bluuebunny/crossref_metadata_2025 huggingface dataset:
The reaction of 1‐(N‐phenacylidene)amino‐1,2,3‐triazoles with diphenylnitrilimine
Authors: Bojilova A. , Rodios N. A. , Tsoleridis C. A. , Alexandrou N. E.
Published: March 2009

Diphenylnitrilimine reacts with 1‐(N‐phenacylidene)amino‐1,2,3‐triazoles 1 to give mainly 1,2,4‐ and 2H‐1,2,3‐triazoles 2 and 3. CNDO/2 calculations were made on the compounds 1 and the cycloaddition was also examined on the basis of the interacting frontier molecular orbitals.
Synthesis of certain 6‐alkylthio‐2,2′‐anhydro‐5‐azauridines
Authors: Purkayastha Subhasish , Panzica Raymond P.
Published: March 2009

β‐D‐Arabinofurano[1′,2′:4,5]oxazolo‐s‐triazin‐4‐one‐6‐thione (7b) and its t‐butyldimethylsilyl protected counterpart 7a were synthesized by treating the appropriate 2‐amino‐β‐D‐arabinofurano[1′,2′:4,5]‐2‐oxazoline with ethoxycarbonyl isothiocyanate. These 2,2′‐anhydro‐s‐triazine nucleosides were then subjected to alkylation under similar reaction conditions. Alkylation of 3′,5′‐bis(O‐t‐butyldimethylsilyl)‐β‐D‐arabinofurano[1′,2′:‐4,5]oxazolo‐s‐triazin‐4‐one‐6‐thione (7a) provided the targeted S‐alkylated nucleosides, i.e., the C6‐SCH3 (9a), C6‐SCH2‐CH = CH2 (10a), and C6‐S‐CH2‐C = CH (11a), in reasonable yields. Attempted deprotection of these nucleosides failed. In order to circumvent this problem, 7b was alkylated with the same reagents. In each case, instead of the expected S‐alkylated anhydronucleosides, a mixture of the 5‐N‐alkylanhydro‐s‐triazine‐4,6‐dione and 5‐N‐alkylanhydro‐s‐triazin‐4‐one‐6‐thione derivatives were obtained. The 2,2′‐anhydro linkage of 7a was also found to be more stable than the s‐triazine ring to mild base. Basic conditions displaced the C6‐sulfur substituent and eventually caused ring opening of the s‐triazine aglycone.
Synthesis of fluoromethyl, difluoromethyl and trifluoromethyl analogues of pyrazosulfuron‐ethyl as herbicides
Authors: Morimoto Katsushi , Makino Kenzi , Yamamoto Susumu , Sakata Gozyo
Published: March 2009

Ethyl 1‐fluoromethyl‐5‐(4,6‐dimethoxypyrimidin‐2‐ylcarbamoylsulfamoyl)pyrazole‐4‐carboxylate 1b, a new fluoromethyl analogue of the herbicide pyrazosulfuron‐ethyl la, was prepared from ethyl 1‐fluoromethylpyrazole‐4‐carboxylate 4b. The difluoromethyl and trifluoromethyl analogues 1c,d were also synthesized from ethyl pyrazole‐4‐carboxylate 2 via difluorocarbene reaction.
A facile synthesis of novel 1,2‐diazepino[3,4‐b]quinoxalines by a 1,3‐dipolar cycloaddition reaction
Authors: Kim Ho Sik , Kurasawa Yoshihisa , Yoshii Chiemi , Masuyama Minako , Takada Atsushi , Okamoto Yoshihisa
Published: March 2009

The 1,3‐dipolar cycloaddition reaction of the quinoxaline 4‐oxides 4a,b with 2‐chloroacrylonitrile gave the 2,3‐dihydro‐1H‐1,2‐diazepino[3,4‐b]quinoxalines 5a,b, respectively, which were converted into the 2,3,4,6‐tetrahydro‐1H‐1,2‐diazepino[3,4‐b]quinoxalines 7a,b and 8a,b, respectively.
The synthesis of 6‐C‐substituted 9‐methoxymethylpurine derivatives
Authors: Hamamichi Norimitsu , Miyasaka Tadashi
Published: March 2009

6‐Cyanomethylene (2), which was prepared via 1 by substitution with malononitrile, has been catalytically hydrogenated to the α‐(aminomethylene)‐9‐(methoxymethyl)‐9H‐purine‐6‐acetonitrile (3) in good yield using N,N‐dimethylformamide‐benzene as solvent over Pd‐C under medium pressure. Intermediate 3 was derived to aldehyde 5 by hydrolysis with acid or base. Substitution of 3 with amines gave the corresponding alkylamines 6 and 7. Reaction of 3 with hydrazine and acetamidine hydrochloride gave pyrazole derivative 8 and pyrimidine derivative 9, respectively.
Reaction of 3‐methylindole and 2,3‐dimethylindole with dimethyl acetylenedicarboxylate using boron trifluoride‐diethyl ether catalysis
Authors: Rodrigues J.Augusto R. , Verardo L. I.
Published: March 2009

Reactions of dimethyl acetylenedicarboxylate with 3‐methylindole and 2,3‐dimethylindole under boron trifluoride‐diethyl ether catalysis were carried out at low temperature (0–25°). Thermally unstable cyclobutenes were isolated, mainly in apolar solvents, which isomerized to benzazepines. The other compounds isolated were Michael adducts and dihydro‐2‐oxocarbazoles.
7,10A‐Methanocycloocta[c,d]indazoles: Diisophoranes incorporating the pyrazole ring system
Authors: Kurzer Frederick , Langer Stanley S.
Published: March 2009

Compounds of the novel 7,10a‐methanocycloocta[c,d]indazole ring‐system 5, 7 are obtained by the action of hydrazines on 1‐chloro(or hydroxy)diisophor‐2,7‐en‐3‐ones 1–3. Their formulation agrees with their origin and their chemical and spectral characteristics. Analogous syntheses of two comparable ring‐systems include the production of a substituted 7,10a‐methanocycloocta[g,h][2,1]benzisoxazole 10 by a facile cyclodehydration of the oxime of diisophorone 9a, and that of the indole‐analogue 13 by the action of aniline on diisophorone‐1‐carboxylic acid 11.
Synthesis of 4‐aminocycloheptimidazoles
Authors: Ishida Noritoshi , Imafuku Kimiaki
Published: March 2009

2‐Methyl‐ 1a, 2‐phenyl‐ 1b, and 2‐amino‐4‐(2‐methyl‐1,3‐dioxolan‐2‐yl)cycloheptimidazole (1c) were treated with hydrazoic acid to give the corresponding 4‐aminocycloheptimidazoles, respectively. However, the reaction of 4‐(2‐methyl‐1,3‐dioxolan‐2‐yl)cycloheptimidazole gave complex material. Some approaches to the synthesis of 4‐aminonocycloheptimidazole itself are also described.
Synthesis of fluorantheno[1,2‐b]thiophene and fluorantheno[3,2‐b]thiophene, isosteres of benzofluoranthenes
Authors: Lee‐Ruff E. , Chung Y. S.
Published: March 2009

The total syntheses of fluorantheno[1,2‐b]thiophene and fluorantheno[3,2‐b]thiophene are reported. The common cyclobutanone intermediate which was obtained by [2 + 2] addition of fluorenylidene ketene with 2,3‐dihydrothiophene underwent regioselectively α or β ring opening to lead to linear or angular PAC skeleton molecules under desired conditions. 2,3‐Dichloro‐5,6‐dicyanobenzoquinone was applied for aromatization to achieve the formation of PAC's. These two isosteres exhibit very similar uv/visible spectra to benzo[a] and [b]fluoranthenes respectively. Spectroscopic data used for their structural assignments is also discussed.
New tetracyclic compounds containing the β‐carboline moiety
Authors: Giudice Maria Rosaria Del , Gatta Franco , Settimj Guido
Published: March 2009

Oxidation of 1‐methyl‐3‐methoxycarbonyl‐β‐carboline with selenium dioxide gave 1‐formyl‐3‐methoxycarbonyl‐β‐carboline II. Compound II reacted with acetic or propionic anhydride to give easily the 2‐methoxycarbonyl‐6H‐indolo[3,2,1‐d,e][1,5]naphthyridin‐6‐ones III; reaction of II with some primary amines led to the formation of the Schiff bases IV, which were reduced to the 1‐aminomethyl‐3‐methoxycarbonyl‐β‐carbolines V with sodium borohydride.

Cyclization of V with aqueous formaldehyde led to the pyrimido[3,4,5‐lm]pyrido[3,4‐b]indoles VI.

Analogously, cyclization with formaldehyde, acetone or 1,1′‐carbonyldiimidazole of the 3‐aminomethyl‐ 1,2,3,4‐tetrahydro‐β‐carbolines VIII, obtained by reaction of 3‐methoxycarbonyl‐1,2,3,4‐tetrahydro‐β‐carboline VII with amines followed by lithium aluminium hydride reduction of the resulting amides, gave the imidazo[1′,5′‐1,6]pyrido[3,4‐b]indoles IX and X.

Dieckmann cyclization of 3‐methoxycarbonyl‐2‐[(3‐ethoxycarbonyl)‐1‐propyl]‐1,2,3,4‐tetrahydro‐β‐carboline XI led to a 1:1 mixture of the β‐ketoesters XII and XIII, which underwent deethoxycarbonylation to 5,6,8,9,10,11,11a,12‐octahydroindolo[3,2‐b]quinolizin‐11‐one XIV.

Finally, the polyphosphoric acid (or esters) catalyzed cyclization of the N‐acyl derivatives XVI of 3‐hydrazinocarbonyl‐β‐carboline XV led smoothly to the 3‐(1,3,4‐oxadiazol‐2‐yl)‐β‐carbolines XVII.
Synthesis of some fused triazoloquinolines
Authors: Ramalingam T. , Murty M. S. R. , Nageswar Y. V. D. , Sattur P. B.
Published: March 2009

The reaction of 3‐amino‐1,2,4‐triazolo[4,3‐a]quinoline (II) with diethyl ethoxymethylenemalonate and ethyl acetoacetate/ethyl trifluoroacetoacetate afforded 10‐carboethoxy‐9‐oxo‐9H‐pyrimido[1′,2′:1,5][1,2,4]triazolo‐[4,3‐a]quinoline (III) and 11‐methyl/trifluoromethyl‐9‐oxo‐9H‐pyrimido[1′,2′:1,5][1,2,4]triazolo[4,3‐a]quinoline (IV/V) respectively. 2‐Chloropyridine‐3‐carboxylic acid chloride reacted with II to yield 5‐oxo‐5H‐pyrido‐[3″,2″:5′,6′]pyrimido[1′,2′:1,5][1,2,4]triazolo[4,3‐a]quinoline (VII), a new ring system.
Acidity constants of benzimidazolium ketone and pyridinium aldehyde hydrates
Authors: Owen Terence C.
Published: March 2009

Acidity constants (pKa) of the hydroxyl groups of the quaternary heterocyclonium carbinols 2‐hydroxy‐methyl‐1‐methylpyridinium and 2‐(1‐hydroxyethyl)‐1,3‐dimethylbenzimidazolium ions are 11.5 ± 0.5. Acidity constants of the corresponding gem diols, the hydrates of 2‐formyl‐1‐methyl‐pyridinium and 2‐acetyl‐1,3‐dimethylbenzimidazolium ions hence are estimated to be 9 ± 0.5. Accordingly, acidity constants of the hydroxyl groups of pyridine aldehyde salt hydrates are 12–13, not 4–5 as previously reported; and conversely, acidity constants of the pyridinium groups are 4–5, not 12–13.
The synthesis of benzofuroquinolines. VIII. Some halobenzofuro[2,3‐c]quinoline derivatives
Authors: Yamaguchi Seiji , Yokoi Takashi , Yamada Minoru , Arai Hitomi , Uchiuzo Yasuto , Kawase Yoshiyuki
Published: March 2009

Three 2‐halo‐6(5H)‐benzofuro[2,3‐c]quinolinones 1 (X = F, Cl, Br) were synthesized in two procedures, photocyclization of N‐benzyl‐N‐(p‐halophenyl)‐2‐benzofurancarboxamides 3 (X = F, Cl, Br) and condensation of 2‐amino‐2′‐hydroxybenzophenones 7 (X = F, Cl, Br) with chloroacetonitrile. Three 2‐halo‐6‐methylbenzofuro[2,3‐c]quinolines 2 (X = F, Cl, Br) were also synthesized by the condensation of 2‐amino‐5‐halo‐2′‐hydroxybenzophenones 7 (X = F, Cl, Br) with chloroacetone.
Synthesis and chemical reactivity of c‐5 substituted 6,7‐bis‐(hydroxymethyl)‐1H‐pyrrolizine biscarbamate tumor inhibitors
Authors: Anderson Wayne K. , Mach Robert H.
Published: March 2009

A series of C‐5 substituted pyrrolizine biscarbamate alkylating agents were synthesized and evaluated in an in vitro alkylation assay. Introduction of electron‐withdrawing substituents at the C‐5 position resulted in a dramatic decrease in chemical reactivity toward the model nucleophile 4‐(4‐nitrobenzyl)pyridine (NBP).
NMR Determination of absolute configurations in 2‐alkylthiazolidine‐4‐carboxylic acids
Authors: Restelli Angelo , Annunziata Rita , Pellacini F. , Ferrario F.
Published: March 2009

The condensation of L‐cysteine with enantiomerically pure aldehyde 2a and 2b afforded a mixture of 2‐substituted thiazolidine diastereomers 1a‐b and 1c‐d, respectively. The present paper deals with the use of nuclear Overhauser effect (nOe) in determining the absolute configurations of the stereocenters.
1,3‐Dipolar cycloadditions of alkyl azides with picryl isothiocyanate:Isolation of stable monoadducts
Authors: L'Abbá Gerrit , Brems Patrick , Albrecht Ernestine
Published: March 2009

Picryl isothiocyanate (4), prepared in a two‐step sequence from picryl chloride (2), reacts smoothly with alkyl azides to yield 4‐alkyl‐5‐picrylimino‐1,2,3,4‐thiatriazolines 5 which are stable below 100°. These adducts combine with isocyanates in a bimolecular process with loss of nitrogen, similar to the formation of phenylimino derivatives but different from that of sulfonyliminothiatriazolines.
Porphyrins meso‐substituted with phenanthrene and 1,10‐phenanthroline
Authors: Kus Piotr , Knerr Gary , Czuchajowski Leszek
Published: March 2009

Meso‐tetrakis(9‐phenanthryl)porphyrin and meso‐tetrakis(1,10‐phenanthrolin‐4‐yl)porphyrin were obtained and characterized by spectroscopy methods. The porphyrin containing phenanthroline substituents was formed with much smaller yield. It showed much slower progress of metallation with Cu(I) and Zn(II) ions than the phenanthreneporphyrin. While attachment of phenanthrene did not result in any meaningful changes in the uv vis spectrum when compared to other meso‐substituted tetraarylporphyrins (except that of [2.2]paracyclophanylporphyrin), the appearance of two N centers in each meso substituent substantially altered porphyrin absorption in the 530–600 nm region. Although the 1 H nmr 300 MHz spectra of both porphyrins showed the same deshielding of β‐pyrrole protons, the shielding of NH protons was more advanced in phenanthrolineporphyrin.
Synthesis of 7‐amino‐1,4‐dihydro‐4‐oxo‐6‐(trifluoromethyl)‐1,8‐naphthyridines. The use of methylidenemalonate as an activating group and a sulfur assisted cyclization
Authors: Bridges A. J. , Sanchez J. P.
Published: March 2009

2,6‐Dichloro‐3‐(trifluoromethyl)pyridine3was used to develop a six‐step preparation of 7‐amino‐4‐oxo‐6‐(trifluoromethyl)naphthyridines. The CF3group deactivated the pyridine ring towards both nucleophiles and electrophiles. A new reagent for pyridone annulation, the aminomethylidenemalonate anion, is described, along with several strategies to manipulate the electron density of substituted pyridines.
Synthesis of nitrogen‐containing heterocycles. 5. A new route to 5‐amino‐[1,2,4]triazolo[1,5‐a][1,3,5]triazine derivatives
Authors: Miyamoto Yoshiko , Yamazaki Chiji , Matzui Megumi
Published: March 2009

Treatment of certain diaminomethylenehydrazones 1 of aromatic carbonyl compounds with ethyl N‐cyanoimidate (2) in acetonitrile in the presence of a tertiary amine at room temperature gives the corresponding amino(N‐cyanoiminomethyl)aminomethylenehydrazones 3 in high yields. The intermediate 3 can readily be cyclized to the corresponding 5‐amino‐2,3‐dihydro[1,2,4]triazolo[1,5‐a][1,3,5]triazines 4 in moderate to good yields by brief heating in acetonitrile. When the reaction of diaminomethylenehydrazones 1 with ethyl N‐cyanoimidate (2) is performed at reflux temperature in the presence of a tertiary amine, 5‐amino‐2,3‐dihydro[1,2,4]triazolo[1,5‐a]1,3,5]triazines 4 can be directly obtained in moderate yields. The yields of triazolotriazine produced by the one‐step synthesis are generally comparable or even higher than the overall yields from the two‐step procedure.
Reaction of pyridinium disubstituted methylides with diphenylcyclopropenethione
Authors: Ikemi Yukio
Published: March 2009

Diphenylcyclopropenethione undergoes nucleophilic attack by pyridinium disubstituted ylides 1a‐1e to produce the corresponding 2‐pyranthione 3a, 2‐pyrone 4a or 4c, thiopyran‐2‐one 6a, 6b, 6d or 6e, and/or 5H‐thieno[3,2‐b]thiopyran 5a.
Synthesis of derivatives of pyrazino[1,2‐a]pyrimidin‐4‐ones
Authors: Dennin F. , Blondeau D. , Sliwa H.
Published: March 2009

3‐Alkoxy‐2‐aminopyrazines have been condensed with ethyl ethoxymethylenemalonate and isopropylidene methoxymethylenemalonate to afford 9‐alkoxypyrazino[1,2‐a]pyrimidin‐4‐ones substituted in the first case by an ethoxycarbonyl group at 3 position.
Pyridazines. LII. Novel 1,2‐diazine analogues of 2‐aminobenzophenone via directed lithiation
Authors: Haider Norbert , Heinisch Gottfried , Kemetmüller Gudrun
Published: March 2009

The preparation of novel pyridazine analogues of 2‐aminobenzophenone, namely 2‐(substituted)aminophenyl 3‐pyridazinyl ketones 2, 3, 4a,b, achieved by reaction of methyl 3‐pyridazinecarboxylate with ortho‐lithiated aniline derivatives, is reported.
Arene imine derivatives of chrysene and of benzo[g]chrysene: 1a,11c‐dihydrochryseno[5,6‐b]azirine and 1a,13c‐dihydrobenzo[11,12]chryseno[5,6‐b]azirine
Authors: Abu‐Shqara Elias , Elg'Amal Shafea , Blum Jochanan
Published: March 2009

The syntheses of the K‐iraines (which are also benzo‐bay‐region derivatives) of chrysene (1) and benzo[g]‐chrysene (2) are described. The preparation of 1a,11c‐dihydrochryseno[5,6‐b]azirine (5) was accomplished by treatment of 1a,11c‐dihydrochryseno[5,6‐b]oxirene (4) with sodium azide, and the mixture oftrans‐azido‐alcohols6and7, so formed, was either cyclized with triethyl phosphite, or converted intoE‐6‐azido‐5‐chloro‐5,6‐dihydrochrysene (8) followed by lithium aluminium hydride reduction. The synthesis of 1a,13c‐dihydrobenzo‐[11,12]chryseno[5,6‐b]azirine (12) included the transformation of the corresponding oxide11into a mixture ofE‐9‐azido‐9,10‐dihydrobenzo[g]chrysen‐10‐ol (13) andE‐10‐azido‐9,10‐dihydrobenzo[g]chrysen‐9‐ol (14), and reaction with tri‐n‐butylphosphine to give a mixture of Staudinger adducts15and16that underwent thermal decomposition into12upon heating in boiling dichloromethane.
The effect of pH on the course of the photoreaction of 2,4‐pyridinedicarbonitrile with benzophenone in aqueous 2 propanol: Reduction vs substitution
Authors: Caronna Tullio , Morrocchi Sergio , Vittimberga Bruno M.
Published: March 2009

The photoinitiated reactions of 2,4‐pyridinedicarbonitrile (1) and benzophenone in neutral, acidic, and basic 3:1 2‐propanol‐water and the kinetics of disappearance of 1, have been studied. Pyridinyl radical anion forms as an intermediate by an electron transfer. In acidic solution substitution of the cyano group in the 2 position and in the 2 and 4 positions with diphenylmethanol occurs. In neutral medium both substitution at the 2‐position and reduction, in which the cyano group at the 4 position is replaced by hydrogen, are observed. In basic solution in which protonation of the radical anion is not likely, only reduction occurs. The rates of formation and relative yields of these products depends on the pH of the solution. A mechanism is discussed.
Preparation, X‐ray crystal structure and 13C‐ and 1H‐NMR study of 1‐methyl‐2‐(N‐methyl‐N‐phenylglycyl)‐3‐(N‐methylanilino)indole
Authors: Farfán Norberto , Hernández J. Manuel , Joseph‐Nathan Pedro , Contreras Rosalinda
Published: March 2009

Reaction of N‐methylaniline with 40% glyoxal yields 1‐methyl‐2‐(N‐methyl‐N‐phenylglycyl)‐3‐(N‐methylanilino)indole (1a) as the main product together with 1‐methyl‐3‐(N‐methylanilino)indole (1b). The reaction appears to be general for aromatic secondary amines since N‐ethylaniline and N‐phenylbenzylamine yield the corresponding indoles. The structure of 1a has been verified by single crystal X‐ray diffraction. Compound 1a (C25H25N3O) crystallized in the triclinic space group Pl̄ with cell dimensions a = 10.085(3)Å, b = 10.371(3)Å, c = 11.908(5)Å, α = 74.2(3)°, β = 74.7(3)° and γ = 60.7(2)° with Z = 2. The complete 1H and 13C nmr assignment of indoles 1a and 1b was achieved from two‐dimensional HETCOR and COSY spectra with the aid of homonuclear and heteronuclear double resonance experiments.
N‐chlorination of dilantin and sorbinil
Authors: Lipinski Christopher A. , Bordner Jon , Butterfield Garth C. , Marinovic Lilian C.
Published: March 2009

The synthesis, stability, X‐ray structural characterization and 13C nmr shifts of N‐1′, N‐3′‐dichloro and N‐1′‐monochlorohydantoin derivatives of the anticonvulsant dilantin and the aldose reductase inhibitor sorbinil are described. These chlorinated derivatives may be involved in drug induced hypersensitivity reactions.
Heterocyclic system. XI. Synthesis of 1H,4H‐pyrazolo[4,3‐b]pyrrolizine and 2H,4H‐pyrazolo[4,3‐b]pyrrolizine derivatives
Authors: Massa Silvio , Mai Antonello , Artico Marino , Corelli Federico
Published: March 2009

Cyclization of pyrrolidinocarboxamide derivatives of 1‐phenyl‐5‐(1H‐pyrrol‐1‐yl)‐1H‐pyrazole‐4‐carboxylic acid and 2‐phenyl‐3‐(1H‐pyrrol‐1‐yl)‐1H‐pyrazole‐4‐carboxylic acid afforded imminium salts which were transformed into the corresponding ketones. Further reduction of the latter compounds furnished the title derivatives.
Synthesis of 5‐substituted pyrimidines.ortho‐directed lithiation of pyrimidine derivatives
Authors: Wada Akimori , Yamamoto Junpei , Hamaoka Yuka , Ohki Kazuhiro , Nagai Sotoo , Kanatomo Shōichi
Published: March 2009

ortho‐Directed lithiation of some pyrimidines has been investigated. Treatment of 2‐ and/or 4‐alkoxy or acylaminopyrimidine with lithium 2,2,6,6‐tetramethylpiperidide in ether at 0°, followed by quenching with various electrophiles afforded the corresponding 5‐substituted pyrimidines.
Ring transformation of 5‐acylpyrimidines into 4‐acylpyrazoles with hydrazine and phenylhydrazine in acidic medium
Authors: Takagi Kaname , Bajnati Abdelilah , Hubert‐Habart Michel , Terada Hiroshi
Published: March 2009

5‐Benzoyl‐4‐methylpyrimidines 4a,b and 5‐acetyl‐4‐phenylpyrimidines 5a,b reacted with hydrazines in alcoholic acidic medium to give respectively 4‐acetyl‐3‐phenylpyrazoles 7, 9 and 10 and 4‐benzoyl‐3‐methylpyrazoles 6, 8 and 11. In the reaction with phenylhydrazine, 5‐benzoyl‐4‐methyl‐2‐methylthiopyrimidine (4a) led exclusively to 4‐acetyl‐1,3‐diphenylpyrazole (10) as 5‐acetyl4‐phenyl‐2‐methylthiopyrimidine (5a) led to 4‐benzoyl‐3‐methyl‐1‐phenylpyrazole (11) via the initial formation of phenylhydrazones of pyrimidines 4a and 5a. However, 5‐benzoyl‐4‐methyl‐2‐phenylpyrimidine (4b) and 5‐acetyl‐2,4‐diphenylpyrimidine (5b) reacted with phenylhydrazine to afford, each of them, a mixture of two isomeric pyrazoles. The mechanism of these ring contraction reactions is discussed.
1,2,4‐benzothiadiazine 1,1‐dioxides 3. Reactions of 2‐aminobenzenesulfonamide with chloroalkyl isocyanates
Authors: Chern Ji‐Wang , Ho Ching‐Po , Wu Ying‐Hwa , Rong Jiann‐Gwo , Liu Kang‐Chien , Cheng Ming‐Chu , Wang Yu
Published: March 2009

Reactions of 2‐aminobenzenesulfonamide (1) with allyl, methyl, 2‐chloroethyl aor 3‐chloropropyl isocyanates gave 2‐(methylureido)‐, 2‐(allylureido)‐, 2‐(2′‐chloroethylureido)‐ and 2‐(3′‐chloropropylureido)‐benzene sulfonamides 3a,b and 7a,b in excellent yields. Treatment of 3a,b at refluxing temperature of DMF afforded 2H‐1,2,4‐benzothiadiazin‐3(4H)‐one 1,1‐dioxide (4) in good yield. However, when compounds 7a,b were refluxed in 2‐propanol, 3‐(2′‐aminoethoxy)‐2H‐1,2,4‐benzothiadiazine 1,1‐dioxide (11a) and 3‐(3′‐aminopropoxy)‐2H‐1,2,4‐benzothiadiazine 1,1‐dioxide (11b) were obtained in a form of the hydrochloride salts 10a,b in 87% and 78% yields respectively. Heating 11b in ethanol gave a dimeric form of 2H‐1,2,4‐benzothiadiazin‐3(4H)‐one 1,1‐dioxide and 3‐(3′‐aminopropoxy)‐2H‐1,2,4‐benzothiadiazine 1,1‐dioxide (12) in 55% yield. Treating of 7a,b or 11a,b with triethylamine at the refluxing temperature of 2‐propanol afforded 3‐(2′‐hydroxyethylamino)‐2H‐1,2,4‐benzothiadiazine 1,1‐dioxide (2a) and 3‐(3′‐hydroxypropylamine)‐2H‐1,2,4‐benzothiadiazine 1,1‐dioxide (2b) via a Smiles rearrangement.
Synthèse, réduction chimique et électrochimique de benzopyranno[1][4,3‐e] et [3,4‐e]pyrimido[1,2‐b]‐as‐triazinones
Authors: Vinot Nicole , Bellec Christian , Maitte Pierre
Published: March 2009

Les amino‐2 et ‐3 9H‐benzopyranno[1][4,3‐e] et [3,4‐e]‐as‐triazines réagissent avec les β‐cétoesters ce qui donne des benzopyranno[1][4,3‐e] et [3,4‐e]pyrimido[1,2‐6]‐as‐triazinones‐1 ou 4. Ces nouveaux hétérocycles sont réduits en dihydro ou tétrahydrotriazinones, selon l'agent réducteur.
Synthesis and reactivity of 1,2,4‐oxathiazolidin‐3‐imines
Authors: L'abbé Gerrit , Buelens Karin
Published: March 2009

Thiatriazoline 4a decomposes in acetone and yields a thermolabile crystalline material, identified as the 1,2,4‐oxathiazole derivative 6a on the basis of ir, 1H and 13C nmr spectroscopy. It degrades to 7a in the crystalline state as well as in solution. Cycloaddition‐elimination reactions of 6a with isothiocyanates proceed rapidly and furnish the same products as previously obtained from 4a. Some other reactions of 4 with carbonyl compounds were briefly investigated and provide evidence for the formation of unstable 1,2,4‐oxathiazolidines.
Formation of acetamido‐Aza‐steroids
Authors: Nikolaropoulos Sotirios , Catsoulacos Panayotis
Published: March 2009

Beckmann rearrangement of 3α‐ and 3β‐acetamido‐5α‐androstan‐17‐one oximes gives homo‐aza compounds and the corresponding “second order” Beckmann cleavage ω‐cyanoolefin. The mixture of the compounds produced, was separated by column chromatography. The structure of the lactams and the exocyclic nitriles was apparent from ir and nmr spectra.
Phenylurethans of pyrazolidinols and piperidazinols as anticonvulsants
Authors: Kornet Milton J.
Published: March 2009

The synthesis of 1,2‐diethyl‐4‐hydroxymethylpyrazolidine (II) was accomplished in two steps from 1,2‐diethyl‐4‐ethoxycarbonylpyrazolidine (I). Also, 1,2‐dimethyl‐4‐hydroxypiperidazine (VI) was prepared in three steps from 1,2‐diethoxycarbonyl‐1,2,3,6‐tetrahydropyridazine (IV). The two alcohols were added to several aryl isocyanates and afforded fourteen new phenylurethan derivatives which showed moderate anticonvulsant activity in mice.
8‐Hydroxylated derivatives of diazabicyclo[4.3.0]nonanes, 2,5‐dioxodiazabicyclo[4.3.0]nonanes and some related esters
Authors: Diafi Lahcen , Couquelet Jacques , Tronche Pierre , Gardette Daniel , Gramain Jean‐Claude
Published: March 2009

Pharmacological considerations prompted the authors to synthesize a series of 8‐hydroxylated optically active derivatives of diazabicyclo[4.3.0]nonanes and of their 2,5‐dioxo analogs from trans‐4‐hydroxy‐L‐proline. Esterification with appropriate anhydrides led to the corresponding esters with 6S,8R configuration. Inversion of configuration at C‐8 was performed using Mitsunobu method and led to the diastereoisomeric series of 6S,8S esters. A tentative pharmacological evaluation was carried out in the area of sedative and spasmolytic activities.
Diporphyrinyl derivatives of 1,10‐phenanthroline and 2,2′‐bipyridyl
Authors: Kus Piotr , Knerr Gary , Czuchajowski Leszek
Published: March 2009

The title derivatives were synthesized containing two meso‐tri‐p‐tolylpheneleneporphyrin units attached via amide bridges to 4,7‐ and 4,4′ positions of the respective heteroaromatic spacers.
Cyclisations intramoléculaires: Accés aux 9‐oxo‐4H,9H‐pyrrolo[1,2‐a]thieno[2,3‐d]pyridine et 4‐oxo‐4H,9H‐pyrrolo[1,2‐a]thieno[2,3‐d]pyridine. Synthèse des pyrrolo[1,2‐a]thieno[3,2‐e][1,4]diazepine et pyrrolo[1,2‐a]thieno[2,3‐e][1,4]diazepine
Authors: Decroix Bernard , Morel Jean
Published: March 2009

La synthèse de 1‐(2‐ ou 3‐thienylmethyl)pyrrole ainsi que certains dérivés est effectuée à partir d'halogenomethylthiophenes. La cyclisation intramoléculaire des acides 19 et 20 fournit les pyrrolothienopyridines 22 et 23. D'autre part les azotures 29 et 30 en milieu acide conduisent aux pyrrolo[1,2‐a]thieno[3,2‐e][1,4]diazepine et pyrrolo[1,2‐a]thieno[2,3‐e][1,4]diazepine.
Acetylenchemie. 18. Mitt.: Molekülvariationen am rutaceenalkaloid dictamnin via Pd/Cu katalysierte alkin‐kupplung
Authors: Reisch Johannes , Nordhaus Petra
Published: March 2009

Bei der phasentransfer‐katalysierten Umsetzung von 3‐Jod‐4‐methoxy‐2(1H)chinolinon (1) mit 1‐Alkinen 2 entsteht das Kupplungsprodukt 3 und/oder das 2‐substituierte Furo[2,3‐b]chinolin (4).
The synthesis of two novel fused thienopyridopyridazines
Authors: Luo Jiann‐Kuan , Castle Raymond N.
Published: March 2009

Two previously unknown thienopyridopyridazine ring systems, thieno[2′,3′:5,6]pyrido[2,3‐d]pyridazine‐5,8,9(4H,6H,7H)‐trione (4) and thieno[3′,2′:5,6]pyrido[2,3‐d]pyridazine‐4,5,8(6H,7H,9H)‐trione (10) were synthesized and their chlorination reactions with phosphorus oxychloride were investigated.
Synthesis of 2,5‐diethyl‐3,4‐bis(trifluoromethyl)furan and its derivatives
Authors: Nishida Masakazu , Hayakawa Yoshio , Matsui Masaki , Shibata Katsuyoshi , Muramatsu Hiroshige
Published: March 2009

The addition reaction of propionaldehyde to hexafluoro‐2‐butyne (1) under γ‐ray irradiation gave trans‐6,6,6‐trifluoro‐4‐trifluoromethyl‐4‐hexen‐3‐one (2) and 4,5‐bis(trifluoromethyl)octa‐3,6‐dione (3). The latter compound was treated with sulfuric acid to give 2,5‐diethyl‐3,4‐bis(trifluoromethyl)furan (4a). Several reactions, such as bromination, dehydrobromination and oxidation, were carried out to prepare derivatives of 4a.
Synthesis and hydrolysis of substituted tetrahydropyrimidinium salts. Behaviour of the degradation products on varying pH
Authors: Reverdito Ana M. , Orelli Liliana , Dalmaso Mónica , Perillo Isabel , Fernández Beatriz M.
Published: March 2009

Reaction of 1,2‐diaryl‐3‐methyl‐1,4,5,6‐tetrahydropyrimidinium iodides 1a‐i with alkaline solutions afforded N‐aroyl‐N‐aryl‐N'‐methyltrimethylenediamines 2a‐i. Compounds 2 are stable under acid conditions but in neutral or alkaline media spontaneously rearrange giving N‐aroyl‐N'‐aryl‐N‐methyltrimethylenediamines 3a‐i. Treating compounds 3 with concentrated acids reverse reaction takes place.

Kinetic studies were performed on this intramolecular N → N' aroyl transfer over the Ho‐pH range ‐0.9 to 2.30. Compounds 3 undergo acyl transfer to give 2 by a mechanism which involves a change in the rate determining step from formation to acid‐catalysed decomposition of a six‐membered heterocyclic intermediate on going from Ho to pH values. The existence of maxima in the pH rate profile allow to determine apparent pKa values of the hexahydropyrimidine intermediates which gave good correlation with the Swain F substituent constants. Stability of these heterocycles was also predicted by determination of thermodinamic parameters. Comparisons are made with the behaviour of five‐membered heterocyclic intermediates (imidazolidine derivatives) which were studied in an earlier paper.
An improved synthesis of anticancer benzothiopyranoindazoles. An efficient large‐scale β‐aminoethylation procedure
Authors: Beylin Vladimir G. , Colbry Norman L. , Giordani Anne B. , Goel Om P. , Johnson Donald R. , Leeds Robert L. , Leja Boguslawa , Lewis Edward P. , Lustgarten David M. , Showalter H. D. Hollis , Sercel Anthony D. , Reily Michael D. , Uhlendorf Susan E. , Zisek Katherine A. , Mcdonnell Peter
Published: March 2009

Improved processes for the synthesis of bulk quantities of the benzothiopyranoindazole clinical agent CI‐958 and A‐ring congeners is reported. The process chosen for scale‐up operations achieves β‐aminoethylation of an anilino precursor via a three‐step sequence (acylation, reduction, deprotection) starting from N‐(trityl)glycine. Detailed analytical data are reported for the target compounds and most intermediates, and detailed spectroscopy is given for CI‐958.
A new approach to the synthesis of substituted 2(1H)‐quinolinones
Authors: Theodoridis George , Malamas Patricia
Published: March 2009

A new synthetic approach for the preparation of substituted 2(1H)‐quinolinones 5 from readily available anilines has been developed. The four step procedure resulted in the synthesis of a variety of substituted 2(1H)‐quinolinones in good yields and under mild reaction conditions.
Synthesis of analogs of amrinone: 4‐(3,4‐Disubstitutedphenyl)pyridines and derivatives thereof
Authors: Singh Baldev , Lesher George Y.
Published: March 2009

4‐(3,4‐Dimethoxyphenyl)pyridine (5c) prepared by the coupling of 3,4‐dimethoxyphenyldiazonium chloride with pyridine was converted to 4‐(4‐pyridinyl)benzene‐1,2‐diol (6c) by treating with hydrobromic acid. Diazotization of 4‐(4‐pyridinyl)benzeneamine (7) and 3‐(4‐pyridinyl)benzeneamine (12) gave the corresponding phenols 8 and 13 which were nitrated to give 2‐nitro‐4‐(4‐pyridinyl)phenol (9) and 2‐nitro‐5‐(4‐pyridinyl)‐phenol (14), respectively. Reduction of these nitrophenols gave the corresponding aminophenols 10 and 16 which in turn were reacted with N,N'‐carbonyldiimidazole to yield benzoxazolones 11 and 17, respectively. Catalytic reduction of 2‐nitro‐4‐(4‐pyridinyl)benzeneamine (18) gave 4‐(4‐pyridinyl)benzene‐1,2‐diamine (19) which was reacted with orthoesters, urea, tetraethoxymethane, and N,N'‐di(carbomethoxy)methylpseudothiourea to give the corresponding benzimidazole derivatives 20, 21, 22, and 23.
Fused s‐triazino heterocycles. XVII. 8,13‐Dihydro‐1,3,7,8,13c‐pentaazabenzo[de]naphthacene, 7H‐1,3,7,8,11b,12,14‐heptaazadibenzo[de,hi]naphthacene and 8H‐1,3,7,8,13,14c‐hexaazabenzo[4,5]cyclohepta[1,2‐a]phenalene, three new ring systems
Authors: Shaw John T. , Corbett Wendy L. , Cuny Gregory D. , Egler Mallory F. , Peciulis Victoria S.
Published: March 2009

The reaction of 7,9‐dibromo‐5‐tribromornethyl‐2‐t‐butyl‐4‐cyano‐1,3,6,9b‐tetraazaphenalene (1a) with p‐toluidine is shown to give 4,6‐dibromo‐2‐t‐butyl‐8,13‐dihydro‐13‐imino‐11‐methyl‐1,3,7,8,13c‐pentaazabenzo[de]naphthacene (4) in two steps with 7,9 dibromo‐2‐t‐butyl‐4‐cyano‐5‐p‐toluidino‐1,3,6,9b‐tetraazaphenalene (2b) as the intermediate product. A related annulation reaction of 1a with N‐(5‐amino‐2,4‐dimethylphenyl)trimethylacetamide (8) leads in two steps to 9,11‐dibromo‐2,13‐di‐t‐butyl‐4,6‐dimethyl‐7H‐1,3,7,8,11b,12,14‐heptaazadibenzo[de,hi]naphthacene (6) with 7,9‐dibromo‐2‐t‐butyl‐4‐cyano‐5N‐(2,4‐dimethyl‐5‐trimethylacetamidophenyl)amino‐1,3,6,9b‐tetraazaphenalene (2d) as the intermediate product. In a similar fashion the reaction of 1a with o‐phenylenediamine forms 14‐amino‐4,6‐dibromo‐2‐t‐butyl‐8H‐1,3,7,8,13,14c‐hexaazobenzo[4,5]cyclohepta[1,2‐a]‐phenalene (12) by way of the intermediate 5‐N‐(2‐aminophenyl)amino‐7,9‐dibromo‐2‐t‐butyl‐4‐cyano‐1,3,6,9b‐tetraazaphenalene (2e). The preparation of N‐(2,4‐dimethyl‐5‐nitrophenyl)‐trimethylacetamide (11) and its reduction to N‐(5‐amino‐2,4‐dimethylphenyl)trimethylacetamide (8) is also described.
A novel approach to the pyrido[4,3‐c]pyridazine ring. Synthesis of pyrido[4,3‐c]pyridazin‐5(6H)‐one from 3,4‐disubstituted pyridazines
Authors: Vors Jean‐Pierre
Published: March 2009

The synthesis of new pyrido[4,3‐c]pyridazin‐5(6H)‐one from ethyl 3‐methyl‐4‐pyridazinecarboxylate using an enamination/ring closure sequence is described. The starting material is easily available from a hetero Diels‐Alder reaction between a 1,2‐diaza‐1,3‐diene and ethyl vinyl ether and oxidation of the resulting 1,4,5,6‐tetrahydropyridazine.
Compounds with potential second order non‐linear optical activity
Authors: Katritzky Alan R. , Rao M. Suresh Chander , Stevens John
Published: March 2009

The synthesis is described of 1,4‐diazabicyclo[2.2.2]octane and piperazine derivatives of potential interest for second‐order NL optical activity.
Competitive free radical 4‐nitrophenylation of pyridine and thiophene
Authors: Klemm L. H. , Dorsey James
Published: March 2009

Competitive free radical 4‐nitrophenylation of pyridine and thiophene shows a relative reactivity of thiophene:pyridine of 1.3:1 as based on product isolation. A three‐center reaction is proposed to account for the predominance of alpha substitution in each system. Column chromatography and 1H nmr are used for separation and identification of products.
Synthesis and cytotoxic activity of 2‐dialkylamino‐alkyl‐1,3‐dihydropyrrolo[3,4‐c]quinoline‐1,3‐diones and 6‐(2‐dimethylaminoethyl)‐1H‐dibenz[c,e]azepine‐5,7‐dione
Authors: Ganjian I. , Khorshidi M. , Lalezari I.
Published: March 2009

The title compounds were synthesized. Cyclodehydration of aromatic 1,2‐dicarboxylic acids, in the presence of dicyclohexylcarbodiimide, to the corresponding N‐substituted imides is discussed. Compounds 8 and 10 were tested in vitro against K562 and HL‐60 cell lines. Compound 10 exhibited moderate cytotoxic activity.
Synthesis and stereochemistry of stereoisomeric 1,3‐benzoxazino‐1,3‐ and ‐3,1‐benzoxazines
Authors: Lázár László , Fülöp Ferenc , Bernáth Gábor , Kálmán Alajos , Argay Gyula
Published: March 2009

Partly saturated 3,1‐benzoxazino[1,2‐c][1,3]benzoxazines and 1,3‐benzoxazino[3,2‐c][1,3]benzoxazines were prepared in one‐pot syntheses from different cyclic 1,3‐aminoalcohols by treatment with salicylaldehyde or 5‐bromosalicylaldehyde, followed by formaldehyde. The structures of tetracycles 3a and 5 were determined by means of X‐ray diffraction.
Benzofurans. Improved syntheses of bufuralol, 7‐ethyl‐2‐(2‐tert‐butylamino‐1‐hydroxyethyl)benzofuran, and 1″‐oxobufuralol, 7‐acetyl‐2‐(2‐tert‐butylamino‐1‐hydroxyethyl)benzofuran
Authors: Weerawarna S. Ananda , Guha‐Biswas Michael , Nelson Wendel L.
Published: March 2009

An improved laboratory scale synthesis of bufuralol (1) and 1″‐oxobufuralol (4) was accomplished. The intermediate benzofurans were prepared via aromatization of 2,3‐dihydrobenzofurans or by a one‐step acidcatalyzed cyclization from 2,2‐diethoxyethyl 4‐bromo‐6‐ethyl‐2‐formylphenyl ether (23). Base‐catalyzed cyclization of 3‐(5‐bromo‐3‐ethyl‐2‐hydroxyphenyl)‐1.2‐epoxypropane (16) provided the key intermediate, 5‐bromo‐7‐ethyl‐2‐hydroxymethyl‐2,3‐dihydrobenzofuran (17). Selective functionalization of the C‐2 and C‐7 positions of the benzofuran ring system was accomplished to afford both 1 and 4.
Reaction of lumichrome or 2‐thiolumichrome with alkylamines
Authors: Ueda Taisei , Asahi Masumi , Nagai Shin‐Ichi , Sakakibara Jinsaku
Published: March 2009

The reaction of lumichrome (2) with alkyl (or allyl)amines such as n‐butylamine, n‐hexylamine and allylamine gave 2,3‐disubstituted 6,7‐dimethylquinoxalines 4a‐d, 5a‐d, 6a‐d, 7a‐d and 8a‐d. Similar reaction of 2‐thiolumichrome (3) with alkyl (or allyl)amines gave 2,3‐disubstituted 6,7‐dimethylquinoxalines 6a‐c, 9a‐c and 10a‐c, 2‐alkyl (or allyl)amino‐6,7‐dimethyl‐3,4‐dihydrobenzo[g]pteridine‐4‐ones 11a‐c and 2,4‐dialkyl (or allyl)amino‐6,7‐dimethylbenzo[g]pteridines 12a‐c.
Substituent effects in the conversion of azido‐ and diazidotrinitrobenzenes to benzofuroxans and difuroxans
Authors: Chaykovsky Michael , Adolph Horst G.
Published: March 2009

The preparation of a number of substituted dinitrobenzofurazan oxides (dinitrobenzofuroxans) and nitrobenzobis(oxadiozoles) (nitrobenzodifuroxans), in which the substituents were amino, fluoro, formamido, hydroxy, and ureido groups, by thermolysis of azido precursors is described. The ease of thermolysis appears to be an inverse function of the angle of twist of the nitro groups ortho to the azido group from the plane of the benzene ring. Amino‐ and hydroxy‐substituted dinitrobenzofuroxans and nitrobenzodifuroxans were found to be much more stable than their non‐nitro‐substituted counterparts.
Chemistry of thienopyridines. XL. Reactions of 7‐acetyl‐4‐(1‐carboethoxy‐1‐cyano)methylene‐4,7‐dihydrothieno‐[2,3‐b]pyridine. Part 3: Kinetics of hydrolysis
Authors: Klemm L. H. , Lu Jennifer J.
Published: March 2009

The kinetics of hydrolysis of 7‐acetyl‐4‐(1‐carboethoxy‐1‐cyano)methylene‐4,7‐dihydrothieno[2,3‐b]pyridine (1) in undried DMSO‐d6 to give ethyl 2‐(4‐thieno[2,3‐b]pyridyl)cyanoacetate and acetic acid at ambient temperature was investigated by 1H nmr spectrometry. The reaction is pseudo first order in the concentration of 1 with a rate constant of 9 × 10−4 per minute, not noticeably altered by the addition of deuteriotrifluoroacetic acid. The hydrolysis is, however, catalyzed by means of added pyridine‐d5 (k = 37 × 10−4 per minute). The pyridine is presumed to serve as a transfer agent for the acetylium ion as in acetylations with acetyl chloride and acetic anhydride.
Synthesis and biological activities of substituted dihydrobenzo[h]‐pyrimido[4,5‐b]quinolines as tetracyclic 5‐deaza nonclassical folates
Authors: Donkor Isaac O. , Gangjee Aleem , Kisliuk R. L. , Gaumont Y.
Published: March 2009

Novel tetracyclic compounds 1–4 have been synthesized via a regiospecific cyclocondensation reaction between substituted 6‐aminopyrimidines 5–7 and chlorovinyl aldehydes 13 and 14. The linear structures of these compounds were established by 1H nmr and 13C nmr spectral data and also by synthesis of the compounds via an unambiguous route. The growth of Manca human lymphoma cells was inhibited 50% by 1 and 4 at 4.5 × 10−6 M and 1.2 × 10−6 M respectively. These compounds also inhibited human dihydrofolate reductase (DHFR)by 50% at 4.4 × 10−6 M and 1.4 × 10−6 irrespectively and L. casei DHFR at 1.9 × 10−5 M and 1.1 × 10−5 M respectively. Compound 16, a positional isomer of 1, was the most potent of the compounds studied, it inhibited the growth of Manca human lymphoma cells by 50% at 9 × 10−8 M. The IC50 values of 16 for the inhibition of human DHFR and L. casei DHFR were 8 × 10−8 M and 1.9 × 10−5 M respectively.
Heterocyclic tautomerism. V. 2‐Guanidinobenzimidazole
Authors: Steel Peter J.
Published: March 2009

A single‐crystal X‐ray structure analysis of 2‐guanidinobenzimidazole shows the molecule exists in the solid state as tautomer 1, with an intramolecular hydrogen bond between the benzimidazole‐N3 and a guanidino‐NH2. The guanidino group is inclined at an angle of 13.8° to the benzimidazole plane. Other nitrogen atoms and their attached hydrogens are involved in additional intermolecular hydrogen bonds that connect the molecules in a complex three‐dimensional network.
Synthesis of 5,6,8,9,14,14a‐hexahydroisoquino[1,2‐b][3]benzazepines
Authors: Kim Dong H.
Published: March 2009

Syntheses of 5,6,8,9,14,14a‐hexahydroisoquino[1,2‐b][3]benzazepine‐2,3,11,12‐tetrol and related compounds are described. Key steps involve an initial construction of the isoquinoline ring under the Bischler‐Napieralski conditions, which is followed by the building of the azepine ring via an intramolecular lactam formation on to the isoquinoline nucleus.
Synthesis of condensed quinoxalines. Part II
Authors: Sabnis R. W. , Rangnekar D. W.
Published: March 2009

A novel efficient synthesis of fluorescent, fused quinoxalines was achieved. 7‐Triazolyl‐1,4‐dioxino[2,3‐b]‐quinoxalines were synthesized by the diazotisation of 7‐amino‐1,4‐dioxino[2,3‐b]quinoxaline and coupling with selected aromatic amines followed by air oxidation. Diazotised aryl amines were coupled with 7‐amino‐1,4‐dioxino[2,3‐b]quinoxalines followed by subsequent air oxidation afforded 1,4‐dioxino[2,3‐b]quinoxalino‐[6,5‐d]1,2,3‐triazoles. 7‐Amino‐1,4‐dioxino[2,3‐b]quinoxaline was condensed with conjugated enol ethers followed by cyclization in dowtherm resulted in 1,4‐dioxino[2,3‐b]quinoxalino[6,5‐b]pyridines.
The effect of fused heterocycles on the liquid crystalline properties of di(alkoxy‐substituted‐phenyl)pyridazines and di(alkoxy‐substituted‐phenyl)pyridines
Authors: Mataka Shuntaro , Misumi Osamu , Lin Wei Hua , Tashiro Masashi , Takahashi Kazufumi , Tori‐I Akiyoshi
Published: March 2009

Di(alkoxy‐substituted‐phenyl)pyridines and di(alkoxy‐substituted‐phenyl)pyridazines annelated with heterocycles such as imidazole, triazole, pyrazine, and 1,2,5‐oxa(thia)diazole were prepared and the effect of the fused heterocycles on the liquid crystalline properties were investigated.
Synthesis of soluble quinacridones
Authors: Kitahara Kiyoshi , Yanagimoto Hiromitsu , Nakajima Namiko , Nishi Hisao
Published: March 2009

The synthesis of 4,11‐dialkylthioquinacridones and 5,12‐dialkyl‐4,11‐dialkylthioquinacridone from o‐alkylthioanilines and diethyl 2,5‐dioxo‐1,4‐cyclohexanedicarboxylate is described. These compounds are easily soluble in organic solvents in contrast to unsubstituted quinacridone.
A Convenient and efficient method for the preparation of 6‐Acyl‐2(3H)‐benzoxazolones
Authors: Aichaoui Hocine , Lesieur Daniel , Hénichart Jean‐Pierre
Published: March 2009

Benzoxazolinone derivatives have been found to exhibit various pharmacological properties and 6‐acyl‐2(3H)‐benzoxazolones are considered as key starting materials for the preparation of these compounds. Reported here are the optimal conditions for a regioselective acylation at the 6‐position of the benzoxazolinone ring. A general method leading to the expected products in excellent yields consists in using a mixture of aluminum chloride‐dimethylformamide as catalyst and acid anhydrides or chlorides as acylating agents.
Peri‐selective photocycloadditions of methyl 2‐pyrone‐5‐carboxylate with unsaturated cyclic ethers
Authors: Shimo Tetsuro , Iwakiri Tsuneaki , Somekawa Kenichi , Suishu Takaaki
Published: March 2009

Photosensitized cycloaddition reaction of methyl 2‐pyrone‐5‐carboxylate (1) with 2,3‐dihydrofuran gave cis‐ exo‐ and cis‐endo‐[2 + 2] cycloadducts across the C3‐C4 double bond in 1, and a [4 + 2] cycloadduct which was different in addition‐orientation from the Diels‐Alder adducts. Each [2 + 2] cycloadduct was obtained by the use of sensitizers having different triplet energies. Photosensitized reactions of 1 with 3,4‐dihydro‐2H‐pyrans afforded cis‐endo‐[2 + 2] cycloadducts, respectively. The photocycloaddition mechanism was also explained from the excited state of 1 calculated by means of MNDO‐Cl method.
Products formed by the reaction of o‐diacylbenzenes with primary amines
Authors: Nan'Ya Seiko , Kitahara Takeo , Butsugan Yasuo
Published: March 2009

The reactions of o‐diacylbenzenes with primary amines or ammonia produced several isoindole derivatives in the presence or the absence of acid. From o‐diacylbenzenes and hydroxylamine hydrochloride in the presence of triethylamine 1H‐2,3‐benzoxazine derivatives were obtained.
Total assignment of the proton and carbon NMR spectra of 5′‐NOR‐anhydrovinblastine
Authors: Spitzer Timothy D. , Crouch Ronald C. , Martin Gary E.
Published: March 2009

Total spectral assignment of the bis‐indole alkaloid Navelbine®, 5′‐nor‐anhydrovinbIastine, was accomplished using a combination of two‐dimensional nmr techniques. Conventional homonuclear and inverse‐detected experiments were supplemented with the HMQC‐TOCSY experiment to unequivocally assign carbons directly bound to overlapped protons. In addition, the recently introduced GEM‐COSY experiment was evaluated as a technique for the identification of geminal methylene pairs. Partial assignments proposed by Potier and co‐workers, based on chemical shift considerations, are largely in agreement with the unequivocal assignments determined in this study.
Benzofuran derivatives. Part 4, synthesis of benzofurans and 2,3,4,5‐tetrahydro‐1‐benzoxepin‐3,5‐diones
Authors: Suzuki Tsuneo , Tanemura Kiyoshi , Horaguchi Takaaki , Shimizu Takahachi , Sakakibara Tohru
Published: March 2009

By treatment of ethyl 4‐ or 5‐substituted 2‐acetylphenoxyacetates 1 with potassium hydroxide in dry dioxane, benzofurans 2–7 and 2,3,4,5‐tetrahydro‐1‐benzoxepin‐3,5‐diones 8 were obtained. The relative yields of benzofurans 2–7 and 2,3,4,5‐tetrahydro‐1‐benzoxepin‐3,5‐diones 8 varied with the types of 4‐ or 5‐substituents. The electron‐donating 4‐methoxyl group favored the formation of benzoxepins. On the other hand, electron‐withdrawing substituents such as the 4‐nitro group favored the formation of benzofurans. When esters 1 were treated with sodium amide, 2,3‐dihydrobenzofurans 2 were obtained exclusively regardless of 4‐ or 5‐substituents.
Synthesis of optically active 2‐benzyldihydrobenzopyrans for the hypoglycemic agent englitazone
Authors: Urban Frank J. , Moore Bernard S.
Published: March 2009

Two syntheses of some optically active 2‐benzyl‐2,3‐dihydro‐4H‐benzopyrans and benzopyran‐4‐ones are presented. An asymmetric synthesis starting from D‐ and L‐phenylalanine was used to provide both enantiomers of 2‐benzyl‐6‐(methoxycarbonyl)‐2,3‐dihydro‐4H‐benzopyran‐4‐one 19. Phenylalanine was diazotized in aqueous sulfuric acid to 2‐hydroxy‐3‐phenylpropionic acid 6 which was converted in four steps to 1‐bromo‐2‐(4‐methoxycarbonylphenoxy)‐3‐phenylpropane 11. (4R,S)‐Benzamido‐2‐benzyl‐2,3‐dihydro‐6‐(methoxycarbonyl)‐4H‐1‐benzopyran‐4‐carboxylic acid 16 was prepared from 11 by amidoalkylation with α‐hydroxyhippuric acid in methanesulfonic acid solution followed by spiroalkylation to (4R,S)‐2‐benzyl‐2,3‐dihydro‐6‐(methoxycarbonyl)spiro[4H‐benzopyran‐4,4′‐2′‐phenyloxazolidin]‐5′‐one 15. After the phenyloxazolidin‐5‐one 15 was hydrolyzed to the spirobenzamido carboxylic acid 16, oxidative decarboxylation with sodium hypochlorite yielded optically active 2‐benzyl‐6‐(methoxycarbonyl)‐2,3‐dihydro‐4H‐benzopyran‐4‐one 19. The ketone in 19 was reduced by hydrogenation over palladium on carbon to a methylene group and the ester was converted to the aldehyde to give both isomers of the desired intermediate 2‐benzyl‐6‐(formyl)‐2,3‐dihydro‐4H‐benzopyran 25. The second synthesis relied on an enzymatic hydrolysis of ethyl 2,3‐dihydrobenzopyran‐2‐carboxylate 27 with the lipase from P. fluorescens to provide the desired 2R‐ester. The ester group in (R)‐27 was converted to the triflate (R)‐29. Displacement of the triflate group with phenylmagnesium bromide and cuprous bromide as catalyst gave 2R‐benzyl‐2,3‐dihydro‐4H‐benzopyran (R)‐30. Formylation of (R)‐30 provided 2R‐benzyl‐6‐(formyl)‐2,3‐dihydro‐4H‐benzopyran (R)‐25 identical with that from the first synthesis. These optically active intermediates are used in the preparation of the hypoglycemic agent englitazone.
Syntheses of polycyclic‐1,4‐dithiines and related heterocycles
Authors: Matsuoka Masaru , Iwamoto Akihiro , Furukawa Naoyuki , Kitao Teijiro
Published: March 2009

Reactions of dihalogenoquinones or dihalogenoquinoxalines with thioamides gave the corresponding 1,4‐dithiines in high yields. Many of polycyclic 1,4‐dithiin derivatives can be synthesized by the reactions of dihalogenoheterocycles with thioamides, and they are useful as pigments and functional materials for electro‐optical applications. Some of heteroaromatic‐1,4‐dithiins formed an intermolecular charge‐transfer (CT) complex with a π‐acceptor such as TCNQ, and they are useful as π‐donors for CT complex.