bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the chichibabin amination of pyrimidine and N‐alkylpyrimidinium salts using liquid ammonia/potassium permanganate
Authors: Buurman Dick J. , Van Der Plas Henk C. 
Published: April 2009

AbstractTreatment of the 2‐R‐pyrimidines (1, R = methyl, ethyl, i‐propyl and t‐butyl) with potassium amide/liquid ammonia/potassium permanganate leads to amination at C‐4(6). The yields of the 4(6)‐amino compounds 3 in‐crease in the order 2‐methyl (10%), 2‐ethyl (30%), 2‐i‐propyl (45%) and 2‐t‐butyl (60%). Treatment of the 2‐R‐N‐methylpyrimidinium salts (4, R = hydrogen, methyl) with liquid ammonia/potassium permanganate leads to a regiospecific imination at C‐6, the corresponding 2‐R‐1,6‐dihydro‐6‐imino‐1‐methylpyrimidines 6 being obtained in 80‐85% yield. It is proved by 15N‐labelling that no ring opening is involved in these imination reactions. Treatment of the imino compounds with base leads to the corresponding 2.R‐6‐methylamino‐pyrimidines 8, involving, as proved by 15N‐labelling, an ANRORC‐mechanism. 2‐t‐Butyl‐1‐ethylpyrimidinium tetrafluoroborate (9b) when treated with liquid ammonia/potassium permanganate undergoes N‐deethylation, 2‐t‐butylpyrimidine being exclusively formed.
Intramolecular cyclization of 4‐aryl‐1,4‐dihydropyridine acetals
Authors: Hartman George D. , Phillips Brian T. , Springer James P. , Hirshfield Jordan 
Published: April 2009

AbstractThe synthesis of 4‐aryl‐1,4‐dihydropyridines possessing a protected aldehyde functionality at the ortho position is described. These compounds undergo iminium ion mediated cyclization when treated with titanium tetrachloride or gaseous hydrogen chloride. Mechanistically, cyclization utilizes attack of C‐3 of the dihydropyridine on the electrophilic species generated from complexation of the acetal. This methodology highlights opportunities for the construction of novel conformationally constrained dihydropyridine analogs.
Some reactions of 1‐methyl‐(2‐phenylethyl)‐1,2,3,4‐tetrahydropyridines with organic azides. Synthesis of 1‐methyl‐(2‐phenylethyl)piperidylidene‐2‐sulfonamides
Authors: Warren Brent K. , Knaus Edward E. 
Published: April 2009

AbstractThe 1,3‐dipolar cycloaddition reaction of 1‐methyl‐ and 1‐(2‐phenylethyl)‐1,2,3,4‐tetrahydropyridines 7 with organic azides 8 afforded the respective 1‐substituted‐piperidylidene‐2‐sulfon(cyan)amides 9. Nitration of the 1‐(2‐phenylethyl) analogue 9o yielded the 1‐[2‐(4‐nitrophenyl)ethyl] derivative 9r which on reduction with palladium‐on‐charcoal and hydrazine gave the 1‐[2‐(4‐aminophenyl)ethyl] analogue 9s.
On the reaction of 2‐chloroethylisothiocyanate with aromatic amines
Authors: Outcalt Russell J. 
Published: April 2009

AbstractThe reaction of aromatic amines with 2‐chloroethylisothiocyanate 2 to give 2‐arylaminothiazolines 1 was investigated. The course of this reaction was found to depend on the electronic nature of the amine and the reaction conditions. With arylamines that are relatively electron‐rich, good yields of the thiazolines 1 were obtained. With electron‐poor amines, adducts 4, in which two equivalents of 2 reacted with the amine, accompanied 1. The relative amounts of 2:1 adducts increased as the arylamine became progressively more electron deficient. With 3,4‐dichloroaniline, the yields of the 2:1 adducts were promoted by the presence of triethylamine.
The synthesis of 6,6′‐cyclo‐6′‐deoxyhexofuranosyluracils via a diazomethane‐promoted ring‐enlargement reaction
Authors: Sasson Isaac M. , Otter Brian A. 
Published: April 2009

AbstractThe protected 5′‐oxo‐6,5′‐cyclouridine 13 reacts with diazomethane to afford mostly the spiro‐epoxide 18 (79%), but it also undergoes ring‐expansion to give the corresponding 5′‐oxo‐6,6′‐cyclonucleoside 16. Under the conditions of the reaction, ketone 16 reacts further with diazomethane to give the enol ether 20 (12% overall), the isomeric 4‐methoxy nucleoside 15 (2%), and the spiro‐epoxide 19 (4.4%). Acid hydrolysis of the enol ether 20, followed by reduction of the resulting ketone with sodium borohydride, affords a separable mixture of the 5′S (L‐talo) and 5′R (D‐allo) methylene‐bridged cyclonucleosides 7 and 8, respectively. From proton nmr measurements, it appears that the 6′‐methylene groups of these cyclonucleosides project towards the 2′,3′‐edge of the furanose ring.
Heterocyclic systems. VIII. synthesis of 1H,4H‐pyrazolo[4,3‐f]pyrrolo[1,2‐a]azepine derivatives
Authors: Corelli Federico , Massa Silvio , Stefancich Giorgio , Silvestri Romano 
Published: April 2009

AbstractThe synthesis of the unknown title Compounds is described. The preparation involves intramolecular acylation of 3‐[1‐phenyl‐5‐(1‐pyrryl)pyrazol‐4‐yl]propanoic acid 9 to the tricyclic ketone 10, which was then transformed into 1H,4H‐pyrazolo[4,3‐f]pyrrolo[1,2‐a]azepine 12 and its dihydro derivative 13 by reductive procedures.
An improved synthesis of pyrido[2,3‐d]pyrimidines
Authors: Itoh Tsuneo , Fujii Ikuko , Tomii Yasuo , Ishikawa Ichiro , Ogura Hamo , Mizuno Yoshihisa , Kawahara Norio 
Published: April 2009

AbstractAn improved and efficient synthesis of 1,3‐dialkylpyrido[2,3‐d]pyrimidine‐2,4‐(1H,3H)‐diones from 6‐methylaminouracils and methyl propiolate or diethyl ethoxymethylenemalonate is described.
Studies on decarboxylation reactions. Part 6. Kinetic study of decarboxylation of 5‐amino‐1,3,4‐oxadiazole‐2‐carboxylic acid and its N‐phenyl derivatives at high hydrochloric acid concentrations
Authors: Noto Renato , Werber Giuseppe , Buccheri Francesco , Arnone Caterina 
Published: April 2009

AbstractThe dissociation constants (K1) of both acids 4a‐c and esters 5a‐c and the rate constants of the decarboxylation reaction of acids 4a‐c have been measured at various high concentrations of hydrochloric acid (0.5‐8.0 M range). The results obtained have enabled us to suggest the probable structure of the zwitterion which undergoes decarboxylation.
Saturated heterocycles. 136 . Synthesis of 2‐substituted 2‐azapyracridone derivatives
Authors: Huber Imre , Fülöp Ferenc , Bernáth Gábor , Hermecz István 
Published: April 2009

AbstractBy means of Substitution, addition and condensation on the secondary nitrogen of 9‐methyl‐1,2,3,4‐tetrahydro‐2‐azapyracridone (6), twenty new azapyracridones were prepared.
The effect of the steric requirements of trialkylsilyl ethers on ring closure of 1‐(benzylamino)‐3‐chloro‐2‐(trialkylsiloxy)propanesd
Authors: Higgins Robert H. 
Published: April 2009

AbstractThe ring closure of 1‐(benzylamino)‐3‐chloro‐2‐(trialkylsiloxy)propanes to 1‐benzyl‐3‐(trialkylsiloxy)azetidines was investigated. There appears to be little or no advantage in the use of trialkylsilyl substituents larger than trimethylsilyl.
New 7‐substituted quinolone antibacterial agents. The synthesis of 1‐ethyl‐1,4‐dihydro‐4‐oxo‐7‐(2‐thiazolyl and 4‐thiazolyl)‐3‐quinolinecarboxylic acids
Authors: Culbertson Townley P. , Domagala John M. , Peterson Phred , Bongers Shannon , Nichols Jeffrey B. 
Published: April 2009

AbstractA series of 1‐ethyl‐1,4‐dihydro‐4‐oxo‐7‐(4‐thiazolyl)‐3‐quinolinecarboxylic acids and 1‐ethyl‐1,4‐dihydro‐4‐oxo‐7‐(2‐thiazolyl)‐3‐quinolinecarboxylic acids were prepared. Also prepared was 10‐[2‐(aminomethyl)‐4‐thiazolyl]‐9‐fluoro‐2,3‐dihydro‐3‐methyl‐7‐oxo‐7H‐pyrido[1,2,3‐de][1,4]benzoxazine‐6‐carboxylic acid. Analogs with basic amine substituents on the thiazole moiety were found to have antibacterial activity.
Reaction of acetone oxime with dialkylmalonyl chlorides. Synthesis of 2‐(2‐propenyl)isoxazolidine‐3,5‐diones and 2,2‐bis‐(2‐(4,4‐dialkylisoxazolidine‐3,5‐dione))propanes
Authors: Izydore Robert A. , Davis Ronda G. , Clements Nancy W. 
Published: April 2009

AbstractReaction of acetone oxime with dialkylmalonyl chlorides in the presence of triethylamine gave as products 2‐(2‐propenyl)‐4,4‐dialkylisoxazolidine‐3,5‐diones 4 and 2,2‐bis‐(2‐(4,4‐dialkylisoxazolidine‐3,5‐dione))propanes 5. The 4,4‐dialkylisoxazolidine‐3,5‐diones 6 and dimethylketoximyl 4,4‐dialkylmalonates 7 were formed as minor products. Compounds 4 are stable in refluxing ethanol and in aqueous solution. Compounds 5 are stable when heated in refluxing toluene in the presence of either pyridine or monochloroacetic acid.
Sulfonylcarbamimidic azides from sulfonyl chlorides and 5‐aminotetrazole
Authors: Peet Norton P. , Sunder Shyam , Barbuch Robert J. , Huber Edward W. , Bargar Ester M. 
Published: April 2009

AbstractTreatment of o‐nitrobenzenesulfonyl chloride (3) with 5‐aminotetrazole (5‐AT) gave [(2‐nitrophenyl)‐sulfonyl]carbamimidic azide (6), a ring‐opened isomer of the expected N‐(1H‐tetrazol‐5‐yl)‐2‐nitrobenzenesulfonamide (4). Sulfonylcarbamimidic azide 6 was converted to 2‐amino‐N‐(aminoiminomethyl)benzene‐sulfonamide (7) with ethanolic stannous chloride, and to 3‐amino‐1,2,4‐thiadiazine 1,1‐dioxide (8) with sodium dithionite. Methanesulfonyl chloride (9) and 5‐AT gave 2‐(methylsulfonyl)carbamimidic azide (10), which isomerized to 5‐[(methylsulfonyl)amino]‐1H‐tetrazole (11) in warm ethanol. Attempted cycloaddition of 2‐(phenylsulfonyl)carbamimidic azide (13) and ethyl vinyl ether led only to alkylated tetrazole products. In addition, other tetrazole‐alkylating reactions are described. Isomers produced from these alkylations were differentiated with 13C nmr spectroscopy.
Synthesis of indole derivatives from 2‐bromoanilines by a palladium‐assisted reaction
Authors: Kasahara Akira , Izumi Taeko , Kikuchi Tokio , Xiao‐Ping Lin 
Published: April 2009

AbstractIn the presence of palladium(II) acetate, 2‐bromoanilines readily react with enamines such as N‐vinyl‐pyrrolidone or α‐piperidinostyrene to produce indole derivatives.
The synthesis of dimethoxy‐ and trimethoxy[1]benzothieno[2,3‐c]quinolines
Authors: Stuart John G. , Khora Shinya , McKenney J. Dew , Castle Raymond N. 
Published: April 2009

AbstractThree dimethoxy[1]benzothieno[2,3‐c]quinolines 24–26 were prepared by photocyclization of the appropriate 3‐chloro‐N‐phenylbenzo[b]thiophene‐2‐carboxamides 15–17 to [1]benzothieno[2,3‐c]quinolin‐6(5H)‐ones 18–20 followed by chlorination to 6‐chloro[1]benzothieno[2,3‐c]quinolines 21–23 and then dechlorination resulting in the title compounds. Reaction of 24–26 with methyl iodide furnished the corresponding N‐methyl quaternary salts 27–29. Sodium methoxide readily converted 21–23 to trimethoxy[1]benzothieno[2,3‐c]quinolines 30–32.
Tetracyclic benzodiazepines. 4. Synthesis of the novel benzo[c]pyrrolo[1,2,3‐ef][1,5]benzodiazepine ring system, and derivatives with potential antipsychotic activity
Authors: Glamkowski Edward J. , Chiang Yulin 
Published: April 2009

AbstractThe synthesis of the novel benzo[c]pyrrolo[1,2,3‐ef][1,5]benzodiazepine ring system is described. This was achieved by cyclization of an appropriately substituted (7‐aminoindolin‐1‐yl)benzamide or benzoic acid. The resulting tetracyclic lactams were reacted with N‐methylpiperazine in the presence of titanium tetrachloride to provide derivatives which were tested for potential antipsychotic activity.
Sels de N‐alcoxyquinoléinium et d'isoquinoléinium porteurs d'une fonction cétone dans leur chaîne alcoxyle: Synthèse et réactivité vis‐à‐vis d'amines secondaires
Authors: Sliwa Henri , Ouattara Lassina 
Published: April 2009

AbstractLes sels d'α (quinoléine‐1 oxy) et α (isoquinoléine‐1 oxy) isobutyrophénone ont été préparés par action de l'α‐bromoisobutyrophénone sur les N‐oxydes hétérocycliques correspondants, en présence de perchlorate d'argent. L'action d'amines secondaires sur ces sels permet d'accéder, avec d'excellents rendements, respectivement à la benzoyl‐2 quinoléine et à la benzoyl‐1 isoquinoléine. Ces réactions s'interprétent par la formation d'un dérivé tricyclique isoxazolo[2,3‐a]quinoléinium ou isoquinoléinium subissant une décomposition alcoxylogue du mode A de la classification de Katritzky.
Unequivocal syntheses of 6‐methyl‐ and 6‐phenylisoxanthopterin
Authors: Neilsen J. Bryant , Broadbent H. Smith , Hennen William J. 
Published: April 2009

AbstractAlthough 6‐methyl‐ (1) and 6‐phenylisoxanthopterin (2) have previously been synthesized, the requirement of high purity necessary for immunological testing has necessitated our development of the first reported synthesis of these compounds by unequivocal methods. In the process of so doing four new pyrazines, ethyl 3‐amino‐5‐chloro‐6‐methyl‐2‐pyrazinecarboxylate (11), N,N‐dimethyl‐N'‐(6‐chloro‐3‐cyano‐5‐phenylpyrazin‐2‐yl)methanimidamide (16), 2‐amino‐3‐ethoxycarbonyl‐5‐phenylpyrazine 1‐oxide (19), and ethyl 3‐amino‐5‐chloro‐6‐phenyl‐2‐pyrazinecarboxylate (20) were synthesized. Four new pteridines, 7‐methoxy‐6‐methyl‐2,4‐pteridinediamine (7), 7‐methoxy‐6‐phenyl‐2,4‐pteridinediamine (17), 2‐amino‐7‐ethoxy‐6‐methyl‐4(3H)‐pteridinone (12), and 2‐amino‐7‐ethoxy‐6‐phenyl‐4(3H)‐pteridinone (21) have also been synthesized enroute to these isoxanthopterins.
Synthesis and antileukemic activity of spiro[indoline‐3,2′‐thiazolidine]‐2,4′‐diones
Authors: Rajopadhye Milind , Popp F. D. 
Published: April 2009

AbstractA number of spiro[indoline‐3,2′‐thiazolidine]‐2,4′‐diones have been prepared via the cyclocondensation of isatin‐3‐imines with α‐mercaptoacids. 1‐Benzyl‐5′,5′‐dimethylspiro[indoline‐3,2′‐thiazolidine]‐2,4′‐diones were prepared by simultaneously refluxing 1‐benzylisatin, α‐mercaptoisobutyric acid and various anilines in toluene. 3′‐(4‐Chlorophenyl)‐5,5′‐dimethylspiro[indoline‐3,2′‐thiazolidine]‐2,4′‐dione was active in the P388 and the L1210 leukemia screen tests. A number of analogs of the active spiro compound have been prepared and submitted for antileukemic screening. Anticonvulsant screening results of related compounds are also included.
The regiospecific synthesis of the A and B rings of phomazarin
Authors: Guay Vincent , Brassard Paul 
Published: April 2009

AbstractElaboration of the A ring of phomazarin by the Conrad‐Limpach approach has been shown to be possible in the case of a protected hydroquinone substrate. However similar condensations using a suitably substituted naphthoquinone gave a lactam instead of the expected benzoquinolone. Attempts to annulate simplified models of the A‐B rings with the appropriate diene have also been successful albeit in low yield.
On the amination of pyrimido[5,4‐e]1,2,4‐triazines in liquid ammonia
Authors: Brouwer A. C. , van der Plas H. C. 
Published: April 2009

AbstractWhen dissolved in liquid ammonia 5‐chloro‐1,2‐dihydropyrimido[5,4‐e]‐1,2,4‐triazine (1) and 5‐methoxy‐pyrimido[5,4e]‐1,2,4‐triazine (4) quickly convert into 5‐aminopyrimido[5,4‐e]‐1,2,4‐triazine (2). When 2 is kept in liquid ammonia containing an excess of potassium permanganate, 3,5‐diaminopyrimido[5,4‐e]‐1,2,4‐triazine (5) is formed.
Synthesis of hydrazones derived from 2‐substituted‐10‐carboxyphenothiazine hydrazides
Authors: Tsitsa P. , Psarrea‐Sandris A. , Sandris C. 
Published: April 2009

Abstract2‐Substituted‐10‐carboxyphenothiazine hydrazides 3 were found to yield hydrazones 5 on reaction with aromatic aldehydes. However, a similar reaction of hydrazides 3 with aliphatic ketones in refluxing ethanol failed to give the expected hydrazones 6. The corresponding phenothiazines 1 were isolated in this reaction, apparently through alcoholysis of the amide bond to the ring nitrogen atom in 3.
Reaction of 2‐dimethylaminomethylene‐1,3‐diones with dinucleophiles. VI. Synthesis of ethyl or methyl 1,5‐disubstituted 1H‐pyrazole‐4‐carboxylates
Authors: Menozzi Giulia , Mosti Luisa , Schenone Pietro 
Published: April 2009

AbstractReaction of ethyl or methyl 3‐oxoalkanoates with N,N‐dimethylformamide dimethyl acetal gave, generally in excellent yields, a series of ethyl or methyl 2‐dimethylaminomethylene‐3‐oxoalkanoates II which reacted with phenylhydrazine to afford the esters of 5‐substituted 1‐phenyl‐1H‐pyrazole‐4‐carboxylic acids III in high yields. Esters III were hydrolyzed to the relative 5‐substituted 1‐phenyl‐1H‐pyrazole‐4‐carboxylic acids which were converted by heating to 5‐substituted 1‐phenyl‐1H‐pyrazoles in excellent yields. Reaction of II with methylhydrazine afforded in general a mixture of 3‐ and 5‐substituted ethyl 1‐methyl‐1H‐pyrazole‐4‐carboxylates with the exception of IIg, which gave in high yield methyl 5‐benzyl‐1‐methyl‐1H‐pyrazole‐4‐carboxylate, which was hydrolyzed to the relative pyrazolecarboxylic acid. This afforded by heating 5‐benzyl‐1‐methyl‐1H‐pyrazole in quantitative yield.
Studies on heterocyclic enamines: New syntheses of 4H‐pyranes, pyranopyrazoles and pyranopyrimidines
Authors: Elnagdi Mohamed Hilmy , Abdel‐Motaleb Ramadan Maawad , Mustafa Mona , Zayed Mohamed Foad , Kamel Eman Moustafa 
Published: April 2009

AbstractThe behaviour of several 2‐amino‐3‐cyano‐4H‐pyran derivatives toward a variety of nucleophilic reagents is reported.
The reaction between 2‐aminobenzenethiol and diethyl oxalate. A structural reassegnement
Authors: Liso Gaetano , Trapani Giuseppe , Latrofa Andrea 
Published: April 2009

AbstractIt is proposed that the reported [2] condensation between 2‐aminobenzenethiol and diethyloxalate give rise to 2‐ethoxycarbonylbenzothiazole 3 rather than 3‐ethoxy‐2H‐1,4‐benzothiazin‐2‐one 2.
On triazoles. XII. The carbamoylation and thiocarbamoylation of 5‐amino‐1,2,4‐triazoles
Authors: Reiter József , Pongó László , Dvortsák Péter 
Published: April 2009

AbstractThe reaction of 5‐amino‐3‐R‐1H‐1,2,4‐triazoles 1 with isocyanates 2 (X = O) and isothiocyanates 2 (X = S) was studied. It was stated that with isocyanates 3a (X = O) type ring‐carbamoylated products were formed which did not rearrange to the corresponding exo‐carbamoylated derivatives 6a (X = O). On the other hand the thiocarbamoylation of derivatives 1 provided at mild conditions lead to derivatives 3a (X = S) which could be rearranged by heating to derivatives 6a (X = S). In one case the isomeric 4a (X = S) type derivative was also isolated. The comparison of the ir, uv, pmr and cmr spectra of the isomers isolated with the corresponding spectra of the carbamoylated and thiocarbamoylated 3,5‐diamino‐1,2,4‐triazole derivatives helped to prove unequivocally the isomeric and tautomeric structure of compounds obtained giving a possibility to correct many confusions in the literature.
Antikonvulsiva,II. Die cyanethylierung im system des butyroguanamins
Authors: Kreutzberger Alfred , Loch Michael 
Published: April 2009

AbstractDie die Anlagerung von Acrylnitril (2) beinhaltende Cyanethylierung des Butyroguanamins (1) führt zu den cyanethylierten Propyl‐1,3,5‐triazinen3, 4und5. Spektroskopisch äußerst charakteristisch für diese Strukturen ist in den IR‐Spektren die scharfe Bande der C ≡ N‐Valenzschwingung bei 2260 cm−1. Kennzeichnend in den Massenspektren ist die Abspaltung eines Cyanethylradikals. Während4antikonvulsive und cytoprotektive Effekte auszulösen vermag, ist5Träger neuroleptischer und herbizider Wirksamkeit.
Tetrahydrocyclopenta[e]pyrido[3,2‐b][1,4]diazepine and ‐cyclopenta[e]pyrido[2,3‐b][1,4]diazepine derivatives
Authors: Savelli Francesco , Boido Alessandro , Vazzana Iana , Sparatore Fabio 
Published: April 2009

AbstractIn pursuing the study on compounds obtained by condensation of N‐monoalkylated aromatic and hetero‐aromatic diamines with α‐ and β‐ketoesters, 7,8,9,10‐tetrahydrocyclopenta[e]pyrido[3,2‐b][1,4]diazepin‐6(5H)‐ones 4a, 4b and 5,7,8,10‐tetrahydrocyclopenta[e]pyrido[2,3,‐b][l,4]diazepin‐9H)‐ones 5a, 5b were prepared starting from 2,3‐diaminopyridine or 2,3‐diamino‐5‐chloropyridine and ethyl 2‐oxo‐cyclopentanecarboxylate. Compounds 4a,b and 5a,b suffer thermally induced ring contraction to the imidazolone derivatives 8a,b and 7a,b respectively and are unsuitable for preparing diazepinone derivatives. Thus the methylated diazepinones 15, 17 and 18, stable on heating, were prepared. Compound 17 was transformed into the clozapine analogue 22, through the diazepinthione 20 and its S‐methyl derivative 21.
Cyclocondensation of 3‐amino‐2‐iminonaphtho[1,2‐d]thiazole with oxalic acid derivatives
Authors: Liu Kang‐Chien , Shih Bi‐Jane , Hu Ming‐Kuan 
Published: April 2009

AbstractRefluxing 3‐amino‐2‐iminonaphtho[1,2‐d]thiazole (1) with diethyl oxalate (2a) in a 2:1 molar ratio in dry pyridine provided 2,2′‐binaphtho[1′,2′:4,5]thiazolo[3,2‐b][1,2,4]triazole (3). On the other hand, when 1 was treated with excess amount of 2a in dimethylformamide, it afforded ethyl naphtho[1′,2′:4,5]thiazolo[3,2‐b][1,2,4]triazole‐2‐carboxylate (4a) on heating and ethyl N‐(2‐iminonaphtho[1,2‐d]thiazol‐3‐yl)oxamate (5) by stirring at room temperature. Cyclization of 5 upon fusion led to the formation of 3‐hydroxy‐2H‐naphtho‐[1′,2′:4,5]thiazolo[3,2‐b][1,2,4]triazin‐2‐one (6). Compound 6 could also be prepared directly from 1 by refluxing either with 2a neatly, in glacial acetic acid or with oxalic acid (2b) in the same medium. The acid form of 4a might be obtained from 1 and 2b on heating in dimethylformamide, but it was decarboxylated to naphtho‐[1′,2′:4,5]thiazolo[3,2‐b][1,2,4]triazole (4b) during the reaction.
The preparation of quinolines and related fused‐ring heterocycles from the dianions of benzoylacetone, certain cyclic ketone oximes, or certain substituted hydrazones
Authors: Mack H. Michael , Davis Everette A. , Kadkhodayan Babak , Taylor Richard A. , Duncan Dean C. , Beam Charles F. 
Published: April 2009

AbstractC(α),O‐Dilithiooximes, C(α),N‐dilithiobenzoylhydrazones, or C(α),N‐dilithiocarboalkoxyhydrazones were prepared in an excess of lithium diisopropylamide (LDA) and condensed with 2‐aminobenzophenones, or isatoic anhydrides to give intermediates that were treated with aqueous acid, which caused their hydrolysis, cyclodehydration and/or linear dehydration to give products which were substituted quinolines or related fused‐ring heterocycles (e.g., cycloheptaquinolines). Dilithiobenzoylacetone was condensed with 2‐aminobenzophenones, which was followed by acid cyclodehydration to substituted 2‐phenacylquinolines.
The insertion and extrusion of heterosulfur bridges. XIV. Synthesis of nitrotriphenyleno[1,12‐bcd]thiophenes
Authors: Klemm L. H. , Hall Eliot , Cousins Lisa , Klopfenstein C. E. 
Published: April 2009

AbstractSulfur bridging to form triphenyleno[1,12‐bcd]thiophene (2) in ca. 46% yield has been effected at 540° by direct addition of crystalline triphenylene (1) or dodecahydrotriphenylene (4) to a heterogeneous catalyst in a stream of hydrogen sulfide. Treatment of a reaction mixture of 1 and 2 with hydrogen peroxide‐glacial acetic acid gives 2 sulfone 2d and 1,4‐triphenylenoquinone (3). Reduction of 2d with lithium aluminum hydride in tetrahydrofuran leads back to 2 (80%), while reductive acetylation of 3 produces 1,4‐diacetoxytriphenylene. Treatment of 2 with nitric acid in acetic anhydride at 65° gives a mixture of 1‐nitro (30%), 3‐nitro (47%), and 1,7‐dinitro (11%) derivatives, separable by chromatography on alumina. Structures of these derivatives are assigned on the basis of ultraviolet‐visible absorption and proton magnetic resonance spectra, as well as the chemical conversion 1‐nitro‐2 → 1,7‐dinitro‐2. The substitution pattern in 2 is correlated with Hückel molecular orbital calculations on reactivity and with substitution in analogous polycyclic, condensed aromatic compounds.
Studies on nitroenamines. Part III. Synthesis and spectral properties of 4‐Acyl‐1‐arylimidazoles
Authors: Gómez‐Sánchez A. , Hidalgo F. J. , Chiara J. L. 
Published: April 2009

AbstractThe catalytic (C/Pd) hydrogenation of 3‐arylamino‐2‐nitro‐2‐enones (1) in the presence of carboxylic ortho esters (2) affords 4‐acyl‐1‐arylimidazoles (3) in yields (20–70%) which depend on the degree of substitution of the imidazole ring. The spectral properties of compounds 3, and particularly the 13C‐nmr spectra, reflect both the electronic and steric effects of the substituents on the π‐electron delocalization and planarity of the bicyclic system.
A new method for the synthesis of novel 3‐substituted 4‐amino‐8‐ethoxycarbonylpyrazolo[5,1‐c][1,2,4]triazines and pyrazolo[1′,5′:3,4][1,2,4]triazino[5,6‐b][1,5]benzodiazepines
Authors: Kurasawa Yoshihisa , Okamoto Yoshihisa , Takada Atsushi 
Published: April 2009

AbstractNovel 3‐substituted 4‐amino‐8‐ethoxycarbonylpyrazolo[5,1‐c][1,2,4]triazines 7,8 were synthesized by the reactions of malononitrile and ethyl cyanoacetate with the pyrazole‐5‐diazonium salt 3. Moreover, compounds 7,8 were converted into the pyrazolo[1′,5′:3,4][1,2,4]triazino[5,6‐b][1,5]benzodiazepines 9, 10.