bluuebunny/crossref_metadata_2025_split huggingface dataset:
A regioselective route to 3‐alkyl‐1‐aryl‐1H‐pyrazole‐5‐carboxylates: Synthetic studies and structural assignments
Authors: Ashton Wallace T. , Doss George A. 
Published: March 2009

AbstractEthyl 2,4‐dioxooctanoate (1) was selectively protected as the 2‐(methoxyimino) derivative 2. When 2 was reacted with phenylhydrazine hydrochloride, ethyl 3‐butyl‐1‐phenyl‐1H‐pyrazole‐5‐carboxylate (4) was favored over the corresponding 5‐butyl‐1‐phenyl‐1H‐pyrazole‐3‐carboxylate product 5 by a ratio of at least 6:1, a complete reversal of the regioselectivity observed for 1. The structures of 4 and 5 were assigned definitively by NOE difference experiments. Regiochemical and configurational assignments of the mono‐ and bis(methoxyimino) derivatives of 1 were also achieved by ID and 2D 1H and 13C nmr methods.
Retro‐ene reaction I: Reaction of N‐hydroxymethylsaccharin with benzoyl chlorides and alkyl halides
Authors: Kim Sung‐Kyu , Moon Jung‐Gyen , Lee Sang‐Gyeong , Choi Sam‐Young , Cho Su‐Dong , Choi Woo‐Yong , Yoon Yong‐Jin 
Published: March 2009

AbstractN‐Benzoylsaccharins, N‐(saccharinylmethyl) benzoates and N‐alkylsaccharins were synthesized from N‐hydroxymethylsaccharin and the corresponding benzoyl chlorides or alkyl halides under different conditions. The reaction mechanisms are also discussed.
Site‐selective photocycloadditions of 2‐pyrones with electron‐poor olefins and the derivation from the cycloadducts
Authors: Shimo Tetsuro , Yamasaki Shinichi , Date Kenichi , Uemura Hisako , Somekawa Kenichi 
Published: March 2009

AbstractPhotosensitized cycloaddition of 4,6‐dimethyl‐2‐pyrone (1) with methacrylonitrile (3b) afforded two types of [2 + 2]cycloadducts, 4b and 6b, across the C5‐C6 and C3‐C4 double bonds in 1, respectively. Photosensitized reactions of 1 with dimethyl maleate and dimethyl cyclobutene‐1,2‐dicarboxylate gave [2 + 2]cycload‐ducts 4d, 4e across the C5‐C6 double bond, in addition to [4 + 2]cycloadduct 9d or bicyclo[4.2.0]octadiene 10e. The photoreactions of methyl 2‐pyrone‐5‐carboxylate (2) with 3b and 2‐chloroacrylonitrile (3c) gave [4 + 2]cycloadducts 5b, 5c in addition to [2 + 2]cycloadducts 11b and 11c across the C5‐C6 double bond in 2. The photocycloaddition mechanism was explained from results calculated by means of PM3‐CI method. Namely, the site‐ and/or regio‐selective products, 4, 5, 8, 9 and 10 were thought to come from the same site‐selective radical intermediates in the case of electron‐poor olefins. Pyrolysis and/or hydrolysis of the cycload‐ducts 4e, 5b, 5c gave 5,6‐dihydro‐2‐pyrone 12 or benzene derivatives.
Reaction of 3‐benzylidene‐2,4‐pentanedione and 3‐methoxymethylene‐2,4‐pentanedione with aroylhydrazines
Authors: Mitkidou Sophia , Stephanidou‐Stephanatou Julia , Stephopoulou Helen 
Published: March 2009

AbstractAroylhydrazines 2 reacted with 3‐benzylidene‐2,4‐pentanedione (1) to give 1‐aroyl‐3,5‐dimethyl‐1H‐pyrazoles 5 and benzaldehyde aroylhydrazones 6. From the reaction of 3‐methoxymethylene‐2,4‐pentanedione (7) with aroylhydrazines 2 the unknown N‐aroyl‐4‐acetyl‐1H‐pyrazoles 9 were exclusively isolated in good yields.
Porphyrins with exocyclic rings. Part 4. An improved one step synthesis of cyclopenta[b]pyrroles
Authors: Quizon‐Colquitt Desiree M. , Lash Timothy D. 
Published: March 2009

AbstractCyclopentanone condensed with phenylhydrazones 5, or oximes 6, in the presence of zinc dust, sodium propionate and propionic acid at 150° to give cyclopenta[b]pyrroles 7 in good yields. This chemistry was extended to the synthesis of pyrrolic products from 1‐indanone, 2‐indanone and 2‐methylcyclopentanone. Benzyl 3‐methylcyclopenta[b]pyrrole‐2‐carboxylate was found to react regioselectively with lead tetraacetate to give the corresponding 6‐acetoxy derivative and subsequent acid‐catalyzed condensations with 5‐unsubsti‐tuted pyrrole‐2‐carboxylates afforded a series of synthetically valuable dipyrroles 18a‐c.
Reactions of amidoximes with orthoacetates
Authors: Kaugars Girts , Watt William 
Published: March 2009

AbstractThe reaction of two amidoximes 4 with ethyl orthoacetate in the presence of an acid catalyst gave triazine N‐oxides 7. A mechanism via a Beckmann rearrangement to a carbodiimide, followed by reaction with amidoxime and the ortho ester, is proposed.
4‐benzoyl‐5‐phenyl‐1,3‐oxathiol‐2‐one. Synthesis and reaction with N‐nucleophiles
Authors: He‐Xi Chang , Kollenz Gert 
Published: March 2009

AbstractThe synthesis of 4‐benzoyl‐5‐phenyl‐1,3‐oxathiol‐2‐ones 1 and the behaviour of 1a against several amines were investigated to afford aminomercaptoethenes 2 or thiocarbamates 3, as well as complete cleavage to sulfur, dibenzoylmethane and the corresponding urea, depending on the nature of the N‐nucleophile used.
The chloromethylation of codeine. Isolation of a quaternary iodide
Authors: Grant Andrew D. , Zacharias David E. , Mascavage Linda M. , Kemmerer George E. , Dalton David R. 
Published: March 2009

AbstractA single N‐chloromethylcodinium iodide has been isolated from the reaction of chloroiodomethane with codeine. Complete proton and carbon nmr and X‐ray analyses dictate that this stable material bears the chloromethyl group axial. It is identical (except for the anion) to one of the salts obtained on long term storage of codeine in dichloromethane.
A new method for the synthesis of 6H,11H‐indolo[3,2‐c]‐isoquinolin‐5‐ones/thiones and their reactions
Authors: Hiremath Shivayogi P. , Saundane Ananda R. , Mruthyunjayaswamy B. H. M. 
Published: March 2009

AbstractThe synthesis of 8‐substituted and unsubstituted 6H,11H‐indolo[3,2‐c]isoquinolin‐5‐ones/thiones 3a‐c and 4a‐c and their derivatives viz, ethyl (8‐substituted‐6H,11H‐indolo[3,2‐c]isoquinolin‐5‐on‐6‐yl)acetates 5a‐c, (8‐substituted‐6H,11H‐indolo[3,2‐c]isoquinolin‐5‐on‐6‐yl)acetyl hydrazides 6a‐c, 3,5‐disubstituted‐pyrazoles 7a‐c and 8a‐c, 3‐substituted‐pyrazol‐5‐ones 9a‐c and 5‐(8‐substituted‐6H,11H‐indolo[3,2‐c]isoquinolin‐5‐on‐6‐yl)methyl‐1,3,4‐oxadiazole‐2‐thiones 10a‐c, also ethyl (8‐substituted‐11H‐indolo[3,2‐c]isoquinolin‐5‐ylthio)ace‐tates 11a‐c, (8‐substituted‐11Hindolo[3,2‐c]isoquinolin‐5‐ylthio)acetyl hydrazides 12a‐c, 3,5‐disubstituted‐pyrazoles 13a‐c and 14a‐c, 3‐substituted‐pyrazol‐5‐ones 15a‐c and 5‐(8‐substituted‐11H‐indolo[3,2‐c]isoquin‐olin‐5‐yl)thiomethyl‐1,3,4‐oxadiazole‐2‐thiones 16a‐c is described.
Unusual reaction of 1,8‐diazabicyelo‐[5.4.0]undec‐7‐ene with diethyl maleate
Authors: Perbost Michel , Lucas Marc , Chavis Claude , Imbach Jean‐Louis 
Published: March 2009

AbstractMichael addition of DBU on diethyl maleate and subsequent cyclization of the adduct afforded a tricyclic derivative which was susceptible to react further with a second molecule of unsaturated diester.
Synthesis of novel 2‐substituted‐5‐oxycoumarans via A direct route to 2,3‐dihydro‐5‐hydroxy‐2‐benzofuranacetic acids
Authors: Ceccarelli Stefano , De Vellis Patrizia , Scuri Romolo , Zanarella Sergio , Brufani Mario 
Published: March 2009

AbstractA number of novel 2‐substituted 2,3‐dihydro‐5‐benzofuranols optionally protected on 5‐OH group have been prepared via a simple two step route to racemic 2,3‐dihydro‐5‐hydroxy‐2‐benzofuranacetic acids from hydroquinones and 4‐bromocrotonates.
Research on nitrogen containing heterocyclic compounds. XX. Synthesis of 8H‐Imidazo[5,1‐c]pyrrolo[1,2‐a][1,4]benzodiazepine and its 6‐derivatives
Authors: Massa Silvio , Di Santo Roberto , Costi Roberta , Artico Marino 
Published: March 2009

AbstractStarting from 1H‐1‐(2‐aminomethylphenyl)pyrrole the synthesis of 8H‐imidazo[5,1‐c]pyrrolo[1,2‐a][1,4]ben‐zodiazepine, a novel nitrogen containing tetracyclic ring, has been performed by two routes involving a three‐step and a six‐step sequence, respectively. The more complex sequence offers the advantage to obtain also 3‐alkyl and 3‐aryl derivatives of the parent nucleus. The three step sequence involves the use of toluene‐4‐sulfonylmethylisocyanide (TosMIC) as a synthon.
The synthesis of electron donor‐acceptor substituted pyrazoles
Authors: Miller R. D. , Reiser O. 
Published: March 2009

AbstractA variety of 1,3‐ and 1,5‐donor‐acceptor substituted pyrazole derivatives have been synthesized by the cyclocondensation of α,β‐ethynyl ketones with substituted phenyl hydrazines. The regioselectivity of the cyclization depends on the reaction conditions in a manner consistent with competitive 1,2‐ and 1,4‐addition followed by ring closure. 1,4‐Disubstituted derivatives can be prepared from the corresponding 4‐iodopyrazole using palladium catalyzed carbon‐carbon bond forming reactions. The pyrazole chromophores are expected to show interesting nonlinear optical properties.
Novel synthesis modes and properties of [1,4]benzodioxinopyridazines
Authors: Chupp John P. , Jones Claude R. , Dahl Maria L. 
Published: March 2009

AbstractA simple synthesis involving fusion of catechol and derivatives with 3,4,5‐trichloropyridazine has furnished 4‐chloro[1,4]benzodioxino[2,3‐c]pyridazines 5 for the first time. This new method complements the previously reported base promoted procedure for preparing 4‐chloro[1,4]benzodioxino‐[2,3‐d]pyridazines 3. Employing both methods, 4‐(trifluoromethyl)catechol was converted to the four regio isomers 3b,c and 5c,d. Structure assignment of these four was aided by the remarkably consistent influence of the pyridazine 4‐chlorine substituent and diazo‐linkage in inducing 1H nmr downfield shifts of their nearest neighbor phenyl ring protons. Finally, contrary to what might be expected from previously reported results, reaction of methoxide with either 3 or 5, gave chlorine substitution with formation of methoxybenzodioxinopyridazines 6 and 7 respectively. However, these reactions both give what appears to be an unprecedented rearrangement, with conversion of [2,3‐c]‐pyridazine to [2,3‐d]pyridazine, and vice versa.
Synthesis and selective reactions of v‐triazolo‐[1,5‐b]pyridazinium salts with nucleophiles. A facile access to functionalized ethenyl‐1,2,3‐triazoles
Authors: Riedl Zsuzsanna , Hajós György , Messmer András , Kollenz Gert 
Published: March 2009

Abstractv‐Triazolo[1,5‐b]pyridazinium salts 5a‐c synthesized from α‐pyridazinyl ketone arylhydrazones and 2,4,4,6‐tetrabromocyclohexa‐2,5‐dien‐1‐one (TBB) reacted selectively with nucleophiles to yield ‐ besides substituted derivatives 6 ‐ ring‐opened cyano compound 9 and/or v‐triazoles containing olefinic side chain 10–12. Mechanistic considerations reveal that cation 5 reacts with nucleophiles predominantly at C‐7 unless other positions are especially activated. This selectivity proved to be in good agreement with results of semiempirical quantum chemical calculations.
Synthesis of naproxen via regioselective ring opening of (2S,3S)‐epoxy‐1‐butanol
Authors: Ahn Kyo Han , Jin Chang Soo , Ho Kang Dong , Shin Yong Soon , Kim Jeong Sook , Han Do Soon , Kim Dong H. 
Published: March 2009

Abstract(S)‐Naproxen was synthesized by the regioselective and stereospecific epoxide ring opening of (2S,3S)‐epoxy‐1‐butanol (2) with diethyl‐2‐(6‐methoxynaphthyl)aluminium (5) as the key step. Thus, treatment of di‐ethylaluminate of 2 with 5 at 0° afforded (2S,3S)‐3‐(6‐methoxy‐2‐naphthyl)butan‐1,2‐diol (6), which was oxidized by sequential treatment with sodium periodate and potassium permanganate in a mixture of tert‐butyl‐alcohol and phosphate buffer (pH 7.0) to give naproxen in high enantiomeric purity.
Formation and catalytic hydrogenation of the dimer of 1,2,3,4,5,7a‐hexahydroimidazo[1,2‐a]pyrazine
Authors: Mirkin Chad A. , Premecz Joan E. , Ford Michael E. , Johnson Thomas A. 
Published: March 2009

AbstractReaction of diethylenetriamine with glyoxal or N,N'‐dicyclohexylethylenediimine forms the novel heterocycle 1,2,3,4,5,7a‐hexahydroimidazo[1,2‐a]pyrazine 1 (R1 = R2 = H) which is isolated as its dimer. Catalytic hydrogenation converts 1 into N(2‐aminoethyl)piperazine in high yield.
Introduction of a triflate group into sterically‐hindered positions in 1‐aryl‐4,6‐diamino‐1,3,5‐triazines and their dimroth rearrangement products
Authors: Stevens M. F. G. , Chui Wai Keung , Castro M. A. 
Published: March 2009

AbstractDecomposition of 1‐(azidophenyl)‐4,6‐diamino‐1,3,5‐triazines 11–13 and their 4‐amino‐6‐(azidoanilino)‐1,3,5‐triazine isomers 31–33 in trifluoromethanesulphonic acid at 0° led to the introduction of the triflate group (OSO2CF3) into the aryl group. This method can be employed to introduce a bulky substituent into the hindered position ortho to the triazinyl substituent. Dimroth rearrangement of 1‐(aryl)‐4,6‐diamino‐1,3,5‐triazines is best effected in refluxing ethanolic pyridine.
Acetylene chemistry. Part 25. Reactions of ethyl 4‐hydroxy‐3‐quinolin‐2(1H)‐onecarboxylates with 3‐bromoprop‐1‐yne
Authors: Reisch Johannes , Iding Marlies , Schönweiler (The Late) Dörte 
Published: March 2009

AbstractEthyl 4‐hydroxyquinolin‐2(1H)‐onecarboxylates 1a and 1b which are obtained conveniently by the condensation of isatoic anhydride and diethylmalonate [4], were reacted with 3‐bromoprop‐1‐yne (2) to obtain monoand dialkylated derivatives.
The lead tetraacetate oxidation of bisacylhydrazones of α‐diketones: A scope re‐assesment
Authors: Maroulis A. J. , Akrivos P. D. , Hadjiantoniou‐Maroulis C. P. 
Published: March 2009

AbstractOxidation of the title compounds yields, besides the reported isoimides 3 and/or the amides 4, also the imides 5. The observed product dichotomy is considered as the result of an intramolecular nucleophilic attack on the aroyl group, of the pressumed zwitterionic intermediate 2, by O or N present in the ambident N‐aroylimine site of 2. The results of AM1 calculations agree with the product studies and both permit the formulation of a set of rules correlating structure and selectivity.
Polycyclic N‐heterocyclic compounds. XLIV. Synthesis of the novel B,D‐Dihomo‐11,13,15‐triazasteroidal skeleton and their effect on reserpine‐induced hypothermia and inhibitory activity on platelet aggregation
Authors: Sasaki Kenji , Arimoto Yuichi , Ohtomo Hiromi , Nakayama Taiji , Hirota Takashi 
Published: March 2009

AbstractSynthesis of benzo[3,4]cyclohepta[1,2‐e]pyrimido[1,2‐c]pyrimidines, corresponding to the B,D‐dihomo‐11,13,15‐triazasteroidal skeleton as a novel ring system is described. Their effects on reserpine‐induced hypothermia in mice and inhibitory activity against collagen‐induced platelet aggregation were also investigated.
On triazoles XXXI. The reaction of 1,2,4‐triazolylcarbothiohydrazides with homo‐ and heterocyclic ketones. An unexpected reaction leading to 4,5‐polyalkylene thiazoles
Authors: Barkóczy József , Szabó éva , Reiter József 
Published: March 2009

AbstractThe reaction of 1,2,4‐triazolylcarbothiohydrazides with homo‐ and heterocyclic ketones to yield 8‐spiro‐[1,2,4]triazolo[1,5‐d][1,2,4,6]tetrazepine‐5‐thiones 7 (n = 4, 5, 6, 7 and 11), 8 and 9, respectively, all representing novel ring systems was studied. Providing the reaction at higher temperature a novel reaction was observed to yield 4,5‐polyalkylene thiazoles for which a mechanism is proposed.
Furopyridines. XIV. Synthesis of 2‐aminoalkyl derivatives of furo[2,3‐b]‐, furo[3,2‐b], furo[2,3‐c]‐ and furo[3,2‐c]pyridine
Authors: Shiotani Shunsaku 
Published: March 2009

AbstractThe preparation of 2‐aminomethyl‐ 3a‐d, 2‐acetamidomethyl‐ 4a‐d, 2‐N,N‐dimethylaminomethyl‐ 5a‐d, 2‐(1‐hydroxy‐2‐nitroethyl)‐ 6a‐d, 2‐(1‐hydroxyl‐2‐aminoethyl)‐ 7a‐d and 2‐(1‐hydroxy‐2‐N,N‐dimethylaminoethyl)‐8b‐d derivatives of furo[2,3‐b]‐, furo[3,2‐b]‐, furo[2,3‐c]‐ and furo[3,2‐c]pyridine is described.
Synthesis and transformations of 1‐(1,3‐butadien‐1‐yl)benzotriazoles
Authors: Katritzky Alan R. , Gupta Vandana , Gordeev Mikhail 
Published: March 2009

Abstract1‐[α‐(Phenylthio)alkyl]benzotriazoles were converted into the corresponding 1‐(1,3‐butadien‐1‐yl)benzotriazoles in good yields by one‐pot sequential reactions with (i) lithium diisopropylamide, (ii) allyl bromide or cinnamyl chloride, and (iii) potassium t‐butoxide. Diels‐Alder and hetero [4 + 2] cycloadditions of 1‐(1,3‐butadien‐1‐yl)benzotriazoles and some transformations of their α‐lithio derivatives were studied.
Ring closure of 1‐[4‐(imidazol‐1‐yl)phenyl]‐3‐phenyl‐2‐propen‐1‐one derivatives to potential biologically active compounds
Authors: Coudert P. , Couquelet J. , Tronche P. , Leal F. 
Published: March 2009

Abstract1‐[4‐(Imidazol‐1‐yl)phenyl]‐3‐phenyl‐2‐propen‐1‐one 1 reacted with acetone cyanohydrin, ethyl phenylacetate and cyanoacetamide to give the adducts 2, 8 and 10 respectively. Action of hydrazine hydrate on both the γ‐ketonitrile 2 and the corresponding γ‐ketoacid 4 led to pyridazine derivatives 3 and 5. 4,5‐Dihydropyridazinone 5 was dehydrogenated by the action of bromine in acetic acid to give pyridazinone 6. Cyclization of acid 8 in acetic medium resulted in α‐pyrone 9. Cyanopentanamide 10 was converted with hydrochloric acid into δ‐ketoacid 13 which led to α‐pyrone 14 via an intramolecular dehydration. Refluxing 10 in the presence of acetic acid and ammonium acetate gave 3,4‐dihydropyridone 11 which was dehydrogenated to produce pyridone 12.
N‐Alkylation of pyrazolones with OH‐protection
Authors: Hichour M. , Mary F. , Marzin C. , Naji M. , Tarrago G. 
Published: March 2009

AbstractThe synthesis of a biheterocyclic compound containing two pyrazolone sub‐units, precursor of a new macrocyclic family, is described. It is shown that it is necessary to protect first the pyrazol‐5‐one oxygen site before condensing it with a bifunctional compound in order to obtain a selective alkylation on the heterocyclic nitrogen atom.
1,2,3‐triazol‐1‐imines. 2. Electric dipole moments and semiempirical studies of some 2‐aryl‐N‐benzoyl‐4,5‐dimethyl‐1,2,3‐triazol‐1‐imines
Authors: Hadjiantoniou‐Maroulis C. P. , Akrivos P. D. , Maroulis A. J. 
Published: March 2009

AbstractElectric dipole moments of some 2‐aryl‐N‐benzoyl‐4,5‐dimethyl‐1,2,3‐triazol‐1‐imines were measured in carbon tetrachloride solution and the results compared with those derived computationally using MNDO, AM1 and PM3. Good correlation of the dipole moments with σ+ substituent constants was obtained.
Preparation of 3(5)‐phenyl‐1‐hydroxypyrazole 2‐oxide and 4‐methyl‐3(5)‐phenyl‐1‐hydroxypyrazole 2‐oxide
Authors: Hansen John F. , Luther Matthew L. 
Published: March 2009

AbstractNitrosation of acrylophenone oxime or of methacrylophenone oxime with n‐butyl nitrite in the presence of pyridine and copper(II) sulfate gives the copper complexes of the title compounds. The free 1‐hydroxypyrazole 2‐oxides are isolated by treating the copper complexes with dilute sodium hydroxide, filtration, and acidification of the basic filtrates. The title compounds are the first examples of 1‐hydroxypyrazole 2‐oxides in which the C3(5) ring position is unsubstituted.
Synthesis of thieno[3,4‐c] and thieno[3,2‐c][2,1]benzothiazepines
Authors: Vega Salvador , Diaz Juan A. 
Published: March 2009

AbstractStarting from [4,3‐c] and [3,2‐c] methyl chlorosulfonylthiophenecarboxylates the synthesis of ketones 7 and 8 is described. These compounds are the first two representatives of the new thieno[3,4‐c] and thieno‐[3,2‐c][2,1]benzothiazepine ring systems. The formation of methyl 3‐chlorosulfonylthiophene‐2‐carboxy‐late is also revised.
Tetrazole compounds. 8. Synthesis of tetrazolylpyrimidines from tetrazolyl‐substituted enamino ketones
Authors: Fischer Gerhard W. 
Published: March 2009

AbstractTetrazolyl‐substituted enamino ketones 1 react with various amidines 2 to give 5‐(1‐phenyl‐1H‐tetrazol‐5‐yl)pyrimidines 3. In the case of the chloroacetyl enamine 4 4‐(N,N‐dimethylaminomethyl)‐substituted tetra‐zolylpyrimidines 5 were obtained. Subsequent hydrolysis of the 4‐trifluoromethyl derivatives 3b, 3d and 3g afforded the corresponding 5‐(1‐phenyl‐1H‐tetrazol‐5‐yl)pyrimidine‐4‐carboxylic acids 6.
A mass spectrometric investigation on some 4,7‐dioxo‐4,5,6,7‐tetrahydroindole derivatives
Authors: Bertazzo A. , Ferlin M. G. , Chiarelotto G. , Catinella S. , Traldi P. 
Published: March 2009

AbstractThe mass spectrometric behaviour of a series of 2‐aryl substituted 4,7‐dioxo‐4,5,6,7‐tetrahydroindoles has been studied in different ionization conditions (Electron Ionization and Fast Atom Bombardment), with the aid of the metastable ion studies. In electron ionization conditions all the compounds exhibit a highly favoured, primary H2 loss giving rise to the corresponding indole‐4,7‐diones; in the usual spectra no evidence for the molecular ions in the enolic form was found, while the OH* loss observed in the MIKE (mass analyzed ion kinetic energy) spectra of molecular ions suggests that species at low internal energy content isomerize to the corresponding tautomeric enolic form. FAB mass spectra show easy formation of an unusual [M + 2H]+ species, together with abundant [M + H]+ and M+ cations.
Synthesis and stereochemistry of new trihydrodiazabicyclo‐[3.m.n]alkano[4′,5′:1,2]pyrido[3,4‐b]indole ring system
Authors: Misztal Stanislaw , Paluchowska Maria H. , Mokrosz Maria J. , Bartyzel Piotr , Mokrosz Jerzy L. 
Published: March 2009

AbstractThe classical Pictet‐Spengler reaction of tryptamine with the isomeric N‐benzylpiperidones 3a, 3b and N‐benzylpyrrolidone 3c yielded the spiro derivatives of 1,2,3,4‐tetrahydro‐β‐carboline 5a, 5b and 5c. Cyclocon‐densation of the spirotetrahydrocarboline with chloroacetic chloride and the subsequent reductive debenzylation afforded the new ring systems of trihydrodiazabicyclo[3.m.n]alkano[4′,5′:1,2]pyrido[3,4‐b]indoles 8a, 8b, and 8c. The structures of the bicyclic systems 8a, 8b, and 8c were determined by using both, high‐resolution 1H and 13C nmr techniques and force field and MNDO calculations.
Thiazolidine‐2,4‐dicarboxylic acid and its esters: Synthesis, in solution behaviour and regioselective cyclocondensation
Authors: Refouvelet Bernard , Robert Jean‐FranÇOis , Couquelet Jacques , Tronche Pierre 
Published: March 2009

AbstractThiazolidine‐2,4‐dicarboxylic acid 2 was obtained as a diastereoisomeric mixture from the condensation of glyoxylic acid with L(‐)R‐cysteine 1. In solution behaviour studies suggested that the reaction proceeded through an acid catalyzed epimerization mechanism. The methyl esterification of 2 was stereoselective, which can be explained by an interconversion of 2a via a ring seco intermediate. Condensation of the dimethyl ester 3 or the dissymmetric diester 4 with phenyl isocyanate gave rise to the same hydantoin 5. N‐acylation of diesters 3 or 4 followed by the reaction with benzylamine was regioselective leading to bicyclic derivatives 8‐10.
Synthesis of 1H‐ and 2H‐pyrazolo[3,4‐c][2,1]benzothiazepines
Authors: Diaz Juan A. , Vega Salvador 
Published: March 2009

AbstractStarting from ethyl chlorosulfonylpyrazole‐4‐carboxylates we have carried out the synthesis of ketones 3 and 4 which are the first two structures of the novel 1H‐ and 2H‐pyrazolo[3,4‐c][2,1]benzothiazepine ring systems.
Synthesis and anti‐hiv‐1 activities of 6‐arylthio and 6‐arylselenoacyclonucleosides
Authors: Pan Bai‐Chuan , Chen Zhi‐Hao , Piras Giovanna , Dutschman Ginger E. , Rowe Elizabeth C. , Cheng Yung‐Chi , Chu Shih‐Hsi 
Published: March 2009

Abstract6‐Arylthio and 6‐arylselenoacyclonucleosides was synthesized and tested for the ability to inhibit replication of HIV‐1. Lithiation of acyclonucleosides with LDA followed by reaction with the electrophiles phenyl disulfide, diphenyl diselenide, 2,2′‐dipyrdyl disulfide or 2,2′‐dipyridyl diselenide afforded 6‐(arylthio or arylseleno)acyclonucleosides 5a‐c, 6, 7, 9, 15a‐c, 17a‐c. Compounds 19a‐c and 20a‐c were obtained by deprotection of corresponding TBDMS derivatives. Dehydrated products 16a, and 18a‐c were also formed during the reactions. 5‐Ethyl‐6‐(α‐pyridylthio or α‐pyridylseleno) disubstituted acyclouracils 6 and 7 were more active against HIV‐1 in both MT‐2 and CEM‐IW cell lines than AZT, DDC, DDI or D4T. The EC50 of 6 against HIV‐1 in CEM‐IW cell was in the nanomolar range with a therapeutic index of 1100.