bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of 5‐phenylpyrrolo[1,2‐b][1,2,5]‐triazepin‐2(3H)‐ones
Authors: Hamer R. Richard L. , Effland Richard C. , Klein Joseph T. , Huger Francis P. , Wilker Jeffrey C.
Published: April 2009

The synthesis of a series of 5‐phenylpyrrolo[1,2‐b][1,2,5]triazepin‐2(3H)‐ones 1 as potential anxiolytic agents is described. Benzoylation of 1‐phthalimidopyrrole, followed by hydrolysis, gave the 1‐amino‐2‐benzoylpyrroles 3. These were further functionalized to give the penultimate 1‐aminoacetamido‐2‐benzoylpyrroles 8 and 9, which were cyclized to the target pyrrolotriazepines 1.
Synthesis of some methylfurochromones as potential photochemotherapeutic agents
Authors: Rodighiero P. , Pastorini G. , Chilin A. , Manzini P. , Guiotto A.
Published: April 2009

A number of new methylfurochromones with a linear psoralen like structure or an angular angelicin like structure were synthetized. The synthesis were performed starting from 7‐hydroxychromones variously methylated on which the furan ring was built. Methyl groups have been introduced into positions which look most promising for enhancement of the photoreactivity of the compound towards DNA.
Synthesis of 7,8,9,10‐tetrahydropyrido[3′,4′:4,5]pyrrolo[2,3‐c]quinolines
Authors: Schönafinger Karl , Yasenchak Christine M. , Vollman Anne , Ong Helen H.
Published: April 2009

A series of structurally novel 7,8,9,10‐tetrahydropyrido[3′,4′:4,5]pyrrolo[2,3‐c,]quinolines, 4a‐c, were synthesized via a facile Fischer indole cyclization from the appropriately substituted hydrazinoquinolines 2a‐c. Acetamides 4a,c were hydrolyzed to 5a,b and further converted to tertiary amines 6a‐c. Potent antihypertensive activity has been observed with a number of the title compounds as well as the intermediate 3a.
Synthesis of 1,3,7,9,11,12,14‐heptazapentacene‐2,4,8,10‐(14H,3H,9H,12H)‐tetraones (mixed flavins) with oxidizing ability
Authors: Yoneda Fumio , Koga Masakazu
Published: April 2009

1,3,7,9,11,12,14‐Heptazapentacene‐2,4,8,10(14H,3H,9 H,12H)‐tetraones (mixed flavins) were synthesized by the cyclization of 1,5‐dihydro‐8‐[N‐alkyl‐N‐(5‐nitrouracil‐6‐yl)]‐amino‐5‐ deazaflavins with the Vilsmeier reagent. The mixed flavins oxidized alcohol under neutral conditions in sunlight.
Synthesis of 1‐Aryl‐1H‐pyrazolecarbonitriles and related derivatives
Authors: Beck James R. , Lynch Michael P. , Wright Fred L.
Published: April 2009

The synthesis of 1‐aryl‐5‐cyano‐1H‐pyrazole‐4‐carboxylic acid, ethyl esters 1 is described. Subsequent chemistry led to relatively simple and unique pyrazole derivatives. Most important of these are 1‐aryl‐5‐(aminocarbonyl)‐1H‐pyrazole‐4‐carboxylic acids 2, which are chemical hybridizing agents in wheat and barley. The regioselective hydrolysis of 1‐(3‐chlorophenyl)‐1H‐pyrazole‐4,5‐dicarboxylic acid, dimethyl ester (7b) and subsequent chemistry is also described.
Tetrakis(alkylthio)thieno[3,4‐c]thiophene: Synthesis, stability, and reactivity
Authors: Yoneda Shigeo , Tsubouchi Kenji Ozaki, Akira , Kojima Hideo , Yanagi Kazunori
Published: April 2009

The synthesis of tetrakis(alkylthio)thieno[3,4‐c]thiophenes la‐e by the dimerization reaction of bis(alkylthio)cyclopropenethiones is described. The remarkable thermodynamic and kinetic stability suggests the significant electron‐accepting conjugation of the alkylthio substituents to the carbanionic 1, 3, 4, and 6 carbons in the framework. The isopropylthio‐ and ethylthio‐substituted thienothiophenes 1d and 1e undergo cycloaddition reactions with dienophiles such as N‐phenylmaleimide and dimethyl acetylenedicarboxylate to give the cycloadducts in moderate yields.
Spectroscopic identification of some derivatives of 3,4‐diamino‐4H‐1,2,4‐triazole and 3‐Hydrazino‐4H‐1,2,4‐triazole
Authors: Emilsson Håkan , Selander Hans
Published: April 2009

Spectroscopic methods (ir, 1H‐ and 13C‐nmr, ms and uv) have been used for the structural elucidation and identification of different isomeric 1,2,4‐triazole derivatives, obtained by cyclisation reactions from appropriate diaminoguanidines. The four compounds 3,4‐diamino‐4H‐1,2,4‐triazole, 3‐hydrazino‐4H‐1,2,4‐triazole, 3‐amino‐4‐(2,6‐dichlorobenzylideneamino)‐4H‐1,2,4‐triazole and 3‐(2,6‐dichlorobenzylidenehydrazino)‐4H‐1,2,4‐triazole, were chosen as representative structures to illustrate the general spectroscopic properties for 3,4‐diamino‐ and 3‐hydrazino‐substituted 4H‐1,2,4‐triazoles and the corresponding hydrazones, with different substituents in the 5‐position of the triazole ring (alkyl‐, aralkyl‐, mercapto‐, hydroxy‐ and amino‐groups). Nmr and uv spectroscopy were found to be the best methods for confirmation of the different series of hydrazones, while ir and nmr were found to be suitable for the structural elucidation of compounds in the series of 3,4‐diamino‐ and 3‐hydrazino‐4H‐1,2,4‐triazoles, respectively.
12H‐dibenzo[d,g][1,3,2]dioxaphosphocins: Synthesis, structures and “through‐space” spin‐spin coupling in their NMR spectra
Authors: Goddard John D. , Payne Alan W. , Cook Nick , Luss Henry R.
Published: April 2009

A series of 12H‐dibenzo[d,g][1,3,2]dioxaphosphocins has been prepared by the reactions of bisphenols with either ethyl phosphorodichloridate or phosphorus pentasulfide. The structures of a pair of cis and trans isomers in this series were elucidated by X‐ray crystallography. Both isomers adopt the boat‐chair conformation in the solid state with the bulky group at C‐12 in the pseudo‐equatorial position. Some flattening of the heterocyclic ring due to the pseudo‐axial ethoxy group was observed in the cis isomer. A novel transannular cyclisation reaction was observed in the mass spectra of the cis isomers and this has allowed us to assign the configurations of all the isomers in the series. The pmr spectra of the compounds have been explained in terms of the rigid boat‐chair conformation; however, as bulky groups were introduced at C‐12, signs of mobility were observed for the cis isomers and an equilibrium was established with mobile boat forms. A stereospecific long‐range coupling between P and the proton at C‐12 could be transmitted “through space” by the antiperiplanar lone‐pair electrons on the ring oxygen atoms.
Cyclization of a cysteine conjugate ofN‐(3,5‐Dichlorophenyl)succinimide
Authors: Shih Hsien‐Cheng , Rankin Gary O.
Published: April 2009

N‐(3,5‐Dichlorophenyl)‐2‐cysteinylsuccinimide methyl ester hydrochloride (5) was prepared fromN‐(3,5‐dichlorophenyl)maleimide (3) and cysteinyl methyl ester hydrochloride. Attempted neutralization of the cysteine conjugate salt with triethylamine resulted in spontaneous cyclization of5to form the more stable 2‐(N‐3,5‐dichlorophenylcarbamoylmethyl)‐5‐carbomethoxy‐1,4‐thiazine‐ 3‐one (6). Similar results might be expectedin vivoshould these metabolites of succinimides be formed.
Synthese et isomerisation de methoxycarbonyl‐5 dihydropyrannones‐2
Authors: Rocher Jean‐Philippe , Ahmar Mohammed , Paris Joelle
Published: April 2009

La synthèse de méthoxycarbonyl‐5 méthyl‐4 dihydro pyrannones‐2 est réalisée par condensation du méthyl‐3 glutaconate de diméthyle sur des cétones. Les conditions opératoires permettant d'isoler sélectivement des pyrannones isomères sont discutées. La structure des différents produits réactionnels est établie par spectrométrie rmn 1H et 13C.
N‐ and C‐sulfenylation of 1‐(1,2‐oxazol‐3 (and 5)‐yl)‐3‐alkylureas with organic sulfenyl chlorides
Authors: Pilgram Kurt H. , Gale Laird H.
Published: April 2009

Condensation of chlorocarbonylsulfenyl chloride 1 with 1‐(5‐(1,1‐dimethylethyl)‐1,2‐oxazol‐3‐yl)‐3‐methylurea 4a has been found to give isomeric 2,4‐disubstituted‐1,2,4‐thiazolidine‐3,5‐diones 5 and 6. Assignments are confirmed by the X‐ray structure data of 6. Sulfenylation with alkoxycarbonylsulfenyl chlorides 7 and trichloromethylsulfenyl chloride 10 of 4 occurs exclusively on N‐1 rather than N‐3 of the urea moiety. With the isomeric 1‐[3‐(1,1‐dimethylethyl)‐1,2‐oxazol‐5‐yl]‐3‐methylurea 14 and ethoxycarbonylsulfenyl chloride 7b, C‐sulfenylated derivatives 15 and 16 are formed in low yield.
Synthesis of 5H‐Triazolo[1,5‐d]‐ and 5H‐ Tetrazolo‐ [1,5‐d]thieno[3,2‐f]‐1,4‐diazepin‐6(7H)‐ones
Authors: Shishoo C. J. , Devani M. B. , Ullas G. V. , Ananthan S. , Bhadti V. S.
Published: April 2009

5H‐Triazolo[1,5‐d]‐ and 5H‐tetrazolo[1,5‐d]thieno[3,2‐f]‐1,4‐diazepin‐6(7H)‐ones have been obtained by the base catalysed ring expansion reaction of 5‐chloromethyl‐1,2,4‐triazolo[1,5‐c]‐ and 5‐chloromethyltetrazolo‐ [1,5‐c]thieno[3,2‐e]pyrimidines. The required thienopyrimidine derivatives were synthesized from 2‐amino‐3‐triazolyl‐ and 2‐amino‐3‐tetrazolylthiophenes by acylation, followed by dehydrative cyclization.
Synthesis of certain exocyclic thiazole nucleosides related to tiazofurin. Formation of a unique acycloaminonucleoside
Authors: Sanghvi Yogesh S. , Larson Steven B. , Robins Roland K. , Revankar Ganapathi R. , Gupta Pranab K. , George Rose D. , Dalley N. Kent
Published: April 2009

Several thiazole nucleosides structurally related to tiazofurin (1) and ARPP (2) were prepared, in order to determine whether these nucleosides had enhanced antitumor/antiviral activities. Ring closure of 1‐(2,3,5‐tri‐O‐benzoyl‐β‐D‐ribofuranosyl)thiourea (4) with ethyl bromopyruvate (5a) gave ethyl 2‐(2,3,5‐tri‐O‐benzoyl‐β‐D‐ribofuranosylamino)thiazole‐4‐carboxylate (6a). Treatment of 6a with sodium methoxide furnished methyl 2‐(β‐D‐ribopyranosylamino)thiazole‐4‐carboxylate (9). Ammonolysis of the corresponding methyl ester of 6a gave a unique acycloaminonucleoside 2‐[(1R, 2R, 3R, 4R)(1‐benzamido‐2,3,4,5‐tetrahydroxypentane)amino]‐thiazole‐4‐carboxamide (7a). Direct glycosylation of the sodium salt of ethyl 2‐mercaptothiazole‐4‐carboxylate (12) with 2,3,5‐tri‐O‐benzoyl‐D‐ribofuranosyl bromide (11) gave the protected nucleoside 10, which on ammonolysis provided 2‐(β‐D‐ribofuranosylthio)thiazole‐4‐carboxamide (3b). Similar glycosylation of 12 with 2‐deoxy‐3,5‐di‐O‐p‐toluoyl‐α‐D‐erythro‐pentofuranosyl chloride (13), followed by ammonolysis gave 2‐(2‐deoxy‐β‐D‐ribofuranosylthio)thiazole‐4‐carboxamide (3c). The structural assignments of 3b, 7a, and 9 were made by single‐crystal X‐ray analysis and their hydrogen bonding characteristics have been studied. These compounds are devoid of any significant antiviral/antitumor activity in vitro.
Synthesis of 3‐(2‐Aminoethyl)pyrrole Derivatives
Authors: Demopoulos Vassilis J.
Published: April 2009

3‐(2‐Di‐n‐propylaminoethyl)pyrrole (1a) was prepared in good yield by reduction of pyrrole‐3‐(N,N‐di‐n‐propylglyoxamide) (9) with lithium aluminum hydride. 3‐(2‐Di‐n‐propylaminoethyl)‐5‐acetylpyrrole (1b) was prepared by first acetylation of 1‐p‐toluenesulfonyl‐3‐(2‐di‐n‐propylaminoethyl)pyrrole (6) followed by hydrolysis of the p‐toluenesulfonyl substituent. The starting material 6 was prepared by homologation of 1‐(p‐toluenesulfonyl)pyrrole‐3‐carboxaldehyde (3) to the corresponding acetaldehyde followed by reductive amination of the latter.
17O NMR investigation of acetyl and formylthiophenes, furans and pyrroles
Authors: Boykin David W. , Rhodes R. Allen
Published: April 2009

The 17O nmr chemical shifts of 20 acetyl and formylthoiphenes, furans, and pyrroles are reported. The chemical shifts qualitatively correlate with the electronic character of the heterocyclic rings. The effect of steric factors are noted for the 17O chemical shifts of alkyl substituted acetylthiophenes and for N‐methylpyr‐roles.
A practical synthesis of ethyl 1,2,4‐triazole‐3‐carboxylate and its use in the formation of chiral 1′,2′‐seco‐nucleosides of ribavirin
Authors: Vemishetti Purushotham , Leiby Robert W. , Abushanab Elie , Panzica Raymond P.
Published: April 2009

A practical and efficient synthesis of ethyl 1,2,4‐triazole‐3‐carboxylate (6a, R' = H) from ethyl carboethoxyformimidate hydrochloride (7) is described. Alkylation of this heterocycle with the chloromethyl ethers of 1,3‐O‐dibenzylbutane‐1,2R,3S‐triol (8a) and 1,3,4‐O‐tribenzylbutane‐1,2R,3S,4‐tetrol (8b), followed by conversion of the ester function to the amide and deprotection, furnished the chiral 1′,2′‐seco‐nucleosides of ribavirin, 11a and 11b, respectively.
Synthese D'isoquinoleinediones‐5,8 apparentees a la mimocine
Authors: Croisy‐Delcey Martine , Huel Christianne , Bisagni Emile
Published: April 2009

L'anhydride selenieux transforme la méthyl‐1 diméthoxy‐5,8 isoquinoléine en donnant la formyl‐1 diméthoxy‐5,8 isoquinoléine. Si l'oxydation de la [(méthyl‐2 propanediol‐1,3) aminométhyl‐2]‐1 diméthoxy‐5,8 isoquinoléine, dérivée de ce dernier composé, par le nitrate de cerium ammoniacal, ne fournit pas le quinone attendue, au contraire et dans les měmes conditions les acylaminométhyl‐1 diméthoxy‐5,8 isoquinoléines, permettent de préparer les quinones apparentées à la mimocine.

L'aminométhyl‐1 diméthoxy‐5,8 isoquinoléine intermédiaire est préparée en introduisant directement la fonction aminométhyle protégée par le groupement phtalimido.
Acetylenchemie. 9. Mitt. Anellierte imidazole aus N‐propinylamid‐vorstufen
Authors: Reisch Johannes , Scheer Mathias
Published: April 2009

2‐(N‐Formyl‐N‐prop‐2′‐inyl)‐aminopyridin cyclisiert in siedender Ameisensäure zum 3‐Methylimidazo‐[1,2‐a]pyridin, wobei 3‐Methylen‐2H‐imidazo[1,2‐a]pyridin als Intermediat auftritt. Unter den gleichen Bedingungen bildet sich aus dem 1,3‐Diprop‐2‐inylpyrimido[4,5‐b]chinolin‐2,4‐dion das 1‐Methylimidazo‐[1,2‐a]chinolin‐4‐carbonsäure‐N‐prop‐2′‐inylamid und aus dem 1‐Prop‐2′‐inylbenzo[b][1,8]naphthyridin‐2‐on als neues Ringsystem das 1‐Methyl‐benzo[b]imidazo[1,2,3‐ij][1,8]naphthyridin‐4,7‐dion.
Dibenzo[d,h][1,3,6,7,2]dioxadithiasilonin: Synthesis and characterization
Authors: Pastor Stephen D. , Denney Dorothy Z.
Published: April 2009

The reaction of 2,4‐di‐t‐butylphenol, 4, with sulfur monochloride gave the trithiobisphenol 5 rather than the expected dithiobisphenol 7. The thiol 6 was obtained by the reduction of 5 with zinc under acidic conditions. The dithiobisphenol 7 was prepared by the oxidative coupling of 6 with iodine under alkaline conditions. The dibenzo[d,h][1,3,6,7,2]dioxadithiasilonin 8 was prepared by the reaction of 7 with dichlorodimethylsilane using triethylamine as an acid acceptor. No change was observed in the 1H nmr spectrum of 8 upon cooling to −55°, which suggests that the ΔG* for ring inversion is less than the corresponding eight‐membered dibenzo[d,g][1,3,2]dioxasilocin and dibenzo[d,g][1,3,6,2]dioxathiasilocin 1 and 2, respectively. The spectral data and elemental analysis are fully in accord with the nine‐membered silonin structure.
Electron impact mass spectrometry of 3‐hydroxy‐3,4,5,6‐tetrahydro‐2H‐[1]benzoxocines. A comparison with the behaviour of isomeric 2‐hydroxymethyl‐2,3,4,5‐tetrahydro‐[1]‐benzoxepines and 1,2‐epoxy‐5‐(2‐hydroxyphenyl)pentane
Authors: Bravo Pierfrancesco , Ticozzi Calimero , Pelli Beatrice , Traldi Pietro
Published: April 2009

The mass spectrometric behavior of 3‐methyl‐3‐hydroxybenzoxocines has been studied in detail by means of linked scans and mass analyzed ion kinetic energy spectrometry. The structure of the molecular ion and the fragmentation processes are strictly related to the structure of the neutral moieties.

The possible isomerization of 3‐hydroxy‐10‐methoxy‐3‐methyl‐3,4,5,6‐tetrahydro‐2H‐[1]benzoxocine to 2‐methyl‐2‐[3‐(3′‐methoxy‐2′‐hydroxy)phenyl]pentyloxirane and to 2‐hydroxymethyl‐9‐methoxy‐2‐methyl‐2,3,4,5‐tetrahydro[1]benzoxepine is investigated.
Regioselectivity in the 1,3‐dipolar cycloaddition reaction of unsymmetric pyridinium dicyanomethylides with dimethyl acetylenedicarboxylate and methyl propiolate: An example of dipole‐dipole control of regioselectivity?
Authors: Matsumoto Kiyoshi , Ikemi Yukio , Konishi Hideyuki , Shi Xiao‐Lan , Uchida Takane , Aoyama Kinuyo
Published: April 2009

A study of the cycloaddition behavior of a series of unsymmetric pyridinium dicyanomethylides with dimethyl acetylenedicarboxylate and methyl propiolate has been carried out. The 1,3‐dipolar cycloaddition proceeds in good yield with high regioselectivity to produce the corresponding indolizines and 1:1 adducts. The reactions of isoquinolinium dicyanomethylide follow frontier orbital predictions. In contrast, polar 3‐substituted pyridinium dicyanomethylides gave predominantly the corresponding 8‐isomers regardless of the substituents. The results can be explained by dipole‐dipole interactions.
An unusual ring transformation: Reaction of phenyl 4‐chromone‐3‐sulfonate with methyl 3‐aminocrotonate
Authors: Löwe Werner , Jeske Peter , Kradepohl Anneliese
Published: April 2009

The novel benzoxathiinopyridines 8 and 9 were synthesized by ring transformation of phenyl 4‐chromone‐3‐sulfonate (1) with methyl 3‐aminocrotonate (2). The structures of 8 and 9 were determined by spectroscopic methods and the reaction courses for the formation of these compounds are discussed.
Synthesis of 3‐aryl‐6H‐isoxazolo[3,4‐d]pyrazolo[3,4‐b]pyridines and 3‐aryl‐6H‐isoxazolo[5,4‐d]pyrazolo[3,4‐b]pyridines
Authors: Shutske Gregory M. , Huger Francis P.
Published: April 2009

The synthesis and characterization of a number of 3‐aryl‐6H‐isoxazolo[3,4‐d]pyrazolo[3,4‐b]pyridines and 3‐aryl‐6H‐isoxazolo[5,4‐d]pyrazolo[3,4–6]pyridines from common precursors, 5‐benzoyl‐4‐chloro‐1H‐pyrazolo‐[3,4‐b]pyridines, has been described. The structures were determined by unambiguous chemical synthesis and by isolation and 13C nmr analysis of some key, isolated, intermediates. The ability of these compounds to displace [3H]flunitrazepam from CNS binding sites was also observed.
Novel synthesis of dianthalexin (phytoalexin) analogues preparation
Authors: Hauteville M. , Ponchet M. , Ricci P. , Favre‐Bonvin J.
Published: April 2009

Two phytoalexins, previously isolated from carnation infected by Phytophthora parasitica D., were synthesized: 2‐phenyl‐7‐hydroxy‐4H‐3,l‐benzoxazin‐4‐one (Dianthalexin) and 2‐(2‐hydroxybenzoyl)‐amino‐4‐methoxybenzoic acid (Dianthramide A). The first one was obtained by using potassium t‐butoxide in dimethylformamide to prevent its heterocycle opening. Five novel other analogous compounds were also prepared.
Synthesis of some novel 7‐substituted quinolonecarboxylic acids via nitroso and nitrone cycloadditions
Authors: Ziegler Carl B. , Bitha Panayota , Lin Yang‐I
Published: April 2009

1‐Ethyl‐6‐fluoro‐7‐hydroxylamino‐1,4‐dihydro‐4‐oxoquinoline‐3‐carboxylic acid 7 can be either oxidized to the corresponding nitroso intermediate 8 or converted to the methylene nitrone 9. Both intermediates form cycloaddition products with selected dienes and olefins respectively. Also, the preparation of 1‐ethyl‐6‐fluoro‐7‐(hexahydro‐2‐methyl‐5H‐pyrrolo[3,4‐d]isoxazol‐5‐yl)‐3‐quinolinecarboxylic acid 5 via a nitrone cycloaddition is presented.
Cyclocondensation of 3‐amino‐2‐hydrazino‐4(3H)‐pyrimidinones with dimethyl acetylenedicarboxylate. Formation of 1‐amino‐2,6‐dihydro‐2,6‐dioxo‐1H‐pyrimido[1,2‐b][1,2,4]triazine‐3‐acetic acid esters
Authors: Bitha Panayota , Hlavka Joseph J. , Lin Yang‐I
Published: April 2009

[(1‐Amino‐6‐hydroxy‐2(1H)‐pyrimidinylidene)hydrazone]butanedioic acid dimethyl esters 3, formed from 3‐amino‐2‐hydrazino‐4(3H)‐pyrimidinones and dimethyl acetylenedicarboxylate in acetic acid at room temperature, underwent a facile, thermal rearrangement to 1‐amino‐2,6‐dihydro‐2,6‐dioxo‐1H‐pyrimido‐[1,2‐b]‐[1,2,4]triazine‐3‐acetic acid methyl esters 6 in hot acetic acid.
A new heterocyclic structure. The [1,2,3]triazolo[1,5‐d][1,2,4]triazine
Authors: Bianchi Mario , Butti Alina , Perronnet Jacques
Published: April 2009

The hydrazone derivatives of 4‐benzoyl‐1,2,3‐triazole can easily be cyclised by reaction with various organic reagents (ortho esters, aldehyde and ketone compounds, phosgene, etc) which result in the incorporation of the introduced reagent's carbon atom into the new six membered ring. The newly created C‐N bond of the resulting [1,2,3]triazolo[1,5‐d][1,2,4]triazines displays a particular sensitivity due to the electron attracting effect of the triazole ring. Some mechanistic considerations are proposed to account for the observed results.
A facile synthesis of 3‐amino‐5‐substitutedaminoisothiazole‐4‐carboxylic acid derivatives
Authors: Shishoo C. J. , Devani M. B. , Ananthan S. , Bhadti V. S. , Ullas G. V.
Published: April 2009

A facile, general and one‐pot method for the preparation of 3‐amino‐5‐substituted‐aminoisothiazole‐4‐carboxylic acid derivatives, in high yields, by the aminative cyclization of 3‐amino‐3‐mercaptoacrylonitriles is described.
Lanthanide(III) ion catalyzed reaction of ammonia and nitriles: Synthesis of 2,4,6‐trisubstituted‐s‐triazines
Authors: Forsberg John H. , Spaziano Vincent T. , Klump Stephen P. , Sanders Kathleen M.
Published: April 2009

Lanthanum and yttrium trifluoromethanesulfonates at 1 mole % concentration, have been found to catalyze a reaction between ammonia and aromatic nitriles to yield symmetrically substituted 2,4,6‐triaryl‐s‐triazines. The generally high yields and relatively mild reaction conditions of this procedure suggest it as an alternative to other aromatic nitrile cyclotrimerization reactions. Of the aliphatic nitriles studied, acetonitrile and cyclopropanecarbonitrile gave good yields of triazine, propionitrile and butyronitrile gave significantly reduced yields of triazines 3b and 3c respectively. Rearrangement of 3a and 3b to alkylated‐4‐aminopyrimidines was observed.
A convenient preparation of 3‐methyl‐3,4‐dihydro‐2(1H)‐quinazolinone
Authors: Golec Frederick A. , Reilly Laurence W.
Published: April 2009

3‐Methyl‐3,4‐dihydro‐2(1H)‐quinazolinone (5) can be prepared in good yield and quality from o‐nitrobenzyl chloride (1). The three‐step sequence requires no purification of intermediates or final product.
A new synthetic route to 4,6‐diarylpyridazinones and some of their derivatives
Authors: Coudert P. , Couquelet J. , Tronche P.
Published: April 2009

A novel approach to the titled ring system starting from conveniently available chalcones 1 is proposed. It involves a catalysed exchange of hydrogen cyanide between acetone cyanohydrin and 1. The resulting γ‐ketonitriles 2 give the expected 4,6‐diarylpyridazinones 4 and 5 via hydrolysis and cyclisation by hydrazine. The action of phosphorus oxychloride on 5 followed by that of amines provides aminopyridazines 7.
Amination of 4‐nitro‐ and 4‐cyanopyridazines by liquid ammonia/potassium permanganate
Authors: Marcelis Antonius T. M. , Tondijs Hanna , Van Der Plas Henk C.
Published: April 2009

4‐Nitro‐3‐R1‐6‐R2‐pyridazines (1) (a, R1 = R2 = 2‐pyridyl; b, R1 = H, R2 = phenyl; e, R1 = H, R2 = p‐methoxyphenyl; d, R1 = R2 = H) are aminated by liquid ammonia/potassium permanganate to the corresponding 5‐amino‐4‐nitropyridazines 3a‐d. The 4‐cyano‐3‐R1‐6‐R2‐pyridazines 4a,b are only aminated in the presence of potassium amide in liquid ammonia/potassium permanganate to give the 5‐amino‐4‐cyanopyridazines 6a,b. The 5‐amino‐4‐nitropyridazines 3a,b,d are converted to the 4,5‐diaminopyridazines 7a,b,d by reduction over a Pd/C catalyst. Reaction of 7b with glyoxal leads to 5‐phenylpyrazino[2,3‐d]pyridazine (8b).
On the synthesis of 3(5)‐carbomethoxy‐4‐hetarylpyrazoles
Authors: Cativiela Carlos , De Villegas Maria D. Diaz , Mayoral José A. , Avenoza Alberto , Roy Miguel A.
Published: April 2009

3(5)‐Carbomethoxy‐4‐hetarylpyrazoles 3 can be obtained by the aromatization of the corresponding cis‐3‐benzamido‐3‐carbomethoxy‐4‐hetaryl‐Δ1‐pyrazolines 2 obtained by 1,3‐dipolar cycloaddition of diazo‐methane with methyl Z‐2‐benzamido‐3‐hetarylpropenoates 1. An explanation, based on FMO theory, for the different reactivity of the dipolarophiles with diazomethane is given.
Synthesis of benzo‐halogenated 4‐hydroxy‐2(1H)‐quinolones
Authors: Kappe Thomas , Karem Abdel S. , Stadlbauer Wolfgang
Published: April 2009

Malondianilides 3 derived from dichloro substituted anilines 2 undergo cyclization to afford 4‐hydroxy‐2(1H)‐quinolones 4 in very good yields using methane sulfonic acid‐phosphorus pentoxide as catalyst. 3,4‐Dichloro anilines 5 can be shown to yield two isomers, 7 and 8, whereas 3‐substituted anilines 9 afford merely 7‐substituted 4‐hydroxy‐2(1H)‐quinolones 11.
Acid catalyzed hydrolysis of brotizolam, a thienotriazolodiazepine: Spectroscopic study
Authors: Gallo B. , Alonso R. M. , Lete E. , Badía M. D. , Patriarche G. J. , Gelbcke M.
Published: April 2009

The acid catalyzed hydrolysis of the thienotriazolodiazepine, Brotizolam, 2‐bromo‐4‐(2‐chlorophenyl)‐9‐methyl‐6H‐thieno[3,2‐f][1,2,4]triazolo[4,3‐a][1,4]diazepine (1), has been studied spectrometrically (ir, pmr, cmr, and ms). The cleavage reaction of the azomethine bond is reversible and the open‐ring compound is in equilibrium with the ring closed compound (protonated form of the parent drug).
A novel synthesis of precocenes. Efficient synthesis and regioselective O‐alkylation of dihydroxy‐2,2‐dimethyl‐4‐chromanones
Authors: Timár Tibor , Jászberényi J. Csaba
Published: April 2009

The reactions of trihydroxybenzenes 1a‐c and 3‐methylbut‐2‐enoic acid (2) in a zinc chloride/water/phosphoryl chloride system afford either the new trihydroxyphenylbutenone derivatives 3b,c or dihydroxy‐2,2‐dimethyl‐4‐chromanones 4a‐c in good yields. Compounds 3b,c can be cyclized in high yields to 4b,c in 5% sodium hydroxide solution. Regioselective O‐alkylation of 4a‐c leads to 5a‐f in good yields. O‐Alkylation of 5a‐f, followed by reduction and dehydration, results in the formation of precocene 3 (7d) and its regioisomer 7a‐c,e,f. Methylation of 4a‐c gives 6g‐i. Subsequent reduction and dehydration affords precocene 2 (7h) and its regioisomers 7g,i.
Photophysical properties of a C6 hydrocarbon linked porphyrin dimer
Authors: Kozyrev Andrei N. , Mironov Andrei F. , Davila Jorge , Harriman Anthony
Published: April 2009

The synthesis and characterisation of a C6 hydrocarbon linked porphyrin dimer and its zinc complex is described. From fluorescence quantum yields and excited singlet and triplet state lifetimes, recorded for the dimers and the corresponding monomer species, it is suggested that the dimeric porphyrins exist in solution in open and closed conformations. The open conformations retain photophysical properties similar to those of the relevant monomeric species but the closed conformations do not fluoresce.
Synthesis and spectra of 7‐(o‐ and p‐R‐phenyl)‐10,10‐dimethyl‐8,9,10,11‐tetrahydrobenz[c]acridin‐8‐ones. Structure correction of 1,2,3,4‐tetrahydro‐2,2‐dimethyl‐5‐aryl‐6‐aza‐7,8‐benzophenanthren‐4‐ones
Authors: Cortés Eduardo , Martínez Roberto , Avila J. Gustavo , Toscano R. Alfredo
Published: April 2009

It has been reported that dimedone added to α‐arylidennaphthylamines in ethanol with formation of 1,4‐addition products derivatives of 5‐aryl‐5,6,7,8,9,10‐hexahydrobenzo[c]phenanthridin‐7‐ones, III, which are easily oxidized by chromic anhydride to the corresponding tetrahydro derivatives, IV. However, the attempted preparation of these compounds resulted instead of the formation of isomeric acridin‐8‐ones V and VI. Structures were confirmed by ir, 1H nmr, ms and X‐ray spectroscopy.
Some novel quinone‐type dyes containing naphthoquinone and related fused ring systems
Authors: Katritzky Alan R. , Fan Wei‐Qiang
Published: April 2009

A variety of 1,4‐thiazines, thiazoles, 1,4‐dithines and 2,2′‐bithiazoles containing fused naphthoquinone and related rings have been prepared. The compounds include several novel chromophoric heterocyclic system and their visible absorption spectra are discussed.
4(5)‐vinylimidazole by dehydrobromination of 1‐triphenylmethyl‐4‐(2‐bromoethyl)imidazole
Authors: Altman Janina , Wilchek Meir
Published: April 2009

1‐Triphenylmethyl‐4‐(2‐bromoethyl)imidazole undergoes elimination upon basic treatment providing an easy approach to 4(5)‐vinylimidazole whereas the N‐unsubstituted analogue leads only to substitution products.
Synthesis of 4,12‐dihydro‐4‐oxoquino‐[1,8a,8‐a,b]quinoxaline‐5‐carboxylic acid derivatives
Authors: Chu Daniel T. W. , Maleczka Robert E. , Nordeen Carl W.
Published: April 2009

The synthesis and antibacterial activity of 1‐substituted amino‐2‐fluoro‐4,12‐dihydro‐4‐oxoquino[1,8a,8‐a,b]quinoxaline‐5‐carboxylic acid derivatives are described. The synthetic route includes a carbon homologation and two intramolecular nucleophilic displacement cyclization reactions leading to the novel 4,12‐dihydro‐4‐oxoquino[1,8a,8‐a,b]quinoxaline‐5‐carboxylic acid heterocycle.
Condensed heterocycles containing the pyrimidine nucleus
Authors: Santagati Andrea , Santagati Maria , Russo Filippo , Ronsisvalle Giuseppe
Published: April 2009

Continuing earlier studies designed to obtain derivatives of 1,3,4‐thiadiazolo[3,2‐a]pyrimidin‐5‐one and of the isomeric 7‐one of pharmacological interest, some novel compounds 2 and derivatives of 6,7,8,9‐tetrahydro‐5H‐1,3,4‐thiadiazolo[2,3‐b]quinazolin‐5‐one (3) were prepared. Derivatives of pyrimido[2,1‐b]benzothiazol‐2‐one (6) and of the isomeric 4‐one derivatives 8 were also synthesized. Structural identification was obtained by 1H‐nmr, ir and mass spectra.
Synthesis of pyrimidine derivatives by the reaction of ketene dithioacetals with amides
Authors: Kohra Shinya , Tominaga Yoshinori , Hosomi Akira
Published: April 2009

Reactions of methyl 2‐cyano‐3,3‐bis(methylthio)acrylate (1a) with carboxamides 2a‐g in the presence of sodium hydride in a mixture of benzene and N,N‐dimethylacetamide took place displacement with the methylthio group to give the corresponding methyl 3‐N‐acylamino‐2‐cyano‐3‐(methylthio)acrylates 3a‐g which were readily converted to the corresponding pyrimidine derivatives at reflux in methanol in good yields. Reactions of 2‐cyano‐3,3‐bis(methylthio)acrylonitrile (1b) with the carboxamides 2a‐f gave directly pyrimidine‐5‐carbonitrile derivatives 7a‐f. Ketene dithioacetals 1a,b smoothly reacted with thioamide 2g or urea 2h,i to give the expected pyrimidine derivatives 9,10a,b. Polyfunctionalized pyrimidines, thus obtained, were also used for the synthesis of fused pyrimidine derivatives.
Benzofurans. Ketene intermediates in the perkin reaction
Authors: Brady William T. , Gu Yi‐Qi
Published: April 2009

The intermediacy of ketenes in the intramolecular reaction of ketoacids with sodium acetate in acetic anhydride to form benzofurans is demonstrated. The Perkin reaction conditions are superior to the classical ketene generation method of triethylamine dehydrochlorination of the acid chloride.
Reactions of substituted phenacyl bromides with various bases: p‐methyl‐ and p‐methoxyphenacyl bromide. II
Authors: Baghdadchi Jamil , Chan Albert P. , Hutchinson James H.
Published: April 2009

The products obtained from the reaction of p‐methyl‐ and p‐methoxyphenacyl bromide with various bases are described.
The synthesis of 1,3‐dihydro‐1‐[1‐[(4‐methyl‐4H‐6H‐pyrrolo[1,2‐a][4,1]benzoxazepin‐4‐yl)methyl]‐4‐piperidinyl]‐2H‐benzimidazol‐2‐one (1:1) maleate (CGS 9343 B, potent calmodulin inhibitor)
Authors: Boyer S. , Blazier E. , Barabi M. , Long G. , Zaunius G. , Wasley J. W. F. , Hamdan A.
Published: April 2009

A practical synthesis of the title compound7bis described in seven steps in approximately 10% overall yield. The key step in the synthesis is the formation of the unusual tricyclic ring system4viaacid catalyzed cyclization.
Polycondensed heterocycles. III. Synthesis of 5,11‐dioxo‐1,2,3,1 1a‐tetrahydro‐5H,11H‐ and 5‐oxo‐2,3,11,1 1a‐tetrahydro‐1H,5H‐pyrrolo[2,1‐c][1,4]benzothiazepine
Authors: Nacci V. , Garofalo A. , Anzini M. , Campiani G.
Published: April 2009

The syntheses of 5,11‐dioxo‐1,2,3,11a‐tetrahydro‐5H11H‐ and 5‐oxo‐2,3,11,11a‐tetrahydro‐1H,5H‐pyrrolo‐[2,1‐c][1,4]benzothiazepine 10 and 11 have been studied.

The former was obtained by intramolecular cyclization with CDI of N‐(2‐mercaptobenzoyl)‐L‐proline 19, prepared on one hand by demethylation of N‐(2‐methylthiobenzoyl)‐L‐proline t‐butyl ester 15, obtained via the Pummerer rearrangement of the corresponding sulphoxide 17 and successive alkaline hydrolysis, and by deprotection of the mercapto ester 18 with TFA or trimethylsilyl iodide. The ester 15 was achieved by reaction of o‐(methylthio)benzoic acid 12 with L‐proline t‐butyl ester or by treatment of the corresponding acid chloride 13 with L‐proline and successive esterification of N‐(2‐methylthiobenzoyl)‐L‐proline 16. On the other hand the proline 19 was also obtained by reduction with sodium dithionite of (S)‐bis[2‐[[2‐(hydroxycarbonyl)‐1‐pyrrolidinyl]carbonyl]phenyl] disulphide 20, prepared by condensation of bis(2‐chlorocarbonylphenyl) disulphide 14 with L‐proline. The reduction of (S)‐bis[2‐[[2‐(chloromethyl)‐1‐pyrrolidinyl]carbonyl]phenyl] disulphide 28 with sodium borohydride in boiling ethanol afforded directly the benzothiazepinone 11 in 85% yield. The disulphide 28 was synthesized treating the corresponding alcohol 24 or N‐(2‐mercaptoben‐zoyl)‐L‐prolinol 25 with thionyl chloride. Compound 25 was obtained by demethylation of the corresponding methylthio ether 26 oxidized to sulphoxide 27 via the Pummerer rearrangement. The acid chloride 14 by condensation with (S)‐2‐(chloromethyl)pyrrolidine hydrochloride gave disulphide 28 as well. The acid chlorides 13 and 14 by reaction with L‐prolinol provided respectively alcohols 26 and 24.

Attempts to cyclodehydrate the mercapto alcohol 25, obtained also by reduction of disulphide 24, failed.
New benzimidazole synthesis
Authors: Benincori T. , Sannicolò F.
Published: April 2009

Thermal or acid catalyzed cyclization of several N‐(N‐arylbenzimidoyl)‐1,4‐benzoquinoneimines 2 affords 1‐aryl‐6‐hydroxy‐2‐phenylbenzimidazoles 3 in fairly good yields. Structural proofs and kinetic support for the reaction mechanism are given.
A new highly efficient method for the synthesis of trans‐tetrahydro‐3,4‐furandiamine
Authors: Bitha Panayota , Lin Yang‐I
Published: April 2009

A new four‐step, highly efficient synthesis of trans‐tetrahydro‐3,4‐furandiamine is described. Nitromercuration of 2,5‐dihydrofuran with sodium nitrite and mercuric chloride in aqueous solution followed by base catalyzed elimination yielded 3‐nitro‐2,5‐dihydrofuran which was aminated with ammonium hydroxide to give trans‐tetrahydro‐4‐nitro‐3‐furanamine. Catalytic reduction of this material afforded the desired product 5 in 37% overall yield.
A new synthesis of 2,3‐dihydrofuro[2,3‐b], [2,3‐c] and [3,2‐c]quinolines
Authors: Godard A. , Jacquelin J. M. , Queguiner G.
Published: April 2009

A new synthesis of three isomeric dihydrofuroquinolines is described. This route via ortholithiation of O‐quinolyl carbamates is considerably more effective than that which proceeds via lithiation of alkoxyquinolines.
13C NMR studies of substituted 2,3‐diphenylindoles. Methyl and nitro derivatives
Authors: Erra‐Balsells R.
Published: April 2009

The 13C nmr spectra of a series of methyl‐ and/or nitro‐2,3‐diphenylindole derivatives are reported. The dependence of a) 1H and 13C methyl group shieldings on molecular geometry and b) the possibility that 13C nmr might be a useful tool in determining photochemical reactivity are discussed briefly.
New heterocyclic compounds derived from diethyl 2,5‐dioxo‐1,4‐cyclohexanedicarboxylate and 2‐aminobenzophenone
Authors: Kitahara Kiyoshi , Nishi Hisao
Published: April 2009

The synthesis and properties of a new class of heterocyclic compounds 5–8 derived from 2‐aminobenzo‐phenone and diethyl 2,5‐dioxo‐1,4‐cyclohexanedicarboxylate were investigated.
An asymmetric isoxazole annulation
Authors: Marron Brian E. , Schlicksupp Ludwig , Natale N. R.
Published: April 2009

An Asymmetric isoxazole annulation proceeds from the (S)‐O‐methoxyphenylalaninol imine of (RS)‐2‐phen‐ylpropionaldehyde (3). Deprotonation, quenching with 4‐chloromethyl‐3,5‐dimethylisoxazole, and hydrolysis produced isoxazolylaldehyde (5), whose structure was confirmed by single crystal X‐ray diffractometry. The absolute configuration of (‐)‐5 was established as (R)‐by chemical correlation to the known (S)‐(‐)‐4‐methyl‐4‐phenyl‐cyclohex‐2‐ene‐1‐one (7).
A new route to 1,2,4‐ triazoles and 1,3,4‐ thiadiazoles from 1‐acylbithiourea
Authors: Okawara Tadashi , Tateyama Yoshihiro , Yamasaki Tetsuo , Furukawa Mitsuru
Published: April 2009

The intramolecular cyclization of 1‐ acylbithiourea 1 gave 1,2,4‐triazole 2 and 1,3,4‐thiadiazole 3. The reaction of 1 with p‐toluenesulfonyl chloride in the presence of trithylamine afforded 3. Treatment of 1 with methyl iodide in the absence of any base yielded 2‐methylthio‐1,3,4‐thiadiazole 10 and 2‐imino‐ 1,3,4‐thiadiazoline 12.
Hydroxymethylation and aminomethylation of 6‐mercaptopurine and its derivatives
Authors: Siver Kevin G. , Sloan Kenneth B. , Waranis Robert P. , Saab Akram
Published: April 2009

Labile aminomethyl and hydroxymethyl derivatives of 6‐mercaptopurine (I) (6‐MP) and S6‐acyloxymethyl‐6‐MP have been converted to stable acetyloxymethyl derivatives by their reaction with acetic anhydride. Analysis of the reaction products and comparison of their 'H nmr spectra and hplc chromatograms with those of acetyloxymethyl derivatives of known structures suggested 1) that the aminomethyl derivatives of 6‐MP were 7‐substituted derivatives, 2) that the aminomethyl derivative of S6‐acetyloxylmethyl‐6‐MP was a 9‐derivative, 3) that the hydroxymethyl derivative of 6‐MP was a mixture of 7‐substituted and S6,3‐disubstitu‐ted derivatives, and 4) that the hydroxymethyl derivative of S6‐pivaloyloxymethyl‐6‐MP was a 9‐substituted derivative. In addition, a previously unreported dialkyl derivative of 6‐MP VI was isolated from its reaction with aminomethylating agent and characterized. Analyses of the 'H nmr spectra and hplc chromatograms of the reaction of VI with acetic anhydride suggested that VI was a 1,7‐disubstituted derivative.
Acetal formation from formylthiophene‐2‐carboxylic acids and recalculation of σI and σR substituent constants of the acetal group by 13C NMR chemical shifts
Authors: Lamartina Liliana , Noto Renato , Arnone Caterina
Published: April 2009

A uv‐visible, 1H and 13C nmr study has been carried out to show that 4‐, 1, and 5‐formylthiophene‐2‐carboxylic acids, 2, give acetals in methanol. The ms data have confirmed the acetal formation, which has been studied kinetically by the uv technique. The substituent chemical shifts induced on the carboxy carbon atom and on the endocyclic carbon atoms in the acetals formed from 1 and 2 and in the corresponding anions have been used to recalculate σI and σR values by means of a dual substituent parameter treatment of data.
The 2,1‐benzisothiazolo[2,3‐b]‐2,1‐benzisothiazole system, synthesis and properties
Authors: Mckinnon David M. , Duncan K. Ann
Published: April 2009

2,2′‐Diaminodiphenylmethane and its 4,4′‐dibromo‐derivative both react with N‐sulfinylmethanesulfon‐amide to form 2,1‐benzisothiazole derivatives. Methylation or acetylation of these provides examples of the hypervalent sulfur 2,1‐benzisothiazolo[2,3‐b]‐2,1‐benzisothiazole system. The nmr spectra of these compounds are discussed.
1,3‐Dipolar cycloadditions of mesitonitrile oxide with (9‐fluorenylidene)‐aceto‐ and malono‐nitriles. Synthesis of mono‐ and bis‐1,2,4‐oxadiazolylmethane derivatives
Authors: Lianis Pygmalion S. , Rodios Nestor A. , Alexandrou Nicholas E.
Published: April 2009

Mesitonitrile oxide reacts with C ≡ N bond of (aryl)(9‐fluorenylidene)acetonitriles 1 forming in very good yields the corresponding 1,2,4‐oxadiazoles 2. Analogously also proceeds the reaction of mesitonitrile oxide with 9‐fluorenylidenemalonodinitrile (3) with the formation of bis‐1,2,4‐oxadiazole derivative 4.
Reactions of anthranilamide with isocyanates: A new facile synthesis of 2,3‐dihydro‐5H‐oxazolo[2,3‐b]quinazolin‐5‐one and 3,4‐dihydro‐2H,6H‐[1,3]oxazino[2,3‐b]quinazolin‐6‐one [1]
Authors: Chern Ji‐Wang , Shish Fang‐Jy , Chang Chau‐Dung , Chan Chao‐Han , Liu Kang‐Chien
Published: April 2009

2,3‐Dihydro‐5H‐oxazolo[2,3‐b]quinazolin‐5‐one 5a was synthesized from anthranilamide 1 and 2‐chloro‐ethyl isocyanate either by a direct reflux in methanol, or by stirring at room temperature in acetonitrile leading to the intermediate, 2‐(2‐chloroethyl ureido)benzamide 6a which was subsequently cyclized on heating with an organic base. However, when compound 6a was refluxed with concentrated hydrochloric acid, it furnished 3‐(2‐chloroethyl)‐2,4‐dioxo‐1H,3H‐quinazoline 2a in good yields. 3,4‐Dihydro‐2H,6.H‐[1,3]‐oxazino[2,3‐b]quinazolin‐6‐one 5b, 3‐(3‐chloropropyl)‐2,4‐dioxo‐1H,3.H‐quinazoline 2b and 2‐(3‐chloropropyl ureido)benzamide 6b were obtained similarly from 1 and 3‐chloropropyl isocyanate.
The insertion and extrusion of heterosulfur bridges. XV. S‐bridging of 2,2′‐binaphthyl and 1‐(2‐naphthyl)cyclohexene. Studies on hydrodehalogenation during the reaction
Authors: Klemm L. H. , Stevens Michael P. , Iran Long K. , Sheley John
Published: April 2009

Regioselectivity occurs in the sulfur‐bridging reactions of 2,2′‐binaphthyl (1) and 1‐(2‐naphthyl)cyclohexene (7) by means of hydrogen sulfide and a chromia‐alumina‐magnesia catalyst (designated I) in a flow apparatus at 550°. Thus, 1 gives a higher yield (6.1%) of dinaphtho[1,2–6:2′,l'‐d]thiophene from 1,1′‐bridging than of dinaphtho[1,2‐b:2′,3′‐d]thiophene (3.4%) from l,3′‐bridging. No product expected from 3,3′‐bridging was identified. Substrate 7 undergoes both dehydrogenation and bridging to yield 2‐phenylnaphthalene (8%), benzo[b]naphtho[2,1‐d]thiophene (9%) from alpha bridging, and benzo[b]naphtho[2,3‐d]thiophene (3%) from beta bridging into the naphthalene ring.

Exploratory studies showed that either sulfided catalyst I or a sulfided molybdenum(VI) oxide‐alumina‐cobalt(II) oxide catalyst (II) effects hydrodehalogenation of various monohalo‐ and polyhaloarenes (where halo, X, is chloro or bromo) at 450–550°. In the biphenyl, phenanthrene, naphthalene, and pyrene systems, halogen was lost either under sulfur‐bridging conditions or under hydrogenolysis conditions, i.e. with methanol as a reactant. For every substrate the parent arene was isolated or identified as a reaction product. In selected experiments, acid HX was also identified in the effluent. Use of hydrogen sulfide as a reactant led to formation of dibenzothiophene and phenanthro[4,5‐bcd]thiophene as main products in the biphenyl and phenanthrene systems, respectively; while use of methanol as a reactant gave small amounts of methyl bromide (for X = Br) and methylarenes.
Synthesis and reactions of some 6‐(2‐hydroxy‐1‐naphthyl)‐1,2,4‐triazines
Authors: Eid Mohga M. , Kadry Azza M. , Hassan Ramadan A.
Published: April 2009

4,5‐Benzocoumaran‐2,3‐dione condenses with semicarbazide and thiosemicarbazide at the 3‐position and the products obtained were converted to the corresponding 6‐(2‐hydroxy‐1‐naphthyl)‐1,2,4‐triazines. Reactions of these triazines with some reagents are described.
Selective method for the preparation of isomeric N‐alkyl and N‐aryl‐3(5)‐amino‐5(3)‐hydroxy‐1H‐pyrazole‐1‐carboxamides
Authors: Drummond James T. , Johnson Graham
Published: April 2009

As part of a program to develop novel mechanism based skeletal muscle relaxants we identified 5‐amino‐3‐hydroxy‐1H‐pyrazole‐1‐carboxamide (1) as a potential structural lead. This highly functionalized pyrazole was prepared via a published procedure [1] (Scheme 1, R1 = R1 = H), which utilized 3,5‐dimethyl‐1H‐pyrazole‐1‐carboxamide as an aminocarbonyl transfer reagent, to give with cyanoacethydrazide the semicarbazide intermediate 6. Base catalyzed cyclization of 6 afforded the initial lead compound. This reaction scheme was extended to the synthesis of additional 4‐alkyl‐ and 4‐aryl‐5‐amino‐3‐hydroxy‐1H‐pyrazole‐1‐carboxamides (Table 1).
Independent synthesis of 5‐hydroxytryptamine‐4,7‐dione ‐ the neurocytotoxic product of autoxidation of 5,7‐dihydroxytryptamine
Authors: Sinhababu Achintya K. , Borchardt Ronald T.
Published: April 2009

Synthesis of 5‐hydroxytryptamine‐4,7‐dione hydrochloride (20) is described starting from 3‐bromo‐4,5‐dimethoxybenzaldehyde (6). Compound 6 was converted to 2,3,5‐tris(benzyloxy)benzaldehyde (10) in 4 steps. Nitromethylenation of 10 followed by nitration and subsequent reductive cyclization gave 4,5,7‐tris(benzyloxy)indole (13). Introduction of the aminoethyl (hydrochloride) side chain on C‐3 of 13, via the corresponding indole‐3‐acetonitrile, and subsequent debenzylation generated in situ, 4,5,7‐trihydroxytryptamine hydrochloride (19) which underwent rapid autoxidation in ethanol to give 20. 4,5,7‐Trihydroxyindole (21) and 3‐[2‐(ethoxycarbonylamino)ethyl]‐4,5,7‐trihydroxyindole (24), both generated in situ, were also found to undergo rapid autoxidation to the corresponding 5‐hydroxyindole‐4,7‐diones.
Synthesis and structure elucidation of N‐methyl‐4‐(2‐benzo‐γ‐pyronyl)‐1,2,3‐triazoles
Authors: Mouysset G. , Grassy G. , Payard M. , Commenges G. , Carpy A. , Couquelet J.
Published: April 2009

When diazomethane was reacted with 2‐cyano chromones, three isomeric N‐methyltriazoles were obtained. They were isolated by liquid chromatography with three different solvents for elution. Complete elucidation of the structures was performed both by pmr and cmr spectrography; X‐ray analysis is in agreement with the proposed structures.
Cyclic homologs of xanthines.I. Imidazo[4,5‐e][1,4]diazepine‐5,8‐diones
Authors: Bridson Peter K. , Weirich Timothy P.
Published: April 2009

A useful synthetic approach to variously alkylated 4,5,7,8‐tetrahydro‐6.H‐imidazo[4,5‐e][1,4]diazepine‐5,8‐diones is reported. These compounds are potentially interesting cyclic homologs of pharmacologically important alkylxanthines.
Synthesis of 2‐oxo‐3‐benzothiazolineacetyl chloride (7), 5‐chloro‐2‐oxo‐3‐benzothiazolineacetyl chloride (8) and derivatives
Authors: D'Amico John J. , Bollinger Frederick G.
Published: April 2009

The reaction of 2‐oxo‐3‐benzothiazolineacetic acid (5) and the 5‐chloro analogue 6 with thionyl chloride afforded the titled compounds 7 and 8. The reaction of 7 or 8 with substituted hydrazines, amines or substituted anilines, alcohols and mercaptans furnished the hydrazides 9–14, acetamides and acetanilides 16–21, esters 26–30 and thiolesters 31–37, respectively. Alternate routes for the synthesis of hydrazide 15, acetamides and acetanilides 22–25 and thiolesters 35–36 are described. The reaction of 2‐oxo‐3(2H)‐benzothi‐azolineacetonitrile with thioacetic acid under acidic conditions afforded 2‐oxo‐3‐benzothiazolineethanethio‐amide (38).
Synthesis of 1‐aryl‐5‐arylazo‐3‐phenylsulfonylpyrazol‐4‐ols from 1‐bromo‐3‐phenylsulfonyl‐2‐propanone
Authors: Takahashi Masahiko , Abe Hidetoshi , Tetsuka Takashi
Published: April 2009

Treatment of 1‐bromo‐3‐phenylsulfonyl‐2‐propanone (1) with arenediazonium chloride gave 1‐aryl‐5‐arylazo‐3‐phenylsulfonylpyrazol‐4‐ols 5a‐h in 13–48% yields.
Rearrangement reactions of heterocycles. 12. Rearrangement of 6‐substituted pyrido[1,2‐a]pyrimidines to isomeric 1,8‐naphthyridines and some of their further reactions
Authors: Schober Bernt D. , Kappe Thomas
Published: April 2009

2‐Amino‐6‐methylpyridine (4) reacts with active malonates 2a‐d or 3a‐d either in acetone solution with triethylamine as catalyst at room temperature or with active malonates 2a‐d in acetone solution at reflux temperature to yield the pyrido[1,2‐a]pyrimidines 5a‐d. 2,6‐Diaminopyridine (8) already reacts without triethylamine with 2a‐d at room temperature to afford the pyrido[1,2‐a]pyrimidines 9a‐d. At higher temperatures pyrido[1,2‐a]pyrimidines 5 and 9 are rearranged via ketene intermediates [1] to yield the 1,8‐naphthyridines 6a‐d, and 10a‐d, respectively. The naphthyridines 6 and 10 can also be synthesized directly from 4 or 8 using either diethyl malonates 1 or — with better results — the active malonates 2 at 240–250°. Further reaction of 10a‐e with 2c,d leads to the pyridonaphthyridines 12a‐f. Nitration of 6c yields the nitro derivative 16 and chlorination of 6c,d gives 15c,d, while the chlorination of 10c affords the di‐chloro derivative 17.
Photochemistry of ommochrome pigments
Authors: Bolognese Adele , Liberatore Rosa
Published: April 2009

The ommochrome pigment present in the eyes of Loligo Vulgaris was extracted with a butanol‐acetic acid‐hydrochloric acid solution. The extraction mixture was examined before and after irradiation by visible light. A phenoxazinone ring opening together with a photo‐induced solvent addition, causing a yellow‐red batho‐chromic shift, were observed and a plausible explanation of the process has been carried out and is reported on the basis of the isolated products.