bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and tautomeric behavior of 3‐(pyrazolylhydrazonomethyl)‐2‐oxo‐1, 2‐dihydroquinoxalines. Specification of hydrazone imine and diazenyl enamine forms
Authors: Kurasawa Yoshihisa , Kim Ho Sik , Yonekura Keiko , Takada Atsushi , Okamoto Yoshihisa
Published: March 2009

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

The 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

Thermal 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

The 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

The 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

The 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

Treatment 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

The 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

Cyclocondensation 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

2′‐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

A 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

The 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

The 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

The 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

Carbonyl 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

The 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

1‐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

A 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

The 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

A 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

Treatment 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

Seven 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

Dipyrrinone 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

The 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

The 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

A 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

The 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

N‐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

Some 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

Lithiation 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

The 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

The 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

The 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

A 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

The 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

An 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.
Heterocyclic variants of the 1,5‐benzodiazepine system. VI. Derivatives of 2‐methylthio‐4‐(p‐r‐phenyl)‐3H‐1,5‐benzodiazepines
Authors: Cortés Eduardo , Martínez Roberto , Ugalde Martha , Maldonado Napoleón
Published: March 2009

Ethyl 3‐[3H‐1,5‐benzodiazepin‐2‐yl]carbazates II were prepared in moderate yields from the title compounds and ethyl carbazate. The compounds II were easily transformed into 1H‐s‐triazolo[4,3‐a][1,5]benzodiazepin‐1‐ones III via a one‐step procedure. Reaction of triazolo‐1,5‐benzodiazepinones III with sodium hydride in methyl iodide gave a mixture of products from which were isolated two compounds IV and V. The structure of all products was confirmed by ir, 1H nmr and mass spectrometry.
Synthesis of new benzofuro and indolobenzoazepin‐6‐ones
Authors: Viti Giovanni , Giannotti Danilo , Nannicini Rossano , Ricci Renzo , Pestellini Vittorio
Published: March 2009

Three new tetracyclic structures, containing the azepine ring, were synthesized: 11,12‐dihydro‐6H‐benzofuro[3,2‐c][2]benzoazepine‐6,11‐dione, 5,6,11,12‐tetrahydroindolo[3,2‐c][2]benzoazepine‐6,11‐dione and 11,12‐dihydro‐6H‐benzofuro[3,2‐c][2]benzoazepin‐6‐one.
Synthesis and characterization of alkyl‐, alkenyl‐, acyl‐ and nitrogen‐substituted derivatives of the potent phototoxin α‐terthiophene
Authors: Soucy‐Breau Chantal , Eachern Anita Mac , Leitch Leonard C. , Arnason Thor , Morand Peter
Published: March 2009

Some alkyl‐, alkenyl‐, acyl‐ and nitrogen‐ derivatives of α‐terthienyl 1 have been synthesized in an effort to expand the potential insecticidal activity profile of this compound. The introduction of substituents was carried out directly on the α‐terthienyl molecule. Three compounds were isolated in the nitration reaction and the compounds have been identified as 5‐nitro‐2,2′:5′,2″‐terthiophene 5, 3′‐nitro‐2,2′:5′,2″‐terthiophene 6 and 3‐nitro‐2,2′:5′,2″‐terthiophene 7 respectively. Preliminary results of biological acitivity are reported.
Preparation of N,N′‐di pivot lariat 1,4‐diaza‐15‐crown‐5 and 18‐crown‐6 macrocycles
Authors: An Haoyun , Bradshaw Jerald S. , Izaat Reed M.
Published: March 2009

Twelve diaza‐15‐crown‐5 and 18‐crown‐6 macrocycles containing different side arms on the nitrogen atoms have been prepared. These diaza‐N,N'‐di pivot lariat crown ethers were prepared either from N,N'‐bishydroxyethyl‐1,4‐diaza‐15‐crown‐5 or 18‐crown‐6 ligands or from the corresponding unsubstituted diaza‐crowns.
Polycyclic N‐hetero compounds. XXXV. Syntheses and anti‐platelet aggregation activity of 5,6‐Dihydro‐4H‐benzo[3,4]cyclohept[1,2‐e]imidazo[1,2‐c]pyrimidines with an oxygen function at the 1‐position
Authors: Sasaki Kenji , Sekiya Yuhki , Nagamatsu Tomohisa , Ohtomo Hiromi , Nakayama Taiji , Hirota Takashi
Published: March 2009

Various 6,7‐dihydro‐5H‐benzo[6,7]cyclohepta[1,2‐d][pyrimidines bearing amino acid group at the 4‐position of the skeleton were synthesized by the reaction of 4‐chloro‐6,7‐dihydro‐5H‐benzo[6,7]cyclohepta[1,2‐d]‐pyrimidine with some amino acid, which were cyclized to 5,6‐dihydro‐4H‐benzo[3,4]cyclohept[1,2‐e]imidazo‐[1,2‐c]pyrimidines, corresponding to B‐homo‐11,13,15‐triazasteroids. Their inhibitory activities against platelet aggregation induced by collagen were also investigated.
PolycyclicN‐hetero compounds.XXXVII. A convenient synthesis and evaluation of anti‐platelet aggregation activity of 1,2,4,5‐tetrahydro[1]‐ benzothiepino[4,5‐e]imidazo[1,2‐c]pyrimidine and its related compounds
Authors: Nagamatsu Tomohisa , Kinoshita Keiichi , Sasaki Kenji , Nakayama Taiji , Hirota Takashi
Published: March 2009

A simple and highly efficient methodology for the synthesis of 1,2,4,5‐tetrahydro[1]benzothiepino[4,5‐e]‐imidazo[1,2‐c]pyrimidine (XI) having a novel ring systemvia4‐substituted 5,6‐dihydro[1]benzothiepino‐[5,4‐d]pyrimidinesVII‐Xis described. The anti‐platelet aggregation activity for it and its related compounds against collagen‐induced aggregation of rabbit blood plateletsin vitrowas found.
The preparation of ethyl 7‐chloro‐1‐cyclopropyl‐6‐fluoro‐1,4‐dihydro‐5‐methyl‐4‐oxo‐1,8‐naphthyridine‐3‐carboxylate
Authors: Kiely John S.
Published: March 2009

Ethyl 7‐Chloro‐1‐cyclopropyl‐6‐fluoro‐1,4‐dihydro‐5‐methyl‐4‐oxo‐1,8‐naphthyridine‐3‐carboxylic acid has been prepared by a route involving masking of the C2,3 double bond through reduction, followed by regioselective deprotonation of the C5 position and methylation and then regeneration of the C2,3 double bond via selenation, oxidation, and syn‐elimination.
Cyclization reactions of 1,3‐dibromopropan‐2‐ol, 2,3‐dibromopropan‐1‐ol and 1‐bromomethyloxirane with 6‐amino‐2,3‐dihydro‐2‐thioxo‐4(1H)‐pyrimidinone
Authors: Pecorari Piergiorgio , Rinaldi Marcella , Costi Maria Paola , Antolini Luciano
Published: March 2009

The cyclization reactions, carried out in strongly‐ or weakly‐basic media, are described. Sometimes, 7‐amino‐2,3‐dihydro‐3‐hydroxymethyl‐5H‐thiazolo[3,2‐a]pyrimidin‐5‐one is separated out, together with 8‐amino‐3,4‐dihydro‐3‐hydroxy‐2H,6H‐pyrimido[2,1‐b][1,3]thiazin‐6‐one, as the principal product. A mechanism of reaction, during which the cyclizating agents are changed into oxirane derivatives, is proposed. The results of single‐crystal X‐ray investigations on 8‐amino‐3,4‐dihydro‐3‐hydroxy‐7‐nitroso‐2H,6H‐pyrimido[2,1‐b][1,3]thiazin‐6‐one (R = 0.035 for 1013 reflections), and on 7‐hydroxymethyl‐6,7‐dihydrothiazolo[3,2‐a][1,2,3]triazolo[4,5‐d]pyrimidin‐9(1H)‐one (R = 0.027 for 1607 reflections) are reported.
Synthesis of trifluoromethylthiazoles and their application to azo dyes
Authors: Tanaka Kiyoshi , Nomura Kazuto , Oda Hitoshi , Yoshida Shouhei , Mitsuhashi Keiryo
Published: March 2009

3‐Bromo‐1,1,1‐trifluoropropan‐2‐one (2) reacted with thiourea and N‐monosubstituted thioureas to give the corresponding 4‐trifluoromethylthiazoles, respectively. In the reactions with N,N'‐diphenylthiourea and thioamides, the considerably stable intermediates, 4‐hydroxy‐4‐trifluoromethylthiazoline derivatives 7 and 8, were isolated. The reaction of ethyl 2‐bromo‐4,4,4‐trifluoro‐3‐oxobutanoate (4) with thiourea was carried out under the gentle conditions to give both thiazole‐5‐carboxylate 10 and 4‐hydroxythiazoline 11. The thiazole 10 was applied to the azo dye synthesis and the absorption maxima of thus obtained azo dyes were discussed.
Synthèse et caractérisation de bis acridines pontées en positions 2, 3 ou 4
Authors: Boyer Gérard , Galy Jean‐Pierre , Barbe Jacques
Published: March 2009

Une méthode d'obtention de bis acridines pontées en position 2,2′, 3,3′ ou 4,4′ est décrite. On procède par acylation dans l'acétone des amino 2,3 ou 4 acridines. Dix bis acridines ont été caractérisées par leurs constantes physiques et par leurs paramètres de rmn du 1H et du 13C. Certaines molécules témoins ont été étudiées comme agents intercalants mais aucune n'a montré d'activité.
Synthesis of 5,6‐dihydro‐4H‐pyrrolo[1,2‐a]thieno[2,3‐f][1,4]diazepines
Authors: Vega Salvador , Gil M. Soledad
Published: March 2009

The reduction of 1‐[3‐(thienyl‐2‐carbonitrile)]pyrrole, formed by condensation of 3‐aminothiophene‐2‐carbonitrile with 2,5‐dimethoxytetrahydrofuran, gave 1‐[3‐(thienyl‐2‐aminomethyl)]pyrrole. This compound was found to be a convenient intermediate for the preparation of 4‐aryl‐5,6‐dihydro‐4H‐pyrrolo[1,2‐a]thieno‐[2,3‐f][1,4]diazepines which was accomplished by two different synthetic routes.
Reactions of a 4‐(trifluoromethyl)thiazole dianion
Authors: South Michael S. , Van Sant Karey A.
Published: March 2009

Treatment of 2‐trifluoroacetamido‐4‐(trifluoromethyl)thiazole with two equivalents of n‐butyllithium at ‐78° produced the thiazole dianion 5 in situ, which reacted preferentially at the 5‐position with a variety of electrophiles. These electrophiles include: an aldehyde, ketone, chloroformate, acid chloride, phosphorus oxychloride, silicon chloride, and disulfide. Dianion 5 also combined with dibromodifluoromethane at ‐98° to give the corresponding 5‐(bromodifluoromethyl)thiazole 7, which is an unusual reaction for an aromatic or heteroaromatic system. Compound 7 was converted to a 4,5‐bis‐(trifluoromethyl)thiazole 8 using tetrabutylammonium fluoride.
Recent work on the synthesis of 3,6‐dibenzoylcarbazole
Authors: Bonesi Sergio Mauricio , Erra‐Balsells Rosa
Published: March 2009

By heating carbazole (1) with aluminum trichloride and benzoyl chloride four benzoylcarbazole derivatives were obtained: N‐benzoylcarbazole (2), 1‐benzoylcarbazole (3), 3‐benzoylcarbazole (4) and 3,6‐dibenzoylcarbazole (5). The complete characterization of benzoylcarbazole derivatives 2–5 was performed by physical and spectroscopical methods (mp, tlc Rf, glc Tr, uv, ir, 1H nmr, 13C nmr and ms).
Nitration products of substituted 1,3‐dihydro‐5‐phenyl‐2H‐1,4‐benzodiazepin‐2‐ones
Authors: Fryer R. Ian , Gu Zi‐Qiang , Todaro L.
Published: March 2009

Highly substituted, novel, 1,3‐dihydro‐5‐phenyl‐2H‐1,4‐benzodiazepin‐2‐ones were obtained by direct nitration of the corresponding mono‐ or di‐substituted 5‐phenyl‐1,4‐benzodiazepines. Substituent effects and the orientation of aromatic substituents in the nitration products are discussed. The single‐crystal X‐ray structural data for one of these products, 18, is given.
Regioselective synthesis of 3(or 5)‐styryl‐/(4‐aryl‐1,3‐butadienyl)‐/(6‐aryl‐1,3,5‐hexatrienyl)‐5(or 3)‐(methylthio)isoxazoles and pyrazoles via α‐oxoketene dithioacetals
Authors: Purkayastha M. L. , Patro B. , Ila H. , Junjappa H.
Published: March 2009

The regioselective synthesis of the title isoxazoles and pyrazoles through cyclocondensation of oxoketene dithioacetals with either hydroxylamine or hydrazine hydrate under controlled conditions is reported.
A method for the synthesis of racemic and optically active 2‐substituted 9‐(2′,3′‐dihydroxypropyl)‐8‐azahypoxanthines and 8‐azaadenines
Authors: Barili P. L. , Biagi G. , Giorgi I. , Livi O. , Scartoni V.
Published: March 2009

Several 9‐(2′,3′‐O‐isopropylidene)‐ and 9‐(2′,3′‐dihydroxypropyl)‐8‐azahypoxanthines and 8‐azaadenines were synthesized by a “one pot” method starting from the acetonide of racemic or (S)‐1‐azido‐2,3‐dihydroxypropane, obtained from D‐mannitol. 9‐(2′,3′‐Dihydroxypropyl)‐8‐azapurines were tested as adenosine deaminase inhibitors.
Synthesis and spectral properties of 4‐oxothiazolin‐2‐yl‐[N‐R1‐2‐(para‐R2‐phenyl)indol‐3‐yl] hydrazones
Authors: Cortés Eduardo , Martínez Roberto , Gutiérrez Gómez Martha B.
Published: March 2009

The preparation of several 4‐oxothiazolin‐2‐yl‐indol‐3‐yl hydrazones is described. The structure of all products was corroborated by ir, 1H‐nmr and mass spectrometry.
Pyridazines. LIX. Synthesis of c‐annelated pyridazines from 3‐amino‐4‐pyridazinecarbonitrile
Authors: Haider Norbert , Heinisch Gottfried , Wanko Richard
Published: March 2009

The utility of the aminonitrile 1 as an educt for the preparation of several new examples of heterocyclefused pyridazines (the [1,2,4]triazolo[1′,5′:1,6]pyrimido[4,5‐c]pyridazine 7, the pyrimido[4,5‐c]pyridazines 8, 10a,b, and the pyrido[2,3‐c]pyridazine 11) is demonstrated.
A convenient synthesis of 3‐(4‐pyridinyl)quinolines
Authors: Singh Baldev , Lesher George Y.
Published: March 2009

3‐(Arylamino)‐2‐(4‐pyriclinyl)acroleins 3 prepared by reacting anilines 1 with 3‐(dimethylamino)‐2‐(4‐pyridinyl)acrolein (2) were cyclized with phosphorus oxychloride or acetic acid to give 3‐(4‐pyridinyl)quinolines 4.
Ring transformations of 1,3,4‐oxadiazol‐2(3H)‐one derivatives into 1‐amino and 1,3‐diamino‐2,4‐imidazolidinedione (hydantoin) derivatives
Authors: Milcent René , Barbier Géo , Yver Béatrice , Mazouz Fathi
Published: March 2009

Some ethyl 5‐aryl(or benzyl)‐2‐oxo‐1,3,4‐oxadiazole‐3(2H)‐acetates were prepared and treated with ammonia, primary amines or hydrazine to give 1‐amino‐2,4‐imidazolidinedione or 1,3‐diamino‐2,4‐imidazolidinedione derivatives. The 1,3‐bis(benzylideneamino)‐2,4‐imidazolidinedione was obtained by reacting ethyl bromoacetate with the 1,5‐dibenzylidenecarbonohydrazide sodium salt.
Stability of naturally occurring pyrazines and construction route of pyrazine rings
Authors: Kurihara Teruo , Watanabe Yutaka , Takayama Kouichi , Ohta Akihiro
Published: March 2009

Naturally occurring pyrazines fit well the theory that conformity to the TCS rule gives a stable molecular system. Thus, many pyrazines so far synthesized and those in nature which are energetically very stable molecules can be synthetically quite accessible. The TCS rule applies very well to the construction route of pyrazine rings.
Synthesis of 2,5‐diisoxazolyltetrahydrofurans
Authors: Chiarino D. , Fantucci M.
Published: March 2009

The synthesis of 2,5‐bis(3‐bromo‐5‐isoxazolyl)tetrahydrofuran (2) and 2,5‐bis(3‐methoxy‐5‐isoxazolyl)tetrahydrofuran (3) have been accomplished in three and four steps respectively.Cis‐ andtrans‐isomers have been separated and fully characterized. Differently from synthetic schemes so far utilized for the preparation of the 2,5‐diheteroaryltetrahydrofuran analogs, our approach involves the direct synthesis of a key intermediate containing both isoxazole rings and diol function for the final cyclization. Starting from succinic aldehyde, the new 1,7‐octadiyne‐3,6‐diol (4) was prepared and was submitted to a double cycloaddition with bromonitrile oxide to yield the key intermediate 1,4‐bis(3‐bromo‐5‐isoxazolyl)‐1,4‐butanediol. The methoxy analogs3were obtained by methanolysis of the bromo derivatives2.
Synthesis and properties of 5‐aroylamino‐2H‐1,2,4‐thiadiazol‐3‐ones
Authors: Cho Nam Sook , Shon Hyun Il , Párkányi Cyril
Published: March 2009

5‐Aroylamino‐2H‐1,2,4‐thiadiazol‐3‐ones 3 were obtained from the corresponding 1‐aroyl‐2‐thiobiurets 2 by oxidative cyclization with bromine. 5‐Aroylamino‐2H‐1,2,4‐thiadiazol‐3‐ones 3 can exist in two tautomeric forms a lactam form and a lactim form. On the basis of the 13C nmr spectra and additional experimental information, it has been established that the stable form, in which these compounds exist, is the lactam form.
Reactions of trichloroacetyl isothiocyanate with organic azides
Authors: L'Abbé Gerrit , Bosnian Joris , Toppet Suzanne
Published: March 2009

Benzyl azide reacts with trichloroacetyl isothiocyanate to give 7a in chloroform solution, and 11 in acetone solution. These 1,2,4‐oxathiazolidines were characterized by 13C nmr spectroscopy (Scheme 2), but could not be isolated since they deteriorated via the carbodiimide 8a into the 1,2,4‐thiadiazolidine 9a. The oxathiazoline 6a is assumed as an intermediate and was trapped by isocyanates and dicyclohexylcarbodiimide to give the 1,2,4‐thiadiazolidines 10a,b and 12 respectively. Isopropyl azide also reacts with trichloroacetyl isothiocyanate to give the labile oxathiazolidine 7b, which decomposes to the carbodiimide 8b and the 1,2,4‐thiadiazolidine 9b. In the case of diphenylmethyl azide, however, no evidence was obtained for the presence of the oxathiazolidine 7c in the 1H nmr spectra; only the carbodiimide 8c was observed. A mechanistic rationalization is presented in Scheme 1.
1,2‐fused pyrimidines. V. Synthesis of 1‐alkyl or phenyl‐2H‐dipyrido‐[1,2‐a:2′,3′‐d]pyrimidine‐2,5(1H)‐diones
Authors: Di Braccio Mario , Roma Giorgio , Grossi Gian Carlo , Ciarallo Giovanni
Published: March 2009

The reaction of 2‐[(N‐acyl, N‐alkyl or phenyl)amino]‐4H‐pyrido[1,2‐a]pyrimidin‐4‐ones 8a‐g with the N,N‐dimethylformamide/phosphorus oxychloride Vilsmeier reagent 1 (95°, 90 minutes) afforded 1‐alkyl or phenyl‐2H‐dipyrido[1,2‐a:2′,3′‐d]pyrimidine‐2,5(1H)−diones, 3‐alkyl substituted or not, 10a‐g.

The starting compounds 8 were prepared by treating 2‐amino‐4H‐pyrido[1,2‐a]pyrimidin‐4‐ones N‐alkyl substituted 7a,b or N‐phenyl substituted 4 with excess anhydrides (130°, 7 hours) when the 2‐(alkylamino) derivatives 7 were used in the reaction, compounds 8 were obtained along with very small amounts of 3‐acyl‐2‐(alkylamino)‐4H‐pyrido[1,2‐a]pyrimidin‐4‐ones 9.
Synthesis of 1,3‐disubstituted‐5‐oxo‐7a‐methyl‐5,7a‐dihydroindoles
Authors: Player Mark R. , Wang Li‐Chang , Bayomi Said M. , Sowell J. Walter
Published: March 2009

Cycloaddition and addition reactions of ethyl propiolate with a series of 1,3,5‐substituted‐2‐amino‐4‐methylpyrroles to form, 1,3‐disubstituted‐5‐oxo‐7a‐methyl‐5,7a‐dihydroindoles are described. High resolution mass spectral and pmr data are presented.
Synthesis of molybdenum(V) and molybdenum(VI) derivatives of 5,15‐diphenyl‐2,8,12,18‐tetra‐n‐butyl‐3,7,13,17‐tetramethylporphyrin
Authors: Van Dijk Marinus , Morita Yashuo , Petrović Slobodan , Sanders Georgine M. , Van Der Plas Henk C. , Stam Casper H. , Wang Yuanfang
Published: March 2009

The methoxo‐oxomolybdenum(V), diperoxomolybdenum(VI) and cis‐dioxomolybdenum(VI) derivatives of 5,15‐diphenyl‐2,8,12,18‐tetra‐n‐butyl‐3,7,13,17‐tetramethylporphyrin (4a, 5c, 6a) have been prepared and characterized by uv, ir, pmr, mass and esr spectra. The structure of the molybdenum(V) porphyrin was confirmed by X‐ray analysis.
Enzymatic hydrolysis of heterocyclic nitriles
Authors: Klempier Norbert , De Raadt Anna , Griengl Herfried , Heinisch Gottfried
Published: March 2009

Chemoselective hydrolysis of heterocyclic nitriles can be achieved by an easy to use immobilized biocatalyst prepared from Rhodococcus sp. Pyrimidine‐2‐carbonitrile (2a) and 3‐chloropyridazine‐4‐carbonitrile (4a) were converted into the corresponding amides while from 2‐ethoxycarbonyl‐4‐pyridinecarbonitrile (1a), 6‐methylpyridazine‐3‐carbonitrile (3a), 3‐chloropyridazine‐4‐carbonitrile (4a), 3‐ethoxycarbonyl‐4,5‐dihydroisoxazole‐5‐carbonitrile (8a), indole‐3‐carbonitrile (9a) and indole‐3‐ylacetonitrile (10a) the acids were formed.
Synthesis and photochemical reaction of 1,4‐dialkyl‐7‐oxa‐2,3,5,6‐tetrakis(trifluoromethyl)bicyclohepta‐2,5‐diene
Authors: Nishida Masakazu , Hayakawa Yoshio , Matsui Masaki , Shibata Katsuyoshi , Muramatsu Hiroshige
Published: March 2009

Diels‐Alder reaction of 2,5‐dialkyl‐3,4‐bis(trifluoromethyl)furan with hexafluoro‐2‐butyne gave 1,4‐dialkyl‐7‐oxa‐2,3,5,6‐tetrakis(trifluoromethyl)bicyclohepta‐2,5‐diene. Irradiation (uv) of 1,4‐diethyl‐7‐oxa‐2,3,5,6‐tetrakis(trifluoromethyl)bicyclohepta‐2,5‐diene afforded 1‐ethyl‐2,3,4,5‐tetrakis(trifluoromethyl)‐1,4‐cyclopentadiene, ethyl 3‐[l‐ethyl‐2,3,4,5‐tetrakis(trifluoromethyl)‐1,4‐cyclopentadienyl] ketone, and 2,7‐diethyl‐3,4,5,6‐tetrakis(trifluoromethyl)oxepin.
Convenient preparation of 1,2‐alkylenedioxy‐benzofuroxans and benzofurazans
Authors: Takakis Ioannis M. , Hadjimihalakis Phaedon M. , Tsantali Georgia G. , Pilini Helena
Published: March 2009

Nitration of the dioxolo‐annelated benzenes 11 led to the corresponding dinitro derivatives 12. Nucleophilic substitution of the latter with azide ion furnished the monoazides 13 which on thermolysis afforded the benzofuroxans 14. Deoxygenation of furoxans 1a,b,e,f, 2a‐c,e,f, 5, 7, 9 and 14 with triphenylphosphine, furnished the respective benzofurazans 3a,b,e,f, 4a‐c,e,f, 6, 8, 10 and 15.
Benzoin condensation reactions of 5‐membered heterocyclic compounds
Authors: Lee Chang Kiu , Kim Mi Soon , Gong Jin Soon , Lee In‐Sook Han
Published: March 2009

Benzoin condensation reactions of 2‐thiophenecarboxaldehydes and furfurals have been reexamined with catalysts such as potassium cyanide, cyanide‐resin, and a thiazolium salt. 2‐Thiophenecarboxaldehydes gave both thenoins and thenils while furfurals gave only furoins. Possible routes which might lead to formation of thenils were investigated.
Lithiation of 1‐alkyl‐1H‐1,2,4‐triazol‐5‐yl phosphonic acid esters: Novel anion‐mediated carbon‐to‐carbon phosphonate migrations
Authors: Anderson D. Keith , Sikorski James A.
Published: March 2009

The lithiation chemistry of 1‐alkyl‐1H‐1,2,4‐triazol‐5‐yl phosphonic acid esters 3 has been investigated. Lithiation occurs exclusively on the 1‐alkyl group, α to nitrogen, to give carbanionic intermediates 10. No evidence was found for any lithiation at the 3‐position of the triazole ring. On warming, intermediates 10 undergo an unusual anion‐mediated phosphonate migration, giving rise to 1H‐1,2,4‐triazol‐1‐yl‐methylphos‐phonates 14.
Synthesis and reactions of methylbenzo[c]quinolizinium salts
Authors: Arai Sadao , Arai Hitoshi , Tabuchi Kunihisa , Yamagishi Takamichi , Hida Mitsuhiko
Published: March 2009

Six isomers of the methylbenzo[c]quinolizinium salt 3 including four new monomethyl derivatives were synthesized by thermal‐intramolecular quaternization of the cis‐methyl‐substituted 2‐[2‐(2‐chlorophenyl)‐vinyl]pyridines 4 or by the irradiation of trans‐4 with selected wavelengths (290 < λ < 340 nm and λ > 400 nm) in acetonitrile. Among the regioisomeric monomethyl derivatives 3, the 1‐, 3‐, and 6‐methyl derivatives 3b, 3d, and 3g reacted with p‐methoxybenzaldehyde in the presence of bis(l‐piperidino)‐(p‐methoxyphenyl)‐methane 7 to yield trans‐(p‐methoxystyryl)benzo[c]quinolizinium salts 6. The reactivity of 3 and methylbenzo[a]quinolizinium salts 1 was discussed on the basis of their π‐electron energy.
Preparation of uracil by cycloreversion. Structure of cycloalkane/ene‐ and norbornane/ene‐fused dihydrouracils
Authors: Frimpong‐Manso Samuel , Nagy Katalin , Stájer Géza , Bernáth Gábor , Sohár Pál
Published: March 2009

The reactions of the 2‐amino‐1‐cycloalkane‐, cycloalkene‐, norbornane‐ and norbornenecarboxylates 1–9 with potassium cyanate gave urea esters, which were cyclized to cycloalkane‐, cycloalkene‐, norbornane‐ and norbornene‐fused 5,6‐dihydrouracils 10–17. On cyclization, the urea ester formed from trans‐4‐cyclohexene‐1‐carboxylate, furnished the cis‐fused 5,6‐dihydropyrimidine‐2,4(1H,3H)‐dione. On heating, the norbornene‐diexo‐fused dihydrouracil 16 yielded 2,4‐pyrimidinedione through the splitting‐off of cyclopentadiene. The structures of the compounds were proved by 1H and 13C nmr spectroscopy.
Nucleophilic substitution and ring closure reactions of 4‐chloro‐3‐nitro‐2‐quinolones
Authors: Roschger Peter , Fiala Werner , Stadlbauer Wolfgang
Published: March 2009

4‐Chloro‐3‐nitro‐2‐quinolones 3 obtained from the 4‐hydroxy quinolones 1 by nitration and chlorination, reacted with sodium azide to the 4‐azido derivatives 4 which cyclized on thermolysis to yield the furoxanes 5. Nucleophilic substitution reactions of 3 led to the 4‐amino‐, 4‐fluoro‐ and 4‐alkoxy‐3‐nitroquinolones 7, 8 and 9, respectively. With thiols either 4‐thio‐3‐nitro‐ 10 or 3,4‐dithioquinolones 11 were obtained depending on the basic catalyst.
Thiophene systems. 13. The synthesis of novel thienopyranones
Authors: Mcnally James J. , Sanfilippo Pauline J. , Fitzpatrick Louis , Press Jeffery B.
Published: March 2009

The syntheses and spectral properties of novel dimethyl‐substituted thieno[3,2‐b]‐, [3,4‐b]‐ and [2,3‐b]pyran‐ones are described. The uv spectra of the three systems are distinctly different as supported by HOMO/LUMO calculations. 5,6‐Dihydro‐5,5‐dimethyl‐7H‐thieno[3,4‐b]pyran‐7‐one (10) and 5,6‐dihydro‐6,6‐dimethyl‐4H‐thieno[2,3‐b]pyran‐4‐one (20) represent the first members of these thienopyranone ring systems.
Decomposition of cinnabarinic acid by hydrogen peroxide
Authors: Manthey Michael K. , Pyne Stephen G. , Truscott Roger J. W.
Published: March 2009

The hydrogen peroxide‐induced decomposition of cinnabarinic acid 2 has been examined. Two major compounds were found to arise from the decomposition; 3‐hydroxyanthranilic acid 1, and an isomeric mixture of two novel hemiketals.
Enantiomers and barriers to racemization of sterically hindered N‐aryl‐ and N‐heteroarylpyrroles
Authors: Vorkapić‐Furač Jasna , Mintas Mladen , Kastner Fritz , Mannschreck Albrecht
Published: March 2009

The N‐aryl‐ and N‐heteroaryl‐2,5‐dimethylpyrrole‐3‐carbaldehydes 2–8 have been synthesized by condensation of hexane‐2,5‐dione with the appropriate amine and subsequent Vilsmeier‐Haack formylation of the pyrrole ring. Diastereomeric association complexes of the racemic pyrrole 8 were studied by pmr chemical shifts and the splittings induced by (+)‐1‐(9‐anthryl)‐2,2,2‐trifluoroethanol. Enrichment of the enantiomers M and P of 2 and 6 was achieved by liquid chromatography on triacethylcellulose. The barrier to partial rotation about the C‐N bond in 6 was determined by thermal racemization and its lower limits in 2 and 8 were estimated.
Products from furans.XXISynthesis of novel oxygen containing heterocyclic isosteres of tyrosine derivatives
Authors: Georgiadis Minas P. , Haroutounian Serkos A.
Published: March 2009

Novel oxygen containing heterocyclic isosteres of tyrosine and tyramine derivatives were synthesized. All new compounds contain the pyran ring as a consequence of their common route of preparation. Furthermore several methyl, ethyl, diethyl and isopropyl derivatives of the prepared amines were synthesized.