bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of macrocyclic thioether‐diester compounds of fourteen‐seventeen ring members
Authors: Bradshaw Jerald S. , Campbell Mark L. , Hassell Lewis A. , Baxter Jae K. 
Published: April 2009

AbstractA series of macrocyclic thioether diester compounds of fourteen‐seventeen‐membered rings have been prepared from oxalyl, malonyl, substituted malonyl, succinyl, and substituted succinyl, chlorides and various dithiaglycols (compounds 1–12). A twelve‐membered macrocyclic thioetherdithiolester (compound 13) was also prepared from thiadiglycolyl chloride and 2‐mercaptoethyl sulfide.
[1] Benzofuro[2,3‐d] pyridazines. V. Etude de l'oxo‐4 tetrahydro‐1,2,3,4[1] benzofuro[2,3‐d] pyridazine
Authors: De Sévricourt Michel Cugnon , Godard Anne‐Marie , Robba Max 
Published: April 2009

AbstractEngagée dans des réactions de substitution électrophile, l'oxo‐4 tétrahydro‐1,2,3,4[1]benzofuro[2,3‐d]pyridazine (1) conduit à des tétrahydrobenzofuropyridazones monosubstituées (sur N2) ou disubstituées (sur N2 et N3). Les structures des dérivés obtenus sont déterminées par l'étude des spectres ir et de rmn ainsi qu'au moyen de synthèses univoques.
Mononuclear heterocyclic rearrangements. Part 12. Rearrangement of 1,2,4‐oxadiazoles into indazoles
Authors: Vivona Nicolò , Cusmano Giuseppe , Macaluso Gabriella , Frenna Vincenzo , Ruccia Michele 
Published: April 2009

AbstractThe first example of a mononuclear heterocyclic rearrangement involving an XYZ = CCN side‐chain sequence is reported. The 3‐(o‐aminophenyl)‐, and 3‐(o‐methylaminophenyl)‐5‐methyl‐1,2,4‐oxadiazoles (3a,b) gave a thermally induced rearrangement into 3‐acylaminoindazoles (4a,b). On the other hand, the 3‐(o‐acetylaminophenyl)‐5‐methyl‐1,2,4‐oxadiazole (3c) produced a base induced rearrangement into 3‐acetylaminoindazole (4a).
Synthesis of 4H‐furo[3,2‐b]indole derivatives. III. Preparation of 4H‐furo[3,2‐b]indole‐2‐carboxylic acid derivatives
Authors: Tanaka Akira , Yakushijin Kenichi , Yoshina Shigetaka 
Published: April 2009

AbstractMethyl or ethyl 4H‐furo[3,2‐b]indole‐2‐carboxylates (Va,b) were prepared from deoxygenation of methyl or ethyl 5‐(2‐nitrophenyl)‐2‐furoates (IIIa,b) and thermolysis of methyl or ethyl 5‐(2‐azidophenyl)‐2‐furoates (VIIIa,b). 4H‐Furo[3,2‐b]indole‐2‐carboxylic acid amides (XIa‐h) were obtained by the reaction of 4H‐furo[3,2‐b]indole‐2‐carboxyl chloride (X) with the appropriate amines.
Ammonolysis of 3‐hydroxypicolinic acids. A correction and illustration of the use of 13C Nmr OH/OD isotope shifts
Authors: Moore George G. I. , Kirk Alan R. , Newmark Richard A. 
Published: April 2009

AbstractAmmonolysis of 3‐hydroxy‐6‐methylpicolinic acid (1a) has been reported to give 3‐amino‐6‐methylpicolinic acid. However, on heating 3‐hydroxypicolinic acid with ammonia at 200°, the product proved to be the known 3‐hydroxypicolinamide. 13C Nmr OH/OD isotope shifts in DMSO show that ammonolysis of 1a gives not 2a, but instead 3‐hydroxy‐6‐methylpicolinamide.
Central nervous system depressants. 15. 1,4‐benzodiazepines
Authors: Moffett Robert Bruce , Kamdar Bharat V. 
Published: April 2009

AbstractA number of 5‐phenyl‐1,4‐benzodiazepines and a few 2‐phenyl‐1,4‐benzodiazepines were prepared and screened for central nervous system activity in mice. Some were highly active. An unusual substitution of 7‐chloro‐1,3‐dihydro‐5‐phenyl‐2H‐1,4‐benzodiazepin‐2‐one by trichloro‐acetylisocyante is reported.
An anomalous by‐product in the von pechmann reaction
Authors: Belletire J. L. , Donahue K. , Kellogg M. 
Published: April 2009

AbstractDuring condensation of 4‐chloro‐2‐methylphenol with diethyloxalacetate in sulfuric acid the spirodilactone 3 was observed as well as the desired coumarin 1. Further reaction of 1 under the reaction conditions with 4‐chloro‐2‐methylphenol did not produce 3 readily. These observations imply the formation of the intermediate 10 prior to production of the novel spirodilactone 3.
New synthesis of condensed hydropyridazine derivatives. VI
Authors: Plescia Salvatore , Daidone Giuseppe , Sprio Vincenzo 
Published: April 2009

AbstractThe reactivity of some indole derivatives towards the semicarbazone of ω‐bromoacetophenone has been reported. Substituents at position 1 and 2 of the indole ring greatly affect the course of the reaction. 1,4,4a,9a‐Tetrahydro‐9H‐pyridazino[3,4‐b]indole derivatives or 3‐indolyl derivatives were obtained depending on the substituents. The structures were assigned on the basis of satisfactory analytical and spectroscopic data.
Synthesis and properties of alkylated imidazoles
Authors: Huang Bao Shan , Lauzon Mary Jane , Parham James C. 
Published: April 2009

AbstractAlkylation of 4(5)‐nitroimidazole‐5(4)‐sulfonamide with benzyl bromide occurred on both ring nitrogens. The structures of the products could be assigned by comparison of the chemical shifts of the sulfonamide hydrogens in the nmr spectra with those of the isomeric methyl derivatives, which were prepared by differing routes. Uv and nmr spectral data are reported for a number of bromo‐, nitro‐, mercapto‐, sulfamyl‐ and amino‐ substituted imidazoles as well as for both of the isomeric methylated derivatives of the series.
Reactions of β‐heteroatom substituted α,β‐unsaturated ketones with dimethylsulfonium methylide
Authors: Nishio Takehiko , Sugawara Mitsuko , Omote Yoshimori 
Published: April 2009

Abstractβ‐Alkoxy‐ and β‐alkylthio α,β‐unsaturated ketones react with dimethylsulfonium methylide (DMSM) to give a furan, while β‐anilino α,β‐unsaturated ketones give the pyrrole. β,β‐Bis(alkylthio) α,β‐unsaturated ketones react with DMSM to afford the methylene inserted products, λ,λ‐bis(alkylthio) β,λ‐unsaturated ketones.
New synthesis of some 1,2,5‐benzothiadiazcpinc 1,1‐dioxide derivatives. I
Authors: Migliara Onofrio , Petruso Salvatore , Sprio Vincenzo 
Published: April 2009

Abstract2‐Nitrobenzenesulfonyl chloride reacts with ω‐aminoacetophenone and 4‐amino‐3,5‐dimethyl‐isoxazole to give 3 and 7, respectively. Reduction of 3 with zinc powder and acetic acid afforded the 2,5‐dihydro‐ and 2,3,4,5‐tetrahydro‐1,2,5‐benzothiadiazepine I,1‐dioxide derivatives (4 and 5). Catalytic hydrogenolysis of 7 and successive cyclization of the intermediate 8 gave the 3‐ace‐thyl‐2,5‐dihydro‐4‐methyl‐1,2,5‐benzothiadiazepine 1,1‐dioxide (9). The structures were assigned on the basis of correct elemental data and spectroscopic evidences.
Synthesis of 1,2‐dihydroindolo [1,7‐AB] [1,5] benzodiazepines and related structures. A new heterocyclic ring system
Authors: Glamkowski Edward J. , Fortunato James M. 
Published: April 2009

AbstractThe synthesis of the novel 1,2‐dihydroindolo [1,7‐ab][1,5]benzodiazepine ring system 4 is described. Condensation of 2‐fluoronitrobenzene with indoline provided the starting material for the synthesis, 1‐(2‐nitrophenyl)indoline (1a) in high yield. The nitro group was reduced catalytically and the resulting amino function was acylated to afford the heterocycle percursor amide 3. Refluxing this amide in phosphorus oxychloride brought about a Bischler‐Napieralski type cyclodehydration to form the target 1,2‐dihydroindolo[1,7‐ab][1,5]benzodiazepine ring system. Dehydrogenation of the latter led to the fully aromatic indolo[1,7‐ab][1,5]benzodiazepine structure 5, while reduction with sodium borohydride provided the 1,2,6,7‐tetrahydroindolo[1,7‐ab]‐[1,5]benzodiazepine tetracycle 6.
Synthesis of substituted pyrrolo[2,3‐D]pyrimidine‐2,4‐diones
Authors: Etson Sandra Rae , Mattson Ronald J. , Sowell J. Walter 
Published: April 2009

AbstractA facile route for the synthesis of substituted pyrrolo[2,3‐d]pyrimidine‐2,4‐diones from substituted 2‐amino‐3‐cyano‐4‐methylpyrroles is reported.
The mass spectra of alkyl‐ and phenyl‐4‐imidazolin‐2‐ones
Authors: Holzmann G. , Krieg B. , Lautenschläger H. , Konieczny P. 
Published: April 2009

AbstractThe mass spectra of a variety of alkyl‐ and aryl‐4‐imidazolin‐2‐ones have been determined and the fragmentation mechanisms have been analyzed by deuterium labelling, high resolution and metastable transitions allowing certain differentiations of positional isomers. In contrast to the benzoid systems the mass spectra of isomeric alkyl‐4‐imidazolin‐2‐ones are distinctive. The influence of the position of substituents is demonstrated by phenyl‐4‐imidazolin‐2‐ones establishing an exact prediction of fragmentation pathways. Fragment ions (e.g. [M‐HNCO].+) which are the result of rearrangement processes were excluded for structure determinations. The ion structures involved were elucidated by collisional activation comparing model ions. Alkyl‐phenyl‐4‐imidazolin‐2‐ones give almost identical mass spectra, but the positional isomers can easily be distinguished by different fragmentation patterns in both metastable and collisional activation spectra of the molecular ions.
Thallation‐iodination studies of heterocyclic systems
Authors: Hollins Richard A. , Colnago Luiz A. , Salim Vera M. , Seidl Michael C. 
Published: April 2009

AbstractThe thallation‐iodination of 3‐carbonylindoles (4a‐f) results in orientation control with substitution occurring at the 4‐position (6a‐f). Also described is the dithallation of N‐methylpyrrole‐2‐carboxaldehyde (2).
Reduction of cyclohexanone 2‐nitrophenylhydrazone. Formation of cyclohexane‐3‐spiro‐3,4‐dihydro‐1,2,4‐benzotriazine
Authors: Sparatore Fabio , Cerri Riccardo 
Published: April 2009

AbstractThe structure of compound C12H15N3, obtained by Perkin and Riley in 1923, through the reduction of cyclohexanone 2‐nitrophenylhydrazone, was reexamined. This compound, considered originally as 3,4‐cyclotetramethylene‐4,5‐dihydro‐1,2,5‐benzotriazepine (I) and later as 2‐aminophenylazocyclohexene (II), is now defined through the nmr spectrum and chemical behaviour as cyclohexane‐3‐spiro‐3,4‐dihydro‐1,2,4‐benzotriazine (V). It is formed by spontaneous oxidation of the cyclic form of cyclohexanone 2‐aminophenylhydrazone (namely, cyclohexane‐3‐spiro‐1,2,3,4‐tetrahydro‐1,2,4‐benzotriazine) obtained through amino group addition on the hydrazone double bond.
Studies in the heterocyclic series. XV. Synthesis and reactions of the first triazaphenoxazine ring system
Authors: Okafor Charles O. 
Published: April 2009

Abstract1,4,9‐Benzo[b]triazaphenoxazine, the first and parent compound of this new heterocyclic ring, as well as its derivatives were prepared essentially by cyclo‐condensation of 2‐amino‐3‐hydroxypyridine with the appropriate 2,3‐dichloroquinoxaline in the presence of alkaline DMF or DMAC. Nitration of the product with mixed nitric and sulfuric acids gave the corresponding 13‐nitro derivative. Structural assignments were made by chemical evidence and by a study of the ultraviolet, infrared, nmr and mass spectra.
Diazapolycyclic compounds. XVI. Nmr stereochemical studies on the acid‐catalyzed oxirane ring‐opening reactions of unsubstituted, 2‐methyland 2,3‐dimethyl‐ substituted 2,3‐epoxy‐4a,12a‐diaza‐1,2,3,4,4a,5,12,12a‐octahydronaphthacene‐5,12‐diones
Authors: Gómez Contreras F. , Navarro P. 
Published: April 2009

AbstractAddition reactions in acidic media have been performed on the oxirane ring of unsubstituted, 2‐methyl‐ and 2,3‐dimethyl‐ substituted 2,3‐epoxy‐4a,12a‐diaza‐1,2,3,4,4a,5,12,12a‐octahydronaphthacene‐5,12‐diones. These reactions proceed in a stereospecific way; the Furst‐Plattner rule of 1,2‐trans‐diaxial ring‐opening is obeyed as can be deduced from the nmr stereochemical study on the terminal piperidazine‐ring moiety of the addition products. Acylation shift effects and 1,3‐syn‐diaxial interactions have been utilized to assist stereochemical assignments. The geometry of the ring corresponds in most cases to a chair slightly distorted by the sp2‐sp3 character of the nitrogens. Some of the less highly substituted among the cleavage products show certain peculiarities in their spectra, and are presumed to be in conformational equilibrium.
A convenient synthesis ofN, 5‐disubstituted‐4‐imidazoline‐2‐thiones
Authors: Doney Jeffrey J. , Altland Henry W. 
Published: April 2009

AbstractThe preparation ofN,5‐disubstituted‐4‐imidazoline‐2‐thiones from readily obtainable starting materials is described. These imidazolines are synthesized by refluxing in toluene the appropriate 2‐aminomethyl ketone hydrochloride with an equivalent of the desired isothiocyanate and an equivalent of triethylamine. The intermediate thiourea spontaneously eliminates water (removed from the reaction medium by a Dean‐Stark trap) to form the imidazoline thione.
A novel king closure and a new synthesis of 3‐deazaguanine
Authors: Srivastava Prem C. , Robins Roland K. 
Published: April 2009

AbstractThe reaction of methyl 5(4)‐cyanomethylimidazole‐4(5)‐carboxylate with hydroxylamine provided methyl 5(4)‐carboxamidoximylmethylimidazole‐4(5)‐carboxylate which cyclized on reduction Lo yield 3‐deazaguanine.
Hydrogen bonding abilities and self‐association of thiazolidin‐and imidazolidin‐2‐ones and 2‐selenones
Authors: Centric Emilie , Lauransan Jacques , Roussel Christian , Devillanova Francesco A. , Verani Gaetano 
Published: April 2009

AbstractThe hydrogen bonding abilities of iV‐methylimidazolidin‐2‐one and ‐2‐selone and thiazolidin‐2‐one and ‐2‐selenone have been studied by ir spectroscopy at 25° in carbon tetrachloride solutions, using dimethyl sulphoxide and 4‐chlorophenol as proton acceptor (KA) and proton donor (KB), respectively. The results are compared with those previously reported for N‐methylimidazolidine‐2‐thione and thiazolidine‐2‐thione. The KA values increase in each series in the order O < S < Se and Kg in the reverse order. The and KB values are discussed in terms of the substituent in ring. The self‐association constants (KD) are dependent on both KA and KB, although KA seems to be much more important.
Thermal decomposition of a sulfoximide in the presence of a carboxylic acid; an interesting rearrangement
Authors: Barnes Alan C. , Hairsine Peter W. , Kay David P. , Ramm Peter J. , Taylor John B. 
Published: April 2009

Abstract5‐Hexyl‐7‐(S‐methylsulfonimidoyl)xanthone‐2‐carboxylic acid 1a, when heated above its melting point gives a number of products including the corresponding methyl ester 1b, which arises by a novel methyl group transfer. A similar methyl transfer reaction is observed when the sulfoximide and carboxylic acid groups are present in different molecules.
A new ring closure reaction of 2‐phenoxyphenols and 3‐(phenoxy)pyridines. Synthesis of halogenated 10‐methylphenoxazines and 10‐methyl[1,4]benzoxazino[3,2‐b]pyridines
Authors: Fuhrer H. , Sutter P. , Weis C. D. 
Published: April 2009

AbstractThe cyclization of 2‐(2‐chloro(bromo)phenoxy)anilines and 3‐(phenoxy)pyridines to 10‐methylphenoxazines and 10‐methyl[1,4]benzoxazino[3,2‐b]pyridines, respectively, by means of dimethyl methylphosphonate is reported. The cyclization reaction proceeded with expulsion of methyl ether. Demethylation of some 10‐methylphenoxazines was achieved with pyridine hydrobromide. Nitration was carried out with sodium nitrite, and by reduction of the nitro groups the corresponding amines were prepared.
Facile synthesis of 2,5‐diacylthiophenes
Authors: Miyahara Yuji 
Published: April 2009

AbstractA base‐catalyzed condensation of diketo sulfides [(RCOCH2)2S] with glyoxal affording 2,5‐diacylthiophenes has been effected under mild conditions. Excellent results were readily obtained when R was various substituted phenyl, thienyl, or t‐butyl groups. Although the yield for R = methyl was poor, the increase in length of the aliphatic chain markedly increased the yields.
2‐(4′‐Fluorophenyl)imidazole. Nitration studies
Authors: Amato J. S. , Grenda V. J. , Liu T. M. H. , Grabowski E. J. J. 
Published: April 2009

AbstractReactions of 2‐(4′‐fluorophenyl)imidazole (1) and related compounds under various nitrating conditions are discussed. With 90% nitric acid in 20% oleum at −10°,1affords 2‐(4′fluorophenyl)‐4(5)‐nitroimidazole (2) in 80% yield. Reaction of2with the same reagents at 25° affords 2‐(4′‐fluoro‐3′‐nitrophenyl)‐4(5)‐nitroimidazole (4) in 90% yield, whereas with 90% nitric acid in acetic acid at 95°,2affords 4,5‐dinitro‐2‐(4′‐fluorophenyl)imidazole (5) in 80% yield. Reaction of1with 70% nitric acid in concentrated sulfuric acid at 25° affords 2‐(4′‐fluorophenyl)‐5‐hyroximinoimidazolin‐4‐one (6), which rearranges and hydrolyzes to 5‐(4′‐fluorophenyl)‐1,2,4‐oxadiazole‐3‐carboxylic acid. A discussion of these reactions is presented.
A new base‐induced ring transformation of pyrido[2,3‐d]pyrimidines
Authors: Matsumoto Jun‐Ichi , Mishio Shinsaku , Minami Shinsaku 
Published: April 2009

Abstract8‐Substituted 5,8‐dihydro‐5‐oxopyrido[2,3‐d]pyrimidine‐6‐carboxylates (3) rearranged to 8‐substituted 7,8‐dihydro‐5‐hydroxy‐7‐oxopyrido[2,3‐d]pyrimidine‐6‐carboxaldehydes (5) when treated with sodium ethoxide in an aprotic polar solvent at room temperature. The 6‐cyano analogue (18) also underwent ring transformation under the same mild conditions giving 7‐amino‐8‐ethyl‐5,8‐dihydro‐5‐oxopyrido[2,3‐d]pyrimidine‐6‐carboxaldehyde (21). However, the ring transformations of the pyrido[2,3‐d]pyrimidine bearing no N8‐substituent (12), ethyl 1‐ethyl‐1,4‐dihydro‐4‐oxo‐1,8‐naphthyridine‐ (14) and ‐quinoline‐3‐carboxylates (16) failed to occur. A mechanism is discussed.
Nitrogen bridgehead compounds. Part X (1). 1H and 13C nmr study of pyrido[1,2‐a]pyrimidines
Authors: Tóth Gábor , Hermecz István , Mészáros Zoltán 
Published: April 2009

AbstractBy 1H nmr, the predominance of the conformer with a quasi‐axial 6‐methyl group was established for the pyrido[1,2‐a]pyrimidines I‐III. The 13C nmr spectra of I‐III were completely assigned. The conjugative effect of substitution at G‐3 on 1H and 13C chemical shifts of the C‐9 methylene group parallels its effect on reactivity.
The synthesis of imidazole‐2‐thione nucleosides
Authors: Gosselin Gilles , Imbach Jean Louis , Townsend Leroy B. , Panzica Raymond P. 
Published: April 2009

AbstractRibosylation of the trimethylsilyl derivative (1b) of imidazole‐2‐thione (1a) using either stannic chloride or silver perchlorate as catalyst resulted in the formation of the acylated derivatives of 1‐(β‐D‐ribofuranosyl)imidazole‐2‐thione (3c) and 1,3‐di‐(β‐D‐ribofuranosyl)imidazole‐2‐thione (4c) with the latter predominating (4c:3c, ca. 2:1). The diribosylated nucleoside 4c was shown to be the N,N‐disubstituted product rather than the N,S‐disubstituted product by 1H nmr and 13C nmr spectroscopy. Employment of the iodine‐catalyzed fusion procedure reversed the aforementioned product ratios and provided the monoriboside 3c in excellent yield. When the trimethylsilyl derivative (5b) of 2‐methylthioimidazole (5a) was reacted with 2,3,5‐tri‐O‐benzoyl‐D‐ribofuranosyl bromide (2d) in acetonitrile, the major product was 1,3‐di‐(2,3,5‐tri‐O‐benzoyl‐β‐D‐ribofuranosyl)‐imidazole‐2‐thione (4b). The formation of 4b in this reaction is thought to arise via the Hilbert‐Johnson mechanism.
The formation of 2‐alkoxyquinolines from quinoline N‐oxides in alcoholic media
Authors: Dimsdale Michael J. 
Published: April 2009

AbstractA novel transformation of certain quinoline N‐oxides which gives rise to 2‐alkoxy substituted quinolines by the action of acetic anhydride in alcoholic media is described. In the case of t‐butyl alcohol direct formation of the carbostyril is also observed. A mechanism is advanced to explain the observed phenomena.
Abnormal displacement reaction of 2‐(chloromethyl)‐3,4‐diphenylfuran with aqueous potassium cyanide
Authors: Yamamoto Katsumi , Tanaka Akira 
Published: April 2009

Abstract2‐(Chloromethyl)‐3,4‐diphenylfuran reacted with aqueous potassium cyanide to give an α‐angelica lactone derivative (V, 3,4‐diphenyl‐5‐methyl‐2(5H)furanone), which has never been isolated in such a reaction, as the main product.
Markierungsexperimente zur fragmentierung von 1,2,3‐thiadiazolen
Authors: Timm Uwe , Meier Herbert 
Published: April 2009

AbstractThe generation of thiirenes in the thermal and photochemical nitrogen elimination of 1,2,3‐thiadiazoles is discussed in relation to oxirene formation. Isotope labelling experiments were performed with 4‐phenyl‐[4‐13C]‐1,2,3‐thiadiazole (7) as the substrate.
Das massenspektroskopische fragmentierungsverhalten von hydroxy‐ und methoxyphenazincarbonsäuren und ihren methylestern
Authors: Budzikiewicz H. , Stöckl D. , Römer A. 
Published: April 2009

AbstractDas massenspektroskopische Fragmentierungsverhalten von isomeren Hydroxy‐ und Methoxyphenazin‐1‐carbonsäuren (bzw. deren Methylester) wird in Hinblick auf eine mögliche Strukturermiltlung polysubstituierter Verbindungen diskutiert.
Amine‐induced lossen rearrangements of 3‐hydroxy‐5,6‐dihydrouracil and N‐hydroxysuccinimide benzenesulfontes
Authors: VanVerst Mary E. , Bell Charles L. , Bauer Ludwig 
Published: April 2009

AbstractThe reaction of sodium succinohydroxamate with benzenesulfonyl chloride yielded 3‐benzene‐sulfonyloxy‐5,6‐dihydrouracil, 3. Treatment of 3 with ammonia, aniline, t‐butylamine or piperidine yielded a mixture of the requisite 1,2‐bis(ureido)ethane and 1‐curboxamido‐2‐imidazolidone. Acylation of N‐hydroxysuccinimide with benzenesulfonyl chloride furnished N‐benzenesulfonyl‐oxysuccinimide, 10. Aniline or t‐butylamine were used as representative amines to demonstrate their capability of inducing a Lossen degradation on 10 to afford the corresponding β‐ureido ‐propionamide.
Preparation of novel heterocyclic systems from isatoic anhydrides
Authors: Sunder Shyam , Peet Norton P. 
Published: April 2009

AbstractIsatoic anhydride (1a) and 5‐chloroisatoic anhydride (1b) were treated with 2‐(1‐methylhydrazino)ethanol (2) to produce 2‐aminobenzoic acid 2‐(2‐hydroxyethyl)‐2‐methylhydrazide (3a) and its 5‐chloro analog 3b, respectively. Treatment of 3a and 3b with carbon disulfide gave, respectively, 2,3‐dihydro‐3‐[(2‐hydroxyethyl)methylamino]‐2‐thioxo‐4‐(1H)quinazolinone (4a) and its 6‐chloro analog 4b. Compounds 4a and 4b afforded 5,6‐dihydro‐5‐methyl‐2‐thioxo‐4H,8H‐[1,3,5,6]oxathiadiazocino[4,5‐b]quinazolin‐8‐one (5a) and its 10‐chloro analog 5b, respectively, upon treatment with thiophosgene. Compound 5a could be produced directly from 3a and thiophosgene. Treatment of 4a and 4b with trifluoroacetic anhydride followed by potassium carbonate gave 3,4‐dihydro‐4‐methyl‐2H,6H‐[1,3,4]thiadiazino[2,3‐b]quinazolin‐6‐one (7a) and its 8‐chloro analog 7b, respectively. Treatment of 4a with thionyl chloride also gave 7a, but 4b and thionyl chloride afforded a mixture of 7b and 8‐chloro‐3,4‐dihydro‐4‐methyl‐2H,6H‐[1,3,4]oxadiazino[2,3‐b]quinazolin‐6‐one (10). The dimethyl analogs of 4a and 4b (13a and 13b) upon treatment with thiophosgene afforded 3,4‐dihydro‐2,2,4‐trimethyl‐2H,6H‐[1,3,4]oxadiazino[2,3‐b]quinazolin‐6‐one (14a) and its 8‐chloro analog 14b, respectively.
Novel heterocycles. 4. Synthesis of the pyrido[2,3‐c]‐1,2‐thiazine ring system
Authors: Coppola Gary M. , Hardtmann Goetz E. 
Published: April 2009

AbstractThe reaction of 2‐chloronicotinonitrile with N‐methylmethanesulfonamide and subsequent treatment with base furnished the novel pyrido[2,3‐c]‐1,2‐thiazine ring system 7. Spectrally, it was determined that the predominant tautomer in solution was the 4‐amino form 7a. Acidic hydrolysis of 7 furnished the 4‐oxo tautomer 8b, compound 8b was alkylated on oxygen with 1‐bromopentane in the presence of sodium hydride. Reaction of 8b with isocyanates occurs at the 3 position to produce carboxanilides 10. Spectral characteristics of these compounds are also discussed.
A new synthesis of 10‐arylisoalloxazines (10‐arylflavins)
Authors: Yoneda Fumio , Shinozuka Kazuo , Tsukuda Kinshiro , Koshiro Akira 
Published: April 2009

AbstractThe condensation of 6‐arylamino‐ and 6‐alkylaminouracils with nitrosobenzenes in a mixture of acetic anhydride and acetic acid gave the corresponding 10‐aryl‐ and 10‐alkylisoalloxazines (flavins).
Mass spectral fragmentation pattern of 2,2′‐bipyridyls. Part XII. 2,2′‐Selenodipyridine
Authors: Keats N. G. , Summers L. A. 
Published: April 2009

AbstractThe mass spectrum of 2,2′‐selenodipyridine obtained by electron impact is reported. The base peak in the spectrum is due to the C5H4N+ ion formed principally by rupture of the central bonds. The molecular ion gives rise to a peak of 50% of the intensity of the base peak. Other fragmentations include loss of H, Se and CSe from the molecular ion and HCN from the M‐1 ion.