bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractThe 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

AbstractThe 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

AbstractNew 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

AbstractReaction 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

AbstractSulfur 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

AbstractThe 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

AbstractDerivatives 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

AbstractThe 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

AbstractNew 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

AbstractTreatment 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

AbstractN‐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

AbstractIododerivatives 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

AbstractDepending 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

AbstractIn 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

AbstractSeveral 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

AbstractThe 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

AbstractThe 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

AbstractDedicated 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.
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

AbstractThe 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

AbstractDedicated to Professor Jaromír Kaválek on the occasion of his 65th birthdaySubstituted 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

AbstractA 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

Abstract1,3‐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

AbstractThe 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

AbstractA 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

AbstractThe 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

AbstractThe 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

AbstractN‐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

AbstractA 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

AbstractOn 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

AbstractStructurally 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

Abstract4‐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

AbstractRegioselective 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

AbstractThe 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.