bluuebunny/crossref_metadata_2025_split huggingface dataset:
The synthesis of syn‐ and anti‐2(S)‐phthalimido‐methyl‐2,3,4,4a,7,7a‐hexahydro‐6‐oxo‐5H‐pyrano‐[2,3‐b]pyrroles as rigid β‐bend peptide‐mimetics
Authors: Krstenansky John L. , Del Rosario‐Chow Michelle , Currie Bruce L. 
Published: March 2009

AbstractThe synthesis of the syn‐ 14 and anti‐ 13 isomers of 2(S)‐phthalimidornethyl‐2,3,4,4a,7,7a‐hexahydro‐6‐oxo‐5H‐pyrano[2,3‐b]pyrrole was accomplished starting from sodium 3,4‐dihydro‐2H‐pyran‐2‐carboxylate. The isomers were separated by preparative high performance liquid chromatography. Both isomers can serve as β‐bend mimetics and represent three amino acids plus the amino group of the fourth amino acid of a peptide. The lactam nitrogen was alkylated to provide the equivalent of a leucine as the fourth amino acid residue.
Unusual formation of a novel pyrrolo[1′,2′:1,2]pyrido[3,4‐b]indole
Authors: Giri Venkatachalam S. , Das Sankar K. , Sankar Parasuraman Jai , Shoolery James N. , Keifer Paul 
Published: March 2009

AbstractReaction of 1‐methyl‐3,4‐dihydro‐β‐carboline 1 with methyl glycidate 4 gave the novel tetracyclic conjugated γ‐lactam, 2‐methylpyrrolo[1′,2′:1,2]pyrido[3,4–6]indol‐3‐one 5. The same compound 5 was obtained in higher yield when 1 was treated with methyl 2‐methoxyacrylate 7. Sodium borohydride treatment of 5 resulted in the cleavage of lactam to yield the unexpected alcohols 8 and 9.
Tricyclic heteroaromatic systems. 5H‐1,2,4‐triazolo[5,1‐c][1,4]benzodiazepine
Authors: Melani F. , Cecchi L. , Colotta V. , Catarzi D. , Filacchioni G. 
Published: March 2009

AbstractThe synthesis of the new tricyclic heteroaromatic system 5H‐1,2,4‐triazolo[5,1‐c][1,4]benzodiazepine, diazaanalogue of 5H‐pyrrolo[2,1‐c][1,4]benzodiazepine, which is the common feature of some antitumor antibiotics, is reported. The structure of the new tricyclic system and of some of its key intermediates is assigned by means of nuclear magnetic resonance studies.
Synthesis of lipophilic crown ethers with pendant phosphonic acid or phosphonic acid monoethyl ester groups
Authors: Czech Bronislaw P. , Desai Dhimant H. , Koszuk Jacek , Czech Anna , Babb David A. , Robison Thomas W. , Bartsch Richard A. 
Published: March 2009

AbstractSynthetic routes to fifteen lipophilic crown ether phosphonic acid monoethyl esters and nine lipophilic crown ether phosphonic acids are described. For both classes of crown ethers which have pendant, protonionizable groups, the crown ether ring sizes are systematically varied from 12‐crown‐4 and 24‐crown‐8.
Synthesis and antibacterial activity of new 5‐substituted 1‐cyclopropyl‐6‐fluoro‐7‐piperazinyl‐1,4‐dihydro‐4‐oxo‐1,8‐naphthyridine‐3‐carboxylic acids
Authors: Remuzon Philippe , Bouzard Daniel , Di Cesare Pierre , Dussy Christian , Jacquet Jean‐Pierre , Jaegly Alexandre 
Published: March 2009

AbstractThe 5‐hydroxymethyl and the 5‐formyl‐1‐cyclopropyl‐6‐fluoro‐7‐piperazinyl‐1,4‐dihydro‐4‐oxo‐1,8‐naphthyridine‐3‐carboxylic acids have been prepared via a 5‐trimethylsilyl group and were tested in vitro as potential antibacterials.
Synthesis of substituted 1H‐pyrrolo[3,2‐c]quinolines
Authors: Park Kwanghee Koh , Rapoport Henry 
Published: March 2009

Abstract1H‐2‐Phenylpyrrolo[3,2‐c]quinoline (1a) is made by thermal cyclization of quinol‐4‐yl hydrazone. Subsequent substitution of the C‐3 hydrogen atom of the pyrrole ring of 1a with chlorine and a formyl group is easily achieved by reacting 1a with trichloroacetyl chloride and phosphorus oxychloride in DMF, respectively.
K‐region oxides and imines of benzo[b]phenanthro[2,3‐d]thiophene and benzo[b]phenanthro[3,2‐d]thiophene
Authors: Blum Jochanan , Shalom Yosef , Harvey Ronald G. 
Published: March 2009

AbstractThe syntheses of the K‐oxides and K‐imine derivatives of benzo[b]phenanthro[2,3‐d]thiophene and benzo‐[b]phenanthro[3,2‐d]thiophene are described. The parent hydrocarbons 1 and 2 were oxidized with osmium tetroxide and sodium metaperiodate, and the dialdehydes 12 and 18 so formed, cyclized to the corresponding epoxides 1a,12b‐dihydrobenz[b]oxireno[9,10]phenanthro[2,3‐d]thiophene (7) and 1a,12b‐dihydrobenz‐[b]oxireno[9,10]phenanthro[3,2‐d]thiophene (13). Reaction of the oxiranes with sodium azide gave mixtures of azido‐alcohols that, in turn, were transformed to the thiaarene imines 1a,12b‐dihydro‐1H‐benz[b]azirino‐[9,10]phenanthro[2,3‐d]thiophene (8) and 1a,12b‐dihydro‐1H‐benz[b]azirino[9,10]phenanthro[3,2‐d]thiophene (14), respectively, with the aid of tri‐n‐butylphosphine.
N,N‐Coupled heterobicycles from cyclic hydrazine derivatives. Part 6. Electron ionization mass spectrometry of some substituted 1‐thiocarbamoyl and 1‐carbamoylpyrazolidines
Authors: Vainiotalo P. , Morgenstern O. , Richter P. H. 
Published: March 2009

AbstractThe electron ionization mass spectra of six substituted 1‐thiocarbamoyl and four substituted 1‐carbamoyl‐pyrazolidines were measured and carefully analyzed. The fragmentation pathways were elucidated by metastable ion analysis and exact mass measurement. The principal fragmentations were the same for all the compounds studied. The related importance of different decomposition channels, however, varied according to the structure of the compounds. Some substituents also prompted fragmentations unique to them. The most important reaction was the loss of the thiocarbamoyl or carbamoyl substituent with simultaneous hydrogen atom migration from the (thio)carbamoyl nitrogen to the ring nitrogen giving rise to ionized pyrazolidine at m/z 72. In this process for 1‐(N‐arylthiocarbamoyl)pyrazolidines the charge tended to remain with the substituent part of the molecule. Moreover for all the compounds studied [M‐2H]+. ion peaks formed by dehydrogenization of the original compounds were observed.
Acetylene chemistry. Part 29. A convenient synthesis of 9‐(n‐alkynyl)acridinamines via a nucleophilic displacement reaction between 9‐chloroacridine and N‐alkynyl amines
Authors: Reisch Johannes , Kamal G. M. , Gunaherath B. 
Published: March 2009

AbstractThree new 9‐(N‐alkynyl)acridinamines 5, 6 and 7 have been synthesized from 9‐chloroacridine using a simple aromatic nucleophilic substitution reaction.
An efficient synthesis of 6‐formyl‐1,2‐dihydro‐2‐oxo‐3‐pyridinecarboxylic acid and some carbonyl derivatives of it and its 6‐acetyl homologue
Authors: Sanchez Joseph P. , Mich Thomas F. , Huang Gin G. 
Published: March 2009

AbstractStarting with 1,1‐dimethoxy‐2‐propanone (1), 6‐formyl‐1,2‐dihydro‐2‐oxo‐3‐pyridinecarboxylic acid (5a) has been prepared in large quantities by a highly efficient, 4‐step synthesis. This compound, along with its one carbon homologue, 6‐acetyl‐1,2‐dihydro‐2‐oxo‐3‐pyridinecarboxylic acid (5b) has been reacted with several carbonyl derivative forming reagents to provide a series of side chains for β‐lactams. Among these carbonyl derivatives are styrylamides which were prepared from Wittig and Horner‐Emmons reagents. The preparation of the phosphonium salts and phosphonate esters is also described.
Formation of an 6α, 14‐epoxy‐bridged isomorphinan, an unusual product from a substituted 6α,14‐dihydroxymorphinan
Authors: Davis Ronda D. , Nelson Timothy D. , Nelson Wendel L. 
Published: March 2009

AbstractDuring alkylation of 3‐O‐benzyl‐6α‐naltrexol (1) with large aralkyl halides like 2‐bromomethylnaphthalene and 9‐chloromethylanthracene under phase transfer catalysis conditions (potassium hydroxide, tetrabutylammonium bromide, methylene chloride), formation of a new 6α,14‐epoxide‐bridged isomorphinan (4) was noted. Chemical and spectral evidence, including nmr and mass spectral data, are presented to prove its structure. Its formation results from 6α‐oxygen displacement of a 14‐O‐aralkyl ether intermediate under the phase transfer catalysis alkylation conditions.
Condensation reactions of aryl acyloins with ureas in ethylene glycol
Authors: Kim Yong Boon , Kim Chung Soo , Lee Chang Kiu 
Published: March 2009

Abstract4,5‐Diaryl‐4‐imidazolin‐2‐ones were prepared in good yield by heating aryl acyloins with ureas in eth‐ylene glycol for 0.5‐2 hours. 4,4′‐Dimethoxybenzoin and 2,2′‐pyridoin gave 4‐oxazolin‐2‐one derivatives in addition to 4‐imidazolin‐2‐ones.
On the two isomeric tris(perchlorothienyl)methyl radicals
Authors: Gronowitz Salo , Temciuc Marcel , Eberson Lennart 
Published: March 2009

AbstractThe two isomeric tris(trichlorothienyl)carbinols have been synthesized. Upon treatment with acid the tris(trichlorothienyl)carbenium ions were formed, which upon reduction with iodide gave the tris(trichlorothienyl)methyl radicals, which were studied by epr‐spectroscopy. The β‐isomer, the tris(2,4,5‐trichloro‐3‐thienyl)methyl radical, was much more stable than the α‐isomer and showed great similarity to the perchlorotrityl radical.
He I and He II spectra of 2‐halopyridines
Authors: Caine Gavin R. , Dunne Simon J. , Von Nagy‐Felsobuki Ellak I. 
Published: March 2009

AbstractThe He I and He II ultraviolet photoelectron spectra of 2‐fluoro‐, 2‐chloro‐, 2‐bromo‐, and 2‐iodopyridine have been recorded and interpreted in terms of a composite‐molecule model. The sequence of the four lowest ionization energies for 2‐fluoro‐ and 2‐chloropyridine is: π3 (1a2) > nN (11a1) > π2 (2b1) > πpyr (7b2), whereas for 2‐bromo‐ and 2‐iodopyridine the assignment is: π3 (1a2) ‐ πX > nN (11a1) > πX > π2 (2b1), where X represents a bromine and iodine lone‐pair. Comparison of the He I and He II band intensities confirmed this assignment. However, ab initio calculations at the STO‐3G*/STO‐3G* and 6–31G**/STO‐3G* levels did not agree with the sequence predicted by either the composite‐molecule model, simple correlations and the He I/He II cross‐section ratios. For the 2‐fluoropyridine, a comparison using the HAM/3 model was found to be in agreement with this assignment.
New organic nitrates. II. Synthesis of 2H‐pyrido[2,3‐e]‐1,3‐oxazine‐2,4(3H)‐diones, 2H‐pyrido[4,3‐e]‐1,3‐oxazine‐2,4(3H)‐diones, 2H‐pyrido[4,3‐e]‐1,3‐oxazin‐4(3H)‐ones, 2H‐thieno[2,3‐e]‐1,3‐oxazin‐4(3H)‐ones and 2H‐thieno[3,4‐e]‐1,3‐oxazin‐2,4(3H)‐diones
Authors: Benedini Francesca , Bertolini Giorgio , Ferrario Francesco , Motti Angelo , Sala Alberto , Somenzi Flavio 
Published: March 2009

AbstractThe preparation and the physico‐chemical characterization of 2H‐pyrido[2,3‐e]‐1,3‐oxazine‐2,4(3H)‐diones, 2H‐pyrido[4,3‐e]‐1,3‐oxazine‐2,4(3H)‐diones, 2H‐pyrido[4,3‐e]‐1,3‐oxazin‐4(3H)‐ones, 2H‐thieno[2,3‐e]‐1,3‐oxazin‐4(3H)‐ones and 2H‐thieno[3,4‐e]‐1,3‐oxazine‐2,4(3H)‐diones are reported.
Synthesis of new 1,2,4‐triazolines and 1,3,4‐thiadiazolines from bithioureas
Authors: Ernst Steffen , Richter Christian , Hobert Annette , Mariam Getachew G. , Schulze Klaus 
Published: March 2009

Abstract2,4‐Disubstituted thiosemicarbazides 1 react with acyl isothiocyanates to give bithioureas 2, which by the action of sodium ethanolate cyclize to 1,2,4‐triazoline‐3‐thiones 3 and 5, respectively. Treatment of 2 with methyl iodide yields 1,3,4‐thiadiazoline‐2‐imines 8 isomeric with 3. Compound 8d undergoes a thermal induced DIMROTH rearrangement to give 3d in good yield.
Reactivity of 7‐(2‐dimethylaminovinyl)pyrazolo[1,5‐a]pyrimidines: Synthesis of pyrazolo[1,5‐a]pyrido[3,4‐e]pyrimidine derivatives as potential benzodiazepine receptor ligands. 2
Authors: Bruni Fabrizio , Selleri Silvia , Costanzo Annarella , Guerrini Gabriella , Casilli Maria Lucia , Giusti Laura 
Published: March 2009

AbstractA series of pyrazolo[1,5‐a]pyrido[3,4‐e]pyrimidin‐6‐ones was obtained by reaction of ammonium acetate with ethyl 7‐dimethylaminovinylpyrazolo[1,5‐a]pyrimidine‐6‐carboxylates and these had been prepared from ethyl 7‐methylpyrazolo[1,5‐a]pyrimidine‐6‐carboxylates by reaction with dimethylformamide dimethylacetal. Under these conditions the compounds bearing a 2‐hydroxy group were also O‐alkylated. During the preparation of the ethyl 2‐hydroxy‐7‐methyl‐3‐phenylpyrazolo[1,5‐a]pyrimidine‐6‐carboxylate the corresponding 5‐methyl isomer was isolated and identified.
Photoreaction of pyrido[2,3‐c]furoxan
Authors: Miyazawa Tomoyuki , Takabatake Tohru , Hasegawa Minoru 
Published: March 2009

AbstractWhen pyrido[2,3‐c]furoxan 4 was irradiated in acetonitrile containing a little water with a low pressure mercury lamp, 3‐nitro‐2‐pyridone 5 was obtained. When compound 4 was irradiated in the presence of morpholine with a low pressure mercury lamp in an argon atmosphere, 6‐morpholinopyridine 2,3‐dioxime 6, 6‐morpholinopyrido[2,3‐c]furazan 7, 3‐amino‐6‐morpholino‐2‐nitropyridine 8, and 3‐amino‐4,6‐dimorpholino‐2‐nitropyridine 9 was produced. The results of photoreaction study indicated the only photo‐product to be compound 6. The main difference between these two reactions may be considered due to the behavior of nitrogen in the pyridine ring.
Reaction of N1, N2‐diarylamidines with chloranil and 2,3‐dichloro‐1,4‐naphthoquinone
Authors: Döpp Dietrich , Gomaa Mohsen Abdel‐Motaal , Henkel Gerald , El‐Din Ahmed Mokhtar Nour 
Published: March 2009

AbstractNucleophilic attack by N2 of N1 N2‐diarylformamides 1a‐c on C‐2 of chloranil (2) and subsequently by N1 on C‐1 of 2 initiates the formation of benzimidazolinones 8a‐c. In contrast, when 1b‐e is reacted with 2,3‐dichloro‐1,4‐naphthoquinone (9), both chlorine atoms are successively substituted by the two nitrogen atoms and 2‐(arylamino)‐3‐(N‐formylarylamino)‐1,4‐naphthoquinones 13b‐e result, which (probably via their cyclic tautomers 12b‐e) may be cyclodehydrogenated to form N1,N3‐diarylnaphtho[2,3‐d] imidazoline‐2,4,9‐triones (as 14b,c). On the other hand, N1,N2diarylacetamidines 15a‐d attack 2 and 9 at C‐2 with N2 but subsequently exert nucleophilic character at the acetamidine α‐carbon attacking C‐1 of 2 and 9, respectively, thus forming 1‐aryl‐2‐(arylimino)‐3a‐hydroxy‐2,3,3a,6‐tetrahydro‐1N‐indol‐6‐ones 18a‐d and 3‐aryl‐2‐(arylimino)‐9b‐hydroxy‐2,3,5,9b‐tetrahydro‐1‐H‐benz[e]indol‐5‐ones 19b,c, respectively. The latter may be thermally dehydrated to the fully conjugated 2,5‐dihydro‐3H‐benz[e]indol‐5‐ones 20b,c. Unambiguous structural assignments for 18b and 20c are made on the basis of X‐ray crystal structure analyses.
Furopyridines. xvi. Photo[2+2]cycloaddition of furo‐[3,2‐c]pyridin‐4(5H)‐one with acrylonitrile
Authors: Shiotani Shunsaku , Tsukamoto Youichi 
Published: March 2009

AbstractThe photocycloaddition of furo[3,2‐c]pyridin‐4(5H)‐one (1) and its N‐methyl derivative (1‐Me) to acrylonitrile has been studied. The structures of the photoadducts isolated by column chromatography were determined on the basis of the nuclear magnetic resonance spectroscopy. The cycloaddition of 1 afforded an adduct 2 at the carbonyl oxygen and four possible isomers 3a, 3b, 3c and 3d of cyclobutane‐fused adduct at the 6‐ and 7‐position of 1, and the addition of 1‐Me the N‐methyl derivatives 3a‐Me, 3b‐Me, 3c‐Me and 3d‐Me.
New syntheses of diaza‐crown ethers using boc protecting groups
Authors: Krakowiak Krzysztof E. , Bradshaw Jerald S. 
Published: March 2009

AbstractBOC‐protected m‐xylylenediamine was treated with tetraethyleneglycol ditosylate to form BOC‐protected diazabenzo‐18‐crown 5 (5) in a good yield. BOC‐protected diazabenzo‐21‐crown‐6 (6) was prepared in the same manner from BOC‐protected m‐xylylenediamine and pentaethylene glycol ditosylate. Bis‐BOC‐protected diaza‐17‐crown‐5 (12) was prepared by treating BOC‐protected 1,4‐diaminobutane with 1,11‐diiodo‐3,6,9‐trioxaundecane. The BOC‐protecting groups were removed in methanolic 2 N hydrogen chloride to form the corresponding diaza‐crown ethers 7, 8 and 13.
Synthesis and nitration of some thieno‐fused analogues of the benzo[a]quinolizinium cation
Authors: Sato Kiyoshi , Arai Sadao , Yamagishi Takamichi 
Published: March 2009

AbstractThree thieno‐fused analogues of benzo[a]quinolizinium (1), thieno[3,2‐a]‐ and thieno[2,3‐a]quinolizinium 4 and 5 and thiazolo[2,3‐a]isoquinolinium (6), were synthesized by photocyclization of 1‐(2‐thienylvinyl)pyridinium salts 9a and 9b and 3‐styrylthiazolium salt 9c, respectively. The nitration of the compounds 4, 5, and 6 occurred predominantly at positions 2, 3, and 7, respectively, while the nitro group was introduced into the 8‐ and 10‐positions of 1 in the ratio of 68:32. The nmr and uv spectral properties and reduction potentials of 4–6 were also compared with those of the parent compound 1.
Synthesis of 3‐(2‐guanidinoethyl) and 3‐[2‐(S‐methylisothioureidoethyl)] analogs of 5‐isopropyl 2,6‐dimethyl‐1,4‐dihydro‐4‐(2,3‐dichlorophenyl)pyridine‐3,5‐dicarboxylate as a respective releaser of nitric oxide and inhibitor of nitric oxide synthase
Authors: Iqbal Nadeem , Knaus Edward E. 
Published: March 2009

AbstractThe Hantzsch condensation of 2‐azidoethyl acetoacetate with 2,3‐dichlorobenzaldehyde and isopropyl 3‐aminocrotonate afforded 3‐(2‐azidoethyl) 5‐isopropyl 2,6‐dimethyl‐1,4‐dihydro‐4‐(2,3‐dichlorophenyl)pyridine‐3,5‐dicarboxylate (7). Reduction of the 3‐(2‐azidoethyl) moiety of 7 using 5% palladium‐on‐calcium carbonate and hydrogen gas gave the 3‐(2‐aminoethyl) derivative 8, which was subjected to guanylation using 1H‐pyrazole‐1‐carboxamidine hydrochloride to yield the target 3‐(2‐guanidinoethyl) analog 9. The 3‐(2‐aminoethyl) product 8 was elaborated to the title compound 3‐[2‐(S‐methylisothioureidoethyl)] 5‐isopropyl 2,6‐dimethyl‐1,4‐dihydro‐4‐(2,3‐dichlorophenyl)pyridine‐3,5‐dicarboxylate hydrochloride (12) via the intermediate 3‐(2‐thioureidoethyl) compound 10. The 3‐(2‐guanidinoethyl 9 and 3‐[2‐(S‐methylisothioureidoethyl)] 12 compounds were about 116‐ and 23‐fold less potent calcium channel antagonists, respectively relative to the reference drug nifedipine.
Synthesis and total 1H‐NMR assignment of naphtho[1′,2′:4,5]thieno[2,3‐c][1,10]phenanthroline and naphtho[2′,1′:4,5]‐thieno[2,3‐c] [1,10]phenanthroline
Authors: Halverson Aileen Pfleider , Castle Lyle W. , Castle Raymond N. 
Published: March 2009

AbstractNaphtho[1′,2′:4,5]thieno[2,3‐c][1,10]phenanthroline and naphtho[2′,1′:4,5]thieno[2,3‐c][1,10]phenanthroline, two novel polycyclic heterocyclic ring systems, have been synthesized in four steps from known starting materials. The total 1H nmr spectral assignments were made using a COSY experiment to identify the spin systems.
Synthesis and spectroscopic characterisation of 4,5‐dihydro‐[1,2,3]triazolo[5,1‐f][1,2,4]triazines. A novel condensed heterocyclic ring system
Authors: Laskos Efstathios , Lianis Pygmalion S. , Rodios Nestor A. 
Published: March 2009

AbstractThe reaction of the 5‐bromomethyl‐1‐dibenzoylamino‐1,2,3‐triazole (5) with aromatic amines gave the corresponding 5‐arylaminomethyl‐1‐benzoylamino‐1,2,3‐triazoles 9, which on treatment with phosphorus pentachloride gave the [1,2,3]triazolo[5,1‐f][1,2,4]triazine derivatives 10. Hydrolysis of the amide bond in 9 gave the 1‐aminotriazoles 11, which with ethyl orthoformate gave the [1,2,3]triazolo[5,1‐f][1,2,4]triazines 12, whereas with phosgene the triazolotriazinones 13 were obtained. The spectroscopic characteristics of all the new compounds are also given.
The nitration of some 1‐aryl(or benzyl)pyrroles
Authors: Korakas D. , Varvounis G. 
Published: March 2009

AbstractNitration of 1‐arylpyrroles 1a‐c with acetyl nitrate, and 1‐arylpyrroles, 1a‐e and 1‐(2‐ethoxycarbonylbenzyl)pyrrole 4 with trifluoroacetyl nitrate gave the corresponding 2‐nitro isomers 2a‐e and 5, and 3‐nitro isomers 3a‐e and 6. 3‐Nitropyrroles 3d and 3e were further nitrated with a mixture of nitric and sulfuric acids to give compounds 10, 11 and 12, respectively. Under the same conditions 1‐(2‐ethoxycarbonylbenzyl)‐3‐nitropyrrole 6 gave derivative 13.
The synthesis of 5‐acyl‐4‐aryl(alkyl)‐2‐aryl‐1,2,3‐triazole 1‐oxides by lead tetraacetate oxidation of mono‐ and bisarylhydrazones of α‐hydroxyimino‐β‐diketones
Authors: Hadjiantoniou‐Maroulis Constantina P. , Ikonomou Vassiliki , Parisopoulou Evi 
Published: March 2009

AbstractThe synthesis and lead tetraacetate oxidation of the title mono‐ and bis‐arylhydrazones to the corresponding 5‐acyl‐4‐aryl(alkyl)‐2‐aryl‐1,2,3‐triazole 1‐oxides is described.
NMR spectroscopic investigations with isatin guanylhydrazones
Authors: Holzer Wolfgang , Györgydeák Zoltan 
Published: March 2009

AbstractThe synthesis of some novel (substituted) guanylhydrazones of isatin, 5‐methylisatin and 1‐methylisatin is decribed. Moreover, detailed nmr‐spectroscopic studies (1H‐nmr, 13C‐nmr) with these compounds and previously known congeners are presented.
A simple and general method for the synthesis of novel hetarenonaphthyridones
Authors: Nemazany Alexei , Haider Norbert 
Published: March 2009

AbstractReaction of hetarylacetonitriles 1 with ethyl esters of chloro‐ or bromo‐substituted pyridinecarboxylic acids in the presence of a base affords a series of novel heterocycle‐annelated [1,6]‐, [2,6]‐, and [2,7]naphthyridones with a bridgehead nitrogen atom.
1‐Phenyl‐4(1H)‐quinazolinones and 2,3‐dihydro‐1‐phenyl‐4(1H)‐quinazolinones as potential cholecystokinin receptor ligands
Authors: Pentassuglia Giorgio , Bertani Barbara , Donati Daniele , Ursini Antonella 
Published: March 2009

AbstractA series of new l‐phenyl‐4(1H)‐quinazolinones and 2,3‐dihydro‐1‐phenyl‐4(1H)‐quinazolinones were synthesized and tested as cholecystokinin receptor ligands. All the compounds showed moderate affinity and 1‐phenyl‐4(1H)‐quinazolinones resulted more effective towards the cholecystokinin‐B receptor, meanwhile the dihydro derivatives were generally more effective towards the cholecystokinin‐A receptor.
Unexpected rearrangement products from animations of 5‐bromo‐2‐nitrothiazole
Authors: Lee Ho H. , Palmer Brian D. , Boyd Maruta , Denny William A. 
Published: March 2009

AbstractWhile reaction of 2‐bromo‐5‐nitrothiazole (2) with weakly basic secondary aliphatic amines gives the expected 2‐amino products from nucleophilic displacement of the bromine, reaction of the isomeric 5‐bromo‐2‐nitrothiazole (3) with such amines gives mixtures of the expected 5‐amino products together with 2‐aminated 5‐nitrothiazole rearrangement products. The identity of the latter were detemined by alternative synthesis, and by X‐ray crystallographic determination of a derivative. The mechanism proposed is a slow thermal isomerization of 5‐bromo‐2‐nitrothiazole (3) to the much more reactive 2‐bromo‐5‐nitro isomer 2 which competes, in the case of relatively weak amine nucleophiles, with the direct (but slow) nucleophilic displacement of the 5‐bromo group to form the normal displacement products.
Conformational analysis of 4‐(2′‐furyl)‐2‐(methylamino)pyrimidine
Authors: Mokrosz Jerzy L. , Bojarski Andrzej J. , Harden Donald B. , Strekowski Lucjan 
Published: March 2009

AbstractConformational transformations of the title compound 1 were studied using high‐resolution 1H‐nmr techniques, semi‐empirical PM3 calculations and molecular dynamics. The unfused furan‐pyrimidine ring system of 1 predominantly exists in an s‐trans conformation in solution and the considerable sp2 character of the C2amino bond results in the hindered rotation which is observed on the nmr time scale.
New process for the synthesis of UP 269‐6, a 1,2,4‐triazolo[1,5‐c]pyrimidine derivative as a potent orally active angiotensin ii antagonist
Authors: Boyer T. , Fournel L. , Nicolaï E. , Teulon J. M. 
Published: March 2009

AbstractA new synthetic route to prepare the 2‐hydroxy‐5‐methyl‐7‐n‐propyl‐8‐[[2′‐(1H‐tetrazol‐5‐yl)biphenyl‐4‐yl]methyl]‐[1,2,4]triazolo[1,5‐c]pyrimidine (UP 269‐6, Ripisartan) is described. UP 269‐6 is a non‐peptide angiotensin II antagonist currently in phase II clinical trials for the treatment of hypertension and chronic heart failure. Its development needed a suitable process for industrial production. The laboratory scale synthesis was optimized and particularly two key steps: 4‐hydrazinopyrimidine formation without isolation of the 4‐chloro intermediate and its cyclization into triazolo[1,5‐c]pyrimidine derivative without isolation of the triazolo[4,3‐c]pyrimidine isomer using urea in N‐methylpyrrolidone at 160°C. This cyclization process affords a new and efficient way to prepare directly 2‐hydroxytriazolo[1,5‐c]pyrimidine without isolation of the corresponding triazolo[43‐c]pyrimidine.