bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthèse et étude conformationnelle de dioxa‐1,3 aza‐9 spiro[5,5]undecanes
Authors: Bassus J. , Anker D. , Pacheco H. , Duplan J. C. 
Published: April 2009

AbstractLa synthèse de nouveaux cycles dioxa‐1,3 aza‐9 spiro[5,5]undécane a été réalisée suivant le schèma représenté dans la figure 2. Les butyrophénones 6 obtenues, ont une activité neuro‐leptique voisine de celle de l'halopéridol. Leur étude pharmacologique fait l'objet d'une publication à part (2). L'étude conformationnelle des dioxa‐1,3 aza‐9 spiro[5,5]undécanes permed de mettre en évidence quatre conformations A, B, C et D, comme le montre la figure 4. L'existence de ces conformations dépend de la nature des substituants R et R' du cycle dioxanne. Ainsi, pour les composés où R ≠ H et R' = H, les quatre conformations sont possibles avec prédominance des formes A et B. Si R et R' sont différents de H, seule la conformation A existe à plus de 99%. Enfin, dans le cas où R = R' = H, les quatre conformations sont possibles avec égalité de population pour les conformères A et B d'une part et C et D d'autre part, A et B étant majoritaires. La présence de la chaîne fluorophénylbutyrique sur l'azote pipéridinique, ne semble pas apporter de modifications stéréochimiques dans la partie hétérocy clique.
The reactions of ethyl 3,4‐dihydro‐4‐quinazolylacetate and its derivatives with cyclopentanone. An attempt at the synthesis of the 6,8‐diazasteroid system VII
Authors: Yamazaki Takao , Matoba Katsuhide , Shirokawa Atsuko , Castle Raymond N. 
Published: April 2009

AbstractThe reaction of ethyl 3,4‐dihydro‐4‐quinazolylacetate (1a) with cyclopentanone in the presence of trifluoroacetic acid gave mainly two decomposition products, carbostyril (VIII) and ethyl 2‐aminocinnamate (IX). Two compounds which are suggested to have the 6,8‐diazasteroid skeleton were also obtained in poor yield. Ethyl 3,4‐dihydro‐2‐p‐methoxyphenyl‐4‐quinazolylacetate (1b), however, gave 2‐p‐methoxyphenylquinazoline (XII) as a decomposition product and did not condense with cyclopentanone. Furthermore, two ethyl 3,4‐dihydroquinazolylacetates substituted at the 2‐position with cyclohexyl (1c) and methyl (1d) groups could not be converted to the expected diazasteroid system.
Substituted 5‐aryl‐ or 5‐diphenylmethyl‐3‐alkyl‐2‐oxazolidones as anticonvulsants
Authors: Jaiswal R. K. , Parmar S. S. 
Published: April 2009

AbstractSeveral 5‐aryl‐ or 5‐diphenylmethylhydracrylyl hydrazides were synthesized and converted into 5‐aryl‐ or diphenylmethyl‐2‐oxazolidones. The latter compounds were further alkylated into their corresponding 5‐aryl‐ or 5‐diphenylmethyl‐3‐alkyl‐2‐oxazolidones as possible anticon‐vusants.
Photoinduced fragmentation and rearrangement of phenyl substituted epoxyethylphosphonates
Authors: Griffin Claibourne E. , Kraas Ekkehard , Terasawa Hirofumi , Griffin Gary W. , Lankin David C. 
Published: April 2009

AbstractAn alternative source to phosphonocarbenes is described using phosphorus substituted oxiranes as precursors which compliments the conventional diazo route to these transient species. The results are in accord with previous theories advanced to rationalize the mode of photocyclo‐elimination of a variety of other unsymmetrically substituted oxiranes.
Regiospecific photohydroxyalkylation of pentafluoropyridine
Authors: Sket Boris , Zupan Marko 
Published: April 2009

AbstractIrradiation of 1‐hydroxyalkane solutions of pentafluoropyridine in the presence of benzo‐phenone resulted in regiospecific substitution at position 4, thus forming 2,3,5,6‐tetrafluoro‐4‐(1‐hydroxyalkyl)pyridine.
The synthesis and reactions of certain 3‐substituted‐2,1‐benzisothiazoles
Authors: Albert Anthony H. , O'Brien Darrrell E. , Robins Roland K. 
Published: April 2009

AbstractA new and general synthesis of 2,l‐benzisothiazolin‐3‐ones (2) is described from the corresponding isatoic anhydride (3) and potassium hydrogen sulfide which gives the thioanthranilic acid (4) which is readily oxadized and ring closed to 2 with hydrogen peroxide. Phosphorus oxy‐chloride converted 3‐hydroxy‐2,1‐benzisothiazole to 3‐chloro‐2,1‐benzisothiazole which gave a number of different 3‐substiluted 2,1‐benzisothiazolesby nucleophilic substitution of the 3‐chloro group. Rleetrophilie substitution of 1‐methyl‐2,1 ‐benzisothiazoIin‐3‐one (2i) proceeded readily to give the corresponding 5‐bromo‐, 5‐nitro‐, and 5‐chlorosulfonyl‐1‐methyl‐2,1‐benzisothiazolin‐3‐one. This appears to be a good synthetic route to such 2,1‐benzisothiazole derivatives.
Carbon‐13 nuclear magnetic resonance spectra of isoquinoline alkaloids
Authors: Singh S. P. , Parmar S. S. , Stenberg V. I. , Farnurn S. A. 
Published: April 2009

AbstractThe 13C nmr ehemieal shifts of 1,2,3,4‐tetrahydroisoquinoline, salsolidine and laudanosine are reported. The various carbon resonances have been assigned on the basis of chemical shift theory, intensity of the signals, multiplicities generated in SFORD spectra and the comparison with model compounds.
Quinazolincs and 1,4‐benzodiazepines. LXXXVI. The synthesis of imidazothienodiazepines and imidazopyrazolodiazepines
Authors: Fryer R. Ian , Earley James V. , Walser Armin 
Published: April 2009

AbstractThe thieno[3,2‐e][1,4]diazepin‐2‐one (1a), the thieno[2,3‐e] [ 1,4] diazepin‐2‐one (1b), the pyrazolo[3,4‐e][1,4]diazepin‐2‐one (1c) and a chloro analog of 1b, compound 1d, were each converted to derivatives of the novel tricyclic ring systems 4H‐imidazo[1,5‐a]thieno[2,3‐f] [1,4]‐diazepine, 4Himidazo[1,5a]thieno[2,3f][1,4]diazepine and 4H‐imidazo[ 1,5‐a]pyrazolo[4,3‐f]‐[1,4]diazepine. Depending on the substituents desired on the imidazo ring, two different synthetic pathways were employed.
The stereochemistry of 2‐oxoindolin‐3‐ylidene derivatives
Authors: Long D. R. , Richards C. G. , Ross M. S. F. 
Published: April 2009

AbstractThe stereochemistry of a number of functionally‐substituted 2‐oxoindolin‐3‐ylidene derivatives has been established by a study of pmr and ir spectroscopy. These compounds have been shown to exist as one isomer with the exception of the substituted acetonitriles.
Sur la ribosylation de divers mercapto‐2 benzoazoles
Authors: Cosselin G. , Loukil H. F. , Mathieu A. , Mesli A. , Imbach J‐L. 
Published: April 2009

AbstractNous avons effectué en série mercapto‐2 benzoazole une étude comparative de la réaction de ribosylation de ces bases en utilisant trois techniques parmi les plus employées: la fusion acido‐catalysée, la condensation des dérivés silylés des aglycones avec un acétoxy‐1 et avec un halogéno‐1 sucre.Les N‐β‐nucléosides correspondants ont, dans tous les cas, été isolés et identifiés sans ambiguité. On peut noter toutefois la réactivité particuliére observée en série benzimidazole puisque nous avons pu mettre en évidence dans certaines de ces condensations la formation du N,N ‐diriboside et d'un anhydro‐2,2′ nucléoside.
Synthesis of 4‐imidazolin‐2‐ones via the birch reduction of hydantoins
Authors: Divanfard Hosein R. , Ibrahim Yehia A. , Joullié Madeleine M. 
Published: April 2009

AbstractThe reduction of 5‐(5‐methyl‐2‐furyl)hydantoin to 4‐(5‐methyl‐2‐luryl)‐4‐imidazolin‐2‐one is described.
8‐Methyl‐5,6,7,8‐tetrahydroeoumarin
Authors: Feutrill G. I. , Mirrington R. N. 
Published: April 2009

AbstractAcid‐catalysed cyclodehydration of β‐(2‐keto‐3‐methylcyclohex‐3‐enyl)propionic acid proceeded efficiently to 8‐methyl‐5,6,7,8‐tetrahydrocoumarin.
A general method for the preparation of N‐monosubstituted‐3‐isothiazolamines
Authors: Rokach J. , Hamel P. 
Published: April 2009

AbstractWe describe here a novel and general high yield method for the synthesis of 3‐alkyl and arylaminoisothiazoles, a previously unknown group of isothiazoles, by the reaction of ammonia with 3‐halo‐2‐alkylisothiazolium salts. The mechanism of the reaction probably involves a ring opening followed by a recyclization to the title compounds.
Die bildung von thiirenen
Authors: Timm Uwe , BÜhl Hanspeter , Meier Herbert 
Published: April 2009

AbstractPhotochemical nitrogen elimination of 1,2,3‐thiadiazoles leads to primary fragments (1, X = S), which are able to cyclize to thiirenes (2, X = S). An exception is found for bicyclic systems like 4. These results, gained by isotope labelling experiments are related to the oxirene formation of α‐oxocarbenes.
Constituents of cannabis sativa L. An improved method for the synthesis of dl‐cannabichromene
Authors: Eisohly Mahmoud A. , Boeren Edward G. , Turner Carlton E. 
Published: April 2009

AbstractA new procedure was developed for the synthesis of cannabichromene (III) which involves reflux of equimolar amounts of olivetol (I), citral (II) and t‐butylamine in toluene for 9 hours. The purification of III was best achieved by sodium borohydride reduction of unreacted II followed by column chromatography on 1% sodium hydroxide impregnated silica gel 60‐PF. The yield of III (62.0%) was much higher than that reported in the literature.
Novel chlorination of 4′,5,7‐trihydroxyflavanone with cupric chloride‐oxygen
Authors: Takizawa Yasuomi , Mitsuhashi Tatsuo 
Published: April 2009

AbstractNovel chlorination of 4,5,7‐trihydroxyflavanone with copper(II) chloride and oxygen is described. 6,8‐Dichloro‐4′,5,7‐trihydroxyflavanone (2) and 6,8‐dichloro‐4,4′,5,7‐tetraacetoxyflav‐3‐ene (3) were newly synthesized.
A synthesis of pyrrolo[ 3,2,1‐kl] phenothiazine and derivatives
Authors: Hollins Richard A. , Pinto Angelo C. 
Published: April 2009

AbstractA synthesis of pyrrolo[3,2,1‐kl]phenothiazine (1) is described. Electrophilic substitution of 1 leads to functionalization at the 2 position.
Nouvolle synthcse de la dihydro‐5,6 methoxy‐6 2H‐pyrannone‐5
Authors: Saroli Alfred , Descours Denis , Anker Daniel , Pacheco Henri 
Published: April 2009

AbstractL'obtention de la cétone α,β éthylénique 5 à partir de la cétone saturée 1 est réalisée en quatre etapes avec un rendement de 35%. L'intermédiaire de réaction est Pacetal brome obtenu sous forme d'un mélange des deux isomères 6 et 7; leur stéréochimie et leur conformation sont mises en évidence par étude rmn à 250 MHz. Lors de leur débromhydratation, une isomérisation de I'acetal α,β éthylénique 4, relativement aisée, peut ětre réalisee par migration de la double liaison pour conduire à 1′acétal β,γ éthylénique 10.
Meso heterocyclic analogues of 9,10‐dihydroanthraeene. XIII. On the structure of the products of diacetylalion of phenoxathiin: A correction
Authors: Coïc J.‐P. , Saint‐Ruf G. 
Published: April 2009

AbstractThe diacetylation of phenoxathiin under the typical conditions for Friedel‐Crafts reaction results in a mixture consisting of 2,7‐diacetylphcnoxathiin (3) and 2,8‐diacetylphenoxathiin (9). The compound hitherto descrihed in the literature as 9 proved to be in reality the mixture. For the first time, the compound 3 was isolated, purified and had its structure established. 3,4′‐Diethyldiphenyloxide as well as 2,7‐ and 2,8‐diethylphenoxathiins and their sulphones and sul‐phoxides have been synthesized.
New syntheses of pyrimido[4,5‐c]pyridazines related to fervenulin
Authors: Senga Keitaro , Sato Junko , Kanamori Yukako , Ichiba Misuzu , Nishigaki Sadao , Noguchi Mitsukò , Yoneda Fumio 
Published: April 2009

AbstractPyrimido[4,5‐c]pyridazines related to an antibiotic fervenulin were prepared by two routes: one involving the reaction of 6‐hydrazino‐1,3‐dimethyl(or 3‐methyl)uracil with phenacyl bromides, and the other involving the reaction of 6‐benzylidenehydrazino‐1,3‐dimethyluracils with dimethyl‐formamide dimethylacetal.
Studies on 1H‐ and 2H‐N‐alkylpyrazolo[3,4‐d]pyridazin‐4(5H)ones
Authors: Gelin Suzanne , Hartmann Daniel 
Published: April 2009

AbstractA series of two N‐substituted‐3(5)acyl4‐ethoxycarbonyl‐5(3)substituted isomeric pyrazoles underwent ring closure with hydrazine and methylhydrazine to give the new anticipated N(1)‐or N(2)alkyl‐3,7‐disubstituted pyrazolopyridazin‐4(5H)ones. The purpose of this study was to determine distinguishing criteria between the two isomers. From the comparative 1 H‐ and 1 3C‐nmr spectra, sufficiently significant differences were observed. Uv and ir spectra showed no significant differences.
1H Nmr study of the preferred conformations in N‐alkylgranatanine‐3‐spiro‐5′‐hydantoins
Authors: Trigo G. G. , Avendaño C. , Ballesteros P. , Gonzalez A. 
Published: April 2009

AbstractThe conformations of a new series of compounds of the general structure N‐alkylgranatanine‐3‐spiro‐5′‐hydantoin, synthesized in our laboratory from the corresponding 9‐alkyl‐9‐azabieyclo‐[3.3.1 ]nonan‐3‐ones, were studied by 1 H nmr spectroscopy at different pH values in some instances. We have assigned boat conformations for the spiropiperidines.
Syntheses of 5‐amino‐3‐(β‐d‐ribofuranosyl)imidazo [4,5‐b] pyridin‐7‐one (1‐deazaguanosine) and related nucleosides
Authors: Cline Barry L. , Panzica Raymond P. , Townsend Leroy B. 
Published: April 2009

AbstractThe synthesis of 5‐amino‐3‐(β‐D‐ribofuranosyl)imidazo[4,5‐b ]pyridin‐7‐one (1‐deazaguano‐sine) has been accomplished by three different methods. The 6‐thioguanosine analog 5‐amino‐3‐(β‐D‐ribofuranosyl)imidazo [4,5‐b ]pyridin‐7‐thione (1‐deaza‐6‐thioguanosine) has been prepared in situ by a reduction of the corresponding disulfide. The synthesis of various nucleoside precursors of the above compounds by several condensation procedures are described. The procedures used to unequivocally determine the site of ribosylation and anomeric configuration are also discussed.
Etude de la réaction de l'acé'tylacé'tate d'éthyle avec les diamino‐1,5 imidazoles
Authors: Bernardini A. , Viallefont Ph. , Zniber R. 
Published: April 2009

AbstractL'action d'un β‐cetoéster tel Fàcétylacétate d'éthyle sur les diamino‐1,5 imidazoles conduit a deux types de réactions concurrentes et permet de synthétiser des imidazo[1,5‐b]triazépinones et des imidazo[4,5‐b]pyridinones. Les produits obtenus ont une structure lactamique qui correspond à l'action de la fonction ester sur le groupe amino non hydrazinique du diamino‐imidazole. Un nouveau type de transposition des imidazotriazépinones en imidazopyridinones a été mis en évidence, il résulte de la réactivité particulière de la double liaison C=N du cycle à sept éléments.
Heterocyclic compounds. X. A new synthesis of thiadiazasteroids
Authors: Manhas M. S. , Sugiura M. , Chawla H. P. S. 
Published: April 2009

AbstractThe reaction of ν‐ketoacids or ν‐aldehydo acids with o‐amino amides results in the formation of 4‐quinazolones. Using this reaction a number of polyheterosteroid analogs were synthesized. Thus, when 2‐amino‐3‐carboxamido‐4,5,6,7‐tetrahydrobenzothiophene (9) was refluxed with levulinic acid (10) in a high boiling solvent, thiadiazasteroid analog (11) was obtained in 78% yield. It was found that this facile one‐step reaction could be used to synthesize a variety of tetra and pentacyclic compounds. Nmr spectroscopy was used to assign stereochemistry to the 17‐methyl “steroids” (31) and (32).
[1]Benzofuro[2,3‐d]pyridazine III. Etude de la dichloro‐1,4 benzofuropyridazine
Authors: de Sevricourt Michel Cugnon , Robba Max 
Published: April 2009

AbstractLes réactions de substitution régiosélectives de la dichloro‐1,4 benzofuropyridazine concernent la position 1. La chloro‐4 hydrazino‐1 benzofuropyridazine se prěte a des cyclisations menant à des chloro‐6 s‐triazolo[1,2‐b]benzofuropyridazines et à la chloro‐6 tétrazolo[1,5‐b]benzo‐furopyridazine dont les substitutions nucléophiles sont étudiées.
Benzomorphan related compounds. VII. Synthesis of benzothienomorphans
Authors: Alvarez M. , Bosch J. , Feliz M. 
Published: April 2009

AbstractThe synthesis of some benzo [b] thieno [2,3‐f] ‐ and [3,2‐f] morphans by the Grewe method is described. Spectroscopic data of these compounds and of the intermediate isomeric tetrahydropyridines are included. A side‐product isolated from the aluminum bromide cyclization of the 2‐(2‐benzothienylmethyl)tetrahydropyridine IVd is reported and a mechanism for its formation is proposed.
Synthesis of pyridyloxadiazoles 2. 2‐(Oxadiazolyl)pyridines and 2,6‐bis(oxadiazolyl)pyridines as analogues of pyridinolcarbamate
Authors: Suárez Cecilia , Diparsia Maria T. , Márquez Victor E. 
Published: April 2009

AbstractFour 2‐(oxadiazolyl)pyridines and three 2,6‐bis(oxadiazolyl)pyridines, considered as potential analogues of pyridinolcarbamate (PC), were prepared and screened for antithrombotic activity against ADP‐ and collagen‐induced platelet aggregation. All the compounds showed activity below the critical response expected for this category of drugs.
A new synthesis of 3,6‐dialkyl, diaryl and diheterocyclic‐1,2‐dihydro‐l, 2,4,5‐tetrazines
Authors: Cohen Victor Israel 
Published: April 2009

AbstractSome 3,6‐dialkyl, diaryl and diheterocyclic‐1,2‐dihydro‐1,2,4,5‐tetrazines have been synthesized from the action of hydrazine on aliphatic selenonesters, and aromatic and heterocyclic selenoamides.
Preparation of isatoates from isatoic anhydride
Authors: Heyman Duane A. 
Published: April 2009

AbstractA wide variety of alkyl isatoates can be prepared in good yield from the high temperature reaction of isatoic anhydride with alcohols. Isatoates were found to undergo an apparent high temperature rearrangement reaction. Proposed reaction schemes are presented for the formation of isatoates and the subsequent rearrangement reaction.
3‐Diazopyrazolo[3,4‐b] pyridine, a versatile synthon for new heterocyclic systems
Authors: Kočevar M. , Stanovnik B. , Tišler M. 
Published: April 2009

Abstract3‐Diazopyrazolo[3,4‐b] pyridine was synthesized and its transformations were investigated. With reactive methylene compounds the corresponding hydrazones are formed and they can be cyclized into condensed 1,2,4‐triazine derivatives. With amines of thiols the diazo compound forms triazenes or diazosulfides. From hydrazines tetrazenes are formed first and they give upon fragmentation a mixture of N‐N or C‐N bond fission products. The diazo compound undergoes cycloaddition, reacting as a 1,2‐dipole. 3‐Azidopyrazolo [3,4‐b] pyridine was prepared and converted into the tetrazolo isomer, whereas the 3‐amino compound was used for the synthesis of some pyridopyrazolopyrimidines.
Synthesis of 3(2‐ and 4‐Pyridinyl)‐1,3,4‐oxadiazol‐2(3H)ones
Authors: Giacobbe Thomas J. 
Published: April 2009

AbstractThe synthetic objective of preparing halo‐ and halo‐ plus alkoxy‐substituted pyridyloxadiazolones was achieved by allowing an alkali metal salt of an oxadiazolone to displace a leaving group on a halo‐ or halo‐ plus alkoxy‐substituted pyridine, respectively. Other routes failed to give the desired compounds, and they are briefly discussed.
Synthesis of the macrocyclic polythia ether, [7.7](2,6)dithia(2,5)thiophenophane
Authors: Bhattacharjya Anup , Hortmann Alfred G. 
Published: April 2009

AbstractThe macrocyclic polythia ether [7.7](2,6)dithia(2,5)thiophenophane 2 has been prepared by condensation of the dilithio salt of propane‐1,3‐dithiol with 2,5‐bis (chloromethyl)lhiophene.
Fluoroazoles. II. Synthesis and 1H and 19F Nmr spectra of 2‐, 4‐, and 5‐Fluoro‐1‐methylimidazole
Authors: Fabra F. , Gálvez C. , González A. , Viladoms P. , Vilarrasa J. 
Published: April 2009

AbstractThe three possible ring‐monofluorinated N‐methylimidazoles have been prepared by photochemical irradiation of the corresponding diazonium tetrafluoroborates. 5‐Fluoro‐1‐methyl‐imidazole was also obtained by methylation of 1‐acetyl‐4‐fluoroimidazole. The 1H and 19F nmr spectra of these N‐methylated fluoroazoles are compared, and the predominance of one tautomeric form in 4(5)‐fluoroimidazole is discussed.
Syntheses with α‐heterosubstituted phosphonate carbanions. VIII. An unexpected entry into quinolines
Authors: Zimmer Hans , Nene Dilip M. 
Published: April 2009

AbstractThe carbanions derived of certain diphenyl‐1‐(4‐nitroanilino)‐1‐(substituted‐aryl)methanephosphonates reacted with phenylpropargyl aldehyde, giving not the expected yne‐enamines, but rather 2‐phenyl‐4‐benzyIquinolines.
Oxidation of quinazoline and quinoxaline by xanthine oxidase and aldehyde oxidase
Authors: Mccormack John J. , Allen Barbara A. , Hodnett C. Nicholas 
Published: April 2009

AbstractQuinazoline is oxidized by xanthine oxidase initially (and rapidly) to 4‐hydroxyquinazoline which subsequently is oxidized more slowly to 2,4‐dihydroxyquinazoline. Both oxidative reactions are inhibited strongly by allopurinol. Quinazoline is oxidized by aldehyde oxidase to 4‐hydroxyquinazoline but within a short time (3–5 minutes) the reaction ceases; the proposal that cessation of reaction is due to product inhibition is rendered untenable by our observation that 4‐hydroxyquinazoline is rapidly oxidized by aldehyde oxidase to 2,4‐dihydroxyquinazoline. Preincubation of aldehyde oxidase with quinazoline results in complete inhibition of the ability of the enzyme to oxidize 4‐hydroxyquinazoline and the standard substrateN‐methylnicotinamide. It appears therefore that quinazoline is able to react with aldehyde oxidase and inactivate it. Quinoxaline and 2‐hydroxyquinoxaline are not oxidized by xanthine oxidase but are converted by aldehyde oxidase to 2,3‐dihydroxyquinoxaline; all oxidations mediated by aldehyde oxidase are inhibited completely by menadione.
Synthesis and structure of dihydro‐1,2,4‐triazin‐6(1H) ones
Authors: Camparini Alfredo , Celli Angela Maria , Ponticelli Fabio , Tedeschi Piero 
Published: April 2009

AbstractReactions of the iminoesters 3a‐c with hydrazine or 1,2‐dimethylhydrazine gave 4,5‐dihydro‐4a‐c or 2,5‐dihydro‐1,2,4‐triazin‐6(1H) ones 7a‐c, respectively. When methylhydrazine was employed, 1‐methyl‐4, 5‐dihydro‐ 5a‐c and 2‐methyl‐2,5‐dihydro‐1,2,4‐triazin‐6(1H) ones 6a‐c were obtained. Compounds 6a‐c exist as zwitterions in the solid state and in polar aprotic solvents.
Tetracyclic phenothiazines. III. . Intermolecular hydride transfer in acid induced disproportionation of 1,2‐dihydro‐3‐hydroxy‐3H‐pyrido[3,2,1‐kl] phenothiazines
Authors: Martin A. R. , Kim S. H. , Peng G. W. , Siegel G. V. , Yale T. J. 
Published: April 2009

Abstract1,2‐Dihydro‐3‐hydroxy‐3H‐pyrido[3,2,1‐kl]phenothiazines and 1H‐pyrido[3,2,1‐kl]phenothiazines undergo acid catalyzed disproportionation with intermolecular hydride transfer to form pyrido[3,2,1‐kl]phenothiazinium salts and 1,2‐dihydro‐3H‐pyrido[3,2,1‐kl]phenothiazines. Sodium borohydride reduction of 3‐alkyl‐ or 3‐arylpyrido[3,2,1‐kl]phenothiazinium salts gives 3‐alkyl‐ or 3‐aryl‐1H‐pyrido[3,2,1‐kl]phenothiazines. In the presence of a proton source, borohydride reduction of pyrido[3,2,1‐kl]phenothiazinium fluoroborate or 3‐chloropyrido‐[3,2,1‐kl]phenothiazinium perchlorate gives 1,2‐dihydro‐3H‐pyrido[3,2,1‐kl]phenothiazine, while 1H‐pyrido[3,2,1‐kl]phenothiazine is formed in aprotic solvents with pyridine present.
Studies on the synthesis of heterocyclic compounds. Part II. Action of phosphorus oxychloride on N‐Methyl‐N‐1‐phenyl‐3‐methylpyrazol‐5‐yl)‐2‐acetamidobenzamide
Authors: Plescia S. , Daidone G. , Sprio V. , Aiello E. , Dattolo G. , Cirrincione G. 
Published: April 2009

AbstractDuring attempts to prepare the tricyclic ring system of type III by cyclization of N‐methyl‐N‐(1‐phenyl‐3‐methylpyrazol‐5‐yl)‐2‐acetamido benzamide (Ib) under Bischler‐Napieralski reaction conditions, the formation of the macro‐heterocycle IV was observed, whose structure was determined on the basis of analytical and spectroscopic data as well as on some transformation products.
Synthesis of 4‐hydroxy‐ and 4‐mercaptoquinazoline derivatives
Authors: Cohen Victor Israel 
Published: April 2009

AbstractThe reaction of selenoesters with o‐aminobenzamide and o‐aminothiobenzamide derivatives led to the formation of 4‐hydroxy‐ and 4‐mercaptoquinazolines. Their structures were elucidated by means of elemental analyses and spectropic data (nmr and ms).
Tetracyclic phenothiazines IV . Synthesis of 1,2,3,4‐Tetrahydro‐azepino [3,2,1‐kl] phenothiazin ‐4‐one
Authors: Kim Sun H. , Martin Arnold R. 
Published: April 2009

AbstractThe synthesis of 1,2,3,4‐tetrahydroazepine[3,2,1‐kl]phenothiazin‐4‐one was accomplished by cyclization of phenothiazine‐10‐butanoic acid using phosphorus pentoxide and absolute ethanol. The title compound represents the first reported example of the azepino[3,2,1‐kl]phenothiazine ring system. A vastly improved malonic ester‐type synthesis of the precursor acid has also been developed.