bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of 4‐oxo‐4H‐quino[2,3,4‐i,j][1,4]‐benoxazine‐5‐carboxylic acid derivatives
Authors: Chu Daniel T. W. , Maleczka Robert E. 
Published: April 2009

AbstractThe synthesis and antibacterial activity of 1‐substituted amino‐2‐fluoro‐4‐oxo‐4H‐quino[2,3,4‐i,j][1,4]benox‐azine‐5‐carboxylic acid derivatives is described. Key steps in the synthesis include carbon homologation and two intramolecular nucleophilic displacement cyclization reactions to generate the 4‐oxo‐4H‐quino[2,3,4‐i,j]‐[1,4]benoxazine‐5‐carboxylic acid nucleus.
MNDO and MINDO/3 study of the reactivity of 3‐pyrrolin‐2‐one tautomers and derivatives
Authors: Ribó Josep M. , Vallés Asunción 
Published: April 2009

AbstractMINDO/3 and MNDO methods have been applied to the study of the reactivity of 3‐pyrrolin‐2‐one tautomers and derivatives. The different parameters that can influence the reactivity from the frontier molecular orbital point of view (atomic charge distribution, frontier orbital energy and frontier orbital reactivity indices) are compared and evaluated with respect to the experimental reactivity already known.
Reactivity of a cyclic α‐bromoiminium bromide towards nucleophiles
Authors: Donati Donato , Fusi Stefania , Macripò Maria Adelaide , Ponticelli Fabio 
Published: April 2009

AbstractPiperidine‐pyrrolidine ring contraction of 1‐piperideinium bromide (1) was observed by reaction with aqueous bases, sodium methoxide, phenylhydrazine, (S)‐1‐phenylethylamine and sodium borohydride, whereas diazomethane addition mainly gave pyrrolo[3,4‐b]pyridine derivative 8. Some stereochemical features of these reactions have been investigated. 1 gave back bromine under suitable conditions.
Synthesis of 1α and 1β‐acylamino and alkylamino‐1,2,3,4,5,6‐hexahydro‐2,6‐methano‐3‐benzazocines and related compounds
Authors: Hirani Shabir K. , Parfitt Robert T. 
Published: April 2009

AbstractThe synthesis of series of 1α and 1β‐alkylamino‐1,2,3,4,5,6‐hexahydro‐2,6‐methano‐3‐benzazocines from the corresponding acylamino intermediates is described. Cyclization of the 1β‐chloromethylamido derivative 20 to the novel bridged benzomorphan 21 occurred whereas the corresponding 1β‐chloromethylamido derivative 19 failed to cyclize for steric reasons. In addition several related 1α‐acylamidomethyl‐ and 1β‐alkyl‐aminomethyl benzomorphans are reported.
A practical synthesis of 2,3‐dihydro‐2‐benzofurancarboxylic acid: A general route to 2,3‐dihydrobenzofurans
Authors: Edwards Colin R. , Readhead Michael J. , Tweddle Neil J. 
Published: April 2009

AbstractA practical synthesis of 2,3‐dihydro‐2‐benzofurancarboxylic acid is reported in five steps and approximately 40% overall yield. The methodology offers a useful new route to 2‐substituted‐2,3‐dihydrobenzofurans.
Condensed 1,3,5‐triazines: 1,3,4‐Thiadiazolo[3,2‐a]‐1,3,5‐triazines and isoxazolo[2,3‐a]‐1,3,5‐triazines
Authors: El‐Kerdawy Mohamed M. , Bayomi Said M. , Shehata Ihsan A. , Glennon Richard A. 
Published: April 2009

AbstractA convenient route is reported for the synthesis of substituted 1,3,4‐thiadiazolo[3,2‐a]‐1,3,5‐triazine‐5,7‐diones and isoxazolo[2,3‐a]‐1,3,5‐triazines. Condensation of the appropriately substituted 2‐amino‐1,3,4‐thiadiazole and 3‐aminoisoxazole with phenoxycarbonyl isocyanate provides the desired target compounds in fair yield.
Synthesis of heterocyclic compounds related to fredericamycin A – the cyclopent[g]isoquinoline system
Authors: Clive Derrick L. J. , Sedgeworth Janette 
Published: April 2009

AbstractA synthetic route is described to compounds 9 and 10, which resemble the cyclopent[g]isoquinoline system of the antitumor agent, Fredericamycin A. The method is based upon directed lithiation of the pyridine 6 and conjugate addition to 2‐cyclopenten‐1‐one. Cyclization of the product 7 with base then generates the required skeleton, which can be aromatized and methylated (7 → 8 → 9).
Synthesis of 4,8‐dimethoxy‐3H‐benz[f]indol‐3‐one. Anomalous behaviour to cyclization of 1,4,5‐trimethoxy‐3‐amino‐γ‐chloroalkylnaphthalene intermediates
Authors: Malesani Giorgio , Ferlin Maria Grazia 
Published: April 2009

AbstractA new linear benz[f]indole derivative 15 bearing two methoxyls in the fused naphthalene moiety was prepared as a potential chemotherapeutic agent. The anomalous behaviour of two trimethoxynaphthalene intermediates in parallel stages of the planned synthesis route is emphasized, and the corresponding mechanisms for these cyclizing reactions are proposed and discussed.
Methylation of 2‐phenylamino‐1,3,4‐thiadiazole. A structure debated
Authors: Buccheri Francesco , Cusmano Giuseppe , Noto Renato , Rainieri Rosina , Werber Giuseppe 
Published: April 2009

AbstractThe true identity of the 4‐methyl‐5‐phenylimino‐δ2‐1,3,4‐thiadiazoline (A) has been demonstrated. The reactions, previously reported in the literature to give A have been repeated and the structure of the compounds obtained has been established.
Tautomerism in alloxan
Authors: Millefiori Salvatore , Millefiori Arcangelo 
Published: April 2009

AbstractAb initio STO‐3G, 3‐21G and 6‐31G calculations have been used to investigate the energetics of the tautomerism in alloxan. The geometries of the tautomers have been fully optimized at STO‐3G level. The results indicate that tautomerism in alloxan in the vapour is highly unlikely, the trioxo structure being by far the most stable structure. The population analysis of the alloxan anion gives evidence that the preferred protonation site is offered by the central oxygen atom, and rules out the opposite oxygen atom as a possible protonation site.
A new synthesis of 2,3‐disubstituted quinoxaline 1,4‐dioxides catalyzed by molecular sieves
Authors: Takabatake Tohru , Hasegawa Minoru 
Published: April 2009

AbstractThe syntheses of 2,3‐disubstituted quinoxaline 1,4‐dioxides are smoothly and efficiently carried out by the adsorption of the components on molecular sieve 3A (powder) from benzofuroxan 1 and 1,3‐diketones, 3‐oxo‐alkanoic esters, or 3‐oxoalkanamides 2.
Cycloaddition reactions of cyclic ketene‐N,S‐acetals with 1,2,4,5‐tetrazines
Authors: Marcelis Antonius T. M. , Van Der Plas Henk C. 
Published: April 2009

AbstractReaction of 3,6‐diphenyl‐, 3,6‐bis(2‐pyridyl)‐ and the unsubstituted 1,2,4,5‐tetrazine with 4,5‐dihydro‐1‐methyl‐2‐(methylthio)pyrrole (2) and 1‐raethyl‐2‐(methylthio)‐4.5,6,7‐tetrahydroazepine (3) gives 4,7‐di‐R‐2,3‐dihydro‐1‐methylpyrrolo[2,3‐d]pyridazine (4, R = phenyl, 2‐pyridyl, hydrogen) and 6,9‐di‐R‐1‐methyl‐2,3,4,5‐tetrahydropyridazino[4,5‐6]azepine (5), R = phenyl, 2‐pyridyl, hydrogen), respectively, in reasonable to good yields. The compounds 4 (R = phenyl, hydrogen) are converted into their corresponding 1‐methylpyrrolo‐[2,3‐d]pyridazines 6 by reaction with potassium permanganate in butanone. Reaction of 3‐phenyl‐1,2,4,5‐te‐trazine with 2 and 3 leads to the exclusive formation of the 7‐phenyl isomer 4d and 9‐phenyl isomer 5d, respectively, indicating that the cycloaddition is regiospecific. The mechanism is discussed.
Pyrido[2′1′:2,3]imidazo[4,5‐c]isoquinoline and the alkylation of pyrido[2′,1′:2,3]imidazo[4,5‐c]isoquinolin‐5(6H)‐one
Authors: Paolini John P. , Palopoli Frank P. , Lendvay Louis J. , Huffman John 
Published: April 2009

AbstractThe reaction of 2‐aminopyridine, o‐phthaldehydic acid and potassium cyanide gave pyrido[2′,1′:2,3]imidazo[4,5‐c]isoquinolin‐5(6H)‐one, which upon treatment with propargylbromide, yielded both O and N alkylated products. 2‐Aminopyridine, o‐phthaldehyde and potassium cyanide gave 1‐cyano‐2‐(2‐pyridyl)isoindole which rearranged in acid to give the previously unreported parent pyrido[2′,1′:2,3]imidazo[4,5‐c]isoquinole. Structures were confirmed using uv, ir, nmr and x‐ray spectroscopy.
Heterocycles. 10. A facile synthesis of 7‐hydroxy‐6,7‐dihydro‐5H‐pyrrolo[1,2‐a]imidazole
Authors: Weintraub Philip M. , Tiernan Paul L. , Huffman John C. 
Published: April 2009

AbstractReaction of imidazole with acrolein gave the title compound whose structure was confirmed by X‐ray analysis.
Synthesis of 1′‐methylspiro[3H‐indole‐3,n'‐piperidines] from 1‐methyl‐n‐piperidinecarbaldehydes
Authors: Benito Y. , Canoira L. , Martinez‐Lopez N. , Rodriguez J. G. , Temprano F. 
Published: April 2009

Abstract1′‐Methylspiro[3H‐indole‐3,n'‐piperidines] 2 can be obtained from the 1‐methyl‐n‐piperidinecarbaldehydes 1 by the Fischer reaction of their phenylhydrazones. The Fischer reaction provides different kinds of products ‐3H‐indole, indole and oxindole‐ which depend on the N atom position in the piperidine ring.
Ozonolysis of five‐membered heterocycles
Authors: Kashima Choji , Hibi Shigeki , Maruyama Tatsuya , Harada Kazuo , Omote Yoshimori 
Published: April 2009

AbstractThe relative reaction rate of five‐membered heterocycles with ozone was evaluated. These relative rates were correlated to the highest bond order value in the corresponding ring, calculated by the convenient HMO method. From this correlation, the reactivity of heterocycles with ozone was able to be predicted. Also it was concluded that the predominant product in the ozonolysis of five‐membered heterocycles containing an oxygen atom was the corresponding carboxylic acid, while nitrogen heterocycles gave the corresponding amide.
Pyridylethyl: A versatile protecting group. Part II. The protection of heterocyclic N‐H groups
Authors: Katritzky Alan R. , Khan Ghulam R. , Marson Charles M. 
Published: April 2009

AbstractPyrrole, indole, carbazole and imidazole have been protected as N‐[2‐(4‐pyridyl)ethyl] derivatives. Deprotection occurred under mild conditions after quaternisation. 3‐Bromoindole was prepared by bromin‐ation of the protected parent indole.
Nitrogen bridgehead compounds, part 68. Studies on quinolizine derivatives. Part 2. Synthesis of 1,3‐disubstituted‐4H‐quinolizine derivatives
Authors: Schwartz Angéla , Pál Zoltán , Szabó László , Simon Kálmán , Hermecz István , Mészáros Zoltán 
Published: April 2009

AbstractQuinolizine compounds 1 and 2 or their monocyclic tautomers 3 and 4 have been synthesized using 2‐pyri‐dineacetic acid derivatives 6a, b, A, B and ethoxymethylenemalonic acid derivatives 7a, b, c in base catalyzed or thermic reaction. In the 6‐unsubstituted series, both the 4‐oxo and 4‐imino derivatives could have been obtained, in the 6‐substituted series, however the 4‐oxo ones only, whereas instead of the 4‐imino derivatives, their monocyclic tautomers 3, 4 have been isolated. In the 6‐unsubstituted series, the primarily formed 4‐imino compounds have been rearranged into 4‐oxo ones under stronger conditions. The structure of the isolated compounds have been proved by ultraviolet, infrared and 1H nmr spectra, that of 3B=C by X‐ray analysis as well.
Nitrogen bridgehead compounds. Part 70. Studies on quinolizine derivatives. Part 4. Ultraviolet‐visible spectra and chemical properties of some quinolizine derivatives and their monocyclic tautomers
Authors: Schwartz Angéla , Szabó László , Pusztay‐Szabó Katalin , Hermecz István , Mészáros Zoltán 
Published: April 2009

AbstractUltraviolet‐visible spectra of 4‐oxo 1 and 4‐imino 2 quinolizines or their monocyclic tautomers 3, 4 have been studied in neutral, acidic and basic ethanolic solution as well as in dimethyl sulfoxide and chloroform. Ring B of 4‐oxo and 6‐unsubstituted 4‐imino compounds can be cleaved by sodium ethanolate more or less easily. Ring B of 6‐methyl‐4‐iminoquinolizines is very unstable and they are present mainly in the monocyclic form which are partly dissociated in ethanol and dimethyl sulfoxide especially in higher dilution or in the presence of sodium ethanolate. In dilute acidic ethanol or chloroform, the dissociation is suppressed and in the latter solvent and in some cases, absorption bands can be observed due to a small amount of the 4‐imino‐6‐methylquinolizines. In acidic solution of compounds 3B=C, 3D, 4E, 4F=G having simultaneously cyano and ethoxycarbonyl groups in 1 and 3 position, not simple reprotonation occurs but irreversible changes can be observed.
Synthesis and dopaminergic activity of trans‐4‐methyl‐3‐phenylpyrrolidines
Authors: Tschappat Kathryn D. , Crider A. Michael , Hassan Mohamed N. , Fahn Stanley 
Published: April 2009

Abstracttran‐3‐(3,4‐Dihyroxyphenyl)‐4‐methyl‐1‐(n‐propyl)pyrrolidine 13 trans‐3‐(3‐Hydroxyphenyl)‐4‐methyl‐1(n‐propy)pyrrolidine 14 were synthesized and evaluated for dopaminergic activity. The stereochemical assignments of 13 and 14 were determined by nmr. Both 13 and 14 were either inactive or weakly active in most dopaminergic tests.
Quinazolines and 1,4‐benzodiazepines. XCVI. Compounds derived from benzodiazepine‐2‐acetic acid
Authors: Walser A. , Flynn T. 
Published: April 2009

Abstract1,4‐Benzodiazepine‐2‐acetic acid derivatives were prepared and converted to compounds with a heterocyclic ring fused to the a‐face of the benzodiazepine system. Representatives of pyrido[1,2‐a][1,4]benzodiaze‐pines, pyrimido[1,6‐a][1,4]benzodiazepines and [1,3]oxazino[3,4‐a][1,4]benzodiazepines are described. Some of the compounds showed marked CNS‐activity as measured by the antimetrazole test which is a well established primary screening method for assessment of benzodiazepine type activity.
Halogenation of [2‐(trimethylsilyl)ethoxy]methyl (SEM) protected 2,2′‐Bi‐H‐imidazole
Authors: Matthews Donald P. , Whitten Jeffrey P. , Mccarthy James R. 
Published: April 2009

Abstract2,2′‐Bi‐1H‐imidazole, when protected with the [2‐(trimethylsilyl)ethoxy]methyl (SEM) blocking group, on treatment with N‐bromosuccinimide or N‐chlorosuccinimide yields predominantly the monohalogenated derivatives 4a and 4b. The [2‐(trimethylsilyl)ethoxy]methyl group is subsequently removed to yield pure mono‐halo‐2,2′‐bi‐H‐imidazoles 2.
Synthesis of 1‐(1,1‐dimethylethyl)‐1H‐pyrazole‐4‐carboxylate ester derivatives
Authors: Beck James R. , Lynch Michael P. 
Published: April 2009

AbstractAttempts to prepare ethyl 5‐cyano‐1‐(1,1‐dimethylethyl)‐1H‐pyrazole‐4‐carboxylate (7) by the reaction of the corresponding 5‐chloro derivative 1b with cyanide ion were unsuccessful. The chloro ester was synthesized from the corresponding amino ester la utilizing nonaqueous diazotization with nitrosyl chloride. An alternate process was developed which allowed the preparation of 7 from the corresponding 5‐methyl ester 3 in four steps. The structure of the N‐methylamide 8 synthesized from 7 was confirmed by X‐ray diffraction analysis.
Aroylnitrile oxide cyclizations. 2. Synthesis of (3‐aroylisoxazol‐5‐yl)alkanoic acids
Authors: Tegeler John J. , Diamond Craig J. 
Published: April 2009

AbstractIntermolecular cyclization of 1,3‐dipolar aroylnitrile oxides to terminal alkynols followed by phase transfer catalyzed oxidation provided a short, convenient route to several novel (3‐aroylisoxazol‐5‐yl)alkanoic acids.
Synthesis of 1‐aryl‐5‐(trifluoromethyl)‐1H‐pyrazole‐4‐carboxylic acids and esters
Authors: Beck James R. , Wright Fred L. 
Published: April 2009

AbstractEthyl 1‐aryl‐5‐(trifluoromethyl)‐1H‐pyrazole‐4‐carboxylates 2 were prepared by the condensation of arylhydrazines with ethyl 3‐ethoxy‐2‐(trifluoroacetyl)‐2‐propenoate (1a) at low temperature. The corresponding acids were also synthesized. X‐ray diffraction analysis of an amide derivative 4 verified the position of the trifluoromethyl group on the pyrazole ring.
Reaction of 4‐acylaminomethylpyridine N‐oxides with phenylbutazone in the presence of acetic anhydride
Authors: Braña M. F. , Castellano J. M. , Redondo M. C. , Esplugues J. 
Published: April 2009

AbstractReaction of 4‐acylaminomethylpyridine N‐oxides with phenylbutazone in the presence of acetic anhydride is described. In the pharmacological screening one compound shows an interesting anticonvulsant activity.
Synthesis of 1,2‐benzoquinones by the oxidation of 1,4‐benzodioxins by peroxide derivatives
Authors: Kashima Choji , Tomotake Atsushi , Omote Yoshimori 
Published: April 2009

AbstractThe oxidation reaction of 1,4‐benzodioxin 1 by m‐chloroperbenzoic acid (m‐CPBA) and t‐butyl hydroperoxide (t‐BHP) are reported. 1,2‐Benzoquinone 2 was given in moderate yields by the m‐CPBA oxidation of 1,4‐benzodioxin 1, while 1,2‐benzoquinone 2 was predominantly formed by t‐BHP oxidation.
Synthesis of hexahydro‐5H‐benz[g]imidazo[2,1‐a]‐ isoindole 2via an intramolecular diels‐alder reaction and a novel lawesson's reagent mediated cyclization
Authors: Basha Fatima Z. , Debernardis John F. 
Published: April 2009

AbstractThe 2‐(5,6‐dihydroxy‐1,2,3,4‐tetrahydro‐1‐naphthyl)imidazoline 1 is a recently reported potent alpha‐adrenergic agent [1]. In continuation of our work on the synthesis of potential adrenergic agents we required imidazoisoindole 2 in order to investigate the biological effects of incorporation of additional rigidity into the parent system. This paper describes the synthesis of 2 via an intramolecular Diels‐Alder reaction and a novel Lawesson's reagent mediated cyclization.
Un equivalent synthetique de la triformyl s‐triazine
Authors: Sumera F. , Le Rouzic A. , Raphalen D. , Kerfanto M. 
Published: April 2009

AbstractLa tris‐dimorpholinométhyl s‐triazine 2 se comporte comme un équivalent synthétique de la triformyl s‐triazine 1. Ainsi à partir du composé 2 nous préparons des dérivés caractéristiques 5 du trialdéhyde 1: des triphénylhydrazones, la trialdoxime, la trisemicarbazone et la tris [bis (N,N‐diméthylamino‐4 phényl) méthyl] s‐triazine.
Addition of dihalocarbenes to 3H‐1,5‐benzodiazepines. Synthesis of 2H‐bisazirino[1,2‐a:2′,1′‐d][1,5]benzodiazepines
Authors: Takahashi Masahiko , Takada Tsugumasa , Sakagami Takeshi 
Published: April 2009

AbstractAddition of dihalocarbenes, generated from haloforms using a phase transfer catalyst, to 3H‐1,5‐benzodi‐azepines gave 2H‐Bisazirino[1,2‐a:2′,1′‐d][1,5]benzodiazepines, a new ring system.
Correlation of ring nitrogen substituents with carbon‐13 nuclear magnetic resonance data in azoloazines
Authors: Pugmire Ronald J. , Smith James C. , Grant David M. , Stanovnik Branko , Tišler Miha , Verček Bojan 
Published: April 2009

AbstractCarbon–13 nuclear magnetic resonance data have been acquired on 22 azoloazines. Chemical shifts have been correlated by a step–wise linear multiple regression with nitrogen substituents in both the 5‐ and 6‐membered rings using pyrrolo[1,2‐α]pyridine as the reference for chemical shift correlation. The data demonstrate that a highly correlated set of chemical shift parameters exist. Nitrogen substitution in the five–membered ring produces larger cross–ring effects than are oberved in the five–membered ring when substitution occurs in the six–membered ring. Within the six–membered ring a constant para‐ substituent parameter is noted. The meta‐ and para‐ parameters are more complex and fall into two groups for each parameter. Within the five–membered ring, a highly regular chemical shift pattern is observed which reflects an attenuated perturbation from nitrogen substitution in the six–membered ring.
Synthesis of novel 1‐phenyl‐1H‐indole‐2‐carboxylic Acids. I. Utilization of ullmann and dieckmann reactions for the preparation of 3‐hydroxy, 3‐alkoxy, and 3‐alkyl derivatives
Authors: Unangst Paul C. , Connor David T. , Stabler S. Russell , Weikert Robert J. 
Published: April 2009

AbstractMethods for the synthesis of novel 3‐hydroxy, 3‐alkoxy, and 3‐alkyl indole‐2‐carboxylic acids and esters are described. Dieckmann cyclization of various 2‐[(carboxymethyl)amino]benzoic acid diesters yielded 1‐unsubstituted‐, 1‐methyl‐, and 1‐phenyl‐3‐hydroxy‐1H‐indole‐2‐carboxylic acid esters. An Ullmann reaction with bromobenzene converted 1H‐indoles to 1‐phenylindoles.
Synthesis of novel 1‐phenyl‐1H‐indole‐2‐carboxylic acids. II. Preparation of 3‐dialkylamino, 3‐alkylthio, 3‐alkylsulfinyl, and 3‐alkylsulfonyl derivatives
Authors: Unangst Paul C. , Connor David T. , Stabler S. Russell 
Published: April 2009

AbstractThe synthesis of novel indole‐2‐carboxylic acids with amino‐ and sulfur‐containing substituents in the indole 3‐position is described. An Ullmann reaction with bromobenzene converted 1H‐indoles with 3‐(acetylamino)‐ and 3‐(diethylamino)‐substituents into 1‐phenyl‐1H‐indoles. Reaction of 3‐unsubstituted indoles with thionyl chloride provided indole 3‐sulfinyl chlorides, which reacted with alkyl and aryl Grignard reagents to form the corresponding sulfoxides. The indole sulfoxides thus obtained were reduced to sulfides or oxidized to sulfones.
9‐deazapurine nucleosides. The synthesis of certain N‐5‐2′‐deoxy‐β‐D‐erythropentofuranosyl and N‐5‐β‐D‐arabinofuranosylpyrrolo[3,2‐d]pyrimidines
Authors: Girgis Nabih S. , Cottam Howard B. , Larson Steven B. , Robins Roland K. 
Published: April 2009

AbstractA number of 2,4‐disubstituted pyrrolo[3,2‐d]pyrimidine N‐5 nucleosides were prepared by the direct glycosylation of the sodium salt of 2,4‐dichloro‐5H‐pyrrolo[3,2‐d]pyrimidine (3) using 1‐chloro‐2‐deoxy‐3,5‐di‐O‐(p‐toluoyl)‐α‐D ‐erythropentofuranose (1) and 1‐chloro‐2,3,5‐tri‐O‐benzyl‐α‐D‐arabinofuranose (11). The resulting N‐5 glycosides, 2,4‐dichloro‐5‐(2‐deoxy‐3,5‐di‐O‐(p‐toluoyl) ‐β‐D‐erythropentofuranosyl)‐5H‐pyrrolo‐[3,2‐d]pyrimidine (4) and 2,4‐dichloro‐5‐(2,3,5‐tri‐O‐benzyl‐β‐D‐arabinofuranosyl‐5H ‐pyrrolo [3,2‐d)pyrimidine (12), served as versatile key intermediates from which the N‐7 glycosyl analogs of the naturally occurring purine nucleosides adenosine, inosine and guanosine were synthesized. Thus, treatment of 4 with methanolic ammonia followed by dehalogenation provided the adenosine analog, 4‐amino‐5‐(2‐deoxyerythropentofuranosyl) ‐5H‐pyrrolo[3,2‐d]pyrimidine (6). Reaction of 4 with sodium hydroxide followed by dehalogenation afforded the inosine analog, 5‐(2‐deoxy‐β‐D‐erythropentofuranosyl) ‐5H‐pyrrolo[3,2‐d]pyrimidin‐4(3H)‐one (9). Treatment of 4 with sodium hydroxide followed by methanolic ammonia gave the guanosine analog, 2‐amino‐5‐(2‐deoxy‐β‐D‐erythropentofuranosyl) ‐5H‐pyrrolo[3,2‐d]pyrimidin‐4(3H)‐one (10). The preparation of the same analogs in the β‐D‐arabinonucleoside series was achieved by the same general procedures as those employed for the corresponding 2′‐deoxy‐β‐D‐ribonucleoside analogs except that, in all but one case, debenzylation of the sugar protecting groups was accomplished with cyclohexene‐palladium hydroxide on carbon, providing 4‐amino‐5‐β‐D‐arabinofuranosyl‐5H‐pyrrolo [3,2‐d]pyrimidin‐4(3H)‐one (18). Structural characterization of the 2′‐deoxyribonucleoside analogs was based on uv and proton nmr while that of the arabinonucleosides was confirmed by single‐crystal X‐ray analysis of 15a. The stereospecific attachment of the 2‐deoxy‐β‐D‐ribofuranosyl and β‐D‐arabinofuranosyl moieties appears to be due to a Walden inversion at the C1 carbon by the anionic heterocyclic nitrogen (SN2 mechanism).
Synthesis of 3‐phenylpyrroles by hydride reduction of 4‐hydroxypyrrolidin‐2‐ones
Authors: Hasegawa Tadashi , Nakamura Fuki , Moribe Jun‐Ichi , Yoshioka Michikazu 
Published: April 2009

Abstract3‐Phenylpyrroles 2 were easily prepared in good yields by hydride reduction of 4‐hydroxypyrrolidin‐2‐ones 1, which have been prepared in high yields from the photoreaction of N,N‐dialkylbenzoylacetamides, with lithium aluminum hydride.
A simple regioselective synthesis of pyrimido[1,2‐a]benzimidazoles
Authors: Tseng Shin‐Shyong , Epstein Joseph W. , Brabander Herbert J. , Francisco Gerardo 
Published: April 2009

Abstract2‐Aminobenzimidazoles were reacted with enaminones in acetic acid to give pyrimido[1,2‐a]benzimidazoles. With a substituted enaminone only one regioisomer was obtained. Structural assignments based on nmr and uv spectroscopy are presented. Possible pathways leading to the products are discussed.