bluuebunny/crossref_metadata_2025 huggingface dataset:
Bromination of sydnones. I. Reaction with 3‐arylsydnones containing electron‐donors on the aryl ring
Authors: Turnbull Kenneth
Published: April 2009

Bromination has been examined for a series of 3‐arylsydnones (1) with electron donors (dimethyl to dimethoxy) on the aryl ring. In no example was exclusive aryl ring bromination observed, however, exclusive sydnone ring bromination could be realized in every case. For two dimethoxyphenyl examples both aryl and sydnone ring bromination occurred.
Derivatives of benzo[5,6]cyclohepta[1,2‐b]thiophene. Synthesis of 2,3,7,8‐tetrahydro‐3‐oxothieno[1,2‐b]cyclohepta[5,6,7‐de]isoquinoline and 1,2,3,7,8,11b‐hexahydro‐3‐oxothieno[1,2‐b]cyclohepta[5,6,7‐de]isoquinoline
Authors: Sarriá Eva , Vega Salvador
Published: April 2009

The synthesis of the title compounds was carried out by cyclization via isocyanate of (E)‐4,5‐dihydro‐10H‐benzo[5,6]cyclohepta[1,2‐b]‐thiophene‐10‐ylideneacetic acid and 4,5‐dihydro‐10H‐benzo[5,6]cyclohepta[1,2‐b]‐thiophene‐10‐ylacetic acid respectively, which were obtained by the Wadsworth‐Emmons modification of the Wittig reaction of 4,5‐dihydro‐10H‐10‐oxobenzo[5,6]cyclohepta[1,2‐b]thiophene and triethyl phosphonacetate. The structures of these new compounds are described.
Condensation of enolates with O‐ethyl pyrrolidonium salts: An alternative to the orthoamide condensation
Authors: Mattson Ronald J. , Sowell J. Walter , Bryson Thomas A.
Published: April 2009

O‐Ethyl‐N‐substituted pyrrolidonium fluoroborate salts were condensed under basic conditions with active methylene compounds to give vinylogous carbamates and cyanamides.
Natural abundance 17O NMR spectroscopy of heterocyclic N‐oxides and Di N‐oxides. Structural effects
Authors: Boykin D. W. , Balakrishnan P. , Baumstark A. L.
Published: April 2009

The 17O chemical shift data for a series of azine N‐oxides, diazine N‐oxides and di‐N‐oxides at natural abundance are reported. Isomeric methyl substituted quinoline N‐oxides exhibited chemical shifts which are interpreted in terms of electronic and compressional effects. The 17O chemical shift for 8‐methylquinoline N‐oxide (370 ppm) is deshielded by 25 ppm more than predicted, based upon electronic considerations. The 17O chemical shift for the N‐oxide of 8‐hydroxyquinoline (289 ppm) is substantially shielded as a result of intramolecular hydrogen bonding. The relative 17O chemical shifts for diazine N‐oxides of pyrazine, pyridazine and pyrimidine follow predictions based on back donation considerations. Because of solubility limitations, spectra of only two N,N′‐dioxides were obtained. The chemical shift of benzopyrazine di N‐oxide in acetonitrile was shielded by 18 ppm compared to that of its mono N‐oxide.
Reactivity of some 3‐substituted derivatives of 2,6‐dihalogenopyridines towards potassium amide in liquid ammonia [a]
Authors: Streef J. W. , Den Hertog H. J. , Van Der Plas H. C.
Published: April 2009

Reactions of 2,6‐dichloro‐3‐phenyl‐, 2,6‐dibromo‐3‐phenyl‐, 2,6‐dichloro‐3‐dimethylamino‐ and 2,6‐dibromo‐3‐dimethylaminopyridine with potassium amide in liquid ammonia were investigated. Whereas 2,6‐dichloro‐3‐phenylpyridine yields 4‐amino‐2‐benzylpyrimidine, from 2,6‐dibromo‐3‐phenylpyridine as a product of a novel ring fission 2‐amino‐l‐cyano‐l‐phenyl‐but‐l‐en‐3‐yne was isolated, together with 4‐amino‐6‐bromo‐3‐phenylpyridine and 2,6‐diamino‐3‐phenylpyridine. It was shown that neither 2‐amino‐6‐bromo‐3‐phenyl‐ nor 6‐amino‐2‐bromo‐3‐phenylpyridine are intermediates in the formation of the 2,6‐diamino derivative, as these bromo compounds are transformed in the basic medium into 1,3‐dicyano‐l‐phenylpropene. From both 2,6‐di‐chloro‐3‐dimethylamino‐ and 2,6‐dibromo‐3‐dimethylaminopyridine mixtures are obtained from which only 2‐amino‐l‐cyano‐l‐dimethylamino‐but‐l‐en‐3‐yne and 4‐amino‐6‐halogeno‐3‐dimethylaminopyridine were isolated.

Mechanisms for the reactions studied are proposed, i.e. a SN(ANRORC) mechanism for the aminodebromination of 2,6‐dibromo‐3‐phenylpyridine into the corresponding 2,6‐diamino compound.
Mannich base derivatives of bioactive benzyl‐1,3‐benzodioxo‐5‐ols
Authors: Jurd Leonard
Published: April 2009

3,4‐Methylenedioxyphenol (sesamol) reacts with equimolecular quantities of an aromatic aldehyde and morpholine or piperidine in methanol to give Mannich bases 7 and 8, related to insect growth regulators and anti‐leukemic and antimitotic benzyl‐1,3‐benzodioxole derivatives.
Réaction de l'acide chromone‐2 carboxylique avec les carbodiimides: Synthèse de spiro [(chromanone‐4)‐2: 5′‐hydantoïnes]
Authors: Filliatre Claude , Servens Et Christian
Published: April 2009

La réaction de l'acide chromone‐2 carboxylique avec des carbodiimides donne des N‐acylurées. Ces N‐acylurées se cyclisent facilement pour conduire aux spirochromanones correspondantes.
New synthesis of 5,6,7,8‐tetrahydro‐4H‐thieno[2,3‐d]azepine
Authors: Fréhel Daniel , Badorc Alain , Pereillo Jean‐Marie , Maffrand Jean‐Pierre
Published: April 2009

This paper describes two new access routes to 5,6,7,8‐tetrahydro‐4H‐thieno[2,3‐d]azepine from 2‐(2‐thienyl)ethylamine or its N‐(2‐chlorobenzyl) derivative. One of these two syntheses involves a new ring expansion from a 6,7‐dihydro[3,2‐c]pyridinium derivative, chloromethylated in position 4.
Substitution in the hydantoin ring. Part IX. N‐cyanohydantoins
Authors: Zinczuk Juan , Orazi Orfeo O. , Corral Renée A. , Roncaglia Hugo
Published: April 2009

The N1‐and N3‐cyanohydantoins, a new series of derivatives, were prepared by reaction of the parent hydantoin with a base and a cyanogen halide. Analysis of ir, pmr, and mass spectral data allowed the assignment of ring position‐3 to the cyano group in derivatives IIa,b of 1,3‐unsubstituted hydantoins. 3‐Cyanohydantoins can transfer the cyano substituent to strong nucleophiles via an addition‐elimination process.
Synthetic antibacterials. VIII. 7‐(1′‐alkylhydrazino)‐1,8‐naphthyridines and related compounds
Authors: Nishigaki Sadao , Mizushima Noriko , Kanazawa Hashime , Ichiba Misuzu , Senga Keitaro
Published: April 2009

Synthesis and in vitro antibacterial activity of 7‐(1′‐alkylhydrazino)‐1,8‐naphthyridines related to nalidixic acid were investigated. Namely, treatment of 7‐alkylamino‐1‐ethyl‐1,4‐dihydro‐4‐oxo‐1,8‐naphthyridine‐3‐carboxylic acids 1a‐d with sodium nitrite in the presence of hydrochloric acid gave the 1‐ethyl‐1,4‐dihydro‐7‐(N‐nitrosoalkylamino)‐4‐oxo‐1,8‐naphthyridine‐3‐carboxylic acids 2a‐d, which upon reacting with zinc dust in acetic acid gave the 7‐(1′‐alkylhydrazino)‐1‐ethyl‐1,4‐dihydro‐4‐oxo‐1,8‐naphthyridine‐3‐carboxylicacids 3a‐d. The compound 3a was alternately obtained by the reaction of 7‐chloro‐1‐ethyl‐1,4‐dihydro‐4‐oxo‐1,8‐naphth‐yridine‐3‐carboxylic acid (4) with methylhydrazine. The reaction of 7‐chloro‐4‐hydroxy‐1,8‐naphthyridine‐3‐carboxylic acid (5) with methylhydrazine gave the 4‐hydroxy‐7‐(1′‐methylhydrazino)‐4‐oxo‐1,8‐naphthyridine‐3‐carboxylic acid (6), which upon treatment with alkyl halides afforded the 1‐alkyl‐1,4‐dihydro‐7‐(1′‐methyl‐hydrazino)‐4‐oxo‐1,8‐naphthyridines 3a and 3e‐g. The reaction of the appropriate 3 with ketones gave the corresponding 7‐(1′‐methylalkylidenehydrazino)‐1,8‐naphthyridines 7a‐c and 8a‐b. Among the compounds prepared, certain 3 and 7 exhibited good activity against Gram‐negative bacteria.
A regiospecific synthesis of 1‐methylamino‐6‐fluoro‐7‐(4‐methylpiperazin‐1‐yl)‐1,4‐dihydro‐4‐oxoquinoline‐3‐carboxylic acid
Authors: Chu Daniel T. W.
Published: April 2009

An efficient and regiospecific synthesis of 1‐methylamino‐6‐fluoro‐7‐(4‐methylpiperizin‐1‐yl)‐1,4‐dihydro‐4‐oxoquinoline‐3‐carboxylic acid (3) via an intramolecular nucleophilic displacement cyclization reaction is reported.
Syntheses of isomers of protoporphyrin‐IX with permuted propionic side‐chains
Authors: Smith Kevin M. , Pandey Ravindra K.
Published: April 2009

Total syntheses of hemins with permutations of the propionic side‐chains in the C and D rings (compared with protoporphyrin‐IX) are described. The products, 3, 2 and 4, are the dimethyl esters of protoporphyrins ‐I, ‐XI, and ‐XIV, respectively. They are of interest in connection with nmr studies designed to elucidate the structural features of the heme crevice in myoglobin and the effect of structural modifications of the C and D rings on the kinetics of heme‐apoprotein reconstitutions, as well as studies of substrate specificity of the heme degradation enzyme, heme oxygenase.
Synthesis of new 1,2,4‐triazolo[4,3‐b]pyridazines and related compounds
Authors: Sircar Ila
Published: April 2009

The synthesis of novel 6‐[4‐(1H‐imidazol‐1‐yl)phenyl]‐1,2,4‐triazolo[4,3‐b]pyridazines 8a‐f and related compounds is described. Although the intermediate hydrazine derivatives 7 and 9 possess good positive inotropic activity, the fused bicyclic pyridazines 8a‐f are significantly less potent than the 3(2H)‐pyridazinone 5. Compounds 8a‐f are potent but nonselective inhibitors of cardiac phosphodiesterase.
The reactivity of 2,3‐diaminopyridine toward alkyl chloroformates and dicarbonates
Authors: Zecchini Giampiero Pagani , Torrini Ines , Paradisi Mario Paglialunga
Published: April 2009

The reaction of 2,3‐diaminopyridine (DAP) with alkyl chloroformates and dialkyl dicarbonates is affected by the nature of the acylating agent and the acylation conditions. Mono and dicarbamates of DAP were obtained using chloroformates, while the formation of alkoxycarbonyl derivatives of imidazo[4,5‐b]pyridin‐2‐one was observed when the reaction with dicarbonates was performed at room temperature in THF‐pyridine. Our procedure for the synthesis of imidazopyridin‐2‐ones represents an improvement over the previous methods which require rather severe conditions. The revised structure for a monoacetyl derivative of the above bicyclic system is also reported.
The chemistry of 2H‐3,1‐benzoxazine‐2,4(1H)‐dione (isatoic anhydride). 18. A short synthesis of swietenidin A
Authors: Coppola Gary M.
Published: April 2009

N‐Methylisatoic anhydrides react with the lithium enolate of ethyl methoxyacetate at low temperatures to produce intermediates which, when cyclized, afford 4‐hydroxy‐3‐methoxy‐2(1H)‐quinolinones. By this route, 3‐methoxy‐N‐methylisatoic anhydride (8) can be converted to the alkaloid swietenidin A (2) in 71% yield.
Synthesis and anticonvulsant evaluation of 1‐amino‐1,3‐dihydro‐2H‐benzimidazol‐2‐ones
Authors: Kornet M. J. , Beaven W. , Varia T.
Published: April 2009

1‐Amino‐2‐benzimidazolinones containing alkyl substituents on the amino nitrogen have been prepared by the sodium bis (2‐methoxyethoxy)aluminum hydride reduction of 1‐acylamino‐2‐benzimidazolinones. The latter compounds were obtained in two steps from o‐nitro‐β‐acylphenylhydrazines. All of the 1‐amino‐2‐benzimidazolinones exhibited activity in the standard anticonvulsant tests except for the 1‐benzylamino compound. The most active compound was 1‐ethylamino‐2‐benzimidazolinone which protected mice in the maximal electroshock seizure test at 30 mg/kg.
The mass spectra of small‐ring heterocycles. IV
Authors: Tarburton Philip , Sun Tung , Gross Michael L. , Cromwell Norman H.
Published: April 2009

Both the high and low resolution mass spectra of fourteen isomeric trans‐ and cis‐aroylaziridines are presented. In contrast to earlier low resolution mass spectral work on these compounds [1], a new fragmentation pathway for the loss of hydroxyl is presented. Also, the simple fission of the N‐alkylnitrogen bond is described. Detailed fragmentation mechanisms are presented and discussed for the major ions found in the mass spectra.
Synthesis of 4,5‐dihydro‐4‐phenyl‐3H‐1,3,4‐benzotriazepines
Authors: Martin Lawrence L. , Agnew Marc N. , Setescak Linda L.
Published: April 2009

Several 4,5‐dihydro‐4‐phenyl‐3H‐1,3,4‐benzotriazepines were synthesized by conversion of 1‐[(2‐nitrophenyl)methyl]‐1‐phenylhydrazine to either 1‐[(2‐aminophenyl)methyl]‐1‐phenylhydrazine or 1‐[(2‐aminophenyl)‐methyl]‐2‐methyl‐1‐phenylhydrazine. Ring closure of these intermediates with triethyl orthoacetate or triethyl orthopropionate gave the title compounds in overall yields of 40‐60%.
Synthesis and X‐Ray crystal structure of a 2,4,5‐trisubstituted 1,2,4‐triazolin‐3‐one
Authors: Madding Gary D. , Smith David W. , Sheldon Robert I. , Lee B.
Published: April 2009

The synthesis and x‐ray crystal structure of BMY 13754, a 1,2,4‐triazolin‐3‐one under clinical evaluation as an antidepressant agent, is described. Several synthetic strategies are discussed.
Synthesis of some 3‐alkenyl‐4‐oxo‐6,7‐dihydro‐4H‐pyrano[3,4‐d]isoxazoles
Authors: Chantegrel Bernard , Nadi Abdel‐Ilah , Gelin Suzanne
Published: April 2009

A series of 3‐alkenyl‐4‐oxo‐6,7‐dihydro‐4H‐pyrano[3,4‐d]isoxazole derivatives was prepared by reaction of hydroxylamine with 4,5‐dioxo‐2,3,7,8‐tetrahydro‐4H,5H‐pyrano[4,3‐b]pyran derivatives.
Synthesis of the 7‐deaza and 5‐aza‐7‐deaza purine analogs of the antiherpes agent 9‐[(1,3‐dihydroxy‐2‐propoxy)methyl]guanine (DHPG)
Authors: Mcgee Danny P. C. , Martin John C. , Verheyden Julien P. H.
Published: April 2009

Synthesis of 2‐amino‐7‐[(1,3‐dihydroxy‐2‐propoxy)methyl]pyrrolo[2,3‐d]pyrimidin‐4‐one (3) a 7‐deaza purine analogue and 2‐amino‐8‐[(1,3‐dihydroxy‐2‐propoxy)methyl]imidazo[1,2‐a]‐s‐triazin‐4‐one (4) a 5‐aza‐7‐deaza purine analogue of DHPG (2) are reported.
Base strengths and polarographic behaviour of a number of pyrazine derivatives
Authors: Gumbley Stewart J. , Lee T. W. S. , Stewart Ross
Published: April 2009

The pK1 and pK2 values and the Polarographic half‐wave reduction potentials for a series of methyl substituted pyrazines are reported, together with the reduction potentials of several of their N‐alkyl derivatives. There is a linear inverse relationship between pK1 and E1/2 for the pyrazines.
Synthesis of some 2‐(heteroarylamino)benzimidazoles and their cyclization with phosgene
Authors: Bossio Ricardo , Marcaccini Stefano , Parrini Valerio , Pepino Roberto
Published: April 2009

2‐(Benzimidazol‐2‐ylamino)pyridine (4a), 2‐(benzimidazol‐2‐ylamino)pyrazine (4b), and 2‐(benzimidazol‐2‐ylamino)thiazole (4c) underwent a ring‐closure reaction on treatment with phosgene affording 6H‐pyrimido‐[1′,2′:5,4][1,3,5]triazino[1,2‐a]benzimidazol‐6‐one (1a), 6H‐pyrazino[1′,2′:5,4][1,3,5]triazino[1,2‐a]benzimidazol‐6‐one (1b), and 5H‐thiazolo[2′,3′:4,5][1,3,5]triazino[1,2‐a]benzimidazol‐5‐one (1c) respectively. The structure of these hitherto unknown heterocyclic systems was confirmed by their ir and mass spectra.
New agents for alkoxycarbonylation of amines
Authors: Ohta Akihiro , Inagawa Yukiko , Inoue Masami , Shimazaki Makoto , Mamiya Yukari
Published: April 2009

Alkoxycarbonylated pyrazinols and pyrazinethiols were prepared. These compounds were shown to be convenient agents for alkoxycarbonylation of aliphatic amines.
Elektronenreiche olefine mit pyran‐4‐yliden‐einheit
Authors: Krasuski Witold , Regitz Manfred
Published: April 2009

Für die Synthese der bisher unbekannten elektronenreichen Olefine mit einer Pyran‐4‐yliden‐Einheit werden zwei Wege beschritten:

1) Pyryliumsalze (6a‐c) werden mit 2‐Piperidino‐1,3‐dithiolen (5a,b) zu 2‐(Pyran‐4‐yliden)‐1,3‐dithiolen (7a‐f) in Acetonitril bei 70° kondensiert. Auf analogem Wege werden die 2‐(Pyran‐4‐yliden)‐1,3,4‐thiadiazoline 13a‐f erhalten.

2) Pyryliumsalze (6a‐c) werden über die (Pyran‐4‐yl)‐phosphoniumsalze 8a‐c in die (Pyran‐4‐yliden)‐phosphorane 9a‐c umgewandelt, die mit Dithioliumsalzen (10a,b) die Olefine 7a,c,e und g‐i liefern. Umsetzung von 9a,b mit den Thiadiazoliumsalzen 14a,b macht 13a‐c zugänglich.
Synthesis of 2‐isopropylidenehydrazinylthiazole and its subsequent annelation to the corresponding thiazolo[2,3‐c]‐s‐triazole
Authors: Houssin Raymond , Bernier Jean‐Luc , Hénichart Jean‐Pierre
Published: April 2009

An unequivocal synthesis of a new thiazolo[2,3‐c]‐s‐triazole substituted at the C‐5 position by a very useful methyl triphenylphosphonium salt has been achieved starting from the corresponding 2‐isopropylidenehydrazinylthiazole and formic acid. Ring closure was found to be very easy without isolation of a formylhydrazino intermediate. The thiazole derivative was prepared from isopropylidenethiosemicarbazide and (3‐chloro‐2‐oxo)propyltriphenylphosphonium chloride in a good yield.
Addition of 3‐thienyllithium to phthalic anhydride: A simple method for the synthesis of 9,10‐dihydro‐4H‐benzo[4,5]cyclohepta[1,2‐b]thiophen‐10‐one
Authors: Majchrzak Michal W.
Published: April 2009

Addition of 3‐thienyllithium to phthalic anhydride produces a mixture of materials from which 2‐(3‐thienoyl)benzoic acid was easily separated. Elaboration of the acid side chain and ring closure produced the title compound in good yield.
Synthesis of 2‐(1‐methyl‐4‐piperylid‐3‐ene)‐9,10‐dihydro‐4H‐benzo[4,5]‐ cyclohepta[1,2‐b]thiophen‐10‐one, a new potential antiasthmatic analogue of zaditene
Authors: Majchrzak Michal W.
Published: April 2009

The title compound has been prepared in four steps from readily available starting material. The key reaction is the metallation of 10‐methoxy‐4H‐benzo[4,5]cyclohepta[1,2‐b]thiophene, which occurs exclusively at the desired 2 position.
Bromination of sydnones. II Bromination of 3‐(2‐aminophenyl)sydnone and related compounds
Authors: Hodson Stephen J. , Turnbull Kenneth
Published: April 2009

Bromination of 3‐(2‐aminophenyl)sydnone 2 under a variety of conditions is reported. The products obtained are interrelated by a series of subsequent reactions. One major product is the bromoaryl compound 8, the first example of bromination on the aryl rather than sydnone ring when the two are in competition. Surprisingly, bromoaminosydnone 9, prepared from its nitro analogue, was not among the products obtained by direct bromination of 2.
Synthesis of 8‐substituted naphtho[2,1‐b]thiophenes with cationic side chains at position 4
Authors: Kusuma Srihari , Wilson W. David , Boykin David W.
Published: April 2009

A series of five 8‐substituted α‐[bis(2‐hydroxyethyi)aminoethyl]naphtho[2,1‐b]thiophenes 7 and a series of seven N‐(3‐dimethylaminopropyl)‐8‐substituted naphtho[2,1‐b]thiophene‐4‐carboxamides 8 have been synthesized. The naphtho[2,1‐b]thiophene‐4‐carboxylic acids 4 were prepared by photooxidative cyclization of α‐(2‐thienyi)‐β‐arylacrylic acids 3. The carboxylic acids 4 were converted by a conventional five step route involving α‐bromoketone intermediates to the a‐[bis(2‐hydroxyethyl)aminomethyl]‐8‐substituted naphtho‐[2,1‐6]thiophene‐4‐methanols 7 and by a standard two‐step amide preparation to the N‐(3‐dimethylaminopropyl)‐8‐substituted naphtho[2,1‐6]thiophene‐4‐carboxamides 8.
Chemistry of thienopyridines. XXXIII. Synthetic routes to 5‐ and 7‐substituted thieno[3,2‐b]pyridines from the N‐oxide
Authors: Klemm L. H. , Louris John N. , Boisvert William , Higgins Clay , Muchiri Daniel R.
Published: April 2009

Thieno[3,2‐b]pyridine (1) is oxidized to N‐oxide 1a by means of m‐chloroperoxybenzoic acid (83%). Compound 1a forms adducts with hydrogen chloride and picric acid and gives ring substitution alpha or gamma to the heteronitrogen atom. Thus, 1a plus nitric and sulfuric acids produces the 7‐nitro‐N‐oxide 1m (63%), or plus phosphorus oxychloride gives a mixture of 5‐chloro and 7‐chloro (1j) derivatives of 1. Compound 1m is convertible into a variety of other derivatives of 1, viz. 7‐chloro‐N‐oxide, 1j, 7‐bromo‐N‐oxide, 7‐nitro and 7‐amino. 5‐Cyano‐1, formed from 1a, is, in turn, transformed into a methyl imidate (93%), cyclic amidines, and a 5‐tetrazolyl‐1 (91%). These results confirm the prediction that 1a, thieno[2,3‐b]pyridine‐4‐oxide and quinoline 1‐oxide should exhibit closely similar (i.e. analogous) chemical reactions.
Nitrogen bridgehead compounds. Part 51 Autoxidation of 9‐aminotetrahydro‐4H‐pyrido[1,2‐a]pyrimidin‐4‐ones. Synthesis and stereochemistry of 9‐amino‐ and 9‐hydroxy‐6,7‐dihydro‐4H‐pyrido[1,2‐a]‐pyrimidin‐4‐ones
Authors: Breining Tibor , Hermecz István , Podányi Benjamin , Sessi John
Published: April 2009

In solution the 9‐phenylaminotetrahydro‐4H‐pyrido[1,2‐a]pyrimidin‐4‐ones 1‐5 were oxidized into the 9‐aminodihydro compounds 15‐19 by atmospheric oxygen at ambient temperature. Autoxidation is most probably a free‐radical chain process, which takes place with ground‐state triplet oxygen via the radical cation of the enamine form. The 9‐aminodihydro derivatives were also prepared from 9,9‐dibromo compounds 10 and 11 and from 9‐hydroxydihydro compounds 12‐14. The 9‐hydroxydihydro derivatives, obtained from the 9‐amino compounds 16, 19 and 21 by acidic hydrolysis, showed a solvent‐dependent and R1 substituent‐dependent oxo‐enol tautomerism. The enol form was stabilized by electron‐withdrawing R1 groups and a polar solvent. However, for the 9‐aminodihydropyrido[1,2‐a]pyrimidines 15‐26 only the enamine tautomer (E) could be identified independently of the substituent and the solvent. The chemical structures of the synthesized products were studied by uv, ir, 1H‐ and 13C‐nmr spectroscopy.
Synthesis of 2‐thiobenzimidazole derivatives as potential antifilarial agents
Authors: Ram Siya , Wise Dean S. , Townsend Leroy B.
Published: April 2009

Several 5‐benzoyl‐2‐thiobenzimidazole and 2‐thiobenzimidazole aliphatic acids, esters, and N,N‐dialkyl‐carboxamides and thiocarboxamides were prepared by reacting bromo aliphatic acids, bromo aliphatic esters, and N,N‐dialkylcarbamoyl or thiocarbamoyl chlorides with 5‐benzoyl‐2‐thiobenzimidazole or 2‐thiobenzimidazole in the presence of base. 2‐Thiocarbomethoxy‐ and 2‐thiocarboethoxybenzimidazole were prepared by the reaction of 2‐thiobenzimidazole with methyl or ethyl chloroformate in the presence of base. However, the reaction of 5‐benzoyl‐2‐thiobenzimidazole with ethyl chloroformate, afforded 5‐benzoyl‐2‐ethylthiobenz‐imidazole.
Synthesis and properties of some 7‐dimethylamino‐1,4‐benzoxazin‐2‐ones
Authors: Le Bris Marie‐Thérèse
Published: April 2009

The synthesis of the 7‐dimethylamino‐1,4‐benzoxazin‐2‐ones (5), fluorescent dyes, by condensing α‐keto‐acids with 2‐amino‐5‐dimethylaminophenol is described. When the 3‐substituent is a methyl group, these compounds can be further condensed with aromatic aldehydes to provide the styryl dyes (6). These products are easily opened by hydrochloric acid in ethanolic solution to afford the corresponding benzalketoacid ethyl esters (7).
Synthèse d'analogues azotés d'esters chrysanthémiques et pyréthriques
Authors: Expert Jacques , Gelas‐Mialhe Yvonne , Vessière Roger
Published: April 2009

Les diméthyl‐3,3 vinyl‐2 éthoxycarbonyl‐1 aziridines sont préparées par action de phosphoranes, phospho‐nate ou α‐triméthylsilylcarbanion sur des acyl‐2 aziridines. Nous décrivons également la synthèse d'une diméthyl‐3,3 éthoxycarbonyl‐2N‐vinylaziridine. Ces composés constituent des analogues des esters chrysanthémiques et pyréthriques.
Reaction of 2,5‐diisopropyl‐ and 2,5‐di‐sec‐butylpyrazine 1‐oxide. Derivatives with phosphoryl chloride and acetic anhydride
Authors: Inoue Masami , Abe Reiko , Tamamura Hideo , Ohta Minoru , Asami Keiko , Kitani Hisayuki , Kamei Hideko , Nakamura Yumiko , Watanabe Tokuhiro , Ohta Akihiro
Published: April 2009

In order to examine the α‐substitution of side chains, various derivatives of 2,5‐diisopropyl‐ and 2,5‐disec‐butylpyrazine 1‐oxides were subjected to the reaction with phosphoryl chloride and acetic anhydride. Chlorination and acetoxylation were recognized to take place on the pyrazine ring in almost all cases.
Cesium fluoride assisted synthesis of macrocyclic polyethers with aromatic subunits
Authors: Czech Bronislaw P. , Czech Anna , Bartsch Richard A.
Published: April 2009

Several features of the synthesis of crown ethers with aromatic subunits by reactions of dihydroxyaromatic or bis(hydroxyaromatic) compounds with cesium fluoride and polyethylene glycol tosylates are explored. The method is utilized to prepare several new crown ethers and to synthesize known crown compounds in improved yields.
Synthèse d'azamacrocycles polysubstitués par des peptides biologiquement actifs
Authors: Kraus Jean Louis
Published: April 2009

Dans le but d'étudier le phénomène de clustérisation des récepteurs membranaires, nous rapportons la Synthèse de nouveaux dérivés tétraazacycloalkanes substitués par l'intermédiaire d'intercalateurs à des peptides (N‐formyl‐Met‐Leu‐Phe)biologiquement actifs.
Preparation and reactions of mono‐reissert compounds and analogs at the 3,4‐position of quinazoline
Authors: Kant Joydeep , Popp Frank D. , Uff Barrie C.
Published: April 2009

Quinazoline, acid chlorides, and trimethylsilyl cyanide have been converted to mono‐Reissert compounds at the 3,4‐position of the quinazoline system. Various reactions of these quinazoline Reissert compounds are reported.
Reactions of 2,3‐diamino‐4(3H)‐pyrimidinones. II
Authors: Hlavka Joseph J. , Bitha Panayota , Lin Yang‐I , Strohmeyer Timothy
Published: April 2009

The reaction of 2,3‐diamino‐4(3H)‐pyrimidinones with α,β‐diketones and orthoesters is described.
The nitration of 3,5‐ and 2,6‐diphenyl‐4‐pyrone
Authors: Katritzky Alan R. , Faid‐Allah Hassan
Published: April 2009

3,5‐Diphenyl‐4‐pyrone is nitrated in the phenyl groups under different conditions ortho and/or para to yield the 2′,2″‐di‐, the 4′,4″‐di‐, and the 2′,2″,4′,4″‐tetranitro derivatives. 2,6‐Diphenyl‐4‐pyrone undergoes meta nitration to give the 3′,3″‐dinitro derivative.
Synthèse d'analogues furannique et nitro‐2 furannique du benzo[e]pyrène
Authors: Demerseman Pierre , Trie Bernadette , Royer René , Strapélias Hélène
Published: April 2009

Le pyréno[4,5‐b]furanne et le nitro‐10 pyréno[4,5‐b]furanne sont obtenus à partir du formyl‐5 hydroxy‐4 pyrène qui est lui‐měme préparé, en six étapes, à partir du pyrène.
Conjugated azoalkenes. Part II. Synthesis of some heterocyclic azoalkenes
Authors: Attanasi Orazio , Filippone Paolino , Mei Amedeo , Serra‐Zanetti Franco
Published: April 2009

The synthesis of a new class of unknown heterocyclic conjugated azoalkene derivatives is reported.
Synthesis of 10‐(4‐methyl‐1‐piperazinyl)thieno[3,2‐b][1,5]benzothiazepines
Authors: Corral Carlos , Lasso Ana , Lissavetzky Jaime , Valdeolmillos Ana M.
Published: April 2009

A series of the title compounds has been synthesized by two alternative methods in order to study their potential neuroleptical activity and to compare it with the pharmacological data already obtained for compounds of other isomeric or related series.
Synthesis of 10‐(4‐methyl‐1‐piperazinyl)thieno[3,2‐b][1,5]benzoxazepines
Authors: Corral Carlos , Lissavetzky Jaime , Valdeolmillos Ana M.
Published: April 2009

A series of the title compounds has been synthesized starting from methyl 3‐hydroxythiophene‐2‐carboxylate. Its condensation with 2,4‐dinitrochlorobenzene provides through compound 4e a way to introduce 7‐substituents by means of diazonium salts reactions.
Reaction of 5‐(3,4‐dimethoxyphenyl)pyrazine‐2,3‐dicarbonitrile with alcohol in the presence of base
Authors: Tsuzuki Koichi , Tada Masaru
Published: April 2009

5‐(3,4‐Dimethoxyphenyl)pyrazine‐2,3‐dicarbonitrile reacts with methanol to give addition products, 3‐methoxyiminopyrazine‐2‐carbonitrile and 2‐methoxyiminopyrazine‐3‐carbonitrile derivatives, and/or substitution products, 3‐methoxypyrazine‐2‐carbonitrile and 2‐methoxypyrazine‐3‐carbonitrile derivatives. The selectivity between the addition and substitution depends on solvent polarity, base, and reaction time. The experimental results are accounted for by the equilibrium between the starting dinitrile and the addition products, methoxyiminopyrazine.
Nitrogen bridgehead compounds. Part 55 Synthesis of substituted 7,8‐dihydro‐5H,13H‐indolo[2′,3′:3,4]pyrido[2,1‐b]quinazolin‐5‐ones
Authors: Hermecz István , Pod Benjaminányi , Mészáros Zoltán , Szász György , Kökösi József
Published: April 2009

Fischer indolization of 6‐arylhydrazono‐6,7,8,9‐tetahydro‐11H‐pyrido[2,1‐b]quinazolin‐11‐ones 1 afforded substituted 7,8‐dihydro‐5H,13H‐indolo[2′,3′:3,4]pyrido[2,1‐b]quinazolin‐5‐ones 3‐12 in high yields.
Oxidation of aldehyde semicarbazones with lead dioxide: Application to the syntheses of 2‐amino‐1,3,4‐oxadiazoles and 2,4‐dihydro‐1,2,4‐triazol‐3‐ones
Authors: Nguyen Thu‐Huong , Milcent René , Barbier Geo
Published: April 2009

The oxidation of aldehyde semicarbazones with lead dioxide in acid media was effected. The 4,4‐disubstituted semicarbazones of aromatic aldehydes afford 2‐amino‐1,3,4‐oxadiazole derivatives. The 2,4‐disubstituted semicarbazones give 2,4‐dihydro‐1,2,4‐triazol‐3‐ones, often in higher yields than the known methods. The mechanisms for the formation of these compounds are proposed.
A study of tautomerism in diazonium coupling products of 4‐hydroxycoumarin
Authors: Shawali Ahmad S. , Harb Nagwa M. S. , Badahdah Khadiga O.
Published: April 2009

The spectra (1H nmr, ir and uv) of a series of 3‐arylazo‐4‐hydroxycoumarins 1a‐m indicate that such compounds exist predominantly in the keto hydrazone form 1A both in solid state and in solution. The acid dissociation constants of the series studied were determined spectrophotometrically in 80 vol% ethanol‐water mixture at 27° and ionic strength of 0.1. The results of the correlations of these constants by Hammett and Yukawa‐Tsuno equations exclude the presence of the hydroxyazo form 1B in equilibrium with 1A in agreement with the spectral data. Also, the HMO method has been used to study tautomerism in such compounds. The results are also in full agreement with both the spectral and linear free energy correlations, the hydrazone form 1A being the most stable. It is further shown that both the intermolecular and intramolecular hydrogen bonding favor the hydrazone tautomer.
Derivate von 4,5‐dihydroxypyridonen durch ringerweiterung
Authors: Stachel Hans‐Dietrich , Wiesend Bruno , Kreiner Christine
Published: April 2009

Die epimeren Bromhydrine 13/14 sowie deren Ether 5/6 lagern in Gegenwart von Silberionen zu den 5‐Hydroxypyridonen 15 bzw. deren Ketalen 9 um. Bei den Bromhydrinethern 5/6a und b tritt diese Umsetzung auch mit Methylat ein. Unter diesen Reaktionsbedingungen verläuft die Ringerweiterung vermutlich über bicyclische Aziridine, von denen 7 isoliert werden konnte. Die N‐methylierten Verbindungen 5c/6c, die nicht in gleicher Weise reagieren können, bilden mit Methylat das 6‐Methoxypyridon 12.
Synthesis of 4‐alkyl‐3‐pyridinols from 3‐benzyloxypyridine
Authors: Comins Daniel L. , Stroud Eric D.
Published: April 2009

The addition of Grignard reagents to the 1‐phenoxycarbonyl salt of 3‐benzyloxypyridine and a catalytic amount of cuprous iodide afforded 4‐alkyl‐3‐benzyloxy‐1‐phenoxycarbonyl‐1,4‐dihydropyridines in good yield. The crude dihydropyridines were aromatized with o‐chloranil to give 4‐alkyl‐3‐benzyloxypyridines, which were debenzylated with hydrogen and 10% palladium on carbon to provide 4‐alkyl‐3‐pyridinols.
Chemoselective reductions of 2‐acyl‐1H‐indole‐3‐carboxaldehydes
Authors: Djurić Stevan W. , Herbert Richard B. , Holliman Frederick G.
Published: April 2009

A novel procedure for the chemoselective reduction of 2‐acyl‐1H‐indole‐3‐carboxaldehydes has been developed. Low temperature lithium triethylborohydride reduction affords the indol‐2‐yl carbinol whilst sodium cyanoborohydride reduction in acetic acid affords the 3‐hydroxymethyl analogs. Both processes are high yield, and provide access to intermediates of potential utility for indole alkaloid synthesis.
About the synthesis of [1,2]diazepinoindole derivatives from ethyl 2‐(1‐methylindole)acetate, 2‐indole and 3‐indoleacetohydrazones
Authors: Monge A. , Palop J. A. , Goñí T. , Martínez A. , Fernández‐Alvarez E.
Published: April 2009

The Vilsmeier‐Haack reaction with ethyl 2‐(1‐methylindole)acetate and N,N‐Dimethylamides/phosphorus oxychloride gave (65–85%) of ethyl 2‐(3‐acyl‐1‐methylindole)acetates 2, which when boiled with hydrazine yielded about 90% of 4,5‐dihydro‐6‐methyl‐4‐oxo‐3H[1,2]diazepino[5,6‐b]indoles 3. The attempted cyclization of 2‐(1‐methylindole)acetohydrazones 6 with acyl (acetyl and benzoyl) chlorides/triethylamine, to [1,2]diazepino[5,6‐b]indole derivatives was fruitless and the bis(acyl)hydrazones 9 were obtained. Several transformations of 9 are reported. Similarly, the attempted cyclization of 3‐indoleacetohydrazones 14 with acetyl chloride/triethylamine to [1,2]diazepino[4,5‐b]indole derivatives was also fruitless and the bis(acyl)hydrazones 16 were again obtained.
Long range optimized two‐dimensional proton‐carbon chemical shift correlation. Application in the total assignment of the 1H‐ and 13C‐NMR spectra of 9‐methylphenanthro[4,3‐a]dibenzothiophene
Authors: Quast Michael J. , Ezell† Edward L. , Martin Gary E. , Lee Milton L. , Tedjamulia Marvin L. , Stuart John G. , Castle Raymond N.
Published: April 2009

The utilization of the long range optimized proton‐carbon chemical shift correlation experiment in the total assignment of the proton and carbon nmr spectra of 9‐methylphenanthro[4,3‐a]dibenzothiophene is described. The experiment was employed in concert with conventional proton‐carbon chemical shift correlation, heteronuclear relayed coherence transfer and broad band homonuclearly decoupled proton‐carbon chemical shift correlation experiments. The experiments in combination offer a useful alternative to the 13C‐13C double quantum coherence experiments, providing significantly better sensitivity and nearly the same capabilities.
Formation of 3‐phenylhydrazono‐3‐aroylpropionamides from the reaction of 5‐aroyl‐3(2H)‐isothiazolones with phenylhydrazine
Authors: Tsolomitis A. , Sandris C.
Published: April 2009

Reaction of 2‐substituted‐5‐aroyl‐3(2H)‐isothiazolones 1 with phenylhydrazine in refluxing ethanol was found to give sulfur‐free products, which were characterized as 3‐phenylhydrazono‐3‐aroyl‐N‐substituted‐pro‐pionamides 4. Acid hydrolysis of the 3‐benzoyl compounds 4 was shown to yield 1‐phenyl‐3‐benzoyl‐2‐pyrazolin‐5‐one (7), whose structure was confirmed by an independent synthesis starting with the chloride of 1‐phenyl‐5‐methoxypyrazole‐3‐carboxylic acid (10).
Facile dibenzoylation of picoline
Authors: Suzuki Toshinobu , Mitsuhashi Keiryo
Published: April 2009

In the presence of triethylamine, 2‐ and 4‐picolines reacted with an excess of benzoyl chloride in refluxing acetonitrile to give the corresponding 1‐benzoyl‐phenacylidenedihydropyridines. The difference in reactivity between 2‐ and 4‐picoline toward such a dibenzoylation was studied from the conversion rates under various conditions with hplc. It was also clarified that the dibenzoylation proceeded via the intermediate phenacylpyridine and a plausible reaction scheme has been proposed, considering the significant role of triethylamine.
Mechanism of the condensation reaction between 1‐aryl‐ and heteroaryl‐1,4‐dihydro‐3(2H)‐isoquinolinones and aldehydes
Authors: Hazai László , Deák Gyula , Tamás József , Doleschall Gábor , Tóth Gabor
Published: April 2009

4‐Benzylidene‐1‐phenyl‐1,4‐dihydro‐3(2H)‐isoquinolinone, the intermediary product of the carbonyl condensation reaction between 1‐phenyl‐1,4‐dihydro‐3(2H)‐isoquinolinone and benzaldehyde, rearranges in the presence of an equivalent quantity of sodium hydride into 4‐benzyl‐1‐phenyl‐3(2H)‐isoquinolinone. As the possibility of the migration of the hydrogen at C‐1 in the form of a proton or a hydrogen atom (radical reaction) was excluded, the mechanism of the rearrangement could be depicted as an intermolecular hydride anion migration. In case of the 1‐(4‐pyridyl)‐ and 1‐(3‐pyridyl)‐1,4‐dihydro‐3(2H)‐isoquinolinones, however, the rearrangement can be carried out also in polyphosphoric acid and in this case a proton loss‐proton gain mechanism was proved.
Pyridazino[3,4‐b]quinoxalines and their reduced derivatives. Preparation and structure
Authors: Armand Joseph , Armand Yvette , Boulares Line , Bellec Christian , Pinson Jean
Published: April 2009

The reaction of o‐phenylenediamine with a β‐ketoacid, leads in most cases to quinoxalinones. Their structure has been determined as well as that of their corresponding hydrazones. The reaction of hydrazine with these quinoxalinones gives dihydropyridazino[3,4‐b]quinoxalines, the structure of which has been ascertained. It has been shown that among the six possible formulas, the only 1,2‐dihydro structure fits with the spectroscopic data. On the contrary, N‐substituted o‐phenylenediamines lead to 2,10‐dihydro derivatives. The electrochemical behavior of the 2,10‐dihydro‐10‐methyl‐3‐phenylpyridazino[3,4‐b]quinoxaline has been investigated. It has also been shown that the 3,4,6‐trichloropyridazine reacts with o‐phenylenediamines to give 5,10‐dihydropyridazino[3,4‐b]quinoxalines. These compounds can be oxidized to give the new heterocycle pyridazino[3,4‐b]quinoxaline.
Chemistry of quinazolines: Reinvestigation of the action of hydrazine on thioxo derivatives
Authors: Badawy Mohamed A. , Abdel‐Hady Sayed A. L. , Ibrahim Yehia A. , Kadry Azza M.
Published: April 2009

The action of hydrazine on 2‐mercapto and 2‐alkylmercaptoquinazolin‐4‐ones is reinvestigated. The structure of the isolated products have been revised.
Synthesis of 3,3′‐(1,6‐hexanediyl)bis‐pyrimidine derivatives and 3,4‐dithia[6.6](1.3)pyrimidinophane
Authors: Kinoshita Toshio , Odawara Shirou , Fukumura Keiko , Furukawa Sunao
Published: April 2009

Several 3,3′‐(1,6‐hexanediyl)bis[6‐methyl‐2,4(1H,3H)‐pyrimidinedione] derivatives (4a, 4b, and 4c) were synthesized from 1,6‐(hexanediyl)bis[6‐methyl‐2H‐1,3‐oxazine‐2,4(3H)‐dione] (3). Compound 4c was converted to 6, which reacted with thiourea giving thiuronium salt 7. 3,3′‐(1,6‐Hexanediyl)bis [1‐(2‐mercaptoethyl)‐6‐methyl‐2,4(1H,3H)‐pyrimidinedione] (9) was obtained by the hydrolysis of 7, and then 9 was oxidized to 12,22‐dimethyl‐3,4‐dithia[6.6] (1.3)‐1,2,3,4‐tetrahydro‐2,4‐dioxopyrimidinophane (10).
3,4‐Dihydro‐2‐phenyl‐2H‐pyrano[2,3‐b]pyridines. Novel aza analogs of flavans
Authors: Bargar T. M. , Wilson T. , Daniel J. K.
Published: April 2009

Complementary approaches to the synthesis of the title compounds 1 are described. Metallation of 3,5‐di‐bromo‐2‐methoxypyridine (5b) by bromine/lithium exchange gave selectively the 3‐lithio intermediate 6 which was trapped with substituted cinnamaldehydes 7, providing allylic alcohols 8 in good yields. Methyl ether cleavage and concomitant cyclization occurred on exposure to concentrated hydrobromic acid in hot acetic acid. The resulting 2‐phenyl‐2H‐pyrano[2,3‐b]pyridines were hydrogenated over Raney nickel to the title compounds which had antiviral activity. Alternatively, 1 were synthesized by Heck reaction of appropriately substituted 3‐halo‐2‐methoxypyridines (5 or 24) with vinyl carbinol 15 to furnish ketones 16 or 26 which, upon reduction of the carbonyl group, were cyclized directly to 1.
Antimicrobial activity of 3‐(substituted methyl)‐2‐phenyl‐4H‐l‐benzothiopyran‐4‐ones
Authors: Nakazumi Hiroyuki , Ueyama Tamio , Kitao Teijiro
Published: April 2009

A series of 3‐(substituted Methyl)‐2‐phenyl‐4H‐l‐benzothiopyran‐4‐ones (thioflavones) and thioflavone 1,1‐dioxides was prepared to test for antimicrobial activity and for antitumor activity. It was shown that an introduction of a substituted methyl group in the 3‐position of thioflavone resulted in significant antimicrobial activity against Trichophytons. 3‐(Acetoxymethyl)thioflavone shows the most antimicrobial potency in vitro against Trichophyton mentagrophytes. Most of the thioflavone 1,1‐dioxides showed antimicrobial activity against fungi. Five of the 40 related compounds demonstrated weak antitumor activity against P‐388 lymphocytic leukemia.
Heterocycles of biological importance. Part 2. Novel synthesis and pharmacological evaluation of 5‐amino‐3‐alkyl‐1‐(2‐pyridyl)pyrazoles and 5‐amino‐3‐phenyl‐1‐(2‐pyridyl)pyrazole from allenic or acetylenic nitriles and 2‐hydrazinopyridine
Authors: Fomum Z. Tanee , Ifeadike P. Ngozi
Published: April 2009

2‐Hydrazinopyridine reacts with allenic and acetylenic nitriles to give 5‐amino‐3‐alkyl‐1‐(2‐pyridyl)pyrazoles 6 in excellent yields. One of these compounds, 6e has been shown to possess anticonvulsant and anti‐electroshock properties. Phenyl propynenitrile also reacts with hydrazinopyridine to give 5‐amino‐3‐phenyl‐1‐(2‐pyridyl)pyrazole (11) in quantitative yield.
Syntheses and reactions of 2‐halo‐5‐thiazolecarboxylates
Authors: Lee Len F. , Schleppnik Francis M. , Howe Robert K.
Published: April 2009

A variety of 2‐halo‐5‐thiazolecarboxylates was prepared from substituted‐3‐aminoacrylates and 3‐ketoes‐ters. Selective reduction of 2‐chloro‐5‐thiazolecarboxylates 4a, 4i and 4j with sodium borohydride in ethanol provided the corresponding 2‐halo‐5‐thiazolemethanols 27‐29. Nucleophilic displacements on [2‐chloro‐4‐(trifluoromethyl)‐5‐thiazolyl]methyl methanesulfonate (32c) occurred selectively at the 5‐substituent to provide 2‐chloro‐4‐(trifluoromethyl)‐5‐(heteroatom‐substituted‐methyl)thiazoles 32d‐f.
The synthesis and structure of 5‐hydroxy‐2‐methyl‐2‐(2‐pyridinyl)hexahydro‐1,3‐pyrimidine
Authors: Fenton David E. , Moody Richard , Casellato Umberto , Vigato P. A. , Graziani Rodolfo
Published: April 2009

The synthesis and the x‐ray structure of 5‐hydroxy‐2‐methyl‐(2‐pyridinyl)hexahydro‐1,3‐pyrimidine are reported. The compound was prepared by reaction of 2‐acetylpyridine and 1,3‐diamino‐2‐hydroxypropane in a 2:1 molar ratio. The colourless crystals are monoclinic, space group P21/c with cell parameters, a = 10.385(5), b = 11.171(5), c = 17.415(6)Å, β = 93.05(37)° for Z = 8. The asymmetric unit of the structure is composed of two independent molecules of the compound which are in the chair form and adopt the same conformation with equatorial ‐OH and ‐CH3 groups and axial pyridine substituents. The packing of the molecule seems to be controlled by two independent hydrogen‐bonding sequences.
Basicity of the nitrogen atom and of the carbonyl function of methyl isonicotinate and 4‐acetylpyridine. An infrared study of the interaction with proton donors
Authors: Kasende O. , Vanderheyden E. , Zeegers‐Huyskens Th.
Published: April 2009

The hydrogen bonded complexes between methyl isonicotinate and 4‐acetylpyridine and phenol derivatives acting as proton donors have been investigated by ir spectroscopy. The thermodynamic parameters (K, — ΔH°, — ΔS°) have been determined. The ir data show that the hydrogen bond interaction occurs at the carbonyl function and at the nitrogen atom of the ring. When the acidity of the proton donor increases, N‐complexation is favoured over carbonyl complexation and with the stronger acid hydrochloric acid, only N‐protonated species are observed. The data are compared with those obtained for closely related pyridine derivatives, bearing a X‐C=O substituent and it is shown that the proportion of OH···N and OH···O=C species is related to the basicity of the nitrogen atom of the heterocyclic ring and to inductive and mesomeric effects depending on the nature of X.
Synthesis of heterocyclic compounds XLIX. An unexpected synthesis of isoxazolamines
Authors: Ciller J. A. , Seoane C. , Soto J. L.
Published: April 2009

Reaction of 3‐aryl‐1‐phenyl‐2‐nitropropenones 1 with potassium cyanide leads to 4‐aryl‐3‐benzoyl‐5‐isoxazo‐lamines 5 in a one‐step process involving the formal reduction of the nitro group followed by nucleophilic attack at the cyano group. Treatment of the isoxazolamine with an aromatic aldehyde yields the corresponding N‐arylideneisoxazolamine.
Annulated 1,2,3‐triazoles. 3. Synthesis of 1,2,3‐triazolo[4,5‐b][1,5]benzoxazepin‐10(9H)‐ones and 10‐(4‐substituted‐1‐piperazinyl)‐1,2,3‐triazolo[4,5‐b][1,5]benzoxazepines
Authors: Nielsen Flemming E. , Pedersen Erik B.
Published: April 2009

10‐(4‐Substituted‐1‐piperazinyl)‐1,2,3‐triazolo[4,5‐b][1,5]benzoxazepines 11 were prepared in a three‐step synthesis starting from easily available 5‐chloro‐1,2,3‐triazole‐4‐carbonyl chlorides 7 by titanium tetrachloride catalyzed condensation of N‐(substituted)piperazines with 1,2,3‐triazolo[4,5‐b][1,5]benzoxazepin‐10(9H)‐ones 10 formed by ring closure of the intermediate amides 9. Although lactams 10 were obtained as the sole product of the cyclisation at 80°, the unexpected by‐products 13 and 14 were formed in addition to 10c at 150° from 9c. The 4‐methoxybenzyl group in 11j was easily removed by solvolyses in TFA. Compounds 11d‐f and 11i were tested for psychotropic activity.
Nucleosides. 130. Synthesis of 2′‐Deoxy‐2′‐substituted‐ and 5′‐Deoxy‐5′‐substituted‐ψ‐uridine Derivatives. Crystalline and Molecular Structure of 2′‐Chloro‐2′‐deoxy‐1,3‐dimethyl‐ψ‐uridine. Studies Directed Toward the Synthesis of 2′‐Deoxy‐2′‐substituted‐arabino‐Nucleosides. 1
Authors: Pankiewicz Krzysztof W. , Watanabe Kyoichi A. , Takayanagi Hiroaki , Itoh Tsueno , Ogura Haruo
Published: April 2009

A method was developed to prepare 5′‐deoxy‐5′‐substituted‐ψ‐uridine derivatives 4 from 3′,5′‐O‐(1, 1, 3, 3‐tetraisopropyldisiloxanyl)‐1,3‐dimethyl‐ψ‐uridine 1 via a silyl rearrangement reaction. Nucleophilic displacement of the mesyloxy function of 2′‐O‐mesyl‐1,3‐dimethyl‐ψ‐uridine 7 afforded products with the 2′‐substituent in the “down” ribo configuration 8. X‐Ray crystallographic analysis of the 2′‐chloro derivative 8a firmly established the molecular structure of 8 and provided evidence for neighboring group participation of the 4‐carbonyl function of 7 during the nucleophilic reactions.

Treatment of 1,3‐dimethyl‐ψ‐uridine 11 with α‐acetoxyisobutyryl chloride afforded a mixture from which two 2′‐chloro‐2′‐deoxy‐C‐nucleosides were obtained. The major product (33% yield) was identical with 8. The minor product (7% yield) was consequently assigned the arabino nucleoside 14. This is the first direct introduction of a 2′‐substituent in the “up” configuration in a preformed pyrimidine nucleoside.
Synthesis and conversions of 3‐(4‐amino‐5‐methyl‐4H‐1,2,4‐triazol‐3‐ylmethylene)‐2‐oxo‐1,2,3,4‐tetrahydroquinoxaline
Authors: Kurasawa Yoshihisa , Okamoto Yoshihisa , Takada Atsushi
Published: April 2009

The reaction of the hydrazone 3a with hydrazine hydrate in DBU/ethanol conveniently gave 3‐(4‐amino‐5‐methyl‐4H‐1,2,4‐triazol‐3‐ylmethylene)‐2‐oxo‐1,2,3,4‐tetrahydroquinoxaline 6. The reactions of 6 with an equimolar and 2‐fold molar amount of nitrous acid afforded 3‐(α‐hydroxyimino‐4‐amino‐5‐methyl‐4H‐1,2,4‐triazol‐3‐ylmethyl)‐2‐oxo‐1,2‐dihydroquinoxaline 9 and 3‐(α‐hydroxyimino‐5‐methyl‐2H‐1,2,4‐triazol‐3‐ylmethyl)‐2‐oxo‐1,2‐dihydroquinoxaline 10, respectively, which were converted into the 3‐heteroarylisoxazolo[4,5‐b]quin‐oxalines 13a,b and 11, respectively. Compound 9 was also cyclized into the 8‐quinoxalinyl‐1,2,4‐triazolo‐[3,4‐f][1,2,4]triazines 14a,b.
Synthesis and degradation of 3‐amino‐3‐(2‐substituted benzimidazol‐1‐yl)‐2‐(2‐phenyl‐1,1‐diazanediylmethyl)‐2‐propenenitrile: Hydroxyl group‐promoted CN bond fission
Authors: Okamoto Yoshihisa , Kurasawa Yoshihisa , Takada Atsushi , Takagi Kaname
Published: April 2009

The reaction of 3‐amino‐3‐(o‐aminoanilino)‐2‐cyano‐2‐propenal phenylhydrazone (2) with orthoesters gave the title compound (3), which was readily converted to 2‐substituted benzimidazole (4) and 5‐amino‐4‐cyano‐1‐phenylpyrazole (5) when heated in 1‐butanol. The degradation mechanisms were proposed.
2‐Amino‐ and 2‐guanidino‐4‐thiazolylpyrimidines
Authors: Lipinski Christopher A. , Craig Rebecca H. , Wright Roger B.
Published: April 2009

The synthesis of the four possible 2‐amino‐ and 2‐guanidino‐ 4‐(2‐amino‐ and 2‐guanidinothiazolyl)pyrimi‐dines is described and pKa. values are calculated. Guanidinopyrimidines are more basic than guanidinothiazoles. However, the reverse is true of the corresponding amino heterocycles; the amino thiazole is more basic than the amino pyrimidine.
New synthesis of α‐nitroalkyl‐ and α‐nitroaralkylcarboxylic esters from α‐nitroalkyl‐ and α‐nitroaralkyl‐2‐oxazolines
Authors: Feuer Henry , Bevinakatti Hanamanthsa S. , Luo Xuan‐Gan
Published: April 2009

2‐Nitroalkyl‐ and 2‐nitroaralkyl‐2‐oxazolines are readily converted, in one step, to α‐nitroalkyl‐ and α‐nitroaralkylcarboxylic esters on treatment with the appropriate alcohol and trifluoroacetic acid (TFA). The initial products of the ring cleavage are the TFA salts of the ammonioalkyl esters of α‐nitroalkyl‐ and α‐nitroaralkylcarboxylic acids. These salts undergo facile transesterification to the α‐nitrocarboxylic esters on refluxing with the appropriate alcohol.