bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of 1‐substituted‐7‐hydroxyquinolinium salts
Authors: Ranganathan N. , Storey B. T.
Published: May 2009

The reaction of 7‐acetoxyquinoline with trifluorosulfonate esters of primary alcohols in methylene chloride or acetonitrile, followed by acid hydrolysis, provides a general synthesis of 1‐substituted‐7‐hydroxyquinolines, whose phenolate anions are fluorescent.
4‐Amino‐3‐mercapto‐4H‐1,2,4‐triazoles and propargyl aldehydes: A new route to 3‐R‐8‐aryl‐1,2,4‐triazolo[3,4‐b]‐1,3,4‐thiadiazepines
Authors: Heindel Ned D. , Reid Jack R.
Published: May 2009

The pendant amino and mercapto groups on 4‐amino‐3‐mercapto‐4H‐4H‐1,2,4‐triazoles can be cyclized by phenylpropargyl aldehydes. The aldehydes experience Michael addition of the SH to the alkyne linkage and imine formation between the NH2 and the aldehyde carbonyl to produce 3‐R‐8‐aryl‐1,2,4‐triazolo[3,4‐b]‐1,3,4‐thiadiazepines.
A Carbon‐13 and nitrogen‐15 NMR study of some nitrogen heterocycles
Authors: Buchman Russell , Komoroski Richard A.
Published: May 2009

A number of phenyl‐substituted nitrogen heterocycles and the corresponding 2,6‐diethylphenyl derivatives were examined by 13C nmr in order to verify that the heterocyclic ring system was the same in both series. The heterocyclic ring carbon shifts did not differ substantially between the phenyl and 2,6‐diethylphenyl derivatives for all systems except one, where substantial differences were also seen in the 15N chemical shifts. Acetylated derivatives were prepared to confirm the cyclization mode in this latter case.
Synthesis of pyridines from dicyanopyrimidines. A diels‐alder approach to the c‐ring of streptonigrin
Authors: Martin John C.
Published: May 2009

The reaction of dicyanopyrimidines with yneamines gave pyridines which could potentially serve as precursors to analogs of streptonigrin.
4‐(Arylaminothiocarbonyl)‐1‐(1‐o‐methoxyphenylcarbamido)‐ethylpiperazines as anticonvulsants
Authors: Pandey Bhagwan R. , Kumar Sushil , Singh Shiva P. , Parmar Surendra S.
Published: May 2009

Several 4‐(arylaminothiocarbonyl)‐1‐(1‐o‐methoxyphenylcarbamido)‐ethylpiperazines were synthesized and evaluated for their anticonvulsant activity against pentylenetetrazol‐induced seizures in mice. The ability of substituted piperazines to inhibit in vitro respiratory activity of rat brain homogenates was also determined to study their structure‐activity relationship.
Chemistry of the phenoxathiins and isosterically related heterocycles. X. Correlation of the dihedral angles of phenoxathiin analogs with the 13NMR chemical shifts of the sulfur bearing la carbon
Authors: Caldwell Steven R. , Turley James C. , Martin Gary E.
Published: May 2009

The observation of a linear relationship between the 13C‐nmr chemical shifts of the C‐la carbon and the dihedral angle in a series of phenoxathiin analogs is reported. Presently available data, although limited, is presumed to be indicative of a more general behavior which has not been previously recognized or utilized. Extension of this observation to include other sulfur containing tricyclic systems may be expected to provide a useful means for the preliminary estimation of dihedral angles from solution 13C‐nmr measurements after suitable parameterization.
Benzomorphan related compounds. XIV. Synthesis of 2‐(2‐pyrrolylmethyl)‐ and 2‐(2‐indolylmethyl)tetrahydropyridines and cyclization to pyrrolo[3,2‐f]morphans
Authors: Bosch Joan , Mauleón David , Boncompte Fontsanta , Granados Ricardo
Published: May 2009

The synthesis of 2‐{2‐pyrrolylmethyl)‐ and 2‐(2‐indolylmethyl)tetrahydropyridines by condensation of 2‐cyanopyridines with appropriate pyrrole or indole derivatives followed by ketone reduction, quaternization and sodium borohydride reduction are described. The acid‐induced cyclization of 2‐(2‐pyrrolylmethyl)tetrahydropyridines affords 4,5,6,7,8,9‐hexahydro‐4,8‐methanopyrrolo[2,3‐d]azocine systems (pyrrolo[3,2‐f]‐morphans), although the method fails with N‐benzyl substituted pyrroles. The acid treatment of 2‐(2‐indolylmethyl)tetrahydropyridines and of 2‐indolyl tetrahydro‐2‐pyridyl ketones is not a suitable procedure for the preparation of indolo[3,2‐f]morphans, because of the protonation of indole nucleus or carbonyl group, respectively.
Carbon‐13 Nmr spectroscopy of methoxy‐ and acetoxyaurones
Authors: Sharma Anil , Chibber S. S.
Published: May 2009

The 13C nmr chemical shifts of methoxy and acetoxyaurones are reported. The signals are assigned on the basis of substituent effects and comparison with structurally related compounds. Assignments are also verified by Sford.
S‐demethylation of nitrogen heterocycles
Authors: Chen Shih‐Fong , Panzica Raymond P.
Published: May 2009

When 3‐chloro‐4,5‐diaminopyridazine (2) was treated with sodium methylmercaptide in refluxing N,N‐dimethylformamide, two heterocycles were formed and isolated, neither of which was the expected 3‐methylthio‐4,5‐diaminopyridazine (3). A thorough spectral analysis of these heterocycles showed them to be 4‐methylthioimidazo[4,5‐d]pyridazine (5) and imidazo[4,5‐d]pyridazine‐4‐thione (6). N,N‐Dimethylformamide was found to provide the one carbon unit required for the formation of 5. The origin of 6 was shown to be a result of S‐demethylation of 5. S‐Demethylation of 3 could also be effected with sodium methylmercaptide in methyl sulfoxide without the occurrence of annulation. In methyl sulfoxide the process of demethylation was accelerated and occurred at lower temperature.
Ring transformations of 4H‐pyrans. Pyridines from 2‐amino‐4H‐pyrans
Authors: Seoane Carlos , Soto José L. , Zamorano Pilar , Quinteiro Margarita
Published: May 2009

Ring transformations of 4H‐pyrans into pyridines are reported. Treatment of 2‐amino‐4,6‐diaryl‐3,5‐dicyano‐4H‐pyrans (I) with nitrosylsulfuric acid brings about their transformation into 3,5‐dicyano‐4,6‐diaryl‐2‐pyridones (VI) which can also be obtained from α‐benzoylcinnamonitriles (IX) and cyanoacetamide. Similarly, 2‐amino‐4,6‐diaryl‐5‐carbethoxy‐3‐cyano‐4H‐pyrans (II) lead to 4,6‐diaryl‐5‐carbethoxy‐3‐cyano‐2‐pyridones (VII). Treatment of both series of pyrans with sulfuric acid results in the formation of the corresponding 3,4‐dihydro‐2‐pyridones (IV and V). Reaction of pyrans II with ammonium acetate in acetic acid yields 2‐amino‐4,6‐diaryl‐5‐carbethoxy‐3‐cyanopyridines (XII). Pyrans I undergo an entirely different type of reaction upon treatment with this reagent leading to 2,4,6‐triaryl‐3,5‐dicyano‐1,4‐dihydropyridines (XV).
Tricyclic thiazolo[3,2‐a]thiapyrano[4,3‐d]pyrimidines and related analogs as potential anti‐inflammatory agents
Authors: Rovnyak George , Shu Virginia , Schwartz Joseph
Published: May 2009

A series of novel tricyclic thiazolo[3,2‐a]thiapyrano[4,3‐d]pyrimidines and related oxa, aza and carbo analogs of general formula 1 were prepared by a convenient addition‐cyclization reaction involving 2‐amino‐2‐thiazoline (4) and bisarylidene ketones of formula 3. Some of these compounds demonstrated antiinflammatory activity.
Synthesis of 3‐Acyl‐1,2‐benzisoxazoles
Authors: Yamamori Teruo , Hiramatsu Yoshiharu , Adachi Ikuo
Published: May 2009

A convenient method for the synthesis of 3‐acyl‐1,2‐benzisoxazoles, which are unstable toward bases, is described. Base‐catalyzed cyclization of 2‐alkyl‐ and aryl‐1,3‐dithian‐2‐yl o‐chlorophenylketoximes 4a‐1 gave 3‐(2‐alkyl‐ and aryl‐1,3‐dithian‐2‐yl)‐1,2‐benzisoxazoles 8a‐1, which were converted into the corresponding 3‐acyl‐1,2‐benzisoxazoles 1a‐1.
Synthesis and reactions of 1‐[1‐oxido‐2‐(3,4)‐pyridinyl]‐2‐methyloxiranes with nitrogen nucleophiles
Authors: Avasthi Kamlakar , Knaus Edward E.
Published: May 2009

Reaction of 2(3,4)‐pyridinecarboxaldehydes (5) with ethylidenetriphenylphosphorane afford a mixture of stereoisomers Z‐(6) and E‐1‐[2(3,4)‐pyridinyl]‐1‐propenes (7). m‐Chloroperbenzoic acid oxidation of 6 and 7 yields a 60:40 mixture of Z‐(8) and E‐1‐[1‐oxido‐2(3,4)‐pyridinyl]‐2‐methyloxiranes (9). The regiospecific reaction of Z‐isomers 8a‐c with cyclic amines as piperidine give rise to threo‐1‐hydroxy‐1‐[1‐oxido‐2(3,4)‐pyridinyl]‐2‐(1‐piperidino)propanes (10) while the E‐isomer 9a yields erythro‐11. On tho other hand, the E‐isomers 9b and 9c having 1‐oxido‐3(4)‐pyridinyl substituents afford erythro‐12 resulting from attack by piperidine at C‐1 of the oxirane. Reductive deoxygenation using 10% palladium on charcoal and hydrogen gas effectively removed the N‐oxide substituent from the threo‐10 and erythro‐11 β‐aminoalcohols. Dilute solution ir spectroscopy indicated the existance of strong intramolecular hydrogen bonding in the β‐aminoalcohols 10 and 11. The assignment of relative configuration of diastereoisomers 10 and 11 was based on the magnitude of the vicinal coupling constant J where J threo is greater than J erythro.
Thermal decomposition of 2‐amino‐3‐aziridino‐1,4‐naphthoquinones
Authors: Antonini Ippolito , Claudi Francesco , Cristalli Gloria , Grifantini Mario , Martelli Sante
Published: May 2009

The course of the thermal decomposition of various 2‐amino‐3‐substituted aziridino‐1,4‐naphthoquinones (Ia‐g) was investigated. In all the cases, the thermal decomposition gave variable amounts of 2,3‐diamino‐1,4‐naphthoquinone (II) and of substituted 1,2,3,4,5,10‐hexahydrobenzo[g]quinoxaline‐5,10‐diones (IIIa‐g) with complete stereospecificity. The decomposition of the aziridines Ib,f also gave significative amounts of 2‐amino‐3‐allylamino‐1,4‐naphthoquinones (IVb,f). In the case of 2‐amino‐3‐(2′‐phenyl‐3′‐ethylaziridino)‐1,4‐naphthoquinone (Ig), the formation of trans‐1‐phenyl‐1‐butene (V), 2‐(1‐phenylpropyl)‐1H‐naphtho‐imidazole‐4,9‐dione (VI), 2‐phenyl‐3‐ethyl‐3,4,5,10‐tetrahydrobenzo[g]quinoxaline‐5,10‐dione (VII), 2‐phenyl‐3‐ethyl‐5,10‐dihydrobenzo[g]quinoxaline‐5,10‐dione (VIII), and a mixture of cis‐ and trans‐4H‐2,3,5,6‐tetra‐hydro‐2‐phenyl‐3‐ethyl‐5‐iminonaphtho[1,2‐b]oxazin‐6‐one (IX) also occurred. Hypotheses concerning the mechanism and the steric course of this reaction are given. The reaction is a general method for the stereospecific synthesis of 2,3‐disubstituted 1,2,3,4,5,10‐hexahydrobenzo[g]quinoxalines.
Chemical constitution and activity of bipyridinium herbicides. Part XIV. Reduction potential and herbicidal activity of 4,4′‐(1,3,4‐thiadiazole‐2,5‐diyl)‐ and 4,4′‐(1,3,4‐oxadiazole‐2,5‐diyl)bis(1‐methylpyridinium) diiodides
Authors: Kennedy Debra A. , Summers Lindsay A.
Published: May 2009

The diquaternary salts 4,4′‐(1,3,4‐thiadiazole‐2,5‐diyl)bis(1‐methylpyridinium) diiodide and 4,4′‐(1,3,4‐oxadiazole‐2,5‐diyl)bis(1‐methylpyridinium) diiodide are reduced in aqueous solution in the pH range 5.4‐8.0 to radical cations at a potential (Eo) of ‐0.39 V and ‐0.48 V, respectively. Their activity as herbicides is reported.
An improved synthesis of 1‐methyl‐2,5‐piperazinedione
Authors: Harris Thomas D. , Reilly Timothy J. , Delprincipe Joseph A.
Published: May 2009

A new synthesis of 1‐methyl‐2,5‐piperazinedione in three steps starting from sarcosine is described. This method proceeds in higher overall yield (49%) than previous methods.
Pyridazines: (thiényl‐2)‐3 pyridazine, quelques (thiényl‐2)‐3 pyridazines substituées en 6 et systèmes à noyaux condensés dérivés
Authors: Bourguignon Jean , Bécue Christian , Queguiner Guy
Published: May 2009

Nous décrivons la synthèse de la (thiényl‐2)‐3 pyridazine et de quelques‐uns de ses dérivés substituée en 6 (éthoxy, hydrazino et azido). Certains de ces composés nous ont permis d'accéder à des systèmes à noyaux condensés (triazolo et tétrazolo pyridazines).
Chemistry of the phenoxathiins and isosterically related heterocycles. XV. Synthesis of 1‐nitrophenoxathiin and the relation of the 13C‐Nmr chemical shift of the alpha‐carbon to the dihedral angle
Authors: Turley James C. , Martin Gary E.
Published: May 2009

The synthesis of the previously unreported 1‐nitrophenoxathiin is described. The 13C‐nmr spectrum of the title compound is assigned based on chemical shift additivities and 1H‐13C spin‐coupling constants. From the observed 13C‐nmr chemical shift of the alpha‐carbon the title compound was predicted to have a molecular dihedral angle, Ø = 143.3°, based on a recently described interrelation between the alpha‐carbon 13C‐nmr chemical shift and the dihedral angle. Independent measurement of the dihedral angle in a crystallographic study has shown that there are two independent molecules contained in the assymetric unit which posess dihedral angles, Ø = 145.7 and 163.4°, the former in excellent agreement with the angle predicted by the assigned 13C‐nmr data.
The preparation of some biisothiazolylidenes
Authors: Clark Peter D. , Mckinnon David M.
Published: May 2009

A series of 5,5′‐biisothiazolylidines has been prepared from isothiazolidine‐5‐thiones and their ability to form charge‐transfer complexes with electron acceptors has been investigated.
A photochemical synthesis of 11H‐benzo[a]carbazole
Authors: Olsen Robert J. , Cummings O. William
Published: May 2009

11H‐Benzo[a]carbazole was prepared from 5‐acetamido‐1,2,3,4‐tetrahydronaphthalene in four steps. A Goldberg arylation followed by hydrolysis afforded N‐phenyl‐1,2,3,4‐tetrahydro‐5‐naphthylarnine (3). Photolysis of 3 produced 1,2,3,4‐tetrahydro‐11H‐benzo[a]carbazole (4) which was converted to 11H‐benzo[a]‐carbazole by dehydrogenation with chloranil.
Reissert compound studies. XL. The first monocyclic reissert compounds
Authors: Veeraraghavan Seshadri , Bhattacharjee Debkumar , Popp Frank D.
Published: May 2009

Pyridazine and pyrimidine have been reacted with trimethylsilyl cyanide and benzoyl chloride to give the first examples of Reissert compounds derived from monocyclic systems.
The unusual formation of pyrrolo[1,2‐a]pyrazines in the reaction of alkylpyrazine anions with trans‐1,2‐dichloroethylene
Authors: Houminer Yoram
Published: May 2009

The reaction of alkylpyrazine anions with trans‐1,2‐dichloroethylene produces pyrrolo[1,2‐a]pyrazines in low yields.
Ètude des reactions de nitration de l'acetamido‐3 ethyl‐9 carbazole
Authors: Lancelot Jean‐Charles , Gazengel Jean‐Marie , Robba Max
Published: May 2009

La première nitration de l'acétamido‐3 éthyl‐9 carbazole (1c) s'effectue en position 6 alors que le formamido‐3 et le N‐carbéthoxyamino‐3 éthyl‐9 carbazole (1b) et (1d) sont nitrés initialement sur le sommet 4. Le formarnido‐3 éthyl‐9 carbazole (1b) peut subir une dinitration en 4 et en 6 de měme que l'acétamido‐3 et le N‐carbethoxyamino‐3 éthyl‐9 carbazole qui donnent également des dérivés trinitrés 7b et 7c. Les structures sont établies par voie chimique et au moyen des spectres de rmn.
Functionalization of the 4(5)methyl group of imidazoles: A novel synthesis of substituted imidazoles
Authors: Webb R. Lee , Lewis Joseph J.
Published: May 2009

Acyl vinyl phosphonium salts react with amidines to form imidazolyl phosphonium salts. These imidazolyl salts can be readily converted to multifunctional imidazoles with quantitative recovery of triphenyl phosphine.
Synthesis and properties of 1‐Benzothiopyrano[2,3‐d]‐pyrimidine‐2,4‐(3H)diones (10‐thia‐5‐deazaflavins)
Authors: Yoneda Fumio , Tsukuda Kinshiro , Kawazoe Michiko , Sone Atsuko , Koshiro Akira
Published: May 2009

Treatment of 6‐arylthiouracils with the Vilsmeier reagent (dimethylformamide‐phosphorus oxychloride) gave the corresponding 6‐arylthio‐5‐formyluracils, which could alternatively be prepared by the condensation of 6‐chloro‐5‐formyluracils with thiophenols. Dehydrative cyclization of the above 5‐formyluracils with polyphosphoric acid gave 1‐benzothiopyrano[2,3‐d]pyrimidine‐2,4‐(3H)diones (10‐thia‐5‐deazaflavins). These 10‐thia‐5‐deazaflavins oxidized alcohols to give the corresponding carbonyl compounds with the aid of strong base, and they were hydrogenated to 1,5‐dihydro‐10‐thia‐5‐deazaflavins. Treatment of 10‐thia‐5‐deazaflavins with concentrated aqueous potassium hydroxide led to the exclusive formation of 1,5‐dihydro‐10‐thia‐5‐deazaflavins and 1,5‐dihydro‐10‐thia‐5‐deazaflavin‐5‐ones via intermolecular oxidation‐reduction (disproportionation) between initially formed 1,5‐dihydro‐5‐hydroxy‐10‐thia‐5‐deazaflavins and unchanged 10‐thia‐5‐deazaflavins.
Amination of 2,6‐ and 2,7‐Naphthyridine. An NMR study on σ‐Adducts of heterocyclic systems with amide ions
Authors: Van Den Haak Henk J. W. , Van Der Plas Henk C. , Van Veldhuizen Beb
Published: May 2009

A facile synthesis of 2,6‐naphthyridine is described. Both 2,6‐ and 2,7‐naphthyridine undergo with potassium amide under kinetically and thermodynamically controlled conditions σ‐adduct formation at position 1. Chichibabin amination of 2,6‐naphthyridine yields 1‐amino‐2,6‐naphthyridine in 54% yield.
Synthesis of bridgeheaded nitrogen systems. s‐triazolo[4,3‐b]‐as‐triazine, s‐triazolo[4,3‐d]‐as‐triazine and s‐triazolo[3,4‐b]‐1,3,4‐Thiadiazole ring systems
Authors: Sasaki Tadashi , Ito Eikoh
Published: May 2009

By the reactions of hydrazino‐as‐triazines (1a‐d and 5) with cyanogen bromide were synthesized s‐triazolo‐as‐triazines (2a‐d) and (6). Likewise, similar reactions of amino‐s‐triazolethiols (7a‐e) gave s‐triazolo‐1,3,4‐thiadiazoles (8a‐e). Compound 2a was brominated to 2g.
Synthèse d'acétyl‐6 et benzoyl‐6 indoles
Authors: Ta Kim Phieo , Guilard Roger , Dodey Pierre , Sornay Roland
Published: May 2009

La synthèse d'acétyl‐6 et benzoyl‐6 indoles a été réalisée via la réaction de Hemetsberger. Quelques aspects de leur réactivité sont envisagés.
Conversion of 3,7‐Dialkoxy‐4H,8H‐benzo[l,2‐c:4,5‐c']diisoxazole‐4,8‐dione into new heterocyclic systems
Authors: Neidlein R. , Throm S.
Published: May 2009

Treatment of 1a or 1b with concentrated acids yielded the acid 3, with alkali hydrogen carbonates the sodium salt 7 and the potassium salt 8; by reacting with phosphorus pentachloride the vinylogous acid chloride 9 was isolated. Reactions of 9 with amines such as N‐nucleophiles led to the corresponding amides 10, 11, 14, 15, and with alcohols such as O‐nucleophiles to the corresponding alkoxyderivatives 16a, 16b, which are isomeric compounds to 1a, 1b and 2a, 2b.
The route of action of sodium methoxide on 5‐Arylmethylene‐2‐Disubstituted amino‐4‐oxo‐2‐thiazolines
Authors: Omar M. T. , Kasem M. A.
Published: May 2009

5‐Arylmethylene‐2‐disubstituted amino‐4‐oxo‐2‐thiazolines 1a‐d reacted with six and two moles of sodium methoxide to give the 2‐mercaptocinnamic acid esters 6 and mixtures of 2,2‐dimethoxy‐4‐oxothiazolidines 4 and 2,4‐dioxothiazolidines 5, respectively. The intermediate mixture of the sodium salt of 5‐aryImethylene‐2,2‐dimethoxy‐4‐oxothiazolidines 3 in the above mentioned transofrmations was established. The structures of 3, 4, 5 and 6 were based on analytical and spectral evidence. The route of conversion of 1 into 3, 4,5 and 6 was presented and discussed.
Synthesis of some 2,3‐Dihydro‐11bH‐thiazolo[3,2‐d][1,4]benzoxazepin‐5‐(6H)one derivatives. A new heterocyclic ring system
Authors: Torrini Ines , Paradisi Mario Paglialunga , Romeo Aurelio
Published: May 2009

Condensation of (S)‐penicillamine methyl or ethyl ester hydrochloride with salicylaldehyde and its C‐5 derivatives, provided the diastereomeric thiazolidine derivatives 1 and 2. The resulting amino function was acylated to afford the amides 3 and 4. Cyclization of the latter led to the 2,3‐dihydro‐11bH‐thiazolo[3,2‐d]‐[1,4]benzoxazepin‐5‐(6H)ones 5 and 6. Conformational data for these heterocyclic compounds are discussed.
Synthesis of triphenyleno[b]thiophenes
Authors: Pratap Ram , Lee Milton L. , Castle Raymond N.
Published: May 2009

The synthesis of all the isomers of triphenyleno[b]thiophenes namely, triphenyleno[l,2‐b]thiophene, triphenyleno[2,1‐b]thiophene and triphenyleno[2,3‐b]thiophene is described.
Synthesis of bisimines of pyrene and dibenz[a,h]anthracene
Authors: Yona Irene , Blum Jochanan
Published: May 2009

The preparation of 3b,4a,7b,8a‐tetrahydro‐4H,8H‐pyreno[4,5‐b:9,10‐b']bisazirine and of 1a,6b,7a,12b‐tetrahydro‐1H,7H‐dibenz[3,4:7,8]anthra[1,2‐b:5,6‐b']bisazirine is described. The corresponding diepoxides were reacted with sodium azide in aqueous acetone and the mixtures of trans‐azido alcohols, so formed, were cyclized by tri‐n‐butylphosphine.
Reaction of phthaloylasparic anhydride with o‐phenylenediamine in solution and spectral analysis of the reaction products
Authors: Yang Chin‐Ping
Published: May 2009

The ring‐opening addition reaction of phthaloylasparic anhydride (I) with o‐phenylenediamine (II) in a solution is affected by the polarity of the solvent used. At the molar ratio of 1:1, I and II undergo a β‐oriented ring‐opening reaction in polar solvents, such as DMF, DMAC, and DMSO; while in weaker polar solvents, such as dioxane and tetrahydrofuran, α‐orientation predominates. By heating in a solvent mixture of DMF and xylene, the ring‐opening products undergo condensation, and are converted into two isomers. One is methanol soluble 3‐phthalimido‐3‐(2)benzimidazolylpropanoic acid (V) resulting from the α‐oriented ring‐opening reaction, the other is the sparingly soluble (in DMF) 2‐phthalimido‐3‐(2)benzimidazolylpropanoic acid (VI) resulting from the β‐oriented ring‐opening reaction. The soluble V can be precipitated as cotton‐like crystals from methanol and chloroform. When treated with acetic anhydride, V and VI are converted to other isomers, namely 3‐phthalimidobenzimidazopyrrolone (VII) and 2‐phthalimidobenzimidazopyrrolone (VIII). The isomers were identified by spectral analysis.
A novel synthesis of theophylline derivatives
Authors: Yoneda Fumio , Koga Ryosuke
Published: May 2009

Treatment of 6‐amino‐5‐arylazo‐1,3‐dimethyluracils with ethyl propiolate gave the corresponding Michael‐type adducts, 5‐arylazo‐1,3‐dimethyl‐6‐ethoxycarbonylvinylaminouracils, which on treatment with a mixture of hydrochloric acid and acetic acid caused the acid‐catalyzed rearrangement accompanied with rearrangement to give rise to the corresponding 8‐anilinomethyltheophylline derivatives.

In the case that the arylazo group possesses an electron‐releasing substituent such as methoxy, the reaction proceeded in a different way to afford 1,2‐bis(theophyllin‐8‐yl)ethane.

The presumable reaction mechanisms for the above purine syntheses were proposed.
Aromatization of aliphatic compounds. VII. Benzofuranones, indoles and oxindoles
Authors: Giannangeli M. , Baiocchi L.
Published: May 2009

2(4H)‐5,6‐Dihydrobenzofuranones 3 gave, when treated with pyridine hydrochloride at 200°, the corresponding arylacetic acids 1 in good yields, whereas the aza analogues, the tetrahydrooxindoles 6 gave indoles in poor yields. The oxidation products of 3 (11 and 13) and of 6 (12, 14 and 15) gave, with the same reagent, benzofuranones and oxindoles, respectively, both in good yields.
Imino‐bridged heterocycles. II. Regiospecific synthesis of the 11H‐benzo[5,6]cyclohepta[1,2‐c]pyridin‐6,11‐imine and 5H‐benzo[4,5]cyclohepta[1,2‐b]pyridin‐5,10‐imine systems
Authors: Brenner Daniel G. , Halczenko Wasyl , Shepard Kenneth L.
Published: May 2009

Regiospecific synthetic pathways for two of the eight isomeric benzocycloheptapyridinimines have been developed based upon intramolecular acid catalyzed additions between an amine function and an internal olefin. The requisite amines were generated from known tricyclic ketones by ketimine formation followed by sodium borohydride reduction.
Synthesis and xanthine oxidase inhibitory activity of 4,6‐disubstituted 1‐p‐chlorophenylpyrazolo[3,4‐d]pyrimidines
Authors: Senga Keitaro , Robins Roland K.
Published: May 2009

Several 4,6‐disubstituted 1‐p‐chlorophenylpyrazolo[3,4‐d]pyrimidines were prepared from 4,6‐dichloro‐1‐p‐chlorophenylpyrazolo[3,4‐d]pyrimidine and their xanthine oxidase inhibitory activity were tested in vitro.
On the aromaticity of porphin
Authors: Nudy Louis R. , Coffey Joan C. , Longo Frederick R. , Kim Jean B.
Published: May 2009

We have undertaken a study of the bromination of porphin. We have learned contrary to literature reports, that bromine (in chloroform) attacks porphin preferentially at the meso position and that bromination of this meso monobromoporphin produces a single dibromo product, namely 5, 15‐dibromoporphin. Our results are interpreted in terms of the aromaticity of the different peripheral carbon atoms.
Some sulfur‐containing quinoxalines
Authors: Campaigne E. , Mclaughlin Astley R.
Published: May 2009

A series of quinoxalines having oxygen, chlorine or sulfur substituted at the 2‐positio and long‐chain alkyl, alkylthio, arylthio, alkylthioalkyl or arylthioalkyl groups at the 3‐position have been synthesized.
Studies related to the total synthesis of pentostatin. Approaches to the synthesis of (8R)‐3,6,7,8‐tetrahydroimidazo‐[4,5‐d][1,3]diazepin‐8‐ol and N‐3 alkyl congeners
Authors: Baker David C. , Putt Sterling R. , Showalter H. D. Hollis
Published: May 2009

A number of synthetic approaches to the (8R)‐3,6,7,8‐tetrahydroimidazo[4,5‐d][1,3]diazepin‐8‐ol ring system (3) of pentostatin (1) are reported. These involve the synthesis of a number of 4‐C‐derivatives of N‐alkyl‐5‐amino‐ and 5‐nitro‐1H‐imidazoles derived from 4‐methyl‐5‐nitro‐1H‐imidazole.
Synthesis of S‐5‐pyrrolo[2,3‐b]pyridinemethyl and S‐5‐ and S‐6‐pyrrolo[2,3‐d]pyridinemethyl derivatives of 5′‐deoxy‐5′‐thioadenosine
Authors: Benghiat Eric , Crooks Peter A.
Published: May 2009

Reaction of 5‐dimethylaminomethylpyrrolo[2,3‐b]pyridine methiodide or 5‐dimethylaminomethylpyrrolo[2,3‐d]pyrimidin‐4‐one methiodide with 5′‐deoxy‐5′‐S‐thioacetyl‐N6‐formyl‐2′,3′‐O‐isopropylideneadenosine in ethanolic sodium hydroxide solution, followed by deprotection of the resulting thioether in 80% formic acid, afforded 5′‐deoxy‐5′‐(5‐pyrrolo[2,3‐b]pyridinemethylthio)adenosine or 5′‐deoxy‐5′‐[5‐(pyrrolo[2,3‐d]pyrimidin‐4‐one)methylthio]adenosine, respectively. Similarly, the metiodide salt of the iso‐gramine analog, 2‐amino‐6‐dimethylaminomethylpyrrolo[2,3‐d]pyrimidin‐4‐one afforded 5′‐deoxy‐5′‐[6‐(2‐aminopyrrolo[2,3‐d]pyrimidin‐4‐one)methylthio]adenosine.
Synthesis of chalcogeno lactones. II. 3, 4‐dihydro‐1 H‐2‐benzothiin‐3‐one, 3,4‐dihydro‐1H‐2‐benzoselenin‐3‐one and 3,4‐dihydro‐1H‐2‐benzotellurin‐3‐one
Authors: Lemaire Ch. , Luxen A. , Christiaens L. , Guillaume M.
Published: May 2009

The synthesis of 3, 4‐dihydro‐1H‐benzothiin‐3‐one and its selenium and tellurium analogs is reported from o‐bromomethylphenylacetyl chloride and sodium hydrogen chalcogenates, via phase‐transfer catalysis.
Synthesis and spectral studies of 2‐mercapto‐benzimidazole derivatives. II
Authors: Suri O. P. , Khajuria R. K. , Saxena D. B. , Rawat N. S. , Atal C. K.
Published: May 2009

This communication describes synthesis and spectral data of new 2‐mercaptobenzimidazole derivatives.
Synthesis and structural analysis of a 2,5‐diazabicyclo [4.1.0]heptane
Authors: Majchrzak Michal W. , Kotelko Antoni , Lambert Joseph B.
Published: May 2009

Synthesis of a new heterocyclic system, 2, 5‐diazabicyclo [4. 1. 0] heptane, substituted on nitrogen, has been achieved by the reaction of the disodium or dipotassium salt of cis‐1, 2‐ (arenesulfonamido) cyclopropane with ethylene bromide. Analysis of the 1H magnetic resonance spectrum demonstrated that this bicyclic system exists as a mixture of interconverting enantiomeric half‐chair conformers.
The synthesis of the monomethylbenzo[2,3]phenanthro‐[4,5‐bcd]thiophenes
Authors: Sugiura Michiharu , Tedjamulia Marvin L. , Tominaga Yoshinori , Castle Raymond N. , Lee Milton L.
Published: May 2009

The synthesis of the potentially mutagenic 1‐methyl‐ (11), 3‐methyl‐ (12), 4‐methyl‐ (21), 5‐methyl‐ (27), 7‐methyl‐ (58), 8‐methyl‐ (61), 9‐methyl‐ (59) and 10‐methylbenzo[2,3]phenanthro[4,5‐bcd]thiophene (60) is reported.
Photoaddition of 2,3‐dimethylmaleic anhydride to selenophthene
Authors: Pacheco D. , Rivas C. , Vargas F.
Published: May 2009

As a continuation of studies carried out in this laboratory [2] on the properties of selenophene and its methyl derivatives as substrates for excited carbonyl compounds and for methylmaleic anhydride derivatives in photosensitized reactions benzo[b]selenophene and selenophthene were tested as well. The latter were found to be inert in oxetane formation but good substrates in photosensitized reactions.
Dipole moments and conformation of 1‐(N,N‐Diaroyl)amino‐1,2,3‐triazoles
Authors: Rodios Nestor A. , Coutsolelos Athanasios G.
Published: May 2009

Experimental dipole moments of a number of the title compounds are given and theoretical dipole moments have been calculated by vector addition for all possible conformations. The graphical method has been used to correlate experimental and calculated dipole moments. The more probable conformation in solution of the title compounds and especially of the imide group is proposed.
Synthesis of 4‐amino‐6‐phenyl‐3(2H)‐pyridazinones: A general procedure
Authors: Sircar Ila
Published: May 2009

A method for the synthesis of 3,4‐dichloro‐6‐phenylpyridazine 5 was described. The compound 5 was used as an intermediate for the synthesis of a series of 4‐amino‐6‐phenyl‐3(2H)‐pyridazinones.
Thiamorphinans. I
Authors: Sauter Fritz , Stanetty Peter , Hetzl Ernst , Fuhrmann Ferdinand
Published: May 2009

The present paper deals with the synthesis of 5,5a,6,7,8,9‐hexahydro‐5,9a‐iminoethano‐4H‐naphtho[2,1‐b] ‐thiophenes (I) as derivatives of the first of three novel isomeric S‐heterocycles with morphinan‐like structure (“thiamorphinans”).
Displacement reactions of 5‐chloro‐4‐phenylazopyrazoles
Authors: Eid El‐Mohamady E. , Bonner The Late Trevor G. , Lewis David
Published: May 2009

3‐Methyl or 3‐phenyl‐5‐chloro‐1‐phenyl‐4‐phenylazopyrazole with primary amines, sodium polysulfide and sodium azide yielded amines, disulfides and 2,4‐dihydropyrazolo[3,4‐d]‐1,2,3‐triazoles respectively. 4‐Amino‐5‐anilino‐1,3‐diphenylpyrazole was also prepared and characterized.
Polycyclic nitrogen compounds. Part II. Tricyclic quinoxalinones and their 4‐ or 6‐aza analogues
Authors: Adegoke E. A. , Alo Babajide
Published: May 2009

1,2,3,3a‐Tetrahydro‐9‐nitropyrrolo[1,2‐α]quinoxalin‐4‐one and 7,8,9,10‐tetrahydro‐3‐nitropyrido[1,2‐α]quin‐oxalin‐6‐one (V‐VI) were reduced and deaminated to give new parent tricyclic quinoxalinone skeletons I‐II. The latter compounds were identical with the tricycles obtained by an unambiguous independent synthesis. New 6‐aza‐1,2,3,3a‐tetrahydropyrrolo[1,2‐α]quinoxalin‐4‐one (III) and 4‐aza‐7,8,9,10‐tetrahydropyrido[1,2‐α]‐quinoxalin‐6‐one (IV) were prepared by selective hydrogen transfer reductive cyclisation of esters of N‐(2‐nitro‐3‐pyridyl)pyrrolidine‐2‐carboxylic acid and N‐(2‐nitro‐3‐pyridyl)piperidine‐2‐carboxylic acid (Xb and XIb) respectively.
Some observations concerning the lactonization of 3‐aroylpropionic acids
Authors: Tsolomitis A. , Sandris C.
Published: May 2009

The ease of lactonization of the γ‐keto acids ArCOCH2CH2COOH is shown to depend on the nature of the aryl group: the presence of electron‐releasing substituents on the aryl group results in a more rapid reaction as compared to the presence of electron‐withdrawing substituents. The case of this cyclodehydration reaction is also shown to depend on the reagent used: acetic anhydride‐sulfuric acid is a more drastic reagent than acetic anhydride alone. Acetyl chloride, a reagent of intermediate reactivity in this reaction, is shown to yield easily the corresponding 5‐arylfuran‐2(3H)‐ones in satisfactory yields.
Reaction of substituted sulfenes with N,N‐disubstituted α‐amino‐methyleneketones. II. Synthesis of N,N‐disubstituted cis and trans 4‐amino‐3‐chloro‐3,4,5,6,7,8‐hexahydro‐1,2‐benzoxathiin 2,2‐dioxides, and 4‐amino‐5,6,7,8‐tetrahydro‐1,2‐benzoxathiin 2,2‐dioxides
Authors: Bargagna Alberto , Schenone Pietro , Bignardi Gaetano , Longobardi Mario
Published: May 2009

The polar 1,4‐cycloaddition of chlorosulfene (generated in situ from chloromethanesulfonyl chloride and triethylamine) to N,N‐disubstituted (E)‐2‐aminomethylenecyclohexanones I gave mixtures of N,N‐disubstituted cis and trans 4‐amino‐3‐chloro‐3,4,5,6,7,8‐hexahydro‐1,2‐benzoxathiin 2,2‐dioxides III and IV, except for N,N‐diphenyl enaminone which did not react. Only compounds IV could be separated from these mixtures by silica gel chromatography, with the exception of the piperidino adducts (III + IV)d, from which also IIId could be obtained pure. Compounds IV or mixtures III + IV were dehydrochlorinated with DBN in refluxing benzene to afford N,N‐disubstituted 4‐amino‐5,6,7,8‐tetrahydro‐1,2‐benzoxathiin 2,2‐dioxides V in satisfactory yields. Structural and conformational features of compounds III, IV and V were determined from uv, ir and nmr spectral data.
1,3‐cycloaddition of substituted benzonitrile oxides to aliphatic nitriles. The kinetic effect of substituents
Authors: Beltrame Paolo , Gelli Gioanna , Loi Aldo
Published: May 2009

A previous study of the reaction of aromatic nitrile oxides with simple aliphatic nitriles, with the formation of 3,5‐disubstituted 1,2,4‐oxadiazoles, has been extended to a larger number of nitrile oxides. Sixteen new oxadiazole derivatives have been prepared and characterized. Cycloaddition rates have been measured in the temperature range from 50 to 80°. When considering the effect of substituents on the aromatic ring, roughly V‐shaped Hammett plots have been obtained, as already observed for other concerted 1,3‐cycloadditions.
Reactions with diazoazoles. Part VI. Unequivocal synthesis of 3‐methyl‐3h‐azolotetrazoles. Correction of the formerly described 3‐methylazolotetrazoles in favour of mesoionic 2‐methylazolotetrazoles
Authors: Ege Günter , Heck Reinhard , Gilbert Karlheinz , Irngartinger Hermann , Huber‐Patz Ursula , Rodewald Hans
Published: May 2009

3‐Methyl‐3H‐pyrazolo[1,5‐d]tetrazoles 2 and 3‐methyl‐6‐phenyl‐3H‐1,2,4‐triazolo[1,5‐d]tetrazole (4) have been unequivocally synthesized by annulation of the tetrazole moiety to the pyrazole resp. 1,2,4‐triazole system. The constitution of some N‐methyl substituted azolotetrazoles, formerly described as 3‐methyl‐3H‐pyrazolo[1,5‐d]tetrazoles 2, 3‐methyl‐6‐phenyl‐3H‐1,2,4‐triazolo[1,5‐d]tetrazole (4) and 1‐methyl‐6‐phenyl‐1H‐1,2,4‐triazolo[4,3‐d]tetrazole (5), has to be revised in favour of the corresponding mesoionic 2‐methyl derivatives 2′, 4′, 5′. The structures of 3‐methyl‐3H‐ as well as of 2‐methyl‐2H‐pyrazolo[1,5‐d]tetrazole derivatives 2a, 2c, 2′a have been determined by X‐ray analyses. The azapentalenic system is aromatic in all three measured compounds and mesoionic in the case of the 2‐methyl‐2H‐ substitution pattern. The phenyl and ester substituents are coplanar with the azapentalene system. 3‐, 2‐, and 1‐Methylpyrazolo[1,5‐d]tetrazoles exhibit different behaviour when allowed to react with stannous chloride or sodium ethoxide. Azolotetrazoles with a methyl substituent at N‐1, N‐2 or N‐3 of the tetrazole moiety can be distinguished by a combination of 1H and 13C nmr with respect to the chemical shifts of the N‐methyl group and the bridgehead carbon. Results of semiempirical calculations of the pyrazolo[1,5‐d]tetrazole anion and of its N‐methyl derivatives are discussed.
Angular heterocycles. Utilization of arylaminonaphthoquinones in the synthesis of benzophenothiazines
Authors: Agarwal Nand L. , Atal Chand K.
Published: May 2009

Substituted 6‐ethoxyanilino‐5H‐benzo[a]phenothiazin‐5‐ones (3a‐f) were synthesized by the cyclocondensation of 2‐chloro‐3‐ethoxyanilino‐1,4‐naphthoquinones with zinc mercaptides of 2‐aminothiophenol in pyridine. The nmr, ir and mass spectral data are presented and discussed.
Synthesis of some new pyrimido[1,6‐a]pyrimidines
Authors: Pegiadou‐Koemtjopoulou S. , Tsatsaronis G.
Published: May 2009

4‐Amino‐5‐arylpyrimidines 1 react with diethyl alkylmalonates 2 to give pyrimido[1,6‐a]pyrimidines 4 in satisfactory yields. A possible mechanistic scheme and the spectral data of the reaction products are discussed.
Total synthesis of 4,5,7a,8‐tetrahydro‐1,2‐dimethoxyphenanthro[10,1‐bc]‐azepin‐6(7H)‐one: A photochemical approach
Authors: Jensen Bruce L. , Chockalingam Kannappan
Published: May 2009

The total synthesis of a novel benzazepine, 4,5,7a,8‐tetrahydro‐1,2‐dimethoxyphenanthro[10,1‐bc]azepin‐6(7H)‐one is described. Of crucial importance to the preparation of this material was a regiospecific Beckmann rearrangement reaction and the development of an aryl‐aryl linkage by a photochemically induced coupling. Details of successful and attempted methodology are reported.
Proton‐ionizable crown compounds. 4. New macrocyclic polyether ligands containing a triazole subcyclic unit
Authors: Bradshaw Jerald S. , Nielsen Ralph B. , Tse Pui‐Kwan , Arena Giuseppi , Wilson Bruce E. , Dalley N. Kent , Lamb John D. , Christensen James J. , Izatt Reed M.
Published: May 2009

A series of macrocyclic polyether (crown) ligands containing the proton‐ionizable s‐triazole subcyclic unit were prepared by reacting the 1‐THP blocked 3,5‐bis(chloromethyl)‐1H‐1,2,4‐triazole with various oligoethylene glycols. The starting bis(chloromethyl)triazole is a vessicant and must be used with caution. Triazolo‐18‐crown‐6 (5) formed stable complexes with barium, strontium, copper and benzylammonium cations but not with potassium or lithium. The crystal structure of 5 showed the triazole proton to be on nitrogen 3 which is outside the macroring cavity.
Synthesis and spectral properties of optically active 2‐ethylidene‐1,5‐dimethyl‐3,3‐diphenylpyrrolidine: Primary methadone metabolite
Authors: Brine George A. , Boldt Karl G. , Bondeson Virginia C. , Carroll F. Ivy
Published: May 2009

The synthesis of the optical isomers of 2‐ethylidene‐1,5‐dimethyl‐3,3‐diphenylpyrrolidine is reported. The1H‐nmr analysis suggested that the free bases exist predominantly in an enamine form and the corresponding perchlorate salts in an iminium form. Optical studies showed that the free bases exhibit Cotton effects in the 400–230 nm region and that these Cotton effects are consistent with a fairly rigid enamine structure.
Oxidation of heterocyclic nitrogen Ylids to nitro heterocycles. Comparison of a sulfilimine and a phosphine imine
Authors: Coburn Michael D.
Published: May 2009

Oxidation of 3‐amino‐4‐(4‐chlorophenyl)furazan (1) with peroxytrifluoroacetic acid (ptfa) gave azoxy(4‐chlorophenylfurazan) (6) as the major product along with a small amount of 3‐(4‐chlorophenyl)‐4‐nitrofurazan (5). The dimethylsulfilimine 2 derived from 1 gave near quantitative yields of 5 when subjected to oxidation with either ptfa or m‐chloroperoxybenzoic acid (mcpba). In contrast, both the trioctylphosphine imine 3 and the triphenylphosphine imine 4 derived from 1 were oxidized by mcpba to give 6 as the exclusive product.
Synthesis of amino substituted 4‐oxo‐1,2,3,4‐tetrahydropyridines from arylhydrazones and methyl acrylate
Authors: Barluenga J. , Palacios F. , Viña S. , Gotor V.
Published: May 2009

Arylhydrazones react with methyl acrylate in the presence of aluminium chloride to afford amino substituted 4‐oxo‐1,2,3,4‐tetrahydropyridines.
On the amination of pteridines by liquid ammonia‐potassium permanganate
Authors: Sladowska H. , De Meester J. W. G. , Van Der Plas H. C.
Published: May 2009

7‐Phenyl‐, 7‐(p‐methoxyphenyl)‐, 7‐methyl‐, 7‐t‐butyl‐, 6,7‐diphenyl‐, 6,7‐dimethyl‐ and 2‐phenylpteridine are converted in good yields into their respective 4‐amino compounds, when they are dissolved in liquid ammonia (‐40°) and potassium permanganate is added to the solution. Increase of the temperature of the amino‐oxidation did not change the position of substitution, the yields are however lower. The intermediary of 4‐aminodihydropteridines in these reactions has been proved by 1H nmr spectroscopy.
Preparation of monoacylpyrazines
Authors: Houminer Y. , Southwick E. W. , Williams D. L.
Published: May 2009

Homolytic acylation of pyrazine and alkylpyrazines by aldehydes, as a source of an acyl radical, gives mainly monoacylation products. The reactions proceed in reasonable yields and provide a new route to pyrazine ketones.
Synthesis of 1,8‐naphthyridine derivatives. Potential antihypertensive agents. 1
Authors: Ferrarini Pier Luigi , Mori Claudio , Primofiore Giampaolo
Published: May 2009

Reaction of substituted 7‐chloro‐1,8‐naphthyridines with N‐carbethoxypiperazine gave in good yields the corresponding 7‐(4‐carbethoxypiperazin‐1‐yl)‐1,8‐naphthyridines V as potential antihypertensive agents.
Chlorimine formation and deamination of the model nucleobase 1‐methylcytosine
Authors: Beyerle‐Pfnür Rut , Lippert Bernhard , Schöllhorn Helmut , Matischok Petra , Thewalt Ulf
Published: May 2009

Treatment of the model nucleobase 1‐methylcytosine with chlorine in aqueous solution gives, depending on the reaction conditions, 5‐chloro‐1‐methylcytosine (3) or its hemiprotonated form 2, 5,5‐dichloro‐6‐hyd‐roxy‐5,6‐dihydro‐4‐chlorimino‐1‐methylpyrimidin‐2‐one (5), and 5,5‐dichloro‐6‐hydroxy‐5,6‐dihydro‐1‐methyl‐uracil (4). While substitution of H5 of 1‐methylcytosine by chlorine giving 2 and 3, and subsequent addition of hypochlorous acid to the 5,6‐double bond is not unexpected, chlorination of the exocyclic amino group 5 and deamination to give 4 is novel. The X‐ray structures of 4 and 5 are reported.
Etude de la décomposition thermique d'azido dithiényl‐1,2 éthènes et éthanes
Authors: Farnier Michel , Brost Michèle , Hanquet Bernard , Guilard Roger
Published: May 2009

La décomposition thermique des azido dithiényl‐1,2‐éthènes 1 conduit aux thiényl 4H‐thiéno[3,2‐b]pyrroles 3. Lorsque la disubstitution thiophénique porte sur les positions 3 et 4, la fonction azide des dérivés 2 est alors transformée en amine. Par contre, seuls les azido dithiényl‐1,2 éthanes 7 livrent après cyclisation les thiényl di‐hydro‐5,6 4H‐thiéno[3,4‐b]pyrroles 8. La structure des produits isolés est établie sur la base des données rmn 1H, ir et de spectrométrie de masse.
Synthèse d'azido dithiényl‐1,2 éthènes et éthanes
Authors: Farnier Michel , Brost Michèle , Hanquet Bernard , Guilard Roger
Published: May 2009

Deux modes aisés de préparation d'azido dithiényl‐1,2 éthènes sont décrits. La synthèse d'azido dithiényl‐1,2 éthanes est réalisée via la métallation (n‐Buli) suivie de l'action du tosylazide sur des bromo dithiényl‐1,2 éthanes. Les structures des dérivés isolés sont établies sur la base des données rmn 1H, ir et de spectrométrie de masse.
Reactions of ketenes. XX. Phenylketene dimethylacetal as synthon for the introduction of functionalized phenylethyl units
Authors: Graziano M. Liliana , Iesce M. Rosaria , Scarpati Rachele
Published: May 2009

Phenylketene dimethylacetal (1) reacts with the α‐diazoketones to give the dihydrofurans 6. These compounds, as cyclic ortho esters, can undergo dealcoholation into the furans 2 and hydrolysis into the γ‐ketoesters 3 and into the γ‐ketoacids 4. Cyclopropane acetal 8, obtained starting from acetal 1 and ethyl diazoacetate, by heating leads quantitatively to functionalized ester 9. These synthetic methods enlarge the sphere of applicability of the electron‐rich alkene 1 as synthon in organic synthesis.
Pyridinethiones. XI. Diastereoselective aldol condensations with 2(1H)‐pyridones, 2(1H)‐pyridinethiones, and the crystal structure of 3‐(1‐hydroxy‐2‐methyl‐3‐oxo‐3‐(4‐chlorophenyl)propyl‐1‐isoprpyl‐2(1H)‐pyridinethione
Authors: Becher Jan , Asaad Fahmy M. , Johansen Tea , Hansen Jesper , Larsen Sine , Hansen Flemming
Published: May 2009

Aldol condensation of 3‐formyl‐2(1H)‐pyridinethiones and the corresponding pyridones with ketones such as acetophenones in aqueous base yields 3‐hydroxy‐1‐propanones in high yields. Reaction with propiophenone showed this reaction to be highly diastereoselective as only the erythro‐isomer is formed at room temperature. This assignment was based on an X‐ray crystallographic investigation of the compound given in the title. Aldol condensations of a number of related 3‐acetyl‐2(1H)‐pyridinethiones with benzaldehyde yielded the corresponding trans‐vinyl ketones.
Synthesis and thermal rearrangement of allylic 3,5,6‐trimethyl‐2‐pyrazinylacetates: A heterocyclic carroll rearrangement
Authors: Podraza Kenneth F.
Published: May 2009

The synthesis of allylic 3,5,6‐trimethyl‐2‐pyrazinylacetates 2–4 has been achieved by the reaction of 3,5,6‐trimethyl‐2‐pyrazinylacetic acid lithium salt (1) with phenyl dichlorophosphate followed by addition of the allylic alcohol. On thermolysis, the allylic β‐heteroaromatic esters underwent a rearrangement, analogous to the Carroll rearrangement, to generate the corresponding γ,δ‐unsaturated heteroaromatic compound. The configuration of the double bond formed in the product was the E‐isomer. The rate of the rearrangement was dependent on the substitution pattern of the allylic portion of the molecule with 4>2>3. The ester enolate version of the heterocyclic Carroll rearrangement was investigated with 2, however these conditions did not promote the rearrangement.
Reactivity of pyrazolo[4,3‐c][1,2,5]oxadiazin‐3(5H)‐ones toward C‐nucleophiles: Synthesis of pyrazolo[3,4‐b]pyrazines
Authors: Giori P. , Veronese A. C. , Poli T. , Vicentini C. B. , Manfrini M. , Guarneri M.
Published: May 2009

The reaction of pyrazolo[4,3‐c][1,2,5]oxadiazin‐3(5H)‐ones 1 with carbanions prepared in situ from compounds containing an activated methylene group afforded pyrazolo[3,4‐b]pyrazines 4–13 in good yields. The possible reaction mechanism is proposed and discussed.
Synthesis of benzophenothiazinone derivatives from 2,3,5‐trisubstituted‐1,4‐naphthoquinones with 2‐aminothiophenol
Authors: Nan'Ya Seiko , Maekawa Eturǒ , Kang Wen‐Bing , Ueno Yoshio
Published: May 2009

The 1‐substituted‐5H‐benzo[2,3‐a]phenothiazin‐5‐one, 4‐substituted‐5H‐benzo[6,5‐a]phenothiazin‐5‐one and 6‐substitutedbenzo[a][1,4] benzothiazino[3,2‐c]phenothiazine derivatives were prepared by the condensation of 5‐substituted‐2,3‐dichloro‐1,4‐naphthoquinones with 2‐aminothiophenol. Reduction, acetylation and dehalogenation of the resulting compounds were carried out and the structures of the products were inferred from comparison with the authentic compound.
Synthesis of 9,10,12,13,14,14a‐hexahydrodibenzo[f,h]pyrrolo‐[2,1‐a]isoquinoline
Authors: Copado C. Rodolfo , Grande G. Mercedes T. , Trigo Gregorio G. , Söllhuber K Mónica M.
Published: May 2009

The synthesis of 9,10,12,13,14,14a‐hexahydrodibenzo[f,h]pyrrolo[2,1‐a]isoquinoline6has been accomplished by a sequence involving as a key step the Friedel‐Crafts intramolecular acylation of the amino acid9to the corresponding pentacyclic aminoketone10. Compounds7, 11and12showed a significant protein synthesis inhibitory effect.
A facile one step synthesis of novel ethyl 2,6‐bis(trifluoromethyl)‐4‐hydroxypyrimidine‐5‐carboxylate
Authors: Sing Y. Larry , Lee Len F.
Published: May 2009

Trifluoroacetonitrile was condensed with diethyl malonate to give a novel ethyl 2,6‐bis(trifluoromethyl)‐4‐hydroxypyrimidine‐5‐carboxylate (2) in 88% yield. Derivations of 2 are also described.
A novel synthesis of 3‐bromo‐1,2,4‐oxadiazoles
Authors: Humphrey Guy R. , Wright Stanley H. B.
Published: May 2009

A novel synthesis of 3‐bromo‐1,2,4‐oxadiazoles by 1,3‐dipolar cycloaddition between bromocyanogen oxide and alkyl and aryl nitriles is described.
O‐Alkylations of pyridoxine and pyridoxamine
Authors: Ueda Taisei , Nakaya Kenji , Nagai Shin‐Ichi , Sakakibara Jinsaku
Published: May 2009

O‐Alkylations of pyridoxine 1 and pyridoxamine 5 were carried out in acetone in the presence of sodium ethoxide and potassium iodide to give 5‐alkoxy‐6‐methyl‐3,4‐(bishydroxymethyl)pyridines 2a‐j and 5‐alkoxy‐4‐aminomethyl‐6‐methyl‐3‐hydroxyrnethylpyridines 6a‐e.
“One pot” synthesis of 2‐substituted 9‐(2′‐hydroxy‐3′‐aminopropyl)‐8‐azahypoxanthines and 8‐azaadenines (5‐substituted 3‐(2′‐hydroxy‐3′‐aminopropyl) 7‐amino and 7‐hydroxy‐3H‐1,2,3‐triazolo[4,5‐d]pyrimidines)
Authors: Biagi G. , Franchi M. , Giorgi I. , Livi O. , Scartoni V.
Published: May 2009

An example of the generalization of the synthesis of 8‐azahypoxanthines A and 8‐azaadenines B, interesting from a medicinal point of view, is presented by utilizing l‐amino‐2‐hydroxy‐3‐azidopropanes.
Tricyclic heteroaromatic systems. 1,2,3,4‐tetrahydropyrazolo[4,3‐c][l]benzazepin‐1‐ones as potential antitumor agents
Authors: Palazzino Giovanna , Cecchi Lucia , Colotta Vittoria , Melani Fabrizio , Filacchioni Guido
Published: May 2009

The synthesis of 1,2,3,4‐tetrahydropyrazolo[4,3‐c][1]benzazepin‐1‐ones 1 and that of its 10‐methyl derivative 2 is reported. The preparation of the latter from 3‐(2‐aminobenzyl)3‐pyrazolin‐5‐one and triethyl ortho‐formate gave as the main product a derivative of the new tricyclic ring system, pyrazolo[1,5‐c][1,3]benzo‐diazepine. The structures of the new compounds synthesized were assigned by means of a 13C nmr study.