bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fused s‐triazino heterocycles. XV. 13H‐4,6,7,13a,13c‐pentaazabenzo[hi]chrysene, 13H‐4,7,13a,13c‐tetraazabenzo[hi]chrysene, and 7H‐3,7,10,10b‐tetraazacyclohepta[de]naphthalene, three new ring systems
Authors: Shaw John T. , Corbett Wendy L. , Layman Deanna L. , Cuny Gregory D. , Kerschner Judith L. 
Published: April 2009

AbstractThe reaction of N‐cyano‐N′‐(6‐amino‐2‐pyridyl)acetamidine (5a) and homophthalic anhydride followed by ring closure of the 2‐[2‐(carboxymethyl)phenyl]‐5‐methyl‐1,3,4,6,9b‐pentaazaphenalene intermediate (4a) gave 5‐methyl‐13‐oxo‐13H‐4,6,7,13a,13c‐pentaazabenzo[hi]chrysene (8a). An analogous series starting with 3‐N‐(6‐amino‐2‐pyridyl)amino‐2‐cyano‐2‐butenenitrile (5b) in place of 5a gave in two steps 5‐methyl‐13‐oxo‐13‐H‐4,7,13a,13c‐tetraazabenzo[hi]chrysene‐6‐carbonitrile (8b). Elemental analysis, ir and pmr spectra of 8a, 8b and several new model compounds aided in confirming the structures of 8a and 8b. The synthesis of one of these model compounds for 5b and phenylacetic anhydride led surprisingly to 2‐methyl‐9‐phenyl‐7H‐3,7,‐10,10b‐tetraazacyclohepta[de]naphthalene (10) in addition to the expected 2‐benzyl‐4‐cyano‐5‐methyl‐1,3,‐6,9b‐tetraazaphenalene (7b).
Synthesis of 2‐amino‐4‐imino‐4,5‐dihydrothiazoles from N‐sulfonyl‐α‐chloroamidines and thiourea
Authors: Abdelaal Salma M. , Bauer Ludwig 
Published: April 2009

AbstractA number of new and interesting 2‐amino‐4‐(N‐substituted)imino‐4,5‐dihydrothiazoles were synthesized by reacting thiourea (or thiourea hydrochloride) with N‐alkyl‐ or N,N‐dialkyl‐N′‐p‐toluenesulfonyl‐α‐chloroacetamidines, where the N,N‐alkyl groups were ethyl, cyclohexyl, benzyl, β‐phenethyl, (3,5‐dimethyl‐1‐adamantyl)‐methyl, as well as N,N‐dimethyl‐ and N,N‐pentamethylene. Reactions of N‐alkyl‐N‐p‐toluenesulfonyl‐2‐chloroacetamidines (substituents being N‐ethyl, N‐benzyl and N,N‐dimethyl) with thiourea hydrochloride in hot 2‐propanol furnished 2‐amino‐4‐(p‐toluenesulfonyl)imino‐4,5‐dihydrothiazole (in 51, 60 and 65% yields, respectively) and the corresponding amine hydrochloride. In hot acetone or butanone, the reactions of these N‐sulfonyl‐2‐chloroacetamidines with excess thiourea provided 2‐amino‐4‐N‐(alkyl or N,N‐dialkyl)imminium‐4,5‐dihydrothiazole chlorides in 25–80% yield. The by‐product from these reactions was p‐toluenesulfonamide. The structures of the products were established by chemical transformations and spectral methods (nmr and mass spectra).
Syntheses of some hexacarboxylic acid derivatives of hexaazatriphenylene
Authors: Kanakarajan K. , Czarnik Anthony W. 
Published: April 2009

AbstractSynthetic methods and product characterizations for the conversions of 1,4,5,8,9,12‐hexaazatriphenylene‐hexacarboxylic acid to the corresponding triester triacid, triamic acid, triimide, triester triacid chloride, trimethyl triethyl hexaester, trimethyl ester tri(N,N‐dimethyrjamide, hexaamide, tri(N,N,‐dimethyr)amide triacid, tri(N,N‐dimethyl)amide triacid chloride, and trisphthalhydrazide derivatives are described.
A new synthesis of some indolecarboxylic acids
Authors: Baiocchi Leandro , Giannangeli Marilena 
Published: April 2009

Abstract1‐Substituted isatins are transformed into indole derivatives by means of ethyl chloroacetate. In fact, under the conditions of the Darzens reaction they give two glycidic ester isomers 4 and 5 which, by hydrolysis in alkaline medium, undergo a transposition to indole‐2,3‐dicarboxylic acids 2 together with minor amounts of indole‐3‐carboxylic acids 3. From isatin itself, 2,3‐dicarboxyindole‐1‐acetic acid (6) was obtained.
2,3,8,9‐Dibenzo‐5,6‐(substituted)benzo‐1,4‐dithio‐7‐azacyclonona‐2,5,8‐trienes. Synthesis and mechanistic study
Authors: Kim Kyongtae , Kim Man Nyoung 
Published: April 2009

Abstract5‐(2‐Acetamidoaryl)thianthreniumyl perchlorates reacted with potassium hydroxide in methanol at reflux giving 2,3,8,9‐dibenzo‐5,6‐(substituted)benzo‐1,4‐dithio‐7‐azacyclonona‐2,5,8‐trienes 4 in 43 to 75% yields, whereas the reactions of the same compounds with sodium hydride in the absence or in the presence of dimethyl sulfate in refluxing tetrahydrofuran gave N‐acetylated and N‐methylated 4 in 68 to 96% and 27 to 56% yields, respectively. The mechanism of the formation of the products might be explained by a nucleophilic attack of amide ions 10, 12, and 14 at the ipso‐position of the thianthrene ring. A sulfuranyl radical mechanism might be involved in these reactions.
Synthesis of phenylpyrrolylpyrroles. Part III
Authors: Dumoulin H. , Rault S. , Robba M. 
Published: April 2009

AbstractSeveral ethyl 3‐[(3‐aryl‐4‐methyl)‐2(1H)‐pyrrolyl]‐4‐methyl‐1H‐pyrrole‐2‐carboxylates have been synthesized using two successive ethyl isocyanide addition‐cyclizations to the appropriate nitropropene derivatives.
The synthesis and transformations of some 3‐thiocarbamoylthiazolidines
Authors: Malešič Mateja , Krbavčíč Ales , Golobič Amalija , Golič Ljubo , Stanovnik Branko 
Published: April 2009

AbstractIn connection with our studies on potential bioactive compounds some new polysubstituted 3‐thiocarbamoylthiazolidines 5, 6, 7, 9 and 10 were prepared in the reaction between 2‐(2‐methoxy‐phenyl)iminothiazolidine (2) and sulfamoylphenyl isothiocyanates 3 and 4a‐c. The structures for compounds 2 and 5 were established by X‐ray analyses, showing that the reaction is taking place at the endo‐cyclic nitrogen atom of thiazolidine ring.
Transformations of methyl L‐(—)‐thiazolidine‐4‐carboxylate, 2‐amino‐2‐thiazoline and 2‐aminothiazole into thiazoloazines and azolothiazoles
Authors: Malešíč Mateja , Krbačič Aleš , Stanovnik Branko 
Published: April 2009

AbstractIn the search for potential immunomodulators methyl L‐(—)‐thiazolidine‐4‐carboxylate (2), 2‐amino‐2‐thiazoline (12), and 2‐aminothiazole (19) were transformed into derivatives of various bicyclic systems. Thus, from compound 2 derivatives of perhydrothiazolo[3,4‐a]pyrazine 4 and 5, perhydrothiazolo[4,3‐c]‐[1,4]oxazine 7, and perhydroimidazo[1,5‐c]thiazole 9a,b, from compound 12 derivatives of 2,3‐dihydro‐thiazolo[2,3‐b]pyrimidine 13a,b, and from compound 19 derivatives of imidazo[2,1‐b]thiazole 21, 22, 24, and 25 were prepared. 6‐(p‐Sulfamoylphenyl)‐7‐oxoperhydroimidazo[1,5‐c]thiazole‐5‐thione (9a) was found to exhibit immunorestoration activity.
A new synthetic route to 7H‐imidazo[1,2‐b][1,2,4]triazoles
Authors: Lee Kee‐Jung , Song Dong‐Hyuk , Kim Dong‐Jin , Park Sang‐Woo 
Published: April 2009

AbstractThe reaction of benzil 1‐ureidoethylidene hydrazones 8 with a mixture of triphenylphosphine, carbon tetrachloride, and triethylamine provides a general route to 7H‐imidazo[1,2‐b][1,2,4]triazoles 18 via the thermal reaction of the expected keto azine carbodiimide intermediates 13, and the structure of 18 was confirmed by X‐ray crystallographic analysis.
AM1 computational study of cycloaddition reaction of vinyl sulfene generated from thiete 1,1‐dioxide
Authors: Jursic Branko S. 
Published: April 2009

AbstractTheoretical studies of the cycloaddition reaction between vinyl sulfene, norbornene and related systems are presented. Since the parameterized AMI semiempirical method was used, the generated data are only of qualitative value. The vinyl sulfene reactivity was assessed by using frontier molecular orbital (FMO) energy gaps, bond orders, and the charge distribution of the reactants. To obtain more information, as far as the reaction outcome and its feasibility, the transition state structures and activation barriers for competitive pathways are computed.
Manganese(III)‐mediated intermolecular cyclization reactions of alkenes and active methylene compounds
Authors: Ouyang Jie , Nishino Hiroshi , Kurosawa Kazu 
Published: April 2009

AbstractThe reactions of 1,1‐diphenylethene, 1,1‐bis(4‐chlorophenyl)ethene, 1,1‐bis(4‐methylphenyl)ethene, and 1,1‐bis(4‐methoxyphenyl)ethene with 3,5‐diacetyl‐2,6‐heptanedione in the presence of manganese(III) acetate in acetic acid at 80° yielded 4,6‐diacetyl‐8,8‐diaryl‐1,3‐dimethyl‐2,9‐dioxabicyclo[4.3.0]non‐3‐enes (41‐48%), 5‐acetyl‐2,2‐diaryl‐6‐methyl‐2,3‐dihydrobenzo[b]furans (20–21%), 3‐acetyl‐5,5‐diaryl‐2‐methyl‐4,5‐dihydrofurans (5–10%), and benzophenones (3–7%). Similarly, the reactions of 1,1‐diarylethenes with dimethyl 2,4‐diacetyl‐1,5‐pentanedioate or diethyl 2,4‐diacetyl‐1,5‐pentanedioate gave the corresponding 4,6‐bis(alkoxycarbonyl)‐8,8‐diaryl‐1,3‐dimethyl‐2,9‐dioxabicyclo[4.3.0]non‐3‐enes in moderate yields.
Synthesis of pyrroloazepines. Facile synthesis of 2‐substituted pyrrole derivatives by the phosgene method
Authors: Cho Hidetsura , Matsuki Shinsuke , Mizuno Akira , Annoura Hirokazu , Tatsuoka Toshio 
Published: April 2009

AbstractA highly convenient method for the synthesis of 2‐substituted pyrrole derivatives 7a‐c from pyrrole using phosgene was developed. Successively, 7‐methyl‐6,7‐dihydro‐1H,5H‐pyrrolo[2,3‐c]azepine‐4,8‐dione 1a and 6,7‐dihydro‐1H,5H‐pyrrolo[2,3‐c]azepine‐4,8‐dione 1b (aldisin) were synthesized by phosphorus pentoxide/methanesulfonate and polyphosphoric acid cyclization.
Reactions of benzotriazoles with diethyl ethoxymethylenemalonate; ethylation and michael addition. Comparison with other esters and N‐heterocycles
Authors: Sanna Paolo , Carta Antonio , Paglietti Giuseppe , Bacchi Alessia , Pelizzi Giancarlo 
Published: April 2009

AbstractBenzotriazole and its 5‐methyl‐and 5‐nitro derivatives react with diethyl ethoxymethylenemalonate by ethylation at each of the ring N‐atoms and through Michael addition, to give the isomeric esters ethyl (E/Z) 3‐[5(6)‐R‐benzotriazol‐1‐yl]propenoates. Benzotriazole and its 5‐nitro derivative react similarly with ethyl acetoacetate but N‐ethyl derivatives are obtained in lower yields. Other 1,2,3‐triazoles derivatives and indole were ineffective in this reaction while benzimidazole produced similar results but accompanied with a small amount of a benzimidazoline addition product, whose structure has been determined by crystallo‐graphic analysis.
Synthesis of 1,3‐diamino‐7,8,9,10‐tetrahydropyrido[3,2‐f]‐quinazolines. Inhibitors of Candida albicans dihydrofolate reductase as potential antifungal agents
Authors: Chan Joseph H. , Baccanari David P. , Tansik Robert L. , Boytos Christine M. , Rudolph Sharon K. , Brown Andrew D. , Hong Jean S. , Kuyper Lee F. , Jones Michael L. 
Published: April 2009

AbstractA series of novel 1,3‐diamino‐7,8,9,10‐tetrahydropyrido[3,2‐f]quinazolines were synthesized starting from 6‐amino‐5‐cyanoquinoline (4). These compounds inhibited Candida albicans dihydrofolate reductase with Ki values of ≤0.60 aM. One analogue exhibited moderate in vivo efficacy in a C. albicans‐infected mouse model.
Synthesis of 2‐substituted 4‐quinazolone‐5‐carboxylic acids as inhibitors of DNA‐gyrase
Authors: Sui Zhihua , Nguyen Van N. , Fernandez Jeff , Barrett John F. , Ohemeng Kwasi A. 
Published: April 2009

AbstractA series of 4‐quinazolone‐5‐carboxylic acids were designed as bacterial DNA gyrase inhibitors. The syntheses of the target compounds were accomplished by reacting 3‐aminophthalimide with aroyl chlorides followed by rearrangement of the resulting 3‐acylaminophthalimides under basic conditions. The designed compounds showed moderate DNA gyrase inhibitory activity.
The chemical properties of 1‐substituted 4‐oxopyrimidinium cations
Authors: Vedernikova Irina V. , Claeys Magda , Haemers Achiel , Peten Carl , Van Alsenoy Christian , Ryabukhin Yuryi I. 
Published: April 2009

AbstractSome theoretical aspects of electrophilic properties of 4‐pyrimidinium cations are discussed. The reactivity towards a series of C‐, H‐, N‐ and O‐nucleophiles is studied.
2‐Benzoyl‐2‐ethoxycarbonylvinyl‐1 and 2‐benzoylamino‐2‐methoxy‐carbonylvinyl‐1 as N‐protecting groups in peptide synthesis. Their application in the synthesis of dehydropeptide derivatives containing N‐terminal 3‐heteroarylamino‐2,3‐dehydroalanine
Authors: Svete Jurij , Aljaž‐Rožič Mateja , Stanovnik Branko 
Published: April 2009

AbstractEthyl 2‐benzoyl‐3‐dimethylaminopropenoate (6) and methyl 2‐benzoylamino‐3‐dimethylaminopropenoate (46) were used as reagents for the protection of the amino group with 2‐benzoyl‐2‐ethoxycarbonylvinyl‐1 and 2‐benzoylamino‐2‐methoxycarbonylvinyl groups in the peptide synthesis. Reactions of ethyl 2‐benzoyl‐3‐dimethylaminopropenoate (6) with α‐amino acids gave N‐(2‐benzoyl‐2‐ethoxycarbonylvinyl‐1)‐α‐amino acids 13–19. These were coupled with various amino acid esters to form N‐(2‐benzoyl‐2‐ethoxycar‐bonylvinyl‐1)‐protected dipeptide esters 20–31. The removal of 2‐benzoyl‐2‐ethoxycarbonylvinyl‐1 group, which was achieved by hydrazine monohydrochloride or hydroxylamine hydrochloride, afforded hydrochlo‐rides of dipeptide esters 32–41 in high yields. Similarly, the substitution of the dimethylamino group in methyl 2‐benzoylamino‐3‐dimethylaminopropenoate (46) by glycine gave N‐(2‐benzoylamino‐2‐methoxycar‐bonylvinyl‐1)glycine (47), which was coupled with glycine ethyl ester to give N‐[N‐(2‐benzoylamino‐2‐methoxycarbonylvinyl‐1)glycyl]glycine ethyl ester (48). Treatment of 48 with 2‐arnino‐4,6‐dirnethylpyrimi‐dine afforded N‐[glycyl]glycine ethyl ester hydrochloride (34) in high yield. Amino acid esters and dipeptide esters were employed in the preparation of tri‐ 58‐70, tetra‐ 71–82, and pentapeptide esters 83–85 containing N‐terminal 3‐heteroarylamino‐2,3‐dehydroalanine. 2‐Chloro‐4,6‐dimethoxy‐1,3,5‐triazine was employed as a coupling reagent for the preparation of peptides 58–85.
Nonlinear optical properties of benzofurobenzofurans
Authors: Millefiori Salvatore , Alparone Andrea , Millefiori Arcangelo 
Published: April 2009

AbstractThe geometric structure, dipole moment, μ, linear polarizability, α and first hyperpolarizability, β, of symmetrically substituted amino‐and cyanobenzofurobenzofurans and dihydrobenzofurobenzofurans have been calculated by ab initio coupled perturbed Hartree‐Fock methods. Singlet electronic transition energies and excited state dipole moments have been calculated by the AMI program. The benzofurobenzofuran derivatives are planar, while dihydrobenzofurobenzofuran derivatives have a V‐shaped form, in agreement with experimental X‐ray data. The molecular structure is rather unaffected by substitution. The linear polarizability is weakly sensitive to the substituent and substituent position, while β value changes over about 1 order of magnitude. Although both series of compounds have relatively modest hyperpolarizability, reaching ca. 60% β of para‐nitroaniline, they have good properties for second harmonic generation devices: transparency in the visible spectral region, thermal stability and conformational rigidity.
Alkylation of 4,5‐dichloropyridazin‐6‐one with α,ω‐dibromoalkanes or 4,5‐dichloro‐1‐(ω‐bromoalkyl)pyridazin‐6‐ones
Authors: Kim Sung‐Kyu , Cho Su‐Dong , Kweon Deok‐Heon , Yoon Yong‐Jin , Kim Jung‐Ho , Heo Jung‐Nyoung 
Published: April 2009

AbstractAlkylations of 4,5‐dichloropyridazin‐6‐one (1) with dibromoalkanes 2 or 3 in the presence of potassium carbonate or tetrabutylammonium bromide/potassium hydroxide were investigated under restricted condition. Reactions of 1 with 2 or 3, except for 2b and 3b, in the presence of potassium carbonate or tetrabutylammonium bromide/potassium hydroxide gave only the N‐alkylation products 3 and/or 4. Alkylation of 1 with 2b or 3b in the presence of potassium carbonate yielded the N‐alkylation products 3b and/or 4b and the O‐alkylation product 5 as the main product, whereas treatment of 1 with 2b or 3b in the presence of tetrabutylammonium bromide/potassium hydroxide afforded selectively the N‐alkylation products 3b and/or 4b.
Palladium(0)‐catalyzed allylation of heterocycles with cyclopentene derivatives
Authors: Arnau N. , Cortés J. , Moreno‐Mañas M. , Pleixats R. , Villarroya M. 
Published: April 2009

AbstractPalladium(0)‐catalyzed allylation of imidazoles, 6‐methyluracil, 2‐pyrimidinone, and Meldrum's acid with cyclopentadiene monoepoxide and cis‐cyclopentene‐3,5‐diol mono and dicarbonate is described.
2,4,6‐Triphenylpyridine as a neutral leaving group in the palladium(0)‐catalyzed allylation of nucleophiles
Authors: Moreno‐Mañas M. , Mortal L. , Pleixats R. 
Published: April 2009

AbstractPalladium(0)‐catalyzed allylation of nucleophiles such as morpholine, sodium dimethyl malonate and 2,6‐dimethylaniline can be achieved under very mild conditions using N‐allyl‐2,4,6‐triphenylpyridinium tetrafluoroborates as allylating reagents in reactions in which 2,4,6‐triphenylpyridine acts as the neutral leaving group.
Studies on pyrrolidinones. Synthesis of some bioisosteres of 3,3,5‐trimethylcyclohexyl pyroglutamate
Authors: Rigo Benoǐt , Laruelle Claude 
Published: April 2009

AbstractThe synthesis of new N‐(4‐chlorobenzyl) and N‐(4‐chlorobenzoyl)pyroglutamic esters and amids whose the structure conserves the main structural features of the cholesterol lowering agent crilvastatin is described.
Synthesis of thienothiazocinoisoindolediones and thienothiazinoisoindolones from mercaptothiophenes and chloromethylphthalimide
Authors: Netchitaïlo Pierre , Othman Mohamed , Decroix Bernard 
Published: April 2009

Abstract2‐Thienylthiomethylphthalimides 3a,b were synthesized by action of Chloromethylphthalimide on 2‐or 3‐mercaptothiophene. Reduction of 3a,b and Wittig reaction using carbethoxycarbonyltriphenyl‐phosphorane gave the corresponding acetic acids 5a,b which cyclized under Friedel and Crafts conditions to lead the thienothiazocinoisoindolediones 6a,b. Thienothiazinoisoindolones 7a,b were obtained from hydroxyisoindolones derivatives 4a,b in acid conditions via an acyliminium ion.
Synthesis of ethyl 2‐aminodihydro‐5‐pyrimidinecar‐boxylate derivatives and 3,7‐diethoxycarbonyl‐4,6‐dihydro‐2,4,6,8‐tetraaryl‐1H‐pyrimido[1,2‐a]pyrimidines
Authors: Milcent René , Malanda Jean‐Claude , Barbier Géo , Vaissermann Jacqueline 
Published: April 2009

AbstractReactions of ethyl 3‐aryl‐2‐benzoylpropenoates 1 with guanidine andN‐alkyl(or benzyl)guanidines have been investigated. Ethyl 2‐aminodihydro‐5‐pyrimidinecarboxylate derivatives 3, 4 or 5, and 3,7‐diethoxy‐carbonyl‐4,6‐dihydro‐2,4,6,8‐tetraaryl‐1H‐pyrimido[1,2‐a]pyrimidines6have been synthesized.
An expedient synthesis of (±)‐2‐amino‐3‐(3‐hydroxy‐5‐methylisoxazol‐4‐yl)propionic acid hydrobromide via a 3‐bromoisoxazole intermediate
Authors: Hanson Robert N. , Mohamed Farid A. 
Published: April 2009

AbstractThe excitatory, amino acid ±2‐amino‐3‐(3‐hydroxy‐5‐methylisoxazol‐4‐yl)propionic acid hydrobromide was prepared in gram quantities in an 3.3% overall yield from methylbut 2‐ynoate. The key step was the facile preparation of methyl 3‐bromo‐5‐methylisoxazole‐4‐carboxylate.
Tetracyclic systems: Synthesis of isoindolo[1,2‐b]thieno‐[2,3(3,2 or 3,4)‐e][1,3]thiazocines and Isoindolo[2,1‐a]thieno‐[2,3(3,2 or 3,4)‐f][1,4] and [1,5]diazocines
Authors: Pigeon Pascal , Decroix Bernard 
Published: April 2009

AbstractCyclization of thioglycolic acids derivatives 3a‐d gave isoindolo[1,2‐b]thieno[2,3(3,2 or 3,4)‐e][1,3]‐thiazocines 4a‐d. Isoindolo[2,1‐a]thieno[2,3(3,2 or 3,4)‐f][1,4] or [1,5]diazocines 10b or 11a‐c were synthesized from Beckmann or Schmidt rearrangement of the ketones 7a‐c.
Mass spectrometric behaviour of 1‐imino‐substituted pyrazolo[1,2‐a]‐[1,2,4]triazoles under electron and chemical ionization
Authors: Joutsiniemi Karoliina , Vainiotalo Pirjo , Morgenstern Olaf , Klemann Anke 
Published: April 2009

AbstractThe spectra of five pharmacologically interesting substituted pyrazolo[1,2‐a][1,2,4]triazole hydroiodides were measured under electron and chemical ionization. In the electron ionization spectra, in addition to the intense molecular ion peak of the free base (M+*), there was also a relatively intense molecular ion peak of the hydroiodide form, which is unusual since the hydroiodides are rarely so stable. The phenylimino and phenylamino substituents of the triazole ring affected the fragmentation behaviour of the compounds very much. The chemical ionization reagent gases used in this work were methane, isobutane, deuterated ammonia and acetone. In all the cases practically only [M+H]+ions were observed, the only exception being acetone which also gave rise to intense [M+C2H3O]+and [M+C3H7O]+adduct ions. None of the reagent gases used was able to cause any fragmentation.
Synthesis of 2‐aminoquinazolines from ortho‐fluorobenzaldehydes
Authors: Hynes John B. , Campbell Johnny P. 
Published: April 2009

AbstractThe reaction of guanidine carbonate with various ortho‐fluorobenzaldehydes in N,N‐diinethylacetamide was investigated as a potential route for preparing 2‐aminoquinazolines. Eleven new 2‐aminoquinazolines were elaborated in this manner in low to moderate yields. In general the best results were obtained with ortho‐fluorobenzaldehydes possessing an electron withdrawing substituent at the other ortho position. Complex mixtures were obtained using 2‐fluorobenzaldehyde, 2,5‐difluorobenzaldehyde and 2‐fluoro‐5‐methoxybenzaldehyde which were not resolved.
Bicyclic [b]‐heteroannulated pyridazine derivatives.4. Cyclization reactions of 4‐aryltetrahydropyridazine‐3,6‐dione 3‐hydrazones with some keto esters
Authors: Lange Jerzy , Pytlewska Elzbieta , Plenkiewicz Jan , Kulinski Tomasz , Karolak‐Wojciechowska Janina , Rump Slawomir 
Published: April 2009

AbstractEthoxycarbonylalkylidene derivatives2and6of the title hydrazones were obtained in the reaction with ethyl pyruvate or ethyl aroylformate and ethyl acetoacetate, respectively, in methanol. Both compounds were mixtures of geometric isomers with high predominance of one of them. Nmr spectroscopy revealed an unexpected magnetic non‐equivalence of the CH2protons in the ester ethyl group of the major isomer of6. On heating (˜200°) in an inert medium or on refluxing in ethanolic sodium ethoxide2cyclized to the corresponding pyridazino[6,1‐c]‐triazines4, whereas6formed pyrazolylpyridazines7. The structure of the latter was unambigously established by X‐ray analysis. Alkylation of4awith benzyl bromide in the presence of tetrabutylammonium bromide occurred selectively on the pyridazineNatom.
A new and efficient route to amino derivatives of [1,6]‐ and [2,7]naphthyridones
Authors: Nemazany Alexei , Haider Norbert 
Published: April 2009

AbstractReaction of N‐substituted amides of 2‐chloro‐ or 4‐chloronicotinic acid with CH‐acidic nitriles in the presence of a base provides a convenient access to amino derivatives of 1,6‐naphthyrid‐5(6H)‐one, compounds of type 4 and 5, or 2,7‐naphthyrid‐1(2H)‐one 7.
Organic syntheses based on 2‐oxoglutaric acid. V. Syntheses of novel 2H‐1,4‐benzothiazines and a 2,5‐dihydro‐1,5‐benzothiazepine
Authors: Blitzke Torsten , Sicker Dieter , Wilde Horst 
Published: April 2009

AbstractSyntheses aimed on the incorporation in heterocycles of segments originating in the precursor 2‐oxoglutaric acid are described. Cylocondensation of dimethyl 2‐oxoglutarate 1, dimethyl 3‐bromo‐2‐oxoglutarate 2, and dimethyl (E)‐2‐oxoglutaconate 3 with 2‐aminobenzenethiol gave rise to the novel 2H‐1,4‐benzothiazines 4 and 5, and the 2,5‐dihydro‐1,5‐benzothiazepine 6, respectively, by incorporation of either the segments C‐1/C‐2 or C‐2/C‐3 or C‐3/C‐4/C‐5 of the precursor.