bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of 5‐aryl‐3‐carbazoyl‐1,3,4‐oxadiazol‐2(3H)‐one. Derivatives and their ring transformation into 5‐benzamido‐1,2,4‐triazolidine‐3,5‐dione derivatives
Authors: Milcent René , Barbier Géo , Tzirenstchikow Tatiana , Lebreton Luc
Published: March 2009

Some 5‐aryl‐3‐carbazoyl‐1,3,4‐oxadiazol‐2(3H)‐one derivatives 6 and 9 have been synthesized in two ways. The expected thermal ring transformation into 2,5‐disubstituted 1,3,4‐oxadiazoles did not occur but, by acid hydrolysis of 5‐aryl‐3‐[3‐benzylidene‐2‐methyl(or phenyl)carbazoyl]‐1,3,4‐oxadiazol‐2(3H)‐ones 6, a new ring transformation took place and the corresponding 4‐benzamido‐1‐methyl(or phenyl)‐1,2,4‐triazolidine‐3,5‐dione derivatives 11 were formed. The 4‐amino‐1‐phenyl‐1,2,4‐triazolidine‐3,5‐dione (19) has been prepared and its structure was confirmed by some reactions.
A novel synthesis of 5‐chloro‐3‐methoxycarbonyl‐1‐arylpyrazoles from arylazomethylenetriphenylphosphoranes
Authors: Baldoli C. , Lattuada L. , Licandro E. , Maiorana S. , Papagni A.
Published: March 2009

The reaction of arylazomethoxycarbonylmethylenetriphenylphosphoranes 1 with chloroform and sodium hydroxide in the presence of benzyltriethylammonium chloride (TEBA) as phase transfer catalyst directly affords 5‐chloro‐3‐methoxycarbonyl‐1‐arylpyrazoles 3.
Synthesis of novel methoxy and hydroxy derivatives of 2‐phenyl‐1H‐benz[g]indoles
Authors: Ferlin Maria Grazia , Chiarelotto Gianfranco , Malesani Giorgio
Published: March 2009

The synthesis of novel methoxy‐derivatives of 2‐phenyl‐1H‐benz[g]indole 3 by condensation of α‐naphthyl‐amines 1 with N‐phenacyl‐pyridinium salts 2 is described, as well as their conversion into the corresponding hydroxy‐derivatives 5. Unexpected quinoxaline derivatives 4 were obtained when in the condensation reaction the N‐nitrophenacylpyridinium salts 2d,e have been used.
Preparation of imidazo[2,1‐b]quinazolin‐5(3H)‐ones and related tricyclic systems using a novel, double displacement reaction
Authors: Peet Norton P. , Malecha James , Letourneau Michael E. , Sunder Shyam
Published: March 2009

New methodology is described for the construction of tricyclic heterocycles. Thus, a double displacement reaction of l‐(2‐fluorobenzoyl)‐2‐methylthio‐2‐imidazoline (8a) with 1,1‐dialkylhydrazines gave 10‐substituted 2,10‐dihydroimidazo[2,1‐b]quinazolin‐5(3H)‐ones in good yield. The corresponding 1‐(2‐nitrobenzoyl)‐2‐meth‐ylthio‐2‐imidazolines also underwent double displacement reactions with hydrazines. Other tricyclics made using double displacement reactions were pyrimido[2,1‐b]quinazolines, imidazo[1,2‐a]pyrido[2,3‐d]pyrimidines, and imidazo[1,2‐a]pyrazolo[3,4‐d]pyrimidines. Treatment of 8a with hydrazine hydrate or methylhydrazine gave products resulting from displacement, but did not afford fused benzotriazepinones.
Manganese dioxide oxidation of 3,4,4a,5‐tetrahydro[1,2,4]triazino[6,1‐c][1,4]benzoxazines
Authors: Bruché Luca , Zecchi Gaetano
Published: March 2009

Since we developed [1] a synthetic entry to 3,4,4a,5‐tetrahydro[1,2,4]triazino[6,1‐c][1,4]benzoxazines 1, we decided to explore the chemistry of this novel ring system. Its behaviour towards manganese dioxide is here described.
Preparation and reactions of isocyano‐1,3,5‐triazines
Authors: Hashida Yoji , Imai Akira , Sekiguchi Shizen
Published: March 2009

The title compounds 3 were prepared in low yields from the carbylamine reaction of amino‐1,3,5‐triazines 1 under phase‐transfer conditions. Isocyanotriazine 3a readily reacted with amines in the presence of copper salts to afford triazinylformamidines 4, and also with active methylene compounds in the presence of base to afford addition products 5 and 6, indicating the high electrophilicity of 3. The reactions of isocyanotriazine with electrophiles such as carbonyl compounds and bromine are also described.
Synthesis of certain substituted pyrimidines as potential schistosomicidal agents
Authors: El‐Kerdawy M. M. , El‐Emam A. A. , El‐Subbagh H. I. , Abushanab E.
Published: March 2009

A convenient route is reported for the synthesis of seven new pyrimidine derivatives namely: 2‐bromometh‐yl‐4,6‐dimethoxypyrimidine (3), 2‐dibromomethyl‐4,6‐dimethoxypyrimidine (4), 2‐acetoxymethyl‐4,6‐dimeth‐oxypyrimidine (5), 2‐hydroxymethyl‐4,6‐dimethoxypyrimidine (6), 4,6‐dimethoxypyrimidine‐2‐carboxaldehyde (7), 2‐acetoxymethyl‐6‐methoxy‐3,4‐dihydropyrimidin‐4‐one (8) and 2‐hydroxymethyl‐3,4‐dihydro‐6‐methoxy‐pyrimidin‐4‐one (9).
Methylfuroquinolinones: New furocoumarin isosters as potential photoreagents toward dna
Authors: Guiotto A. , Chilin A. , Pastorini G. , Palumbo M.
Published: March 2009

A number of methylfuro[3,2‐g]quinolin‐7(8H)‐ones, which can be considered isosters of methylpsoralens, were synthesized. The synthesis was performed starting from the appropriate methyl quinolin‐2‐ones on which the methylfuran ring was condensed. The molar absorptivity at long wavelengths of these compounds is remarkably higher than that of the corresponding methylpsoralen isosters; this fact may lead to an improved photo‐binding to the biological targets.
Synthesis and characterization of new quinoline monomers
Authors: Bottino F. A. , Di Pasquale G. , Pollicino A. , Recca A. , Staniland P. A.
Published: March 2009

New quinoline‐2,6‐dicarboxylic acid and 6‐aminoquinoline‐2‐carboxylic acid which are potential monomers for the introduction of quinoline units in commercial polymers such as polyamides, polyesters, etc. have been synthesized.
Synthesis of pyrazolo[3,4‐b][1,4]diazepines and pyrazolo[3,4‐b]pyrazines
Authors: Colombo Augusto , Frigola Jordi , Parés Juan , Andaluz Blas
Published: March 2009

The synthesis and structure elucidation of new pyrazolo[3,4‐b][1,4]diazepines and pyrazolo[3,4‐b]pyrazines are reported and the characterisation of isomers and tautomers by proton and carbon‐13 nmr are discussed. In some case only NOE experiments allow us to identify the isomeric structure.
Crystal structure of 1:1 Complexes between urea and two crown ether derivatives of phthalic acid, 2,3,5,6,8,9,11,12,14,15‐decahydrobenzo[1,4,7,10,13,16]hexaoxacyclo‐octadecin‐18,19‐dicarboxylic acid (i) and 2,3,5,6,8,9,11,12‐octahydro‐benzo[1,4,7,10,13]pentaoxacyclopentadecin‐15,16‐dicarboxylic acid (II)
Authors: Benetollo Franco , Bombieri Gabriella , Truter Mary R.
Published: March 2009

The crystal structures of the titlke compounds have been determined by X‐ray diffraction. Urea, I crystallizes in the triclinic PI space group with cell dimensions a = 8.336(2), b = 11.009(2), c = 13.313(2) Å, α = 105.55(3), β = 103.62(3), γ = 104.63(3)° and Z = 2 final R value 0.072 for 2105 observations. Urea, II crystallizes in the orthorhombic P212121 space group with cell dimensions a = 8.750(2), b = 10.844(3) and c = 21.215(3) Å and Z = 4, final R value 0.083 for 599 observations. All the hydrogen atoms were located in the complex urea, I; urea molecules form hydrogen bonded dimers about centers of symmetry, these dimers are sandwiched between macrocyclic rings forming one simple and one bifurcated hydrogen bond from the “endo” hydrogen atoms to the ether oxygen atoms. These units are held by hydrogen bonding between the urea molecules and carboxylic acids in two other units; these hydrogen bonds are cyclic involving eight atoms ‐(N‐H(exo)…O(keto)‐C‐O‐H…O(urea)‐C)‐. Only one carboxylic acid group per molecule takes part in these hydrogen bonds, the other forms a short, 2.490(7) Å, internal bond to the acceptor keto oxygen atom. N(H)…O bonds range from 2.930(7) to 3.206(7) Å, O(H)…O is 2.475(6) Å. In the complex urea, II each urea is hydrogen bonded to three different host molecules and vice versa; the urea “endo” hydrogen atoms bond to the ether oxygen atoms, while both “exo” hydrogen atoms take part in cyclic hydrogen bonds to carboxylic acids. There is not internal hydrogen bond. N(H)…O bonds range from 2.83 to 3.26(2) A and the O‐…O bonds are 2.55 and 2.56(2) Å.
The formation of 2,3‐disubstituted thiazolidin‐4‐ones from s‐α'‐aminomercaptoacetic acid derivatives
Authors: Tierney John
Published: March 2009

Variously substituted N‐benzylidineanilines rapidly react with thioglycolic acid to generate S‐α'‐aminomercaptoacetic acid derivatives. The latter subsequently cyclize to the corresponding 2,3‐diarylthiazolidin‐4‐ones. Kinetics for the first order cyclization reaction in the solvents toluene, carbon tetrachloride and nitrobenzene have been obtained over the temperature range 333 K to 383 K and are in accord with a neutral, but geometrically complex transition state.
Synthèse et étude de modèles de NADH à noyaux accolés en série pyrrolo[2,3‐b] et [3,2‐b]pyridines
Authors: Monnet Marie Odile , Fauret Thierry , Levacher Vincent , Dupas Georges , Bourguignon Jean , Quéguiner Guy
Published: March 2009

Des dérivés pyrrolo[2,3‐b] et [3,2‐b]pyridiniques précurseurs de modèles annelés du NADH ont été préparés. Plusieurs méthodes de construction d'un cycle pyridinique accolé ont été utilisées au départ de dérivés de l'amino‐2 ou −3 pyrrole. Le passage aux structures dihydropyridiniques correspondantes a permis d'obtenir des réactifs modèles du NADH possédant une excellente réactivité et beaucoup plus stables que les modèles habituellement utilisés.
Organic phosphorus compounds. Part 3. Synthesis of 5‐fluorosubstituted benzothiazolylbenzylphosphonates
Authors: Yoshino Kohichiro , Hori Noriyuki , Hori Manabu , Morita Tominori , Tsukamoto Goro
Published: March 2009

The regio specific synthesis of 5‐fluorobenzothiazoles 14 has been accomplished by using difluorothiobenzanilides 13 as a key intermediate. Through this method, 5‐fluorosubstituted fostedil 3 and its derivatives were synthesized and evaluated coronary vasodilator activity.
A new synthesis of pyrazolo[1,5‐d][1,2,4]triazines from pyrazolecarboxylic acid hydrazides and carbonyl compounds. I
Authors: Tihanyi E. , Gál M. , Fehér Ö. , Dvortsák P.
Published: March 2009

Pyrazolo[1,5‐d][1,2,4]triazines were synthesized from pyrazolecarboxylic acid hydrazides and carbonyl compounds. Pyrazolecarboxylic acid N‐phenylhydrazide (1c) and formaldehyde gave not only the expected 4hn but 5, respectively. The methyl substituted hydrazides with acetone afforded hydrazones, pyrazolotriazines or 13 depending on the position of the substituents. The reduction of both products yielded pyrazolecarboxylic acid hydrazides.
Reaction of N‐hydroxymethylsaccharin with aliphatic carboxylic acid derivatives: Synthesis of N‐acylsaccharins and N‐(saccharinylmethyl) aliphatic carboxylates
Authors: Choi Sam‐Young , Lee Sang‐Gyeong , Yoon Yong‐Jin , Kim Kyu‐Wan
Published: March 2009

N‐Acylsaccharins and N‐(saccharinylmethyl)aliphatic carboxylates were synthesized from N‐hydroxymeth‐ylsaccarin and aliphatic carboxylic acid chlorides (or anhydrides).
Oxidation of 2‐amino‐4‐methylphenol in acidic medium
Authors: Bolognese Adele , Liberatore Rosa , Schäfer Wolfram
Published: March 2009

The oxidation of 2‐amino‐4‐methylphenol 1, by ferricyanide, in acetic acid yields benzoquinonimine 2, phenoxazinonimine 3 and 4, triphenodioxazines 5 and phenoxazinone 6. The reaction mechanism seems to start with an electrophilic substitution of the quinonimine, from 1, on the electron rich 1, rather than with a nucleophilic attack of 1 on the arising quinonimine.
Dérivés de l'imidazo[2,l‐b]thiazole. IX. Comportement du phénacyl‐3 dihydro‐5,6 imidazo[2,1‐b]thiazole et du phénacylidène‐3 tétrahydro‐2,3,5,6 imidazo[2,1‐b]thiazole vis‐à‐vis du chlorhydrate d'hydroxylamine
Authors: Hablouj Mustapha , Robert Jean‐François , Vebrel Joël
Published: March 2009

L'action du chlorhydrate d'hydroxylamine sur deux imidazothiazoles possédant un carbonyle cétonique conduit à deux types de composés selon la quantité d'acétate de sodium mise en oeuvre. Un halohydrate de phénacyl‐3 dihydro‐5,6 imidazo[2,1‐b]thiazole donne logiquement naissance à l'oxime correspondante, isolée sous forme de sel ou de base selon la quantité d'ions acétates introduite. De plus, il se produit systématiquement un réarrangement allylique par migration de la double liaison du cycle thiazole en une position juxtanucléaire. Le phénacylidène‐3 tétrahydro‐2,3,5,6 imidazo[2,1‐b]thiazole, en l'absence d'acétate de sodium, donne directement le sel de l'oxime réarrangée. Par centre, en présence d'acétate de sodium, on isole une hydroxylamine, caractérisée par le retour de la double liaison en 2,3 du cycle thiazole. II est remarquable qu'il n'ait pas été possible de transformer cette hydroxylamine en oxime et vice‐versa quelle que soil la nature du milieu réactionnel (acide ou basique). Ces différents composés ne présentent pas d'activité fongistatique contrairement aux cétones dont ils sont issus.
Cycloaddition dipolaire‐1,3 des arylnitriloxydes sur les dihydro‐1,2 quinoleines n‐substituees
Authors: Soufiaoui M. , Jazouli H.
Published: March 2009

La réaction de cycloaddition dipolaire‐1,3 des arylnitriloxydes sur la dihydro‐1,2 quinoléine donne deux adduits si l'atome d'azote du dipolarophile porte un groupement benzoyle. Par contre la réaction ne fournit qu'un seul adduit si le groupement est un benzyle. La structure des cycloadduits a été établie par voies spectroscopique et chimique.

The 1.3‐depolar cycloaddition reacton of arylnitrile oxides on 1,2‐dihydroquinolines gives two adducts if the nitrogen atom of the dipolarphile carries a benzoyl group. The structure of the cycloadducts has been established by spectoscopic and chemical methods.
Novel dyestuffs containing dicyanomethylidene groups
Authors: Katritzky Alan R. , Fan Wei‐Qiang , Liang De‐Sheng , Li Qiao‐Ling
Published: March 2009

Several series of novel compounds have been prepared containing dicyanomethylidene groups including 1‐alkyl‐3‐dicyanomethylideneindol‐2‐ones and 6,6‐dicyanofulvenes. Their visible absorption properties are recorded and discussed.
Reinvestigation of a 5H‐dibenzo[d,h][1,3,6]triazonine synthesis
Authors: Peet Norton P. , Sunder Shyam , Barbuch Robert J. , Whalon Michael R. , Huber Edward W. , Huffman John C.
Published: March 2009

Treatment of 5‐chloro‐2‐aminobenzophenone (1) witho‐phenylenediamine, sodium acetate, and acetic acid gave 2‐(acetyl)amino‐5‐chlorobenzophenone (5) rather thanN‐[(2‐amino‐5‐chlorophenyl)phenylmethylene]‐1,2‐benzenediamine (3), as reported by Kulkarniet al, [1]. Authentic3was prepared and treated with chloroacetic acid and polyphosphoric acid (PPA) to give1, recovered3, 2,8‐dichloro‐6,12‐diphenyldibenzo[b,f][1,5]diazocine (9) and 2‐chloro‐6‐(chloromethyl)‐13‐phenyl‐5H‐dibenzo[d,h][1,3,6]triazonine (10). Treatment of5with PPA, with or without chloroacetic acid, gave [5‐chloro‐2‐[(6‐chloro‐4‐phenyl‐2‐quinolinyl)amino]phenyl]phenylmethanone (11) as the sole product in 90% yield. Treatment of other benzophenones, acetophenones, and anilines with sodium acetate and acetic acid provided acetanilides in 78‐96% yield, with the exception of 2′‐aminoacetophenone (20), which gave a quantitative yield of 2‐[((2‐acetyl)phenyl)amino]‐4‐methylquinoline (21). The mechanism of acetanilide formation with sodium acetate and acetic acid is discussed. The structure of21was established using high resolution1H nmr techniques. Attempts to prepare an authentic sample of21from 2‐chlorolepidine (26) and (20) gave 4‐methyl‐N‐[2‐(4‐methyl‐2‐quinolinyl)phenyl]‐2‐quinolinamine (29) as the major product.
Cycloaddition reactions of 2,3‐dihydro‐1H‐1,4‐diazepines with nitrile oxides and imines. Synthesis of bis[1,2,4]oxadiazolo‐and bis[1,2,4]triazolo[1,4]diazepine derivatives
Authors: Aversa Maria C. , Bonaccorsi Paola , Giannetto Placido , Leigh David A.
Published: March 2009

New heterotricyclic systems, 6,10a,11,11a‐tetrahydro‐5H‐bis[1,2,4]oxadiazolo[4,5‐d:5′,4′‐g][1,4]diazepines 6,7,9‐11 and 5,6,10,10a,11,11a‐hexahydro‐1H‐bis[1,2,4]triazolo[4,3‐d:3′,4′‐g][1,4]diazepines 8,12 have been obtained by double site‐ and regie‐specific 1,3‐dipolar cycloaddition of mesitylnitrile oxide (1) or diphenylnitrile imine (2) to 5,7‐disubstituted 2,3‐dihydro‐1H‐1,4‐diazepines 3‐5. The structure of the synthesized bis‐adducts 6‐12 shows that the hetero double bonds are much more reactive than the olefinic ones in the dipolarophiles under study. No evidence for the formation of mono‐adducts was obtained.
New quinoxaline and pyrimido[4,5‐b]quinoxaline derivatives. Potential antihypertensive and blood platelet antiaggregating agents
Authors: Monge A. , Palop J. A. , Urbasos I. , Fernández‐Alvarez E.
Published: March 2009

Starting with 3‐amino‐2‐quinoxalinecarbonitrile 1,4‐dioxide 1, a new series of quinoxaline derivatives 2‐12 was synthetized through chemical modification of the 3‐amino group, the 2‐cyano group and selective mono‐deoxygenation of the 1‐oxide or 4‐oxide groups. On the other hand, two 2,4‐diaminopyrimido[4,5‐b]quinoxa‐line derivatives 13, 14 were obtained condensing 3‐amino‐2‐quinoxaline carbonitriles with quanidine. Some of the new compounds were studied as inhibitors of blood platelet aggregation as well as antihypertensive agents.
3′‐(1,2,3‐Triazol‐1‐yl)‐2′,3′‐dideoxythymidine and 3′‐(1,2,3‐triazol‐1‐yl)‐2′,3′‐dideoxyuridine
Authors: Wigerinck Piet , Van Aerschot Arthur , Claes Paul , Balzarini Jan , De Clercq Erik , Herdewijn Piet
Published: March 2009

Cycloaddition of different acetylenic compounds on the azido function of 3′‐azido‐2′,3′‐dideoxythymidine and 3′‐azido‐2′,3′‐dideoxyuridine afforded products with a 1,2,3‐triazol‐1‐yl substituent in the 3′‐position. In contrast with the parent compounds, these triazolyl derivatives had no appreciable activity against human immunodeficiency virus (HIV‐1).
Alkylation of tetraazapentalene derivatives having a hypervalent sulfur or selenium using alkyl iodide
Authors: Matsumura Noboru , Tomura Masaaki , Inoue Hiroo
Published: March 2009

Alkylation of 2,3,4a,7a‐tetraazapentalene derivatives having a hypervalent sulfur or selenium using alkyl iodide in benzene under reflux afforded the S‐monoalkylated tetraazapentalene derivatives 3 and 4 in good yields.
The cycloaddition of heterocumulenes to oxetanes in the presence of catalytic amounts of tetraphenylstibonium iodide
Authors: Fujiwara Masahiro , Baba Akio , Matsuda Haruo
Published: March 2009

The cycloadditions of carbon dioxide, isocyanates and carbodiimides to oxetanes proceeded in the presence of catalytic amounts of tetraphenylstibonium iodide (1) under mild conditions, affording the corresponding six‐membered heterocycles; 1,3‐dioxan‐2‐ones, 1,3‐oxazin‐2‐ones and 1,3‐oxazin‐2‐imines in good yields, respectively. Moreover, the cycloaddition of 2‐phenyloxetane proceeded via predominant ring‐cleavage at substituted site.
New heterocyclic structures. [1,3]Thiazino[3,2‐a]purine and [1,2,3]triazolo[4,5‐d][1,3]thiazino[3,2‐a]pyrimidine
Authors: Pecorari Piergiorgio , Rinaldi Marcella , Costi Maria Paola
Published: March 2009

Derivatives of two new molecular structures, namely, [1,3]thiazino[3,2‐a]purine and [1,2,3]triazolo[4,5‐d]‐[1,3]thiazino[3,2‐a]pyrimidine, were synthesized together with other heterocyclic compounds. Retrosynthetic analysis of their molecular skeletons suggested a simple way of obtaining 3,4‐dihydro‐7,8‐diamino‐2H,6H‐pyrimido[2,1‐b][1,3]thiazin‐6‐one, which is a useful intermediate for their synthesis. This intermediate and the thiazole homologue were obtained directly by reaction of 5,6‐diamino‐2,3‐dihydro‐2‐thioxo‐4(lH)‐pyrimidi‐none with 1,3‐ or 1,2‐dibromoalkane, respectively.
Acid‐catalyzed reactions of 3‐(hydroxymethyl)‐ and 3‐(1‐hydroxyethyl)pyrazolo[1,5‐a]pyridines
Authors: Miki Yasuyoshi , Nakamura Noriko , Hachiken Hiroko , Takemura Shoji
Published: March 2009

Treatment of 3‐(hydroxymethyl)pyrazolo[1,5‐a]pyridines with trifluoroacetic acid in refluxing dichloro‐methane led to the formation of bis(pyrazolo[1,5‐a]pyrid‐3‐yl)methanes or bis[(pyrazolo[1,5‐a]pyrid‐3‐yl)]‐methyl ethers depending upon the concentration of trifluoroacetic acid. In contrast, similar treatment of 3‐(1‐hydroxyethyl)pyrazolo[1,5‐a]pyridines gave a mixture of 3‐vinylpyrazolo[1,5‐a]pyridines and 1,3‐bis(pyrazolo‐[1,5‐a]pyrid‐3‐yl)‐1‐butenes.
Synthesis of bridged heteroaromatic compounds as reference standards for coal degradation products
Authors: Luo Jiann‐Kuan , Takahashi Kazufumi , Mckenney J. Dew , Castle Raymond N. , Lee Milton L.
Published: March 2009

The synthesis of 2‐naphthyl 2′‐dibenzothienyl ether, 1‐(1′‐naphthyl)‐2‐(4″‐acridinyl)ethane and a series of naphthylethyldibenzothiophenes is reported.
Studies on the chemistry of 5‐propynyloxy‐ and 5‐propynylthiopyrimidines: New syntheses of furo‐ and thieno[3,2‐d]pyrimidines
Authors: Spada Marianne R. , Klein Robert S. , Otter Brian A.
Published: March 2009

The utility of certain 5‐alkynyloxy‐, 5‐alkynylthio, and 5‐alkynylsulfinyl‐pyrimidines as precursors of 7‐substituted furo[3,2‐d]‐ and thieno[3,2‐d]pyrimidines has been examined. When treated with sodium methoxide in warm methyl sulfoxide, 1,3‐dimethyl‐5‐(2‐propynyloxy)uracil (6) cyclizes to afford 1,3,7‐tri‐methylfuro[3,2‐d]pyrimidine‐2,4‐(1H,3H)‐dione (12) in 52% yield, possibly via the allenic ether 9 (R = H). The corresponding 5‐(2‐butynyloxy)pyrimidine (7), obtained in good yield by treating 6 with methyl iodide and sodium hydride in methyl sulfoxide, fails to undergo an analogous cyclization. However, compound 7 does undergo a normal alkynyl Claisen rearrangement and cyclization when heated at 130°, giving the 8‐methylpyrano[3,2‐d]pyrimidine 8 in methyl sulfoxide and the 6,7‐dimethylfuro[3,2‐d]pyrimidme 11 in dimethylformamide. The 5‐(2‐propynylthio)pyrimidine 15 affords the allene 19 and the 1‐propyne 22 when treated with various bases, but none of the 7‐methylthieno[3,2‐d]pyrimidine 16. At 145° in methyl sulfoxide, 15 undergoes a thio‐Claisen rearrangement process to afford the 6‐methylthieno[3,2‐d]pyrimidine 17 together with substantial amounts of a product 20 that bears a 7‐thiomethoxymethyl substituent derived from the solvent. Heating the 5‐(2‐propynylsulfinyl)pyriniidine 23 at 105° in methyl sulfoxide, followed by acidification of the reaction mixture, affords 1,3‐dimethyl‐7‐formylthieno[3,2‐d]pyrimidine‐2,4‐(1H,3H)‐dione (29) in 47% yield. Deuterium labelling studies established that the aldehyde proton of 29 is derived from the 3′‐proton of 23. This finding is consistent with a mechanism that involves sequential [2,3] and [3,3] sigma‐tropic rearrangements, and the intermediacy of a dihydrothieno[3,2‐d]pyrimidine such as compound 30.
Synthesis of vinca alkaloids and related compounds.XLVI.. Formation of a new ring system
Authors: Dancsó András , Kajtár‐Peredy Mária , Szántay Csaba
Published: March 2009

In the Pictet‐Spengler reaction of indole‐3‐propanamine1and diethyl‐(2‐formyl‐cyclopropane‐1,1‐dicar‐boxylate)2the formation of ethyl (1a,2,4,5,6,11,11b,11c‐octahydro‐2‐oxo‐1H‐cycloprop[3′,4′]pyrrolo[1,2′:1,2]‐azepino[3,4‐b]indole‐1a‐carboxylates)3and4was observed. Compounds3and4represent a new ring system.
Oxidation of heterocyclic nitrogen ylids to nitro heterocycles. Comparison of dimethyldioxirane with peracids
Authors: Coburn Michael D.
Published: March 2009

Oxidation of 3‐amino‐4‐(4‐chlorophenyl)furazan (1) and its phosphine imine derivative, 3‐(4‐chlorophenyl)‐4‐trioctylphosphiniminofurazan (3), with dimethyldioxirane (DMD) gave 3‐(4‐chlorophenyl)‐4‐nitrofurazan (4) as the exclusive product. However, the sulfilimine derivative, 3‐(4‐chlorophenyl)‐4‐dimethylsulfiliminofurazan (2), was converted by DMD to the sulfoximine, 3‐(4‐chlorophenyl)‐4‐dimethylsulfoximinofurazan (6). These results contrast dramatically with the oxidations of these compounds with peracids.
Formation of oxadiazolo[4,5‐a]indolines via addition reactions of cycloalkano[b]indoles with nitrile oxides. Crystal structure of an adduct
Authors: Coutouli‐Argyropoulou E. , Malamidou‐Xenikaki E. , Mentzafos D. , Terzis A.
Published: March 2009

Reactions of stable nitrile oxides with cycloalkano[b]indoles gave as main product adducts 3 containing the oxadiazolo[4,5‐a]indoline ring system. The structure elucidation of the isolated adducts was based on their spectral data, chemical behaviour and in one case the structure was confirmed by crystallographic X‐ray analysis. The mechanism of the reaction is also discussed.
Synthesis of quinoline derivatives using ketene dithioacetals
Authors: Tominaga Yoshinori , Michioka Takeharu , Moriyama Kohu , Hosomi Akira
Published: March 2009

Methyl 3‐(N‐arylamino)‐2‐cyano‐3‐methylthioacrylates 3a‐h, which are readily prepared by the reaction of the ketene dithioacetal, methyl 2‐cyano‐3,3‐bis(methylthio)acrylate (1) with arylamines, was heated at reflux in diphenyl ether to give the corresponding 2‐methylthio‐4‐hydroxyquinoline‐3‐carbonitriles 4a‐h in 14–77% yields. The reaction of 1 with excess aryl amines in diphenyl ether at reflux gave also the corresponding 2‐arylamino‐4‐hydroxyquinoline‐3‐carbonitriles 6a‐d. The 2‐methylthioquinoline‐3‐carbonitriles 4a‐h, thus obtained, are useful intermediates for the synthesis of various quinoline derivatives.
Synthesis of large macrocyclic tetraaza compounds with a methylene backbone: Cyclo[‐NH‐ (CH2)n‐]4, (n = 6, 7, 8, 9 and 10). The formation of 28‐, 32‐, 36‐, 40‐ and 44‐membered rings
Authors: Tomohiro Takenori , Uoto Kouichi , Okuno Hiroaki (Yohmei)
Published: March 2009

A series of macrocyclic tetraamines with 28‐, 32‐, 36‐, 40‐ and 44‐membered rings have been efficiently prepared from the corresponding ditosylamide and monobromoalcohol derivatives in 6 steps via a double condensation reaction. Overall yields were: 41, 41, 46, 29, and 33%, respectively, for 1,8,15,22‐tetraazacyclooctacontane (11a), 1,9,17,25‐tetraazacyclodotriacontane (11b), 1,10,19,28‐tetraazacyclohexatriacontane (11c), 1,11,21,31‐tetraazacyclotetracontane (11d) and 1,12,23,34‐tetraazacyclotetratetracontane (11e).
Synthesis of 3‐aminopyrazolo[3,4‐d]pyrimidine derivatives using N‐bis(methylthio)methylene‐p‐toluenesulfonamide
Authors: Tominaga Yoshinori , Hara Mayumi , Honkawa Harumasa , Hosomi Akira
Published: March 2009

N‐Bis(methylthio)methylene‐p‐toluenesulfonamide (1) reacted with active methylene compounds such as malononitrile (2a) and, cyanoacetamide (2b) to give the corresponding 3‐methylthio‐3‐p‐toluenesulfonylami‐nopropenenitrile derivatives 3a,b which were found to be convenient starting materials for the synthesis of 3,5‐diaminopyrazole derivatives. Reaction of 3a and 3b with hydrazines gave the corresponding 3,5‐diaminopyrazoles 4a‐e, key intermediates for the synthesis of 3‐aminopyrazolo[3,4‐d]pyrimidine derivatives 5a‐d.
On triazoles. XXI. Synthesis of 1,2,4‐triazolyldithiocarbonates
Authors: Pongó László , Reiter József , Barkóczy József , Sohár Pál , Pallagi István
Published: March 2009

The reaction of 5‐amino‐1,2,4‐triazoles 1 with carbon disulfide and alkylating agents in basic condition to yield alkyl, aralkyl and aryl (5‐amino‐3‐Q‐1,2,4‐triazol‐1‐yl)dithiocarbonates 2 and alkyl (3‐Q‐1,2,4‐triazol‐5‐yl‐amino)dithiocarbonates 3 was studied. The isomeric and tautomeric structure of derivatives obtained was proved with the help of their uv, pmr and cmr spectra using model compounds prepared for this purpose. The results obtained enabled us to correct some confusion in the literature.
Diheterocyclic compounds from dithiocarbamates and derivatives thereof. IV. 3,3′‐arylenebis‐(4‐oxo‐2‐thioxo‐1,2,3,4‐tetrahydroquinazolines)
Authors: Garín Javier , Meléndez Enrique , Merchán Francisco L. , Merino Pedro , Orduna Jesús , Tejero Tomás
Published: March 2009

The title compounds 3 were synthesized in one step from bisdithiocarbamates 2, and their structures were confirmed by two independent syntheses. Alkylation and hydrolysis of 3 gives 3,3′‐arylenebis(2,4‐dioxo‐1,2,3,4‐tetrahydroquinazolines) 8.
Réactivité des esters de la carboxyméthylène‐1 hydroxy‐4 méthyl‐6 pyridone‐2 vis‐à‐vis des aldéhydes aromatiques
Authors: Kherfi Houria‐Nacera , Hamdi Maâmar , Spéziale Vincent
Published: March 2009

Une nouvelle réaction de condensation d'aldéhydes aromatiques sur des pyridones‐2 a été examinée. La carboxyméthylène‐1 hydroxy‐4 méthyl‐6 pyridone‐2 1 et les esters méthylique et éthylique correspondants 2 et 3 ont permis de synthétiser des arylméthanes par réaction entre une molécule d'aldéhyde et deux molécules de pyridone. l'étude spectroscopique des dérivés obtenus a été réalisée et un mécanisme réactionnel pour leur formation a été proposé.
Synthesis of 1,2,3‐thiadiazole‐5‐carbaldehydes and their conversion into 6aδ4‐Thia‐1,2,5,6‐tetraazapentalenes
Authors: L'Abbé Gerrit , Frederix Ann
Published: March 2009

A convenient method for the synthesis of the virtually unknown 1,2,3‐thiadiazole‐5‐carbaldehydes consists in monobromination of the 5‐methyl derivatives, followed by treatment with sodium azide and decomposition in concentrated sulfuric acid (6 → 7 → 9 → 10). These compounds can be transformed via methylation of the corresponding hydrazones 12 into 6aδ4‐thia‐1,2,5,6‐tetraazapentalenes 13.
Palladium‐catalyzed synthesis of isocoumarin and 1‐isoquinolinone derivatives
Authors: Izumi Taeko , Nishimoto Yasuhiro , Kohei Kunihiro , Kasahara Akira
Published: March 2009

In the presence of copper(I) chloride, the palladium catalyzed oxidation of methyl 2‐ethenylbenzoates and 2‐ethenylbenzamides have been studied. This reaction was used to form isocoumarins and 1‐isoquinolinones.
Reaction of electron rich heterocycles with electrophiles. Formylation of indoles via thiomethylation
Authors: Akgün Eyup , Tunali Mustafa
Published: March 2009

The formylation of indoles 1 by dithiocarbenium‐ions 2 is discussed. The reaction proceeds to thioacetals 4 under mild conditions. Longer reaction times yield bisindolylmonomethylcyanines 5–6. Generally, the reaction is inhibited by the presence of electron‐withdrawing groups at the pyrrol nucleus of indole 1, e.g. an acetyl group.
2H‐1,2,4‐benzothiadiazine 1,1‐dioxides 2. A condensation of 2‐aminobenzenesulfonamide with chloroalkyl isothiocyanates
Authors: Chern Ji‐Wang , Wu Ying‐Hwa , Liu Kang‐Chien
Published: March 2009

A reaction of 2‐aminobenzenesulfonamide (1) with 2‐chloroethyl or 3‐chloropropyl isothiocyanate in isopropanol afforded 2‐(2′‐chloroethylthioureido)‐ and 2‐(3′‐chloropropylthioureido)benzenesulfonamides (2a,b) in 67% and 55% yield respectively. Treatment of 2a,b with triethylamine in methanol at room temperature furnished 3‐(2′‐aminoethylthio)‐ and 3‐(3′‐aminopropylthio)‐2H‐1,2,4‐benzothiadiazine 1,1‐dioxides (9a,b) in quantitative yield. Heating 2b to reflux in methanol under neutral conditions gave 9b but in the form of the hydrochloride 8b which could be converted into the free base 9b by treating with ammonia water. When compounds 2a,b were treated with triethylamine in methanol at elevated temperature, 3‐(2′‐mercaptoethylamino)‐ and 3‐(3′‐mercaptopropylamino)‐2H‐1,2,4‐benzothiadiazine 1,1‐dioxides (10a,b) were obtained in good yield. Alternatively, 10a,b could also be prepared from 9a,b in 95% and 77% yield respectively.
Non‐steroidal antiinflammatory agents. VI. Synthesis of 10‐oxo‐5H‐pyrrolo[1,2‐b]isoquinoline‐3‐acetic Acid, a conformationally restricted analogue of tolmetin
Authors: Corelli Federico , Garofalo Antonio , Massa Silvio , Silvestri Romano , Prosini Pierpaolo , Artico Marino
Published: March 2009

The synthesis of 10‐oxo‐5H‐pyrrolo[1,2‐b]isoquinoline‐3‐acetic acid 4, a tricyclic analogue of tolmetin which might show significant analgesic‐antiinflammatory activity, has been accomplished in four steps. Alkylation of ethyl 2‐pyrrolylglyoxylate (15) with 2‐cyanobenzyl bromide afforded derivative 16, which was transformed by the Huang‐Minion reaction into the dicarboxylic acid 6. Cyclization of this key intermediate to 17, followed by alkaline hydrolysis, afforded 10‐oxo‐5H‐pyrrolo[1,2–6]isoquinoline‐3‐acetic acid (4). Various attempted syntheses of 6 are also discussed.
Some reactions of thieno‐fused quinoline N‐oxides
Authors: Gronowitz Salo , Timari Géza
Published: March 2009

A convenient method for the conversion of the three thieno‐fused quinoline N‐oxides to the corresponding 4‐oxo‐4,5‐dihydrothienoquinolines is described. They have been alkylated with dimethylaminoethyl and dimethylaminopropyl chlorides. The reaction of the three thieno‐fused quinolines with dimethyl acetylenedicarboxylate has been studied, as well as their reactions with butyllithium and LDA.
Synthesis and antibacterial activity of 2,3‐dehydroofloxacin
Authors: Augeri David J. , Fray Andrew H. , Kleinman Edward F.
Published: March 2009

The 2,3‐dehydro analog 2 of the potent quinolone antibacterial agent ofloxacin (1) was synthesized by an efficient six step route beginning with ethyl 2,3,4,5‐tetrafluorobenzoylacetate. Formation of the oxazine ring of 2 was accomplished by ozonolysis of 1‐(1‐buten‐3‐yl)quinolone 5 to the corresponding aldehyde, which cyclized upon treatment with base via intramolecular displacement of the C‐8 fluorine to afford tricyclic ester 6. The antibacterial activities of 2,3‐dehydroofloxacin (2) and ofloxacin (1) are compared.
Synthesis of 3‐amino‐5H‐1,2,3‐triazino[5,4‐b]indol‐4‐one. New compounds with blood platelet antiaggregation activity
Authors: Monge A. , Aldana I. , Arrarás J. A. , Fernández‐Alvarez E.
Published: March 2009

Starting with 3‐aminoindole‐2‐carbohydrazide 1 a series of arylidene hydrazones 2 was obtained with good yields (79–85%). Upon treating 2 with nitrous acid a series of 3‐arylidineamino‐5H‐1,2,3‐triazino[5,4‐b]indol‐4‐ones 3 was obtained (80–86%). The reaction of 4‐methoxybenzylidene derivative 3e with hydrazine hydrate, in ethanol, gave 3‐amino‐5H‐1,2,3‐triazino[5,4‐b]indol‐4‐one 4 (64%). However, by treating 3e in boiling hydrate, 3‐aminoindole‐2‐carbaldehyde azine 5 was obtained (44%). By boiling 1 in N,N‐dimethylformamide, 3‐amino‐5H‐pyrimido[5,4‐b]indol‐4‐one, 6 was obtained (52%).
Isolation of 1,2,3,4‐tetrahydrobenzo[f]quinolin‐2‐ones on the reaction of 2‐arylidenenaphthylamines with 4‐hydroxycoumarin. IV
Authors: Martínez Roberto , Cortés Eduardo , Toscano Rubén A. , Alfaro L. Josué , Avila J. Gustavo
Published: March 2009

The reaction of 2‐arylidenenaphtylamines with 4‐hydroxycoumarin results in Hoffman‐Martius type rearrangement yielding 2H‐benzo[f][1]benzopyrano[4,3‐b]quinolin‐2‐ones I and the compounds II. This work describes the structure elucidation of the compounds II. The structure was confirmed using ir, nmr and X‐ray spectroscopy.
Synthesis and spectroscopic characterization of 1‐[1,2,3‐triazol‐1‐yl]‐4‐aroylazetidin‐2‐ones
Authors: Bojilova Anka , Rodios Nestor A.
Published: March 2009

1‐(N‐Phenacylidene)amino‐1,2,3‐triazoles 3 react with propionylchloride and phenoxyacetylchloride in the presence of triethylamine to give trans‐ (5) and cis‐ (6) 1‐(1,2,3‐triazol‐1‐yl)‐4‐aroylaztidin‐2‐ones in a 1:1 ratio, on the contrary to the 1‐(N‐arylidene)amino‐1,2,3‐triazoles, which do not give any reaction product with the same acid chlorides. The spectroscopic characteristics of these new N‐triazolyl‐β‐lactams are also discussed.
1,3‐Dipolar cycloadditions of nitrile oxides with 4‐carbethoxymethyleno‐4,5,6,7‐tetrahydro‐6,6‐dimethylbenzo[c][1,2,5]oxadiazole
Authors: Koumbis Alexandros E. , Stephanidou‐Stephanatou Julia , Alexandrou Nicholas E.
Published: March 2009

The (E)‐ and (Z)‐α,β‐unsaturated esters, 3 and 4 are prepared by applying a Wittig reaction on the ketone 1. Stable nitrile oxides are added to the stable (E)‐isomer 3 resulting to the formation of the spiro‐derivatives 7, whereas with the unstable nitrile oxides a second stereoisomer 8 is also formed. Mesitonitrile oxide reacts also with the ketone 1 to give the spiro‐cycloadduct 10. The assignment of regio‐isomers 7 was deduced from their spectral data as well as from some molecular orbital considerations.
Quinolone antibacterials. 2. 6‐Substituted‐7‐(2‐thiazolyl and thiazolidinyl)quinolones
Authors: Zhang M. Q. , Haemers A. , Vanden Berghe D. , Pattyn S. R. , Bollaert W. , Levshin I.
Published: March 2009

A series of 6‐substituted‐1‐ethyl‐1,4‐dihydro‐4‐oxo‐7‐(2‐thiazolyl‐ and thiazolidinyl)quinoline‐3‐carboxylic acids were synthesized. Substitution at the 6‐position was H, F or Cl. The Hantzsch method was used for the preparation of the thiazolylquinolones. The thiazolidinylquinolones were synthesized by quaternization of the corresponding thiazolyl analogues, followed by reduction of the obtained thiazolium salts with sodium borohydride in aqueous solution. Antibacterial activity was tested in vitro. The compounds were inactive against Gram‐negative bacteria but some of them showed good activity against Gram‐positive bacteria and mycobacteria. This activity pattern is rarely found among the quinolone antibacterials.
Products from Furans. XVI. Novel synthetic routes to sympathomimetic amine analogues via 6‐hydroxy‐2H‐pyran‐3(6H)‐ones
Authors: Georgiadis Minas P. , Haroutounian Serkos A. , Couladouros Elias A. , Apostolopoulos Costas D. , Chondros Kostas P.
Published: March 2009

Novel heterocyclic analogues mimicking compounds with antipsychotic activity (sympathomimetic amines) were synthesized. These compounds contain the phenyl‐substituted pyran ring system as a consequence of their common route of preparation. Furthermore an example of the synthetic route for preparing compounds having the features of both β‐hydroxy‐β‐phenylethylamine and GABA is also presented.
Synthesis and reactions of 3‐carboxytropolone. Conversion to heterocycle‐fused troponoid compounds
Authors: Zhang Luo‐Cheng , Imafuku Kimiaki
Published: March 2009

The haloform reaction of 3‐acetyltropolone (1) afforded 3‐carboxytropolone (2) which was treated with diazomethane to give 2‐methoxy‐3‐methoxycarbonyltropone (3a) and 2‐methoxy‐7‐methoxycarbonyltropone (3b). The tropolone 2 reacted with hydrazine to afford 2‐hydrazino‐3‐hydrazinocarbonyltropone (10) or 2‐hydrazinotropone (11), depending on the reaction time. The reaction of 2 with phenylhydrazine produced 3‐hydroxy‐1‐phenyl‐1,8‐dihydrocycloheptapyrazol‐8‐one (14). The treatment of 2‐methoxy‐3‐methoxycarbonyltropone (3a) with hydrazine or phenylhydrazine gave cyclization products 12 and 15, respectively. The reaction of 2‐methoxy‐7‐methoxycarbonyltropone (3b) with hydrazine, phenylhydrazine, or methylhydrazine gave 2‐hydrazino‐ (13), 2‐(2‐phenylhydrazino)‐ (16), and 2‐(2‐methylhydrazino)‐7‐methoxycarbonyltropone (17), respectively.
Two‐dimensional NMR studies of 2‐substituted thioxanthene sulfoxides
Authors: Mlotkowska B. L. , Cushman James A. , Harwood J. , Lam W. W. , Ternay A. L.
Published: March 2009

2‐Fluoro‐, 2‐chloro‐, 2‐bromo‐, 2‐methyl‐, and 2‐methoxythioxanthene have been prepared by borane reduction of the corresponding thioxanthone. The corresponding sulfoxides were prepared by m‐chloroperoxybenzoic acid oxidation of these sulfides. Proton and carbon chemical shifts have been assigned to these thioxanthene sulfoxides with the aid of LROCSCM and SROCSCM experiments. Carbon chemical shifts in the unsubstituted rings occur at approximately 125 ppm (C5); 128 ppm (C6); 130 ppm (C7); 128 ppm (C8); and 36 ppm (C9). The methylene protons appears as AB doublets at approximately 4.2 and 3.8 ppm. All sulfoxides have the same, pseudo‐equatorial geometry.
Proton‐ionizable crown compounds. 20. The synthesis of polyazatriazolo‐, polyazabistriazolo‐ and bispyridono‐crown ligands containing lipophilic hydrocarbon substituents
Authors: Bradshaw Jerald S. , Krakowiak Krzysztof E. , Huszthy Peter , Izatt R. M.
Published: March 2009

Four new macrocyclic polyaza‐crown compounds containing a triazole subcyclic group and two to five lipophilic hydrocarbon substituents have been prepared from the appropriate polyamine and N‐THP‐protected 2,5‐triazoledimethyl dichloride. N,N,N',N'‐Tetrabenzyltetraazabistriazolo‐18‐crown‐6 was prepared from N,N'‐dibenzylethylenediamine and N‐THP‐protected 2,5‐triazoledimethyl dichloride. Biscyclohexano‐bispyridono‐18‐crown‐6 was prepared from trans‐ 1,2‐cyclohexanediol and THP‐protected 4‐hydroxy‐2,6‐pyridinedimethyl ditosylate.
Study on the murexide reaction. V
Authors: Koyama Matajiro , Kozuka Hiroshi , Takada Atsushi
Published: March 2009

Although the reaction of caffeine with hydrogen peroxide/hydrochloric acid or nitric acid and then with ammonia has been known to give a purple coloration (Murexide reaction), the use of hydrazine instead of ammonia is found to provide no purple coloration. The reaction of caffeine with hydrogen peroxide/hydrochloric acid and then with hydrazine hydrate afforded a yellow reaction mixture, from which 4‐methyl‐6‐(N‐methylcarbamoyl)‐3,5‐dioxo‐2,3,4,5‐tetrahydrotriazine 9, oxalyl hydrazide 10 and hydroxylamine hydrochloride were isolated. The reaction of caffeine with nitric acid and then with hydrazine hydrate furnished a yellow reaction mixture, from which 8‐amino‐1,3,7‐trimethyl‐2,6‐dioxo‐1H,3H,7H‐xanthine 11, 9 and hydroxylamine nitrate were isolated. Compound 9 was clarified to be produced from 3‐hydroxy‐4,6‐dimethyloxazolo[4,5‐d]pyrimidine‐2,5,7(3H,4H,6H)‐trione 3 and 1,3‐dimethylalloxan 7 by the ring transformation with hydrazine.
Synthesis of 2‐Aryl‐3‐hydroxy‐4,9‐dihydrocyclohepta[b]pyran‐4,9‐diones
Authors: Jin Young‐Zhi , Jin Zhong‐Tian , Imafuku Kimiaki
Published: March 2009

3‐(2‐Bromoacetyl)tropolone (1) reacted with benzaldehydes 2a‐g in the pressence of alkali at low temperature to give 2‐aryl‐3‐hydroxy‐4,9‐dihydrocyclohepta[b]pyran‐4,9‐diones 3a‐g in good yields.
(±)‐5′‐Nor ribofuranoside carbocyclic guanosine
Authors: Patil Sharadbala D. , Schneller Stewart W.
Published: March 2009

The synthesis of the guanine derivative (±)‐2‐amino‐1,9‐dihydro‐9‐[(1′α,2′β,3′β,4′α)‐(2′,3′,4′‐trihydroxy‐1′‐cyclopentyl]‐6H‐purin‐6‐one (2) is described. This compound is viewed as the carbocyclic ribofuranoside guanine nucleoside analogue lacking the 5′‐methylene.
The parent of 2‐(4,5‐dihydro‐1H‐tetrazol‐5‐ylidene)‐2‐cyanoacetate: Synthesis and reactivity X‐ray structure of (E)2‐[1‐(2,2‐dimethylpropyl)‐4,5‐dihydro‐1H‐tetrazol‐5‐ylidene]‐2‐cyanoacetate
Authors: Saalfrank Rolf W. , Lurz Claus‐Jürgen , Wirth Uwe , Von Schnering Hans Georg , Peters Karl
Published: March 2009

Reaction of 3,3‐diazido‐2‐cyanoacrylate 5 with four moles of ammonia gives tetrazolyl‐bisammonium salt 7. The key‐intermediate is the amino‐vinyl azide 6 which spontaneously undergoes a 1,5′ ring‐closure reaction followed by double deprotonation. Treatment of 7 with hydrochloric acid yields the parent of 2‐(4,5‐dihydro‐1H‐tetrazol‐5‐ylidene)‐2‐cyanoacetate 9 (R = Me, Et) as the only tautomer. Regiospecific monoalkylation of bisammonium salt 7a with dimethyl sulfate and reaction of ammonium salt 12 with hydrochloric acid gives (E)2‐(1‐methyl‐4,5‐dihydro‐1H‐tetrazol‐5‐ylidene)‐2‐cyanoacetate (13) (X‐ray structure of derivative 14). Compound 13 can also be obtained from vinyl azide 10 and methylamine. This experiment as well as AM1 calculations of 9a, 23 and 24 strongly favour tautomer 9a.
Synthesis of 1,8‐, 1,6‐ and 3,6‐dichloro‐9H‐thioxanthen‐9‐ones
Authors: Okabayashi Ichizo , Fujiwara Hidetoshi , Tanaka Chika
Published: March 2009

Cyclization of 2‐chloro‐6‐[(3‐chlorophenyl)thio]benzoic acid (2) gave a mixture of 1,8‐, 3, and 1,6‐dichloro‐9H‐thioxanthen‐9‐ones 4. The mixture was converted to 1,8‐diamino‐ 7, and 1‐amino‐6‐chloro‐9H‐thioxanthen‐9‐ones 8, from which 3 and 4 were prepared separately, respectively. From a mixture of 4 and 3,6‐dichloro‐9H‐thioxanthen‐9‐one (11) obtained by cyclizing 4‐chloro‐2‐[(3‐chlorophenyl)thio]benzoic acid (10) was separated 11 by conversion of 4 to 8.
An improved synthesis of 3,6‐diamino‐1,2,4,5‐tetrazine. II. From triaminoguanidine and 2,4‐pentanedione
Authors: Coburn M. D. , Buntain G. A. , Harris B. W. , Hiskey M. A. , Lee K.‐Y. , Ott D. G.
Published: March 2009

A new synthesis for the title compound that gives an 80% overall yield was developed. Treatment of triaminoguanidine monohydrochloride (1) with 2,4‐pentanedione (2) gave 3,6‐bis(3,5‐dimethylpyrazol‐1‐yl)‐1,2‐dihydro‐1,2,4,5‐tetrazine (3) in 80–85% yield. Oxidation of 3 with nitric oxide or nitrogen dioxide to 3,6‐bis(3,5‐dimethyylpyrazol‐1‐yl)‐1,2,4,5‐tetrazine (4) followed by ammonolysis of 4 gave 3,6‐diamino‐1,2,4,5‐tetrazine (5) in guantitatively yields.
Preferred conformations of some 2‐pyridyl substituted thiourea derivatives. A reinvestigation of NMR spectral data
Authors: Kascheres Albert , Ueno Missao
Published: March 2009

A previous report involving 1H nmr spectra of some 1‐phenyl and 1‐benzoyl 3‐(2‐pyridyl)thioureas was reinvestigated and found to be incorrect. Analysis of the data permits the designation of preferred conformations for these systems.
Reaction of tris(alkylthio)cyclopropenyl cations with 2‐pyridylmagnesium bromide as a new route to indolizines
Authors: Kojima Hideo , Kinoshita Yasuo , Matsumura Noboru , Inoue Hiroo
Published: March 2009

The reaction of tris(isopropylthio)‐ and tris(tert‐butylthio)cyclopropenylium perchlorates 1a and 1b with 2‐pyridylmagnesium bromide in dry tetrahydrofuran at room temperature gave 1,2,3‐tris(isopropylthio)‐ and 1,2,3‐tris(tert‐butylthio)indolizines 2a and 2b, respectively, in high yields.
Total assignment of the proton and carbon NMR spectra of the alkaloid quindoline — utilization of HMQC‐TOCSY to indirectly establish protonated carbon‐protonated carbon connectivities
Authors: Spitzer Timothy D. , Crouch Ronald C. , Martin Gary E. , Sharaf Maged H. M. , Schiff Paul L. , Tackie Albert N. , Boye Gilbert L.
Published: March 2009

The reisolation of the indoloquinoline alkaloid quindoline (also known as norcryptolepine) from Cryptolepis sanguinolenta is reported. The structure was unequivocally confirmed by two‐dimensional nmr methods; the proton and carbon spectra were assigned for the first time. Because of congestion in the proton spectrum HMQC‐TOCSY was used as an alternative to the more familiar COSY experiment. In addition to establishing proton‐proton connectivities, HMQC‐TOCSY affords the added benefit of providing, in an indirect sense, connectivity information between protonated carbons.
Studies on pyrazines. 24. A simple and versatile synthetic method for 3‐alkoxy‐ and 3‐aminopyrazinecarbonitriles
Authors: Sato Nobuhiro , Matsui Nobuo
Published: March 2009

New and concise synthetic methods of 3‐alkoxy‐ and 3‐aminopyrazinecarbonitriles by nucleophilic displacement of 3‐phenylsulfonylpyrazinecarbonitriles are reported.
Studies on phenothiazines. Part 16. Synthesis and spectral studies of substituted 1,2‐dichlorophenothiazines
Authors: Gupta R. R. , Saraswat Vandana , Gupta Archana , Jain Mukesh , Gupta Vandana
Published: March 2009

Synthesis of the title compounds by the Smiles rearrangement has been reported. 1,2‐Dichloro‐7‐substituted phenothiazines have been prepared by the Smiles rearrangement of 3,4‐dichloro‐2‐formamido‐2′‐nitro‐4′‐substituted‐diphenyl sulphides. The latter were obtained by the formylation of the diphenyl sulphides obtained by the condensation of 2‐amino‐3,4‐dichlorobenzenethiol with o‐halogenonitrobenzenes. 9‐Nitrophenothiazines have been prepared by the reaction of 2‐amino‐3,4‐dichlorobenzenethiol with substituted o‐halonitrobenzenes containing a nitro group at both ortho positions to the halo atom in which Smiles rearrangement occurs in situ. The ir, nmr and mass spectral studies are also included.
Synthesis of 2,3,4,5‐tetranitropyrrole
Authors: Hinshaw Jerald C. , Edwards W. Wayne , George Clifford , Gilardi Richard
Published: March 2009

Dealkylation of 1‐tert‐butyl‐2,3,4‐trinitropyrrole in boiling trifluroacetic acid gave 2,3,4‐trinitropyrrole, the structure of which was confirmed by X‐ray crystallography. Treatment of this trinitropyrrole with nitric acid/oleum briefly at 60° gave 2,3,4,5‐tetranitropyrrole.
Reduction of substituted 1H‐4,5‐dihydroimidazolium salts
Authors: Salerno Alejandra , Ceriani Vanina , Perillo Isabel A.
Published: March 2009

Reactions of several substituted 1H‐4,5‐dihydroimidazolium salts 1 with nucleophilic and electrophilic reducing agents acting via hydride transfer were explored. Reaction of compounds 1 with lithium aluminum hydride in THF afforded the corresponding imidazolidines 2. When alkaline borohydrides (sodium borohydride, potassium borohydride, sodium cyanoborohydride) in ethanol at room temperature were used, partial or total over‐reduction of compounds 2 leading to N,N,N'‐trisubstituted ethylenediamines took place on occasion. Results may be explained taking into account that reductive cleavage of 2 proceeds via a stabilized iminium ion present in protic solvents. Treatment of compounds 1 with an excess of borane in THF afforded the corresponding imidazolidines 2 or their borane complexes, according to the substituent type.