bluuebunny/crossref_metadata_2025_split huggingface dataset:
The gomberg‐bachmann reaction of purines
Authors: Mckenzie Thomas C. , Rolfes Steven M. 
Published: April 2009

AbstractThe reaction of adenine derivatives with isoamyl nitrite in anisole solution was re‐investigated. The arylated products are a mixture of ortho, meta, and para‐methoxyphenyl isomers with the ortho predominating. It is concluded that this is a typical free‐radical arylation and that the 6‐purinyl radical is a normal, well behaved aromatic radical.
Electron impact mass spectrometry of polyannulated oxygen heterocycles with cyclic orthoester or acetal moieties
Authors: Bravo Pierfrancesco , Ticozzi Calimero , Maccioni Anna Maria , Traldi Piero 
Published: April 2009

AbstractThe mass spectrometric behaviour of the pairs of diastereoisomeric 3‐methyl‐ and 3‐phenyl‐substituted 3,11b‐epoxy‐2,3,4,5,5a,11b‐hexahydro‐5a‐hydroxyoxepino[3,2‐c][1]benzopyran‐6‐ones 5,6 and 7,8 and the pairs of diastereoisomeric 3‐methyl and 3‐phenyl substituted 3,11a‐epoxy‐2,3,4,5,5a,11a‐hexahydro‐5a‐hydroxyoxepino[2,3‐b][1]benzopyran‐6‐ones 9,10 and 11,12 has been studied in detail with the aid of exact mass measurements, B/E linked scans, collisional experiments and deuterium labelling. Characteristic ionic species for angularly annulated compounds 5‐8 and for linearly annulated ones 9‐12 have been found, thus allowing the structural assignment. No differences could be determined in the fragmentation patterns of the diastereoisomeric compounds.
Synthèse, à partir du (+) — camphre, d'hétérocycles dérives des tétrahydroxanthone, tétrahydroacridone, tétrahydroacridine et octahydroacridine
Authors: Sotiropoulos Jean , El Batouti Nagui , Lamazouère Anne‐Marie 
Published: April 2009

AbstractCertaines arylidène‐3, arylméthyl‐3 et aroyl‐3 bornanones‐2, convenablement substitutés dans le noyau aromatique, et des dibornanonylarylméthanes peuvent subir une hétérocyclisation avec de bons rendements sous l'action de l'ammoniac ou des amines ou de la potasse, en présence ou non de catalyseurs, pour conduire à des dérivés de la tétrahydroxanthone, de la tétrahydro ou octahydroacridine et de la tétrahydroacridone. Dans certains cas, la cyclisation est accompagnée d'aromatisation.
Improved syntheses of 6‐hydroxy‐5‐methoxy‐ and 5‐hydroxy‐6‐methoxyindoles and their O‐acetates, analogs of natural eumelanin precursors
Authors: Rogers C. Bradford , Blum Charles A. , Murphy Bryan P. 
Published: April 2009

AbstractImproved routes for syntheses of gram quantities of the isomeric 5,6‐acetoxymethoxyindoles, and milligram amounts of the 5,6‐hydroxymethoxyindoles, have been developed. They depend on regiospecific nitration of the benzyl ethers of vanillin and isovanillin as the first steps. Improved condensations of 4,5‐acetoxymethoxy‐2‐nitrobenzaldehydes with nitromethane gave 4,5‐acetoxymethoxy‐2,β‐dinitrostyrenes as the key intermediates to all four indoles.
Polycyclic N‐hetero compounds. XXII Reaction of pyridine N‐oxides and Pyrazine di‐N‐oxides with formamide
Authors: Hirota Takashi , Namba Tetsuto , Sasaki Kenji 
Published: April 2009

AbstractReactions of pyridine N‐oxides, pyrazine di‐N‐oxides, and their benzologues with formamide are described. Carbamoylation mainly occurred at aromatic ring with loss of the N‐oxide oxygen atom, however, 2,4,6‐trimethylpyridine 1‐oxide gave 2‐ and 4‐pyrimidinyl derivatives.
Diazapolycyclic compounds. XXVII. On the selective hydrogenation of benzo[g]phthalazine‐1,4‐dione and 5‐methoxybenzo[g]phthalazine‐1,4‐dione adducts
Authors: Campayo L. , Navarro P. , Contreras F. Gómez 
Published: April 2009

AbstractA number of diazapolycyclic structures obtained by cycloaddition reaction of benzo[g]phthalazine‐1,4‐dione with several 1,3‐dienes have been catalytically hydrogenated on palladium over charcoal. In a first step the double bond formed in the cycloaddition was reduced, except in the case of tetrasubstitution. The use of longer reaction times led to the selective reduction of the terminal aromatic rings, although the presence of the 5‐methoxy substituent favored tetrahydropyridazine ring opening and prevented aromatic ring reduction. The stereochemical features of new compounds obtained are commented on the basis of X‐ray and nmr data.
Synthesis of aminomethyl and amino analogs of 5‐benzylacyclouridine and 5‐benzyloxybenzylacyclouridine
Authors: Chu Shih Hsi , Chen Zhi Hao , Weng Zun Yao , Rowe Elizabeth C. , Chu Edward , Chu Ming‐Yu Wang 
Published: April 2009

AbstractAmino analogs of BAU (5‐benzylacyclouridine) and BBAU (5‐benzyloxybenzylacyclouridine) and their 2′‐hydroxymethyl derivatives were synthesized for evaluation as inhibitors of uridine phosphorylase and hence potential cancer chemotherapeutic agents. Both aminomethyl analogs were found to be potent inhibitors of this enzyme and good potentiators of the anti‐tumor action of FUdR.
“One pot” synthesis of 2,9‐disubstituted 8‐azaadenines (3,5‐disubstituted 7‐amino‐3H‐1,2,3‐triazolo[4,5‐d]pyrimidines)
Authors: Barili Pier Luigi , Biagi Giuliana , Livi Oreste , Mucci Luciana , Scartoni Valerio 
Published: April 2009

AbstractA new simple method for the synthesis of title compounds is described starting from malononitrile, benzyl‐azide and an aliphatic or aromatic nitrile.
Synthesis of antimicrobial agents. II. Syntheses and antibacterial activities of optically active 7‐(3‐hydroxypyrrolidin‐1‐yl)quinolones
Authors: Uno Toshio , Iuch Koji , Kawahata Yoshihiro , Tsukamoto Goro 
Published: April 2009

AbstractTwo optically active isomers of 1‐ethyl‐6,8‐difluoro‐1,4‐dihydro‐7‐(3‐hydroxypyrrolidin‐1‐yl)‐4‐oxoquinoline‐3‐carboxylic acid (10) were prepared. One of the isomer, 7‐[(3S)‐hydroxypyrrolidin‐1‐yl] derivative 8, was about 4 times more potent in vitro than the other, 7‐[(3R)‐hydroxypyrrolidin‐1‐yl] derivative 4, and approximately two times more active than the racemate, 7‐[(3RS)‐hydroxypyrrolidine‐1‐yl] derivative 10.Optical active 8 was the most active in in vivo, followed by 10, and 4 was the least active compound. But, they were more potent than CI‐934 12 and norfloxacin.From the results, (3S)‐hydroxypyrrolidinyl group was found to be one of the beneficial group for PCA‐anti‐bacterial agent.
A new synthesis of aryl hetaryl ketones via SRN1 reactions of halogenated heterocycles with potassiophenylacetonitrile followed by phase‐transfer catalyzed decyanation
Authors: Hermann Christine K. F. , Sachdeva Yesh P. , Wolfe James F. 
Published: April 2009

AbstractReaction of halogenated pyridines, quinolines, pyrimidines, and pyrazines with potassiophenylacetonitrile (5) in liquid ammonia under near‐uv irradiation affords secondary nitriles, which then undergo oxidative decyanation under phase‐transfer catalytic conditions to afford aryl hetaryl ketones in excellent yields.
The proton and carbon‐13 NMR spectra of thioxanthone sulfoxide, thioxanthone sulfone and related ylides ‐ chemical shift assignments
Authors: Ternay A. L. , Cushman J. A. , Harwood J. S. , Yu C. P. 
Published: April 2009

AbstractThe proton and carbon‐13 nmr spectra of thioxanthone sulfoxide, thioxanthone sulfone, thioxanthonium bis(carbomethoxyl)methylide and thioxanthonium bis(carbomethoxyl)methylide S‐oxide are assigned using 2‐D nmr techniques and compared to those of thioxanthone. The pseudo‐equatorial methylide fragment shields C4a/5a by ˜ 11 ppm relative to the corresponding sulfoxide and by ˜ 4 ppm relative to thioxanthone. The pseudo‐axial methylide fragment in the oxysulfonium ylide has the same effect upon C4a/5a as does the pseudo‐axial oxygen of the corresponding sulfone. The sulfoxide and the sulfonium ylide have similar chemical shifts for C2/7 (˜ 131 ppm) as do the sulfone and oxysulfonium ylide (˜ 133 ppm).
Proton‐ionizable crown compounds. 10. Preparation and structural studies of macrocyclic ligands containing two sulfonamide units and with seventeen to twenty‐six ring members
Authors: Bradshaw Jerald S. , Koyama Hiroyuki , Dalley N. Kent , Izatt Reed M. , Biernat Jan F. , Bochenska Maria 
Published: April 2009

AbstractEight new macrocylic ligands each containing two sulfonamide groups have been prepared. Six of these compounds have both the sulfur and nitrogen atoms of the sulfonamide units substituted with aromatic rings. The nitrogen atoms of the other two compounds have alkyl ring connections. X‐ray crystal structure data were obtained for new macrocyclic compounds of 20 and 23 ring members. Each crystal structure showed two molecules in the asymmetric unit. Molecule A of 5 and both molecules of 7 exist in a compact conformation suggesting that they could wrap around a metal ion during complexation. Some of these compounds will be used as cation carriers in a bulk liquid membrane system.
Synthesis of 3‐alkyl‐6‐phenyl‐4(3H)‐pteridinones and their 8‐oxides. Potential substrates of xanthine oxidase
Authors: De Meester J. W. G. , Kraus W. , Van Der Plas H. C. , Brons H. J. , Middelhoven W. J. 
Published: April 2009

AbstractSynthetic routes for the preparation of 3‐alkyl‐6‐phenyl‐4(3H)‐pteridinones 6 and their corresponding 8‐oxides 5 (R = CH3, C2H5, (CH2)2CH3, (CH2)3CH3, CH(CH3)C2H5, CH(CH3)2 and CH(C2H5)CH2OCH(OC2H5)2 are described and their reactivities towards xanthine oxidase from Arthrobacter M‐4 are determined. Only the 3‐methyl derivative of 6‐phenyl‐4(3H)‐pteridinone and its 8‐oxide i. e. 6a and 5a are found to be substrates although their reactivities are still very low. Oxidation takes place at C‐2 of the pteridinone nucleus. All the 3‐alkyl derivatives are less tightly bound to the enzyme than 6‐phenyl‐4(3H)‐pteridinone. Introduction of the N‐oxide at N‐8 considerably lowers the binding of the substrates. Inhibition studies have revealed that 3‐methyl‐6‐phenyl‐4(3H)‐pteridinone (6a) is a non‐competitive inhibitor with a Ki‐value of 47 μM and the 3‐ethyl derivative (6b) an uncompetitive one with a Ki‐value of 19.6 μM.
[2 + 2] Cycloaddition reactions of unsymmetrically substituted carbodiimides
Authors: Ulrich Henri , Richter Reinhard , Tucker Benjamin 
Published: April 2009

AbstractN‐Alkyl‐N′‐arylcarbodiimides add alkyl and aryl isocyanates to the N‐alkyl substituted CN double bond to yield 4‐arylimino‐1,3‐diazetidine‐2‐ones 3. In the case of bulky alkyl substituents the reaction still proceeds across the sterically hindered CN double bond. N‐Aryl‐N′‐[(4‐dimethylamino)phenyl]carbodiimides form [2 + 2] cycloadducts with aryl isocyanates preferentially across the CN double bond not attached to the electron‐rich aryl groups. However, steric crowding on this CN double bond directs the reaction to the adjacent double bond of the heterocumulative system. The rate of the [2 + 2] cycloaddition reaction of N'‐methyl‐N′‐phenylcarbodiimide with 4‐nitrophenylisocyanate is about 2.5 times faster in acetonitrile than in benzene.
The synthesis of methyl 1‐aryl‐2‐pyrrolecarboxylates
Authors: Kiely John S. , Huang Suchin 
Published: April 2009

AbstractA series of alkyl 1‐(aryl)‐2‐pyrrolecarboxylates were prepared by the condensation of the appropriate aniline with methyl tetrahydro‐2,5‐dimethoxy‐2‐furancarboxylate in refluxing acetic acid. It was found that condensation proceeds even in substituents possessing steric bulk are present in the ortho positions of the aniline. Strong electron withdrawing substituents if conjugated to the nitrogen diverts the reaction from product to unidentified tars.
Heterocycles. Part XII. Synthesis of new benzo[6,7]cyclohepta[1,2‐d]pyrimidine
Authors: El‐Rayyes N. R. , Ramadan H. M. 
Published: April 2009

AbstractSelected 2‐arylidene‐1‐benzosuberones I were condensed with guanidine hydrochloride to give the corresponding substituted 2‐aminopyrimidines II and III respectively. Condensation of chalcones I with benz‐amidine hydrochloride revealed the formation of the corresponding substituted 2‐phenylpyrimidines IV. The structure of all products was substantiated by chemical and spectroscopic methods.
On triazoles. VIII The reaction of 5‐amino‐1,2,4‐triazoles with ethyl 2‐cyano‐3‐ethoxyacrylate and 2‐cyano‐3‐ethoxyacrylonitrile
Authors: Reiter József , Pongó László , Dvortsák Péter 
Published: April 2009

AbstractThe reaction of different 5‐amino‐3‐Q‐1H‐1,2,4‐triazoles 1 with ethyl 2‐cyano‐3‐ethoxyacrylate (5a) and 2‐cyano‐3‐ethoxyacrylonitrile (5b) to yield either the a type 5‐amino‐, or the b type 7‐amino‐1,2,4‐triazolo[1,5‐a]‐pyrimidine derivatives 6–10 was studied. The structure of compounds 6 and 9 was proved by their degradation to the corresponding derivatives 17a and 18a, respectively, through intermediates 11a, 12a, 13a, 14a, 15a and 16a, respectively. The structure of derivatives 7, 8 and 10 was proved on the basis of the analogy of their uv spectra with those of 6a and 9a, respectively. The isolation of the intermediates 19 and 20 helped to prove the mechanism of the reactions leading to the formation of 6a and 9a, respectively. In the reaction of the N‐substituted 5‐amino‐1,2,4‐triazoles with 5a the expected condensed ring products were not formed. Instead the aminoacrylates 22 and 24 were obtained. The “Z”‐“E” isomeric structure of derivatives 19, 20, 22 and 24 was proved with the help of their pmr spectra. The “Z” isomeric structure of the thermodynamically stabile 22 was corroborated with the help of its proton coupled cmr spectra, too.
Intramolecular cyclization of ethyl ω‐(5‐amino‐4‐aminocarbonylimidazol‐1‐yl)carboxylates
Authors: Bridson P. K. , McGowan A. , Wilson C. M. , Yeh Y. M. 
Published: April 2009

AbstractAttempted elaboration of the title compounds to purines by reaction with ethyl formate leads instead to some novel fused imidazoles by intramolecular cyclization.
Nitrogen‐15 studies of the mechanisms of acetolyses of hexamethylenetetramine and 3,7‐diacetyl‐1,3,5,7‐tetraazabicyclo[3.3.1]nonane (DAPT)
Authors: Cooney Aidan P. , Crampton Michael R. , Jones Michael , Golding Peter 
Published: April 2009

Abstract[15N4]‐Hexamethylenetetramine (Hexamine), and [15N4]‐3,7‐diacetyl‐1,3,5,7‐tetraazabicyclo[3.3.1]nonane(DAPT) have been prepared starting from 15NH3. Synthetic acetolysis reactions were performed using mixtures of pure [15N4]‐ and [14N4]‐compounds and the destination of the nitrogen isotopes in the products was determined mass spectrometrically. The results show that relatively little isotopic mixing occurs in the acetolysis of hexamine to DAPT though the formation of some products with isotopic composition [14N315N1] and [14N115N3] indicates limited ring cleavage. However the more severe conditions used in the formation of 1,3,5‐triacetyl‐1,3,5‐triazacyclohexane (TRAT) give rise to considerable isotopic scrambling. The acetolysis of DAPT to give 1,3,5,7‐tetraacetyl‐1,3,5,7‐tetraazacyclooctane occurs by selective cleavage of the methylene bridge.
Synthesis of heterocycles. Part VII Synthesis and antimicrobial activity of some 7H‐s‐triazolo[3,4‐b][1,3,4]thiadiazine and s‐triazolo[3,4‐b][1,3,4]thiadiazole derivatives
Authors: Eweiss N. F. , Bahajaj A. A. 
Published: April 2009

AbstractThe cyclization of 4‐amino‐5‐aryl‐3‐cyanomethylthio‐1,2,4‐triazoles II in the presence of concentrated sulfuric acid yields 7H‐6‐amino‐s‐triazolo[3,4‐b][1,3,4]thiadiazines III. Cyclization of 4‐amino‐5‐aryl‐1,2,4‐tria‐zole‐3‐thiones I with phenacyl chloride yields 7H‐3‐aryl‐6‐phenyl‐s‐triazolo[3,4‐b][1,3,4]thiadiazines IV. Similarly, compounds I condensed with cyanogen bromide, phenyl isothiocyanate and carbon disulfide to give the corresponding cyclized products 6‐amino‐3‐aryl‐s‐triazolo[3,4‐b][1,3,4]thiadiazoles V, 3‐aryl‐6‐phenyl‐amino‐s‐triazolo[3,4‐b][1,3,4]thiadiazoles VI and 3‐aryl‐striazolo[3,4‐b][1,3,4]thiadiazol‐6(5H)thiones VII, respectively. Also in the presence of phosphoryl chloride, compounds I underwent cyclization with monocarbo‐xylic acids and oxalic acid to 3,6‐diaryl‐s‐triazolo[3,4‐b][1,3,4]thiadiazole VIII and 6,6′‐bis(3‐aryl‐s‐triazolo‐[3,4‐b][1,3,4]thiadiazoles) IX. The above compounds were screened for their antimicrobial activity.
Heterocyclic systems. VII Synthesis of 1H‐pyrazolo[3,4‐e]indolizine derivatives
Authors: Stefancich Giorgio , Corelli Federico , Massa Silvio , Silvestri Romano , Di Santo Roberto 
Published: April 2009

AbstractSuitable 1‐phenyl‐5‐(1‐pyrryl)pyrazole intermediates underwent Knoevenagel or Wittig intramolecular olefination to give derivatives of 1H‐pyrazolo[3,4‐e]indolizine, a hitertho unknown tricyclic heteroaromatic system.
Reaction of hydrazonyl chlorides and carboalkoxymethylene triphenylphosphoranes to give 5‐alkoxy substituted pyrazoles
Authors: Padwa Albert , MacDonald J. Gavin 
Published: April 2009

AbstractThe reaction of ethyl chloroglyoxylate phenyl hydrazone and diphenyl hydrazonyl chloride with several carboalkoxymethylene triphenylphosphoranes has been examined. The products isolated correspond to N‐phenyl‐3‐carboalkoxy‐5‐alkoxy substituted pyrazoles. The mechanism advanced to account for the formation of the products involves the stepwise addition of a nitrile imine intermediate with the Wittig reagent.
Thermal ring transformation of 5‐aryl‐2‐carbazoyl‐1,2,3,4‐tetrazole derivatives
Authors: Milcent René , Barbier Géo 
Published: April 2009

AbstractUnstable 5‐aryl‐2‐(3‐benzylidene‐2‐phenylcarbazoyl)‐1,2,3,4‐tetrazoles 8 have been prepared. By thermal ring transformation, they gave 5‐aryl‐2‐(2‐benzylidene‐1‐phenylhydrazino)‐1,3,4‐oxadiazoles 9., Hydrazinolysis of 9 afforded 5‐aryl‐2‐(1‐phenylhydrazino)‐1,3,4‐oxadiazoles 10. Elimination of a molecule of benzonitrile from 9 on heating converted them into 2‐anilino‐5‐aryl‐1,3,4‐oxadiazoles 11.
Reaction of 5‐(substituted‐amino)oxazoles with N‐phenylmaleimide
Authors: Shimada Sadakatsu 
Published: April 2009

AbstractReaction of 5‐aminooxazoles with N‐phenylmaleimide gave 7‐hydroxy‐2‐phenylpyrrolo[3,4‐c]pyridine‐1,3‐diones and 7‐amino‐2‐phenylpyrrolo[3,4‐c]pyridine‐1,3‐diones via tricyclic adducts. The ratio of the 7‐hydroxy compound and 7‐amino compound depended on the basicity of the leaving group of the adducts. The reaction of 5‐acetaminooxazole with dienophiles is described.
Pyrimidines. 9. Chlorination of 6‐trifluoromethyluracil with phosphorus oxychloride in the presence of trialkylamines
Authors: Gershon Herman , Grefig Anthony T. , Clarke Donald D. 
Published: April 2009

AbstractRing‐chlorination of 6‐trifluoromethyluracil in phosphorus oxychloride in the presence of triethyl, tri‐n‐propyl, and tri‐n‐butylamines was studied with respect to by‐product formation. Comparisons were made with the results obtained by treating the preformed chlorinated pyrimidine with triethyl amine in boiling toluene.Amination of chloropyrimidines by tertiary amines takes place by a Hofmann type reaction with substituent orientation generally in the 2 position of the ring. Yields of products depended on the base and reaction time. The rate of substitution in the 2 position is significantly enhanced by the presence of the trifluoromethyl group in the 6 position as compared with a methyl group.Heating preformed chloropyrimidines with tertiary amines in toluene, offers a satisfactory approach for the preparation of 2‐N,N‐disubstituted aminopyrimidines. For the formation of ring‐chlorinated pyrimidines in phosphorus oxychloride with a minimum of by‐products, tri‐n‐propylamine, after a short reflux period is most useful.
Streptonigrin and lavendamycin partial structures. Preparation of 7‐amino‐2‐(2′‐pyridyl)quinoline‐5,8‐quinone‐6′‐carboxylic acid: A probe for the minimum, potent pharmacophore of the naturally occurring antitumor‐antibiotics
Authors: Yasuda Masami , Boger Dale L. 
Published: April 2009

AbstractThe preparation of 7‐amino‐2‐(2′‐pyridyl)quinoline‐5,8‐quinone‐6′‐carboxylic acid(4)constituting a potential minimum, potent pharmacophore of streptonigrin(1)and lavendamycin(2), two structurally‐related naturally‐occurring antitumor‐antibiotic, is detailed. In contrast to observations associated with streptonigrin and lavendamycin in which the C‐6′ acidpotentiatesthe antitumor, antimicrobial, and cytotoxic activity of the naturally‐occurring, substituted 7‐aminoquinoline‐5,8‐quinone AB ring systems, the C‐6′ carboxylic acid of 4diminishesthe observed antimicrobial and cytotoxic properties of 7‐amino‐2‐(2′‐pyridyl)quinoline‐5,8‐quinone.
Ring closures with α‐chloroazines
Authors: Pilgram Kurt H. , Skiles Richard D. 
Published: April 2009

AbstractTwo series of unsymmetrical 3,6‐disubstituted 1,2,3,4‐tetrahydro‐1,2,4,5‐tetrazines and 3,5‐disubstituted 4‐amino‐2,3‐dihydro‐1,2,4‐triazoles were synthesized from unsymmetrical 1,4‐disubstituted 1‐chloroazines with hydrazine, 1‐methylhydrazine, and 1,2‐dimethylhydrazine. These partially reduced heterocycles belong to little known and less accessible classes of heterocycles.
Oxamic acid derivaties in heterocyclic synthesis: Preparation of 1,2,4‐triazolo[1,5‐a]pyrazine derivatives
Authors: Molina P. , Vilaplana Ma. J. , Andreu P. L. , Møller J. 
Published: April 2009

AbstractN‐Aryl‐N‐(α‐phenylphenacyl)oxamoyl chlorides react with N3‐arylsubstituted amidrazones to give functionalized 1,2,4‐triazoles which undergo ring‐closure by the action of thionyl chloride to give 1,2,4‐triazolo[1,5‐a]‐pyrazinium chlorides in excellent yields.
New syntheses of polyaza derivatives. Crystal structure of pyridazine‐3,6‐dicarboxylic acid
Authors: Sueur Stéphane , Lagrenee Michel , Abraham Francis , Bremard Claude 
Published: April 2009

AbstractA new route allowing the synthesis of pyridazine‐3,6‐dicarboxylic acid in preparative quantities is described. The crystal structure of this compound is reported. Several polyaza derivatives were prepared and their structures determined by specroscopic methods (ir, 1H and 13C nmr).
Synthesis of the 1,2,3,4‐tetrahydrobenzofuro[2,3‐c]pyridine ring system
Authors: Jaen Juan C. , Wise Lawrence D. 
Published: April 2009

AbstractAs part of an on‐going research project, we required an efficient method for the preparation of compounds containing the 1,2,3,4‐tetrahydrobenzofuro[2,3‐c]pyridine ring nucleus. The parent compound 1 has not been described in the literature, and there is only one reference to the N‐methyl analog 2 [1]. A series of structurally related compounds, the 2‐substituted‐4‐hydroxy‐1,2,3,4‐tetrahydrobenzofuro[2,3‐c]pyridines, has been described [2].
Synthesis of 4‐methylthio‐2(1H)‐pyridone derivatives using ketene dithioacetals
Authors: Tominaga Yoshinori , Kawabe Masanori , Hosomi Akira 
Published: April 2009

AbstractReaction of various active methylene compounds with ketene dithioacetals, bis(methylthio)methylenemalononitrile (1a) and bis(methylthio)methylenecyanoacetamide (1b) gave the corresponding 3‐cyano‐4‐methylthio‐2(1H)‐pyridone derivatives. The transformation of 4‐methylthio‐2‐oxo‐2H‐pyran‐3‐carbonitrile in‐to 4‐methylthio‐2(1H)‐pyridone derivatives was also described.
Novel heterocyclic systems. Part 27. The synthesis of various diazathianthrenes and the discrimination of isomeric structures using 13C‐NMR and lanthanide induced shift data
Authors: Lindsay Charles M. , Smith Keith , Martin Gary E. 
Published: April 2009

AbstractSyntheses of the previously unknown 1,7‐1,8‐ and 1,9‐diazathianthrenes are reported. The former two systems were prepared via the condensation of the dianion of 2,3‐dimercaptopyridine with 3‐chloro‐4‐nitropyridine 1‐oxide while the latter employed 2‐chloro‐3‐nitropyridine. The preparation of the 1,9‐diazathianthrene also led to the formation of the previously reported 1,6‐diazathianthrene as a by‐product in a 22% yield. The new ring systems were characterized by a combination of 13C nmr and 1H lanthanide‐induced shifts using Eu(fod)3.