bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pyridinethiones. XI. Diastereoselective aldol condensations with 2(1H)‐pyridones, 2(1H)‐pyridinethiones, and the crystal structure of 3‐(1‐hydroxy‐2‐methyl‐3‐oxo‐3‐(4‐chlorophenyl)propyl‐1‐isoprpyl‐2(1H)‐pyridinethione
Authors: Becher Jan , Asaad Fahmy M. , Johansen Tea , Hansen Jesper , Larsen Sine , Hansen Flemming 
Published: May 2009

AbstractAldol condensation of 3‐formyl‐2(1H)‐pyridinethiones and the corresponding pyridones with ketones such as acetophenones in aqueous base yields 3‐hydroxy‐1‐propanones in high yields. Reaction with propiophenone showed this reaction to be highly diastereoselective as only the erythro‐isomer is formed at room temperature. This assignment was based on an X‐ray crystallographic investigation of the compound given in the title. Aldol condensations of a number of related 3‐acetyl‐2(1H)‐pyridinethiones with benzaldehyde yielded the corresponding trans‐vinyl ketones.
Synthesis and thermal rearrangement of allylic 3,5,6‐trimethyl‐2‐pyrazinylacetates: A heterocyclic carroll rearrangement
Authors: Podraza Kenneth F. 
Published: May 2009

AbstractThe synthesis of allylic 3,5,6‐trimethyl‐2‐pyrazinylacetates 2–4 has been achieved by the reaction of 3,5,6‐trimethyl‐2‐pyrazinylacetic acid lithium salt (1) with phenyl dichlorophosphate followed by addition of the allylic alcohol. On thermolysis, the allylic β‐heteroaromatic esters underwent a rearrangement, analogous to the Carroll rearrangement, to generate the corresponding γ,δ‐unsaturated heteroaromatic compound. The configuration of the double bond formed in the product was the E‐isomer. The rate of the rearrangement was dependent on the substitution pattern of the allylic portion of the molecule with 4>2>3. The ester enolate version of the heterocyclic Carroll rearrangement was investigated with 2, however these conditions did not promote the rearrangement.
Reactivity of pyrazolo[4,3‐c][1,2,5]oxadiazin‐3(5H)‐ones toward C‐nucleophiles: Synthesis of pyrazolo[3,4‐b]pyrazines
Authors: Giori P. , Veronese A. C. , Poli T. , Vicentini C. B. , Manfrini M. , Guarneri M. 
Published: May 2009

AbstractThe reaction of pyrazolo[4,3‐c][1,2,5]oxadiazin‐3(5H)‐ones 1 with carbanions prepared in situ from compounds containing an activated methylene group afforded pyrazolo[3,4‐b]pyrazines 4–13 in good yields. The possible reaction mechanism is proposed and discussed.
Synthesis of benzophenothiazinone derivatives from 2,3,5‐trisubstituted‐1,4‐naphthoquinones with 2‐aminothiophenol
Authors: Nan'Ya Seiko , Maekawa Eturǒ , Kang Wen‐Bing , Ueno Yoshio 
Published: May 2009

AbstractThe 1‐substituted‐5H‐benzo[2,3‐a]phenothiazin‐5‐one, 4‐substituted‐5H‐benzo[6,5‐a]phenothiazin‐5‐one and 6‐substitutedbenzo[a][1,4] benzothiazino[3,2‐c]phenothiazine derivatives were prepared by the condensation of 5‐substituted‐2,3‐dichloro‐1,4‐naphthoquinones with 2‐aminothiophenol. Reduction, acetylation and dehalogenation of the resulting compounds were carried out and the structures of the products were inferred from comparison with the authentic compound.
Synthesis of 9,10,12,13,14,14a‐hexahydrodibenzo[f,h]pyrrolo‐[2,1‐a]isoquinoline
Authors: Copado C. Rodolfo , Grande G. Mercedes T. , Trigo Gregorio G. , Söllhuber K Mónica M. 
Published: May 2009

AbstractThe synthesis of 9,10,12,13,14,14a‐hexahydrodibenzo[f,h]pyrrolo[2,1‐a]isoquinoline6has been accomplished by a sequence involving as a key step the Friedel‐Crafts intramolecular acylation of the amino acid9to the corresponding pentacyclic aminoketone10. Compounds7, 11and12showed a significant protein synthesis inhibitory effect.
A facile one step synthesis of novel ethyl 2,6‐bis(trifluoromethyl)‐4‐hydroxypyrimidine‐5‐carboxylate
Authors: Sing Y. Larry , Lee Len F. 
Published: May 2009

AbstractTrifluoroacetonitrile was condensed with diethyl malonate to give a novel ethyl 2,6‐bis(trifluoromethyl)‐4‐hydroxypyrimidine‐5‐carboxylate (2) in 88% yield. Derivations of 2 are also described.
A novel synthesis of 3‐bromo‐1,2,4‐oxadiazoles
Authors: Humphrey Guy R. , Wright Stanley H. B. 
Published: May 2009

AbstractA novel synthesis of 3‐bromo‐1,2,4‐oxadiazoles by 1,3‐dipolar cycloaddition between bromocyanogen oxide and alkyl and aryl nitriles is described.
O‐Alkylations of pyridoxine and pyridoxamine
Authors: Ueda Taisei , Nakaya Kenji , Nagai Shin‐Ichi , Sakakibara Jinsaku 
Published: May 2009

AbstractO‐Alkylations of pyridoxine 1 and pyridoxamine 5 were carried out in acetone in the presence of sodium ethoxide and potassium iodide to give 5‐alkoxy‐6‐methyl‐3,4‐(bishydroxymethyl)pyridines 2a‐j and 5‐alkoxy‐4‐aminomethyl‐6‐methyl‐3‐hydroxyrnethylpyridines 6a‐e.
“One pot” synthesis of 2‐substituted 9‐(2′‐hydroxy‐3′‐aminopropyl)‐8‐azahypoxanthines and 8‐azaadenines (5‐substituted 3‐(2′‐hydroxy‐3′‐aminopropyl) 7‐amino and 7‐hydroxy‐3H‐1,2,3‐triazolo[4,5‐d]pyrimidines)
Authors: Biagi G. , Franchi M. , Giorgi I. , Livi O. , Scartoni V. 
Published: May 2009

AbstractAn example of the generalization of the synthesis of 8‐azahypoxanthines A and 8‐azaadenines B, interesting from a medicinal point of view, is presented by utilizing l‐amino‐2‐hydroxy‐3‐azidopropanes.
Tricyclic heteroaromatic systems. 1,2,3,4‐tetrahydropyrazolo[4,3‐c][l]benzazepin‐1‐ones as potential antitumor agents
Authors: Palazzino Giovanna , Cecchi Lucia , Colotta Vittoria , Melani Fabrizio , Filacchioni Guido 
Published: May 2009

AbstractThe synthesis of 1,2,3,4‐tetrahydropyrazolo[4,3‐c][1]benzazepin‐1‐ones 1 and that of its 10‐methyl derivative 2 is reported. The preparation of the latter from 3‐(2‐aminobenzyl)3‐pyrazolin‐5‐one and triethyl ortho‐formate gave as the main product a derivative of the new tricyclic ring system, pyrazolo[1,5‐c][1,3]benzo‐diazepine. The structures of the new compounds synthesized were assigned by means of a 13C nmr study.
The use of NMR measurements in the orientation of pyrrolic substitution in 5,6‐dihydro‐7‐methyl‐6‐oxopyrrolo[1,2a]‐[3,1,6]benzothiadiazocine
Authors: Cobb J. , Cheeseman G. W. H. , Varvounis G. 
Published: May 2009

AbstractThe title compound 1, has been shown to give a 1‐bromo derivative 2 when subjected to free‐radical bromination and a 1‐dimethylaminomethyl derivative 3 by reaction under standard Mannich conditions. Vilsmeier formylation, however, furnishes the 3‐substituted derivative 4.
Anticancer anthrapyrazoles. Improved syntheses of clinical agents CI‐937, CI‐941, and piroxantrone hydrochloride
Authors: Beylin Vladimir G. , Colbry Norman L. , Goel Om P. , Haky Jerome E. , Johnson Donald R. , Johnson Judith L. , Kanter Gerald D. , Leeds Robert L. , Leja Boguslawa , Lewis Edward P. , Rithner Christopher D. , Showalter H. D. Hollis , Sercel Anthony D. , Turner William R. , Uhlendorf Susan E. 
Published: May 2009

AbstractImproved processes for the synthesis of bulk quantities of the anthrapyrazole clinical agents CI‐937, CI‐941, and piroxantrone hydrochloride are reported. Reported also are detailed analytical and spectroscopic data for these agents and intermediates of the synthetic sequences.
Synthesis of ortho‐substituted aminopyridines. Metalation of pivaloylamino derivatives
Authors: Estel L. , Linard F. , Marsais F. , Godard A. , Quéguiner G. 
Published: May 2009

AbstractThe three isomeric pivaloylaminopyridines were lithiated in more than 80% yields. Aminopyridine derivatives were treated by 2.5‐3 equivalents of the complex BuLi‐TMEDA at −10° in diethyl ether. Reaction of the lithiated species with various electrophiles afforded a number of ortho‐substituted pivaloylaminopyridines in good yields. Secondary pyridine alcohols were oxidized to the corresponding aminopyridyl ketones. Pyridopyrimidines, benzonaphthyridines as well as an analogue of the natural antitumor alkaloid ellipticine has been synthesized showing the versatility of the method.
A simplified procedure for preparing 3,5‐disubstituted‐1,2,4‐oxadiazoles by reaction of amidoximes with Acyl chlorides in pyridine solution
Authors: Chiou Shishue , Shine Henry J. 
Published: May 2009

Abstract3‐R‐5‐R′‐1,2,4‐Oxadiazoles are prepared in fair to good yield by short‐time, one‐pot reaction of an amidoxime, RC(NH2)NOH, with an acyl chloride, R'COCl, in pyridine solution. Precipitation of the oxadiazole occurs on diluting the pyridine reaction solution with water. Ordinary acyl chlorides can be used; they do not have to be unusually reactive to succeed in the one‐pot preparation. The procedure is simpler and more convenient than the conventional one, namely isolation and thermal rearrangement of an O‐acylamidoxime.
Amidrazones. 12. Formation of 3‐acylamino‐4,5‐dihydro‐1,1‐dimethyl‐1H‐pyrazolium salts by acid‐promoted cyclization of N3‐acylated derivatives of acrylamide dimethylhydrazone and (E)‐cinnamamide dimethylhydrazone
Authors: Smith Richard F. , Augustine Brian H. , Dennis Lisa A. , Ryan William J. , Liptak Stephen C. , Capparelli Brian R. 
Published: May 2009

AbstractN3‐Acylated derivatives of acrylamide dimethylhydrazone 3a,b and (E)‐cinnamamide dimethylhydrazone 3c,d cyclized, on treatment with hydriodic acid or p‐toluenesulfonic acid, to give 3‐acylamino4,5‐dihydro‐1,1‐dimethyl‐1H‐pyrazolium salts 4a‐d.
Reactions of some quinazoline compounds with ethoxymethylenemalonic acid derivatives
Authors: Deady Leslie W. , Mackay Maureen F. , Werden Dianne M. 
Published: May 2009

AbstractThe reactions of ethyl (1,4‐dihydro‐4‐oxoquinazolin‐2‐yl)acetate 4 and 2‐aminoquinazolin‐4(1H)‐one 5 with diethyl ethoxymethylenemalonate (EMME), (ethoxymethylene)malononitrile (EMMN) and ethyl (ethoxymethylene)cyanoacetate (EMCA) are reported, and rather different results are obtained to those previously found with quinoline analogs. Reaction of 4 with EMME gives a pyrido[1,2‐a]quinazoline, while with EMMN and EMCA ethyl 2‐(pyridin‐2‐yl)aminobenzoates are formed, presumably by ring‐opening of intermediate pyrido[2,1‐b]quinazolines. Reaction of 5 with EMME likewise results in ultimate cyclization onto N‐1 of the quinazoline, while the EMMN and EMCA reactions give isolable pyrimido[2,1‐b]quinazolines. These are readily cleaved under mild conditions.
Pyridazines with heteroatom substituents in position 3 and 5. 3. 2‐aryl‐5‐hydroxypyridazin‐3(2H)‐ones as potential herbicides: Synthesis and some reactions
Authors: Schober Bernt D. , Megyeri Gabor , Kappe Thomas 
Published: May 2009

AbstractThe coupling of dimethyl acetonedicarboxylate 1 with a variety of aryldiazonium salts 2a‐i produces the hydrazones 3a‐i which can be cyclized in boiling dichlorobenzene to yield the pyridazone esters 4a‐i, or in sodium hydroxide solution to give the pyridazone acids 5a‐f,h,i, which can be decarboxylated at elevated temperatures. The hydroxy group in 4a,d can be acylated, sulfonated or alkylated yielding compounds 8a‐n. Condensation of 4a,d with magic malonates 9a‐d produces the pyronopyridazinones 10a‐f. The reaction of 4a with hydrazine yields the hydrazide 12 via the salt 11, and with ammonia the amide 14.
Synthesis of 1,2,4‐triazole, 1,2,4‐triazolo[3,4‐b][1,3,4]thiadiazole and 1,2,4‐triazolo[3,4‐b][1,3,4]thiadiazine derivatives of benzotriazole
Authors: El‐Khawass S. M. , Habib N. S. 
Published: May 2009

AbstractA novel series of 1‐(1‐carbonylmethyl‐1H‐benzotriazole) thiosemicarbazides 3a‐e was synthesized and then cyclized with sodium hydroxide to afford 1‐(4‐substituted‐4H‐1,2,4‐triazole‐3‐thion‐5‐yl)methyl‐1H‐benzotriazoles 4a‐e, which were alkylated with ethyl iodide to l‐(3‐ethylthio‐4‐substituted‐4H‐1,2,4‐triazol‐5‐yl)‐methyl‐1H‐benzotriazoles 5b‐e. The reaction of 1H‐benzotriazol‐1‐acetic acid hydrazide (2) with carbon disulphide and potassium hydroxide followed by hydrazine hydrate gave 1‐(4‐amino‐4H‐1,2,4‐triazole‐3‐thion‐5‐yl)methyl‐1H‐benzotriazole (6). Its subsequent condensation with carboxylic acids in the presence of phosphorus oxychloride or with phenacyl bromides afforded two series of fused heterocycles namely; 6‐substituted‐3‐[1‐(1H‐benzotriazole)methyl]‐1,2,4‐triazolo[3,4‐b][1,3,4]thiadiazoles 7a‐e and 6‐substituted phenyl‐3‐[1‐(1H‐benzotriazole)methyl]‐7H‐1,2,4‐triazolo[3,4‐b][1,3,4]thiadiazines 8a‐e respectively. The structure of the newly synthesized compounds was elucidated by elemental analyses, ir and nmr spectra.
Color change (yellow \documentclass{article}\pagestyle{empty}\begin{document}$\rightleftharpoons$\end{document} orange) of 4,6,7‐tri(alkoxy‐substituted aryl)‐1,2,5‐thiadiazolo[3,4‐c]pyridines in the solid phase
Authors: Mataka Shuntaro , Takahashi Kazufumi , Tashiro Masashi , Lin Wei‐Hua , Iwasaki Shin‐Ichi , Tsutsui Tetsuo , Saito Shogo , Akiyama Shinji , Yonemitsu Tadashi 
Published: May 2009

AbstractReversible color change of 4,6,7‐tri(alkoxy‐substituted phenyl)‐1,2,5‐thiadiazolo[3,4‐c]pyridines 5 in the solid state was observed: on grinding, yellow crystals of 5 became an orange amorphous solid which, on heating or washing with an appropriate solvent, gave the original yellow crystals.
Synthesis of an acetyl‐α‐thio‐β‐carboline by thermolysis of dithio‐2,2′‐di(N′‐acetyltryptamine)
Authors: Barbier Michel , Devys Michel 
Published: May 2009

AbstractThe first synthesis of an acetyl‐α‐thio‐β‐carboline [2‐acetyl‐2,9‐dihydro‐1,2‐thiazino[6,5‐b]indole (4) 28%] by the thermolysis of dithio‐2,2′‐di(N′‐acetyltryptamine) 3 is reported. Deacetylation of 4 carried out in basic or acidic media does not lead to the free base but to a series of unidentified degradation products. This new substance 4 is therefore stabilized by the N‐acetyl group. The results so far obtained are discussed and a mechanism is proposed for the cyclisation produced by the thermolysis.
Synthesis and characterization of macrocyclic ligands containing benzene and/or pyridine rings and their nickel(II), copper(II) and zinc(II) complexes
Authors: Hashimoto Mamoru , Tagami Hidetoshi , Sakata Kazunori 
Published: May 2009

AbstractMacrocycles, 7,16‐diethyl‐5,6,7,8,9,14,15,16,17,18‐decahydrodibenzo[b,i][1,4,8,11]tetraazacyclotetradecine (2B), 7,16‐diethyl‐5,6,7,8,9,14,15,16,17,18‐decahydro‐(E)dipyrido[b,i][1,4,8,11]tetraazacyclotetradecine (2E) and 7,16‐diethyl‐5,6,7,8,9,14,15,16,17,18‐decahydro‐(Z)‐dipyrido[b,i][1,4,8,11]tetraazacyclotetradecine (2Z), have been synthesized by hydrogenation of 7,16‐diethyl‐5,14‐dihydrodibenzo[b,i][1,4,8,11]tetraazacyclotetradecine and 7,16‐diethyl‐5,14‐dihydro‐(E)‐ or ‐(Z)‐dipyrido[b,i][1,4,8,11]tetraazacyclotetradecine. In each case, two isomers were produced with differing orientations of the ethyl groups relative to the macrocyclic plane. The isomers were separated by repeated recrystallization. Carbon‐13 nmr spectra for the metal‐free ligands were used to distinguish between the two isomers. The nickel(II), copper(II) and zinc(II) complexes of the two isomers of 2B were prepared and their spectroscopic data were determined. The ligand‐field bands in the 15000–30000 cm−1 region for the nickel(II) and copper(II) complexes are consistent with square‐planar configurations. A strong band appearing at ca. 3200 cm−1 in the infrared spectra was assigned to the N‐H stretching mode which shifted to lower frequency upon metal coordination.
Substituent effects on the photocycloaddition reactions of phenol to benzonitriles
Authors: Al‐Jalal N. A. 
Published: May 2009

AbstractMethoxy‐, methyl‐, and chloro‐substituted benzonitriles undergo photocycloaddition to phenol to give substituted 1,2‐dihydroazocin‐2‐ones III, by initial attack of the cyano group on the aromatic ring of the phenol. The efficiency of the photocycloaddition reaction varied with the position of the substituents, with the para‐substituted ones giving the largest amount of photoproduct.
Diheterocyclic compounds from dithiocarbamates and derivatives thereof. V. 4,4′‐dioxo‐2,2′‐dithioxo(dioxo)‐6,6′‐biquinazolines
Authors: Garín Javier , Meléndez Enrique , Merchán Francisco L. , Merino Pedro , Orduna Jesús , Tejero Tomás , Viñegra Milagros 
Published: May 2009

AbstractThe title compounds 3, 5 and 9 were synthesized in a one step procedure from dithiocarbamates 2 or dithiocarbonimidates 7 in medium to high yields. The usefulness of 2 and 7 as synthetic equivalents of unstable or unavailable isocyanates and isothiocyanates is also discussed.
Synthesis of dl‐guinesines and related compounds
Authors: Mitsudera Hiroyuki , Uneme Hideki , Okada Yoshiyuki , Numata Mitsuo , Kato Atsushi 
Published: May 2009

AbstractGuinesines A, B and C were synthesized starting from 1,3‐bis(benzylthio)‐2‐propanone and N‐methyl‐2,2‐diethoxypyrrolidine.
Synthesis of acyclic nucleoside analogs of 6‐substituted 2‐aminopurines and 2‐amino‐8‐azapurines
Authors: Párkányi Cyril , Yuan Hui Liang 
Published: May 2009

AbstractSeveral new acyclonucleoside purine and 8‐azapurine analogs have been prepared from 2‐amino‐4,6‐dichloropyrimidine (1) and 3‐amino‐1,2‐propanediol (2a) and 4‐amino‐1‐butanol (2b), respectively, as the starting materials. The new target compounds are: 2‐amino‐6‐chloro‐9‐(2,3‐dihydroxypropyl)purine (6a), 2‐amino‐6‐chloro‐9‐(4‐hydroxybutyl)purine (6b), 2‐amino‐6‐chloro‐9‐(2,3‐dihydroxypropyl)‐8‐azapurine (7a), 2‐amino‐6‐chloro‐9‐(4‐hydroxybutyl)‐8‐azapurine (7b), 9‐(2,3‐dihydroxypropyl)‐8‐azaguanine (8a), 9‐(4‐hydroxybutyl)‐8‐azaguanine (8b), 9‐(2,3‐dihydroxypropyl)‐8‐azathioguanine (9a), and 9‐(4‐hydroxybutyl)‐8‐azathioguanine (9b). Also, the requisite intermediate pyrimidine derivatives, 2,5‐diamino‐4‐(2,3‐dihydroxypropylamino)‐6‐chloropyrimidine (5a) and 2,5‐diamino‐4‐(4‐hydroxybutylamino)‐6‐chloropyrimidine (5b) are novel.
A new synthetic approach to the C‐D ring portion of streptonigrin analogues
Authors: Kilama John J. , Iyengar Bhashyam S. , Remers William A. , Mash Eugene A. 
Published: May 2009

AbstractDevelopment of an efficient synthesis of the C‐D ring portion of streptonigrin is a key operation in the synthesis of this antibiotic and its analogues. A new method for the synthesis of 3‐cyano‐5,6‐dimethyl‐4‐(3,4,5‐trimethoxyphenyl)‐2‐pyridone (14), a compound having the requisite functionality for conversion into a streptonigrin analogue, has been established. It involves treatment of 3,4,5‐trimethoxybenzonitrile with ethylmagnesium bromide and malononitrile to give propylenemalononitrile derivative 7, which is condensed with trimethyl orthoacetate to give a mixture of 9 and pyridine derivative 12. Demethylation of 12 then affords 14. The overall yield for this route was 50%, allowing for conversion of 9 to 12.
Dimroth‐rearranged products in the reactions of 1‐aryl‐2‐methylthiopyrimidinium salts with hydrazines
Authors: Liebscher Jürgen , Hassoun Ahmed , van der Plas Henk , Stam C. 
Published: May 2009

AbstractReaction of 1‐aryl‐2‐methylthiopyrimidinium salts with hydrazine does not lead to substitution at C‐2 but to rearrangement into 1,2‐diaminopyrimidinium salts. An ANRORC‐mechanism involving an azatriene as intermediate is proposed.
Synthesis of novel cyclic sulfone dihydropyridines facilitated by a selective ethyl diazoacetate ring expansion
Authors: Dodd John H. , Schwender Charles F. , Gray‐Nunez Yolanda 
Published: May 2009

AbstractA series of novel cyclic sulfone dihydropyridines with five to nine membered rings have been synthesized. Anomalous intermediates isolated from the Hantzch condensation were found to vary depending on the sulfone ring size and aromatic substitution. Tin tetrachloride has been shown to be a superior Lewis acid catalyst for ethyl diazoacetate ring expansion of the requesite β‐keto cyclic sulfone precursors.
Double 1,3‐dipolar cycloadditions of meso‐ionic heterocycles with N‐phenylmaleimide
Authors: Nan'ya Seiko , Goto Shinya , Butsugan Yasuo 
Published: May 2009

Abstract3‐Phenylsydnone and 2,4‐diphenyl‐3‐methyloxazolium 5‐oxide undergo double 1,3‐dipolar cycloadditions with two molecules of N‐phenylmaleimide to produce 4,8‐iminobenzo[1,2‐c:4,5‐c′]dipyrrole‐1,3,5,7‐tetrone derivatives in a stereoselective manner.
Synthesis of bis‐2,7‐substituted 1,2,3,6,7,8‐hexahydroisoindolo[5,6‐f]isoindole‐1,3,6,8‐tetraones
Authors: Boykin D. W. , Nowak‐Wydra Barbara , Baumstark A. L. 
Published: May 2009

AbstractA series of bis‐2,7‐substituted 1,2,3,6,7,8‐hexahydroisoindolo[5,6‐f]isoindole‐1,3,6,8‐tetraones (naphthalene diimides) has been synthesized. The key intermediate required for synthesis of the naphthalene diimides, 2,3,6,7‐naphthalnetetracarboxylic dianhydride (2) was prepared starting from allene and maleic anhydride. The bis‐anhydride 2 was converted to the naphthalene diimides using conventional methodology by the reaction with amines in organic solvents.
Some new aspects related to the synthesis of meso‐substituted porphyrins
Authors: Gonsalves A. M. d'A Rocha , Varejão Jorge M. T. B. , Pereira Mariette M. 
Published: May 2009

AbstractA general analysis of the steps of the Rothemund reaction, allowed for a better understanding and a significant improvement of this reaction as a synthetic method in some of the previously known difficult syntheses.
The synthesis of novel polycyclic heterocyclic ring systems via photocyclization. 5. [1]Benzothieno[2,3‐c]naphtho[2,1‐f]‐quinoline and [1]benzothieno[2,3‐c]naphtho[1,2‐g]quinoline
Authors: Luo Jiann‐Kuan , Castle Raymond N. 
Published: May 2009

AbstractTwo previously unknown heterocyclic ring systems, namely, [1]benzothieno[2,3‐c]naphtho[2,1‐f]quinoline (4) and [1]benzothieno[2,3‐c]naphtho[1,2‐g]quinoline (5) were synthesized via photocyclization of 3‐chloro‐N‐(2‐phenanthryl)benzo[b]thiophene‐2‐carboxamide (8) followed by chlorination and dechlorination. The total assignment of their 1H‐ and 13C‐nmr spectra was determined by utilizing inverse‐detected HMQC and HMBC two‐dimensional nmr spectroscopic methods.
Fused s‐triazino heterocycles. XVIII. 1,3,4,7,11c‐Pentaazabenz[de]anthracene and 1,3,4,6,7,11c‐hexaazabenz[de]anthracene. Two new ring systems
Authors: Shaw John T. , Thomas Robert J. , Herold Sherry A. , Gfesser Gregory A. , Isovitsch Ralph A. 
Published: May 2009

AbstractThe reaction of 2‐amino‐4‐chloro‐6‐methylpyrimidine (3a) with trimethylacetyl chloride gave 4‐chloro‐6‐methyl‐2‐trimethylacetamidopyrimidine (5). This latter compound with excess anthranilonitrile gave in one step 2‐t‐butyl‐5‐methyl‐1,3,4,7,11c‐pentaazabenz[de]anthracene (6a). To prepare 2‐t‐butyl‐5‐dimethylamino‐1,3,4,6,7,11c‐hexaazabenz[de]anthracene (6b) it was found necessary to first react 2‐amino‐4‐chloro‐6‐dimethylamino‐5‐triazine (3b) with anthranilonitrile to yield the intermediate product 2‐amino‐4(2‐cyanoanilino)‐6‐dimethylamino‐s‐triazine (4). Reaction of the latter with trimethylacetyl chloride gave 6b.
Studies on the constituents of bocconia cordata. IV. Transformation of sanguinarine into bocconine
Authors: Konda Yaeko , Urano Mieko , Harigaya Yoshihiro , Onda Masayuki 
Published: May 2009

AbstractNitration of ethoxysanguinarine with equimolar potassium nitrate and sulfuric acid, followed by treatment with sodium hydroxide and methanol, gives 10‐nitromethoxysanguinarine. Successive hydrogenation, diazotization and methanolysis convert 10‐nitromethoxysanguinarine into bocconine.
Heterocycles. XXVI. A total synthesis of optically pure (+)‐catechin pentaacetate
Authors: Urano Mieko , Kagawa Hitoshi , Harigaya Yoshihiro , Li Shaoshun , Onda Masayuki 
Published: May 2009

AbstractA total synthesis of optically pure (+)‐catechin pentaacetate has been established using the (‐)‐chalcon epoxide (100% ee) derived from 3,4,2′,4′,6′‐pentakis(methoxymethoxy)chalcon as the starting material. The optical purity of the product is confirmed by 1H nmr analysis in the presence of a shift reagent.
A facile synthesis of pyrazole‐5‐sulfonamide derivatives
Authors: Yamamoto Susumu , Sato Toshiaki , Morimoto Katsushi , Makino Kenzi 
Published: May 2009

AbstractThe reaction of the 5‐unsubstituted pyrazoles 2a‐k with lithium diisopropylamide or n‐butyllithium gave intermediary 5‐lithiopyrazoles, whose reaction with sulfur dioxide afforded the lithium pyrazole‐5‐sulfinates 3a‐k. Subsequent reaction of 3a‐k with N‐chlorosuccinimide followed by ammonolysis provided the pyrazole‐5‐sulfonamides 5a‐k.