bluuebunny/crossref_metadata_2025 huggingface dataset:
The synthesis of 1‐haloalkyl‐1,3,4,5‐tetrahydro‐2‐benzoxepins
Authors: Tenbrink Ruth E. , Mccall John M.
Published: March 2009

Short, efficient routes to several 7,8‐dimethoxy‐1‐haloalkyl‐1,3,4,5‐tetrahydro‐2‐benzoxepins were developed. These benzoxepins were prepared by the Lewis acid catalyzed condensation of the acetals of chloropropionaldehyde or bromoacetaldehyde with 3‐(3,4‐dimethoxyphenyl)‐1‐propanol. This condensation was facilitated by methyl substitution on the propanol. In an alternate route, ethyl 3‐(3,4‐dimethoxyphenyl)propanoate was acylated with 3‐chloropropionyl chloride. The adduct was reduced with lithium aluminum hydride. The resultant 3‐[2‐(3‐chloro‐1‐hydroxypropyl)‐4,5‐dimethoxyphenyl]propanol was dehydrated to the corresponding tetrahydrobenzoxepin. By these two general routes, 7,8‐dimethoxy‐1,3,4,5‐tetrahydro‐2‐benzoxepins were produced which were substituted by hydrogen or methyl at benzoxepin C‐4 and chloroethyl or bromomethyl at benzoxepin C‐1.
Synthesis of 4‐acyl‐2,3‐dihydro‐4H‐1,4‐oxazines
Authors: Nicola Massimo , Gaviraghi Giovanni , Pinza Mario , Pifferi Giorgio
Published: March 2009

The synthesis of 4‐acyl‐2,3‐dihydro‐4H‐1,4‐oxazines (6a‐h) via acid dehydration of 4‐acyl 2‐ and 3‐morpholinols is described. During dehydration of 2‐morpholinols 3d,e, N‐alkylisoquinolones 7a‐e were also isolated.
An improvement in the synthesis of ethyl pyrimidinecarbamates
Authors: Auzou Gilles , Rips Richard
Published: March 2009

It is demonstrated that N‐(ethoxycarbony])pyridinium chloride (3) is the reactive agent in the synthesis of 4‐ethoxycarbonylamino‐2,6‐dimethylpyrimidine (1). A good yield (80%) of 1 may be obtained by the condensation of 3 with excess 4‐amino‐2,6‐dimethylpyrimidine using pyridine or dimethylformamide as the solvent. A method allowing for the preparation of 4‐ethoxycarbonylamino‐x‐hydroxypyrimidines via the same process is offered.
Anti‐configuration of the N = N bond in azobilirubin pigments
Authors: Salmón Manuel , Rubio Manuel , Cetina Raul
Published: March 2009

The conformational and internal energy barriers for rotation of the phenylazo group in azobilirubin pigments were determined by the PCILO method. The calculations showed a restricted rotation of the azo group at 180–300° dihedral angle.
Cyanogen bromide as a reagent for lactone formation. Preparation of dibenz[b,e][1,4]oxazepin‐11‐(5H)ones
Authors: Kim Dong Han
Published: March 2009

The treatment of N‐(2‐hydroxyphenyl)anthranilic acids with cyanogen bromide in the presence of triethylamine gave dibenz[b,e][1,4]oxazepin‐11‐(5H)ones in good yields.
Synthesis and reactivity of N‐[α‐acetoxy)‐4‐pyridylmethyl]‐3,5‐dimethylbenzamide
Authors: Braña Miguel F. , Rodriquez María L. LÓPez
Published: March 2009

The synthesis of N‐[(α‐acetoxy)‐4‐pyridylmethyl]‐3,5‐dimethylbenzamide (4) and its reactivity are described. Since the acetoxy is a good leaving group, 4 gives SN processes easily.
Phenalenones. IV. Heterocycles from 3‐hydroxyphenalenone (I)
Authors: Kuroki Masatane , Terachi Yasuhito , Tsunashima Yutaka
Published: March 2009

3‐Hydroxyphenalenone reacts with o‐disubstituted benzenes (substituents: NH2, OH, CH2OH and SH), aliphatic and aromatic aldehydes to give the various heterocyclic compounds which are fused with phenalene ring. These reactions resemble those of 1,3‐cyclohexanediones in many respects.
Synthesis of s‐triazolo[4,3‐b]pyridazine C‐nucleosides
Authors: Legraverend Michel , Bisagni Emile , Lhoste Jean‐Marc
Published: March 2009

A one step synthesis of s‐triazolo[4,3‐b]pyridazine using 3‐chloro‐6‐hydrazinopyridazine and an appropriate thioformimidate is described. Applying this procedure to 5‐O‐benzoyl‐1‐benzylthio‐1‐formimidate‐D‐ribofuranose, 5′ benzoyl‐6‐chloro‐3β‐D‐ribofuranosyl‐s‐triazolo[4,3‐b]pyridazine was obtained. Substitutions of chlorine by nucleophilic reagents afforded some derivatives of a new series of C‐nucleo‐sides. Structural determination including anomeric configuration assignment is discussed based mainly on 1H nmr spectroscopy.
Chemistry of 1,2,3‐thiadiazole. IV. Synthesis of [1]benzoxepino‐[3,4‐d][1,2,3]thiadiazole, [1]benzothiepino‐[3,4‐d][1,2,3]thiadiazole, [1]benzoxepino[4,3‐d][1,2,3]thiadiazole, [1]benzoxepino[4,3‐d]oxazole and [1]benzoxepino[4,3‐d]oxazole. Four novel heterocycles
Authors: Shafiee A. , Kiaeay G.
Published: March 2009

Starting from the readily available 4‐bromomethy‐5‐carbethoxy 1,2,3‐thiadiazole (V), 5‐bromomethy‐4‐carbethoxy‐1,2,3‐thiadiazole (IX) and ethyl 2‐aryl‐5‐bromomethyloxazole‐4‐carboxylate (XIV), 4,10‐dihydro‐10‐oxo[1]benzoxepino[3,4‐d][1,2,3]thiadiazole (Ia), 4,10‐dihydro‐10‐oxo[1]benzothiepino[3,4‐d][1,2,3]thiadiazole (Ib), 4,10‐dihydro‐4‐oxo[1]benzothiepino[4,3‐d] [1,2,3]thiazole (II), 2‐aryl‐4,10‐dihydro‐4‐oxo[1]benzoxepino[4,3‐d]oxazoles (XIXa‐XIXc) and 2‐aryl‐4,10‐dihydro‐4‐oxo[1]benzothiepino[4,3‐d]oxazoles (XIXd‐XIXf) were prepared.
Reaction of the pyrazinium ion having aryl and cyano groups with hydride reagents or hydroxide ion
Authors: Hirano Hadeki , Tada Masaru
Published: March 2009

Reduction of 3‐cyano‐5‐(3,4‐dimethoxyphenyl)‐1‐methylpyrazinium ion by the hydride reagents such as sodium borohydride or Hantzsch ester gave the 1,6‐dihydropyrazine derivative, and the 1,4,5,6‐tetra‐hydropyrazine derivative on further reduction. Addition of hydroxide ion to the pyrazinium ion gave mainly a 6‐hydroxy‐pseudobase, accompanied by the minor formation of a 2‐hydroxy‐pseudobase. Photoreaction of the pseudobase mixture gave a product from the major pseudobase but thermal transformation gave another product from the minor pseudobase.
Reissert compound studies. XLII. Synthesis and reactions of the 3,4‐dihydro‐β‐carboline reissert compound and observations on α, β, and γ‐carbolines
Authors: Veeraraghavan Seshadri , Popp Frank D.
Published: March 2009

3,4‐Dihydro‐β‐carboline and benzo[α]‐γ‐carboline yielded Reissert compounds. The 3,4‐dihydro‐β‐carboline Reissert compound, through its acid‐ and base‐promoted reactions, was found to be a very useful intermediate in the synthesis of several β‐carboline derivatives including tetracyclic compounds. Reaction of the 3,4‐dihydro‐β‐carboline Reissert compound with dichlorodicyanobenzoquinone (DDQ) resulted in the formation of l‐cyano‐β‐carboline thereby providing the first example of an oxidation of a Reissert compound with DDQ. α‐, β‐ and γ‐Carbolines failed to form Reissert compounds under a wide variety of conditions. 7‐Azaindole also failed to yield a Reissert compound.
2‐Imidazolines. V. The formation of hydroxy derivatives in the synthesis of 4,5‐diamino‐2‐imidazolines from 1,2‐diimmonium salts and amidines
Authors: Malnati Maria Luisa , Stradi Riccardo , Rivera Elisabetta
Published: March 2009

During the preparation of 1‐aryl‐ and 1‐acyl‐4,5‐dipiperidino‐4,5‐dihydroimidazoles (1) from diimmonium salts (3), derivatives in which one of the piperidino groups was substituted by an hydroxy group were often isolated. The structure and the genesis of these compounds are discussed.
Synthesis of 6‐benzyl‐ and 6‐phenethyl‐2,4‐diamino‐5,6,7,8‐tetrahydropyrimido[4,5‐d]pyrimidines
Authors: Delia Thomas J. , Sami Salah M.
Published: March 2009

The preparation of ten aralkyl derivatives of 2,4‐diamino‐5,6,7,8‐tetrahydropyrimido[4,5‐d]pyrimidines (6) has been accomplished. The title compounds were prepared in a simple one step reaction from 2,4,6‐triaminopyrimidine (4), formaldehyde (2), and either substituted benzylamines (1a‐d) or substituted phenethylamines (1e‐j). This modified Mannich reaction has been shown to be a general method for such derivatives. Elemental analysis, 1H nmr and mass spectral data have confirmed the proposed structures. None of the compounds exhibited either antimalarial or antitrypanosomal activity.
Synthesis of pyrimidine acyclonucleosides
Authors: Abrams H. M. , Ho L. , Chu S. H.
Published: March 2009

Nucleoside analogues of uridine, 5‐bromo‐, 5‐iodo‐, and 5‐fluorouridines, thymidine and cytidine were prepared by condensing appropriately substituted 2,4‐dimethoxypyrimidines with an acyclic side chain in the form of a benzoylated halo‐ether, and subsequent removal of the protecting benzoyl group in base. The 2′‐O‐p‐tosylates of these nucleoside analogues could then be modified to 2′‐halo‐, azido‐, and amino derivatives. Many of these compounds are competitive inhibitors of uridine phosphorylase in vitro, the most active being 5‐methyl‐1‐(2′‐hydroxyethoxymethyl)uracil.
Synthesis of imidazolidin‐4‐ones and their conversion into 1,4‐benzodiazepin‐2‐ones
Authors: Hannoun M. , Žinić M. , Kolbah D. , Kajfež F. , BlaŽević N.
Published: March 2009

α‐Haloacetanilides Ia‐e react with hexamine in ethanol giving the bisimidazolidin‐4‐one derivatives IIa‐e, which hydrolize, in acidic media into the corresponding mono‐imidazolidin‐4‐ones IIIa‐e. The compounds IIa‐d were converted into 1,4‐benzodiazepin‐2‐ones, under different conditions and in the presence of a variety of agents. The yields were between 50 and 100%.
13C‐Nmr spectra of anhydro‐3‐mercapto‐5‐pyrazinyl‐1,2,4‐triazolium hydroxides
Authors: Shutske Gregory M. , Agnew Marc N.
Published: March 2009

The complete assignment of the 13C‐nmr spectra of some anhydro‐3‐mercapto‐5‐pyrazinyl‐1,2,4‐triazolium hydroxides (1) is reported. For purposes of comparison the spectra of some isomeric triazole‐3‐thiones (2) are also reported. Positions C‐3 and C‐5 of the triazole ring and 2′ of the pyrazine moiety were found to be characteristic of each group of compounds.
The synthesis, configuration, and conformation of cis‐ and trans‐3‐amino‐3,4‐dihydro‐1‐hydroxy‐4‐methylcarbostyrils and other configurationally related compounds
Authors: Mccord Tommy J. , Smith Sherrel C. , Tabb David L. , Davis Alvie L.
Published: March 2009

The cis‐ and trans‐3‐amino‐3,4‐dihydro‐1‐hydroxy‐4‐methylcarbostyrils (Ia and Ib) were synthesized by catalytic hydrogenation of erythro‐ and threo‐α‐amino‐β‐(o‐nitrophenyl)butyric acid hydrochlorides, IIIa and IIIb, respectively, under acidic conditions. The free bases of IIIa and IIIb were catalytically hydrogenated under neutral conditions to yield the erythro‐ and threo‐α‐amino‐β‐(o‐aminophenyl)butyric acids (VIa and VIb), which were converted by acidification to their corresponding lactams, cis‐ and trans‐3‐amino‐3,4‐dihydro‐4‐methylcarbostyrils, IIa and IIb. The erythro and threo isomers of α‐amino‐β‐(o‐nitrophenyl)‐butyric acid were prepared and separated by liquid chromatography via a diastereomeric mixture of (V) of methyl α‐acetamido‐β‐(o‐nitrophenyl)butyrates. The configurations and conformational assignments of the cyclic hydroxamic acids Ia and Ib were first established by analysis of the proton nmr spectra. In turn, the configurations of the o‐nitroaromatic amino acids IIIa and IIIb were assigned as well as the other structurally related compounds (VIa, VIb, IIa and IIb) derived therefrom.
Mass spectra of 5‐fluorouracil derivatives. N‐1‐substituted sulfonyl derivatives
Authors: Marunaka Teruyoshi
Published: March 2009

The electron impact mass spectra of 1‐sulfonyl substituted derivatives of 5‐fluorouracil were investigated. The substituents were CH3SO2 (compound I), CH3(CH2)3SO2 (II), C6H5SO2 (III) and p‐CH3C6H4SO2 (IV).
1,2,4‐Triazines. II. A new general synthesis of 3,4‐dihydro‐1,2,4‐triazin‐5‐(2H)ones
Authors: Sanemitsu Yuzuru , Nakayama Yoskinori , Shiroshita Masao
Published: March 2009

3,4‐Dihydro‐1,2,4‐triazin‐5‐(2H)ones were prepared by the reduction of 3‐methylthio‐1,2,4‐triazin‐5‐(2H)‐ones with sodium borohydride in dimethylformamide. The synthesis appears to be general.
Synthesis of some 1‐substituted‐3‐or‐5‐styrylpyrazoles
Authors: Deshayes Christian , Chabannet Mickel , Gelin Suzanne
Published: March 2009

The synthesis of the title compounds by the Wittig‐Horner reaction is described, using the 3‐or‐5‐hydroxymethylpyrazole derivatives as precursors.
Synthesis of oxetanes by photoaddition of carbonyl compounds to thiophene derivatives
Authors: Rivas C. , Pacheco D. , Vargas F. , Ascanio J.
Published: March 2009

2,3‐Dimethyl, 3,4‐dimethyl and 2,3,5‐trimethylthiophene were synthesized and subjected to interaction with excited benzophenone. 2,3‐Dimethylthiophene affords an oxetane in good yield. These experiments were carried out in order to generalize this reaction which thus far has only been successful with 2,5‐dimethylthiophene.
Rearrangement of 2‐aminofuro[3,2‐b]pyridine‐3‐carboxylic esters
Authors: Desideri Nicoletta , Manna Fedele , Stein Maria Luisa
Published: March 2009

Ethyl 2‐aminofuro[3,2‐b]pyridine‐3‐carboxylate rearranges with sodium ethoxide in ethanol to 2‐oxo‐3‐cyano‐2,3‐dihydro[3,2‐b]furopyridine; the corresponding p‐nitrophenyl ester undergoes the same rearrangement by dilute aqueous sodium hydroxide. In the first case it was possible to isolate the labile intermediate, which was shown to be the hemiacetal of the above mentioned cyanolactone.
Photosensitized oxidation of furans. III. Comparison between photochemically and thermally generated singlet oxygen oxidation of 3‐methoxycarbonyl‐2‐methyl‐5‐phenylfuran
Authors: Graziano M. L. , Iesce M. R. , Carli B. , Scarpati R.
Published: March 2009

Thermal conversion of furan endo‐peroxide I, obtained by photosensitized oxidation of furan II, yields very similar results to those of the oxidation of the furan II by thermally generated singlet oxygen, showing that also in the latter case the endo‐peroxide I is the key intermediate. A mechanistic interpretation of the furan II‐singlet oxygen reaction is reported.
Studies on v‐triazoles. Part II. Synthesis of 9‐oxo‐1H,9H‐benzopyrano[2,3‐d]‐v‐triazoles
Authors: Buckle Derek R. , Outred D. James , Rockell Caroline J. M.
Published: March 2009

Ethyl 1‐benzyl‐5‐chloro‐v‐triazole‐4‐carboxylate (3) undergoes facile nucleophilic displacement of the halogen atom with phenoxide ion to yield aryloxytriazolecarboxylates 4 which debenzylate under hydrogenolytic conditions to N‐H triazoles 7. Saponification and cyclization with either polyphosphoric acid or phosphoric oxide in methanesulphonic acid leads to the novel 9‐oxo‐1H,9H‐benzopyrano[2,3‐d]‐v‐triazole system 9, members of which have potential as antiasthmatic agents.
Synthesis of 2,5‐disubstituted oxazoles from aldehydes and N‐(tosylmethyl)imino synthons. Application to the synthesis of pimprinine analogues
Authors: Houwing Hendrik A. , Wildeman Jurjen , Van Leusen Albert M.
Published: March 2009

A series of N‐(tosylmethyl)imino compounds [TosCH2NC(L)A] has been applied to a new base‐induced, one‐operational synthesis of 2,5‐disubstituted oxazoles from aromatic aldehydes. For substituent A of the imino compounds, which becomes the 2‐substituent in the oxazoles, has been chosen methoxy, methyl and phenyl. The new method has been used also to synthesize seven pimprinine analogues, i.e., 5‐(‐3)indolyl)oxazoles.
Chemistry of the phenoxathiins and isosterically related heterocycles. XIX.. The crystal and molecular structure of 1‐N,N‐dimethylamino‐2,3‐diazaphenoxathiin: An interesting product isolated from the reaction of o‐mercaptophenol with 3,4,5‐trichloropyridazine in N,N‐dimethylformamide
Authors: Womack Charles H. , Turley James C. , Martin Gary E. , Kimura Michio , Simonsen Stanley H.
Published: March 2009

The isolation of 1‐N,N‐dimethylamino‐2,3‐diazaphenoxathiin and its molecular structure as determined by X‐ray crystallography are described. The existence of a potential non‐bonded interaction between the lone pair of electrons of the dimethylamino group nitrogen and sulfur atom are also discussed.
Application of the partitioning of energy in the mndo method to the study of the basicity of imidazole, pyrazole, oxazole, and isoxazole
Authors: Olivella Santiago , Vilarrasa Jaume
Published: March 2009

The technique of energy partitioning of Fischer and Kollmar has been extended to the MNDO SCF‐MO method and used in an effort to ascertain the main factors which determine the greater basicity of imidazole and oxazole relative to pyrazole and isoxazole, respectively. The importance of the different degree of destabilization of the five‐membered ring π bonding in these azoles upon protonation is specially emphasized in relation to their relative basicity. Furthermore, it is found that the degree of destabilization of the π bonding can be ascribed to the amount of π electron charge density localized on the heteroatoms after protonation. An interpretation for this result is given in terms of the mutual electrostatic field effect due to the cores of the nearest‐neighbor atoms.
Some reactions of 4‐[(2′,3′‐diphenyl‐6′‐methoxy‐5′‐benzofuranyl)‐methylene]‐ and 4‐[(2′,3′‐diphenyl‐5′‐methoxy‐6′‐benzofuranyl)‐methylene]‐2‐phenyloxazolin‐5‐one
Authors: Hishmat O. H. , Abd El Rahman A. H. , Moawad M. I.
Published: March 2009

2,3‐Diphenyl‐5‐formyl‐6‐methoxybenzofuran was reacted with hippuric acid to give 4‐[(2′,3′‐diphenyl‐6′‐methoxy‐5′‐benzofuranyl)methylene]‐2‐phenyloxazolin‐5‐one. The above mentioned oxazolone yielded 2,3‐diphenyl‐6‐methoxybenzofuranylacetic acid by reaction with hydrazine hydrate, nitrous acid, benzene followed by acid hydrolysis. The reactions of the oxazolone with hydroxylamine hydrochloride and primary or secondary amines were also investigated.
Nucleophilic substitution at sulphonyl sulphur part 3. Hydrolysis of substituted thiophene‐2‐sulphonyl chlorides catalysed by silver nitrate and silver nitrite salts
Authors: Ballistreri Francesco P. , Tomaselli Gaetano A.
Published: March 2009

Hydrolysis reactions of substituted thiophene‐2‐sulphonyl chlorides (5‐methyl, 5‐H, 5‐chloro, 5‐nitro) catalysed by silver nitrate and silver nitrite salts have been studied in water at 25°. Salt effects by potassium nitrate, sodium perchlorate and mercuric bromide have also been investigated. For the catalysis effected with silver nitrate, the pseudo‐first order rate constants depend on the first power of silver ion concentration, while nitrate anion is not involved in the transition state. The corresponding curved Hammett plot suggests a transition state with a partially developed sulphonylium character. With silver nitrite, the rate dependence on both silver and nitrite ion concentrations would indicate that silver is involved in the transition state as well as nitrite. Also, in this case the curved Hammett plot obtained suggests a partial positive charge on the sulphur atom in the transition state. A comparison with uncatalysed hydrolysis reactions would support a previous interpretation that thiophene‐2‐sulphonyl chlorides hydrolyze by an SN2 type mechanism which can shift toward an SN1 or an SAN process depending on the ring substituent.
Indolo[1,7‐ab][1]benzazepine, a new 18 π‐electron heterocycle
Authors: Hallberg A. , Martin A. R.
Published: March 2009

The synthesis of indolo[1,7‐ab][1]benzazepine was accomplished by cyclization of 5H‐dibenz[b,f]azepine‐5‐acetaldehyde.
The vilsmeier‐haack formylation of 1,2,3‐trimethylindole
Authors: Bastianelli Carlo , Cipiciani Antonio , Clementi Sergio , Giulietti Gianfranco
Published: March 2009

The title reaction yields mainly a side‐chain monosubstituted formyl derivative, namely 2‐(1,3‐dimethylindolyl)acetaldehyde.
Some new phenolic pyrazoles from 2′‐Hydroxychalcones
Authors: Oluwadiya J. O.
Published: March 2009

2′Hydroxychalcones react with hydrazine hydrate in water to form phenolic 4,5‐dihydro‐3,5‐diphenyl‐1H‐pyrazoles. Condensation of the pyrazoles with toluenesulphonylchloride in pyridine gave 4,5‐dihydro‐3,5‐diphenyl‐1‐toluenesulphonylpyrazoles.
5‐Imino‐Δ3‐1,2,4‐thiadiazoline derivatives with a linear N‐S…O grouping. Synthesis and crystal structures
Authors: L'abbé Gerrit , Vermeulen Guido , Toppet Suzanne , King Geoffrey S. D. , Aerts Jozef , Sengier Lieve
Published: March 2009

A series of carbonyl derivatives of 5‐imino‐Δ3‐1,2,4‐thiadiazolines has been prepared and shown by X‐ray analysis of a selected example to have a trithiapentalene‐like structure. When diphenylketene was used as acylating reagent, the primary product (14), obtained at room temperature, rearranged on heating in a polar solvent into a Δ2‐thiazolin‐4‐one (15). The structure of 15 has been confirmed by X‐ray analysis, and shown to be a zwitterion. Rearranged products (i.e., 16 and 20‐22) were also obtained when 3 was reacted with dimethyl acetylenedicarboxylate or methanesulfonyl chloride, whereas tosyl chloride gave normal tosylated derivatives (17‐19). The latter have also a nearly linear N‐S…O arrangement, but the interaction between S and O is weak.
Further studies on the reaction of N‐(2‐Hydroxyphenyl)anthranilic acids with acetic anhydride
Authors: Kim Dong Han
Published: March 2009

Reaction of N‐(2‐hydroxyphenyi)anthranilic acids (I) with acetic anhydride was investigated further. Treatment of Ia with refluxing acetic anhydride for 3 hours afforded two minor products, IIIa and IV, in addition to the previously reported IIa. Under similar conditions, the reaction of Ib with acetic anhydride afforded IIb as reported previously, and IIIb and IXb in small quantities. Treatment of IIIb with hydrazine gave X, and treatment of IXb with methoxyethylamine gave XI. When Ic was allowed to react with refluxing acetic anhydride, there were obtained three minor products, IIIc, IXc and XIII, in addition to IIc. Reaction of Id with acetic anhydride gave IId, and two minor products IXc and XIV. The formation of these minor products in the reaction of Ia‐d with acetic anhydride are discussed based on the reation mechanism proposed previously for the formation of II.
The chemistry of 5H‐benzoxazolo[3,2‐a]quinolin‐5‐ones. 5H‐Benzoxazolo[3,2‐a]quinolin‐5‐ones as synthons for the preparation of novel quinoline derivatives
Authors: Kim Dong Han
Published: March 2009

The usefulness of 5H‐benzoxazolo[3,2‐a]quinolin‐5‐ones (I) as synthons for the preparation of otherwise difficulty obtainable quinolin‐5‐ones is demonstrated. Nucleophilic reagents cleaved the oxazole ring of I at the 7‐position, resulting in 1‐(2‐hydroxyphenyl)‐2‐substituted 4‐(1H)quinolinones. Treatment of 5H‐benzoxazolo‐[3,2‐a]quinolin‐5‐one (Ia) with ethanoiic potassium hydroxide gave 1‐(2‐hydroxyphenyl)‐2‐ethoxy‐4‐(1H)quinolinone (IIIa), and attempted formylation of Ia with the Vilsmeier‐Haak reagent instead gave 2‐chloro‐1‐(2‐hydroxyphenyl)‐4‐(1H)quinolinone (II). Likewise, 10‐chloro‐5H‐benzoxazolo[3,2‐a]quinolin‐5‐ones (Ib) afforded 2‐ethoxy‐ and 2‐methoxy‐1‐(5‐chloro‐2‐hydroxyphenyl)‐4‐(1H)quinolinone (IIIb and IIId) upon treatment with ethanol and methanol, respectively. Reaction of Ib with 1‐phenylpiperazine yielded 1‐(5‐chloro‐2‐hydroxyphenyl)‐2‐(4‐phenyl‐1‐piperazinyl)‐4‐(1H)quinolinone (IV). Alkaline hydrolysis of IIIb gave 1‐(2‐hydroxy‐5‐chlorophenyl)‐2‐(1H)quinolinone (V). Treatment of IIId with epichlorohvdrin gave 1‐[5‐chloro‐2‐(2‐oxiranylmethoxy)phenyl]‐2‐methoxy‐4‐(1H)quinolinone (VIa) which in turn upon treatment with isopropylamine gave 1‐[5‐chloro‐2‐[2‐hydroxy‐3‐(1‐methylethylamino)propoxy]phenyl]‐2‐methoxy‐4‐(1H)quinolinone (VIIa). Similarly, the ethoxy analog (VIIb) was prepared. Reaction of Ib with sodium cyanide in dimethylsulfoxide produced 1‐(5‐chloro‐2‐hydroxyphenyl)‐1,4‐dihydro‐4‐oxo‐2‐quinolinecarbonitrile (X) which was hydrolized to give the corresponding carboxamide (XIV) and carboxylic acid (XI) depending on the reaction conditions. The latter yielded 2‐chloroquino[2,1‐c][1,4]benzoxazine‐6,8‐dione (XII) when heated with an excess of acetic anhydride. Treatment of XII with methoxyethylamine gave 1‐(5‐chloro‐2‐hydroyphenyl)‐1,4‐dihydro‐N‐2(methoxyethyl)‐4‐oxo‐2‐quinolinecarboxamide (XV). 1‐(5‐chloro‐2‐hydroxyphenyl)‐2‐(1H‐tetrazoyl‐5‐y1)‐4‐(1H)qutnolinone (XIII) was prepared from X. When Ib was allowed to react with sodium diethylmalonate, there was obtained [1‐(5‐chloro‐2‐hydroxyphenyl)‐1,4‐dihydro‐4‐oxo‐2‐quinolinyl]‐propanedioic acid diethyl ester (XVI) which was transformed to 1‐(5‐chloro‐2‐hydroxyphenyl)‐1,4‐dihydro‐4‐oxo‐2‐quinolinacetic acid ethyl ester (XVII) upon heating in hexamethylphosphoramide.
Dipolar additions with 1‐(4,6‐dimethylpyrimidin‐2‐yl)‐ and 1‐(4,6‐dimethoxy‐s‐triazin‐2‐yl)‐3‐oxidopyridinium betaines
Authors: Moustafa A. Heshmat , El‐Abbady Samia A. , Jones R. Alan
Published: March 2009

Cycloaddition to 1‐(4,6‐dimethylpyrimidin‐2‐yl)‐ and 1‐(4,6‐dimethoxy‐s‐triazin‐2‐yl)‐3‐oxidopyridinium betaines across the 2,6‐positions of the pyridine rings with indene, acenaphthylene and ethyl cinnamate gave substituted 8‐aza[3.2.1]bicycIooct‐3‐en‐2‐ones, whereas the [6π + 4π] cycloaddition reaction with 6,6‐dimethylfulvene gave a tricyclo[6.3.1.02.6]dodeca‐2,(6),4,9‐trien‐11‐one. Structural and configurational assignments of the cycloadducts were deduced from 1H nmr and ir spectral data.
Ring opening reaction of 3,6‐Dihydro‐2‐(1H)pyrimidinones with hydroxylamine hydrochloride
Authors: Kashima Choji , Katoh Akira , Yokota Yuko , Omote Yoshimari
Published: March 2009

1,4,6‐Trisubstituted 3,6‐dihydro‐2‐(1H)pyrimidinones (Ia‐d) easily underwent the ring opening reaction with hydroxylamine hydrochloride to afford the oximes (IIa‐d) in good yields. In the case of 3,6‐dihydro‐6‐methyl‐I‐phenyl‐2‐(1H)pyrimidinone (Ie), 2‐anilinobutyronitrile (III) was obtained in addition to the oxime (IIe). Dihydro‐2‐(1H)pyrimidinone (IV) and ‐thiones (V and VI) did not undergo the ring opening reaction.
Synthesis and structural study of quinuclidine spiro derivatives
Authors: Trigo G. G. , Martinez M. , Galvez E. , Cabezas R.
Published: March 2009

The synthesis of quinuclidine‐3‐spiro‐5′‐oxazolidine‐2′,4′‐dione, quinuclidine‐3‐spiro‐5′‐hydantoin, and some 3′‐derivatives is described. Based on the data from 1H and 13C‐nmr spectra the structure of the above mentioned compounds is established. A relationship between second order effects in 13C‐nmr spectra and H‐C‐C‐H dihedral angles is deduced.
Kinetics and Mechanism of the Isomerisation of 2,4,6‐Triphenyl‐4H‐Thiopyran
Authors: Abdallah Abdallah Abd El‐Azeem , El Nahas Hind Mostafa
Published: March 2009

Isomerisation of 2,4,6‐triphenyl‐4H‐thiopyran into 2,4,6‐triphenyl‐2H‐thiopyran has been studied kinetically and the rate of the reaction was determined in dimethylformamide. The first order rate constant could be expressed in terms of the Arrhenius parameters by the equation kt = 2.85 × 107 e−15820±110/RT.
Heteropolycyclic molecules. Part IX. Synthesis of some new benzo[b]thiophene, oxofluoreno[4,3‐b]thiophene, cyclic hydrazides and acridine compounds
Authors: Moussa H. H. , Abdel‐Meguid S.
Published: March 2009

p‐Tolyl 2‐thienyl ketone (I) condensed with dimethyl succinate in the presence of potassium t‐butoxide to give the trans (SC4H3/CO2Me) half‐ester (IIIa) whose configuration was deduced by cyclization to the corresponding benzo[b]thiophene derivatives. Carbamates, esters, cyclic hydrazides and substituted phenolic and acetic acids useful as antibacterial and antiinflamatory agents were obtained. The reaction of ketone I with malononitrile to give ylidenemalononitrile II was also considered.
Syntheses of some hydroxylated metabolites of psychotropic trifluoromethyl analogs of chlorpromazine
Authors: Nodiff E. A. , Sharma H. L. , Taunk P. C. , Shukla A. P. , Sadhnani M. D. , Tambi S. B. , Mital R. L.
Published: March 2009

The syntheses of 7‐hydroxy derivatives of trifluoperazine, nor,‐trifluoperazine, fluphenazine, triflupromazine and nor,‐triflupromazine are described. These were prepared as analytical standards for the identification of these metabolites in biological materials.
Ring transformation of condensed dihydro‐as‐triazines
Authors: Berényi E. , Benkó P. , Zólyomi G. , Tamás J.
Published: March 2009

The 2‐amino‐as‐triazino[6,5‐c]quinoline as well as 3‐aminopyrido[4,3‐e]‐as‐triazine had previously been synthetized by Berényi (1) and Benkó et al (2). In this paper, the ring transformation occuring in aqueous media of the dihydro intermediates and their salts, respectively appearing during the synthesis of 2‐substitutedamino‐as‐triazino[6,5‐c]quinolines, are reported.
Crystal and molecular structure of an active carbinolamide: 4‐hydro‐4‐dimethoxymethyl‐6‐isopropyl‐2‐oxo‐2,3‐dihydro(6H)‐1,3‐oxazine
Authors: Baker R. J. , Majeste R. J. , Trefonas L. M.
Published: March 2009

The crystal and molecular structure of the title compound has been determined by single‐crystal x‐ray diffraction techniques. The compound is of interest because of its own intrinsic anti‐tumor activity and because it is also a common moiety of a series of more active anti‐tumor agents, the maytansinoids. The compound crystallizes in the space group PĪ with 2 molecules in a unit‐cell of dimensions a = 6.912 Å,b = 7.219 Å,c = 15.272 Å, α = 119.96°, β = 104.30° and γ = 96.04°. The structure was solved by direct methods and refined to a final value of R = 0.063.
The crystal structure of 5‐amino‐6‐chloro‐4‐nitro‐2‐(β‐D‐ribofuranosyl)‐2H‐pyridazin‐3‐one
Authors: Castle Raymond N. , Thompson Robert Douglas , Dalley N. Kent , Simonsen Stanley H. , Larson Steven B.
Published: March 2009

The nucleoside, 5‐amino‐6‐chloro‐4‐nitro‐2‐β‐D‐ribofuranosyl‐2H‐pyridazin‐3‐one (4), was synthesized as part of a study to prepare potential chemotherapeutic compounds. An X‐ray crystal structure study of the compound was initiated in order to substantiate its formula and to examine its conformation and absolute configuration. The structure was determined using direct methods and refined to an R of 0.020 (Rw = 0.024). The compound has a glycosyl torsion angle of 71.2°. The structure contains three intermolecular hydrogen bonds and one intramolecular hydrogen bond.
Addition reactions of azoesters with 2‐thioquinazolinones
Authors: Giannola Libera Italo , Giammona Gaetano , Carlisi Bianca , Palazzo Salvatore
Published: March 2009

Reaction between diethyl azodicarboxylate (I) and 1,2,3,4‐tetrahydro‐2‐thioquinazolin‐4‐one (II), as a cyclic model of thiourea, both in alcoholic medium and in inert solvents has been investigated. By carrying out the reaction in an inert solvent, it was possible to isolate an intermediate. Evidence is presented that the intermediate, in turn, was converted into the final products. Structures were unequivocally assigned by mass spectrometry.
Synthesis and spectra of new 3‐carbethoxypyrazole sulfonylurea derivatives
Authors: Allah Hassan M. Faid , Mokhtar Hassan M. , Soliman R.
Published: March 2009

The reaction of 1‐benzenesulfonyl‐3‐ethoxycarbonyl‐5‐[α‐substituted‐styryl]pyrazoles (1) with isocyanate and thioisocyanate derivatives yield the corresponding benzenesulfonylurea derivatives (2and3). Bromination of1afforded the 4‐bromopyrazoles4which react with isocyanate derivatives giving5that were also obtained by bromination of2. Alkaline hydrolysis of the benzensulfonylurea derivatives2yield the corresponding pyrazole‐3‐carboxylic acids7.
Intramolecular meerwein reactions of the anthraquinone system. Synthesis, X‐ray structural analysis and spectroscopic properties of anthra[9,1‐bc:10,5‐b'c']tetrahydrodipyran derivatives
Authors: Fritz H. , Rihs G. , Sutter P. , Weis C. D.
Published: March 2009

Meerwein reactions of 1,5‐anthraquinone bis(diazonium hydrogen sulfate) with sufficiently activated olefins, such as acrylonitrile, acrylic esters, methacrylonitrile and its esters, styrene and α‐methylstyrene yielded derivatives of the new heterocyclic system anthra[9,1‐bc:10,5‐b'c']‐2,3,7,8‐tetrahydrodipyran. Isolation of derivatives was realized and yields enhanced by using dimethyl methylphosphonate as reaction medium. Compounds 5–18 were isolated as mixtures of diastereomers, some of which were separated by crystallization. Proof of structure and stereochemistry was obtained for some of the compounds by X‐ray crystallographic analysis. The 1H‐ and 13C‐nmr data provided further support. Surprisingly large chemical shift differences between some of the proton signals of isomers were observed although the two asymmetric centers are far apart through bonds and through space. The mechanism of formation is explained on the basis of redox modulation of a charge transfer complex in which the aliphatic radical attacks the oxygen atom of the anthraquinone. It is proposed to classify this new type of reaction as an intramolecular Meerwein reaction.
Antiarrhythmika. I. 2,4‐dialkylpyrimido[1,2‐a]benzimidazole
Authors: Kreutzberger Alfred , Leger Manfred
Published: March 2009

Aus der Umsetzung von 2‐Aminobenzimidazol (1) mit β‐Diketonen (2a‐d) gehen die 2,4‐Dialkylpyrimido[1,2‐a]benzimidazole (3a‐d) hervor.
Naphtho[1′,2′:5,6]pyrano[2,3–6][1,5]benzodiazepine Derivatives
Authors: Roma Giorgio , Ermili Aldo , Balbi Alessandro , Massa Elda , Di Braccio Mario
Published: March 2009

The reaction of 3‐(dimethylamino)‐1‐oxo‐1H‐naphtho[2,1‐b]pyran‐2‐carbaldehyde (Ia) with o‐phenylenediamines or N‐monosubstituted o‐phenylenediamines in refluxing glacial acetic acid afforded the corresponding naphtho[1′,2′:5,6]pyrano[2,3‐b][1,5]benzodiazepin‐15‐(8H)ones V in very good yields. A similar result was achieved when the reaction was carried out in refluxing pyridine, using N‐monosubstituted o‐phenylenediamine hydrochlorides. The isolation of a significant intermediate as well as the synthesis through a different univocal pathway confirmed the structure of the compounds V.

Moreover the reaction of Ia with N‐monosubstituted o‐phenylenediamines in refluxing pyridine generally afforded only low yields of compounds V, sometimes together with naphtho[1′,2′:5,6]pyrano[2,3‐b][1,5]benzodiazepin‐15‐(13H)ones VII, isomers of V.
Synthesis of new fulvenes containing heterocyclic substituents
Authors: Knight David B. , Hall Randall W. , Cleary Darryl G.
Published: March 2009

Four new fulvene derivatives bearing heterocyclic substituents have been prepared. Base‐promoted condensation of cyclopentadiene with tetrahydropyran‐4‐one, tetrahydrothiopyran‐4‐one, and 1‐methyl‐4‐piperidone afforded 4‐(cyclopentadienylidene)tetrahydropyran 1, 4‐(cyclopentadienylidene)tetrahydrothiopyran 2, and N‐methyl‐4‐(cyclopentadienylidene)piperidine 3 in yields ranging from 28% to 75%. Methylation of 3 with methyl iodide gave the corresponding ammonium salt, 4.
Pechmann reaction of 4‐hydroxycoumarins and thiocoumarins with cyclohexanone and ethyl cyclopentanone‐2‐carboxylates
Authors: Merchant J. R. , Koshti N. M. , Bakre K. M.
Published: March 2009

The Pechmann reaction of 4‐hydroxycoumarins with cyclohexanone and ethyl cyclopentanone‐2‐carboxylates affords 1,2,3,4‐tetrahydro[2]benzopyrano[4,3‐c][1]benzopyran‐5,12‐diones and cyclopenta[3′,4′]pyrano‐[3,2‐c][1]benzopyran‐4,11‐diones. Dehydrogenation of the former yields [2]benzopyrano[4,3‐c][1]benzopyran‐5,12‐diones. Alkaline hydrolysis of a typical compound Va affords 2‐hydroxy‐2′‐carboxydeoxybenzoin which on boiling with acetic anhydride gives an isocoumarin derivative.
Monoamine oxidase and succinate dehydrogenase inhibitory properties of substituted 1,3,4‐oxadiazole‐2‐thiones
Authors: Soni Namita , Barthwal J. P. , Saxena A. K. , Bhargava K. P. , Parmar S. S.
Published: March 2009

Fifteen new 3‐arylaminomethyl‐5‐(2‐hydroxy‐3,5‐dibromophenyl)‐1,3,4‐oxadiazole‐2‐thiones were synthesized and characterized by their sharp melting points, elemental analyses and ir spectra. These substituted oxadiazolylthiones were evaluated for their enzyme inhibitory activity. All compounds inhibited in vitro monoamine oxidase and succinate dehydrogenase activity of rat brain homogenates. The degree of monoamine oxidase inhibition ranged from 59‐93% at a final concentration of 1 × 10−4 M whereas the inhibition of succinate dehydrogenase was 49‐100% at a final concentration of 5 × 10−5 M.
Rearrangement of 3‐arylhydantoins into 3‐aminoglycocyamidines
Authors: Daboun Hamed A. , Ibrahim Yehia A.
Published: March 2009

The action of hydrazine hydrate on 5‐arylidene‐3‐aryl‐2‐methylmercaptohydantoins led to ring opening and rearrangement into 5‐arylidene‐3‐amino‐N2‐aryl‐glycocyamidines (9a‐f). The structure of the products 9a‐f was established and the mechanism of their formation was discussed.
Mass spectral fragmentation pattern of 5‐methyl‐4‐[(phenylamino)methylene]‐2,4‐dihydro‐3h‐pyrazol‐3‐one and its 2‐methyl and 2‐phenyl derivatives
Authors: Keats Neil G. , Rockley Jean E. , Summers Lindsay A.
Published: March 2009

The mass spectral fragmentation patterns of 5‐methyl‐4‐[(phenylamino)methylene]‐2,4‐dihydro‐3H‐pyrazol‐3‐one and its 2‐methyl and 2‐phenyl derivatives have been elucidated. The principal initial fragmentation route involves rupture of the exocyclic CH‐NH bond. Minor routes involve loss of H, OH and C6H5 from the molecular ion and rupture of the pyrazolone ring.
Reaction of diazoindenothiophenes with mono‐ and dibenzoylacetylenes
Authors: Mataka Shuntaro , Ohshima Takeshi , Tashiro Masashi
Published: March 2009

Reaction of diazoindenothiophenes (1 and 2) with benzoyl acetylene (4) afforded the rearrangement products (6a and b) of the initial adducts. The major product of the reaction of diazo indenothiophene (3) with 4 was butadiene derivative 8a. Reaction of 1 with dibenzoylacetylene (5a) gave the rearranged pyrazole (12), while the reaction of 2 and 3, afforded the butadiene derivatives (8b‐d).
5‐Bromobenzofuran Analog of Chloramphenicol
Authors: Bevinakatti Hanamanthsa S. , Badiger Virupax V.
Published: March 2009

dl‐threo‐2‐Dichloroacetamido‐1‐[2‐(5‐bromobenzofuranyl)] propane‐1, 3‐diol (7) was synthesised according to Sorm's method. The fragmentation of 2‐dichloroacetamido‐3‐hydroxy‐1‐[2‐(5‐bromobenzofuranyl)[‐1‐propanone (6) under electron impact is reported. The base peak is due to the rupture of the central bond whereas loss of water and McLafferty rearrangement also lead to important fragmentation pathways.
A one step synthesis of thiadiazolo[2,3‐b]quinazoline derivatives
Authors: Shawali Ahmad S. , Abdelhamid Abdou O. , Hassaneen Hamdi M. , Shetta Abdelfattah
Published: March 2009

Diazotized anthranilic acid and its methyl ester react with substituted phenacyl thiocyanates 3 to give in both cases the corresponding thiadiazolo[2,3‐b]quinazolines 7a‐e. A mechanism is proposed and it is substantiated by alternate synthesis of 7a from the hydrazidoyl chlorides 9a,b and potassium thiocyanate.
Ortho effects of a nitro group in 2′,3′ and 4′monosubstituted‐trans‐2,4‐dinitrostilbenes on electron impact. IV
Authors: Zugazagoitia R. , Martínez R. , Cortés E.
Published: March 2009

The mass spectral fragmentation patterns of thirteen 2′,3′ and 4′‐R‐trans‐2,4‐dinitrostilbenes obtained by electron impact have been studied. The main routes of fragmentation involves loss from the molecular ion due to the ortho effects of the 2‐nitro substituents. Substitution on positions 2′,3′ and 4′ of stilbene moiety does not influence the fragmentation patterns.
Studies on the synthesis of heterocyclic compounds. VII. Action of acyl halides on heterocyclic compounds containing the O‐M‐O (M  P, As, Sb) bond in the ring
Authors: Anchisi Carlo , Corda Luciana , Maccioni Antonio , Podda Gianni
Published: March 2009

The action of acyl halides on heterocyclic compounds of five‐membered rings containing an O‐M‐O (M  P, As, Sb) linkage is described. The reactions were either carried out in the presence of a solvent (benzene or toluene) or by direct heating of the reagent with the substrate. In the case of arsole, stibole and stannole derivatives, the cleavage of O‐M bond and the formation of the respective mono‐ and diesters were always obtained, while with the phospholes, no cleavage of the compounds was observed. The products IIa‐c (M = Sb) have been obtained in excellent yields starting from VIa‐c and antimony trichloride. The structure of the compounds which were prepared was determined by analytical and spectroscopic methods and also by comparations with authentic samples where possible.
Purine analogues as potential chemotherapeutic agents. III
Authors: Ram Vishnu J. , Pandey H. K. , Vlietinck Arnold J.
Published: March 2009

Alkylation of 3‐phenyl/benzyl‐8‐mercaptoxanthines and 2‐phenyl‐8‐mercaptoadenine with various alkyl halides under different conditions is studied. The structure of the compounds is confirmed by spectroscopic studies and elemental analyses.
Functionalization at C‐5 and at the C‐6 methyl group of 4‐methoxy‐6‐methyl‐2‐pyrone
Authors: Bacardit R. , Moreno‐Mañas M. , Pleixats R.
Published: March 2009

A new entry to C‐5 substituted 4‐hydroxy‐6‐methyl‐2‐pyrones has been achieved. The best conditions to prepare the monobromo and the dibromo derivatives at C‐3 and the C‐6 methyl group of the title pyrone have been defined. The synthetic applicability of the phosphonium salts at CH3‐C‐6 of both 4‐methoxy‐6‐methyl‐2‐pyrone, 5, and dehydroacetic acid, 2, has also been evaluated.
New guaianolides from Berlandiera Pumila and B. Texana, and the X‐ray crystal structure of pumilin
Authors: Korp James D. , Bernal Ivan , Fischer Nikolaus H. , Leonard Charles , Lee Ihl‐Young , LeVan Ngo
Published: March 2009

The isolation and structure determination of two new guaianolides, pumilin and its 2,3‐epoxide, from Berlandiera pumila and B. texana are reported. The structure of pumilin was determined from nmr and mass spectral data, and from an X‐ray single crystal study; the structure of the epoxide was found by comparison of nmr spectra. Pumilin is shown to be a Δ1(10)‐cis‐guaianolide with a cyclopentenone ring attached to C1 and C5, and an α‐methylene‐γ‐lactone ring trans‐fused to C6 and C7. The absolute configuration was inferred from spectral considerations and knowledge of previous structural determinations. The cd spectrum of pumilin exhibits a negative Cotton effect, and the lactone chromophore has left‐handed chirality. The cyclo‐heptene ring is in the chair configuration, with the lactone a half‐chair and the cyclopentenone essentially planar. Crystals are orthorhombic, a = 7.065, b = 13.652, c = 19.586 Å, space group P212121, Z = 4, and the final R value is 3.9%. The crystal structure is strengthened by an O···O hydrogen bond linking the molecules into infinite chains.
Synthesis of some 5H‐benzo[a]phenoxazin‐5‐one derivatives
Authors: Ueno Yoshio , Maeda Keiichi , Koshitani Jinya , Yoshida Takatoshi
Published: March 2009

The substituted 6‐bromo and 6‐chloro‐5H‐benzo[a]phenoxazin‐5‐ones, prepared by condensation of substituted 2‐aminophenols with 2,3‐dibromo or 2,3‐dichloro‐1,4‐naphthoquinone in methanolic potassium hydroxide solution, have been dehalogenated to substituted 5H‐benzo[a]phenoxazin‐5‐ones in the presence of sodium hydrosulfite dissolved in aqueous pyridine under nitrogen atmosphere.
Synthesis and properties of 7‐hydroxy‐8‐phenylxanthine and its derivatives. Disproportionation to derivatives of 8‐phenylxanthine and 6‐amino‐5‐nitrosouracil
Authors: Zvilichovsky Gury , Garbi Herzel , Nemes Eliahu
Published: March 2009

8‐Phenyl, 8‐(p‐methoxyphenyl) and 8‐(p‐chlorophenyl)‐7‐hydroxyxanthine were synthesized by ring closure of 6‐amino‐5‐nitrosouracil with benzaldehyde, p‐methoxybenzaldehyde and p‐chlorobenzaldehyde, respectively. The disproportionation of these products to the corresponding 8‐phenylxanthines and 6‐amino‐5‐nitrosouracil was studied. The dependence of the rate of the reaction on the various substituents was studied. The disproportionation reaction is inhibited by the polarophilic ethyl acetylenedicarboxylate and enhanced by phosphate.
New synthesis of 2‐nitroimidazoles
Authors: Davis Dwight P. , Kirk Kenneth L. , Cohen Louis A.
Published: March 2009

1‐Triphenylmethylimidazoles are treated with n‐butyllithium in tetrahydrofuran at 0° to form the 2‐lithio derivatives. The latter species react with n‐propyl nitrate to give l‐trityl‐2‐nitroimidazoles which, after acid hydrolysis, provide the corresponding 2‐nitroimidazoles. 2‐Nitroimidazole was obtained from imidazole in overall yields of 27–35% 4‐methyl‐2‐nitroimidazole was obtained in 40% overall yield from 4‐methyl‐imidazole. Imidazole‐4,5‐dicarboxylic acid was converted, in several steps, to l‐tritylimidazole‐4‐methanol, and the latter compound was transformed into 2‐nitroimidazole‐4‐methanol in an overall yield of 18%. Protection of the hydroxymethyl function was found to be unnecessary during carbanion formation and nitration. Attempts to nitrate 1‐methylimidazole or 1‐methoxymethylimidazole by the same procedure failed.
Reaction of ketenes with N,N‐disubstituted α‐aminomethyleneketones. XII. Synthesis of N,N‐disubstituted 4‐amino‐3‐chloro‐6‐(2‐methyl‐l‐propenyl) (2‐phenylethenyl)‐2H‐pyran‐2‐ones
Authors: Bargagna Alberto , Schenone Pietro , Bondavalli Francesco , Longobardi Mario
Published: March 2009

Cycloaddition of dichloroketene to N,N‐disubstituted (E)‐amino‐5‐methyl‐1,4‐hexadien‐3‐ones IV and (E,E)‐1‐amino‐5‐phenyl‐1,4‐pentadien‐3‐ones V occurred in moderate to good yield only in the case of aromatic N‐substitution to give N,N‐disubstituted 4‐amino‐3,3‐dichloro‐3,4‐dihydro‐6‐(2‐methyl‐l‐propenyl) (2‐phenylethenyl)‐2H‐pyran‐2‐ones, which were dehydrochlorinated with DBN to afford in good yield N,N‐disubstituted 4‐amino‐3‐chloro‐6‐(2‐methyl‐propenyl)(2‐phenylethenyl)‐2H‐pyran‐2‐ones. In the case of aliphatic N,N‐disubstitution (dimethylamino group) of enaminones IV and V, the Cycloaddition led directly in low yield to 3‐chloro‐4‐dimethylamino‐6‐(2‐methyl‐l‐propenyl)(2‐phenylethenyl)‐2H‐pyran‐2‐ones.
Convenient preparation of N‐substituted 2‐amino‐4H‐3,l‐benzoxazin‐4‐ones and 3‐substituted 2,4(1H,3H)‐quinazolinediones
Authors: Papadopoulos E. P. , Torres C. D.
Published: March 2009

Room temperature treatment of 2‐(3‐arylureido)benzoic acids (1) and methyl 2‐(3‐alkyl‐, or 3‐arylureido)‐ benzoates (2) with concentrated sulfuric acid leads to N‐substituted 2‐amino‐4H‐3,l‐benzoxazin‐4‐ones (3) in generally very good yields. The isomeric 3‐substituted 2,4(1H,3H)‐quinazolinediones (4) are conveniently made in high yield by the action of aqueous‐ethanolic sodium hydoxide on 2.
A synthesis of 5‐amino‐ and 5‐hydroxy‐l‐ethyl‐1,4‐dihydrio‐4‐oxo‐3‐quinolinecarboxylic acids and their derivatives
Authors: Tamura Yasumitsu , Fujita Masanobu , Chen Ling Ching , Ueno Kyoji , Kita Yasuyuki
Published: March 2009

The synthesis and antimicrobial activity of 5‐Hydroxy‐l‐ethyl‐1,4‐dihydrio‐4‐oxo‐3‐quinolinecarboxylic acids and their derivatives have been investigated. The 5‐hydroxy‐3‐quinolinecarboxylic acids were prepared by thermal cyclization of 3‐oxocyclohexenylaminomethylenemalonates followed by aromatiza‐tion with iodine‐ethanol, ethylation and hydrolysis of products. The 5‐amino derivatives were prepared by several steps involving novel aromatization of isoxazole intermediates.
Synthesis of as‐triazino[5,6‐b]quinoline, a new heterocyclic ring system
Authors: Hajpál István , Berényi Edit
Published: March 2009

The first representatives of a new ring system, 3‐oxo‐2,3,4,10‐tetrahydro‐as‐triazino[5,6‐b]quinoline and some of its derivatives were synthesized by cyclization of the appropriate (2‐aminobenzyl)‐triazines. These substances are in equilibrium with the tautomer 1,2,3,4‐tetrahydro form.
Etude de l'acylation de l'acétyl‐3 acétoxy‐8 indolizine par action de chlorures d'acide en présence de chlorure d'aluminium
Authors: Sliwa Henri , Blondeau Dominique
Published: March 2009

L'etude de l'acylation de l'acétyl‐3 acétoxy‐8 indolizine par action de chlorures d'acide divers en présence de chlorure d'aluminium montre que la réaction peut soit se limiter à une transestérification (cas du chlorure de benzoyle) soil se traduire par l'introduction d'un groupe acyle en ‐1 avec libération concomitante de la fonction phénol en ‐8; au cours de cette acylation en ‐1, le chlorure d'acétyle libere par clivage du groupe acétoxyle entre en compétition avec le chlorure d'acide mis en jeu. Ce dernier l'emporte dans le cas du chlorure d'éthoxalyle et des chlorures d'alcanoyle non ramifies; par contre on observe uniquement l'acétyla‐tion lorsqu'on met en oeuvre le chlorure de pivaloyle ou de phenylacetyle.

Une interprétation des resuitats mettant en jeu un processus analogue à la transposition de Fries est propose. L'hypothese d'un transfert intramoleculaire d'un groupe acyle de la fonction ester en ‐8 sur la position ‐1 est écartée au vu des résultats observés.