bluuebunny/crossref_metadata_2025 huggingface dataset:
1‐Alkyl‐4‐aryl‐3,4‐dihydro‐2(1H)‐quinazolinones and thiones. Synthesis and 1H‐NMR spectra
Authors: Houlihan William J. , Cooke George , Denzer Max , Nicoletti Joseph
Published: March 2009

A series of 1‐alkyl‐4‐aryl‐3,4‐dihydro‐2(1H)‐quinazolinones and thiones were prepared by a modification of the Pictet‐Spengler reaction that involves treatment of an N‐alkyl‐N‐arylurea or thiourea with an aryl aldehyde in the presence of methanesulfonic acid. The 1H‐nmr spectra of several of these compounds gave rise to unusual OCH2O and isopropyl signals.
Structure and bonding in 9‐hydroxy‐1,4‐dimethylthioxanthenium bis(carbomethoxy)methylide and related ylides
Authors: Abbady M. A. , Askari S. , Morgan M. , Ternay A. L. , Galloy J. , Watson W. H.
Published: March 2009

The single‐crystal X‐ray structures of 9‐hydroxy‐1,4‐dimethylthioxanthenium bis(carbomethoxy)methylide and 1,4‐oxathianium bis(carbomethoxy)methylide are reported. The methylide carbon of the former is pseudo‐axial while that of the latter is equatorial. The former exhibits a strong intramolecular hydrogen bond to a carbonyl oxygen atom.
Alkylation and an unusual reductive ring opening of some thieno[3,4‐b][1,5]benzoxazepin‐10‐ones
Authors: Olagbemiro Timothy O. , Press Jeffery B.
Published: March 2009

As part of a program towards the syntheses of novel tricyclic compounds, some derivatives of thieno[3,4‐b]‐[1,5]benzoxazepin‐10‐one system 1 were prepared and were subsequently subjected to reduction reactions using lithium aluminum hydride. Although thienobenzoxazines 4 were obtained as the sole product of the reduction in most cases, unusual ring‐opened products, namely 3‐hydroxymethylthiophenes 5, were also formed during several reductions.
Synthesis and structural study of cyclopentane, indene and fluorene spiro‐derivatives
Authors: Galvez E. , Trigo G. G. , Martinez M. , Cabezas N.
Published: March 2009

The synthesis of three pharmacologically interesting series of cyclopentane, indene‐2 and fluorine‐9‐spiro‐5′‐oxazolidine‐2′, 4′‐dione is described. Based on the data from 1H and 13C nmr spectra, the main conformational features of the above mentioned compounds is established.
Zur synthese von 3,4‐dihydro‐2H‐1,4‐benzoxazin‐2‐ und 3‐carbonitrilen. II. Mitteilung über studien zur chemie der 1,4‐oxazine
Authors: Bartsch Herbert , Schwarz Otto
Published: March 2009

Die Reaktion von O‐Aminophenolen mit Dibrompropionsaureestern fiihrt ausschliefilich zu 2‐substituierten Dihydro‐l,4‐benzoxazinen. Die hohe Regioselektivitat wird durch Michael‐Addition der Stickstoffunktion an den durch Bromwasserstoffeliminierung entstandenen Michael‐Acceptor erklart und durch Reaktion von 1a‐1d mit 15, die zu den 2‐Carbonitrilen 16a‐16d fiihrt, bewiesen. Die Substitution der Methoxylgruppe in 18 durch Cyanid liefert das 3‐Carbonitril 19.
Amidrazones. 8. Synthesis of 1,2,4‐oxdiazoles by thermolysis of N3‐acylamidrazone ylides
Authors: Smith Richard F. , Coffman Karen J. , Geer Susan M.
Published: March 2009

N3‐Acylamidrazone ylides 3 were synthesized by the reaction of 2‐(iminophenylmethyl)‐1,1,1‐trimethylhydrazinium hydroxide, inner salt (2a) or 2‐(1‐iminoethyl)‐1,1,1‐trimethylhydrazinium hydroxide, inner salt (2b) with acyl chlorides or acetic anhydride. Thermolysis of 3 gave 3,5‐disubstituted oxadiazoles 4 and trimethylamine.
Structure du méthyl‐3 phénylamino‐4 phényl‐5 triazole‐1,2,4
Authors: Bois Claudette , Philoche‐Levisalles Michéle , Chihaoui Mansour
Published: March 2009

La détermination de la structure du méthyl‐3 phénylamino‐4 phényl‐5 triazole‐1,2,4 a été effectuée par diffraction des RX sur monocristaux. Elle a permis de trancher entre les deux mecanismes de reaction possibles lorsque Ton oppose l'hydrazine à des hydrazonates‐N acylés.
Synthesis of pyrido[3,2‐c]pyridazines
Authors: Turck Alain , Brument Jean‐François , Quéguiner Guy
Published: March 2009

The synthesis of some 3‐methylpyrido[3,2‐c]pyridazines substituted at positions 6 and 6,7 is described. The first step of the preparation of an aza analog of ellipticine is studied.
The reaction of 3‐aminoisoquinoline with nitrous acid
Authors: Schwan Thomas J. , Burch Homer A.
Published: March 2009

The product of the reaction of 3‐aminoisoquinoline and nitrous acid has been identified as the previously unreported 3,4‐isoquinolinedione 4‐oxime hydrate.
Thiocarbamoyl derivatives of N‐acylpiperazines
Authors: Dhawan Balram , Southwick Philip L.
Published: March 2009

1‐(p‐Chlorobenzoyl)piperazine failed to yield a thiocarbamoyl derivative when treated with ammonium thiocyanate; only a thiocyanate salt was formed. However, it reacted readily with benzoylisothiocyanate to form the expected 1‐(N‐benzoylthiocarbamoyl)‐4‐(p‐chlorobenzoyl)piperazine. Benzoylisothiocyanate also produced an N‐benzoylthiocarbamoyl derivative of 1‐formylpiperazine.
Reactions with heterocyclic diazonium salts. Synthesis of several new azolylhydrazones
Authors: Hafez Ebtissam Abdel Aziz , Abed Nosrat Mustafa , Elsakka Ibrahim Ahmed , Elnagdi Mohamed Hilmy
Published: March 2009

Several new stable azolylhydrazones could be synthesized via coupling of diazotised cycliuc amidines with active methylene reagents. The obtained compounds were utilised for synthesis of several, otherwise not readily accessible fused azoles.
Synthesis of 6‐methoxyindoles and indolines. Regioselective c‐6 bromination of indolines and subsequent nucleophilic substitution with a methoxyl group
Authors: Miyake Yuko , Kikugawa Yasuo
Published: March 2009

Regioselective bromination of the 6‐position of indolines was investigated. Treatment of indolines with bromine in sulfuric acid in the presence of silver sulfate or with bromine in superacid afforded the 6‐bromoindolines, which were converted to 6‐methoxyindolines and indoles.
Substituted γ‐lactones. XXX. Reactions of α‐Keto‐β‐Subtituted‐γ‐butyrolactones with diamines
Authors: Amer Adel , Ventura Montserrat , Zimmer Hans
Published: March 2009

The condensation reaction between α‐keto‐β‐aroyl (or acyl) ‐γ‐butyrolactones, 4a‐4e and o‐phenylenediamine or 2, 3‐diaminonaphthalene leads under retrograde aldol condensation involving loss of formaldehyde to formation of 3‐substituted‐3, 4‐dihydro‐2 (1H) quinoxalinones or benzo [g] quinoxalinones, 7a‐7g, respectively as a new convenient synthesis of this type of heterocyclic systems. The reaction of type 4 compound with 4, 5‐diaminopyromidine, 8, was found to proceed differently. 2‐[(4‐Amino‐5‐pyrimidinyl)amine]‐4‐oxo‐3‐(hydroxymethyl)‐4‐phenyl‐2‐butenoic acid 9 was the only product formed when the reaction between 4a and 8 was run in ethanol. The same reaction in glacial acetic acid proceeds with loss of formaldehyde, to afford 7‐phenacylidene‐7,8‐dihydro‐6 (1H)‐pteridione 10. The reaction between type 4 compounds and ethylenediamine or 1, 4‐phenylenediamine leads to the formation of the bis‐condensation products 13–15, respectively.
Synthesis of pyrido [2,1‐f]‐1,3,4‐oxadiazine derivatives
Authors: Molina P. , Ferao A. , Fresneda P. M. , Lorenzo A. , Tárraga A.
Published: March 2009

A convenient synthesis of derivatives of the 4H‐pyrido [2,1‐b]‐1,3,4‐oxadiazine ring system from readily available 1‐amino‐4,6‐diphenyl‐2‐pyridone and phenacyl bromides or arylmethyl ketones is described.
Synthesis of 2‐oxo and 6‐hydroxylated benzimidazole analogs of DOPA as potential norepinephrine antagonists
Authors: Zenker N. , Talaty C. N. , Callery P. S. , Wright J. , Hubbard L. S. , Johnson E. M.
Published: March 2009

The synthesis of benzimidazolone analogs of DOPA and α‐methyl‐DOPA and of the benzimidazole and benzimidazolone analogs of 6‐hydroxy‐DOPA is reported. These compounds showed a moderate amount of dopamine β‐hydroxylase and tyrosine hydroxylase inhibitory activity but did not significantly alter tissue catacholamine levels.
Synthesis of(E)7‐[[2‐[4‐(m‐trifluoromethylphenoxy)‐3α and 3β‐hydroxy‐1‐butenyl]‐5‐oxo‐1 ‐pyrrolidinyl]]heptanoic acids
Authors: Zoretic P. A. , Bhakta C. , Jardin J.
Published: March 2009

The synthesis of an 8‐aza‐PGE1 analog, (E)‐7‐[[2‐[4‐(m‐trifluoromethylphenoxy)‐3α and 3β‐hydroxy‐1‐butenyl]‐5‐oxo‐pyrrolidinyl]]heptanoic acids is reported.
Synthesis of 4,8‐dimethyl‐6‐phenyl‐5,6,7,8‐tetrahydro‐4H‐1,3,6‐dioxazocines
Authors: Nishiyama Tomihiro , Iwasaki Yoshiaki , Yamada Fukiko
Published: March 2009

Five 6‐phenyl‐5,6,7,8‐tetrahydro‐4H‐1,3,6‐dioxazocines were synthesized by the reaction of the corresponding N,N‐bis(2‐hydroxypropyl)‐ and N,N‐bis(2‐hydroxyethyl)chloroanilines with paraformaldehyde in the presence of p‐toluenesulfonic acid.
The synthesis of benzo[b]phenanthro[d]thiophenes and anthra[b]benzo[d]thiophenes
Authors: Tedjamulia Marvin L. , Tominaga Yoshinori , Castle Raymond N. , Lee Milton L.
Published: March 2009

The synthesis of benzo[b]phenanthro[2, 3‐d]thiophene (5), benzo[b]phenanthro[4, 3‐d]thiophene (6), benzo‐[b]phenanthro[2, 1‐d]thiophene (9), benzo[b]phenanthro[3, 2‐d]thiophene (14a), anthra[1, 2‐b]benzo[d]thiophene (24), anthra[2, 3‐b]benzo[d]thiophene (29) and anthra[2, 1‐b]benzo[d]thiophene (30) is described as well as the preparation of 13‐methylbenzo[b]phenanthro[3, 2‐d]thiophene (14b).
Synthesis of (dihydrobenzoxathiinyloxy)acetic acids
Authors: Tegeler John J. , Ong Helen H. , Profitt James A.
Published: March 2009

Several (dihydrobenzoxathiinyloxy)acetic acids have been prepared as potential antihypertensive agents. The dihydrobenzoxathiin ring system was constructed via an intramolecular alkoxide displacement reaction.
Studies on imidazole derivatives and related compounds. 2. Characterization of substituted derivatives of 4‐carbamoylimidazolium‐5‐olate by ultraviolet absorption spectra
Authors: Tarumi Y. , Atsumi T.
Published: March 2009

The representative mono‐ and dialkyl‐substituted derivatives of 4‐carbamoylimidazolium‐5‐olate (1) were synthesized unequivocally. On the basis of their spectral data for ultraviolet absorption spectra in acidic, basic and neutral solutions, we have found some spectral characteristics which make it facile to clarify the position of substituents.
A new synthesis of substituted 2(1H)‐pyrazinones
Authors: Vekemans J. , Pollers‐Wieërs C. , Hoornaert G.
Published: March 2009

The hydrohalides of 2‐sec‐aminoalkanenitriles on treatment with oxalyl halides in o‐dichlorobenzene at 80‐100° give 3, 5‐dihalo‐2(1H)‐pyrazinones, of which the 3‐halo substituent is easily replaced by nucleophiles. A reaction mechanism for the pyrazinone synthesis is proposed.
Effective methods for the syntheses of 2‐pyrazolines and pyrazoles from diazocarbonyl compounds
Authors: Doyle Michael P. , Colsman Mark R. , Dorow Roberta L.
Published: March 2009

Dipolar addition of diazocarbonyl compounds to α,β‐unsaturated esters and nitriles in the presence of pyridine results in the production of 2‐pyrazolines in nearly quantitative yields. In one case, reaction of α‐diazoacetophenone with acrylonitrile, Michael addition of the 2‐pyrazoline to the conjugated olefin is observed, but this process is minimized by limiting the amount of pyridine employed. 5‐Cyano‐2‐pyrazolines are converted to derivative pyrazoles through alkoxide promoted hydrogen cyanide elimination. With vinyl sulfone, α‐diazoacetophenone undergoes sequential dipolar addition, Michael addition, and vinyl sulfite elimination under exceptionally mild conditions to form the derivative β‐(1‐pyrazolyl)ethyl vinyl sulfone in good yield.
4,5,8,9‐tetrahydro‐8‐methyl‐9‐oxothieno[3′,2′:5,6]cyclohepta[1,2‐b]‐ pyrrole‐7‐acetic acid. A new anti‐inflammatory/analgesic agent
Authors: Goudie A. C. , Rosenberg H. E. , Ward R. W.
Published: March 2009

The synthesis of the thienocyclohepta[1, 2‐b]pyrrole acid 1 from the morpholide 3 is reported. This novel morpholide was prepared by regiospecific alkylation of the dianion of 4‐(1, 3‐dioxobutyl)morpholine with 3‐bromomethylthiophene. Subsequent Knorr pyrrole synthesis led to the morpholide 8b which was converted to the desired tricyclic ring system under Vilsmeier conditions. An alternative route involving Friedel‐Crafts cyclisation was used to prepare the related benzocycloheptapyrrole 2.
Réactions entre l'indole et les chlorures d'acides, en milieu basique: Synthèse d'amides de l'ortho [bis(indolyl‐3)]‐2 éthyl, aniline
Authors: Bourgeois Paul , Mesdouze Jean , Philogène Emile
Published: March 2009

Les chlorures d'acides réagissent avec l'indole en milieu aqueux basique et conduisent à des amides secondaires de l'ortho, [bis(indolyl‐3)]‐2 éthyl, aniline. Leur formation peut ětre envisagée comme suit: autocondensation de l'indole pour donner (l'indolyl‐3)‐2 dihydro‐2, 3 indole; acylation de ce composé au niveau de l'azote du cycle saturé; attaque d'une nouvelle molécule d'indole sur le sommet 2 du dérivé formé précédemment acompagnée de l'ouverture du cycle portant la fonction amide.
Synthesis of Benzofuro[3,2‐e][1,4]diazepines
Authors: Gatta Franco , Settimj Guido
Published: March 2009

A synthesis of 4‐N‐oxides and of 3‐hydroxy derivatives of 1,3‐dihydro‐2H‐benzofuro[3,2‐e][1,4]diazepin‐2‐ones and of 2,3‐dihydro‐1H‐benzofuro[3,2‐e][1,4]diazepines is described. Condensation of 2‐acetyl‐ and 2‐benzoyl‐3‐ethoxycarbonylaminobenzofurans with acrylonitrile gave derivatives of 1,2‐dihydro‐ and of 1,2,3,4‐tetrahydrobenzofuro[3,2‐b]pyridine.
Cycloaddition of dimethyl acetylenedicarboxylate to indoles. Isolation of a [2 + 2] adduct
Authors: Augusto J. , Rodriguez R. , Verardo L. I.
Published: March 2009

Thermal reaction of 1,2,3‐trimethylindole (1) and 1,3‐dimethylindole (5) with dimethyl acetylenedicarboxylate in the presence of boron trifluoride etherate gave cyclobutene derivatives 2 and 7 that were isolated for the first time in good yields under themal conditions. In a polar solvent and with an excess of catalyst, 4‐methoxy‐2,4a‐dihydro‐4a,9‐dimethyl‐2‐oxacarbazole 4 was obtained in yields up to 72%.
Synthesis of some alkyl‐ and arylimidazoles
Authors: Watanabe T. , Nishiyama J. , Hirate R. , Uehara K. , Inoue M. , Matsumoto K. , Ohta A.
Published: March 2009

The pyrolysis of 2‐azidopyrazines led to give 1‐cyanoimidazoles, which were hydrolyzed in alkaline and acidic media to the corresponding imidazoles. This ring transformation occurred also by photolysis.
Activated nitriles in heterocyclic synthesis. A novel synthesis of pyrazine derivatives
Authors: Khalifa Mohamed Ali Elsayed , Zayed Ezzat Mohamed , Mohamed Mona Hassan , Elnagdi Mohamed Hilmy
Published: March 2009

A novel synthesis of pyrazine derivatives from the reaction of α‐tosyloximinonitriles with several active methylene enaminonitrile derivatives is reported. The reaction sequence is discussed.
The chemistry of 2H‐3,1‐benzoxazine‐2,4(1H)‐dione (isatoic anhydride). 12. Synthesis of araliopsine and isoplatydesmine
Authors: Coppola Gary M.
Published: March 2009

N‐Methylisatoic anhydride reacts with the lithium enolate derived from 3,3‐dimethyloxiranepropanoic acid ethyl ester (7) to initially produce the acyclic β‐ketoester 8. Under neutral conditions, 8 spontaneously cyclizes to the alkaloid araliopsine (1a). In the presence of acid, 8 cyclizes to a mixture of 1a and its leanear isomer isoplatydesmine (2a).
13C NMR spectral characterization of epimeric rotenone and some related tetrahydrobenzopyranofurobenzopyranones
Authors: Abidi S. L. , Abidi M. S.
Published: March 2009

The 13C nuclear magnetic resonance (nmr) spectra of epimers of rotenone and four 12a‐hydroxy‐analogues were examined to determine the stereochemical effect of the B/C ring fusion involving the 6a‐ and 12a‐carbon centers. Chemical shift differences between the epimeric carbon resonances of cis‐ and trans‐6a,12a‐compounds were notably larger than those of diastereoisomers derived from the same B/C ring junction stereochemistry. Results of the spectral analysis have been useful for the quantification of mixtures of epimers and for the measurement of rates of epimerization and oxygenation.
Synthesis of 1,2,4‐triazoles and 1,2,4‐oxadiazoles
Authors: Lin Yang‐I , Hlavka Joseph J. , Bitha Panayota , Lang S. A.
Published: March 2009

Monothiodiacylamines reacted regiosepecifically with hydrazines and hydroxylamine to give substituted 1,2,4‐triazoles and 1,2,4‐oxadiazoles in excellent yields.
Reaction of 4‐Amino‐1,2,4‐triazines with phosphorus pentasulfide. Deamination during aromatization
Authors: Eid M. M. , Badawy M. A. , Ghazala M. A. H. , Ibrahim Yehia A.
Published: March 2009

Synthesis of several derivatives of thieno[2,3‐e]‐1,2,4‐triazines has been achieved via the action of phosphorus pentasulfide on 6‐vinyl‐ or 6‐acylmethyl‐5‐oxo‐1,2,4‐triazine derivatives. During these investigations interesting synthetically useful functions for phosphorus pentasulfide in pyridine were observed, among which the deamination of certain N‐amino heterocycles is unprecedented.
Chemistry of thienopyridines. XXX. Elaboration of the substituent in 6‐cyanothieno[2,3‐b]pyridine
Authors: Klemm L. H. , Muchiri Daniel R.
Published: March 2009

Ten derivatives of thieno[2,3‐b]pyridine bearing substituents at the 6‐position are obtained from transformations which start with 6‐cyanothieno[2,3‐b]pyridine (2). Treatment of 2 with sodium alkoxide‐alkanol gives imidates (3) in ca. 85% yield. Methyl imidate 3a reacts, in turn, with ammonium chloride to produce a carboxamidine (84%), with 1,ω‐alkyldiamines to form cyclic amidines, and with Meldrum's acid to give an aminoester intermediate (4) (36%). Various reagents then convert 4 into the acetyl derivative (86%) (also obtained directly from 2), an unsaturated aminoester (6) (80%), and a β‐ketoester (7) (39%). Spectral data are reported for these compounds.
Improvement in the synthesis of N,N'‐diacyl‐1,2‐di(4‐pyridyl)ethylenediamines
Authors: Braña M. F. , Castellano J. M. , Rodriguez M. L. López
Published: March 2009

A better synthetic route to pharmacologically active N,N'‐diacyl‐1,2‐di(4‐pyridyl)ethylenediamines is described.
Ester, amide and ether derivatives of 1‐(p‐phenyl‐substituted)‐1,2,3‐triazoles
Authors: Livi Oreste , Biagi Giuliana , Ferrarini Pier Luigi , Primofiore Gianpaolo , Mori Claudio
Published: March 2009

This paper describes the preparation of three series of 1‐phenyl‐1,2,3‐triazol derivatives with an ester, amide or ether group on the phenyl ring. These derivatives were obtained from 4‐hydroxyphenyl‐ and 4‐aminophenyltriazoles, previously synthesized by us, by means of a nucleophilic substitution reaction with acetic anhydride, acyl and alkyl halides. The largest part of compounds were tested in an agricultural chemicals, nutrition and animal health screening programme.
Interaction of alkali metals with unsaturated heterocyclic compounds. The reductive metalation of 1,4‐diphenylphthalazine
Authors: Kaban Seniz
Published: March 2009

1,4‐Diphenylphthalazine (1) was reduced in tetrahydrofuran by sodium metal to a monomeric dianion 2. Chemical reactions of this new dianion were examined with various reagents. Generally, the protonation, acylation and alkylation products were 1,2‐dihydrophthalazine derivatives. An annulation of the phthalazine ring system was accomplished by treating the dianion with 1,3‐dichloropropane or 1,4‐dichlorobutane. With 1,2‐dichloroethane however, only 1,4‐diphenylnaphthalene was detected.
Reaction of 4‐thioxo‐1,3‐benzothiazines with thiocarbohydrazine: Synthesis and reactivity of 1,3,4‐triazolo[3,2‐c]quinazoline derivatives
Authors: Molina P. , Arques A. , Cartagena I. , Valcarcel M. V.
Published: March 2009

2‐Aryl‐4‐thioxo‐1,3‐benzothiazines react with thiocarbohydrazide to give the new mesoionic compounds an‐hydro 1‐amino‐5‐aryl‐2‐mercapto‐1,3,4‐triazolo[3,2‐c]quinazolin‐4‐ium hydroxides. These compounds react with methyl iodide, aldehydes and phenacyl bromides to give 1‐amino‐5‐aryl‐2‐methylthio‐1,3,4‐triazolo‐[3,2‐c]quinazolin‐4‐ium iodides, 4‐arylidenamino‐3‐(o‐aroylamino)phenyl‐1H‐1,2,4‐triazolin‐5‐thiones and 3‐(o‐aroylamino)phenyl‐6‐aryl‐7H‐1,2,4‐triazolo[3,4‐b]‐1,3,4‐thiadiazines, respectively. These latter compounds by sequential treatment with methyl trifluoromethanesulphonate and triethylamine lead to 3‐(o‐aroylamino)‐phenyl‐6‐aryl‐1‐methyl‐7‐mercapto‐1H‐pyrazolo[5,1‐c]‐1,2,4‐triazoles.
Investigation of the reactions of fluorinated isatins and N‐acetylisatins with thiocarbohydrazide: Synthesis of a novel spiro system: 2‐oxo‐1′,2′,4′,5′‐tetrahydrospiro[3H‐indole‐3,3′‐1,2,4,5‐tetrazine]‐6′‐thione
Authors: Joshi Krishna C. , Jain Renuka , Dandia Anshu , Sharma Vandana
Published: March 2009

A novel system 2‐oxo‐1′,2′,4′,5′‐tetrahydrospiro[3H‐indole‐3,3′‐1,2,4,5‐tetrazine]‐6′‐thione has been synthesized by the treatment of fluorinated isatins with thiocarbohydrazide in aqueous ethanolic medium. Under exactly similar conditions, N‐acetylisatin gave exclusively thiocarbohydrazone. The spiro product, on treatment with acetic acid, gave fluorinated isoindigo. Characterization of these products have been done by elemental analyses, ir, pmr and mass spectral studies.
Studies on pyrazines. 13. Chlorination of 1‐hydroxy‐2(1H)‐pyrazinones with phosphoryl chloride. Formation of 2,5‐dichloro‐3‐phenylpyrazine from 1‐hydroxy‐3‐phenyl‐2(1H)‐pyrazinone
Authors: Sato Nobuhiro
Published: March 2009

The chlorination of 1‐hydroxy‐3‐phenyl‐2(1H)‐pyrazinone with phosphoryl chloride proceeded to 5‐chloro‐3‐phenyl‐2(H)‐pyrazinone or 2,5‐dichloro‐3‐phenylpyrazine on heating to elevated temperatures. To define the mechanism of the novel formation, reactions of the parent or methyl‐substituted 1‐hydroxy‐2(1H)‐pyraz‐inones with the same reagent were investigated.
Studies of Some Novel Pyrylium Salts
Authors: Katritzky Alan R. , Sengupta Saumitra , Dinculescu Antonie
Published: March 2009

The preparation is described of some novel pyrylium salts containing ethoxycarbonyl, anthracenyl, and adamantyl substituents.
A short synthesis of praziquantel
Authors: Yuste Francisco , Pallás Yadira , Barrios HÉCtor , Ortíz Benjamín , Sánchez‐Obregón Rubén
Published: March 2009

The synthesis of praziquantel (1), a potent anthelmintic agent, is reported. The synthesis requires five steps and proceeds in 16% yield.
Natural abundance 17O NMR spectroscopy of heteroaromatic Nitro compounds
Authors: Balakrishnan Pattabiraman , Boykin David W.
Published: March 2009

The 17O chemical shift data, at natural abundance, for selected nitroquinolines, nitroindoles, nitroindazoles and nitrothiophenes are reported. In the absence of a peri or a lone‐pair repulsion effect, the nitroquinolines' chemical shifts differ little from those of their carbocyclic analogs. However, the signal for 5‐nitroquinoline, 2, is deshielded by 25 ppm compared to 6‐nitroquinoline, 1, and the 17O nucleus in 8‐nitroquinoline, 3, is deshielded by 49 ppm compared to that in 1. Both these shifts are attributed to rotation of the nitro group from the plane of the heteroaromatic ring arising from peri hydrogen interaction and lone pair repulsion, respectively. The signals for nitro groups on electron excessive ring systems (e.g., indoles and thiophenes) are shielded relative to corresponding ones in electron deficient heterocyclic ring system analogs. The chemical shifts for the π‐excessive systems are interpreted in terms of electronic effects.
Stereo structures and absolute configurations of reaction products of dl‐1,3‐dimethylthymine epoxide with l‐amino acid ethyl esters
Authors: Harayama Takashi , Yanada Reiko , Taga Tooru , Machida Katsunosuke , Yoneda Fumio
Published: March 2009

Each reaction of dl‐1,3‐dimethylthymine epoxide (1) with L‐amino acid ethyl esters (Pro‐OEt, Met‐OEt, Phe‐OEt, and Trp‐OEt) afforded the respective four optically active diastereomers 4–7, stereo structures of which were definitely elucidated as shown in Chart 1 by an X‐ray analysis of 4A and chemical means.
Asymmetric alkaloid synthesis from (S)‐pyroglutamic acid. I. Synthesis of (S)‐5‐ethyl‐2‐pyrrolidinone
Authors: Marco José L.
Published: March 2009

From (S)‐pyroglutamic acid (1) the asymmetric synthesis of (S)‐5‐ethyl‐2‐pyrrolidinone (5) in 30% yield is described.
Réaction d'imidoylation: Réactivité de composés à méthylène actif avec les O‐ethylcarbamates cycliques
Authors: Huché Michel , Lhommet Gérard
Published: March 2009

Les synthèses des α‐(tétrahydroxazole‐1,3 ylidène‐2) et α‐(tétrahydroxazine‐1,3 ylidène‐2) malodinitriles, cyanacétates d'éthyle, et malonates d'isopropylidène sont rapidement réalisées par condensation des malodinitrile, cyanacétate d'éthyle ou malonate d'isopropylidène sur divers O‐éthyl carbamates cycliques.
Studies on biologically active heterocycles. Part I. Synthesis and antifungal activity of some new aroyl hydrazones and 2,5‐disubstituted‐1,3,4‐oxadiazoles
Authors: Dutta M. M. , Goswami B. N. , Kataky J. C. S.
Published: March 2009

A series of new 1‐(2,4‐dichlorobenzoyl) hydrazones and 2‐aryl/aralkyl‐5‐(2,4‐dichlorophenyl)‐1,3,4‐oxadiazoles have been synthesized from 2,4‐dichlorobenzoylhydrazine and different aldehydes. Subsequent ring closure of the substituted aroyl hydrazones yielded the 1,3,4‐oxadiazoles. All the compounds were characterized by their sharp melting point, microanalysis, ir, 1H nmr and mass spectra and screened for their fungitoxic properties against Alternaria tenuis and Curvularia verruciformis. A few of the compounds showed good activity.
Alkyl nitrate nitration of active methylene compounds. Nitration of 2‐substituted 2‐oxazolines
Authors: Feuer Henry , Bevinakatti Hanamanthsa S. , Luo Xuan‐Gan
Published: March 2009

2‐Alkyl‐ and 2‐aralkyl‐2‐oxazolines are readily converted to the corresponding α‐nitroalkyl‐ and α‐nitroaralkyl‐2‐oxazolines on treatment with an alkali metal amide such as potassium or sodium amide in liquid ammonia or with lithium diisopropylamide (LDA) in THF and an alkyl nitrate. Tertiary nitro compounds, such as 2‐(2‐nitro‐2‐propyl)‐4,4‐dimethyl‐2‐oxazoline (16) and 2‐(diphenylnitromethyl)‐4,4‐dimethyl‐2‐oxazoline (17) are obtained in good yield when the anions of 2‐(2‐propyl)‐4,4‐dimethyl‐2‐oxazoline (14) and of 2‐(diphenylmethyl)‐4,4‐dimethyl‐2‐oxazoline (23), generated by LDA are added to the nitrate in THF (inverse addition). The spectral data of the primary and secondary α‐nitroalkyl‐ and α‐nitroaralkyl‐2‐oxazolines reveal that they exist mostly in their dipolar structure. These compounds are readily converted to the corresponding α‐halonitro‐2‐oxazolines on treatment with potassium hypobromite or hypochlorite.
Alkylamination of pteridines by primary alkylamines ‐ potassium permanganate
Authors: Sladowska H. , Van Veldhuizen A. , Van Der Plas H. C.
Published: March 2009

Reaction of 7‐phenyl, 7‐p‐methoxyphenyl, 7‐t‐butyl‐ and 6,7‐diphenylpteridine with ethylamine and t‐butylamine in the presence of potassium permanganate leads to the introduction of the ethylamino or t‐butylamino group at C‐4 in the above‐mentioned pteridines. In the reaction of ethylamine/potassium permanganate besides the 4‐(ethylamino)pteridine derivatives 2‐amino‐3‐formytpyrazines are obtained as side‐products. In the reaction with t‐butylamine/potassium permanganate the corresponding pteridin‐4‐ones are obtained as by‐products. The 1H nmr spectroscopic studies have revealed that at room temperature ethylamine easily gives a σ‐adduct at C‐4, yielding a 4‐(ethylamino)‐3,4‐dihydropteridine derivative. t‐Butylamine, however, only gives with the pteridines addition at C‐4 at low temperature, i.e. at −40°. This adduct dissociates at room temperature. n‐Propylamine and n‐butylamine show the same behavior as ethylamine.
Preparation and reaction of isomeric formyl‐2,1‐benzisoxazoles
Authors: Phillips Brian T. , Hartman George D.
Published: March 2009

The novel 4‐formyl‐2,1‐benzisoxazole and 7‐formyl‐2,1‐benzisoxazole were prepared for conversion via the Hantzsch synthesis to 1,4‐dihydropyridines. The 4‐formyl derivative underwent efficient cyclization to the dihydropyridine while analogous reaction of the 7‐formyl compound has proven problematic.
Synthesis of 4‐aroyl‐5‐nitro‐1H‐imidazoles and 4‐aroyl‐5‐aminoimidazoles
Authors: Albright J. Donald , Moran Daniel B.
Published: March 2009

The reaction of α‐(aryl)‐4‐morpholineacetonitriles (masked aroyl anion equivalents) with N‐protected 4(5)‐bromo‐5(4)‐nitro‐1H‐imidazoles gave 4‐aroyl‐5‐nitroimidazoles which were reduced to afford 4‐aroyl‐5‐aminoimidazoles.
1,3,4‐oxadiazolin‐2‐ones from carbo‐t‐butoxyhydrazones
Authors: Baumgarten Henry E. , Hwang Deng‐Ruey , Rao T. N.
Published: March 2009

5‐Substituted‐1,3,4‐oxadiazolin‐2‐ones 2 were synthesized by the oxidation of carbo‐t‐butoxyhydrazones 1 of aromatic aldehydes with lead tetraacetate or, preferably, iodosobenzene diacetate. In some instances 5‐acetoxy‐1,3,4‐oxadiazoles 3 were obtained along with 2. The oxidation of carboethoxyhydrazones 4 gave 2‐ethoxy‐1,3,4‐oxadiazoles 5.
Synthesis of (imidazo[1,2‐C]pyrimidin‐2‐yl)phenylmethanones and 6‐benzoylpyrrolo[2,3‐D]pyrimidinones
Authors: Danswan Geoffrey , Kennewell Peter D. , Tully W. Roger
Published: March 2009

4‐Pyrimidinamines have been reacted with 3‐bromo‐1‐phenylpropane‐1,2‐dione to give a series of (imidazo[1,2‐c]pyrimidin‐2‐yl)phenylmethanones. The dione also reacted with ethyl amidinoacetate to yield ethyl 2‐amino‐5‐benzoylpyrrole‐2‐carboxylate which was used to prepare a series of 6‐benzoylpyrrolo[2,3‐a]pyrimidines.
Addition‐cyclisations of ethoxycarbonyl isothiocyanate with hydrazine derivatives as a source of thiadiazoles and triazoles
Authors: Kurzer Frederick , Seeker Jane L.
Published: March 2009

Ethoxycarbonyl isothiocyanate reacts additively with hydrazine, ethoxycarbonylhydrazine, as well as amino‐ and 1,2‐diaminoguanidine. Simultaneous or subsequent cyclisation of the resulting 1:1‐ or 2:1‐adducts in acidic or alkaline media yields substituted 1,3,4‐thiadiazoles or 1,2,4‐triazoles, respectively.
Intramolecular dials‐alder cyclization of N‐furfurylpropargylamines: A novel general synthesis of isoindoles
Authors: Katritzky Alan R. , Paluchowska Maria H. , Gallos John K.
Published: March 2009

Benzotriazole mediated synthesis from furfurylamines, aldehydes and lithium acetylides readily provides high yields of N‐furfurylpropargylamines. These undergo intramolecular Diels‐Alder cyclization to give isoin‐doles, which are characterized as their Diels‐Alder reaction products with dimethyl acetylenedicarboxylate.
Synthesis of 2‐acyl‐3‐methylthiofurans from 3‐methylthio‐2‐pentene‐1,5‐dione enolates
Authors: Tinggaard M. , Hansen P. , Mogensen P. K. , Simonsen O. , Becher J.
Published: March 2009

2‐Acyl‐3‐methylthiofurans 3 are obtained in fair yields from 3‐methylthio‐2‐pentene‐1,5‐dione enolates 1 by reaction with iodine. In a similar reaction 1‐phenyl‐3‐methylthio‐4‐nitro‐2‐buten‐1‐one gave 3‐methylthio‐2‐nitro‐5‐phenylfuran 11. In the crystalline state the 2‐benzoyl‐3‐methylthio‐5‐phenylfuran 3b showed a non‐bonded sulfur‐oxygen interaction as inferred from an X‐ray diffraction determination, with a S····O distance of 2.871(5)Å.
Condensed 1,3‐benzothiazinones. 2. Synthesis of 2‐substituted 1,2,4‐triazolo[5,1‐b][1,3]benzothiazin‐9‐ones
Authors: Liu Kang‐Chien , Shih Bi‐Jane , Chern Ji‐Wang
Published: March 2009

Heating 3‐amino‐2‐imino‐3,4‐dihydro‐2H‐1,3‐benzothiazin‐4‐one (1) with formic acid neat or with trimethyl orthoformate (2a) in xylene gave 1,2,4‐triazolo[5,1‐b][1,3]benzothiazin‐9‐one (3a) in 49 and 81% yields, respectively. An analogous reaction of 1 with triethyl orthoacetate (2b) and orthopropionate (2c), trifluoro‐acetic and trichloroacetic anhydride (2d,e), trichloroacetonitrile, dichloroacetyl, chloroacetyl, 2‐chloro‐propionyl, 3‐chloropropionyl, ethoxyoxalyl chloride (2f‐j) and benzoyl chloride (2k) under suitable conditions afforded a series of 2‐substituted 1,2,4‐triazolo[5,1‐b][1,3]benzothiazin‐9‐ones (3b‐k) in 59‐98% yields. Facile procedures for the preparation of 2‐hydroxy and 2‐mercapto derivative 31,m were developed by treating 1 with N,N′‐carbonyl‐ and thiocarbonyldiimidazole (21,m). The structures of all products were assigned on the bases of spectral and elemental analyses. Compound 3m was found to exist predominantly in the 2‐thioxo form.
Synthesis of 1‐hydroxy‐2H,5H‐dihydroisoxazolo[5,4‐c]quinoline. A novel heterocyclic ring system
Authors: Ruhland Béatrice , Leclerc Gérard
Published: March 2009

The synthesis of a new heterocyclic compound, 3a, combining a quinoline and a isoxazolol ring is described. The preparation involves cyclisation of the carbamate 14, followed by concomitant deprotection of the acidic and amino functions to give compound 3a, the stable tautomeric form of 3.
Synthesis of cycl[3.2.2]azine and benzo[g]cycl[3.2.2]azine derivatives by use of the [2 + 8] cycloaddition reaction of indolizines and dimethyl acetylenedicarboxylate
Authors: Tominaga Yoshinori , Shiroshita Yoshihide , Kurokawa Tomohiko , Gotou Hiromi , Matsuda Yoshiro , Hosomi Akira
Published: March 2009

The reaction of 1‐ethoxycarbonylmethylpyridinium bromides 5a‐k with nitro ketene dithioacetal, 1,1‐bis‐(methylthio)‐2‐nitroethylene (2), in the presence of triethylamine in ethanol gave the desired ethyl 2‐methyl‐thioindolizine‐3‐carboxylates 3a‐k in good yields, along with ethyl 2‐methylthio‐1‐nitroindolizine‐3‐carboxyl‐ates 4a‐d. Deesterification of 3 using sodium hydroxide in methanol followed by treatment with polyphosphoric acid gave the corresponding 2‐methylthioindolizines 5a‐d in good yields. The desulfurization of 5 with Raney‐nickel in ethanol occurs smoothly to give the 1,2,3‐unsubstituted indolizines 6a‐c (a, parent indolizine; b, 8‐methylindolzine; c, 6,8‐dimethylindolizine). Similarly, pyrrolo[2,1‐a]isoquinoline (19) was also synthesized.

These indolizine and pyrrolo[1,2‐a]isoquinoline derivatives were allowed to react with dimethyl acetylene to give the corresponding cycl[3.2.2]azine and benzo[g]cycl[3.2.2]azine derivatives in good results.
Preparation and spectroscopic properties of 2‐benzothiazolyl araldehyde hydrazones
Authors: Beam Michael J. , Schulz Jeannette , Sinha Anvita , Collins Pamela , Hallenbeck Susan , Kustin Michael
Published: March 2009

Notwithstanding its tendency toward air oxidation in solution, 2‐hydrazinobenzothiazole I reacted with aromatic aldehydes in ethanol to give the corresponding hydrazones III‐XV in high yields and analytical purity. In related examples, acylation took place under similar conditions to produce hydrazides XVI‐XX. The near‐infrared bands of the absorption spectra of the araldehyde hydrazones have been associated with charge transfer and appeared to correlate with structural elements of the compounds in a way suggesting that the charge transfer was intermolecular.
Synthesis of 2, 2′‐bithienyl derivatives
Authors: Kao Yuh‐Mei , Hwang Wen‐Shu
Published: March 2009

A series of 2, 2′‐bithienyl derivatives were synthesized starting from the coupling of 2, 2′‐bithienyl and 2‐(2‐iodoethyl)‐1, 3‐dioxolane.
Chemistry of the phenoxathiins and isosterically related heterocycles. XXXVII The synthesis and molecular structure of benzo[2, 3]naphtho[5, 6, 7‐ij][1, 4]dithiepin and its 1‐oxide
Authors: Musmar M. J. , Khan Saeed R. , Zektzer Andrew S. , Martin Gary E. , Lynch Vincent M. , Simonsen Stanley H. , Smith Keith
Published: March 2009

Benzo[2, 3]naphtho[5, 6, 7‐ij][1, 4]dithiepin was prepared by the condensation of the disodium salt of 1, 2‐dimercaptobenzene with 1‐chloro‐8‐nitronaphthalene. The structure was established by nmr and mass spectroscopy. A small quantity of benzo[2, 3]naphtha[5, 6, 7,ij][1, 4]dithiepin 1‐oxide was also isolated. The structure was initially established by mass spectrometry. The proton spectrum was totally assigned using a combination of proton zero quantum coherence (ZQCOSY) and proton‐carbon heteronuclear chemical shift correlation (HC‐COSY) techniques, which also allowed the unequivocal assignment of the protonated carbon resonances. An X‐ray crystal structure of the 1‐oxide irrefutably confirmed the structure. The crystal was triclinic and the space group was Pl, and the data refined to a final R = 0.0353. The molecule was shown to be folded about the axis passing through the two sulfur atoms with a dihedral angle of 109.00°.
A new class of non‐classical azapentalenes. Synthesis and c‐13/n‐15 NMR characterization of 2H‐imidazo[1, 5‐d]tetrazoles
Authors: L'Abbé Gerrit , Gelinne Marleen , Toppet Suzanne
Published: March 2009

The title compounds 6 (as well as the oxazoles 5) were obtained by thermolysis of 2‐alkyl‐5‐(methoxycarbon‐yldiazomethyl)tetrazoles 3 in benzonitrile. They were fully characterized by 1H, 13C and 15N nmr spectroscopy.
Michael additions with an enaminoester: Reaction of phenyl 4‐chromone‐3‐sulfonate with methyl 3‐amino‐2‐pentenoate
Authors: Löwe Werner , Kradepohl Anneliese
Published: March 2009

The novel benzoxathiinopyridines 5 and 8 and the hitherto unknown oxathiinobenzopyran 17 were synthesized by ring transformations of phenyl 4‐chromone‐3‐sulfonate (1) with methyl 3‐amino‐2‐pentenoate (2). The structures of 5, 8 and 17 were determined by spectroscopic methods and the reaction pathways for the formation of these compounds are discussed.
Regiospecific synthesis of 2‐methyl‐4‐arylcarbonyl‐2H‐1, 2‐benzothiazin‐3(4H)‐one 1, 1‐dioxides
Authors: Marfat A. , Chambers R. J.
Published: March 2009

Acylation of 2‐methyl‐2H‐1, 2‐benzothiazin‐3(4H)‐one 1, 1‐dioxide 3 with aryl anhydrides in the presence of dimethylaminopyridine occurs regiospecifically to afford 2‐methyl‐4‐arylcarbonyl‐2H1, 2‐benzothiazin‐3(4H)‐one 1, 1‐dioxides 2a‐f.
Nucleophilic addition of 2‐, 3‐, or 4‐[2‐(methylamino)ethyl]pyridine to the aziridine, 7‐methyl‐7‐azabicyclo[4.1.0]heptane
Authors: Rees David C.
Published: March 2009

The synthesis oftrans‐(±)‐N‐methyl‐N‐[2‐[methyl[2‐(3‐pyridyl)ethyl]amino]cyclohexyl]‐4‐benzofuranacetamide dihydrochloride,1which is a 3‐[2‐(methylamino)ethyl]pyridyl derivative of the kappa opioid analgesictrans‐(±)‐N‐methyl‐N‐[2‐(1‐pyrrolidinyl)cyclohexyl]benzofuran‐4‐acetamide monohydrochloride,2is described. The key intermediate istrans‐(±)‐N,N'‐dimethyl‐N‐[2‐(3‐pyridyl)ethyl]‐1,2‐cyclohexanediamine,9which is formed by nucleophilic addition of 3‐[2‐(methylamino)ethyl]pyridine6to the aziridine, 7‐methyl‐7‐azabicyclo[4.1.0]heptane,4. During attempts to prepare the 2‐ or 4‐isomeric pyridyl derivatives of1it was discovered that both 2‐ or 4‐[2‐(methylamino)ethyl]pyridine,5or7are converted toN‐methyl‐N,N‐di‐[2‐(2‐pyridyl)ethylamine]11andN‐methyl‐N,N‐di[2‐(4‐pyridyl)ethylamine]13respectively by refluxing in toluene in the presence of ammonium chloride. The 3‐isomer,6is unchanged after treatment under identical conditions. Careful control of the reaction conditions enabled the aziridine4to be ring opened with the pyridyl amines5or7to give the 1,2‐diaminestrans‐(±)‐N,N′‐dimethyl‐N‐[2‐(2‐pyridyl)ethyl]‐1,2‐cyclohexanediamine,8ortrans‐(±)‐N,N′‐dimethyl‐N‐[2‐(4‐pyridyl)ethyl]‐1,2‐cyclohexane diamine10respectively.
Synthesis and 13C NMR of (trifluoromethyl)hydroxypyrazoles
Authors: Lee Len F. , Schleppnik Francis M. , Schneider Ronald W. , Campbell Dwane H.
Published: March 2009

Reaction of ethyl 4,4,4‐trifluoroacetoacetate with methylhydrazine produced not only the previously reported 5‐hydroxy‐3‐(trifluoromethyl)pyrazole 1 but also its unknown isomer the 3‐hydroxy‐5‐(trifluoromethyl)pyrazole 4. The structure assignments are established based on 13C nmr spectra. Compound 1 was converted to 5‐chloro‐3‐(trifluoromethyl)pyrazolecarboxylic acid 3 in two steps.
Reaction of Cα,O‐dilithiooximes with functionalized carbonyl compounds. Part 2. Reaction with α‐chloroketones and α,β‐unsaturated aldehydes and ketones
Authors: Jarrar Adil A. , Hussein Ahmad Q. , Madi Ahmad S.
Published: March 2009

The reaction of Cα,O‐Dilithiooximes 2 and α‐chloroketones afforded 5‐(hydroxymethyl)‐Δ2‐soxazolines 4. α,β‐Unsaturated aldehydes and ketones reacted with 2 to give the corresponding acyclic 1,2‐addition products 5. The latter were cyclized with phosphorus pentoxide to 5‐vinyl‐Δ2‐isoxazolines 6.
Synthesis of 4,4‐dimethyl‐3,4‐dihydro‐3,3,5‐trisubstituted‐2H‐pyrazoles and N‐benzoyl derivatives: Method for “Hydrolysis” of unreactive amides and carbamates
Authors: Baumstark Alfons L. , Choudhary Anil , Vasquez Pedro C. , Dotrong My
Published: March 2009

Addition of organolithium reagents to 4,4‐dimethyl‐3,5‐disubstituted‐4H‐pyrazoles produced a series of 4,4‐dimethyl‐3,4‐dihydro‐3,3,5‐trisubstituted‐2H‐pyrazoles, 2–6, in good yield. The reaction was stereoselective: addition of organolithium compounds occurred only to carbon‐3 of 4,4‐dimethyl‐3‐alkyl‐5‐aryl‐4H‐pyrazoles. The 3,4‐dihydro‐2H‐pyrazoles were found to be of high sensitivity to oxygen. For long term storage and ease of handling, N‐benzoyl derivatives were synthesized. Removal of the protecting group could not be accomplished by use of many standard sets of conditions. Deprotection was accomplished in high yield by reaction of the N‐benzoyl‐4,4‐dimethyl‐3,4‐dihydro‐3,3,5‐trisubstituted‐2H‐pyrazoles with anhydrous potassium t‐butoxide in toluene [heated under reflux (ultra‐pure argon)] in the presence of a phase transfer catalyst (18‐Crown‐6). Cleavage of a N‐carbamate derivative was also achieved by this phase transfer approach. This methodology should be applicable to the hydrolysis of unreactive amides and carbamates in general.
Synthesis of 3‐substituted‐3,4‐dihydro‐2(1H)‐pyridinones from nitriles
Authors: Chelucci Giorgio , Giacomelli Giampaolo
Published: March 2009

A number of the title compounds have been prepared through a three step reaction sequence based on the cyclization of Δ‐acetal amides.
Effects of substituents on the chlorination of methyl 3‐hydroxythiophene‐2‐carboxylate and on the reaction of the resulting chlorinated products with active hydrogen containing compounds
Authors: Corral Carlos , Lissavetzky Jaime , Manzanares Ignacio
Published: March 2009

The title tandem reactions that produce 5‐substituted compounds of methyl 3‐hydroxythiophene‐2‐carboxylate can also be applied with a minor modification to the 4‐alkyl and 4‐aryl derivatives thereof. On the other hand, 5‐alkyl and 5‐aryl derivatives that undergo a similar smooth chlorination behave in the second reaction in a different manner.
Synthesis and x‐ray crystal structures of isonipecotinamide derivatives as reverse amide analogues of fentanyl
Authors: Borne Ronald F. , Gatchell Catherine L. , Klein Cheryl L. , Harris John , Ellis Portia
Published: March 2009

Several isonipecotinamide derivatives which represent reverse amide derivatives of the potent analgetic agent fentanyl were prepared and evaluated for analgetic activity. The synthetic approaches utilized and stereochemical assignments are discussed. The most potent compound,3, displayed much weaker analgetic activity than fentanyl itself.
A new approach for the synthesis of pteridines: The synthesis of 3‐substituted‐2‐thioxo‐1,2‐dihydro‐4(3H)‐pteridinones
Authors: Urleb Uros , Neidlein Richard , Kramer Walter
Published: March 2009

3‐Substituted‐2‐thioxo‐1,2‐dihydro‐4(3H)‐pteridinones can be conveniently prepared by the reaction of methyl 3‐isothiocyanato‐2‐pyrazinecarboxylate 2 with N‐nucleophiles. The scope and limitations of the method are presented. The tautomeric form of 2‐thioxo‐1,2‐dihydro‐4(3H)pteridinones was determined on the basis of a 13C‐[1H]‐NOE experiment.
A new heterocyclic structure. The 6H‐[1,3]benzoxathiepino[5,4‐d]pyrimidine 5,5‐dioxide
Authors: Löwe Werner , Troll Achim
Published: March 2009

The novel benzoxathiepinopyrimidines 6a‐d were synthesized by ring transformations of 3‐chloromethylsulfonylchromone (2) with amidines 3a‐d.
New synthetic method for 4‐hydroxyproline
Authors: De Martino Giovanni , De Caprariis Paolo , Abignente Enrico , Rimoli Maria Grazia
Published: March 2009

A new synthesis of 4‐hydroxyproline was carried out starting from diethyl p‐nitrobenzoylaminomalonate, which was converted by a three steps pathway into diethyl 4‐hydroxy‐1‐(4‐nitrobenzoyl)pyrrolidine‐2,2‐dicarboxylate, which afforded 4‐hydroxyproline via acid hydrolysis.
Synthesis and reactions of 3‐thioxo[1,2,4]‐triazino[3,2‐b]quinazolin‐10‐ones
Authors: Eid Mohga M. , El‐Zanaty Ali , Ibrahim Yehia A.
Published: March 2009

Thiation of [1,2,4]triazino[3,2‐b]quinazoline‐3,10‐dione 1 proceeds selectively to give the 3‐thioxo‐analog 3. The latter was converted to the corresponding 3‐methylthio derivative 4 which was reacted with aniline and hydrazine to give the corresponding anilino‐ and hydrazino derivatives 5 and 7. Compound 7 was converted to the hydrazones 8a,b and into the novel heterocyclic ring systems [1,2,4]triazolo[4′,3′:4,5][1,2,4]triazino‐[3,2‐b]quinazolin‐7‐ones 9, 10a,b and tetrazolo[1′,5′:4,5][1,2,4]triazino[3,2‐b]quinazolin‐7‐one 11.
A facile synthesis of novel triazoloquinoxahnones and triazinoquinoxalinones
Authors: Rashed Nagwa , El Massry Abdel Moneim , El Ashry El Sayed H. , Amer Adel , Zimmer Hans
Published: March 2009

A series of 1‐aryl‐s‐triazolo[4,3‐a]quinoxalin‐4‐ones, 3, were synthesized via the pyrolysis of the corresponding hydrazones, 6. Thus, the cyclodehydrogenation occurred by refluxing them in an inert solvent (e.g. ethylene glycol) to give the triazoloquinoxalin‐4‐ones in a satisfactory yield. Using DMSO as a solvent for the above transformation afforded as a minor by‐product an S‐ylid. In contrast to earlier findings, annelation of a six‐membered ring was successful and achieved through the pyrolysis of the pyruvate hydrazones derived of the quinoxalin‐4‐ones at −230° to give the as‐triazino[4,3‐a]quinoxalin‐5‐ones, 4. The reaction of 5 with acetylacetone afforded 3‐(3′,5′‐dimethylpyrazol‐1‐yl)‐2(1H)‐quinoxalinone, 10. The structural assignments for the new compounds were based on their elemental analysis and spectroscopic data as well as an independent synthesis.
A Novel synthesis of 6‐hydroxyalkyl‐and 6‐hydroxy‐aralkyl‐6H‐dibenz[c,e][1,2]oxaphosphorin 6‐Oxides
Authors: Yamada Yoichi , Yasuda Heinosuke , Saito Toranosuke
Published: March 2009

A new strategy for the synthesis of 6‐hydroxyalkyl‐ and 6‐hydroxyaralkyl‐6H‐dibenz[c,e][1,2]oxaphosphorin 6‐oxides 3 was achieved by the reaction of 2‐(2‐hydroxyphenyl)phenylphosphonic acid (1) with various carbonyl compounds 2. The desired products 3 were obtained in acceptable yields.
Saturated heterocycles, 162 [1]. synthesis and steric structures of 3,4‐disubstituted 1,6,7,11b‐tetrahydropyrimido[6,1‐a]isoquinolin‐2‐ones
Authors: Fulöp Ferenc , Semega Eva , Bernáth Gábor , Sohár Pál
Published: March 2009

The reaction of 1‐(hydrazidomethyl)‐6,7‐dimethoxy‐1,2,3,4‐tetrahydroisoquinoline 3 with aromatic aldehydes yield hydrazones 4a,b or pyrimido[6,1‐a]isoquinolines 5a‐c depending upon the proportions of the reagents. With ketones, 3 gives only hydrazones 4a‐d and 7, which can be transformed to pyrimidoisoquinolines 10a‐e and 11 with aldehydes. The ring closures are stereospecific; the relative configurations were determined by DNOE measurements.
4,4′‐Coupled bis(isoquinolines)
Authors: Guilani Bardia , Rasco Melvin L. , Hermann Christine F. K. , Gibson Harry W.
Published: March 2009

Reaction of the eneamine 1 formed in situ from isoquinoline and sodium triethylborohydride with aromatic dialdehydes 3 produces 4,4′‐coupled bis(isoquinolines) 4 in good yields. These compounds are readily oxidized with manganese dioxide to the corresponding diketones 5.
Synthesis and stereochemistry of rac.‐trans‐tetrahydro‐6‐hydroxy‐7‐(4‐methoxyphenyl)‐1,4‐thiazepin‐5(2H)‐one
Authors: Mohacsi Erno , O'Brien Jay P. , Todaro Louis J.
Published: March 2009

The base catalyzed reaction of 2‐aminoethanethiol (3) with trans‐3‐(p‐methoxyphenyl)glycidate (4) gave a mixture of isomeric lactams 5 and 6, and in addition, a by‐product 7. The structures of these isomers were proven by X‐ray crystallography. The data revealed that both isomers adopt the chair conformation in the solid state and the size of the heterocyclic ring in compound 5 is a six‐ and in compound 6 is a seven‐membered ring.
1,3‐dipolar cycloaddition as applied to the synthesis of 5‐cyano‐1‐(1,1‐dimethylethyl)‐N‐methyl‐1H‐pyrazole‐4‐carboxamide
Authors: Tao E. V. P. , Rizzo John R. , Aikins James
Published: March 2009

The title compound was synthesized via 1,3‐dipolar cycloaddition of diazoacetonitrile and diethyl fumarate.
Synthesis and regiospecificity in methylation of pyrido[1,2‐a]pyrazinium‐1‐ and 3‐olates and pyrido[1,2‐b]pyridazinium‐2‐ and 4‐olates
Authors: Bátori Sándor , Messmer András
Published: March 2009

New methods have been developed for the synthesis of pyrido[1,2‐a]pyrazinium‐1‐ and 3‐olates 5a‐f, 9 and 1‐thiolate 24 as well as of pyrido[1,2‐b]pyridazinium‐4‐ and 2‐olates 14, 20. The methylation of these new compounds was studied by soft and hard methylating agents. Depending on the nature of the reagent used, the pyrido[1,2‐a]pyrazinium‐1‐olates 5a‐f gave NMe 22a‐f and/or OMe 23a‐f products, whereas the 3‐olate 9 and both the 4‐ and 2‐pyridazinium‐olates 14, 20 afforded solely OMe compounds 10, 15, 21. A selectivity rule for methylation is proposed.