bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization and differentiation of heterocyclic isomers. Part 3. Study of high internal energy ions produced by electron ionization mass spectrometry on 3‐methyl‐1,2‐ and 2‐methyl‐1,3‐thiazolopyridines
Authors: Giorgi Gianluca , Salvini Laura , Ponticelli Fabio , Tedeschi Piero
Published: March 2009

The eight members of two classes of heterocyclic isomers, namely 3‐methyl‐1,2‐, 1a‐d and 2‐methyl‐1,3‐thiazolopyridines 2a‐d have been characterized by mass spectrometry under electron ionization. High internal energy ions formed in the source have been studied by low and high resolution mass spectrometry.

The data show remarkable differences among the various components of each class depending on the position of the nitrogen in the pyridine ring. Furthermore, by comparing the mass spectra of members of series 1 with those of their corresponding isomers belonging to series 2, it is still possible to obtain evidence for different behaviors in the fragmentation pathways. It seems to exclude the occurrence of inter‐conversion phenomena from one isomer into another, as well as conversion to a common intermediate before fragmentation. This also suggests that each member of series 1 and 2 retains its own structure after electron ionization.

The data obtained on a double focusing instrument equipped with electrostatic and magnetic analyzers have been compared with those obtained on a mass spectrometer with an ion trap as the analyzer.
New anti‐tumor agents. 2. Benzopyranylamine compounds
Authors: Jurd Leonard
Published: March 2009

Pyrrolidine, morpholine and piperidine derived Mannich bases of types 1–3 react with acetone, propionaldehyde and butyraldehyde to form 2‐methyl and 3‐methylbenzopyrans of types 4–8. Hydrolysis of these benzopyrans yields alcoholic benzopyrans which readily condense with a variety of amine, aniline and hydrazine derivatives to form diverse isomeric benzopyrans of types of 9 and 10. The benzopyrans 4–9 which contain a 3,4,5‐trimethoxyphenyl ring are active anti‐tumor agents, particularly against human breast, CNS and colon cancer cell lines, total growth inhibition of these tumors often occurring in vitro at concentrations as low as 10−5‐10−6 moles/1. Because of their in vitro activities and unusual structures a number of these benzopyrans have been selected for in vivo Xenograft testing against breast and other susceptible human cancers.
1‐(Mercaptomethyl)benzotriazole: Preparation, reactivity and synthetic utility
Authors: Katritzky Alan R. , Ghiviriga Ion , Oniciu Daniela C. , Soti Ferenc
Published: March 2009

A convenient synthesis is reported for 1‐(mercaptomethyl)benzotriazole (89%) and its reactivity is examined.
Syntheses of 1,2,4‐oxadiazole substituted pyrazole, isoxazole and pyrimidine heterocycles
Authors: Neidlein Richard , Li Sheng
Published: March 2009

Syntheses of two series of heterocyclic compounds having 1,2,4‐oxadiazole‐, together with pyrazole‐, isoxazole‐ or pyrimidine‐rings which have similar structures are reported. The mechanisms of the reactions are discussed.
Studies on pyrrolidones. Reactivity of β‐enaminoesters derived from pyroglutamic acid. Synthesis of methyl cyano[l‐methyl‐5‐(5‐methyl[1,3,4]oxadiazol‐2‐yl)pyrrolidin‐2‐ylidene]acetate
Authors: Fasseur Dominique , Cauliez Pascal , Couturier Daniel , Rigo Benoît , Defretin Sébastien
Published: March 2009

The 5‐methoxycarbonyl group of β‐enaminoesters derived from methyl pyroglutamate was transformed into acids, amides and 1,3,4‐oxadiazole.
The difference between the reactivities of azomethine bonds in metamitron in electrochemical and chemical reductions
Authors: Riedl František , Ludvík Jiří , Liška František , Zuman Petr
Published: March 2009

Electrochemical reduction of a herbicide metamitron (4‐amino‐3‐mefhyl‐6‐phenyl‐1,2,4‐triazin‐5(4H)‐one) in buffered aqueous solutions occurs on the protonated 1,6‐carbon‐nitrogen double bond. The 2,3‐double bond in the resulting 1,6‐dihydrometamitron is electrochemically reduced at considerably more negative potentials. In reaction with borohydride the 2,3‐double bond is reduced first. Reduction of the 1,6‐double bond is very little influenced by replacing the 2,3‐double bond by the ‐NHCH‐ grouping in 2,3‐dihydrometamitron.
Synthesis and central nervous system stimulant activity of camphor‐1,2,4‐benzotriazines fused with five and six‐membered heterocycles
Authors: Nagai Shin‐Ichi , Ueda Taisei , Takamura Masatoshi , Nagatsu Akito , Murakami Nobutoshi , Sakakibara Jinsaku
Published: March 2009

Novel camphor‐1,2,4‐triazines fused with imidazole 2–3, thiadiazole 4, 1,2,4‐triazole 7, pyrimidine 9–13 and 1,3,5‐triazine 14, were synthesized starting from (5R,8S)‐3‐amino‐5,9,9‐trimethyl‐5,6,7,8‐tetrahydro‐5,8‐methano‐1,2,4‐benzotriazine 1. Evaluation of central nervous system stimulant activity demonstrated that the presence of a N‐N group at C‐3 position of 1,2,4‐benzotriazine will be essential for the activity.
Synthesis of several deoxy analogues of pancratistatin
Authors: Balázs LÁSzlÓ , Kádas István , Tõke László
Published: March 2009

N‐Acetylated 1,4,7‐ and 3,4,7‐trideoxypancratistatin analogues 10 and 13 were synthesised from partially saturated phenanthridinones, 6 and 7, respectively via epoxidation and trans opening of the epoxides. Compounds 16 and 17, cis analogues of 13 were also synthesised from 7 via cis dihydroxylation with catalytic osmium tetroxide and N‐methylmorpholine N‐oxide. The stereoisomers obtained were separated by column chromatography after protection of the hydroxyl groups. The products synthesised are characterised satisfactorily by ir, nmr, ms and microanalysis data and are expected to possess anticancer or antiviral activity.
Synthesis of pyrido[2,3‐d]pyrimidines from aminopyrimidinecarbaldehydes
Authors: Perandones Francisco , Soto José L.
Published: March 2009

2‐Methoxy‐4‐amino‐5‐pyrimidinecarbaldehyde (2a) as well as its 6‐methyl 2b and 6‐phenyl derivatives 2c were prepared by reduction of the corresponding aminopyrimidinecarbonitriles 1. Catalytic hydrogenation of 1a, 1b gives 5‐hydroxymethylpyrimidines 3a, 3b; under the same conditions 1c afforded 5‐aminomethylpyrimidine 4. Condensation of 2 with carbonitriles, ketones and polyfunctional carbonyl compounds bearing the ‐CH2CO‐ moiety afforded the pyrido[2,3‐d]pyrimidines and pyrimido‐[4,5‐b]quinoline derivatives.
A novel synthesis of 14‐(hydroxymethylalkyl) derivatives of dibenzoxanthenes and 3,3‐dimethyl‐4‐(2‐hydroxy‐1‐naphthyl)benzo[f]chroman
Authors: Sirkecioǧlu Okan , Talinli Naciye , Akar Ahmet
Published: March 2009

Several reactions of 2‐naphthol with 2‐alkyl‐2‐hydroxymethylaldehydes have been investigated. Novel synthesis of 14‐(hydroxymethyl)alkyldibenzo[a,j]xanthenes and 3,3‐dimethyl‐4‐(2‐hydroxy‐1‐naphthyl)benzo[f]chroman has been realized.
The birch reduction of heterocyclic compounds. III. Birch reduction‐elimination reaction of 2‐ and 3‐furancarboxylic acid derivatives
Authors: Ohta Yasuo , Onoshima Man , Tamura Masumi , Tanaka Rika , Morimoto Yoshiki , Kinoshita Takamasa , Yoshihara Kazuo
Published: March 2009

The Birch reduction of 2‐(1‐alkoxyalkyl)furan‐3‐carboxylic acids 1a‐f gave 2‐alkyl‐3‐furancarboxylic acids 2a‐f with loss of the alkoxyl group in excellent isolated yields.
Fused imidazoacridines: Synthesis of 1,3‐dihydroimidazo[4,5‐b]‐acridin‐2‐one and 1,3‐dihydroimidazo[4,5‐a]acridin‐2‐one
Authors: Morel S. , Boyer G. , Galy J.‐P.
Published: March 2009

The synthesis of new 1,3‐dihydroimidazo[4,5‐a]acridin‐2‐one and 1,3‐dihydroimidazo[4,5‐b]acridin‐2‐one derivatives is reported. The yield and the structure of each isomer were determined by nmr spectroscopy.
Synthesis of novel pyrrolidin‐2‐ones: γ‐aminobutyric acid cyclic analogues
Authors: Ebrik S. Al Akoum , Rigo B. , Vaccher C. , Vaccher M‐P. , Flouquet N. , Debaert M. , Berthelot P.
Published: March 2009

Some new N‐substituted pyrrolidin‐2‐ones, cyclic analogues of baclofen and of 3‐(5‐methoxybenzo‐[b]furan‐2‐yl)‐γ‐aminobutyric acid, have been prepared and characterized, starting from 4‐(4‐chlorophenyl)‐pyrrolidin‐2‐one and 4‐(5‐methoxybenzo[b]furan‐2‐yl)pyrrolidin‐2‐one.
Synthesis of novel pyridazino[4,5‐b][1,4]oxazine‐3,5‐diones
Authors: Cho Su‐Dong , Kweon Deok‐Heon , Kang Young‐Jin , Chung Hyun‐A , Yoon Yong‐Jin
Published: March 2009

Novel pyridazino[4,5‐b][1,4]oxazine‐3,5‐diones were synthesized from N‐[2‐(3,4‐dimethoxyphenyl)‐ethyl]‐2‐chloroacetamide (or 2‐chloropropanamide) and 1‐alkyl‐5‐halo‐4‐hydroxypyridazin‐6‐ones in good yield.
Isoquinolinium N‐arylimides and strained cycloalkenes
Authors: Temme Robert , Huisgen Rolf
Published: March 2009

In contrast to common alkenes and enol ethers, the angle‐strained double bonds of norbornene, dimethyl norbornadiene‐2,3‐dicarboxylate, and acenaphthylene undergo [3+2] cycloadditions with isoquinolinium N‐arylimides. The structures of the crystalline adducts have been elucidated from their 1H nmr spectra.
Synthesis and properties of cyclohepta[cd]benzothiophenes
Authors: Horaguchi Takaaki , Kubo Takuji , Tanemura Kiyoshi , Suzuki Tsuneo
Published: March 2009

Cyclohepta[cd]benzothiophene 3, a new heterocyle, was synthesized starting from benzothiophene via eight steps in 14% total yield. Chemical reactions of 3 were examined on formylation, acetylation, bromination, catalytic hydrogenation and Diels‐Alder reactions. The results show that the benzothiophene moiety of 3 has aromatic character and the carboncarbon double bonds in a seven‐membered ring posseses alkene‐1ike character.
Simple synthetic route to polyhydroxylated pyrrolidines and piperidines
Authors: Lee Sang Gyeong , Yoon Yong‐Jin , Park Ki Hun
Published: March 2009

A short and simple synthetic route to polyhydroxylated piperidines and pyrrolidines were described with D‐glucurono‐δ‐lactone as chiral educt. Key reaction steps included selective cleavage of terminal isopropylidene group of compound 12 with Dowex 50W‐X8 resin (H+ form), regioselective ring opening of epoxide 16 and intramolecular nucleophilic amination of compound 14 and 18.
Towards lipophilic derivatives of S‐adenosyl‐L‐methionine
Authors: Juanes Olga , Goya Pilar , Martinez Ana
Published: March 2009

Two different strategies for the synthesis of S‐Adenosyl‐L‐methionine liphophilic derivatives have been attempted. The first chemical direct modification performed on S‐adenosyl‐L‐methionine is described.
Steroidal isoxazoles, isoxazolines and isoxazolidines
Authors: Camoutsis Ch. , Nikolaropoulos S.
Published: March 2009

The present review considers new useful heterocyclosteroids which contain five‐membered heterocyclic systems, namely, isoxazoles, isoxazolines and isoxazolidines, condensed to the cyclopentanoperhy‐drophenanthrene skeleton, in different positions of the molecule, with changes in their physiological activity and the appearance of new interesting biological properties. Literature coverage for the review includes publications up to the end of 1996.
Ring transformations of heterocyclic compounds. XVI. Spiro[cyclohexadiene‐dihydroacridines]. A novel class of spirodihydroacridines by ring transformation of pyrylium salts with 9‐methylacridine and its quaternary salts
Authors: Zimmermann Thomas , Abram Ulrich , Schmidt Klaus
Published: March 2009

2,4,6‐Triarylpyrylium salts 1 react with the in situ generated anhydrobase of 9,10‐dimethylacridinium methosulfate (2a) in the presence of anhydrous sodium acetate in ethanol by a 2,5‐[C4+C2] pyrylium ring transformation to give the hitherto unknown 6‐aroyl‐3,5‐diaryl‐10′‐methylspiro[cyclohexa‐2,4‐diene‐1,9′‐9′,10′‐dihydro‐acridines] 3. When the pyrylium perchlorate 1a is treated under the same conditions with the N‐ethyl, N‐allyl or N‐benzyl substituted acridinium salts 2b‐d a dealkylation of these salts occurs and the N‐unsubstituted spiro[cyclohexadiene‐dihydroacridine] 4a is formed. The same compounds 4 can also be obtained by transformation of the pyrylium salts 1 with 9‐methylacridine (7) and triefhylamine/acetic acid in ethanol. Structure elucidation is performed by an X‐ray crystal structure determination of the spiro[cyclohexadiene‐dihydroacridine] 3a. Spectroscopic data of the transformation products and their mode of formation are discussed.
Computational study of ethylene, acetylene, and cyclopropene addition to heterocycles with two heteroatoms in the 1,2 position
Authors: Jursic Branko S.
Published: March 2009

The AM1 semiempirical and B3LYP density functional theory computational studies are undertaken with the target being to explore cycloaddition reactions with heterocycles that have two heteroatoms in the ring's 1 and 2 positions as an initial synthetic step in the preparation of allene's acetylene derivatives. Several qualitative computational approaches were used to evaluate the heterocycle reactivity, including two new approaches using electronic and bond order changes in transformation of the reactant pair into corresponding transition state structures. Finally, the reactivity was evaluated by computing activation barriers, and the feasibility of the proposed synthetic transformations was discussed.
A facile synthesis of cyanophenothiazines
Authors: Marivingt‐Mounir Céacile , Mettey Yvette , Vierfond Jean‐Michel
Published: March 2009

A one‐pot synthesis of 1, 3 and 4‐cyanophenothiazines and a two‐step approach to 2‐cyanoisomer have been developed. The condensation of 2‐aminobenzenethiol and 2,3 or 3,4‐dihalogenobenzonitriles followed by Smiles rearrangement or by intramolecular aromatic substitution gave the desired ring systmes.
Pyrolysis and photolysis of 1‐aroylamino‐4,5‐diaryl‐1,2,3‐triazoles: Generation and thermal transformations of 4,5‐diaryl‐1,2,3‐triazolyl radicals
Authors: Hadjiantoniou‐Maroulis C. P. , Charalambopoulos A. Ph. , Maroulis A. J.
Published: March 2009

The pyrolysis of 1‐aroylamino‐4,5‐diphenyl‐1,2,3‐triazoles 1 yields, pressumably via the 4,5‐diphenyl‐1,2,3‐triazolyl radical (2a), 2,3‐diphenyl‐2H‐azirine (11a) and 2‐aryl‐4,5‐diphenylimidazoles 14 as the major products. Upon irradiation 1‐benzoylamino‐4,5‐diphenyl‐1,2,3‐triazole (1a) gives 4,5‐diphenyl‐1 (2)H‐1,2,3‐triazole (4a) via the 1,2,3‐triazolyl radical 2a, together with benzamide (5a) and 1,2‐bisbenzoylhydrazine (6a). Products 5a and 6a result from the benzoylamino radical 3a by hydrogen atom abstraction and dimerization respectively.
Synthesis of hydroxy‐substituted aza‐analogues of antitumor anthrapyrazoles
Authors: Krapcho A. Paul , Gallagher Cynthia E. , Hammach Abdelhakim , Hacker Miles P. , Menta Ernesto , Oliva Ambrogio , Di Domenico Roberto , Da Re Giovanni , Lotto Andrea , Spinelli Silvano
Published: March 2009

Synthetic routes have been developed which lead to ring‐hydroxylated aza‐analogues of antitumor anthrapyrazoles, namely, 2,5‐bis[(aminoalkyI)amino] substituted 10‐hydroxymdazolo[3,4‐fg]isoquinolin‐6(2H)‐ones 1 and 7‐hydroxyindazolo[4,3‐gh]isoquinolin‐6(2H)‐ones 2. The regiospecific synthesis of 6,9‐dihalo‐4‐hydroxybenz[g]isoquinolines 3 and 4 has been accomplished. Intermediate 3 was constructed in a multistep process involving Diels‐Alder chemistry of benzoylacrylates whereas 4 was assembled using Ni(II) mediated coupling of methyl 3‐chloro‐5‐methoxyisonicotinate (15b) with the organic zinc reagent 18 derived from 2‐fluoro‐5‐chlorobenzyl bromide (17). After protection of the hydroxy group with a p‐methoxybenzyl moiety, the different nucleofugacities of the leaving groups present in 10 and 20 allowed sequential displacements by substituted hydrazines and amines, respectively, to lead to the desired p‐methoxybenzyl protected analogues 12 and 22. Deprotection led to the side arm modified compounds 1 and 2. The displacements of 21a and 21b with N,N‐dimethylethylenediamine also led to the tri[(aminoalkyl)amino]substituted analogues 23a and 23b, respectively, which arose from further SNAr substitutions of the p‐methoxybenzyloxy group.
Synthesis of a new decahydrohexapyrrin of biosynthetic interest
Authors: Kogan Marcelo J.
Published: March 2009

A new decahydrohexapyrrin containing a tert‐butoxycarbonylbilane of type III was prepared applying a convergent type synthesis. The order of the side chains of the tert‐butoxycarbonylbilane belonging to this oligopyrrole corresponds to that of a type HI uroporphyrinogen. A symmetric hexapyrrol dilactam was formed as a by product of the synthesis.
Synthesis of thienoimidazothiazoles
Authors: Binder Dieter , Pyerin Michael , Schnait Heinz
Published: March 2009

Three isomeric substituted thienoimidazothiazoles were synthesized as thiophene analogs of the immune modulator TILOMISOL, by cyclizing appropriate β‐oxothioethers of thienoimidazoles. In contrast to the benzene analog no intermediates were observed at this step.
Synthesis of novel heterocycles from 2‐amino‐3‐(cyanomethylsulfonyl)thiophene
Authors: Stephens Chad E. , Sowell J. Walter
Published: March 2009

The synthesis and selected reactions of 2‐amino‐3‐(cyanomethylsulfonyl)thiophene is reported. In particular, cyclization reaction of the versatile aminothiophene yielded a number of novel thieno[3,2‐b][1,4]‐thiazine 1,1‐dioxides, as well as the analogous thieno[2,3‐e][1,3,4]thiadiazine 4,4‐dioxide. Reaction of the thienothiazine system with hydrazine was subsequently explored, which resulted in either ring‐opening of the thiazine and formation of an aminopyrazole or solely ring cleavage depending on the thiazine substituent. Additionally, the synthesis of bis(2‐amino‐3‐thienyl)sulfone and the corresponding bis‐acetamide is described.
The synthesis of 3‐[(dimethylamino)(2‐phenyl‐5‐oxo‐2‐oxazolinyl‐idene‐4)methyl]imidazo[1,2‐x]azines and related compounds, intermediates in the formation of azaaplysinopsin derivatives
Authors: Bratušek Urška , Hvala Aleš , Stanovnik Branko
Published: March 2009

4‐(2‐Bromo‐1‐dimethylaminoethylidene)‐2‐phenyl‐5(4H)‐oxazolone (5) reacts with N,N‐dimethyl‐N'‐heteroarylformamidines 7 to form imidazoazine derivatives 9 with the oxazolone ring connected through a conjugated double bond to the fused imidazole system at position 3. Compounds 9 were transformed with sodium methoxide in methanol into 2‐benzoylamino‐3‐dimethylamino‐3‐imidazoazinylpropenoates 10, while by treatment with hydrochloric acid in methanol, 3‐(benzoylaminoacetyl)imidazoazines 12 were formed. The synthesis of compounds 9 represents a facile route to intermediates in the synthesis of azaaplysinopsin and related systems.
Synthesis and application of ethyl 2‐arylazo‐4,9‐dioxonaphtho[2,3‐b]thiophene‐3‐carboxylate
Authors: Rangnekar D. W. , Kanetkar V. R. , Shankarling G. S. , Malanker J. V.
Published: March 2009

Synthesis of ethyl 2‐arylazo‐4,9‐dioxonaphtho[2,3‐b]thiophene‐3‐carboxylate was achieved by diazotization of ethyl 2‐amino‐4,9‐dioxonaphtho[2,3‐b]thiophene‐3‐carboxylate and coupling with selected N,N‐dialkylanilines. The key intermediate ethyl 2‐amino‐4,9‐dioxonaphtho[2,3‐b]thiophene‐3‐carboxylate was synthesized by the condensation of sodium salt of ethyl cyanoacetate with 2,3‐dichloro‐1,4‐naphthoquinone. Ethyl 2‐arylazo‐4,9‐dioxonaphtho[2,3‐b]thiophene‐3‐carboxylate were applied on polyester fibers as disperse dyes and their dyeing properties were studied.
Knoevenagel reaction of malononitrile with methyl ketone followed by double cyclization catalyzed by potassium fluoride‐coated alumina
Authors: Nakano Yoshiharu , Shi Wei‐Ying , Nishii Yoshiyuki , Igarashi Minoru
Published: March 2009

Qualitative limitations were presented for a formation reaction of a series of bridged compounds from ketones and malononitrile catalyzed with potassium fluoride‐alumina in acetonitrile [1]. The bridged com pounds were obtained from only unhindered alkyl methyl ketones. The compounds released hydrocarbon to give pyridine derivatives.
Controlling substitution patterns on the 1,2,4‐triazolo[1,5‐α]‐pyrimidine ring. Selective removal of chlorine at the 7‐position
Authors: Monte William T. , Kleschick William A. , Bordner Jon
Published: March 2009

A highly effective method for the selective removal of chlorine from the 7‐position of the 1,2,4‐triazolo[1,5‐α]pyrimidine ring in the presence of chlorine at the 5‐ or 6‐positions is reported. The method involves treatment of the appropriate substrate with zinc‐copper couple in the presence of acetic acid in methanol‐tetrahydrofuran. The method enables the construction of a variety of substitution patterns in key intermediates for the 1,2,4‐triazolo[1,5‐α]pyrimidine sulfonanilide herbicides.
Thermal and photochemical reaction of isoxazolone with indole‐2,3‐dione derivatives
Authors: Pardasani R. T. , Pardasani P. , Muktawat S. , Ghosh R. , Mukherjee T.
Published: March 2009

The reaction of indole‐2,3‐dione derivatives with five membered heterocycle, viz isoxazolone under ther mal as well as photochemical conditions is described. While under refluxing ethanol these conditions afforded 2,3‐dihydro‐3‐(5′‐oxo‐3′‐phenylisoxazolidyl)indol‐2‐one 3 and a spiro product 2′,3′‐dihydro‐3,7‐diphenylspiro[diisoxazolo[4,5‐e:4,5‐b]pyran‐8,3′‐indol]‐2′‐one 4, the uv light induced irradiation mainly produced 4,5‐dioxo‐3‐phenylisoxazolo[5,4‐b][1]benzazepine 5 and 3‐phenylisoxazolo[5,4‐b]quinoline‐4‐carboxylic acid 6. The products have been characterised on the basis of spectral data and elemental analyses.
Synthesis and mechanism of formation of novel 2,5‐dihydro‐2,5‐diimino‐3,4‐di[(N,N‐dimethylamino)methylideneamino]pyrroles and 5‐amino‐3,4‐di[(N,N‐dimethylamino)methylideneamino]‐2H‐2‐iminopyrroles
Authors: Alves M. José , Carvalho M. Alice , Fernanda M. , Proença J. R. P. , Booth Brian L. , Pritchard Robin G.
Published: March 2009

Formation of 5‐amino‐3,4‐di[(N,N‐dimethylarnino)methylidenearnino]‐2H‐2‐iminopyrroles 3 from the reaction of (Z)‐N1‐(2‐amino‐1,2‐dicyanovinyl)‐N2‐substituted‐formamidines 1 with dimethylformamide diethyl acetal has been shown to occur by initial formation of (Z)‐N1‐{l,2‐dicyano‐2‐[N,N‐dimethylamino)methylideneamino]vinyl}formamidines 8 (isolated), followed by base catalysed cyclisation and imi dazole ring opening by dimethyl amine. The kinetic product of the ring opening reaction is the 2,5‐diimino2,5‐dihydropyrrole derivatives 11, which have been isolated and characterized spectroscopically and by a single crystal X‐ray analysis on the R = Ph derivative. In solution at room temperature the N‐aryl derivatives undergo a rapid Dimroth rearrangement to give the thermodynamic ally more stable isomer 3, but compound 11 (R = Me) is much more stable in solution.
Conformationally locked heterocycles. Structure of a doubly bridged pyrimido[1,2‐a]pyrimidine from the hantzsch synthesis with 4‐(2‐hydroxyphenyl)but‐3‐en‐2‐one
Authors: Světlík Jan , Liptaj Tibor , Tureček FrantiŠEk
Published: March 2009

1D and 2D nmr spectroscopy was used to assign the structure to the minor product from cyclocondensation of 4‐(2‐hydroxyphenyl)but‐3‐en‐2‐one with cyanamide, which was identified as (6R*, 9R*, 15R*, 17R*)‐6,9‐dimethyl‐6,17:9,15‐dimemano‐6H,15H,17H‐[1,3,5]benzoxadiazocino[4,5‐d][1,3,5]benzoxadiazocine‐7(9H)‐carbonitrile, a doubly oxygen‐bridged pyrimido[1,2‐a]pyrimidine derivative. The observed stereose lectivity and reaction mechanisms are discussed with the help of molecular mechanics and semi‐empirical PM3 calculations.
The synthesis of methyl 2‐(benzyloxycarbonyl)amino‐3‐dimethylaminopropenoate. The synthesis of trisubstituted pyrroles, 3‐amino‐2H‐pyran‐2‐ones, fused 2H‐pyran‐2‐ones and 4H‐pyridin‐4‐ones
Authors: Toplak Renata , Svete Jurij , Stanovnik Branko , Grdadolnik Simona GoliČ
Published: March 2009

Methyl 2‐(benzyloxycarbonyl)aimno‐3‐dimemylaminopropenoate (2) was prepared from methyl N‐(benzyloxycarbonyl)glycinate (1) and t‐butoxybis(dimethylamino)methane, and used as a reagent for preparation of substituted 3‐(benzyloxycarbonyl)amino‐4H‐quinolizin‐4‐ones 5 and 6, −2H‐pyran‐2‐ones 17–19, −2H‐1‐benzopyran‐2‐ones 28–31, and ‐naphthopyrans 32–35, −2H‐pyrano[3,2‐c]pyridine‐2,5‐dione 46, ‐pyrano‐[4,3‐b]pyran‐2,5‐dione 47, ‐pyrano[3,2‐c]benzopyran‐2,5‐dione 48, ‐pyrano[2,3‐c]pyrazol‐6‐ones 49 and 50, ‐pyrano[2,3‐d]pyrirnidin‐7‐ones 51 and 52 derivatives. In the reaction of 2 with 1,3‐diketones trisubsti tuted pyrroles 14–16 were formed. Selective removal of benzyloxycarbonyl group was achieved by cat alytic transfer hydrogenation with Pd/C in the presence of cyclohexene to afford free 3‐amino compounds 7, 8, 20, 36–38 and 53–57 in yields better than 80%.
Thermal rearrangement of 1,3‐thiazolidine sulfoxides: Thiolsulfinate and thioaldehyde intermediates
Authors: Hahn Hoh‐Gyu , Nam Kee Dal , Mah Heduck
Published: March 2009

Stereospecific ring opening of the sulfoxides cis‐13 and trans‐14 in refluxing toluene gave the corre sponding sulfenic acids 9, 10 intermediates respectively. The sulfenic acid 9 dimerized to the thiolsulfinate 17 by dual function of the sulfenic acid as S‐nucleophile/S‐electrophile with loss of water while the sulfenic acid 10 was unchanged. The stereospecific recyclization of 10 to the parent sulfoxide 14 increases the higher pi‐electron density of the double. The thermolysis of the thiolsulfinate 17 gave the transient sulfenic acid 9, which dimerized again to repeat the process and unisolable thioaldehyde 21. The thioaldehyde 21 was con verted to either pyrrole 15 by the action of a sulfinic acid 20 catalyst formed inevitably by hydrolysis of 17 under the reaction conditions, or thiazole 18 under neutral conditions. In these rearrangements, the amide carbonyl group facilitated the elimination of a neighboring hydrogen.
Rearrangement of 2‐amino‐4‐(trifluoromethyl)oxazoles to hydantoins
Authors: Lawson Jon P. , VanSant Karey A.
Published: March 2009

Reaction of 2‐amino‐4‐trifluoromethyloxazoles with excess bromine in acetic acid/sodium acetate gives 5‐acetoxyhydantoins. The 5‐bromooxazoles are intermediates in the reaction.
7‐Deaza‐5′‐noraristeromycin derivatives resembling L‐toyocamycin and L‐sangivamycin
Authors: Seley Katherine L. , Schneller Stewart W.
Published: March 2009

The synthesis of the 7‐cyano and 7‐carboxamido derivatives of 7‐deaza‐5′‐noraristeromycin have been prepared in 3 and 4 steps, respectively, for evaluation as anti‐trypanosomal agents. Neither compound was active in the latter assay.
Palladium‐catalyzed synthesis of 3‐oxo‐1,3‐dihydro‐1‐isobenzofuranyl alkanoates from 2‐bromobenzaldehyde and sodium alkanoates
Authors: Cho Chan Sik , Baek Dong Yeol , Shim Sang Chul
Published: March 2009

2‐Bromobenzaldehyde reacts with sodium alkanoates in acetonitrile under carbon monoxide pressure in the presence of a catalytic amount of bis(triphenylphosphine)palladium(II) chloride to afford the corre sponding 3‐oxo‐1,3‐dihydro‐1‐isobenzofuranyl alkanoates in moderate to good yields.
A slightly shorter route to carbocyclic nucleosides. Synthesis of (±)‐trans‐1‐[2‐(hydroxymethyl)cyclopentylmethyl]uracil
Authors: Santana Lourdes , Teijeira Marta , Uriarte Eugenio
Published: March 2009

(±)‐trans‐1‐[2‐(Hydroxymethyl)cyclopentylmethyl]uracil (1) was prepared in two steps and 56% yield from 2‐hydroxymethylcyclopentylmethylamine (7) and 3‐methoxy‐2‐propenoylisocyanate (6). Isocyanate 6 was prepared from methyl 3‐methoxy‐2‐propenoate in four steps and 38% overall yield.
Synthesis of spiroisoindolinones by palladium‐catalyzed heterocyclization of 2‐iodobenzoyl chloride with ketimines
Authors: Cho Chan Sik , Wu Xue , Jiang Li Hong , Shim Sang Chul , Kim Hong Rak
Published: March 2009

2‐Iodobenzoyl chloride reacts with ketimines in acetonitrile at 100° under carbon monoxide pressure in the presence of a catalytic amount of a palladium catalyst together with triethylamine to afford the corresponding spiroisoindolinones in high yields.
Unusual dihydrazone formation in the fischer‐indole cyclization. The synthesis of novel nonclassical annulated 2,4‐Diamino‐pyrrolo[2,3‐d]pyrimidine antifolates
Authors: Gangjee Aleem , Chen Lihua
Published: March 2009

The synthesis of seven novel tetracyclic 2,4‐diaminopyrrolo[2,3‐d]pyrimidines as conformationally restricted nonclassical antifolates was achieved via an unusual Fischer‐indole cyclization of dihydrazones. An attempted synthesis of 2,4‐diamino‐6‐hydrazinopyrimidine afforded 2‐amino‐4,6‐dihydrazinopyrimidine which when reacted with appropriate ketones gave the dihydrazones. The dihydrazones in turn under Fischer‐indole cyclization conditions afforded target conformationally restricted tetracyclic products.
Exploratory chemistry of 3‐aroylformamido‐4‐aryl‐1,2,5‐thiadiazoles
Authors: Kong Yung Cheol , Kim Kyongtae
Published: March 2009

Apart from the previous report, the reaction of 3‐(4‐nitrobenzoylformamido)‐4‐(4‐nitrophenyl)‐1,2,5‐thiadiazole (2a) with m‐chloroperbenzoic acid in chloroform at room temperature did not proceed, whereas at reflux temperature the same reaction gave 4‐nitrobenzoic acid (5) (86%) and a minute amount of a mixture of 4‐nitrobenzoylformamide (6) and 3‐amino‐4‐(4‐nitrophenyl)‐1,2,5‐thiadiazole (7a). On the other hand the same reaction in a mixture of ethanol and chloroform (1:4) at room temperature gave 3‐ethoxycarbamoyl‐4‐(4‐nitrophenyl)‐1,2,5‐thiadiazole (8a) (24%) as an isolable product. When 3‐aroylformamido‐4‐aryl‐1,2,5‐thiadiazoles 2 in tetrahydrofuran were treated with various alkoxides in the corresponding alcohols at room temperature, 3‐amino‐4‐aryl‐ 7, 3‐alkoxycarbamoyl‐4‐aryl‐ 8, and 3‐aryl‐4‐(aryl)(hydroxy)acetamido‐1,2,5‐thiadiazoles 9 were isolated. The ratios of which were dependent on the kind of bases and the solvent employed. Selected compounds 2 were allowed to react with phosphorus pentasulfide in the presence of pyridine at reflux to give 3‐aryl‐4‐arylacetarnido‐1,2,5‐thiadiazoles 17 (55–64%), which were also produced by the reaction of 2 with either Lawesson's reagent or hydrogen sulfide gas in the presence of pyridine at reflux.
A Comparison of the hyphenated experiments GHMQC‐TOCSY and GHSQC‐TOCSY
Authors: Hadden Chad E. , Martin Gary E. , Luo J.‐K. , Castle Raymond N.
Published: March 2009

Heteronuclear shift correlations generally may be established using either the multiple quantum‐based GHMQC experiment or, alternately, the single quantum‐based GHSQC experiment. A scant few reports contained in the literature have compared results obtained with both types of sequences. The F1 resolution of the GHMQC and GHSQC experiments are compared using the polynuclear heteroaromatic naphtho‐[2′,1′:5,6]naphtho[2′,1′:4,5]thieno[2,3‐c]quinoline. Even when augmented by linear prediction in F1, the single quantum‐based GHSQC sequence gives better F1 resolution than its multiple quantum counterpart. To date, no studies have compared the hyphenated analogs of these experiments, GHMQC‐ and GHSQC‐ TOCSY. Similar conclusions to GHMQC/GHSQC are drawn for the comparison of GHMQC‐ and GHSQC‐ TOCSY experiments with inverted direct responses with, and without, linear prediction. The latter is recommended whenever there is congestion in both the F2 and F1 frequency domains.
Reductive cyclization of carbohydrate 2‐nitrophenylhydrazones to chiral functionalized 1,2,4‐benzotriazines and benzimidazoles
Authors: Andersch Jens , Sicker Dieter
Published: March 2009

The 2‐nitrophenylhydrazones 2 of D‐arabino‐2‐hexulopyranosonic acid, D‐arabinose, D‐galactose and D‐galacturonic acid are used as precursors to form chiral functionalized 1,2,4‐benzotriazines and benzimidazoles by reductive cyclization methods. Catalytic hydrogenation provided the amine derivatives which are cyclized and air oxidized in alkaline solution to yield the novel 1,2,4‐benzotriazines 3 as the main products, while on acid catalysis the benzimidazoles 4 are formed.
An alternative synthesis of piritrexim, a lipophilic inhibitor of human dihydrofolate‐reductase
Authors: Troschütz Reinhard , Zink Mario , Gnibl Rainer
Published: March 2009

An alternative synthesis of the lipophilic antifolate piritrexim (1) is outlined. Starting from ketone 2, treatment with phosphorus oxychloride and dimethylformamide gave the β‐chlorocrotonaldehydes 3E/Z, which were reacted with cyanoacetamide (6) in the presence of sodium hydride to yield a 3‐cyano‐2‐pyridone derivative 7. Chlorination of 7 with thionyl chloride and subsequent reaction with guanidine (9) gave rise to piritrexim (1). The reaction of β‐chlorocrotonaldehydes 3E/Z, with 2,4,6‐triaminopyrimidine (4) yielded iso‐piritrexim (5).
One‐step synthesis of novel 2,4‐diaminopyrimidine antifolates from bridged alicyclic ketones and cyanoguanidine
Authors: Rosowsky Andre , Papoulis Andrew T. , Queener Sherry F.
Published: March 2009

A convenient one‐step reaction with cyanoguanidine was used to convert alicyclic ketones to previously undescribed 2,4‐diamino‐5,6,7,8‐tetrahydroquinazolines with a one‐, two‐, or three‐carbon bridge in the carbocyclic ring. Although the yields of the desired products were modest, the principal advantage of this one‐step process was that it provided easy access to a variety of novel bridged heterocyclic ring systems whose synthesis from sterically hindered ketones by other methods would have required multiple steps with an even lower overall yield. The products were tested as inhibitors of dihydrofolate reductases from Pneumocystis carinii, Toxoplasma gondii, and rat liver with a view to examining the effect of a space‐filling bridge on binding. The most potent and selective compound in the group was 4,6‐diamino‐3,5‐diazatricyclo[7.2.1.02,7]dodeca‐2,4,6‐triene (13), whose potency and selectivity approached those of trimethoprim, a drug commonly used to treat P. carinii and T. gondii infection. 3,5‐Diamino‐4,6‐diazatricyclo[6.2.1.02,7]‐undeca‐2,4,6‐triene (14), the analog of 13 with a one‐carbon rather than a two‐carbon bridge showed similar potency and selectivity against the T. gondii enzyme, but was a weak and nonselective inhibitor of P. carinii dihydrofolate reductase. The other compounds tested were likewise weak and nonselective.
Ring transformation of 3‐halo‐4‐methoxycoumarins into pyrazoles with hydrazines
Authors: Morita Hikari , Harada Kazuho , Okamoto Yoshihisa , Takagi Kaname
Published: March 2009

3‐Chloro‐ and 3‐bromo‐4‐methoxycoumarins 1a,b were readily transformed into 4‐halo‐5‐(2‐hydroxyphenyl)‐3‐oxo‐2,3‐dihydropyrazoles 2a,b with hydrazines. In the reaction of 1a,b with excess hydrazine and phenylhydrazine in boiling ethanol, unexpected 4‐hydrazono‐3‐(2‐hydroxyphenyl)‐2‐pyrazolin‐5‐ones 3, 5 were obtained. The structure of 3 was determined by X‐ray diffraction analysis.
Syntheses of diaza‐18‐crown‐6 ligands containing two units each of 4‐hydroxyazobenzene, benzimidazole, uracil, anthraquinone, or ferrocene groups
Authors: Su Ning , Bradshaw Jerald S. , Zhang Xian X. , Savage Paul B. , Krakowiak Krzysztof E. , Izatt Reed M.
Published: March 2009

Six new diaza‐18‐crown‐6 ligands each containing two aromatic side arms with responsive functions were prepared. Diaza‐18‐crown‐6 containing two 4‐hydroxyazobenzene (3) or two 4‐hydroxy‐4′‐(dimethyl‐amino)azobenzene (4) substituents were prepared via a one‐pot Mannich reaction. Diaza‐18‐crown‐6 containing two benzimidazole (5), two uracil (6) or two 9,10‐anthraquinone (7) substituents were prepared by treating the diazacrown with the appropriate chloromethyl‐containing compound. Reductive amination using sodium triacetoxyborohydride, diaza‐18‐crown‐6 and ferrocenecarboxaldehyde was used to prepare bisferrocene‐substituted diaza‐18‐crown‐6 (8). Interactions of compounds 3, 5, and 6 with Na+, K+, Ba2+, Ag+, and Cu2+ were evaluated by a calorimetric titration technique at 25° in methanol. All three ligands form more stable complexes with Ag+ and Cu2+ (5 forms a precipitate with Ag+) than with Na+ and K+. Ligand 5 also forms a highly stable complex with Ba2+.
An efficient general synthesis of 1‐(benzotriazol‐1‐yl)alkyl esters
Authors: Katritzky Alan R. , Pastor Alfredo , Voronkov Michael V.
Published: March 2009

1‐(Benzotriazol‐1‐yl)alkyl esters 2a‐u were obtained in yields averaging 86% by the direct reaction of various aldehydes with the corresponding N‐acylbenzotriazoles in the presence of a catalytic amount of potassium carbonate (10–25 mole %). The procedure was optimized by evaluating the effects of solvent, catalyst, temperature and other parameters.
Oxidative ring‐opening of rel‐(2R,3R,5S)‐5‐aryl‐2‐benzoylamino‐6,7‐bis(methoxycarbonyl)‐2,3‐dihydro‐1‐oxo‐3‐phenyl‐1H,5H‐pyrazolo[1,2‐a]‐pyrazoles. Synthesis of rel‐(2R,3R)‐3‐phenyl‐3‐[5‐aryl‐3,4‐bis(methoxycarbonyl)pyrazolyl‐1]alanine esters
Authors: Prešeren Andrej , Svete Jurij , Stanovnik Branko
Published: March 2009

rel‐(2R,3R)‐N‐Benzoylamino‐6,7‐bis(methoxycarbonyl)‐2,3‐dihydro‐1‐oxo‐1H,5H‐pyrazolot[1,2‐a]‐pyrazoles 5, accesible by cycloaddition of dimethyl acetylenedicarboxylate (3) to (1Z)‐rel‐(4R,5R)‐1‐aryl‐methylidene‐4‐benzoylamino‐5‐phenyl‐3‐pyrazolidinone‐1‐azomethine imines 4, undergo oxidative ring cleavage with methanolic bromine giving rel‐(2R,3R)‐N‐benzoyl‐3‐phenyl‐3‐[5‐aryl‐3,4‐bis(methoxy‐carbonyl)pyrazolyl‐1]alanine methyl esters 6 as products.
Synthesis of polyazacyclophane‐intercalator conjugates for combinatorial chemistry and RNA interaction studies
Authors: Wang Tingmin , An Haoyun , Haly Becky D. , Dan Cook P.
Published: March 2009

Anthraquinone and pyrene intercalators were conjugated to different positions of several polyaza‐pyridinocyclophanes by various linkers to provide thirteen new polyazacyclophane‐intercalator conjugates 1–13. These resulting conjugates contain two or three constrained secondary nitrogen atoms on the ring, which may serve as nucleophilic, coordinating or hydrogen‐bonding sites for combinatorial, RNA interaction and coordination studies.
Synthesis of 1,2‐oxazaheterocycles containing an isoindolone moiety from N‐Hydroxyphthalimide
Authors: Bartovic Alexander , Decroix Bernard , Netchitaïlo P.
Published: March 2009

Syntheses of the isoindolobenzoxazinone 1a and thienoxazinoisoindolones 1b,c was developed from N‐hydroxyphthalimide 3 and halogenomethylaryl derivatives. The resulting aryloxy phthalimides 4a‐c were reduced to hydroxylactams 5a‐c which cyclized in acidic conditions. A Wittig reaction on 5a using carbethoxymethylidenetriphenylphosphorane gave the corresponding acid 6 which treated in Friedel and Crafts conditions led to the isoxazolinone 8 by cleavage of the benzyl CO bond.
Lipase‐catalysed kinetic resolution of hydroxymethylchromanes
Authors: Czompa A. , Kovács T. , Antus S.
Published: March 2009

An effective kinetic resolution of hydroxymethylchromanes racemic 2a and 3a has been achieved by means of enantioselective transesterification with vinyl acetate in organic solvents. The alcohols (‐)‐R‐2a and (‐)‐S‐3a were obtained with high optical purities (94 and 98% ee) in 70% and 38% yields, respectively. The influence of the enzyme source and the character of the solvent on the enantioselectivity were studied.
Synthesis of novel, nonclassical 2‐amino‐4‐oxo‐6‐(arylthio)ethylpyrrolo[2,3‐d] pyrimidines as potential inhibitors of thymidylate synthase
Authors: Gangjee Aleem , Dubash Nauzer P. , Kisliuk Roy L.
Published: March 2009

A novel series of 14 nonclassical 6‐substituted pyrrolo[2,3‐d]pyrimidines 2a ‐ 2n were designed as potential inhibitors of thymidylate synthase, based on previously reported 2‐amino‐4‐oxopyrrolo[2,3‐d]‐pyrimidines 1a and 1b. The synthesis of the target compounds 2a‐2n was accomplished by nucleophilic displacement of the mesylate 11 with appropriately substituted aromatic thiols. Most of the target compounds did not show inhibition of either Escherichia coli thymidylate synthase or recombinant human thymidylate synthase at the concentrations tested. However, compounds 2h (2,4‐dichloro), 2j (3,4‐dichloro) and 2m (4‐nitro) did show 25%, 40% and 35% inhibition of human thymidylate synthase at 23 μM, 23 μM and 24 μM, respectively. These observations are in accordance with previous reports, which suggest that strong electron withdrawing substituents on the side chain aromatic ring are conducive to inhibition of thymidylate synthase.
Design and synthesis of a novel intercalating isoxazolyl bis‐lexitropsin conjugate
Authors: Han Xiaochun , Natale Nicholas R.
Published: March 2009

9‐Anthracene nitrile oxide directly generated from 9‐anthracenealdoxime and N‐chlorosuccinamide (NCS), reacts with dimethyl acetylenedicarboxylate (DMAD) and affords the corresponding 3‐(9′‐anthra‐cenyl)‐isoxazole‐4,5‐dicarboxylic acid ester (3) with good yield in a very short period. Double activation reaction between (3) and hydrogenated lexitropsin (5) in a 1:2 molar ratio, produced a bis‐lexitropsin product (6) (major product) and mono‐lexitropsin product (7).
Pyridopyrimidines. X. Synthesis of 3‐Substituted 2‐Thioxo‐5,7‐dimethylpyrido[2,3‐d] pyrimidin‐4(3H)‐ones and their S‐Alkylation Under Phase Transfer Conditions
Authors: Dave Chaitanya G. , Patel Killol J.
Published: March 2009

2‐Thioxo‐5,7‐dimethylpyrido[2,3‐d]pyrimidin‐4(3H)‐ones 3 were synthesized by the cyclocondensation of 2‐amino‐3‐carbethoxy‐4,6‐dimethylpyridine 1 with methyl‐N‐aryldithiocarbamates 2 and compared with the condensation between 1 and aryl isothiocyanates 4. When a comparative study of N vs S alkylation of ambident 2‐thioxo‐5,7‐dimethylpyrido[2,3‐d]pyrimidin‐4(3H)‐ones 3 was carried out under liquid‐liquid and solid‐liquid phase transfer conditions using various alkylating agents 5, the S‐alkylated products 6 were obtained exclusively and selectively.
Synthesis of substituted pyrimido[4,5‐b] and [5,4‐c]‐[1,8]naphthyridines
Authors: Plisson Christophe , Chenault Jacques
Published: March 2009

Ethyl 1‐ethyl‐7‐methyl‐4‐oxo‐1,4‐dihydro[1,8]naphthyridine‐3‐carboxylate (1), precursor of nalidixic acid, has been converted in two steps through ([1,8]naphthyridin‐3‐yl)carbonylguanidine derivatives into substituted pyrimido[4,5‐b] and [5,4‐c][1,8]naphthyridines.
Preparation of N‐(4′,6′‐difluoro‐2′‐hydroxybenzyl)‐monoaza‐15‐crown‐5 and x‐ray crystal structure of potassium thiocyanate complex: A molecular partition wall
Authors: Habata Yoichi , Akabori Sadatoshi
Published: March 2009

Armed monoaza‐15‐crown‐5 having a 4′,6′‐difluoro‐2′‐hydroxybenzyl group as an additional binding site (2) has been prepared by the Mannich reaction of N‐methoxymethylmonoaza‐15‐crown‐5 with 3,5‐difluorophenol. The reactive site on 3,5‐difluorophenol for the Mannich reaction was predicted by an electrostatic potential calculation (density functional calculation, SVWN/DN* method). Ligand 2 is interesting, because it has two possible binding sites (phenolic OH group and fluorine atom) in the side arm. An X‐ray crystal structure of the potassium thiocyanate complex of ligand 2 revealed that the oxygen atom of the phenolic OH group binds to the potassium cation incorporated in the crown ether ring, and two water molecules are enclosed by two armed crown ethers with the crown ethers forming partition walls.
Convenient one pot synthesis of 5‐unsubstituted pyrazolo [3,4‐c]isoquinolines
Authors: Bogza Sergei L. , Malienko Anna A. , Sujkov Sergei Y U. , Perepichka Igor F. , Bogdan Natalya M. , Dulenko Vladimir I. , Kobrakov Konstantin I. , Bryce Martin R.
Published: March 2009

The convenient one pot synthesis of pyrazolo[3,4‐c]isoquinolines 1 from 5‐aminopyrazoles 2 and paraformaldehyde in formic or trifluoroacetic acids is described.
Photoreaction of 1H‐azepine‐2,7‐dione in alkaline solution
Authors: Fukai Yoshihisa , Miyazawa Tomoyuki , Kojoh Mahiro , Takabatake Tohru , Hasegawa Minoru
Published: March 2009

Photolysis of 1H‐azepine‐2,7‐dione 2 proceeded with alkali as in the photoreaction of N‐alkylimide to give 7‐hydroxy‐1H‐azepine‐2‐one 13.
Asymmetric borane reduction of ketones promoted by menthopyrazole‐zncl2 complex
Authors: Kashima Choji , Tsukamoto Yoshihiro , Miwa Yohei , Higashide Kohei
Published: March 2009

The enantioselective reduction of ketones was accomplished by borane in the presence of pyrazole derivatives, particularly 2‐methoxymethyl‐3‐phenyl‐1‐menthopyrazole (8). The catalysis of zinc chloride makes it possible to lower the reaction temperature below 0 °C, and to promote enantioselectivity.
Synthesis of pyrazole‐fused azepino[5,4,3‐cd]indoles
Authors: Safieh Kayed A. Abu , El‐Abadelah Mustafa M. , Zarga Musa H. Abu , Sabri Salim S. , Voelter Wolfgang , MÖssmer Cäcilia M.
Published: March 2009

The synthesis of some new pyrazolo[3′,4′:6,7]azepino[5,4,3‐cd] indoles (10a‐c) was achieved via regios‐elective cyclization of the respective 3‐(4‐acylaminopyrazol‐5‐yl)indoles (9a‐c) under Bischler‐Napieralski reaction conditions. The latter compounds were obtained by acylation of the corresponding 3‐(4‐aminopyra‐zol‐5‐yl)indoles (8a,b) which, in turn, were prepared by reduction of the 3‐(4‐nitropyrazol‐5‐yl)indoles precursors (7a,b). The latter synthons were accessible from the reaction of indolylzinc chlorides (5a,b) with 5‐chloro‐1,3‐dimethyl‐4‐nitropyrazole. Ms and nmr spectral data of 10a‐c are in agreement with the assigned azepino‐indole structure as determined for 10a by X‐ray crystal measurements which demonstrate that the azepine ring is almost completely planar with the indole and pyrazole rings.
Derivatives of pyrido[2,3‐b][1,4]diazepine and of the dipyrido[1,2‐a:2′,3′‐b]imidazole heterocyclic system
Authors: Savelli Francesco , Boido Alessandro , Piacente Sonia
Published: March 2009

With a continuing interest in heteropolycyclic systems which may show biological activities, we studied the reaction of 3‐amino‐2‐(methylamino)pyridine with diethyl 1,3‐acetonedicarboxylate in order to develop pyridodiazepinone derivatives. From the reaction mixture, we separated dipyrido[1,2‐a:2′,3′‐d]imidazole derivatives (3 and 4) besides two isomeric pyrido[2,3‐b][1,4]diazepine derivatives (5 and 6) in which the complex structural differentiation was achieved through nmr experiments and chemical evidence. Several attempts to elaborate isomers 5 and 6 have not yet given significant results.
Cycloaddition reaction of 2‐allenylindoles with diethyl acetylenedicarboxylate under thermal and high pressure conditions
Authors: Ishikura Minoru , Uchiyama Harue , Hino Ayako , Katagiri Nobuya
Published: March 2009

The cycloaddition reaction of 2‐allenylindoles 2 with diethyl acetylenedicarboxylate 6 was undertaken under both thermal and high pressure reaction conditions, leading to carbazole derivatives 5.
Synthesis and anti‐HIV activity of HEPT and S‐DABO‐analogues with 5‐Benzyl and 5‐Phenyl substituents
Authors: Larsen Janus S. , Aal Mohammed Taha Abdel , Pedersen Erik B. , Nielsen Claus
Published: March 2009

6‐Benzyl‐5‐phenyluracil (4) and 5,6‐dibenzyluracil (9) were synthesised from diphenyl acetone (1) and ethyl 3‐oxo‐4‐phenylbutyrate (6), respectively. The uracils were alkylated to afford the 1‐alkoxymethyl‐uracils 5, 10 and 11. Furthermore, S‐alkylated dihydroalkoxybenzyloxopyrimidine (S‐DABO) analogues were prepared by alkylating 5,6‐dibenzyl‐2‐thiouracil (8) on sulfur to yield compounds 12a‐f. All compounds were tested for their inhibition of HIV‐1 reverse transcriptase, and moderate activity was found for 6‐benzyl‐1‐(ethoxymethyl)‐5‐phenyluracil (5).
One ‐ pot synthesis of novel sulfur and selenium heterocycles by directed ortho‐lithiation
Authors: Wright S. W.
Published: March 2009

A procedure for the synthesis of benzo[e][1,3]thiazine‐2,4‐diones from benzamides by directed lithiation and sequential treatment with sulfur and phosgene is reported. Use of thiophosgene afforded 2‐thioxo‐2,3‐dihydro‐benzo[e][1,3] thiazin‐4‐ones. Application of this methodology to benzenesulfonamides afforded the previously unknown 1,1‐dioxo‐1,2‐dihydro‐1,4‐dithia‐2‐aza‐naphthalen‐3‐one ring system with phosgene and the 1,2‐dioxo‐2‐phenyl‐2,3‐dihydrobenzo[e][1,4,2]dithiazine‐3‐one ring system with thiophosgene. Use of selenium in place of sulfur afforded the novel analogous selenium heterocycles, however in the case of benzamides the use of selenium and phosgene afforded benzo[d]isoselenazol‐3‐ones unexpectedly.
Synthesis of new benzylpyridines as potential photochromic compoundsa
Authors: Heynderickx Arnault , Samat André , Guglielmetti Robert
Published: March 2009

Photoinduced proton transfer systems such as 2‐(2′,4′‐dinitrobenzyl)pyridine derivatives have been developed in an attempt to apply the compounds to variable optical transmission materials. However their fatigue resistance property is a limitation for these applications. New benzylpyridines have been synthesized and tested. 2‐(2′,4′‐Diphenylsulfonybenzyl)pyridine was found to be photochromic in the crystalline state and in ethanolic solution (λmax= 485 nm) upon UV flash photolysis.