bluuebunny/crossref_metadata_2025 huggingface dataset:
Convenient substitution of hydroxypyridines with trifluoroacetaldehyde ethyl hemiacetal
Authors: Gong Yuefa , Kato Katsuya , Kimoto Hiroshi
Published: March 2009

Thermal substitution of 4‐hydroxypyridine 1 with trifluoroacetaldehyde ethyl hemiacetal (TFAE) leads to a moderate yield of 3‐(1‐hydroxy‐2,2,2‐trifluoroethyl)‐4‐hydroxypyridine 7 in the presence of a catalytic amount of anhydrous potassium carbonate. Under similar conditions, several α‐trifluoromethyl hydroxy‐pyridinemethanols 8–15 are easily prepared from 2‐ or 3‐hydroxypyridines 2–6.
Synthesis of 5‐[2‐(guanin‐9‐yl)‐ and 5‐[2‐(2‐aminopurin‐9‐yl)ethyl]‐2‐D‐ribo‐(1,2′,3′,4′‐tetrahydroxybutyl)‐1,3‐dioxane
Authors: Kim Dae‐Kee , Kim Young‐Woo , Lee Namkyu
Published: March 2009

Stereoselective synthesis of 5‐[2‐(guanin‐9‐yl)‐ and 5‐[2‐(2‐aminopurin‐9‐yl)ethyl]‐2‐D‐ribo‐(1′,2′,3′,4′‐tetrahydroxybutyl)‐1,3‐dioxane, 2‐5, as potential prodrugs of penciclovir, has been accomplished in six steps from readily available 2,3,4,5‐tetra‐O‐acetyl‐aldehydo‐D‐ribose (6) and the 1,3‐diol7. It has been demonstrated that the use of boron trifluoride diethyl etherate (BF3·Et2O) in dichloromethane along with excess anhydrous copper(II) sulfate was crucial for the efficient formation of cyclic acetal8. In addition, the chromatographic separation ofcisandtransisomers of the cyclic acetal at the bromide stage10was feasible, which was requisite for the successful stereoselective synthesis of the ribosyl derivatives2–5.
Synthesis of 4‐hydroxyquinolin‐2(1H)‐one analogues and 2‐substituted quinolone derivatives
Authors: Jung Jae‐Chul , Jung Young‐Jo , Park Oee‐Sook
Published: March 2009

A versatile synthetic method for preparing 4‐hydroxyquinolone and 2‐substituted quinolone compounds from simple benzoic acid derivatives was demonstrated. The synthetic strategies involve the use of well known ethyl acetoacetate synthesis, malonic ester synthesis and reductive cyclization. The key intermediates were keto esters 4a‐e, which could be transformed to 4‐hydroxyquinolones 5a,b or 2‐substituted quinolone ethyl esters 6a‐c depending on the reaction conditions. 4‐Hydroxyquinolone analogues were prepared and investigated for N‐methyl‐D‐aspartate (NMDA) activity in vitro. Among these derivatives, 6,7‐difluoro‐3‐nitro‐4‐hydroxyquinolin‐2(1H)‐one (9) exhibited moderate activity.
Synthesis of N‐(substituted phenylcarbonylamino)‐4‐ethyl‐1,2,3,6‐tetrahydropyridines as potential nonsteroidal anti‐inflammatory agents
Authors: Yoon Kyoung Jin P. , Kode Bala , Bowen Lynneice , Redda Kinfe K.
Published: March 2009

Fourteen novel N‐(substituted phenylcarbonylamino)‐4‐ethyl‐1,2,3,6‐tetrahydropyridines 9 were synthesized in fair to good yields. 4‐Ethylpyridine 5 reacted with O‐mesitylenesulfonylhydroxylamine (O‐MSH) 4 to furnish N‐amino‐4‐ethylpyridinium mesitylenesulfonate 6. The reaction of 6 with substituted acid chlorides 7 gave the stable crystalline pyridinium ylides 8a‐8n. A sodium borohydride reduction of 8 in absolute ethanol furnished the target compounds N‐(substituted phenylcarbonylamino)‐4‐ethyl‐1,2,3,6‐tetrahydropyridines 9a‐9n.
Synthesis and isolation of iodocarbazoles. Direct iodination of carbazoles by N‐iodosuccinimide and N‐iodosuccinimide‐silica gel system
Authors: Bonesi Sergio M. , Erra‐Balsells Rosa
Published: March 2009

Carbazole (1) undergoes electrophilic aromatic substitution with various iodinating reagents. Although, 3‐iodocarbazole (1b) and 3,6‐diiodocarbazole (1d) obtained by iodination of carbazole were isolated and characterized sometime ago, 1‐iodocarbazole (1a), 1,6‐diiodocarbazole (1c) and 1,3,6‐triiodocarbazole (1e) had never been isolated from the reaction mixture. The preparation and subsequent isolation and characterization of 1a, 1b, 1c, 1d and 1e are reported (mp, tr, Rf, 1H‐nmr, 13C‐nmr and ms). As iodinating reagents, NaIO4/I2 and NaIO4/KI mixtures in (i) ethanol doped with catalytical amount of sulfuric acid and in (ii) acetic acid, and N‐odosuccinimide and N‐iodosuccinimide‐silica gel in dichloromethane and in chloroform have been used and their uses have been compared. The iodination reaction of different carbazole derivatives such as 2‐acetoxycarbazole (2), 3‐bromocarbazole (3) and 3‐nitrocarbazole (4) was also studied and the corresponding iododerivatives, 2a, 2b, 2c, 3a, 3b, 4a and 4b, are described for the first time. Semiempirical PM3 calculations have been performed in order to predict reactivity of carbazole (1), substituted carbazoles (2‐4) and iodocarbazoles (1a‐1e, 2a‐2c, 3a‐3b, 4a and 4b) (Scheme 1). Theoretical and experimental results are discussed briefly.
The synthesis of novel polycyclic heterocyclic ring systems via photocyclization. 23 . Naphtho[2′,1′:4,5]thieno‐[2,3‐c]naphtho[2,1‐f]quinoline
Authors: Luo Jiann‐Kuan , Cabal Maria‐Paz , Federspiel Ronald F. , Castle Raymond N.
Published: March 2009

A previously unknown heterocyclic ring system, naphtho[2′,1′:4,5]thieno[2,3‐c]naphtho[2,1‐f]quinoline (14), was synthesized via oxidative photocyclization of 3‐chloro‐N‐(2‐phenanthryl)naphtho[1,2‐b]‐thiophene‐2‐carboxamide (9). Further elaboration of the lactam 10 yielded the unsubstituted ring system 14. Structural confirmation of compound 14 was accomplished by a total assignment of its 1H and 13C nmr spectra utilizing the concerted two‐dimensional nmr spectroscopic methods.
Synthesis of novel type pyrazolyl and tetrazolyl isoquinolinium zwitterions
Authors: Prauda Ibolya , Reiter Jozsef
Published: March 2009

New type pyrazol‐3‐yl‐isoquinolinium hydrochloride (8a) and tetrazol‐5‐yl‐isoquinolinium (8b) zwitterions were synthesised. Their structures were proved by ir, pmr, cmr, ms spectra as well as X‐ray diffraction analysis of model compounds.
Conformationally restricted tricyclic analogues of lipophilic pyrido[2,3‐d]pyrimidine antifolates
Authors: Gangjee Aleem , Mavandadi Farahnaz , Queener Sherry F.
Published: March 2009

The effect of conformational restriction of the C9‐N10 bridge on inhibitory potency and selectivity of trimetrexate against dihydrofolate reductase, was studied. Specifically three nonclassical tricyclic 1,3‐diamino‐8‐(3′,4′,5′‐trimethoxybenzyl)‐7,9‐dihydro‐pyrrolo[3,4‐c]pyrido[2,3‐d]pyrimidin‐6(5H,8H)‐one (4), 1,3‐diamino‐8‐(3′,4′,5′‐trimethoxybenzyl)‐9‐hydro‐pyrrolo[3,4‐c]pyrido[2,3‐d]pyrimidin‐6‐(8H)‐one (5) and 1,3‐diamino‐(8H)‐(3′,4′,5′‐trimethoxybenzyl)‐7,9‐dihydro‐pyrrolo[3,4‐c]pyrido[2,3‐d]pyrimidine (7) antifolates were synthesized. The tricyclic analogues 4 and 5 were obtained via the regiospecific cyclo‐condensation of the β‐keto ester 17 with 2,4,6‐triaminopyrimidine. The analogue 7 was obtained via reduction of the lactam 4 with borane in tetrahydrofuran. Compounds 4, 5 and 7 were evaluated as inhibitors of dihydrofolate reductase from Pneumocystis carinii, Toxoplasma gondii and rat liver. All three compounds were more selective than trimetrexate against Pneumocystis carinii dihydrofolate reductase and significantly more selective than trimetrexate against Toxoplasma gondii dihydrofolate reductase compared with rat liver dihydrofolate reductase.
Synthesis of 5,6‐dihydrothieno(and furo)pyrimidines bearing an active methine group at the 4‐position
Authors: Maruoka Hiroshi , Yamagata Kenji , Yamazaki Motoyoshi
Published: March 2009

The reactions of 2‐benzamido‐4,5‐dihydro‐3‐thiophene(and ‐3‐furan)carbonitriles (1a‐c and 4a‐c) with ethyl acetoacetate in the presence of tin(IV) chloride and triethylamine provided the corresponding ethyl 2‐(5,6‐dihydro‐2‐phenylthieno(and furo)[2,3‐d]pyrimidin‐4‐yl)‐3‐oxobutanoates (2a‐c and 9a‐c). Similarly, compounds 1a‐c and 4a‐c reacted with dialkyl malonates to give the corresponding dialkyl(5,6‐dihydro‐2‐phenylthieno(and furo)[2,3‐d]pyrimidin‐4‐yl)propanedioates (5a‐c, 6a‐c, 10a‐c and 11a‐c).
The photochemistry of 6‐phenanthridinecarbonitrile II. The physical and photophysical properties
Authors: Vittimberga Bruno M. , Sears Donald
Published: March 2009

The physical and photophysical properties of 6‐phenanthridinecarbonitrile (1) have been examined. We previously reported that when 1 is irradiated in aqueous 2‐propanol, three products are formed [3]. These include dimethyl‐6‐phenanthridinylcarbinol (2), phenanthridine (3) and 6,6′‐biphenanthridine (4). Phenanthridinyl radical is formed in neutral media by hydrogen atom abstraction from an alcohol molecule by an excited state of 1 in a monophotonic process. The presents of acid effectively quenches all photochemical behavior. These products may all be explained assuming in‐cage and out‐of‐cage reactions. The free spin value, ge, was determined at 125 K and found to be 2.0043 which is close to the theoretical value for that of a free electron. The total emission spectrum of 1 at 77 K shows a fluorescence maximum at 378 nm and a much weaker phosphorescence maximum at 502 nm which represented less than 3% of the total emission. When benzophenone is added to the reaction mixture, the triplet state of 1 is populated, but photosensitized product formation does not occur. The result supports a singlet reactive state. When cis/trans‐piperylene is added to the reaction mixtures, it quenches the fluorescence of 1. The fluorescence quantum yield (Φf) was found to be 0.227 in neat 2‐propanol. The addition of water causes an increase in Φf and a decrease in the Pka of the medium. The excited state lifetime (τ) was determined in neat 2‐propanol, using oxygen quenching, and found to be 3.4 ns. This number increased with increasing water concentration. The photoreactive state of 1 appears to be its π,π* singlet state making its behavior more like that of the corresponding hydrocarbon parent.
Synthesis and properties of calixarene analogs incorporating a thiophene unit in the macrocyclic ring
Authors: Ito Kazuaki , Ohba Yoshihiro , Tamura Takafumi , Ogata Tomoaki , Watanabe Hajime , Suzuki Yasumitsu , Hara Takayuki , Morisawa Yukou , Sone Tyo
Published: March 2009

Calixarene analogs containing a thiophene unit in the macrocyclic ring were prepared by a stepwise method. The macrocycles adopt a cone‐like form as the preferred conformation in solution. The induced chemical shift change, nOe experiment, and 1H relaxation time (T1) measurement supported the fact that the macrocycle forms a complex with the N‐methylpyridinium salt. In contrast, O‐tetramethylated macrocycles and linear phenol‐formaldehyde tetramer, could not efficiently include the N‐methylpyridinium salt.
Reactions of 4‐chloro‐5h‐1,2,3‐dithiazole‐5‐thione with α,β‐unsaturated β‐amino esters: Formation of 2‐[2‐(1‐alkenylsulfanyl‐1‐alkoxycarbonyl‐2‐amino)‐1,2‐dicyano‐vinylsulfanyl]‐3‐amino‐2‐alkenoic alkyl esters
Authors: Chang Yong‐Goo , Kim Kyongtae , Ja Park Yung
Published: March 2009

Treatment of 4‐chloro‐5H‐1,2,3‐dithiazole‐5‐thione with alkyl 3‐alkyl (or aryl)‐3‐amino‐2‐propenoates in the presence of pyridine (2 equivalents) in dichloromethane at reflux gave 2‐[2‐(1‐alkenylsulfanyl‐1‐alkoxy‐carbonyl‐2‐amino)‐1,2‐dicyanovinylsulfanyl]‐4 and‐1,2‐dicyanovinyldisulfanyl]‐3‐amino‐2‐alkenoic alkyl esters 7 in 16 to 60% and 8 to 48% yields, respectively.
Synthesis of 4‐pyrone‐containing polyethers
Authors: Löwe Werner , Brätter Stefanie A. , Dietrich Christoph
Published: March 2009

The preparation of novel crown type compounds 6 and 8 with a 4‐pyrone unit is described.
Derivatives of 2,3‐dihydroimidazo[1,5,4‐ef][1,2,5]‐benzothiadiazepin‐6(4h,7h)‐thione 1,1‐dioxide, a new heterocyclic system related to tibo
Authors: Costi Roberta , Di Santo Roberto , Artico Marino , Massa Silvio
Published: March 2009

The synthesis of derivatives of 2,3‐dihydroimidazo[1,5,4‐ef][1,2,5]benzothiadiazepin‐6(4H,7H)‐thione 1,1‐dioxide is reported starting from N‐substituted ethyl 2‐(5‐chloro‐2‐nitrobenzenesulfonamido)‐2‐alkyl‐acetates. Fundamental steps of the synthetic pathway were: i) intramolecular cyclization of N‐substituted 2‐(2‐amino‐5‐chlorobenzenesulfonamido)‐2‐alkylacetic acids in the presence of N‐(3‐dimethyl‐aminopropyl)‐N′‐ethyl carbodiimide hydrochloride‐N,N‐dimethylaminopyridine complex; ii) building of imidazole ring from 2‐alkyl‐8‐chloro‐2,3‐dihydro‐3‐methyl‐1,2,5‐benzothiadiazepin‐4(5H)‐one 1,1‐dioxide to achieve 2‐alkyl‐9‐chloro‐2,3‐dihydro‐3‐methylimidazo[1,5,4‐ef][1,2,5]benzothiadiazepin‐6(4H,7H)‐one 1,1‐dioxide; iii) preparation of thiocarbonyl derivative by treatment with Lawesson's reagent. Introduction of a 3‐methyl‐2‐butenyl chain at position 2 of above imidazobenzothiadiazepinone required protection at the 7 position with thermally removable tert‐butoxycarbonyl moiety, due to the fact that alkylation of unprotected structure proved to be regioselective for the 7 position.
An improved procedure for the deamination of symmetrical 3,5‐disubstituted 4‐amino‐1,2,4‐triazoles
Authors: Bentiss Fouad , Lagrenee Michel , Vezin Hervéa , Bouanis Marya , Mernari Bouchaib
Published: March 2009

A number of symmetrical 3,5‐disubstituted‐4H‐1,2,4‐triazoles have been synthesized in good yields by deamination of the corresponding 4‐amino‐1,2,4‐triazoles via reductive diazotation of these amino compounds in the presence of hypophosphorous acid. Analytical, spectral data and theoretical calculations confirmed the structures of the new triazole derivatives.
Aminolysis of methoxy groups in pyrimidine derivatives. Activation by 5‐nitroso
Authors: Melguizo Group M. , Marchal A. , Nogueras M. , Sánchez A. , Low J. N.
Published: March 2009

The nucleophilic substitution of 2‐mefhoxy groups in pyrimidine derivatives was strongly activated by introduction of a 5‐nitroso group on to the pyrimidine ring. The aminolysis of several 2‐methoxy‐5‐nitrosopyrimidine derivatives was performed at room temperature in hydroxylic as well as in non‐hydroxylic media with different primary amines in short time and good yields. The aminolysed substrates include 6‐[(per‐O‐acetyl)glycosyl]aminopyrimidines which afforded the corresponding 2‐aminopyrimidines without harming the acetyl protecting groups of the sugar moiety.
Studies with 1‐functionally substituted alkyl azoles: Novel synthesis of functionally substituted azolylbenzimidazoles and functionally substituted azolyl‐1,2,4‐triazoles
Authors: Abdel‐Megid Mohamed , Elnagdi Mohamed H. , Negm Abdalla M.
Published: March 2009

ω‐Azolylacetophenones 1 and 2 react with dimethylformamide dimethylacetal to yield enaminones 7,8 that were converted into azolylazoles via reaction with hydrazine and with hydroxylamine. Compounds 1,2 also coupled with aromatic diazonium salts to yield arylhydrazones and reacted with nitrous acid to yield corresponding oximes.
Studies on pyrrolidinones: Some attempts to improve the synthesis of methyln‐(3,4,4′,5‐tetramethoxybenzhydryl)pyroglutamate (hei 81) by usingn‐acyl iminium salts methodologies
Authors: Bourry Anne , Pitard Franck , Rigo Benoît , Sanz Géarard , Camus Fabrice , Norberg Bernadette , Durant Françlois , Couturier Daniel
Published: March 2009

Some ways to use theN‐acyl iminium salt methodologies to synthesize a new inhibitor of tubulin polymerization, methylN‐(3,4,4′,5‐tetramethoxybenzhydryl)pyroglutamate (HEI 81) were studied. The most interesting reactions utilize a new pyroglutamic lactone (3‐(3,4,5‐trimethoxyphenyl)dihydropy‐rrolo[1,2‐c]oxazole‐1,5‐dione).
The synthesis of n‐substituted isothiazol‐3(2h)‐ones from nsubstituted 3‐benzoylpropionamides
Authors: Hamilakis Stylianos , Kontonassios Demetrios , Tsolomitis Athanase
Published: March 2009

N‐Substituted isothiazol‐3(2H)‐ones can be easily prepared from N‐substituted 3‐benzoylpropi‐onamides in two experimentally simple steps, in satisfactory overall yields. Reaction of the amides with excess thionyl chloride results in the formation of N‐substituted 5‐benzoylisothiazol‐3(2H)‐ones, which are readily debenzoylated with alkali to the corresponding N‐substituted isothiazol‐3(2H)‐ones. This method has now been successfully applied to the synthesis of isothiazolones N‐substituted with a bulky alkyl group, such as the tert‐butyl group, and with a phenyl group bearing either a strong electron‐withdrawing substituent, such as the 3‐nitrophenyl and 4‐nitrophenyl group, or an electron‐releasing substituent, such as the 4‐methylphenyl and 4‐methoxyphenyl group.
Synthesis of 2‐substituted‐3‐nitroimidazo[1,2‐b]pyridazines as potential biologically active agents
Authors: Terme Thierry , Maldonado Joséa , Crozet Michel P. , Vanelle Patrice , Galtier Christophe , Gueiffier Alain
Published: March 2009

A new heterocyclic reductive alkylating agent, 6‐chloro‐2‐chloromethyl‐3‐nitroimidazo[1,2‐b]pyridazine, was synthesized for the first time. It was shown to react under phase‐transfer catalysis conditions with 2‐nitropropane anion by an SRN1 mechanism to give excellent yield of isopropylidene derivative formed from a base‐promoted nitrous acid elimination of C‐alkylation product. Extension of this SRN1 reaction to various nitronate anions led to a new class of 3‐nitroimidazo[1,2‐b]pyridazine derivatives bearing a trisub‐stituted double bond at the 2‐position.
Synthesis and spectroscopic studies of optically active n‐acetyl butenoates and n‐acetyl‐2‐alkyl‐pyrrolin‐4‐ones
Authors: Gavrielatos Efstathios , Athanasellis Giorgos , Igglessi‐Markopoulou Olga
Published: March 2009

The synthesis of a series of optically active N‐acetyl butenoates 3–5 is described using a facile methodology. These butenoates undergo cyclization to the corresponding N‐acetyl‐2‐alkyl‐pyrrolin‐4‐ones 6,7 retaining their stereochemical integrity. The structure of the newly synthesized compounds has been elucidated through 1H‐13C NMR, IR spectroscopy and their enantiomeric excesses have been measured by chiral HPLC analysis.
Synthesis and properties of novel macrocyclic compounds bearing thiourea moieties by use of chemical feature of hypervalent sulfur
Authors: Matsumura Noboru , Konishi Tsunao , Hayashi Hirokazu , Mizuno Kazuhiko , Yasui Masanori , Iwasaki Fujiko
Published: March 2009

Macrocyclic compounds 5a‐i bearing two tetraazathiapentalene frameworks were synthesized by the reaction of 10‐S‐3 tetraazathiapentalene derivatives 3a‐f with compounds having various diisothiocyanate functions 4a‐e. The reduction of the macrocyclic compounds with NaBH4 afforded the ring‐opened macrocyclic compounds 11a‐b and 11e‐h by elimination of the hypervalent sulfur. The structures of these compounds were established by their spectral data and also by the X‐ray crystallographic analysis of lla. The other ring‐opened macrocyclic compounds 14a and 14e‐h that bear four thiourea groups were synthesized by alkaline hydrolysis of 5a and 5e‐h in that elimination of the C=SIV moiety in the tetraazathiapentalene rings occurred.
Syntheses of 7‐phenyl‐5h‐thiazolo[5,4‐e]pyrrolo[1,2‐a][1,4]diazepin‐10(9h)one,7‐phenyl‐5h‐thiazolo[5,4‐e][1,2,3,4]tetrazolo[5,1‐c]‐pyrrolo[1,2‐a][1,4]diazepine and 7‐phenyl‐5h‐thiazolo[5,4‐e]‐[1,3,4] triazolo [5,1‐c]pyrrolo [1,2‐a] [1,4] diazepines
Authors: Shafiee A. , Shekarchi M.
Published: March 2009

Fused tricyclic 7‐phenyl‐5H‐thizolo[5,4‐e]pyrrolo[1,2‐a][1,4]diazepin‐10(9H)one (10) was prepared by thermolysis of 2‐phenyl‐4‐(1‐pyrrolylmethyl)thiazole‐5‐carbonyl azide (9) in acetic acid. In addition, starting from 10, 7‐phenyl‐5H‐thiazolo [5,4‐e][1,3,4]triazolo[5,1‐c]pyrrolo[1,2‐a][1,4]diazepines (13) and 7‐phenyl‐5H‐thiazolo[5,4‐e] [1,2,3,4]tetrazolo[5,1‐c]pyrrolo[ 1,2‐a] [1,4]diazepine (14) were synthesized.
Synthesis of 3,4‐dihydro‐2h‐thiopyrans by the reaction of 4,5‐dihydrothiophenium‐1‐bis[ethoxy(and methoxy)carbonyl]methylides with sodium iodide
Authors: Maruoka Hiroshi , Yamagata Kenji , Yamazaki Motoyoshi
Published: March 2009

Sulfonium ylides 1a‐h reacted with sodium iodide to afford the corresponding thiopyrans 2a‐h. On the other hand, compounds 1a‐d were treated with thionyl chloride to give the ring opening products 3a‐d. The reaction of compounds 3a‐d with sodium iodide and triethylamine provided the corresponding thiopyrans 2a‐d.
Conversion of (±)‐3‐ethyl‐3‐methyl phthalides to 3,3‐dimethyl‐3,4‐dihydroisocoumarins. Synthesis of 3‐methylmellein
Authors: Bhide B. H. , Kalaria A. J. , Panchal B. M.
Published: March 2009

o‐Lithio yV‐methyl benzamides (1a‐f) upon alkylation with ethyl methyl ketone gave (±)‐3‐ethyl‐3‐methyl phthalides (2a‐f), which upon treatment with concentrated H2SO4 or anhydrous A1C13 furnished corresponding 3,3‐dimethyl‐3,4‐dihydroisocoumarins (3a‐f) and 3‐methyl mellein (3g).
2,6‐Diaryl‐4,4‐disubstituted‐4H‐thiopyran: Source for spiro heterocycles
Authors: Padmavathi Venkatapuram , Balaiah Akula , Reddy Dandu Bhaskar
Published: March 2009

The 1,5‐diaryl‐3,3‐disubstituted‐1,5‐pentanedione on reaction with ammonium acetate, phosphorus pentoxide and phosphorus pentasulfide gave respective 1,4‐dihydropyridine, 4H‐pyran and 4H‐thiopyran. Novel spiro heterocycles have been obtained by the cyclocondensation of 4H‐thiopyran with hydrazine, hydroxylamine, urea and thiourea.
Synthesis of 1‐(2‐benzofurancarbonyl)azulenes using 1‐(bromoacetyl)azulenes as new building blocks
Authors: Yamashiro Satoko , Imafuku Kimiaki
Published: March 2009

1‐Acetylazulene (1) was treated with trimethylphenylammonium tribromide in refluxing chloroform to afford 1‐acetyl‐3‐bromoazulene (3) and 3‐bromo‐1‐(bromoacetyl)azulene (4). In a similar manner, 3‐methyl‐, 3‐ethyl‐, 3‐propyl‐, and 3‐methoxycarbonyl‐substituted 1‐acetylazulenes 2a‐d gave the corresponding 3‐substituted 1‐(bromoacetyl)azulenes 5a‐d as major products and 1‐(dibromoacetyl)azulenes 6a‐d as minor ones. The 1‐(bromoacetyl)azulenes 5a‐d are useful as new building blocks. Compounds 5a‐d reacted with salicylaldehydes 9a‐g to yield twenty‐eight cyclized products, 1‐(2‐benzofurancarbonyl)azu‐lenes 11aa‐dg, via 1‐phenoxyacetylazulenes 10aa‐dg.
Diazine‐derived guanidines, isothioureas, and isoureas: Synthesis and attempts of configurational assignment
Authors: Heinisch Gottfried , Matuszczak Barbara , Rakowitz Dietmar , Mereiter Kurt
Published: March 2009

The utility of diazinyl substituted carbodiimides (1a‐c) for the synthesis of novel guanidines (2), isothioureas (3), and isoureas (4) is shown. Attempts to determine the stereochemistry of the target compounds using NOE difference spectroscopy or X‐ray analysis, respectively, are described.
Synthesis of optically active af‐(1‐Ethyl‐3‐methylhexahydro‐1,3‐diazin‐5‐yl)‐ and N‐(1‐Ethyl‐5‐methyloctahydro‐1,5‐diazocin‐3‐yl)pyridine‐3‐carboxamides
Authors: Hirokawa Yoshimi , Yamazaki Hiroshi , Kato Shiro
Published: March 2009

As part of the structure‐activity relationship of the dopamine D2 and serotonin 5‐HT3 receptors antagonist 1, which is a clinical candidate with a broad antiemetic activity, the synthesis and dopamine D2 and serotonin 5‐HT3 receptors binding affinity of (R)‐5‐bromo‐N‐(1‐ethyl‐3‐methylhexahydro‐1,3‐diazin‐5‐yl)‐ and (R)‐5‐bromo‐N‐(1‐ethyl‐5‐methyloctahydro‐1,5‐diazocin‐3‐yl)‐2‐methoxy‐6‐methylaminopyridine‐3‐carboxam‐ides (2 and 3) are described. Treatment of 1‐ethyl‐2‐(p‐toluenesulfonyl)amino‐3‐methylaminopropane dihy‐drochloride (4a) with paraformaldehyde and successive deprotection gave the 5‐aminohexahydro‐1,3‐diazine 6 in excellent yield. 3‐Amino‐1‐ethyl‐5‐methyloctahydro‐1,5‐diazocine (15) was prepared from 2‐(benzyloxycarbonyl)amino‐3‐[[N‐(tert‐butoxycarbonyl)‐N‐methyl]amino]‐1‐ethylaminopropane (9) through the intramolecular amidation of (R)‐3‐[N‐[(2‐benzyloxycarbonylamino‐3‐methylamino)propyl]‐N‐ethyl]aminopropionic acid trifluoroacetate (12), followed by lithium aluminum hydride reduction of the resulting 6‐oxo‐1‐ethyl‐5‐methyloctahydrodiazocine (13) in 41% yield. Reaction of the amines 6 and 15 with 5‐bromo‐2‐methoxy‐6‐methylaminopyridine‐3‐carboxylic acid furnished the desired 2 and 3, which showed much less potent affinity for dopamine D2 receptors than 1.
Reactivity of 2‐substituted imidazo[1,2‐b]pyridazines: Preparation of 3‐nitro, nitroso and chloro derivatives
Authors: Hervet Maud , Galtier Christophe , Enguehard CÉcile , Gueiffier Alain , Debouzy Jean‐Claude
Published: March 2009

The synthesis of 2‐substitutedimidazo[1,2‐b]pyridazines and their reactivity towards electrophilic substitutions are reported. The nitration was shown to be very dependent on the nature of the 2 substituent. Nitrosation using sodium nitrite in acetic acid media as a general method failed in all cases whereas chlorination was observed in warm hydrochloric acid. In order to ascertain the structure of some chloro derivatives, chlorination using N‐chlorosuccinimide was also reported. Depending of the nature of the substituent, the reaction occurred at the C‐3 imidazolic position and/or at the substituent on position 2. The 3‐nitroso‐2‐phenyl derivative was finally obtained using an alternative synthetic pathway by direct condensation of 3‐amino‐6‐chloropyridazine to ω‐chloro‐ω‐nitrosoacetophenone. The structural determinations were ascertained using high field lH and 13C‐NMR.
Synthesis of vinca alakaloids and realated compounds 98. Oxidation with dimethyldioxirane of compounds containing the aspidospermane and quebrachamine ring system. A simple synthesis of (7S,20S)‐(+)‐rhazidigenine and (2R,7S,20S)‐(+)‐rhazidine
Authors: Éles János , Kalaus György , SzabÓ Lajos , LÉvai Albert , Greiner IstvÁn , KajtÁr‐Peredy MÁria , SzabÓ PÁl , SzÁntay Csaba
Published: March 2009

The oxidation of (‐)‐tabersonine (1) with dimethyldioxirane (DMD) in neutral and acidic medium gave 16‐hydroxytabersonine‐N‐oxide (3) and the didehydrovincamine isomers 4 and 5, respectively. (+)‐14,15‐Didehydro‐quebrachamine (7) furnished the hydroxyindolenine 9, and the pentacyclic derivative 11. (+)‐Quebrachamine (8) and DMD in neutral medium gave (7S,20S)‐(+)‐rhazidigenine (12) which was converted to (2R,7S,20S)‐(+)‐rhazidine (13b) with hydrochloric acid.
Preparation of a series of benzothieno[3,2‐b]pyridine‐3‐carbonitriles and benzofuro[3,2‐b]pyridine‐3‐carbonitriles
Authors: Boschelli Diane H. , Ye Fei
Published: March 2009

New and shorter routes to the benzothieno[3,2‐b]pyridine‐3‐carbonitrile and benzofuro[3,2‐b]pyridine‐3‐carbonitrile ring systems are reported. These heterocycles may function as new templates for kinase inhibitors.
Reactivity studies on 4‐aminopyrones: Access to benzimidazole and benzimidazolone derivatives
Authors: Amari Mohamed , Fodili Mokhtar , Nedjar‐Kolli Bellara , Hoffmann AlgÉrie Pascal , PÉriÉ Jacques
Published: March 2009

Reaction of pyrone 1a or tetronic acid 1b with o‐phenylenediamine derivatives gave enaminone compounds 2. When reacting with different electrophiles, these intermediates allowed versatile access to different heterocyclic structures: when DMA derivatives or triphosgene was used, cyclization occurred through nitrogen, leading to benzimidazoles 3 and benzimidazolones 4, respectively, while reaction with benzaldehyde yielded benzodiazepines 5.
Dimethyldioxirane oxidation of the epoxides of (Z)‐3‐arylidene‐1‐thioflavanones
Authors: LÉvai Albert , Patonay TamÁs , TÓth GÁbor , KovÁcs JÓzsef , Jekö JÓzsef
Published: March 2009

Sulfur atom of the trans, cis‐ and trans, trans‐epoxides 1 of (Z)‐3‐arylidene‐1‐thioflavanones have been oxidized with dimethyldioxirane to afford the appropriate sulfoxides 2 and sulfones 3 depending on the amount of oxidant used.
Elaboration of 1,8‐naphthyridine‐2,7‐dicarboxaldehyde into novel 2,7‐dimethylimine derivatives
Authors: Vu Choua , Walker Deedee , Wells Jason , Fox Stephen
Published: March 2009

The known 1,8‐naphthyridine‐2,7‐dicarboxaldehyde was prepared by SeO2 oxidation of 2,7‐dimethyl‐1,8‐naphthyridine. The dimethylated naphthyridine molecule was assembled from an adaptation of the Skraup synthesis using 2‐amino‐6‐methylpyridine and crotonaldehyde to afford a reproducible 37% yield, and constitute a significant advance over the literature of this reaction. The condensation of 1,8‐naph‐thyridine‐2,7‐dicarboxaldehyde with various primary amines (R = ‐C6H11, ‐CH2C6H5, ‐C(CH3)3, ‐C10H15, and CH2CH2SCH2CH3) in alcohol affords diimines 1(a‐e). The inherent crystallinity of 1(a‐e) affords pure compounds in reasonable to excellent yields (ca. 70%) after evaporation of solvent and recrystallization. The anticipated spectroscopic features of (N=C‐H) 1H nmr shift and v(C=N) in the ir spectrum appear around 8.50 δ and 1640 cm−1, respectively, for the series 1(a‐e). These novel naph‐thyridines typically display the signature 1H nmr doublets at ca. 8.15‐8.30 δ ascribed to the 3 and 4 naphthyridine protons, consistent with a mirror plane (through the quaternary carbons) perpendicular to the naphthyridine plane, and syn, syn relationships of the naphthyridine moiety with each imine nitrogen lone pair. Complexation studies of 1(a‐e) with transition metals of biological relevance such as copper(I) and copper(II) will be reported elsewhere.
Synthesis and biological effects of new derivatives of benzotriazole as antimicrobial and antifungal agents
Authors: Al‐Omran Fatima , El‐Khair Adel Abou , Mohareb Rafat M.
Published: March 2009

Derivatives of 2‐aminothiophene‐3‐carbonitrile, 2‐thioxopyridine‐3‐carbonitrile, 1,8‐naphthyridine‐2‐one, thieno[2,3‐b]pyridine‐5‐carbonitrile and thieno[2,3‐d]pyrimidine incorporating with a 1H‐benzo‐triazole moiety or 1,3,4‐thiadiazole derivatives incorporating with a benzotriazol‐1‐ylmethyl group have been synthesized and tested for antimicrobial and antifungal activities. The structures of the newly synthesized compounds have been established on the basis of their analytical and spectral data.
New 1,2,3‐triazolo[4,5‐e]1,2,4‐triazolo[4,3‐c]pyrimidine derivatives II
Authors: Biagi Giuliana , Giorgi Irene , Livi Oreste , Pacchini Federica , Scartoni Valerio
Published: March 2009

The 7‐chloro‐3‐(2‐chlorobenzyl)‐ and 7‐chloro‐3‐(2‐fluorobenzyl)‐1,2,3‐triazolo[4,5‐d]pyrimidines (1 and 4), by nucleophilic replacement with some hydrazides, gave the corresponding 7‐hydrazidoderivatives (2a‐e and 5a‐e). These, by heating in Dowtherm, underwent an intramolecular cyclization to form the new tricyclic 7‐substituted‐3‐(2‐chlorobenzyl)‐ and 3‐(2‐fluorobenzyl)‐1,2,3‐triazolo[4,5‐e]1,2,4‐triazolo[4,3‐c]pyrimidines (3a‐d and 6a‐d). The 7‐hydrazino‐3‐(2‐chlorobenzyl)‐ and 7‐hydrazino‐3‐(2‐fluorobenzyl)‐triazolo‐pyrimidines (9a and 9b) were also prepared via the corresponding mercapto (7a and 7b) and thiomethyl (8a and 8b) derivatives.
New 1,2,3‐triazolo[4,5‐d]1,2,4‐triazolo[3,4‐b]pyridazine derivatives II
Authors: Biagi Giuliana , Ciambrone Fabio , Giorgi Irene , Livi Oreste , Scartoni Valerio , Barili Pier Luigi
Published: March 2009

New tricyclic 1,2,3‐triazolo‐1,2,4‐triazolo‐pyridazine derivatives, bearing a methyl substituent on the 1,2,3‐triazole ring, were prepared as potential biological agents. N‐Methylation of dimethyl 1,2,3‐triazole‐4,5‐dicarboxylate allowed synthesis of the isomeric 1‐methyl‐4,7‐dihydroxy and 2‐methyl‐4,7‐dihydroxy triazolo‐pyridazines 4a and 4b which, by a chlorination reaction, gave the corresponding 1‐methyl‐4‐chloro‐(6a), 1‐methyl‐7‐chloro‐ (6b) and 2‐methyl‐4‐chloro‐ (9) substituted 1,2,3‐triazolo‐pyridazines. The nucle‐ophilic substitution with hydrazine hydrate and the suitable cyclization to form the 1,2,4‐triazole ring, provided the expected tricyclic isomeric derivatives 8a, 8b and 11 respectively. The p‐methoxybenzyl substituent, introduced as a leaving group to obtain either v‐triazolo‐pyridazine or v‐triazolo‐s‐triazolo‐pyri‐dazine derivatives unsubstituted on the 1,2,3‐triazole ring, appeared inadequate. Some compounds underwent binding assays toward the adenosine A1and A2A receptors.
Stereoselective dimerization of benzylic amines derived from indoline
Authors: Nowak Ireneusz , George Clifford
Published: March 2009

Treatment of benzylic amines derived from 2‐(acyloxymethyl)‐5‐nitroindolines with sodium hexamethyl‐disilazide leads to dimeric products resulting from deprotonation in the benzylic position, oxidation of the resulting carbanion to radical by the nitroarene moiety of another molecule, and stereoselective radical recombination. Only those two of six possible diastereoisomers are formed in which the recombination takes place from the less hindered face in the more stable conformation of the presumably near‐planar radical.
Asymmetric reaction of diethylzinc with aldehydes catalyzed byl‐menthopyrazole derivatives
Authors: Kashima Choji , Higashide Kohei , Miwa Yohei , Tsukamoto Yoshihiro
Published: March 2009

N‐Hydroxyalkyl‐1‐menthopyrazoles acted as a chiral catalyst for the diethylzinc (1) addition to aromatic aldehydes, and 1‐aryl‐1‐propanols were afforded enantioselectively. These reactions were carried out optimally in toluene at 40 °C in the presence of 30 mol% of (2′S)‐2‐(2‐phenyl‐2‐hydroxyethyl)‐3‐phenyl‐1‐men‐thopyrazole ((S)‐16d) to afford optically active 1‐aryl‐1‐propanols up to 70% ee (S).
Synthesis and isolation of iodocarbazoles. Direct iodination reaction of N‐substituted carbazoles
Authors: Monge María E. , Bonesi Sergio M. , Erra‐Balsells Rosa
Published: March 2009

Iododerivatives of N‐methylcarbazole (1), N‐phenylcarbazole (2), N‐benzylcarbazole (3), 2‐methoxy‐N‐methylcarbazole (4) and 3‐acetamido‐N‐ethylcarbazole (5) are synthesised. N‐Iodosuccinimide (NIS) in tetrahydrofurane/H2SO4 (catalyst), a mixture of KIO3 ‐ KI ‐ H2SO4 (catalyst) in ethanol and a mixture of KIO3 ‐ KI in glacial AcOH as iodinating agents have been used and their uses have been compared. The preparation, isolation and characterization of compounds 1a, 1b, 1c, 1d, 2a, 2b, 3a, 3b, 4a, 4b, 4c and 5a are reported (mp, tR, Rf, 1H‐nmr, 13C‐nmr, IR and ms). All of them are described for the first time except 3,6‐diiodo‐N‐phenyl‐carbazole (2b). Semiempirical PM3 calculations have been performed to predict reactivity of N‐substituted carbazoles and their iododerivatives. Theoretical and experimental results are discussed briefly.
Synthesis and characterization of stable betainic pyrimidinaminides
Authors: Schmidt Andreas
Published: March 2009

Depending on electronically or kinetically stabilizing effects determined by the substitution pattern or the reaction conditions, 6‐amino substituted (5‐chloropyrimidine‐2,4‐diyl)bis(hetarenium) salts or 5‐chloro‐2,6‐bis‐(pyridinio)‐pyrimidin‐4‐aminides are formed on nucleophilic substitution of 4‐(dimethylamino)pyridine, 4‐(pyrrolidin‐1‐yl)pyridine, or 1‐methylimidazole on 4‐amino substituted 2,5,6‐trichloropyrimidines.
Novel fluorescent quater‐ and quinquifurans: Syntheses and photophysical properties
Authors: Kauffman Joel M. , Moyna Guillermo
Published: March 2009

In the quest for fast fluors for use in waveshifting polystyrene fibers, symmetrical oligofurans were investigated. Furan moieties were coupled by means of the Ullmann Reaction or by palladium‐catalyzed unsym‐metrical coupling; the latter gave higher yields. While the benzoxazole‐terminated quater‐ and quinquifurans we prepared were both stable and fast, exhibiting a green fluorescence and decay times of about 2.4 nsec, they were inferior to other types of fluors in solubility and emission intensity when incorporated into polystyrene.
Synthesis of 3‐Ω‐aminohydantoins
Authors: Ryczek Józef
Published: March 2009

Several 3‐Ω‐amino monosubstituted hydantoins have been obtained in the reaction of isocyanate of glycine ethyl ester with the appropriate aliphatic or aromatic diamine. It was found, that the 3‐(aminoaryl) monosubstituted hydantoins may be diazotized and their diazonium salts may be coupled and hydrolysed without changes in the hydantoin ring.
Reactivity of 2‐methylene‐1,3‐dicarbonyl compounds. 1,3‐dipolar cycloaddition reaction with nitrile oxide
Authors: Yamauchi Masashige
Published: March 2009

The reaction of 2‐methylene‐1,3‐dicarbonyl compounds 1 and nitrile oxides, which were prepared from hydroxymoyl chlorides 2 with triethylamine, gave 5,5‐disubstituted 2‐isoxazolines 3 regioselectively.
Synthesis and properties of isoviagra. A 2‐methyl‐2H‐pyrazolo[4,3‐d]pyrirnidin‐7‐one isomer of viagra®
Authors: El‐Abadelah Mustafa M. , Sabri Salim S. , Khanfar Monther A. , Yasin Hani A. , Voelter Wolfgang
Published: March 2009

The synthesis and spectral properties (ir, ms, nmr) of a substituted 2‐methyl‐2H‐pyrazolo[4,3‐d]‐pyrimidin‐7‐one (3), an isomer of Viagra®, are described. The key synthon, 4‐amino‐1‐methyl‐5‐propyl‐3‐pyrazolecarboxamide (7), is prepared via the reaction of ethyl 2,4‐dioxoheptanoate with methylhydrazine, followed by cyclization, nitration, amidation, and nitro group reduction. Interaction of 7 with 2‐ethoxyben‐zoyl chloride yielded the respective bis‐amide (8) which was cyclized in polyphosphoric acid to the corresponding pyrazolo[4,3‐d]pyrimidin‐7‐one derivative 9. Chlorosulfonylation of 9, and subsequent treatment with 1‐methylpiperazine furnished iso Viagra (3).
A new convenient method for the synthesis of 2H‐1,4‐benzoxazine derivatives from nitroketones via intramolecular reductive cyclization
Authors: Ju Joung Meyoung , Ahn Jin Hee , Kim Hoe Moon , Yoon Nung Min , Kim Kee Won , Kang Jae Hoon , Lee Seok Joon
Published: March 2009

Dedicated to Professor Herbert C. Brown on the occasion of his 90th birthday.

Potentially bioactive 2H‐1,4‐benzoxazine derivatives could be conveniently prepared in one step from the corresponding nitroketones using 10% palladium on carbon with triethylamine in the presence of hydrogen (Pd/C‐TEA‐H2) system. Several other tertiary amines such as nicotine, pyridine, and quinoline also could be used, but TEA gave the best results.
N‐bromosuccinimide catalyzed condensations of indoles with carbonyl compounds under solvent‐free conditions
Authors: Koshima Hideko , Matsusaka Wataru
Published: March 2009

NBS was found to be an efficient catalyst for condensations of indoles with aldehydes or ketones in the absence of solvent.
Synthesis of indazol‐4,7‐dione derivatives as potential trypanocidal agents
Authors: Tapia Ricardo A. , Carrasco Claudia , Ojeda Scarlet , Salas Cristian , Valderrama Jaime A. , Morello Antonio , Repetto Yolanda
Published: March 2009

The synthesis of new indazol‐4,7‐dione derivatives via 1,3‐dipolar cycloaddition of diazomethane with 2,3‐dimethyl‐1,4‐benzoquinone (2) and 1,4‐naphthoquinone (7) followed by N‐alkylation of the pyrazol nitrogen atom of the corresponding quinones (3) and (8) with methyl chloroacetate is described. A series of amides from esters (5) and (10) were also obtained. These compounds were tested in vitro as potential anti‐trypanosomal agents. Compounds (4) and (8) were found to have significant activity.
Synthesis and ring transformation of substituted S‐(1‐phenylpyrrolidine‐2‐ones‐3‐yl)isothiuronium salts to substituted 2‐imino‐5‐[2‐(phenylamino)ethyl]thiazolidin‐4‐ones
Authors: Sedlák MiloŠ , Hanusek JiŘí , Macháček Vladimír , Hejtmánková Ludmila
Published: March 2009

Dedicated to Professor Jaromír Kaválek on the occasion of his 65th birthday

Substituted S‐(1‐phenylpyrrolidin‐2‐on‐3‐yl)isothiuronium salts in weakly basic media undergo intramolecular recyclisation reaction in which the γ‐lactam cycle is split and a thiazolidine cycle is formed. A series of six substituted 2‐imino‐5‐[2‐(phenylamino)ethyl]‐thiazolidin‐4‐ones have been prepared by this reaction.
Synthesis of novel 1,3,4‐oxadiazinane‐2‐thiones derived from (1R,2S‐ephedrine, (1S,2S)‐pseudoephedrine and (1R,2S)‐norephedrine
Authors: Hitchcock Shawn R. , Nora George P. , Casper David M. , Wiman Joseph D. , Bentley Jeromy T. , Stafford Carrie , Squire Michael D.
Published: March 2009

A several novel 1,3,4‐oxadiazinan‐2‐thiones have been synthesized by the cyclization of β‐hydrazino‐alcohols with either carbon disulfide or 1,1′‐thiocarbonyldiimidazole (TCDI).
Theoretical studies on the stereochemical course of 1,3‐dipolar cycloaddition of azomethine ylides derived from indol‐2,3‐dione and thiazolidine‐4‐carboxylic acid
Authors: Pardasani R. T. , Pardasani P. , Yadav S. K. , Bharatam P. V.
Published: March 2009

1,3‐Dipolar cycloadditon of azomethine ylides with different dipolarophiles leads to the formation of novel heterocyclic spiro compounds having two or more chiral centers. The theoretical studies (HF/3–21G) on the 1,3‐dipolar cycloaddition reaction between ethene and azomethine ylide A4 derived from isatin and thaizolidine‐4‐carboxylic acid, indicates that the energy barrier for this addition is about ∼ 8 kcal/mol higher than that in simplest azomethine ylide A1. HF/3–21G studies on a series of azomethine ylides A2 and A3 suggested that the increased barrier is mainly due to stabilization of azomethine ylides arising from aromatic indol nucleus. Semi‐empirical studies indicate that the cycloaddition is streocontrolled as the transition states corresponding to only the stericlly allowed paths could be located on the potential energy surface.
Ring transformations of heterocyclic compounds. XXIII. The UV irradiation product of photochromic 2,4,6‐triaryl‐1‐(spiro[2H‐l‐benzopyran‐2,2′‐indoline]‐6‐yl)pyridinium salts ‐ A phenolate betaine or a pyridinium substituted merocyanine dye?
Authors: Zimmermann Thomas , Brede Ortwin
Published: March 2009

The synthesis of the novel 2,4,6‐triaryl‐1‐(spiro[2H‐1‐benzopyran‐2,2′‐indoline]‐6‐yl)pyridiniumper‐chlorates 4 by reaction of 5‐nitrosalicylaldehydes 6 with 1,3,3‐trimethyl‐2‐methyleneindoline (7) to 6‐nitro‐spiro[2H‐1‐benzopyran‐2,2′‐indolines] 1, their stannous chloride reduction to the 6‐amino derivatives 8, followed by a 2,6‐[C5+N] ring transformation with 2,4,6‐triarylpyrylium perchlorates 9, is reported. UV irradiation experiments in twenty solvents of different polarity prove their photochromic properties and show that the photochemically generated negative solvatochromic dyes 5, formed by ring opening of the benzopyran moiety of 4, are rather merocyanine than pyridinium phenolate betaine dyes.
Synthesis and biological properties of 4‐substituted quinolin‐2(1H)‐one analogues
Authors: Jung Jae‐Chul , Oh Seikwan , Kim Won‐Ki , Park Woo‐Kyu , Kong Jae Yang , Park Oee‐Sook
Published: March 2009

A variety of 4‐substituted quinolin‐2(1H)‐ones were prepared and evaluated for N‐methyl‐D‐aspar‐tate (NMDA) receptor binding site activity and their abilities to inhibit neurotoxicity. The 4‐(2‐car‐bethoxyethanamino)‐7‐chloro‐3‐nitroquinolin‐2(1H)‐one (9b) exhibited favorable NMDA receptor binding site activity and 7‐chloro‐4‐(benzylamino)‐3‐nitroquinolin‐2(1H)‐one (9c) showed the most potent neurotoxicity among them. The synthetic strategies involve the use of well known keto ester condensation and reductive ring cyclization of intermediates (2a‐d) to afford 4‐substituted quinolin‐2(1H)‐ones.
Synthesis, characterization and crystal structures of two 2‐naphthyl substituted pyrazoles
Authors: Yang Guang , Raptis Raphael G.
Published: March 2009

The synthesis, characterization and X‐ray crystal structures of two 2‐naphthyl‐substituted pyrazoles ‐ 3‐(2‐naphthyl) pyrazole (1) and 5‐(2‐naphthyl)‐3‐trifluoromethyl‐pyrazole (3) ‐ are reported. In addition, the isolation and structural characterization of 5‐hydroxy‐3‐(2‐naphthyl)‐5‐trifluoromethyl‐4,5‐dihydropyrazole (2), an intermediate of the synthesis of 3, is included. Two simple methods of dehydration of 2 are also presented.
Synthesis and 15N NMR characterization of 4‐vinylbenzyl substituted bases of nucleic acids
Authors: Sedlák Miloš , Šimůnek Petr , Antonietti Markus
Published: March 2009

The following substances have been synthesized and characterized as monomers or intermediates for syntheses of new polymers: 1‐(4‐vinylbenzyl)uracil (1a), 1‐(4‐vinylbenzyl)thymine (1b), N‐4‐acetyl‐1‐(4‐vinylbenzyl)cytosine (1c), 1‐(4‐vinylbenzyl)cytosine (1d), 9‐(4‐vinylbenzyl)adenine (2a), 2‐amino‐9‐(4‐vinylbenzyl)‐6‐chloro‐9H‐purine (2b), and 9‐(4‐vinylbenzyl)‐guanine (2c). The alkylation reactions with 4‐vinylbenzyl chloride were catalyzed with anhydrous sodium iodide. The substitution at position 9 in substances 2a‐c was confirmed by 15N NMR.
Asymmetric diels alder reaction using pyrazole derivatives as a chiral catalyst
Authors: Kashima Choji , Miwa Yohei , Shibata Saori , Nakazono Hiroyuki
Published: March 2009

N‐Acylpyrazoles (1) were promising as good dienophiles, which were easily converted into the desired carboxylic derivatives. Bis(pyrazolyl)methanes, which were derived from chiral pyrazoles, showed the activity of chiral catalyst. Particularly 10 mol% of bis(isomenthopyrazol‐1,1′‐yl)methane (8a) catalyzed enantioselectively the Diels Alder reaction up to 40 % ee by the formation of complex with Mg(ClO4)2.
Enaminones as building blocks in heterocyclic syntheses: A new approach to polyfunctionally substituted cyclohexenoazines
Authors: Al‐Mousawi Saleh , John Elizabeth , Abdelkhalik Mervat Mohammed , Elnagdi Mohammed Hilmy
Published: March 2009

A variety of polyfunctionally substituted condensed pyridines and pyrazolotetrahydroquinazolines have been synthesized utilizing cyclic enaminones as starting materials.
The condensation of active methylene reagents with salicylaldehyde: Novel synthesis of chromene, azaanthracene, pyrano[3,4‐c]chromene and chromeno[3,4‐c]pyridine derivatives
Authors: Abu Elmaati Tarek M. , El‐Taweel Fathi M. , Elmougi Shymaa M. , Elagamey Abdelghani
Published: March 2009

On heating of the cyanoacetic acid cyclopentylidene hydrazide 1 with salicylaldehyde in the presence of bases the azaanthracene derivative 6 was formed. Also, reaction of 3 with malononitrile and ketones 10a,b afforded the pyrano[3,4‐c]chromene 9 and chromeno[3,4‐c]pyridine 11 respectively. A mechanism for these reactions is proposed.
Synthesis of dibenzo‐16‐crown‐5 compounds with pendant ester and ether groups
Authors: Babb David A. , Bartsch Richard A. , Collier James J. , Desai Dhimant H. , Elshania Sadik , Goo Mi‐Ja , Hallman Johnny L. , Heo Gwi Suk , Huang Xiaowu , Huber Vincent J. , Hwang Hong‐Sik , Johnson Russell J. , Liu Yung , Pugia Michael J. , Zhao Qiang
Published: March 2009

Structurally related dibenzo‐16‐crown‐5 lariat ethers with pendant ester and ether groups are prepared. Structural variations within the series of alkyl lariat ether esters include changes in the O‐alkyl group, attachment site and nature of the lipophilic group, and length of the spacer, which connects the ester group to the polyether framework. Also synthesized are bis(crown ether) diesters with two dibenzo‐16‐crown‐5 or two dicyclohexano‐16‐crown‐5 units and two ester groups connected to each other by a linker of varying length. Synthetic strategies for the preparation of these lariat ethers with pendant ester‐ and ether‐containing side arms are described.
Ring closure reactions of 3‐arylhydrazonoalkyl‐quinolin‐2‐ones to 1‐aryl‐pyrazolo[4,3‐c]quinolin‐2‐ones
Authors: Stadlbauers Wolfgang , Hojas Gerhard
Published: March 2009

4‐Hydroxy‐3‐arylhydrazonoalkyl‐2‐quinolones 6 or reactive derivatives such as 3‐arylhydrazonoalkyl‐4‐tosyloxy‐2‐quinolones 7 or 4‐chloro‐3‐arylhydrazonoalkyl‐2‐quinolones 14, which are obtained via 3‐acyl‐4‐hydroxyquinolones 4, 10 or 3‐phenylarrmomethylene‐quinoline‐2,4‐diones 12, cyclize in excellent yields to 1‐aryl‐pyrazolo[4,3‐c]quinolin‐4‐ones (11). The cyclization conditions were investigated by differential scanning calorimetry (DSC).
Dimethyldioxirane epoxidation of 3‐aryl‐1‐(3‐coumarinyl)propen‐1‐ones
Authors: Lévai Albert , Jekő JÓZsef , Brahmbhatt D. I.
Published: March 2009

Regioselective epoxidation of 3‐aryl‐1‐(3‐coumarinyl)propen‐1‐ones 1–10 by isolated dimethyldioxirane afforded the appropriate epoxides 11–20 in high (76–87%) yields.
Synthesis of highly symmetric mesomeric triazaphenalene betaines
Authors: Kafka Stanislav , Larissegger‐Schnell Barbara , Kappe Thomas
Published: March 2009

The synthesis of seven mesomeric triazaphenalene betaines 4a‐g by condensation reaction of hexahydro‐2H‐pyrimido[1,2‐a]pyrimidine 1 with diethyl malonates 2a‐g or with bis(2,4,6‐trichlorophenyl)malonates 3c,f has been achieved. The guanidine 1 forms in benzene solution a salt with trimethyl methanetricarboxylate 5 which upon heating produces 4a.
Synthesis and antiviral activity of new benzothiadiazine dioxide derivatives
Authors: Tait Annalisa , Luppi Amedeo , Cermelli Claudio
Published: March 2009

A series of 2,1,3‐ and 1,2,4‐benzothiadiazine derivatives were synthesized by alkylation via Mitsunobu reaction and evaluated for their antiviral activity against ADV, HHV‐6, Cox‐B5 and H‐CMV. Most of them were active at micromolar level against one or more viral strains. All the molecules studied are poorly cytotoxic (maximum non toxic concentrations were >25μM), except one compound that presents a higher cytotoxicity (maximum non toxic concentration was 6 μM).