Synthesis, structure and chemistry
Authors: Lee Chai‐Ho , Kohn Harold 
Published: March 2009

AbstractTreatment of sulfamide 4a and aryl‐substituted sulfamides 4b‐e with ethyl 3,3‐diethoxypropionate (13) provided a convenient procedure for the synthesis of functionalized 5,6‐dihydro‐2H‐1,2,6‐thiadiazine 1,1‐dioxides 14. Key spectral properties of this novel class of heterocycles are reported. The generality and utility of this transformation is briefly explored.
Preparation of macrocyclic di‐ and tetraamides containing unsubstituted macroring nitrogen atoms, tertiary amine sidearms and/or piperazine subcyclic units
Authors: Bradshaw Jerald S. , Krakowiak Krzysztof E. , An Haoyun , Izatt Reed M. 
Published: March 2009

AbstractSeven new macrocyclic di‐ and tetramides have been prepared by the cyclization reaction of various polyamines or, in one case, a dimercaptan with a bis(α‐chloroamide) or diethyl malonate. Three of the resulting macrocyclic diamides were reduced with borane to form the corresponding polyaza‐crown analogs. Macrocycles prepared include two tetraaza‐12‐crown‐4, two tetraaza‐13‐crown‐4, two tetraaza‐14‐crown‐4, one dithiadiaza‐14‐crown‐4, one tetraaza‐15‐crown‐4 with a piperazine subcyclic group, one dibenzotetraaza‐24‐crown‐8 and one octaaza‐30‐crown‐8 with two piperazine subcyclic groups.
Synthesis and properties of homomologated and contracted dipyrrinone analogs of xanthobilirubic acid
Authors: Puzicha Gisbert , Shrout David P. , Lightner David A. 
Published: March 2009

AbstractDipyrrinone analogs of xanthobilirubic acid, 5‐[1,5‐didehydro‐3‐ethyl‐4‐methyl‐5‐oxo‐2H‐pyrrol‐2‐ylidene)‐methyl]‐2,4‐dimethyl‐1H‐pyrrol‐3‐propanoic acid, with alkanoic acid chain lengths varying from formic to caproic have been synthesized as their methyl esters and characterized spectroscopically. All of the dipyrrinones studied exhibit intermolecular hydrogen bonding in chloroform, as detected by 1H‐nmr, and the influence of the carboxyl group on the uv‐visible spectrum decreases with increasing chain length.
1,3‐dipolar cycloadditions of 2‐diazobutane, diazophenylmethane and 1‐diazo‐1‐phenylethane to azolopyridazines. The isolation of some primary and rearranged cycloadducts and their transformations into substituted pyrazolo[4,3‐d]azolopyridazines
Authors: Huč Branko , Furlan Borut , Stanovnik Branko , Tišsler Miha 
Published: March 2009

AbstractThe 1,3‐dipolar cycloaddition of 2‐diazobutane (2) to azolopyridazines 1 gave 9‐ethyl‐9‐methyl‐7,8‐dihydropyrazolo[4,3‐d]‐ 4 and 9‐ethyl‐9‐methyl‐9H‐pyrazolo[4,3‐d]azolopyridazines 5. With diazophenylmethane (6) 7‐benzyl‐8‐phenyl‐7H‐ 12 and 8‐benzyl‐9‐phenyl‐8H‐pyrazolo[4,3‐d]azolopyridazines 13 were obtained, while with 1‐diazo‐1‐phenylethane (14) the primary cycloadducts 15, and rearranged cycloadducts 16 and 17 were isolated in some instances and further transformed into 9‐methyl‐9‐phenyl‐9H‐pyrazolo[4,3‐d]azolopyridazines 18.
A convenient synthesis of 1,2‐diazepino[3,4‐b]‐quinoxalines via a 1,3‐dipolar cycloaddition reaction and their tautomeric structure in a solution
Authors: Kim Ho Sik , Kurasawa Yoshihisa , Yoshii Chiemi , Masuyama Minako , Takada Atsushi , Okamoto Yoshihisa 
Published: March 2009

AbstractThe reaction of the quinoxaline 4‐oxides 7a,b with 2‐chloroacrylonitrile resulted in the 1,3‐dipolar cycloaddition reaction and further alteration to give the 4‐hydroxy‐2,3‐dihydro‐1H‐1,2‐diazepino[3,4‐b]quinoxalines 8a,b and 9a,b, respectively, which were converted into the 4‐oxo‐2,3,4,6‐tetrahydro‐1H‐1,2‐diazepino[3,4‐b]‐quinoxalines 10a,b‐12a,b, respectively. The 2,3‐dihydro‐4‐hydroxy form of 9a,b and the 2,3,4,6‐tetrahydro‐4‐oxo form of 10a,b‐12a,b were assigned by means of the NOE and 13C‐nmr spectral data.
Oxidation of 3‐hydroxykynurenine. An EPR investigation
Authors: Bolognese Adele , Bonomo Raffaele P. , Chillemi Rosa , Sciuto Sebastiano 
Published: March 2009

AbstractA weak alkaline solution of 3‐hydroxykynurenine was oxidized using potassium ferricyanide. A stable epr signal was recorded, probably arising from a phenoxazine intermediate. A plausible radical mechanism for this reaction is presented.
Synthesis of phenanthro[2,3‐h]isoquinoline and phenanthro[3,2‐h]isoquinoline
Authors: Tanga Mary J. , Reist Elmer J. 
Published: March 2009

AbstractThe suspected environmental contaminants phenanthro[2,3‐h]isoquinoline 12 and phenanthro[3,2‐h]isoquinoline 11 were synthesized in four steps from a common intermediate 1,4‐phenanthroquinone 3, using a Diels‐Alder reaction.
New evidence on the formation of 3‐acylindoles by reaction of N‐phenylnitrones with α,β‐acetylenic sulfones
Authors: Broggini Gianluigi , Diliddo Dario , Zecchi Gaetano 
Published: March 2009

AbstractN‐Phenylnitrones react with α,β‐acetylenic sulfones to give ultimately 3‐acylindoles via unstable 4‐sulfonylsubstituted 2,3‐dihydroisoxazoles. In one case, a minor pathway is also operative leading to a different kind of indole derivative. Mechanistic possibilities are discussed.
Some fatty acids having O‐heterocycles in their terminal positions. III. ω‐(2‐Benzofuranyl)alkanoic acids
Authors: Yamaguchi Seiji , Yamamoto Yoshimi , Matsumoto Yoshinori , Ogiura Shigekazu , Kawase Yoshiyuki 
Published: March 2009

AbstractSome ω‐(2‐benzofuranyl)alkanoic acids 1, n = 2‐5 were synthesized by acylation of benzofuran with ω‐(ethoxycarbonyl)alkanoic acids in trifluoroacetic anhydride followed by Wolff‐Kishner reductions.
A facile synthesis of benzo[b]thiophene derivatives
Authors: Watanabe Mitsuaki , Date Mutsuhiro , Kawanishi Kenji , Akiyoshi Ryuji , Furukawa Sunao 
Published: March 2009

AbstractLithiation of S‐(2‐methylphenyl) N,N,N',N'‐tetramethylphosphorodiamidothioate with sec‐BuLi at ‐105° gave the corresponding benzylic anion which was acylated with various aromatic esters to give various deoxybenzoin derivatives in moderate to high yields. Acidic treatment of these products in refluxing formic acid gave 2‐arylbenzo[b]thiophene derivatives. 2‐Methylbenzo[b]thiophene and benzo[b]thiophen‐2(3H)‐one were also prepared using the similar procedure.
A convenient synthesis of 1,4‐dihydro‐4‐oxopyridazino[3,4‐b]quinoxalines by a ring transformation of 1,2‐diazepino[3,4‐b]quinoxalines
Authors: Kurasawa Yoshihisa , Kim Ho Sik , Kawano Tae , Katoh Ritsuko , Takada Atsushi , Okamoto Yoshihisa 
Published: March 2009

AbstractThe reaction of the 1,2‐diazepino[3,4‐b]quinoxalines 2a,b or 3a,b with N‐bromosuccinimide/water resulted in ring transformation to give the 1,4‐dihydro‐4‐oxopyridazino[3,4‐b]quinoxalines 4a,b, respectively.
The synthesis of novel polycyclic heterocyclic ring systems via photocyclization. 3. 12‐Methylbenzo[h][1]benzothieno[2,3‐c][1,6]naphthyridine
Authors: Musmar M. J. , Castle Raymond N. 
Published: March 2009

AbstractThe synthesis of the 12‐methyl derivative of a novel heterocyclic ring system, namely benzo[h][1]benzothieno[2,3‐c][1,6]naphthyridine (8) was prepared by photocyclization of 3‐chloro‐N‐(2′‐methyl‐4′‐quinolyl)benzo‐[6]thiophene‐2‐carboxamide (5) to 12‐methylbenzo[h][1]benzothieno[2,3‐c][1,6]naphthyridin‐6(5H)‐one (6). Chlorination of 6 afforded 6‐chloro‐12‐methylbenzo[h][1]benzothieno[2,3‐c][1,6]naphthyridine (7) which upon dechlorination provided the novel title compound 8.
Novel pyrimidine and pyrimido[1,2‐a]pyrimidine derivatives. By‐products of a guanidine based thymine synthesis
Authors: Stoss Peter , Kaes Elmar , Eibel Guenter , Thewalt Ulf 
Published: March 2009

AbstractThe isolation, structural elucidation, directed preparation and some derivatives of three previously unknown heterocycles is reported. Arising from a guanidine based thymine synthesis, these novel compounds exhibit substituted and fused pyrimidine structures repectively.
Synthesis and biological evaluation of 5‐(1‐alkoxy‐2‐haloethyl)‐2′‐deoxyuridines and related uracil analogues
Authors: Kumar Rakesh , Wiebe Leonard I. , Knaus E. E. , Tempest Mark L. 
Published: March 2009

AbstractA new class of 5‐[1‐alkoxy‐2‐iodo(or 2,2‐diiodo)ethyl] derivatives of 2′‐deoxyuridine and uracil were synthesized by a regiospecific reaction of the C‐5 vinyl substituent with iodine monochloride and an alcohol. These compounds were either weak or inactive antiviral and inactive cytotoxic agents.
The preparation of some tetradecyl‐substituted benzocarbazoles and benzacridines
Authors: Katritzky Alan R. , Wang Zuoquan , Savage G. Paul 
Published: March 2009

AbstractThe preparations are described of 10‐dodecyl‐ and 10‐tetradecylbenzo[a]acridines, 9‐tetradecylbenzo[c]acridine, and some 8‐tetradecylbenzo[a]carbazoles and 10‐tetradecylbenzo[c]carbazoles.
Asymmetric reduction of 7,8‐difluoro‐3‐methyl‐2H‐1,4‐benzoxazine. Synthesis of a key intermediate of (S)‐(‐)‐ofloxacin (DR‐3355)
Authors: Atarashi Shohgo , Tsurumi Hideaki , Fujiwara Toshihiro , Hayakawa Isao 
Published: March 2009

AbstractAn efficient, highly enantioselective synthesis of (S)‐(‐)‐7,8‐difluoro‐2,3‐dihydro‐3‐methyl‐4H‐1,4‐benzoxazine, a key intermediate of (S)‐(‐)‐ofloxacin, using various chiral sodium triacyloxyborohydrides as reducing agents is reported.