bluuebunny/crossref_metadata_2025_split huggingface dataset:
A facile synthesis of 2,7‐diazapyrene
Authors: Sotiriou‐Leventis Chariklia , Mao Zhan 
Published: March 2009

Abstract2,7‐Diazapyrene is synthesized in three high‐yield steps from commercially available 1,4,5,8‐naphthalene tetracarboxylic dianhydride, which first reacts with concentrated ammonium hydroxide solution at room temperature to give 1,4,5,8‐naphthalenetetracarboxylic diimide (96%). The latter compound is subsequently reduced with borane in refluxing tetrahydrofuran to give 1,2,3,6,7,8‐hexahydro‐2,7‐diazapyrene (77%), which in turn is oxidized with manganese dioxide in refluxing benzene giving 2,7‐diazapyrene (71%).
Convenient substitution of hydroxypyridines with trifluoroacetaldehyde ethyl hemiacetal
Authors: Gong Yuefa , Kato Katsuya , Kimoto Hiroshi 
Published: March 2009

AbstractThermal 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

AbstractStereoselective 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

AbstractA 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

AbstractFourteen 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

AbstractCarbazole (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

AbstractA 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

AbstractNew 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

AbstractThe 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

AbstractThe 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

AbstractThe 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

AbstractCalixarene 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

AbstractTreatment 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.
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

AbstractThe 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

AbstractA 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

AbstractThe 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

Abstractω‐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

AbstractSome 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

AbstractN‐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

AbstractA 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

AbstractThe 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

AbstractMacrocyclic 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

AbstractFused 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

AbstractSulfonium 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

Abstracto‐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

AbstractThe 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

Abstract1‐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

AbstractThe 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

AbstractAs 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.