bluuebunny/crossref_metadata_2025 huggingface dataset:
The synthesis of 5‐azaindoles by substitution‐rearrangement of 7‐azaindoles upon treatment with certain primary amines
Authors: Girgis Nabih S. , Larson Steven B. , Robins Roland K. , Cottam Howard B.
Published: March 2009

Certain 4‐substituted 1H‐pyrrolo[2,3‐b]pyridines (7‐azaindoles) undergo a nucleophilic substitution‐rearrangement upon treatment with various primary amines at elevated temperatures to yield N‐1‐substituted 4‐amino‐1H‐pyrrolo[3,2‐c]pyridines (5‐azaindoles). Treatment of the same 7‐azaindoles with secondary amines under the same reaction conditions led to simple nucleophilic substitution products.
Novel tricyclic heterocycles (benzopyrrocolines) arising via carbanion attack on a nitrile function
Authors: Gibson Harry W.
Published: March 2009

A new reaction of 2‐n‐alkanoyl‐1,2‐dihydroisoquinaldonitriles 1 (isoquinoline Reissert compounds) has been discovered. As previously reported reaction of the conjugate bases of Reissert compounds with alkyl halides yields the corresponding 1‐alkyl derivatives 2. However, compounds 2, R = n‐alkyl, with only a catalytic amount of bases form the enolate ion, which attacks the neighboring nitrile functionality to produce directly in the same reaction vessel excellent yields of benzopyrrocoline derivatives 5‐10. The nmr spectrum reveals a solvent dependent tautomeric equilibrium between ketoeneamine (a) and ketoimine (b) forms. Unlike compounds 2 the double bonds of the pyridine ring of compounds 7 and 8 were readily reduced with hydrogen. Thus, n‐alkanoyl Reissert compounds afford a convenient route to the corresponding benzopyrroco‐lines.
Synthesis of 3‐carboethoxy‐4,11‐dihydro‐11‐alkyl/phenyl‐4‐oxopyrimido[1,2‐b][1,2,4]benzothiadiazine 6,6‐dioxides. A novel heterocyclic ring system
Authors: Murthy M. S. R. , Nageswar Y. V. D. , Reddy A. V. Narender , Ramalingam T. , Sattur P. B.
Published: March 2009

The synthesis of some novel 3‐carboethoxy‐4,11‐dihydro‐11‐alkyl/phenyl‐4‐oxopyrimido[1,2‐b][1,2,4]benzo‐thiadiazine 6,6‐dioxides (IVa‐c) from 3‐amino‐4‐alkyl/phenyl‐4H‐1,2,4‐benzothiadiazine 1,1‐dioxides (1a‐c) and diethyl ethoxymethylenemalonate (II) is described. The compounds have been screened for their antibacterial activity.
Synthesis and in solution behaviour of new 2‐substituted‐4‐thiazolidinecarboxylic acid derivatives
Authors: Chiarino D. , Ferrario F. , Pellacini F. , Sala A.
Published: March 2009

A number of 2‐substituted‐4‐thiazolidinecarboxylic acid derivatives were synthesized by cyclocondensation of L‐cysteine or its esters with various aldehydes, resulting from acids provided with antiinflammatory properties. In the cyclocondensation a new chiral center at C‐2 position of thiazolidine ring is formed giving rise to a mixture of diastereoisomers which can be partially separated. These diastereoisomers show in solution a fast epimerisation at the same chiral center as evidenced by 1H‐nmr studies.
Reactions of 2‐aminothiobenzamide with isocyanates: A new synthesis of 2, 3‐dihydroimidazo[1, 2‐c]quinazolin‐5(6H)‐one and 3, 4‐Dihydro‐2H‐pyrimido[1, 2‐c]quinazolin‐6(7H)‐one
Authors: Shiau Chia‐Yang , Chern Ji‐Wang , Tien Jung‐Hsiung , Liu Kang‐Chien
Published: March 2009

2‐(2‐Chloroethylureido)‐ and 2‐(3‐chloropropylureido)thiobenzamides 5a, b were prepared in good yields by treating 2‐aminothiobenzamide with 2‐chloroethyl and 3‐chloropropyl isocyanates respectively. Subsequent treatment of compound 5a and 5b either with alkali or mineral acid led to the formation of 2, 3‐dihydro‐imidazo[1, 2‐c]quinazolin‐5(6H)‐one 7a and 3, 4‐Dihydro‐2H‐pyrimido[1, 2‐c]quinazolin‐6(7H)‐one 7b.
Thermally induced fragmentation and cyclisation of C‐azidohydrazones
Authors: Bruché Luca , Garanti Luisa , Zecchi Gaetano
Published: March 2009

C‐Azidohydrazones 2 were synthesized from the corresponding C‐chlorohydrazones 1 and submitted to thermal decomposition in boiling benzene. Various kinds of products were obtained due to competitive modes of evolution of first‐formed nitrenes 13, namely hydrogen abstraction to form aminohydrazones 3 and benzotriazepine 8, and radical fragmentation to give ultimatively diaryls 4 and arylglyoxylate arylhydrazones 5. Ring‐closed products, namely 1, 2, 4‐triazoles 6 and imidazolones 7 were also formed.
Carbon‐13 nuclear magnetic resonance spectra of fentanyl analogs
Authors: Brine G. A. , Boldt K. G. , Huang P.‐T. , Sawyer D. K. , Carroll F. I.
Published: March 2009

Natural abundance carbon‐13 chemical shifts are reported for the hydrochloride salts of fentanyl (1a) and fifteen analogs. The signals are assigned on the basis of chemical shift theory, SFORD multiplicities, signal intensities, comparisons with model compounds, and thiophene carbon‐proton coupling constants. In addition to its forensic value, the data suggest that the solution conformations of the analogs are similar to that of fentanyl hydrochloride.
Synthesis of new tricyclic ring systems containing the pyrimido[5, 4‐b][1, 4]oxazine skeleton
Authors: Mátyus Péter , Szalay Luca , Kasztreiner Endre , Jerkovich Gyula , Rabloczky György
Published: March 2009

Synthesis of derivatives 4 and 6 of two novel tricyclic ring systems, 1, 2, 4‐triazolo[3, 4‐c]pyrimido[5, 4‐b]‐[1, 4]oxazine and imidazo[1, 2‐c]pyrimido[5, 4‐b][1, 4]oxazine, respectively is described. Although the parent pyrimido[5, 4‐b]oxazines possess positive inotropic activity, the tricyclic compounds are practically inactive.
Alkaline hydrolysis of 3‐methyl‐2H‐1, 3‐benzothiazinium iodides
Authors: Szabó János , Bernáth Gábor , Sohár Pál
Published: March 2009

Alkaline hydrolysis of the 3‐methyl‐2H‐1, 3‐benzothiazinium iodide 5a and of its 4‐aryl derivatives 5b, c in the presence of hexacyanoferrate(III)ion resulted in the formation of 2, 2′‐diaryloxodiphenyl disulfides 6a‐c. In contrast, the 4‐benzyl derivative 5d underwent hydrogen iodide elimination to give the enamine 7. Mechanisms are proposed for the reactions.
Behaviour of aminoacids and aliphatic aldehydes in dipolar aprotic solvents: Formation of oxazolidinones—behaviour of aminoacids and aliphatic aldehydes in dipolar aprotic solvents
Authors: Orsini F. , Pelizzoni F. , Forte M. , Sisti M. , Bombieri G. , Benetollo F.
Published: March 2009

Reactions of aliphatic branched aldehydes with proline in dimethyl sulfoxide or acetonitrile solution afford oxazolidin‐5‐ones with high diastereoselection. Linear aldehydes afford aldolic/crotonic condensation products; with short reaction times, the presence of Oxazolidinones can be detected in the pmr spectra. Acyclic aminoacids and branched aldehydes yield a reaction mixture the pmr and ir spectra of which give evidence for iminic‐oxazolidinone equilibria. The structure of (2R,5S)‐2‐trichloromethyl‐1‐aza‐3‐oxabiciclo‐[3.3.0]octan‐4‐one has been confirmed by X‐ray diffraction analysis.
S,S'‐ and S,N‐disubstituted derivatives of 1,3,4‐thiadiazoledithiones
Authors: Katritzky Alan R. , Wang Zouquan , Offerman Rick J.
Published: March 2009

Facile synthesis of 2‐n‐dodecylthio‐4‐phenylthiomethyl‐1,3,4‐thiadiazole‐5‐thione 6, starting from 2,5‐dimercapthothiadiazole via 2‐n‐dodecylthio‐1,3,4‐thiadiazole‐5‐thione 2, 2‐n‐dodecylthio‐4‐hydroxymethyl‐1,3,4‐thiadiazole‐5‐thione 4 and 2‐n‐dodecylthio‐4‐chloromethyl‐1,3,4‐thiadiazole‐5‐thione 5 is described.
The stereochemical investigation of 3‐Aryl‐4‐methyl‐1,2,3‐oxathiazolidine 2‐oxides using NMR
Authors: Nishiyama Tomihiro , Takahama Yasumitsu , Yamada Fukiko
Published: March 2009

The title compounds were prepared by the reaction of the corresponding N‐2‐hydroxyisopropylanilines with thionyl chloride in the presence of triethylamine, and their pmr and cmr spectra were examined. On the basis of the chemical shifts due to the γ‐ and δ‐effects, the stereochemical structures are discussed.
Mechanism of the cycloaddition‐elimination reactions of 4‐methyl‐5‐phenylimino‐δ2‐1,2,3,4‐thiatriazoline with alkyl and aryl isothiocyanates
Authors: L'Abbé Gerrit , Buelens Karin
Published: March 2009

The formation of thiadiazolidines 3a‐c and dithiazolidines 4a‐c and 5a‐b from the title reactions has been studied in detail under a variety of conditions. On the basis of kinetic measurements, isomerization studies and cross experiments a mechanism is proposed involving path (b) (Scheme 1) as the first step, followed by a series of isomerizations as shown in Scheme 3.
A facile synthesis of 3‐aryl‐4‐pyrazoleacetic acids and of their 4,5‐dihydro derivatives
Authors: Curzu Maria M. , Pinna Gérard A. , Barlocco Daniela , Cignarella Giorgio
Published: March 2009

N‐1‐Unsubstituted‐3‐aryl‐4‐pyrazoleacetic acids and their 4,5‐dihydro derivatives can conveniently be prepared by cyclization of 3‐benzoyl‐3‐butenoic acids with hydrazine hydrate in acetic acid and subsequent treatment with bromine in acetic acid or, respectively, with diluted mineral acids.
Mass spectra of 3(2H)‐cinnolinone and 2‐substituted derivatives
Authors: Zey Robert L. , Gross Michael L. , Groenewold Gary S.
Published: March 2009

The mass spectrum of 3(2H)‐cinnolinone indicates that it undergoes fragmentation in a fashion similar to other heterocyclic systems containing two vicinal nitrogens. The initial fragmentation, loss of CO, gives a 1H‐indazole radical cation, as was shown by deuterium labelling and metastable ion spectra. Four 2‐substituted‐3(2H)‐cinnolinones were also studied and it was found that their fragmentation patterns are highly influenced by the substituent groups.
5‐Oxo‐1,4‐dihydroindenopyridines: Calcium modulators with partial calcium agonistic activity
Authors: Rose Ulrich
Published: March 2009

The title compounds 4a‐g were prepared by Knoevenagel reactions of 1,3‐indandione (1) with the aromatic aldehydes 2a‐g followed by cyclizing Michael addition of the products thus obtained with methyl β‐aminocrotonate (3). The structures of products 4 were characterized by spectal data. Positive inotropic activities were observed on electrically stimulated, left atria of giunea pigs and these effects could be attributed to calcium agonism. On the other hand, barium chloride‐induced contractions of guinea pig ileum were inhibited in a dose‐dependent manner.
Acetylenic chemistry: Part15[1]. Reactions of 1,2,3,4‐Tetrahydro‐2,4‐dioxopyrido[2,3‐d]pyrimidine with 3‐bromoprop‐1‐yne
Authors: Reisch J. , Usifoh [2] C. O. , Oluwadiya J. O.
Published: March 2009

Reaction of 1,2,3,4‐tetrahydro‐2,4‐dioxopyrido[2,3‐d]pyrimidine with 3‐bromoprop‐1‐yne gave 1‐prop‐2′‐ynylpyrido[2,3‐d]pyrimidine‐2,4‐dione (4a), 3‐prop‐2′‐ynylpyrido[2,3‐d]pyrimidine‐2,4‐dione (4b), and 1,3‐diprop‐2′‐ynylpyrido[2,3‐d]pyrimidine‐2,4‐dione (4c). Subsequent boiling of 1,3‐diprop‐2′‐ynylpyrido‐[2,3‐d]pyrimidine‐2,4‐dione (4c) in formic acid afforded 1‐methylimidazo[1,2‐a]pyridyl‐N‐prop‐2′‐ynylamide (5) and 1‐acetonyl‐3‐prop‐2′‐ynylpyrido[2,3‐d]pyrimidine‐2,4‐dione (6).
Functionalized di‐ and tetrathia‐crowns and their use to quantitatively separate and recover gold(III), palladium(II), silver(I) and mercury(II) Ions
Authors: Bradshaw Jerald S. , Krakowiak Krzysztof E. , Izatt Reed M. , Bruening Ronald L. , Tarbet Bryon J.
Published: March 2009

Two new dithia‐crowns containing a hydroxy group and 1,4,7,10‐tetrathia‐18‐crown‐6 containing an allyl‐oxymethyl substituent were prepared in good yields. Two of these crowns were covalently attached to silica gel. The silica gel‐bound thia‐crowns were used to separate gold(III), palladium(II), silver(I) and mercury(II) ions from an aqueous 0.1 M nitric acid solution which also contained 1.0 M ferric chloride.
Michael additions to acrylonitrile, methyl acrylate and methyl vinyl ketone to Nb‐benzylidenetryptophan methyl ester
Authors: Braña Miguel F. , Garrido Mercedes , López Rodríguez María L. , José Morcillo M.
Published: March 2009

Michael addition to methyl acrylate and methyl vinyl ketone of Nb‐benzylidene‐L‐tryptophan methyl ester 1 gave 2‐(3‐indolylmethyl)glutamic dimethyl ester 2a and α‐(3‐oxobutyl)tryptophan methyl ester 2b respectively. Addition to acrylonitrile of 1 yielded α,Na‐dicyanoethyltryptophan methyl ester 3.
Pyridazines with heteroatom substituents in positions 3 and 5. 6. SN reactions in position 5 of 2‐aryl‐5‐hydroxypyridazin‐3(2H)‐ones
Authors: Schober Bernt D. , Megyeri Gabor , Kappe Thomas
Published: March 2009

The nucleophilic introduction of chloro‐ (2), azido‐ (4), (substituted) amino (3, 6), mercapto (10) and hydrazino‐groups (13) into 2‐aryl‐5‐hydroxypyridazin‐3(2H)‐ones [3] is described. The 5‐aminopyridazin‐3(2H)‐one (6) also reacts with activated malonates 8 [4] to give pyrido[2,3‐d]pyridazines 9. Hydrazino compounds 13 can be treated with aldehydes to yield compounds 14. Iodine can be introduced into position 4 of 5‐amino‐(15) and 5‐hydroxypyridazin‐3(2H)‐ones (17) by electrophilic substitution to afford compounds 18.
A simple synthesis of novel 2‐pyridones from chalcones
Authors: Al‐Arab Mohammad M.
Published: March 2009

Several novel 2‐pyridones were synthesized in good yields from a simple one‐pot reaction by the condensation of different substituted chalcones and malonamide using sodium ethoxide in ethanol at room temperature. The structures of these 2‐pyridones were elucidated from their 1H, 13C and infrared spectral data as well as their elemental analysis. Different 2‐pyridones tautomers were obtained as the solvent of crystallization changes.
Sels de N‐alcoxyquinoléinium et de N‐alcoxyisoquinoléinium porteurs d'une fonction ester dans leur chaine alcoxyle: Synthèse et réactivité vis‐a‐vis des ions cyanure
Authors: Sliwa Henri , Randria‐Raharimanana Clarisse , Ouattara Lassina
Published: March 2009

Reaction of ethyal α‐bromoisobutyrate on quinoline 1‐oxide and isoquinoline 2‐oxide in the presence of silver perchlorate leads to the corresponding N‐alkoxyl salts 1 and 2. On treatment with potassium cyanide, these salts are converted into 2‐cyanoquinoline and 1‐cyanoise‐quinoline according to mode B of the Katritzky' s classification concerning the reaction of nucliophiles on N‐alkoxypyridinium salts. When the reaction of cyanide ions were performed on salt 1 at 0° in aqueous solution the dihydro aromatic 4 was isolated. This result confirms the addition‐elimination mechanism of the reaction studied.
2‐Methylpyridinium salts as 1,4‐dinucleophiles. IV. Westphal condensation with 2‐alkyl‐1‐aminoazinium substrates
Authors: Matia M. Paz , Navío J. Luis Garcia , Vaquero J. José , Alvarez‐Builla J.
Published: March 2009

Condensation of 2‐alkyl‐1‐aminopyridinium, quinolinium or 1‐alkyl‐2‐aminoisoquinolinium salts with 1,2‐acenaphthenequinone or 9,10‐phenanthrenequinone in the presence of base, gave pyrido[1,2‐b]pyridazinium salts in good yields.
The preparation of 5‐substituted thieno[2,3‐b]furan‐2‐sulfonamides
Authors: Hartman George D. , Halczenko Wasyl , Prugh John D. , Williams Theresa M.
Published: March 2009

An efficient synthetic route is reported for the preparation of thieno[2,3‐e]furan‐2‐sulfonamides bearing oxygenated functionality at C‐5. The method employs conversion of furan‐3‐carboxaldehyde to an intermediate that, in the key step, undergoes facile cyclodehydration to the fused [5,5] heterocycle under mild Knoevenagel conditions.
Synthesis of new derivatives of β‐carboline‐hydantoin
Authors: Braña Miguel F. , Garrido Mercedes , Rodriguez María L. López , Miguel Pilar , Morcillo M. José , Riaño A.
Published: March 2009

Reaction of tetrahydro‐β‐carboline‐3‐carboxylic acids 4a‐c with alkyl and phenyl isocyanates in acetone provide the corresponding 2,5‐disubstituted 1,3‐dioxo‐6H‐1,2,3,5,11,11a‐hexahydroimidazo[1,5‐b]‐β‐carbolines 2a‐r.
The crystal and molecular structure of 5‐N‐methyl‐β‐d‐arabinofurano[1′,2′:4,5]oxazolo‐S‐triazine‐4,6‐dione: Molecular modeling studies on the pattern of alkylation of β‐D‐arabinofurano[1′,2′:4,5]oxazolo‐s‐triazin‐4‐one‐6‐thione
Authors: Purkayastha Subhasish , Cheer Clair J. , Panzica Raymond P.
Published: March 2009

The involvement of the 5′‐hydroxyl group on β‐D‐arabinofurano[1′,2′:4,5]oxazolo‐s‐triazin‐4‐one‐6‐thione (1b), to form an intramolecular covalent adduct at C6, is postulated to explain the formation of almost equal amounts of 5‐N‐alkyl‐β‐D‐arabinofurano[1′,2′:4,5]oxazolo‐s‐triazin‐4‐one‐6‐thione and 5‐N‐alkyl‐β‐D‐arabinofurano[1′,2′:4,5]oxazolo‐s‐triazine‐4,6‐dione during alkylation of 1b. An X‐ray crystallographic study was conducted on 5‐N‐methyl‐β‐D‐arabinofurano[1′,2′:4,5]oxazolo‐s‐triazine‐4,6‐dione (2a) and its solid state structure was established. This was compared to the energy minimized structure of the same compound that was generated by the molecular modeling program, MACROMODEL. Force field calculations (Allinger's MM2) on this structure and other intermediates lend support to the concept of formation of the intramolecular covalent adduct.
A facile synthesis of certain 4‐ and 4,5‐disubstituted 1‐β‐d‐ribofuranosylpyrazoles
Authors: Bhattacharya Birendra K. , Robins Roland K. , Revankar Ganapathi R.
Published: March 2009

A number of pyrazole ribonucleosides, structurally related to AICA riboside and ribavirin have been prepared and evaluated for their biological activity in vitro. Deisopropylidenation of 5‐amino‐1‐(2,3‐O‐isopropylidene‐β‐D‐ribofuranosyl)pyrazole‐4‐carbonitrile (6) with aqueous trifluoroacetic acid gave 5‐amino‐1‐(β‐D‐ribofuranosyl)pyrazole‐4‐carbonitrile (7). Conventional transformation of the carbonitrile function of 7 gave the AICA riboside congener (2) and related 5‐amino‐1‐(β‐D‐ribofuranosyl)‐pyrazoles (8–10). Acetylation of 7 at low temperature gave the versatile intermediate 5‐amino‐1‐(2,3,5‐tri‐O‐acetyl‐β‐D‐ribofuranosyl)pyrazole‐4‐carbonitrile (15). Non‐aqueous diazotization of 15 with isoamylnitrite in dibromomethane or diiodomethane gave the corresponding C5‐bromo 13 and C5‐iodo 16 derivatives. Compounds 13 and 16 were subsequently transformed into 5‐bromo‐1‐(β‐D‐ribofuranosyl)pyrazole‐4‐carboxamide (11) and the 5‐iodo analog 25. However, a similar nonaqueous diazotization of 15 in dichloromethane afforded the deaminated product 1‐(2,3,5‐tri‐O‐acetyl‐β‐D‐ribofuranosyl)pyrazole‐4‐carbonitrile (22). Treatment of 22 with ammonium hydroxide/hydrogen peroxide gave the ribavirin congener 1‐(β‐D‐ribofuranosyl)pyrazole‐4‐carboxamide (18). Similar treatment of 22 with hydrogen sulfide in pyridine or hydroxylamine in ethanol gave the 4‐thiocarboxamide 19 and 4‐carboxamidoxime 20 derivatives, respectively. Catalytic hydrogenation of 20 afforded 1[β‐D‐ribofuranosyl)pyrazole‐4‐carboxamidine (21). These pyrazole nucleosides are devoid of any significant antiviral or antitumor activity in vitro.
A new synthesis of dl‐5‐vinyloxazolidine‐2‐thione, a natural antithyroid factor
Authors: Gardrat C. , Latxague L. , Picard J. P.
Published: March 2009

A new procedure for the preparation of DL‐5‐vinyloxazolidine‐2‐thione (goitrin) 3 via a facile and practical synthesis of the key intermediate DL‐1‐amino‐3‐buten‐2‐ol 2 is described.
Temperature‐dependent reaction of 1,4,6‐triaminopyrimidine‐2(1H)‐thiones with vilsmeier reagent. formation of [1,2,4]triazolo[1,5‐c]pyrimidin‐5(6H)‐ones
Authors: Tsuji Tadakazu , Takenaka Keiko
Published: March 2009

5,7‐Diamino[1,3,4]thiadiazolo[3,2‐a]pyrirnidinium chloride 2, 7‐amino[1,2,4]triazolo[1,5‐c]pyrimidine‐5(6H)‐thiones 3 and the 5(6H)‐one derivative 4a were synthesized by the reaction of 1,4,6‐triaminopyrimidine‐2(1H)‐thione 1 with phosphoryl chloride and N,N‐dimethylacylamides. Further, compounds 4 were prepared from 2, 3 or 1,4,6‐triaminopyrimidin‐2(1H)‐one 6 by the treatment with the above reagents. Compounds 3 and 4 were converted to 7‐amino[1,2,4]triazolo[1,5‐c]pyrimidin‐5(6H)‐ones 5.
Heterocyclic photorearrangements. Photoinduced rearrangement of 3‐styryl‐1,2,4‐oxadiazoles
Authors: Buscemi Silvestre , Cusmano Giuseppe , Gruttadauria Michelangelo
Published: March 2009

The photochemical behaviour of 3‐styryl‐5‐phenyl‐(5‐methyl)‐1,2,4‐oxadiazoles in methanol at 254 nm has been investigated. A photoinduced rearrangement to the quinoline system has been pointed out and explained as proceeding through an initial photolysis of the ring ON bond, followed by a six membered ring closure reaction involving the styryl moiety.
An approach towards the synthesis of 4‐phenyl‐5‐arylimino‐δ2‐1,2,3,4‐thiatriazolines
Authors: L'Abbé Gerrit , Franek Walter , Toppet Suzanne , Delbeke Pieter
Published: March 2009

4‐Phenyl‐5‐arylimino‐δ2‐1,2,3,4‐thiatriazolines are presumably formed by reacting 5‐arylaminothiatriazoles with benzyne at 50°, but decompose in situ to benzothiazole derivatives by way of the two pathways (a) and (b) shown in Scheme 4.
One‐step methods to prepare cryptands and crowns containing reactive functional groups
Authors: Krakowiak Krzysztof E. , Bradshaw Jerald S. , Izatt Reed M.
Published: March 2009

A one‐step synthesis of cryptand [2.2.2] containing three methylenyl substituents in a 25% yield from the reaction of triethanolamine and 3‐chloro‐2‐chloromethyl‐1‐propene is described. A similar cryptand was prepared in 56% yield by a two‐step process. One‐step syntheses of N,N‐hydroxyethyl‐diaza‐18‐crown‐6 and crown‐6 compounds containing two alkene functional groups are also described.
Synthesis of 3,4,6‐trisubstituted cinnolines by intramolecular wittig reaction of ortho‐carbonyl substituted arylazomethylenetriphenylphosphoranes
Authors: Licandro Emanuela , Maiorana Stefano , Papagni Antonio , Tarallo Daniele , Slawin Alexandra M. Z. , Williams David J.
Published: March 2009

This paper reports the first example of Wittig reaction on arylazomethylenetriphenylphosphoranes, producing the new cinnolines 6 and 7. A new unexpected rearrangement reaction producing quinoline 8 is also reported. The structure of compound 8 was determined by X‐ray analysis.
A New method for the synthesis of 4‐oxo‐4,5‐dihydrofuro[3,2‐c]quinoline
Authors: Gronowitz Salo , Timari Géza
Published: March 2009

A new method for the synthesis of 4‐oxo‐4,5‐dihydrofuro[3,2‐c]quinoline is the Pd(0)‐catalyzed coupling of o‐bromonitrobenzene with 3‐formyl‐2‐tributylstannylfuran, followed by reductive ring closure to furo[3,2‐c]quinoline N‐oxide and rearrangement.
Annelated piperazinyl‐7,8‐dihydro‐6H‐thiopyrano[3,2‐d]pyrimidines
Authors: Wu M. T. , MacCoss M. , Ikeler T. J. , Hirshfield J. , Arison B. H. , Tolman R. L.
Published: March 2009

Tricyclic analogs of piperazinylthiopyrano[3,2‐d]pyrimidine hypoglycemic agents were prepared. The angular tricyclic systems, 8,9‐dihydro‐7H‐thiopyrano[2,3‐e][1,2,4]triazolo[4,3‐a]pyrimidine and 8,9‐dihydro‐7H‐tetrazolo[1,5‐a]thiopyrano[2,3‐e]pyrimidine derivatives were synthesized from 2,4‐dichloro‐7,8‐dihydro‐6H‐thiopyrano[3,2‐d]pyrimidine in three step sequences. Derivatives of the linear tricyclic system, 5,6‐dihydro‐7H‐thiopyrano[3,2‐d][1,2,4]triazolo[2,3‐a]pyrimidine, were prepared by condensation of 3‐amino‐1,2,4‐triazole with ethyl 3‐oxo‐tetrahydropyran‐2‐carboxylate. The tricyclic heteroaryl‐piperazines lacked significant hypoglycemic activity.
Polycyclic N‐hetero compounds. XXXIII. Syntheses of 4‐substituted 6,7‐dihydro‐5H‐benzo[6,7]‐cyclohepta[1,2‐d]pyrimidines and their inhibitory activities on platelet aggregation and on reserpine‐induced hypothermia
Authors: Sasaki Kenji , Hirota Takashi , Arimoto Yuichi , Satoh Yoshiko , Ohtomo Hiromi , Nakayama Taiji
Published: March 2009

Various 4‐substituted 6,7‐dihydro‐5H‐benzo[6,7]cyclohepta[1,2‐d]pyrimidines were synthesized by the reaction of 4‐chloro‐6,7‐dihydro‐5H‐benzo[6,7]cyclohepta[1,2‐d]pyrimidine with amines. Their inhibitory activities against collagen‐induced platelet aggregation and also against reserpine‐induced hypothermia in mice were investigated.
Heterocyclic X‐azolopyridine intermediates
Authors: Viscardi Guido , Savarino Piero , Barni Ermanno , Carpignano Rosarina
Published: March 2009

A series of heterocyclic coupling agents having tuned hydrophobic chains, has been prepared by reaction of diamino or hydroxy‐aminopyridines and p‐aminosalicylic acid. The acetylation of amino group and hydroxyl in oxazole derivatives showed a selectivity depending on wheter acetic anhydride or acetyl chloride was used. Correlations between structure and spectroscopic data, including related compounds previously described, are reported.
Synthesis of tetra‐substituted furan derivatives from 1‐arylpropane‐2,3‐diones
Authors: Jones A. M. , Simpson A. J. , Stanforth S. P.
Published: March 2009

1‐Arylpropane‐2,3‐diones 4 gave 2‐dimethylamino‐3‐formyl‐4‐chloro‐5‐arylfuran derivatives 7 in the Vilsmeier reaction.
Synthesis and proton NMR stereochemical study of 7,8,9‐substituted‐7,8‐dihydro‐4H,9H‐furo[2′,3′,4′:4,4a,5]‐naphth[2,1‐e][1,3]oxazin‐4‐ones
Authors: Sabie Rafa , Fillion Houda , Pinatel Henri , Fenet Bernard
Published: March 2009

7,8,9‐Substituted‐7,8‐dihydro‐4H,9H‐furo[2′,3′,4′:4,4a,5]naphth[2,1‐e][1,3]oxazin‐4‐ones were stereospecifically obtained as a single pair of enantiomers. Their relative trans configuration and the conformation of the dihydro oxazine ring were established by 1H nmr 2D NOESY experiments.
Synthesis of pyrrolo[2,3‐d]pyrimidine ribosides and their potential in chemotherapeutics
Authors: Eger Kurt , Grieb Gerlinde , Spätling Sabine
Published: March 2009

The synthesis of a number of 5,6‐dimethylpyrrolo[2,3‐d)pyrimidines substituted in position7with ribose, deoxyribose, respectively and their acyclic analogues is described and their potential in chemotherapeutics was tested. None of the compounds showed remarkable biological effects.
Synthesis of novel acyclonucleosides. Reactions of 1‐(2‐oxopropyl)pyridazin‐6‐ones
Authors: Choi Sam‐Yong , Shin Sung Chul , Yoon Yong‐Jin
Published: March 2009

Multi‐substituted‐1‐(1‐bromo‐2‐oxopropyl)pyridazin‐6‐ones 3, 4, multi‐substituted‐1‐(1,1‐dibromo‐2‐oxopropyl)pyridazin‐6‐ones 7, 8, and multi‐substituted‐1‐(3‐bromo‐2‐oxopropyl)pyridazin‐6‐ones 5, 6 were synthesized from the corresponding 1‐(2‐oxopropyl)pyridazin‐6‐ones 1, 2 by the selective bromination in acidic or neutral medium. And treatment of 1,1‐dibromo‐2‐oxopropyl derivatives 7, 8 with aqueous potassium carbonate gave the corresponding pyridazin‐6‐ones 9, 10 by the dealkylation. Reaction of 1 with methanolic potassium cyanide afforded only the corresponding 4‐methoxy derivative 11, whereas reaction of 2 with methanolic potassium cyanide gave 4‐methoxy derivative 12 and 2‐cyano‐2‐hydroxypropyl derivative 13. Reaction of 1 and 2 with hydroxylamine in methanol afforded the corresponding syn‐2‐hydroxyiminopropyl derivatives 14 and 15.
Cycloaddition‐elimination reactions of 4‐methyl‐5‐(substituted)‐imino‐Δ2‐1,2,3,4‐thiatriazolines with isocyanates
Authors: L'abbé Gerrit , Weyns Nancy , Sannen Ingrid , Delbeke Pieter , Toppet Suzanne
Published: March 2009

4‐Methyl‐5‐(substituted)imino‐1,2,3,4‐thiatriazolines 1 (R2 ≠ Me) undergo cycloaddition‐elimination reactions with isocyanates to yield 4‐methyl‐5‐(substituted)imino‐1,2,4‐thiadiazolidine‐3‐ones 5 via the thermodynamically less stable isomers 4. The latter have not been isolated, except for 4q which was shown to iso‐merize rapidly into 5q with phenylsulfonyl isocyanate. The reactions of 1 are accelerated by using less bulky R2 substituents and more electrophilic isocyanates, in accordance with the viewpoint that 1 reacts as a masked 1,3‐dipole. The products 4i‐n (= 5i‐n), derived from 1b, add isocyanates reversibly to give 2,3,4,5‐tetrahydro‐6aλ4‐thia‐1,3,4,6‐tetraazapentalene‐2,5‐diones 9i‐n, which have been isolated and characterized spectroscopically. Such compounds with a hypervalent sulfur atom thus occur as intermediates during the isomerization of 4 to 5 under the influence of isocyanates.
Syntheses of dibenzo[c,e][1,2]diselenin and related novel chalcogenide heterocyclic compounds
Authors: Murata Shizuaki , Suzuki Toshiyasu , Yanagisawa Akira , Suga Seiji
Published: March 2009

Reaction of 2,2′‐dilithio‐1,1′‐binaphthyl with selenium followed by air oxidation gives a mixture of dinaph‐thoselenophene and dimer and oligomers of 2,2′‐diseleno‐1,1′‐binaphthyl. 2,2′‐Dilithio‐1,1′‐biphenyl reacts with selenium to afford dibenzo[c,e][1,2]diselenin. Structures of the dimeric 2,2′‐diseleno‐1,1′‐binaphthyl and dibenzo[c,e][1,2]diselenin have been confirmed by X‐ray crystallographic analyses. Similar reaction of 2,2′‐dilithio‐1,1′‐binaphthyl with sulfur or tellurium gives a mixture of dinaphthothiophene and dinaphtho[2,1‐c:‐1′,2′‐e][1,2]dithiin or a mixture of dinaphthotellurophene and oligomer of 2,2′‐ditelluro‐1,1′‐binaphthyl, respectively. Dibenzotellurophene and oligomer of 2,2′‐ditelluro‐1,1′‐biphenyl are obtained from reaction of 2,2′‐dilithio‐1,1′‐biphenyl with tellurium.
Study of the transformation products of the oxime of 2,7‐dioxo‐3‐methyl‐5‐phenyl‐2,3,5,6‐tetrahydrocyclopenta[f]benzoxazole
Authors: Barbry Didier , Couturier Daniel , Abdellatifi Noureddine , Lesieur Daniel , Lespagnol Charles
Published: March 2009

Beckmann rearrangement of the title compound gave only a derivative of an isoquinoline structure and its catalytic hydrogenation afforded the cis isomer of 1‐amino‐3‐phenyl‐1,2‐dihydroindenes.
Synthesis of a phenylazo‐derivative of a 1,2,3‐thiadiazolium methylide. C‐13/N‐15 NMR characterization and crystal structure analysis
Authors: L'abbé Gerrit , Frederix Ann , Toppet Suzanne , Declercq Jean‐Paul
Published: March 2009

The N‐phenylhydrazone derived from 4‐methoxycarbonyl‐1,2,3‐thiadiazole‐5‐carbaldehyde 6 is methylated at the N‐3 position, yielding the mesoionic compound 8. The C‐13 and N‐15 nmr data, as well as the results from a crystal structure analysis, indicate that the molecule is best represented by the resonance forms 8A and 8B. Comparison is made with the previously synthesized thiadiazole derivative 2 which possesses thiapentalene characteristics.
Synthesis of 2‐aza analog of rosoxacin
Authors: Singh Baldev
Published: March 2009

Diazotization of 2‐nitro‐4‐(4‐pyridinyl)aniline (4) in hydrobromic acid gave the corresponding bromo derivative 5 which was treated with cuprous cyanide to give the benzonitrile derivative 6 which in turn was converted to 2‐nitroacetophenone derivative 9. Reduction of 9 followed by diazotization of the resulting amine 10 gave 7‐(4‐pyridinyl)cinnolin‐4(1H)‐one (11) which was subsequently converted to 1‐ethyl‐1,4‐dihydro‐4‐oxo‐7‐(4‐pyridinyl)cinnoline‐3‐carboxylic acid (14) in three steps.
2‐Aryloxazolo[4,5‐b]‐ et [5,4‐b]pyridines: Synthèse et acylation par substitution radicalaire
Authors: Flouzat C. , Guillaumet G.
Published: March 2009

La synthèse de diverses 2‐aryloxazolo[4,5‐b]‐ et [5,4‐b]pyridines 2 et 4 est décrite, respectivement à partir du 2‐amino‐3‐pyridinol et de la 2‐chloro‐3‐aminopyridine. L'acylation par substitution radicalaire des composés ainsi formés est ensuite étudiée et permet d'accéder à différentes 5‐acyl ou 7‐acyl‐2‐aryloxazolo[4,5‐b]‐et [5,4‐b]pyridines, avec des rendements satisfaisants.
Synthesis and properties of a maleimide fluorescent thiol reagent derived from a naphthopyranone
Authors: Yang Jun‐Rui , Langmuir Margaret E.
Published: March 2009

N‐(2‐Carbomethoxy‐9‐methoxy‐3‐oxo‐3H‐naphtho[2,1‐b]pyran‐10‐yl)maleimide 2 was designed and synthesized as a new maleimide fluorescent thiol reagent. The optical properties of 2 were investigated with and without the addition of glutathione, GSH. We have found 2 is twice as sensitive as DACM and is of comparable sensitivity to CPM for detection of thiols. The emission maximum for the GSH adduct of 2 is 513 nm which is at longer wavelength than the GSH adducts of both DACM and CPM.
Synthesis of 3,5‐disubstituted 1,2,4‐triazoles containing trimethoxyphenyl groups: Potential antagonists of platelet activating factor
Authors: Ares Jeffrey J. , Messier Renee J. , Kornecki Elizabeth
Published: March 2009

In an effort to develop a new class of Platelet Activating Factor antagonists, 3,5‐disubstituted 1,2,4‐triazoles containing trimethoxyphenyl groups have been synthesized. The synthesis of symmetrical triazoles5and6, as well as two methods of synthesizing unsymmetrical triazole7, are reported.
The stereochemical investigation of 8‐membered 1,3,6‐dioxazocines viaNMR
Authors: Nishiyama Tomihiro , Iwasaki Yoshiaki , Nishikawa Takeshi , Miyatake Shinji , Yamada Fukiko
Published: March 2009

The stereochemical properties of 2‐, 4‐, 7‐, and 8‐methyl substituted 5,6,7,8‐tetrahydro‐1,3,6‐dioxazocines have been investigated by their pmr and cmr spectroscopy. On the basis of the coupling constant and γ‐effects, the stereochemical structures are discussed.
Reaction of 4,5‐diamino, 5‐amino‐4‐glucosylamino and 4‐amino‐5‐glucosylaminopyrimidines with nitrous acid. synthesis, anticancer and anti‐aids activities of 8‐azapurines
Authors: Nogueras M. , Melguizo M. , Quijano M. L. , Sánchez A.
Published: March 2009

The reaction of the 4,5‐diamino, 5‐amino‐4‐glucosylamino and 4‐amino‐5‐glucosylaminopyrimidines 3a, 3b, 3c and 4 with nitrous acid is described. The 8‐azapurines 7a, 7c, 8 and the N‐nitrosoamino derivative 5 have been obtained. Some of these products were tested for anticancer and anti‐AIDS activity.
Synthesis and fluorescent properties of some heterobifunctional and rigidized 7‐aminocoumarins
Authors: Besson T. , Coudert G. , Guillaumet G.
Published: March 2009

Heterobifunctional fluorescent reagents of coumarin type are synthesized. They possess, in position 7, a rigidized or un‐rigidized amino group and, in position 3 or 4, a carboxylic function. The fluorescence characteristics of these compounds are described and compared with the 7‐amino‐4‐methylcoumarin. The influence of the relative freedom of rotation of the amino group or the position of the acid function on the fluorescence properties are also studied.
Synthesis of 1,3‐benzodioxoles, 1,3‐benzoxathioles and 1,3‐benzodithioles from allenic derivatives
Authors: Cabiddu Salvatore , Cadoni Enzo , Ciuffarin Ennio , Fattuoni Claudia , Floris Costantino
Published: March 2009

Benzo‐condensed five‐membered heterocyclic rings containing two heteroatoms have been synthesized starting from disubstituted benzenes and allenic derivatives. The structure of all products was corroborated by elemental analysis and ir and 1H nmr spectroscopy.
Research on nitrogen containing heterocyclic compounds.XVII. Synthesis of 8H‐diimidazo[1,5‐a:2′,1′‐c][1,4]benzodiazepine, a novel tetracyclic ring of pharmaceutical interest
Authors: Stefancich Giorgio , Artico Marino , Silvestri Romano
Published: March 2009

The synthesis of 8H‐diimidazo[1,5‐a:2′,1′‐c][1,4]benzodiazepine6, a novel nitrogen‐containing tetracyclic ring, is reported starting from 5H‐imidazo[2,1‐c][1,4]benzodiazepine7.Reaction of this compound with nitromethane and subsequent reduction of the obtained nitromethyl derivative8afforded 11‐aminomethyl‐10,11‐dihydro‐5H‐imidazo[2,1‐c][1,4]benzodiazepine9.Treatment of the latter compound with formaldehyde led to 1,2,3,3a‐tetrahydro‐8H‐diimidazo[1,5‐a:2′,1′‐c][1,4]benzodiazepine10, which was then oxidized to the title compound.
Oxidation of (7,16‐diethyl‐5,6,7,8,9,14,15,16,17,18‐decahydrodibenzo[b,i][1,4,8,11]tetraazacyclotetradecine)nickel(II) complexes
Authors: Hashimoto Mamoru , Sakata Kazunori
Published: March 2009

The oxidation reaction of two isomers of (7,16‐diethyl‐5,6,7,8,9,14,15,16,17,18‐decahydrodibenzo[b,i]‐[1,4,8,11]tetraazacyclotetradecine)nickel(II) diperchlorate and/or dichloride (NiL1X2 (X = ClO4, Cl)) in methanol in air under atmospheric pressure leads to the production of (7,16‐diethyl‐5,6,7,8,9‐pentahydrodibenzo‐[b,i][1,4,8,11]tetraazacyclotetradecinato)nickel(II) complexes (NiL2X). Proton and 13C nmr spectra suggest that NiL2X is formed by partial oxidation from a macrocyclic skeleton of NiL1X2. The dehydrogenation of NiL1X2 does not occur at symmetric positions such as d‐ and k‐positions of the macrocyclic skeleton but at unsymmetrical positions such as d‐ and f‐positions. Treatment of NiL1X2 and/or NiL2X in a methanol solution with an excess of bases in air gives (7,16‐diethyldibenzo[b,t][1,4,8,11]tetraazacyclotetradecinato)nickel(II) (NiL3).
Mass spectrometry of 3,4‐dihydroquinazolin‐4‐ones of pharmaceutical interest. Part 3. Electron ionization mass spectra of 2‐substituted‐3‐(5′‐pyrazolyl)‐4(3H)‐quinazolinones
Authors: Ferrugia Mirella , Bajardi Maria Luisa , Ceraulo Leopoldo , Plescia Salvatore
Published: March 2009

The fragmentation reactions induced by electron impact of eighteen title compounds has been investigated with the aid of low beam energy spectra (14 eV, nom. value), metastable ion detection, high resolution measurements and labelling experiments. The loss of the 4‐carbonyl oxygen together with the 3‐substituent, which constitutes a characteristic fragmentation route of 3‐aryl and 3‐heteroaromatic substituted‐4(3H)‐quinazolinones, is again observed, but the presence of a carboxyethyl group at the 4′‐position of the pyrazole ring is responsible of an anomalous loss of 47 daltons from the molecular ion. Lastly, a comparison with the previously described behaviour of 3‐(5′‐isoxazolyl) derivatives was carried out.
Study of the diazoimine/triazole equilibria for substituted thiazoles and thiadiazoles
Authors: L'Abbé Gerrit , Luyten Ingrid , Toppet Suzanne
Published: March 2009

Several diazomethyl and diazoester substituted thiazoles and thiadiazoles were prepared and their ring/chain equilibria studied by nmr spectroscopy. The diazomethyl derivatives 17a,b,d and 19a exist predominantly or exclusively in the triazole form. Ring‐opening is promoted by introducing an ester group at the diazo function (17c,e, 19b, 21) or by changing thiazoles for thiadiazoles in the following order: thiazole < 1,3,4‐thiadiazole < 1,2,4‐thiadiazole. The diazoimine/triazole equilibria are also shifted towards the diazo form by raising the temperature and by using less polar solvents in the order: dimethyl sulfoxide < acetonitrile < chloroform < benzene. The ir spectra (potassium bromide discs) of the compounds indicate that they all, except 21, exist in the crystalline state in the triazole form.
NMR studies of bond orders in heteroaromatic systems
Authors: Gready Jill E. , Hatton Paul M. , Sternhell Sever
Published: March 2009

Fifty‐seven values for the ortho‐benzylic coupling constant 4JMeCCH (henceforth denoted as 4JOB) were obtained for a variety of heteroaromatic systems. It was shown that a good correlation exists between 4JOB when the methyl group is not α to the heteroatom and the SCF‐MO bond order. This method can therefore be used as an experimental means of determining bond orders in heteroaromatic systems. An examination of bond alternation in thirteen heteroaromatic systems has given a measure of relative “degree of aromaticity” for a larger number of systems than previously reported by any single method.
Synthesis and crystal structure analysis of a 6aλ4‐thia‐1,2,3,4,6‐pentaazapentalene
Authors: L'abbé Gerrit , Albrecht Ernestine , Feneau‐Dupont J. , Declercq J.‐P.
Published: March 2009

6aλ4‐Thia‐1,2,3,4,6‐pentaazapentalenes 3 are conveniently prepared by reacting 5‐imino‐Δ3‐1,2,4‐thiadi‐azolines 2 with aromatic diazonium tetrafluoroborates in the presence of pyridine. The first crystal structure analysis of this class of compounds 3g is described and shows properties characteristic of a thiapentalene structure; i.e. long N‐S‐N bonds (1.85 and 1.975 Å) in a nearly linear arrangement (164°) and comprising a heterobicycle which is strictly planar.
Acetylenic chemistry. Part 24. N‐vinylation of N‐H acid heterocycles
Authors: Reisch Johannes , Dittmann Stefan
Published: March 2009

The vinylation of 9H‐carbazole (1), 1H‐indole (3a), and 1H‐pyrrolo[2,3‐b]pyridine (3b) with propiolic acid ethyl ester resulting in N‐acrylic esters is reported here.
The reactivity of 3‐methyl‐5‐phenylisothiazole with carbonyl compounds
Authors: Alberola Angel , Calvo Luis , Rodríguez Rodríguez M. Teresa , Carmen Sañudo M.
Published: March 2009

The reactivity of 3‐methyl‐5‐phenylisothiazole with carbonyl compounds in the presence of n‐butyllithium and the system lithium isopropylcyclohexylamide‐N,N,N',N'‐tetramethylethylendiamine (LICA‐TMEDA) is studied. n‐Butyllithium is found to lead to higher yields of the hydroxy derivatives of the isothiazole compound than LICA‐TMEDA. Ring opening products are not detected under the reaction conditions used.
Electrophilic benzylation of the pyridine ring. Action of benzyl chlorides on 2‐amino and 2‐benzylaminopyridine
Authors: Kowalski Piotr
Published: March 2009

The reaction of 2‐aminopyridine as well as 2‐benzylaminopyridine hydrochloride with benzyl chlorides used in molar ratio of 1:2 and 1:1 respectively and carried out at 250° leads via 2‐benzylamino‐5‐benzylpyri‐dines to 2‐amino‐5‐benzylpyridines as the final products. The formation of 2‐benzylamino‐5‐benzylpyridines did not occur in the direct C‐benzylation reaction of the 2‐benzylaminopyridine ring with the use of benzyl chloride. Its formation takes place via the intermediate state of 2‐(N,N‐dibenzylamino)pyridinium and 1‐benzyl‐2‐benzylaminopyridinium chlorides for which the solvent separated ion‐molecule form is proposed. Interaction of the ingredients of the intermediate state i.e., benzyl cation and 2‐benzylaminopyridine, leads in an electrophilic mechanism to the formation of 2‐benzylamino‐5‐benzylpyridine hydrochlorides. Thermolysis of the aminomethylene bond in 2‐benzylamino‐5‐benzylpyridine hydrochlorides leads to the final 2‐amino‐5‐benzylpyridines.
Reaction of nitriles under acidic conditions. Part VII. Study on the reaction of o‐aminonitriles with cyanamides to synthesize 2,4‐diaminothieno[2,3‐d]pyrimidines
Authors: Shishoo C. J. , Jain K. S.
Published: March 2009

The reaction of N‐arylcyanamides with thiophene o‐aminonitriles under the influence of dry hydrogen chloride gas yields a mixture of two products. The major product has been identified as 2‐amino‐3‐aryl‐4‐iminothieno[2,3‐d]pyrimidine and the minor as 2‐amino‐3‐arylthieno[2,3‐H]pyrimidin‐4(3H)‐one.
Identification of a 4H‐benz[f]indole by‐product from the friedel‐crafts‐based synthesis of benzoylpyrrole calcium channel activators
Authors: Huber Edward W. , Barbuch Robert J. , Dalton Christopher R. , Kane John M. , Velayo Nelson L.
Published: March 2009

9,9a‐Dihydro‐2,9a‐dimethyl‐4‐oxo‐4H‐benz[f]indole‐3‐carboxylic acid, methyl ester was formed in varying amounts from the Friedel‐Crafts‐based synthesis of benzoylpyrrole calcium channel activators. The structure of this by‐product was determined using two‐dimensional long‐range1H‐13C heteronuclear correlated and INADEQUATE nmr techniques.
Preparation of 4‐substituted 1,3‐oxathiolan‐5‐ones via the sulphenium ion intermediate generated by the pummerer rearrangement
Authors: Frechina J. V. , Palanca P. , Picher T. , Sanz V. , Ramirez J. A.
Published: March 2009

4‐Substituted 1,3‐oxathiolan‐5‐ones have been synthesized via the Pummerer rearrangement from the S‐oxide of the parent molecule. The 4,5‐dione is obtained in the presence of pyridine N‐oxide.
Synthesis of methyl derivatives of new polycyclic systems of 4H‐furo[3,2‐g]pyrrolo[3,2,1‐ij]quinolin‐4‐one, of 1H,5H‐ and 3H,5H‐benzofuro[5,6,7‐ij]quinolizin‐5‐one
Authors: Rodighiero P. , Bandoli G. , Chilin A. , Manzini P. , Guiotto A.
Published: March 2009

The synthesis of new tetracyclic 4H‐furo[3,2‐g]pyrrolo[3,2,1‐ij]quinolin‐4‐ones, 15–17, 1H,5H‐benzofuro[5,6, 7‐ij]quinolizin‐5‐ones, 18–20, and 3H,5H‐benzofuro[5,6,7‐ij]quinolizin‐5‐ones, 21–23 is described. The planarity of the structure of benzofuroquinolizin‐5‐one 18 was determined by X‐ray single‐crystal analysis.
Structural elucidation of an oxazolo[5,4‐b]pyridine: An alternative cyclization product related to nevirapine
Authors: Norman Mark H. , Minick Douglas J. , Martin Gary E.
Published: March 2009

An unexpected cyclization product was isolated in the final step of the synthesis of nevirapine, a non‐nucleoside inhibitor of HIV‐1 reverse transcriptase. Based on infrared spectrometry, mass spectrometry, and a number of two‐dimensional nmr experiments, the structure of this product was assigned to be 2‐((2′‐cyclopropylamino)‐3′‐pyridyl)‐7‐methyloxazolo[5,4‐b]pyridine, 9. Results of a single crystal X‐ray analysis confirmed this structural assignment. This product arises from cyclization of N‐(2‐chloro‐4‐methyl‐3‐pyridyl)‐2‐(cyclopropylamine)‐3‐pyridinecarboxamide, 8, by displacement of the chlorine with the amide carbonyl oxygen. A competitive reaction occurs when 8 is deprotonated prior to cyclization to form nevirapine, 11‐cyclopropyl‐5,11‐dihydro‐4‐methyl‐6H‐dipyrido[3,2‐b:2′,3′‐e][1,4]diazepin‐6‐one, 2.
Synthesis of 5,6‐ and 5,7‐dichloro‐3‐methyl‐4H‐1,4‐benzothiazines and their conversion into sulfones
Authors: Gupta R. R. , Saraswat Vandana , Gupta Vandana , Rajoria C. M. , Gupta Archana , Jain Mukesh
Published: March 2009

A one pot synthesis of 5,6‐ and 5,7‐dichloro‐3‐methyl‐4H,4‐benzothiazines is reported by the condensation and oxidative cyclization of 2‐amino‐3,4‐ and 3,5‐dichlorobenzenethiols with β‐dicarbonyl compounds. The oxidation of 4H‐1,4‐benzothiazines by 30% hydrogen peroxide in glacial acetic acid has provided the corresponding sulfones. The effect of the conversion of the sulfide linkage to sulfone is discussed. The structure of all the newly synthesized compounds has been confirmed by elemental analysis and spectral studies.
Synthesis of imidazo[4,5‐b]quinoxaline 3‐oxides from reactions of furazano[3,4‐b]quinoxaline 1‐oxides with nitrones and diazo compounds
Authors: Gallos John K. , Malamidou‐Xenikaki Elizabeth , Lianis Pygmalion S. , Spyrou Labros I.
Published: March 2009

The title compounds are prepared in good yields by simple procedures from readily available starting materials. They can be easily O‐methylated by methyl iodide or deoxygenated by triphenylphosphine.
Methylation of 5‐Phenyl‐1,4‐benzodiazepin‐2‐one derivatives with N,N‐dimethylformamide‐dimethyl acetal
Authors: Pinto Julia C. , Fryer R. Ian
Published: March 2009

A novel method for N‐methylation of the cyclic amide in the 1,4‐benzodiazepine ring system is presented. Methods traditionally used involve treatment of the 1,4‐benzodiazepinone anion with an alkyl halide. It has been demonstrated that these derivatives can be methylated on the amide nitrogen atom by use of dimethyl‐formamide dimethyl acetal which acts as both reagent and solvent for the reaction.
Novel oxidations of 1,3‐disubstituted indoles
Authors: Morales‐Ríos Martha S. , Bucio‐Vásquez Ma. Alvina , Joseph‐Nathan Pedro
Published: March 2009

A study of oxidation versus nitration of 1,3‐disubstituted indole derivatives with nitric acid in acetic acid was carried out. Oxidation of methyl and ethyl 2‐cyano‐2‐(1‐alkoxycarbonyl‐1H‐indol‐3‐yl)acetates 1 and 2 under the above conditions gave rise to novel functionalized 2‐hydroxyindolenines as single products possessing the Z‐configuration, 8 and 10, respectively. The structure of 10 was determined by an X‐ray analysis. In contrast, 1‐methoxycarbonyl‐1H‐indol‐3‐acetonitrile (3) was nitrated to the corresponding 6‐nitroindole derivative 11, whereas the reaction of ethyl 2‐cyano‐2‐(1‐methyl‐1H‐indol‐3‐yl)acetate (4) with nitric acid effected an oxidative nitration to provide the corresponding ethyl Z‐5‐nitroisatyliene cyanoacetate (12), which in solution isomerized to the E isomer.
Synthesis and complexing properties of bis‐crown ethers incorporating benzo‐15‐crown‐5 and metallocene
Authors: Izumi Taeko , Oohashi Satoshi , Tate Yasuhiro
Published: March 2009

Bis‐crown ethers in which the benzo‐15‐crown‐5 units were linked to 1,1′‐positions of metallocene (M = Fe or Ru) with amide, ester, or CC bonds were synthesized. Complexing ability of the compounds with alkali, alkali earth, and transition metal cations were measured by the solvent extraction method. The results showed that these crown ethers had high affinity toward alkali metal cations (Li+, Na+, K+, and Rb+) and heavy‐metal cations (Ag+ and Tl+). The difference of complexing ability for metal cations between ferrocene and ruthenocene derivatives could not be detected significantly. The extractability of metallocene‐bis‐crown ethers for metal cations was more larger than that of the corresponding mono‐crown ethers, and irregular increments of extractability were explained by assuming the existence of a mixture of 1:1 and 2:1 complexes.
Cyclic β‐enamino esters dialkylation: A new route to cyclic imines
Authors: Eugene Marina , Celerier Jean‐Pierre , Ronzani Nello , Lhommet Gérard
Published: March 2009

The bis‐alkylation of cyclic β‐enamino esters has been investigated, and exploited as a general method of synthesis of cyclic monosubstituted imines.
Synthesis of 5‐phenyl‐2,3,8,9‐tetramethoxy‐11H‐indeno[1,2‐c]isoquinoline
Authors: Ibañez Adriana F. , Martinez Andrea R. , Iglesias Graciela Y. Moltrasio
Published: March 2009

A novel approach to the title compound 10 starting with a conveniently available cinnamic acid is proposed. It involves a Friedel‐Crafts reaction followed by the synthesis of the amide and subsequent cyclodehydration via a Bischler‐Napieralski reaction.