bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemistry of thienopyridines. XXXV. Synthesis, tautomerism, and reactions of quinoline and thienopyridine systems which bear a 1‐carboethoxy‐1‐cyanomethyl substituent in the pyridine ring, part 2
Authors: Klemm L. H. , Lu Jennifer J. , Greene Diana S. , Boisvert William
Published: April 2009

A comparison is made amongst the isosteric Systems quinoline, thieno[2,3,‐b]pyridine, and thieno[3,2‐b]‐pyridine which bear the 1‐carboethoxy‐1‐cyanomethyl substituent (R) alpha or gamma to the heterocyclic nitrogen atom. Treatment of thieno[3,2‐b]pyridine 4‐oxide with ethyl cyanoacetate and acetic anhydride at room temperature (Hamana reaction) gives the alpha R‐derivative 6 (27%), formulated as an intramolecular H‐bonded structure. Neither 6 nor its quinoline alpha analog reacts with refluxing acetic anhydride, while the quinoline gamma isomer 8, existing as NH and CH tautomers, yields an N‐acetyl derivative 10 (70%) under similar conditions. For each of 6 and 8 one can isolate two crystalline forms which differ considerably in color. Compound 10 and its gamma analog in the thieno[2,3‐6]pyridine series (previously obtained directly from a Hamana reaction) serve as acetylating agents for aniline, 1‐aminobutane, morpholine, and cholesterol. Correlations and contrasts in the three Systems are presented.
Regiospecific hydrogenation of quinolines and indoles in the heterocyclic ring
Authors: Shaw J. E. , Stapp P. R.
Published: April 2009

Quinolines, indoles, acridine, and carbazole were hydrogenated using a large variety of heterogeneous catalysts in hydrocarbon solvents in an effort to achieve selective hydrogenation of the heterocyclic ring. When quinolines were hydrogenated using supported platinum, palladium, rhodium, ruthenium, or nickel metal catalysts in the presence of hydrogen sulfide, carbon disulfide, or carbon monoxide, there was exclusive hydrogenation of the heterocyclic ring to give only 1,2,3,4‐tetrahydroquinolines. Use of iridium, rhenium, molybdenum(VI) oxide, tungsten(VI) oxide, chromium(III) oxide, iron(III) oxide, cobalt(II) oxide‐molybdenum(VI) oxide, or copper chromite catalysts also caused exclusive hydrogenation of the heterocyclic ring even without addition of sulfur Compounds or carbon monoxide. Hydrogenation of indoles using platinum, rhenium, or, in some cases, nickel catalysts (with or without sulfur Compounds) occurred exclusively in the heterocyclic ring to give indolines, but conversions were affected by indole‐indoline equilibria.
Unexpected course of the reaction of aromatic aldehydes on lithiated N,N‐dimethyl o‐(3‐quinolyl)carbamate
Authors: Robin Y. , Godard A. , Queguiner G.
Published: April 2009

The reaction of aromatic aldehydes with N,N‐dimethyl O‐(3‐lithioquinolyl)carbamate produces 4‐(dimethyl‐aminomethyl)3‐hydroxyquinolines via a new rearrangement.
Reaction of N,N‐dimethylazidochloromethyleniminium chloride (azidophosgeniminium chloride) with 1,3‐dimethyl‐4‐aminouracils. A new “one pot” synthesis of 3‐aryl‐(and 3‐alkyl)‐4,6‐dimethyl‐5,7‐dioxo‐1,2,3‐triazolo[4,5‐d]pyrimidines (8‐azatheophyllines) via a diazo group transfer process
Authors: Kokel Bruno , Boussouira Nadia
Published: April 2009

N,N‐Dimethylazidochloromethyleniminium chloride (azidophosgeniminium chloride) (1) reacts by diazo group transfer with 1,3‐dimethyl‐4‐aryl‐(and alkyl)aminouracils 4 to give, under mild “one pot” reaction conditions, a very good yield of 3‐aryl‐(and 3‐alkyl)‐4,6‐dimethyl‐5,7‐dioxo‐1,2,3‐triazolo[4,5‐d]pyrimidines (8‐azatheophyllines) 8. That reaction proceeds, very likely, through formation of non‐isolated 4‐imino‐5‐diazouracils 6.
Silica gel assisted reductive cyclization of 2‐nitro‐β‐piperidinostyrenes, derived from 2‐nitrotoluenes, to indoles
Authors: Kawase Masami , Sinhababu Achintya K. , Borchardt Ronald T.
Published: April 2009

An efficient modification of the Leimgruber‐Batcho method of indole synthesis has been devised that facilitates the synthesis of a variety of 2,3‐unsubstituted indoles containing halogen, methoxy and benzyloxy groups, from 2‐nitrotoluenes, in high yields. The modified method involves the condensation of 2‐nitrotoluenes with tripiperidinomethane followed by the reductive cyclization of the intermediate 2‐nitro‐β‐piperidinostyrenes with iron and acetic acid in refluxing toluene in the presence of silica gel (column chromatography grade, 60–200 mesh).
On triazoles. X. The reaction of 5‐amino‐1,2,4‐triazoles with tetrahydrothiophene β‐keto esters
Authors: Esses‐Reiter Klára , Reiter József
Published: April 2009

Three novel ring systems, namely the thieno[3,4‐d]‐1,2,4‐triazolo[1,5‐a]pyrimidine, the thieno[3,4‐e]‐1,2,4‐triazolo[1,5‐a]pyrimidine and the thieno[3,2‐d]‐1,2,4‐triazolo[1,5‐a]pyrimidine were synthesised. The structure of compounds obtained was proved with the help of their uv and cmr spectra using model compounds prepared for this purpose.
The synthesis of [1]benzothieno[2,3‐c]quinolines, [1]benzothieno[2,3‐c][1,2,4]triazolo[4,3‐a]quinoline, and [1]benzothieno[2,3‐c]tetrazolo[1,5‐a]quinoline
Authors: McKenney J. Dew , Castle Raymond N.
Published: April 2009

Photocyclization of 3‐chloro‐N‐phenylbenzo[b]thiophene‐2‐carboxamide 10 afforded [1]benzothieno[2,3‐c]‐quinolin‐6(5H)‐one 11 which was chlorinated to 6‐chloro[1]benzothieno[2,3‐c]quinoline 12 followed by dechlorination to give [1]benzothieno[2,3‐c]quinoline 5. A series of 6‐substituted alkoxy and thioalkoxy[1]benzothieno[2,3‐c]quinoline derivatives were prepared along with the N‐methyl quaternary salt 13 of 5. 6‐Chloro[1]‐benzothieno[2,3‐c]quinoline 12 was converted into 6‐hydrazino[1]benzothieno[2,3‐c]quinoline 23 which upon treatment with formic acid yielded [1]benzothieno[2,3‐c][1,2,4]triazolo[4,3‐a]quinoline 6. Treatment of 23 with nitrous acid resulted in [1]benzothieno[2,3‐c]tetrazolo[1,5‐a]quinoline 7. Compounds 6 and 7 are novel heterocyclic ring systems.
Short syntheses of 1,2,3,5‐tetrahydro‐5‐oxopyrrolo‐[1,2‐a]quinoline‐4‐carboxylic acid and 1,2,3,4‐tetrahydro‐6H‐6‐oxopyrido[1,2‐a]quinoline‐5‐carboxylic acid derivatives
Authors: Chu Daniel T. W. , Claiborne Akiyo K.
Published: April 2009

Short and efficient syntheses of 7‐fluoro‐8‐(4‐methylpiperazin‐1‐yl)‐1,2,3,5‐tetrahydro‐5‐oxopyrrolo[1,2‐a]‐quinoline‐4‐carboxylic acid and 8‐fluoro‐9‐(4‐methylpiperazin‐1‐yl)‐1,2,3,4‐tetrahydro‐6H‐6‐oxopyrido[1,2‐a]‐quinoline‐5‐carboxylic acid are described. Both basic heterocycles were synthesized in two steps by the condensation of a benzoylacetate with an imino ether followed by an intramolecular nucleophilic displacement cyclization reaction.
Synthesis of novel 1,2,3,4‐tetrahydrobenzo[c]‐1,5‐naphthyridines from pyrrolo[1,2‐b]isoquinolines
Authors: Martin Lawrence L. , Scott Susan J. , Setescak Linda L. , Van Engen Donna
Published: April 2009

1,2,3,4‐Tetrahydrobenzo[c]‐1,5‐naphthyridine (5a) was prepared by a novel synthetic route involving the rearrangement of (±)‐(Z)‐1,10a‐dihydropyrrolo[1,2‐b]isoquinoline‐3,10(2H,5H)‐dione oxime to afford 1,4‐dihydrobenzo[c]‐1,5‐naphthyridin‐2(3H)‐one, which was reduced to 5a. The cholinomimetic activity observed with 5a prompted the synthesis and biological evaluation of additional analogues.
The reaction of 6‐halopurines with phenyl metal complexes
Authors: McKenzie Thomas C. , Glass Debbie
Published: April 2009

The reaction of N‐alkyl‐6‐halopurines and phenyl lithium in the presence of various transition metal catalysts was investigated. The 6‐chloro compounds were found to react at C‐8 to give both addition and substitution products. The C‐8 substitution reaction was found to be photo stimulated, and it is likely that it procedes by an electron transfer mechanism. A 6‐iodopurine was found to react with lithium diphenyl cuprate to give 6‐phenylpurine in good yield.
Synthesis and reaction of 6‐substituted 3‐methoxycarbonyl‐4‐methylthio‐2H‐pyran‐2‐one derivatives
Authors: Tominaga Yoshinori , Ushirogochi Atsuyuki , Matsuda Yoshiro
Published: April 2009

Reaction of aryl and styryl methyl ketones1a‐mwith dimethyl bis(methylthio)methylenemalonate (2) in the presence of potassium hydroxide in dimethyl sulfoxide gave the corresponding methyl 6‐aryl‐ and 6‐styryl‐4‐methylthio‐2‐oxo‐2H‐pyran‐3‐carboxylates3a‐m.

6‐Aryl derivatives3a‐d,gwere treated with sodium methoxide in methanol to give the corresponding 6‐aryl‐4‐methoxy‐2H‐pyran‐2‐ones8a‐dand9.Phenylcoumalin (7a) and paracotoin (7b) were synthesized by the desulfurization of 6‐aryl‐4‐methylthio‐2H‐pyran‐2‐ones4a,b.Similarly, anibine (8e) was also synthesized from3g.

Treatment of3with hydrogen peroxide or 3‐chloroperoxybenzoic acid gave the corresponding 4‐methylsulfiny‐2H‐pyran‐2‐ones10a‐fin good yields. Displacement reactions of10a‐fwith nucleophilic reagents are also described.
A facile synthesis of the 1,3‐dithiolo[4,5‐b]pyridine ring system via pyridylthiocyanates
Authors: Chen Ted K. , Flowers William T.
Published: April 2009

2‐Chloro‐3‐thiocyanatopyridine reacted with thioacetic acid and thiobenzoic acid to yield 2‐acetylimino‐1,3‐dithiolo[4,5‐b]pyridine and 2‐benzoylimino‐1,3‐dithiolo[4,5‐b]pyridine respectively. 2,5,6‐Trihalo‐3‐thiocyanatopyridine under the same conditions gave only the corresponding 3‐S‐acetyl‐3‐thio or 3‐S‐benzoyl‐3‐thiopyridine.
Total synthesis of symmetric bile pigments: Mesobilirubin‐IVα, mesobilirubin‐XIIIα and etiobilirubin‐IVγ
Authors: Trull Francesc R. , Franklin Roger W. , Lightner David A.
Published: April 2009

The unnatural bile pigments mesobilirubin‐IVα, mesobilirubin‐XIIIα and etiobilirubin‐IVγ were synthesized following self‐coupling of the pyrromethenones ψ‐xanthobilirubic acid methyl ester, xanthobilirubic acid methyl ester and kryptopyrromethenone, respectively.
The chemistry of polycyclic arene imines. VII. Reactions of phenanthrene 9,10‐imine with aromatic carboxaldehydes, carboxylic acids and acetylenic esters
Authors: Shtelzer Sarah , Sheradsky Tuvia , Blum Jochanan
Published: April 2009

The reactions of phenanthrene 9,10‐imine (1) with aromatic aldehydes, benzoic acids and acetylenedi‐carboxylic esters were investigated. The aldehydes were shown to give 1‐[N‐(arylmethylidene)‐9‐phenanthreneamine‐10‐yl]‐1a,9b‐dihydrophenanthro[9,10‐b]azirine 2. The ‘dimeric’ structure of these products was established by X‐ray diffraction analysis. The carboxylic acids proved to form in the presence of dicyclohexylcarbodiimide, N‐aroylphenanthrene 9,10‐imines 7, that readily undergo rearrangement to N‐aroyl‐9‐phenanthrenamines 8. Esters of acetylenedicarboxylic acid gave the corresponding esters of (Z)‐2‐(1a,9b‐dihydrophenanthro[9,10‐b]azirine‐1‐yl)‐2‐butendioic acid 10.
Synthesis and structure of 6‐ and 7‐(2‐arylvinyl)pteridines
Authors: Abdel‐Hady Sayed A. L. , Badawy Mohamed A. , Kadry Azza M. , Mosselhi Mosselhi A. N.
Published: April 2009

7‐Hydroxy‐6‐styrylpteridine 9 and 7‐(2‐arylvinyl)‐6‐hydroxypteridines 10–12 were synthesized via the condensation of 5,6‐diaminouracil 1 with benzylidenepyruvic acids 2–4. The synthesis of the 2‐methylthio analogue 15 is also described.
An improved synthesis of 3‐(1‐imidazolyl)‐2‐alkenoic acid derivatives and related compounds
Authors: Kashima Choji , Yoshiwara Nobutoshi , Tajima Tadakuni , Omote Yoshimori
Published: April 2009

The preparative method of 3‐(1‐imidazolyl)‐2‐alkenoic acid derivatives and the related compounds was improved by the use of strong bases such as sodium hydride in DMF. By this improved method, the preparation of 2‐substituted 3‐(1‐imidazolyl)‐2‐alkenoic acid derivatives was accomplished in good yields.
Synthesis and antifungal activity of some allylamine derivatives
Authors: Bandiera Tiziano , Albini Franca Marinone , Albini Enrico
Published: April 2009

Benzo‐ and mesitonitrile oxides react with allylamine to yield 5‐aminomethyl‐2‐isoxazolines and open‐chain N‐substituted amidoximes. The allylamine derivatives were evaluated as potential antifungal and antibacterial agents. The N‐allylbenzamidoxime 2a was found to be only moderately active against dermatophytes.
Reactions with 2‐mercaptopyrimidines. Synthesis of some new thiazolo[3,2‐a]‐ and triazolo[4,3‐a]pyrimidines
Authors: Hussain S. M. , El‐Reedy A. M. , Rezk A. M. Hassan , El‐Dien Kh. A. Sife
Published: April 2009

Alkylation of 5‐cyano‐4‐oxo‐6‐phenyl‐2‐thioxo‐1,2,3,4‐tetrahydropyrimidine I with methyl iodide, chloroacetic acid or 3‐chloro‐2,4‐pentanedione, afforded the S‐alkyl derivatives IIa‐c. 2‐Carboxymethylthio and 2‐(2′,4′‐dioxopentan‐3‐ylthio) derivatives IIb and IIc could be cyclised by acetic anhydride or polyphosphoric acid to give 6‐cyano‐3,5‐dioxo‐5H‐7‐phenylthiazolo[3,2‐a]pyrimidine III and 2‐acetyl‐6‐carboxamido‐5H‐3‐methyl‐7‐phenylthiazolo[3,2‐a]pyrimidine‐5‐one IX, respectively. Benzoylation of 2‐hydrazinopyrimidine derivative XII, in anhydrous dioxan, afforded the N‐benzoyl derivative XIII, which could be cyclised by heating in dimethylformamide to give 5‐amino‐6‐cyano‐3,7‐diphenyl‐s‐triazolo[4,3‐a]pyrimidine (XIV). The 2‐hydrazinopyrimidine derivatives XII and XV reacted with benzoyl isothiocyanate in dioxane to yield 4‐benzoylthiosemicarbazide derivatives XVI and XVII, which were converted into the 2‐s‐trizolopyrimidine derivatives XVIII and XIX, respectively. Also, XVI and XVII reacted with 2,4‐pentanedione and 3‐chloro‐2,4‐pentanedione to yield 2‐pyrazolopyrimidine derivatives XX and XXI, respectively.
The synthesis of some 2,4‐disubstituted derivatives of quinolone‐3‐carboxylic acids and carbonitriles
Authors: Leysen D. L. , Haemers A. , Bollaert W. , Dommisse R. A. , Esmans E. L.
Published: April 2009

In order to prepare the 2‐chloro derivative of oxolinic acid, ethyl 1‐ethyl‐1,4‐dihydro‐2‐hydroxy‐6,7‐methylenedioxy‐4‐oxo‐3‐quinolinecarboxylate was treated with phosphorus oxychloride. The compound obtained was the 4‐chloro‐2‐oxo‐quinoline. The structure was confirmed by 13C nmr and mass spectral techniques. The 2‐halocarbonitrile was obtained by a Sandmeyer reaction but could not be hydrolysed into the acid.
Synthèse et étude structurale de dérivés substitués en ‐2 du thiazolidine carboxylate d'éthyle‐4 (R)
Authors: Hamri Abdesselam , Péra Marie‐Hélène , Fillion Houda
Published: April 2009

Des dérivés de la thiazolidine carboxylate d'éthyle‐4(R) sont obtenus sous la forme d'un mélange de diastéréoisomères dont le pourcentage est modifié par addition d'acide trifluoroacétique.
P‐N compounds. 30. Phosphaminimides. 5. N‐phosphinylimino‐1,2,5,6‐tetrahydropyridines
Authors: Cates Lindley A. , Li Ven‐Shun
Published: April 2009

N‐[ (Diethoxyphosphinyl)imino] and N‐[ (diphenylphosphinyl)imino]‐5‐methyl‐1,2,5,6‐tetrahydropyridines were prepared by sodium borohydride reduction of the corresponding pyridinium and 3‐methyl pyridinium inner salts. The carbonyl analog of this latter precusor was resynthesized and its structure completely verified.
A facile retro‐ene reaction of 5‐(methoxyamino)‐3‐aryl‐1,3,4‐oxadiazol‐2(3H)‐ones
Authors: Kleier Daniel A. , Pilgram Kurt H.
Published: April 2009

5‐(N‐Methoxy‐N‐methyl)amino‐3‐aryl‐1,3,4‐oxadiazol‐2(3H)‐ones3undergo a heteroretro‐ene reaction in refluxing methanol in which the leaving enophile is formaldehyde. The resulting 5‐(methylimino)‐3‐aryl‐1,3,4‐oxadiazolidin‐2‐one4may be viewed as a kinetic product which tautomerizes to the more stable 5‐(methylamino)‐3‐aryl‐1,3,4‐oxadiazol‐2(3H)‐one5as the thermodynamic product. Comparison of calculated reaction energies reveals that the presence of the heterocyclic ring facilitates the retro‐ene reaction, but the expulsion of formaldehyde is predicted to be highly exothermic even in its absence.
On the nitro group transfer from 2‐nitro‐4,5,6,7‐tetrachloro‐2H‐benzotriazole and 2‐nitro‐2H‐phenanthro[9,10‐d]triazole to secondary amines
Authors: Cohen‐Fernandes Pauline , Habraken Clarisse L.
Published: April 2009

The synthesis of 2‐nitro‐4,5,6,7‐tetrachloro‐2H‐benzotriazole 1 and of 2‐nitro‐2H‐phenanthro[9,10‐d]‐triazole 2 and their transfer of the nitro group to give 1‐nitropyrrolidine 4a and 1‐nitromorpholine 4b in high yields when reacted with pyrrolidine or morpholine are reported. The reaction of 1 also gives the pyrrolidinium and morpholinium salts 5a‐b of 1.
Chemistry of C‐heteroarylnitrilimines. Synthesis and cycloaddition reactions of N‐phenyl‐C‐(2‐thienyl)nitrilimine
Authors: Hassaneen Hamdi M. , Mousa Hiyam A. H. , Shawali Ahmad S.
Published: April 2009

The nitrilimine 7, generated in situ from N‐phenyl‐C‐(2‐thienyl)formohydrazidoyl chloride 5 in chloroform in the presence of triethylamine, reacts with acrylonitrile, acrylamide and arylidene acetophenones to give exclusively the 5‐substituted 2‐pyrazoline derivatives 9, 10 and 16, respectively. On the other hand, the cycloaddition of 7 to coumarin, benzalmalononitrile and the enolate anions of active methylene compounds yield the pyrazole derivatives 12, 14 and 23, respectively. The structures of the cycloadducts prepared were attributed on the basis of spectroscopic and chemical evidence. The regioselectivity in the studied reactions is discussed in terms of the frontier orbital theory.
Synthesis of 2,4‐(1H,3H)‐quinazolinediones
Authors: Hammen Philip D. , Allen Douglas J. M.
Published: April 2009

Improved procedures for syntheses of kilogram quantities of quinazolinedione 5 and its intermediates 2,3 and 4 are described. The mechanism of formation of 5 is discussed as well as a side reaction resulting in 7.
Synthesis of 3‐benzoyl‐3,4‐dihydro‐2H‐ and 3,4‐dihydro‐2,2‐disubstituted‐benzopyrans via alkynyl grignard reagents
Authors: Adegoke Emmanuel A. , Emokpae T. A. , Ephraim‐Bassey H. , Oyelola C. A.
Published: April 2009

The versatility of the new route to a substituted chromane via a lithiated allene recently described by us [1] is reported. The relatively more stable alkynols 2–4 were readily identified and thus provide evidence for the formation of vinyl acetylene carbinol as an intermediate in the new route. Accordingly, phenylacetylene magnesium bromide [2] reacted with suitable aldehyde or ketone to give the alkynols 2–4 which condensed further with the same or different aldehyde or ketone to give 3‐benzoyl heteroring‐substituted chromanes 5–17.
Reaction of 5‐hydroxy‐L‐tryptophan with alkyl isocyanates
Authors: Braña Miguel F. , Garrido Mercedes , Hernando José L. , Rodríguez María L. LÓPez , Morcillo M. José
Published: April 2009

5‐Hydroxy‐L‐tryptophan 4 with potassium cyanate gives 5‐(5‐hydroxy‐3‐indolylmethyl)hydantoin 5 or Nb‐carbamoyl‐5‐hydroxy‐L‐tryptophan 6 depending on the reaction conditions. Reaction of 4 with methyl iso‐cyanate in acetone provides 5‐hydroxy‐Nb‐methylcarbamoyl‐L‐tryptophan 7. Treatment of 4 with ethyl, propyl and isopropyl isocyanates in acetone gives rise to the formation of the corresponding 2‐[(3‐alkyl‐4,4‐dimethyl‐2‐oxo)‐1,3‐diazetidinyl]‐3‐(5‐hydroxy‐3‐indolyl)propionic acids 8–10.
Reversible formation of cyclic 1,4‐benzothiazine oligomers
Authors: Chioccara Francesco , Novellino Ettore
Published: April 2009

1,4‐Benzothiazine 2, generated in situ by mild hydrolysis of aminoacetal 3, readily undergoes aldolization to give mainly two pairs of diastereoisomeric trimers and tetramers, having the gross structure 5 and 6 respectively. In strongly acidic media the oligomers are depolymerized to give monomeric 2H‐1,4‐benzothiazine (1H nmr evidence) which, at slightly acidic or neutral pH, is converted to a mixture of the same trimers and tetramers. These results provide an improved background to look into the biosynthesis of phaeomelanins which are known to originate by polymerization of 1,4‐benzothiazine intermediates.
Cyclization of diketones to pyridazine and furan derivatives
Authors: Allah Hassan M. Faid , Soliman Raafat
Published: April 2009

Condensation of (±)‐2,3‐bis(3,4‐dimethoxybenzoyl)butane‐1,4‐dione 1 with different hydrazine bases afforded the corresponding pyridazines 2 and 3. Refluxing the diketone 1 with methanolic hydrogen chloride yielded the corresponding 3,4‐dimethylfuran derivative 5. Reaction of acetonylacetone 6 with p‐sulfamylphenylhydrazine afforded the corresponding 3,6‐dimethyl‐1H‐pyridazine derivative 7. Reaction of 7 with the appropriate isocyanate and isothiocyanate yielded the corresponding benzenesulfonylurea 8 and thiourea 9 derivatives respectively. The structures of the compounds synthesized were affirmed by microanalyses and spectral studies.
Reaction of t‐butyl lithium with (±)‐3‐methoxy‐N‐chloromorphinan
Authors: Mohacsi Erno , Yang Roxana , Blount John
Published: April 2009

Preparation of (±)‐3‐methoxy‐16‐t‐butylmorphinan (4) by reaction of t‐butyl lithium with (±)‐3‐methoxy‐N‐chloromorphinan (1) is described. The structure of 4 was confirmed by X‐ray crystallography.
Thiazolidinethiones vs. imidazolidinedithiones as products from cyanothioformanilides and phenyl isothiocyanates
Authors: Huang Jamin , Graves Michael D.
Published: April 2009

The formation of thiazolidinethiones 3 and/or imidazolidinedithiones 5 from cyanothioformanilides and aryl isothiocyanates is found to be dependent upon the type of bases used, reaction temperature and the nature and position of substituents on cyanothioformanilides. Examples are presented.
Studies in the furan series. 23. Preparation of some new 5‐substituted furfurylallylarylamines. Influence of substituents on the intramolecular Diels‐Alder (IMDA) reaction
Authors: Klepo Ž. , Jakopčić K.
Published: April 2009

Several new N‐allyl‐N‐(5‐substituted)‐2‐furfuryl‐p)‐toluidines IIIa‐e with Cl, Br, I, NO2 or CH3O groups in position 5 of the furan nucleus were prepared by allylation of the corresponding secondary furfurylaryl‐amines. Both, electron withdrawing and releasing substituents enhanced the yield of intramolecular [4+2] cycloaddition.
Synthesis of arylsulfonyl substituted pyrroles
Authors: Dalla Croce Piero , Gariboldi Pierluigi , La Rosa Concetta
Published: April 2009

The cycloaddition reaction of symmetrically and unsymmetrically substituted munchnones with arylsulfonyl alkynes has been studied. The reaction affords pyrrole derivatives whose structures were assigned on the basis of spectroscopic data. The distribution of regioisomers observed in the case of unsymmetrically substituted munchnones is discussed.
Pyrrole reduction: The zinc/acid reduction of octahydrocarbazoles
Authors: Anderson‐McKay Janet E. , Lawlor John M.
Published: April 2009

The stereo‐ and regiochemical course of the zinc/acid reduction of 1,2,3,4,5,6,7,8,‐octahydrocarbazole is strongly influenced by experimental conditions and by the nature of the N‐substituent.
Transformations of N‐heteroarylformamidines into derivatives of β‐heteroarylamino‐α,β‐dehydro‐α‐amino acids, β‐heteroarylamino‐α‐amino acids, and dipeptides
Authors: Stanovnik Branko , Svete Jurij , Tišler Miha
Published: April 2009

Transformations of N'‐heteroaryl‐N,N‐dimethylformamidines 1 as a general method for the preparation of β‐heteroarylamino‐α,β‐dehydro‐α‐amino acids, β‐heteroarylamino‐α‐amino acid derivatives 5–9, and dipeptides 10, are described.
Synthetically attractive indolization processes and newer methods for the preparation of selectively substituted indoles
Authors: Pindur Ulf , Adam Reinhard
Published: April 2009

The synthetically interesting processes available for indolization reactions are discussed and illustrated in tabular form and particular emphasis is placed on the more recent methods.
A conformational analysis of the six isomers of bipyridinium dication
Authors: Von Nagy‐Felsobuki Ellak I.
Published: April 2009

The conformational analysis of the bipyridinium dications have been investigated using ab initio STO‐3G calculations in which the inter‐ring bond length was optimized at each torsional angle. The variation of the inter‐ring separation has been rationalized using a heuristic valence bond model (which is electrostatic in nature) and which was suggested by the molecular orbital calculations. Furthermore, all six isomers show a double potential minima at the optimium torsional angles of ∼ 50° and ∼ 130° respectively. Moreover, all barrier heights are calculated to be less than 8 kJ mol−1, thereby suggesting that the barrier heights are not large enough to prevent rapid interconversion between different rotamers.
Studies on pyrrolidinones. Synthesis of N‐acylpyroglutamic acids having bactericide and fungicide properties
Authors: Rigo Benoǐt , Lespagnol Charles , Pauly Marc
Published: April 2009

The best method to prepare N‐acylpyroglutamic acids is to react N,O‐bistrimethylsilylpyroglutamic acid with acid chlorides or a diketene. These acyl acids display bactericide and fungicide properties against several microorganisms.
Temperature and solvent effects on the experimental dipole moments of three crown ethers
Authors: Caswell Lyman R. , Savannunt Diana S.
Published: April 2009

Dipole moments of 12‐crown‐4, 15‐crown‐5 and 18‐crown‐6 have been measured for solutions in benzene and in cyclohexane at 15, 20, 25, and 30°, using the Guggenheim‐Smith method. The dipole moments of the more common conformers of these crown ethers have also been calculated. The results indicate that these crown ethers exist in solution as mixtures of conformers. The conformational equilibria shift toward the more polar conformers as temperature increases. There is evidence that the more polar conformers of 12‐crown‐4 and 15‐crown‐5 are somewhat more favored in benzene solution than in cyclohexane, possibly as the result of a weak complexation with the former solvent.
Directed lithiation of 4‐halopyridines: Chemoselectivity, regioselectivity and application to synthesis
Authors: Marsais F. , Trécourt F. , Bréant P. , Quéguiner G.
Published: April 2009

4‐Chloro and 4‐fluoropyridines were ortho‐lithiated by n‐butyllithium‐TMEDA chelate or lithium diiso‐propylamide at low temperature. The resulting 3‐lithio 4‐halopyridines were reacted with electrophiles which led to various 3,4‐disubstituted pyridines. The versatility of this functionalization is enhanced by the 4‐halogen reactivity towards nucleophiles such as water, methylate and amines. Some of the 3,4‐disubstituted synthons were annelated to naphthyridine, xanthone and coumarin or condensed to Hantsch‐ester or to “chlotrimazol” analogues. Lithiation of 4‐fluoropyridine led in one step to 3,4‐pyridyne, which was trapped by cycloaddition with furans.
Angular heterocycles. A convenient synthesis of azabenzophenothiazines
Authors: Kang W. B. , Nan'ya Seiko , Maekawa Eturǒ , Ueno Yoshio
Published: April 2009

The acid‐catalysed reaction of substituted 1,4‐naphthoquinones with o‐aminoheterocyclic thiones in alcoholic solution afforded substituted monoazabenzo[a]phenothiazin‐5‐ones 4,5 and substituted benzo[a][1,4]diazabenzothiazino[3,2‐c]phenothiazin‐5‐one (6). Some of the resulting compounds were subjected to dehalogenation. The structures of the products were assigned by elemental analysis, 1H‐nmr, and other spectral analysis.
Pyridazines. XXXV. Preparation of some novel pyrimido[4,5‐c]pyridazine derivatives from 3‐alkylamino‐ and 3‐arylamino‐4‐pyridazinecarboxamides
Authors: Haider Norbert , Heinisch Gottfried , Laßnigg Doris
Published: April 2009

Facile syntheses of pyrimido[4,5‐c]pyridazine‐5,7(6H,8H)diones 4, pyrimido[4,5‐c]pyridazin‐5(8H)‐ones 7–10, and dihydropyrimido[4,5‐c]pyridazin‐5(6H)ones 5,6 starting from 3‐chloro‐4‐pyridazinecarbonitrile 1 via aminocarbonitriles 2 and aminocarboxamides 3 are described. In addition, a convenient access to the new aminopyridazinecarbonitrile 11 from the chloronitrile 1, employing the tetrazolo[1,5‐b]pyridazine 12 as the key intermediate, is reported.
A hantzsch 1,4‐dihydropyridine synthesis producing an unusual by‐product
Authors: Patterson J. W. , Nelson J. T.
Published: April 2009

The reaction of 2‐acetyl‐1‐(2‐chlorophenyl)‐6‐methylhept‐1‐en‐3‐one (2) with ethyl 3‐aminocrotonate gave an unusual isomer of a 1,4‐dihydropyridine (6), having an exocyclic double bond. The structure and stereochemistry of 6 was established with 1H and 13C nmr spectroscopy.
Selective instability of trifluoromethyl linked to carbon. A prerequisite for new heterocyclizations with ethyl 4,4,4‐trifluoroacetoacetate arylhydrazones
Authors: Pilgram Kurt H. , Skiles Richard D.
Published: April 2009

Highly functionalized pyrazoles, 2, and 1H‐pyrazolo[3,4‐d]pyridazinones 3 have been obtained in moderate yields from ethyl 4,4,4‐trifluoroacetoacetate o‐chlorophenylhydrazones 1 by treatment with sodium hydride in aprotic solvents. Treatment of 2 and 3 with sodium ethoxide in ethanol gave bicyclic 5‐(5‐oxopyrazol‐3‐yl)‐pyrazolones 4 and 5 in high yields. The reactions of 1 with sodium hydride which are accompanied by the loss of fluoride ion from one trifluoromethyl group implicate the anchimeric assistance of an N‐deprotonated anion of 1 in the initial reaction step.
Synthesis, characterization and electron impact mass spectrometry of Schiff bases rearranging to oxazoline, thiazoline and thiazole derivatives
Authors: Guerriero Paolo , Bullita Elvio , Vigato Pietro A. , Pelli Beatrice , Traldi Pietro
Published: April 2009

A series of oxazoline compounds have been prepared by reaction of 2,6‐diformyl‐4‐chlorophenol, 2,6‐diformylpyridine or 2,5‐diformylthiophen with o‐aminophenol or o‐aminothiophenol respectively. The oxazoline derivatives are stable both in solid state and in solution while the thiazoline derivatives easily oxidize to the corresponding thiazoles. Physico‐chemical data confirm this oxidation process. The 70 eV electron impact induced decomposition pathways of these compounds, obtained with the aid of exact mass measurements, B/E linked scans and collisional spectroscopy, are discussed in detail.
The 13C NMR of monochlorocarbazoles, monochlorotetrahydrocarbazoles and their 9‐methyl derivatives
Authors: Dodsworth David J. , Quesada P. Andres , De Rosa Michael
Published: April 2009

The 13C nmr of monochlorocarbazoles, monochlorotetrahydrocarbazoles and their 9‐methyl derivatives were measured and the chlorine effects at the ipso, ortho, meta, and para carbons determined.
On Triazoles. XIII. The reaction of 5‐benzalimino‐1,2,4‐triazoles with substituted acetyl chlorides
Authors: Reiter József , Pongó László , Sohár Pál , Dvortsák Péter
Published: April 2009

The reaction of Schiff bases prepared from 1‐ and 2‐substituted‐5‐amino‐1,2,4‐triazoles with phenoxyacetyl chlorides in the presence of triethylamine and a mixture of phosphorus oxychloride and dichloroacetic acid in dimethylformamide to yield β‐lactam 4, a dihydro‐1,2,4‐triazolo[4,3‐a]pyrimidine‐5(1H)‐one 5, a 1,2,4‐triazolo[1,5‐a]pyrimidin‐5(3H)‐one 9 and the corresponding 1,2,4‐triazolo[4,3‐a]pyrimidine‐5(1H)‐one 10 derivatives was studied.
Synthesis of 2‐nitro‐L‐tryptophan
Authors: Phillips Robert S. , Cohen Louis A.
Published: April 2009

Nitration of N‐(trifluoroacetyl)‐L‐tryptophan methyl ester provides 40% of the anticipated 6‐nitro product and 6–7% of the novel 2‐nitro derivative. The latter compound is deprotected with aqueous acid to form 2‐nitro‐L‐tryptophan. Analogous nitration of L‐tryptophan gives only the 6‐nitro product.
A one‐step preparation of pyrido[3,4‐d]pyrimidine ring system by reaction of 5‐formyl‐1,3,6‐trimethyl‐pyrimidine‐2,4(1H,3H)‐dione with primary amines
Authors: Noguchi Michihiko , Sakamoto Kazushige , Nagata Seiji , Kajigaeshi Shoji
Published: April 2009

6,7‐Dihydropyrido[3,4‐d]pyrimidine‐2,4(1H,3H)‐diones were obtained in high yields from the reaction of 5‐formyl‐1,3,6‐trimethylpyrimidine‐2,4(1H,3H)‐dione (1) and primary amines. For this pyridopyrimidine synthesis the following reaction pathway is proposed; the [1,5]‐hydrogen shift of 1 gives a 5,6‐dihydro‐5,6‐dimethylenepyrimidine‐2,4(1H,3H)‐dione intermediate. The cycloaddition reaction of the intermediate with aldimines from 1 and the primary amines affords 5,6,7,8‐tetrahydropyrido[3,4‐d]pyrimidine‐2,4(1H,3H)‐diones, which are dehydrated to the final products.
Electron impact mass spectrometry of some 2‐(p‐bromophenyl)‐4,4‐disubstituted‐5(4H)‐oxazolones
Authors: Crisma Marco , Pelli Beatrice , Traldi Pietro
Published: April 2009

The mass spectrometric behaviour of four 2‐(p‐bromophenyl)‐4,4‐disubstituted‐5(4H)‐oxazolones has been investigated using linked scans, mass analyzed ion kinetic energy spectrometry, accurate mass measurements and collisional spectroscopy. The study shows the formation of similar ions in all cases, with the presence of skeletal rearrangements, leading to highly stable product ions.
Pyrido[2,3‐d]pyrimidines and pyrido[2,3‐d; 5‐d′]dipyrimidines as potential chemotherapeutic agents.VIII
Authors: Ram Vishnu J. , Vanden Berghe D. A. , Vlietinck A. J.
Published: April 2009

Reactions of 5‐dimethylaminomethylene‐6‐imino‐1,3‐dimethyluracil hydrochloride (1) with active methylene compounds2and4yielded bi‐ and tricyclic heterocyclic compounds3and5. All the prepared compounds were screened for chemotherapeutical activities but none were active.
Mass spectral fragmentation patterns of 2,3‐diphenylindole derivatives and dibenzo[ac]carbazoles
Authors: Erra‐Balsells Rosa
Published: April 2009

The electron impact mass spectra of a variety of substituted 2,3‐diphenylindoles have been examined and the major fragmentation routes ascertained. The mass spectra of several dibenzo[ac]carbazoles are also discussed. All of the results allow us to assume that 2,3‐diphenylindoles would not cyclize in the spectrometer upon electron impact.
Synthesis and spectroscopic properties of N‐azolylpropanamides
Authors: De La Cruz Angeles , Elguero Jose , Goya Pilar , Martinez Ana
Published: April 2009

Fourteen N‐azolylpropanamides have been prepared by Michael addition of azoles on acrylamide. The compounds have been fully characterized by IR and by 1H and 13C‐nmr. The isolated compounds are the most stable derivatives; kinetic compounds were observed but could not be isolated.
Synthesis of 4‐acyl‐and 235 4‐alkenyl‐3,5‐dimethylisothiazole derivatives
Authors: Alberola Angel , Alonso Felisa , Cuadrado Purificación , Sañudo María Carmen
Published: April 2009

4‐Acyl‐ and 4‐alkenyl‐3,5‐dimethylisothiazole derivatives, not available by direct electrophilic substitution [1–5] have been prepared from 3,5‐dimethyl‐4‐isothiazolylcarbonitrile 1 and the corresponding aldehyde 2 in satisfactory yields. Both compounds, 1 and 2, are readily obtained from 3,5‐dimethyl‐4‐iodoisothiazole, whose preparation we have previously reported [6].
New synthesis of pyrido[2,3‐d]pyrimidines. III. Nucleophilic substitution on 4‐amino‐2‐halo and 2‐amino‐4‐halo‐5,6‐dihydropyrido[2,3‐d]pyrimidin‐7(8H)‐ones
Authors: Victory Pedro , Crespo Ana , Garriga Miquel , Nomen Rosa
Published: April 2009

As the third step of a new general synthesis of pyrido[2,3‐d]pyrimidines, the substitution of the halogens by several nucleophiles has been carried out. Yields are between good and high in every case, even when 4‐halogenated compounds have a neighbouring methyl group in C5.
Hydroxyiminoisoquinolin‐3(2H)‐ones. 9. Synthesis of some oxazolo[5,4‐c]‐, thiazolo[5,4‐c]‐ and 2,3‐dihydro‐1H‐[1,4]oxazino[2,3‐c]isoquinolines
Authors: Tikk István , Deák Gyula , Sohár Pál , Tamás József
Published: April 2009

4‐Acetylamino‐1‐phenyl‐1,4‐dihydro‐3(2H)‐isoquinolinones and 4‐amino‐1‐phenylisoquinolin‐3‐ol, prepared from the corresponding 4‐hydroxyimino compounds, were converted into new isoquinolines containing fused oxazole, thiazole and 1,4‐oxazine rings.
The synthesis of 1‐[(2‐thiazolyl)methyl]quinolones. The reactivity of the methylene bridge at position‐1 and its involvement in the formation of a stable carbon‐nitrogen ylid
Authors: Izzo Patrick T. , Lee Ving J.
Published: April 2009

A series of 7‐chloro‐1,4‐dihydro‐6‐fluoro‐1‐[(2‐methylthiazolyl)methyl]‐4‐oxoquinoline carboxylic esters 5 has been prepared. Dehydration of the intermediates 4‐hydroxythiazolines 4 with trifluoroacetic anhydride resulted in the formation of a ylid 11. Evidence for this was obtained by the X‐ray analysis of the analogous product obtained in reactions carried out with 4‐pyridone.
The formation and X‐ray structure of 6a‐trifluoromethyl‐6a, 12‐dihydro[3,1]benzoxazino[2,1‐b][1,3]‐ benzoxazin‐5‐ones, a new heterocyclic ring system
Authors: Aversa Maria C. , Giannetto Placido , Bruno Giuseppe
Published: April 2009

Four representatives of the new ring system [3,1]benzoxazino[2,1‐b][1,3]benzoxazine, as determined by X‐ray crystallography, were prepared by reaction of N‐(2‐hydroxybenzyl)anthranilic acids with trifluoroacetic anhydride.
The mechanism of the chapman rearrangement of N‐arylbenzimidate on the basis of the molecular structure established by X‐ray. Part II
Authors: Kimura Michio , Okabayashi Ichizo , Isogai Koji
Published: April 2009

Dibenz[c,h]acridine (13) was formed directly by the Chapman rearrangement of 2‐methoxycarbonyl‐1‐naphthyl‐N‐1′‐naphthylbenzimidate (11) without isolation of intermediate 12. When the Chapman rearrangement was carried out under mild reaction conditions, the intermediate 12 was isolated in high yield, whose structure was determined by the X‐ray studies. The mechanism of the Chapman rearrangement can be interpreted on the basis of the X‐ray data of 11 and 12.
Preparation and stereochemistry of methyl 3‐(and 4)‐p‐chlorothiophenoxy‐1‐methylpiperidine‐4‐(and 3)‐carboxylates, and cyclization to benzothiopyranopyridinones
Authors: Butt Graeme L. , Deady Leslie W. , Mackay Maureen F.
Published: April 2009

The title piperidines were prepared by (a) methanolysis of the corresponding nitriles and (b) addition of p‐chlorothiophenol to the appropriate tetrahydropyridines. Three esters were obtained with stereochemistry assigned by nmr analysis: 2 [3(a) SAr, 4(e) CO2Me], 5 [4(e) SAr, 3(e) CO2Me], 6 [4(a) SAr, 3(e) CO2Me]. Compounds 2 and 6 cyclized in 70% sulfuric acid. The product structures were established by X‐ray crystallography and, surprisingly, both had trans‐fused rings. Compound 5, however, did not cyclize but gave 4‐(methylthio)chlorobenzene as the sole isolated product.
Acid‐catalyzed reactions of 3‐(α‐hydroxybenzyl)pyrazolo[1,5‐a]pyridines
Authors: Miki Yasuyoshi , Tomii Osamu , Nakao Hayami , Kubo Mayumi , Hachiken Hiroko , Takemura Shoji , Ikeda Masazumi
Published: April 2009

Treatment of 3‐(or‐hydroxybenzyl)pyrazolo[1,5‐a]pyridines with trifluoroacetic acid in dichloromethane resulted in the formation of pyrazolo[1,5‐a]pyridines, bis[α‐(pyrazolo[1,5‐a]pyrid‐3‐yl)benzyl] ethers, and phenylbis(pyrazolo[1,5‐a]pyrid‐3‐yl)methanes, depending upon the presence or absence of the substituents at the 2‐ and/or 4‐positions and the reaction conditions employed.
Facile rearrangement of 2‐amino‐3‐carbethoxy‐4‐ethylfuro[3,2‐b]pyridinium cation to 2‐oxo‐3‐cyano‐4‐ethyl‐4H‐furo[3,2‐b]pyridine
Authors: Desideri N. , Manna F. , Stein M. L.
Published: April 2009

The rearrangement of 2‐amino‐3‐carbethoxy‐4‐ethylfuro[3,2‐b]pyridinium iodide in basic solution was studied. The reaction product is 2‐oxo‐3‐cyano‐4‐ethyl‐4H‐furo[3,2‐b]pyridine which was obtained also by alkylation with ethyl iodide and sodium hydride in dimethylformamide of 2‐oxo‐3‐cyano‐3H‐furo[3,2‐b]‐pyridine or of p‐nitrophenyl‐3‐acetoxypyridine‐2‐cyanacetate.
Synthesis of new isoxazole aminoalcohols
Authors: Chiarino D. , Fantucci M. , Sala A. , Veneziani C.
Published: April 2009

The preparation of new 1‐isoxazolyl‐2‐amino‐1‐ethanol derivatives is described starting from the corresponding 1‐isoxazolylethanones. It is also reported the synthesis of 1‐(5‐isoxazolyloxy)‐3‐amino‐2‐propanol compounds starting from the corresponding 5‐haloisoxazoles and the obtainment of 1‐(3‐isoxazolyloxy)‐3‐amino‐2‐propanol compounds starting from the methyl 3‐hydroxy‐5‐isoxazolecarboxylate.
Rotenone NMR assignments
Authors: Nunlist Rudi , Ralph John
Published: April 2009

Complete and unambiguous 13C nmr assignments for rotenone have been determined and are presented along with proton nmr data.
Stereochemistry and bonding in N‐substituted‐2‐phenyl‐3‐cyanoaziridines
Authors: Keifer Paul A. , Nagel Donald L. , Cromwell Norman H.
Published: April 2009

A series of ten N‐alkyl(aralkyl)‐2‐phenyl‐3‐cyanoaziridines has been synthesized to continue investigations of the molecular stereochemistry and bonding of functionalized aziridines. Substantial spectroscopic evidence is presented which indicates the presence of stereoselective hyperconjugation between the phenyl and nitrile groups and the aziridine ring. The 1H and 13C nmr chemical shifts are rationalized in terms of the interactions of the substituents on the aziridine ring, and how these interactions vary with the steric bulk of the nitrogen substituents. Various stereoselective coupling constants (1H‐1H and 13C‐1H) are also reported.
The photoreduction of 8‐substituted 5‐deazaflavins and the 5‐deazaflavin catalyzed photoreduction of methyl viologen
Authors: Link Paul A. J. , Van Der Plas Henk C. , Müller Franz
Published: April 2009

Prolonged illumination of 8‐X‐5‐deazaflavins (X = C1, N(CH3)2, NH2, p‐NH2‐C6H4) in the presence of an electron donor leads to the formation of a 5,5′‐dimer and/or a 6,7‐dihydro compound. The course and rate of these photoreductions were established and discussed in terms of electronic and steric effects, exerted by the substituent at position 8 and the electron donor. Pseudo first‐order kinetics were found to apply to the photoreduction of 8‐X‐5‐deazaflavins (X = Cl, NH2, p‐NH2‐C6H4) while the rate of the photoreduction of 8‐X‐5‐deazaflavin (X = N(CH3)2) appeared to contain an autocatalytic element. The catalytic effect of 8‐X‐5‐deazaflavins in the photoreduction of methyl viologen by EDTA was investigated. The substituent effect on the rate of the 8‐X‐5‐deazaflavin mediated photoreduction of methyl viologen by EDTA was found to be comparable with that on the photoreduction rate of 8‐X‐5‐deazaflavin in the presence of EDTA with the exception of 8‐X‐5‐deazaflavin (X = N(CH3)2), which showed a remarkable relative enhancement of the reactivity towards methyl viologen photoreduction.
Preparation and proton spectra of 1‐aryl‐1,2‐dihydro‐2‐quinolones
Authors: Wawzonek Stanley , Van Truong Thien
Published: April 2009

1‐Phenyl‐, 1‐m‐tolyl‐ and 1‐p‐tolyl‐1,2‐dihydro‐2‐quinolone have been prepared by treating the potassium derivative of 1,2‐dihydro‐2‐quinolone with the corresponding aryl bromide in the presence of finely divided copper. The use of o‐bromotoluene in this reaction gave trace amounts of a crystalline material which upon the basis of mass spectrum analysis was assigned 2‐o‐tolyloxyquinoline as a structure. The 1‐aryl groups caused an unusual chemical shift of the 8‐proton to the Δ 6.64–6.70 region. This behavior paralleled that observed for the 7‐proton of 6‐phenyl‐6H‐indeno[1,2‐c]isoquinoline‐5,11‐dione in earlier studies.
Apurinic DNA reactivity: Modelisation of apurinic DNA breakage with phenylhydrazine and formation of a pyrazole adduct
Authors: Vasseur Jean‐Jacques , Rayner Bernard , Imbach Jean‐Louis
Published: April 2009

We have elucidated the exact mechanism of apurinic oligodeoxynucleotide d(Tp[AP]pT) cleavage by phenylhydrazine and shown that the final isolated product is in fact a 3‐substituted derivative of 1‐phenyl‐pyrazole.
Synthesis of fused ring heterocycles from aromatic amines with hydroximoyl chlorides
Authors: Abdelhamid Abdou O. , Párkányi Cyril , Rashid S. M. Khaledur , Lloyd Winston D.
Published: April 2009

Substituted 2‐arylbenzimidazoles, 2‐arylbenzoxazoles and 2‐arylbenzothiazoles were obtained in good yield by the reaction of hydroximoyl chlorides with ortho‐substituted aromatic amines. The benzo moiety of the benzimidazoles was shown by nmr to be symmetrical, indicating that the N‐H group proton of the imidazole ring is exchanging with the water protons in the DMSO‐d6 solvent.
The role of exciplexes in the photoreduction of quinolinemethanols
Authors: Epling Gary A. , Lin Kuei‐Ying , Kumar Anil
Published: April 2009

The photoreduction of a family of quinolinemethanols has been examined both in the presence and absence of exciplex‐forming additives. Photoreduction of the alcohol group and cleavage of the side chain occurs on direct photolysis. However, irradiation with triethylamine led to predominant cleavage of the side chain while irradiation with 1,3‐dicyanobenzene predominantly led to photoreduction of the alcohol functionality. A variety of other experiments supported the involvement of exciplexes in these transformations.
Regioselectivity in methylation and phenylation of the zwitterionic pyrido[2,1‐f]‐as‐triazinium‐1‐ and 3‐olates and thiolates
Authors: Bátori Sándor , Messmer András
Published: April 2009

Substituted derivatives of the title ring system have been synthesized and the regioselectivity in methylation and phenylation of the zwitterionic pyrido[2,1‐f]‐as‐triazinium 1‐ and 3‐olates 4a‐g and 10 and thiolates 7a,b and 12 has been studied by nmr techniques. Depending on the soft or hard nature of the used reagent (methyl iodide, trimethyloxonium hexafluorophosphate or diphenyliodonium tetrafluoroborate), the reaction yielded NMe 5 and/or OMe 6,11a and NPh 14 or OPh 11b products in the case of olates; while thiolates gave NMe 8 and/or SMe 9,13a and SPh 13b, 15 compounds. Mechanistic suggestions are given to rationalize the observed phenomena.
The synthesis of 1‐alkyl‐4a‐(4‐chlorophenyl)‐ 4,4a‐dihydropyrimido[6,1‐a]isoindol‐9(3H)‐one
Authors: Eberle Marcel K. , Brzechffa Leszek
Published: April 2009

The primary amino group of 3‐(2‐aminoethyl)‐3‐(4‐chlorophenyl)‐2,3‐dihydro‐1H‐isoindol‐1‐one (1) was acylated with acetyl chloride, benzoyl chloride and phenyl acetyl chloride to form the amides 2a‐c, respectively. These were cyclized in phosphorus oxychloride to give the 1‐substituted‐4a‐(4‐chlorophenyl)‐4,4a‐dihydropyrimido [6,1‐a]isoindol‐9(3H)‐ones 3a‐c. Heating of 1 in formic acid lead to the formation of 4a‐(4‐chlorophenyl)‐4,4a‐dihydropyrimido[6,1‐a]isoindol‐9(3H) ‐one (3d). Heating of 1 in the presence of phosgene lead to the formation of 4a‐(4‐chlorophenyl)‐2,3,4,4a‐tetrahydropyrimido[6,1‐a]isoindole‐1, 9‐dione (4).
Reactions of hydroxybenzophenone with hydrazines
Authors: Krishnan Raghavan , Lang S. A. , Lin Yang‐I , Wilkinson Raymond G.
Published: April 2009

The reaction of 2,2′,4,4′‐tetrahydroxybenzophenone with hydrazines under different conditions gave the corresponding indazol‐1,3‐benzenediol derivatives. It is an interesting and unique approach to the synthesis of indazoles. However, the reactions of 2‐hydroxybenzophenone and 2,2′‐dihydroxybenzophenone under the same conditions yielded only the hydrazones.
Régio et périsélectivité de réactions de diels‐alder et des cycloadditions dipolaires‐1,3 avec une triazépine‐1,2,4: Approche théorique
Authors: Hasnaoui A. , El Messaoudi M. , El Mouthadi M. , Goupil J.‐M. , Lavergne J.‐P.
Published: April 2009

La cycloaddition de dipoles‐1,3 (mésitonitrile, C,N‐diméthyle nitrone) et de divers diénophiles (DMAD, anhydride maléïque) à la triazépine‐1,2,4 sont péri et régiospécifiques. Abstraction faite du nitrone, l'orientation préférentielle de l'addition est en accord avec les calculs FMO/MNDO.
Synthesis of an optically active 4‐acetoxyazetidinone intermediate for penems and carbapenems
Authors: Häbich Dieter , Hartwig Wolfgang , Born Liborius
Published: April 2009

The synthesis of the novel (3R,4R)‐4‐acetoxy‐3‐[(1S)‐1‐t‐ butyldimethylsilyloxymethyl‐1‐((1S)‐1‐ phenylethylaminocarbonyl)]azetidin‐2‐one (1a), a valuable key intermediate for penems and carbapenems bearing a 6‐hydroxyacetamide side chain, and its diastereomer 1b, from dimethyl cis‐2,3‐oxirane dicarboxylate, is described. The allocation of absolute configurations to the diastereomers 1a and 1b ensued via single‐crystal X‐ray analysis of the isomer 1b.
Synthesis of imidazo[5,4‐d] [1,3]thiazines: X‐ray structure of N‐methyl‐N′‐[5‐(methylamino)‐3‐nonylimidazo[5,4‐d] [1,3]thiazin‐7(3H)‐ylidene]thiourea
Authors: Grözinger Karl G. , Onan Kay D.
Published: April 2009

N‐Alkyl‐N′‐[5‐(alkylamino)‐3‐alkylimidazo[5,4‐d] [1,3]thiazin‐7(3H)‐ylidene]thioureas were obtained by the reaction of 1‐substituted 5‐amino‐4‐cyanoimidazoles with alkyl isothiocyanates. The structure of this heterocyclic system was confirmed by single crystal X‐ray diffraction analysis.
Selenium dioxide oxidation of alkylcoumarins and related methyl‐substituted heteroaromatics
Authors: Ito Kiichi , Nakajima Kaoru
Published: April 2009

By the use of selenium dioxide as the specific oxidizing agent in the coumarin series, the 4‐ethyl, 4‐propyl and 4‐benzyl substituents of coumarin were converted into α‐alcohols 2 and/or ketones 3, while 3‐methyl‐ and 3‐benzylcoumarins were converted into 3‐acyl derivatives 7. The methyl substituent of the analogous thiocoumarin 5, chromones 10 or thiochromone 11 was also oxidized into the formyl functionality. Facile oxidative desulfurization into the ketone functionality, prior to methyl oxidation, was observed for the thione derivatives of 1a, 5, 6 and 10.