bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and spectroscopic properties for six 7,16‐dibenzoylated tetraaza[14]annulene nickel(II) complexes
Authors: Sakata Kazunori , Koyanagi Ken , Hashimoto Mamoru
Published: March 2009

The condensation reaction between tetraaza[14]annulene nickel(II) complex and a series of para‐substituted benzoyl chlorides gave the corresponding 7,16‐dibenzoylated products in 53–98% yields. The mass spectra exhibit molecular ion peaks ascribed to the 7,16‐dibenzoylated products. The intense ir band due to the CO stretching mode in these nickel(II) complexes is present in the 1650–1658 cm−1 range upon the benzoylation. Even though the ligand moiety of these six complexes is changed by benzoylation, the electronic spectra hardly vary. These nickel(II) complexes assume roughly the square‐planar coordinations as judged by the ligand‐field transition bands. The olefinic proton peaks at the 7‐ and 16‐positions vanish on benzoylation in the proton nmr spectra and the proton signals of the para‐substituted benzoyl groups are observed in the 2.4–8.4 ppm region. The results of the carbon‐13 nmr spectra are compatible with those for the proton nmr spectra.
The synthesis of three indolizine derivatives of interest as non‐isomerizable analogues of tamoxifen
Authors: Mehta Lina K. , Parrick John
Published: March 2009

Three novel derivatives of indolizine21, 23, and25have been prepared as analogues of the anti‐cancer agent tamoxifen1. The compounds showed low relative binding affinity at the estrogen receptor.
Pyridine‐substituted hydroxythiophenes. IV. Preparation of 3‐ and 4‐(2‐, 3‐ and 4‐pyridyl)‐2‐hydroxythiophenes
Authors: Zhang Yihua , Hörnfeldt Anna‐Britta , Gronowitz Salo
Published: March 2009

3‐(2‐, 3‐ and 4‐Pyridyl)‐2‐methoxythiophenes have been prepared in good yields through the Pd(0)‐cat‐alyzed coupling of the three isomeric bromopyridines with 3‐trimethylstannyl‐2‐methoxythiophene. This compound was prepared through halogen‐metal exchange of 3‐bromo‐2‐methoxythiophene followed by stannylation. 3‐Bromo‐2‐methoxythiophene was prepared by dibromination and α‐debromination of 2‐methoxythiophen. Most attempts to demethylate 2‐methoxy‐3‐pyridylthiophenes using a large variety of reagents failed, probably due to the instability and high reactivity of the desired 3‐pyridyl‐2‐hydroxythiophene systems. Only 2‐methoxy‐3‐(3‐pyridyl)thiophene reacted with boron tribromide to give 3‐(3‐pyridyl)‐3‐thiolene‐2‐one, which only was stable in ether solution at −20°. The attempted demethylation of 2‐methoxy‐3‐(2‐pyridyl)thiophene with trimethylsilane chloride/sodium iodide in refluxing acetonitrile led to a dimer. Demethylation of the 2‐methoxy‐3‐pyridylthiophenes with dibenzyl diselenide and sodium borohydride gave 3‐pyridylthiophan‐2‐ones.

A number of other routes to prepare 3‐pyridyl‐2‐hydroxythiophenes were also explored, but none of them gave the desired compounds. On the other hand, the 4‐(2‐, 3‐, and 4‐pyridyl)‐2‐hydroxythiophene systems could easily be prepared by hydrogen peroxide oxidation of the corresponding 4‐pyridyl‐2‐thiopheneboronic esters, which were obtained from 2‐bromo‐4‐pyridylthiophenes by halogen‐metal exchange followed by reaction with ethyl borate. The 2‐bromo‐4‐pyridylthiophenes were prepared by dibromination of the known 3‐pyridylthiophenes to the 2,5‐dibromo derivatives, and removal of the 2‐bromine by halogen‐metal exchange at −100°, followed by hydrolysis. The 1H nmr and ir spectroscopic investigations show that these quite stable 2‐hydroxythiophene systems exist exclusively in the 4‐pyridyl‐3‐thiolen‐2‐one forms.
Convergent syntheses of luteoreticulin and didemethylluteoreticulin
Authors: Lyga John W.
Published: March 2009

Convergent syntheses of luteoreticulin (1a) and didemethylluteoreticulin (1c) are described which are ammenable to structural variation in both the pyran and phenyl rings.
Synthesis and properties of two new N‐alkyl substituted phthalocyanines
Authors: Fernández Daniel A. , Dicelio Lelia E. , Awruch Josefina
Published: March 2009

The synthesis and properties of tetrakis(1,1‐dimethyl‐2‐phthalimido)ethylphthalocyaninato zinc(II) (6) and tetrakis(1,1‐dimethyl‐2‐amino)ethylphthalocyaninato zinc(II) (7) are described. N‐Alkyl substituted phthalonitrile 5 was converted to phthalocyanine 6. which was deprotected to afford the free amino phthalocyanine 7.
Synthesis and reactions of dinitrated amino and diaminopyridines
Authors: Ritter H. , Licht H. H.
Published: March 2009

Nitration of amino‐ and diaminopyridines and ‐picolines led, in unexpected one‐step reactions, to dinitrated derivatives. Dinitropicolines gave styrylpyridines, and 2‐amino‐6‐hydroxy‐3,5‐dinitropyridine was transformed by the thermolysis of its azido derivative into 5‐amino‐6‐nitro[1,2,5]oxadiazolo[3,4‐b]pyridine. Using 1H and 13C nmr spectroscopy, azido‐tetrazole tautomerism of 2‐amino‐6‐azido‐3,5‐dinitropyridine and intramolecular hydrogen bonding at 20° for several 2‐amino‐3,5‐dinitro‐6‐R‐pyridines have been proved.
Enolethers. XXI. Synthesis of 5,5′‐disubstituted 4,4′‐bipyrimidines
Authors: Effenberger Franz , Barthelmess Ingrid
Published: March 2009

1,6‐Dialkoxy‐3,4‐diones 3 are easily accessible by acylation of enol ethers 1 with oxalyl chloride and subsequent elimination of hydrogen chloride using triethylamine. The open‐chain 2,5‐dimethyl derivative 3b is converted with amidines 4a‐c and S‐methylisothiourea (4d), respectively, to give 2,2′‐disubstituted 5,5′‐dimethyl‐4,4′‐bipyrimidines 5a‐d. The dihydrofuran and dihydropyran derivatives 3c and 3d, however, react with benzamidine (4c) in dimethylformamide only in the presence of calcium hydride as condensation agent yielding 5,5′‐bis(2‐hydroxyethyl)‐ and 5,5′‐bis(3‐hydroxypropyl)‐2,2′‐diphenyl‐4,4′‐bipyrimidine 6a and b.
Synthesis of 9H‐pyrrolo[2,1‐b][1,3,6]benzothiadiazocin‐10(11H)‐one 4,4‐dioxide, a potential anti‐HIV‐1 agent
Authors: Silvestri Romano , Pagnozzi Eugenia , Artico Marino , Stefancich Giorgio , Massa Silvio , La Colla Paolo
Published: March 2009

Starting from 2‐(2‐aminophenylthio)‐1‐ethoxycarbonylmethyl‐1H‐pyrrole a four‐step synthesis of 9H‐pyrrolo[2,1‐b][1,3,6]benzothiadiazocin‐10(11H)‐one 4,4‐dioxide, a new heterocycle related to anti‐HIV‐1 tricyclic non‐nucleoside agents, is described.
An effective synthesis of fused cyclic thiopyrans and pyrans by molybdenum(VI) sulfide catalyzed reduction of the corresponding thiopyranones and pyranones
Authors: Takido Toshio , Itabashi Kunio , Takagi Yuzuru
Published: March 2009

The synthesis of fused cyclic dihydrothiopyrans 2a‐c from dihydrothiopyranones 1a‐c and thiopyrans 2d‐f from thiopyranones 1d‐f by catalytic reduction over molybdenum(VI) sulfide (MoS3) has been studied. The hydrogenolysis of the carbonyl group of 1a‐f over MoS3 catalyst proceeded selectively to give the corresponding 2a‐f in high yields. Neither alcohols nor olefins were not detected in the products. The method was also applied successfully to the synthesis of dihydropyran 2h and pyran 2g from dihydro‐pyranone 1h and pyranone 1g.
Unambiguously confirmed structure of 2‐phenacylidene‐1,2‐dihydro‐4H‐pyrido[2,3‐b]pyrazin‐3‐one and 3‐phenacylidene‐3,4‐dihydro‐1H‐pyrido[2,3‐b]pyrazin‐2‐one
Authors: Seki Taketsugu , Sakata Hisanori , Iwanami Yasuo
Published: March 2009

To determine the structures of two isomeric products, 2‐phenacylidene‐1,2‐dihydro‐4H‐pyrido[2,3‐b]pyrazin‐3‐one (2) and 3‐phenacylidene‐3,4‐dihydro‐1H‐pyrido[2,3‐b]pyrazin‐2‐one (3) obtained by condensation of 2,3‐diaminopyridine (1) with ethyl benzoylpyruvate [1–3], these compounds were hydrolyzed to give 2‐methyl‐4H‐pyrido[2,3‐b]pyrazin‐3‐one (4) and 3‐methyl‐1H‐pyrido[2,3‐b]pyrazin‐2‐one (5), respectively [4,5]. Both hydrolysates 4 and 5 were hydrogenated to afford 2‐methyl‐1,2‐dihydro‐4H‐pyrido[2,3‐b]pyrazin‐3‐one (6) and 3‐methyl‐3,4‐dihydro‐1H‐pyrido[2,3‐b]pyrazin‐2‐one (7). The latter compound was identical with an unequivocally synthesized compound providing proof for the structures of all these compounds.
First synthesis of (±)‐harzianopyridone by metalation of polysubstituted O‐pyridylcarbamates
Authors: Tréecourt Françcois , Mallet Marc , Mongin Olivier , Quéguiner Guy
Published: March 2009

The first synthesis of (±)‐harzianopyridone, an antifungal metabolite of Trichoderma harzianum, has been achieved by metalation of 6‐substituted‐2,3‐dimethoxy‐4‐pyridyl‐N,N‐diisopropylcarbamates. Moreover, the chosen strategy allowed the preparation of harzianopyridone analogs, by varying the groups at C‐4, C‐5 and C‐6 on the pyridine ring.
Acetylenic amides. 3. The synthesis of 5‐methylene‐2,4‐imidazolidinediones from 2‐propynamides and isocyanates
Authors: Coppola Gary M. , Damon Robert E.
Published: March 2009

2‐Propynamides react with aryl isocyanates in the presence of triethylamine to give 5‐methylene‐2,4‐imidazolidinediones 5 in good yields. If the propynamide contains a terminal trimethylsilyl group, Z‐trimethylsilylidenehydantoin (7) is produced.
Synthesis of 6,7,8,9‐tetrahydro‐N,N‐di‐n‐propyl‐1H‐benz[g] indol‐7‐amine, a potential dopamine receptor agonist
Authors: Demopoulos Vassilis J. , Gavalas Antonis , Rekatas George , Tani Ekaterini
Published: March 2009

In this work, the synthesis of 6,7,8,9‐tetrahydro‐N,N‐di ‐n‐propyl‐1H‐benz[g]indol‐7‐amine (1) is described. This compound was designed as an indole bioisostere to the known dopamine receptor agonist 5‐OH‐aminotetraline 2. The key step of the synthesis was a Mukaiyama type aldol condensation between the dimethyl acetal of 1‐(p‐toluenesulfonyl)pyrrole‐3‐acetaldehyde (4) and 4‐di‐n‐propylamino‐1‐trimethylsilyloxycyclohexene (8) followed by cycloaromatization to afford 1‐p‐toluenesulfonyl‐6,7,8,9‐tetrahydro‐N,N‐di‐n‐ propyl‐1H‐benz[g]indol‐7‐amine (10). Scission of the sulfonamide bond in 10 gave the target compound 1. A byproduct which was isolated was assigned to the structure of 1‐(p‐toluenesul‐fonyl)‐6‐[3‐[1‐(p‐toluenesulfonyl)]pyrrolyl]indole (11). This compound was also synthesized in good yield by an acid catalyzed dimerization of the dimethyl acetal of 1‐(p‐toluenesulfonyl)pyrrole‐3‐acetaldehyde (4). Preliminary screening of 1 indicated that it possesses central dopamine receptor agonist properties.
Synthesis and properties of 5‐(p‐carbomethoxyphenyl)‐ 15‐(p‐dimethylaminophenyl)porphyrin
Authors: Zindel Jürgen , Lightner David A.
Published: March 2009

An unsymmetrically substituted 5,15‐diarylporphyrin 1, with p‐dimethylamino and p‐carbomethoxy substituents, was synthesized via a MacDonald condensation of aryldipyrromethane precursors 6 and 12, which were prepared in good yield by three or four step procedures starting from ethyl 3,4‐dimethyl‐1H‐pyrrole‐2‐carboxylate (2).
Reactions of thioquinanthrene with alkanethiolates. The smiles rearrangement of diquinolinyl sulfides
Authors: Pluta Krystian
Published: March 2009

Reactions of thioquinanthrene 1 with alkali metal alkanethiolates in DMSO or DMF at 70° proceeded through a stage of the S→S type of the Smiles rearrangement (3′‐quinolinethiolate 2A→4′‐quinolinethiolate 3A) to give 4,4′‐dialkylthio‐3,3′‐diquinolinyl sulfides 3 as the final products. When these reactions were carried out at 20° two types of the products were isolated: 3′,4‐dialkylthio‐3,4′‐diquinolinyl sulfides 2 or sulfides 3 depending on the reaction time (1 hour or 7 days). Under acidic conditions 3′‐quinolinethiolate 2A underwent intramolecular cyclization to dithiin 1. Reactions of dithiin 1 with sodium alkanethiolates at 20°, realized as a one‐pot procedure, led to various 3,4‐dialkylthioquinolines 7. The rearrangement of other 3′‐quinolinethiolates 8A and 11A (the products of the reactions of dithiin 1 with sodium sulfide and sodium methoxide) needed higher temperature (140°).
Triazoles XXXVI. The arylation of 5‐amino‐3‐methylthio‐1H‐1,2,4‐triazole with activated aryl chlorides
Authors: Trinka Péter , Reiter József
Published: March 2009

The possibility of the arylation of 5‐amino‐3‐methylthio‐1H‐1,2,4‐triazole (1) with different chlorobenzenes activated by a nitro group was studied. The ratio of products obtained was determined by hplc using isolated products as standards. It was stated that from among the monoarylated products 8, 9 and 10 obtained the main product is 8. However, from the reaction mixtures diarylated derivatives 11 and 12 and different by products such as 15, 16, 22, 24, 25, 27, 28, 32, 36, and 38 were also isolated.
Studies on pyrrolidinones. Synthesis of some N‐fatty acylpyroglutamic acids
Authors: Rigo BenoÎT , Kolokouris Antonios , Kolokouris Nicolas
Published: March 2009

Starting from readily available pyroglutamic acid 1, some N‐fatty acylpyroglutamic acids were synthesized and characterized by their spectral data. A preliminary pharmacological study showed that N‐stearoylpyroglutamic acid 4c displays a CNS stimulating effect on mice.
The reaction of imidazo[1,5‐a]pyridines with methyl‐ and phenyltriazolinediones and with diethyl azodicarboxylate
Authors: Anderson David J. , Watt William
Published: March 2009

Imidazo[1,5‐a]pyridines react in one of two ways with methyl‐ and phenyl triazolinediones and diethyl azodicarboxylate to give either Michael type addition products at C‐3 or C‐1, or novel 1,2,4‐triazolines. The nature of the product depends upon the dienophile and the substitution pattern of the imidazo[1,5‐a]pyridine.
Selective synthesis of monoaryl substituted porphyrins
Authors: Robinsohn Adriana E. , Buldain Graciela Y.
Published: March 2009

A synthetic route to meso‐monoarylporphyrins using a MacDonald‐type 2 + 2 condensation is described. In this method a bisformyl substituted dipyrrylmethane is treated with a biscarboxydipyrrylmethane. The 5‐aryldipyrrylmethanes 15, 25 and 27 were obtained by condensation of the corresponding pyrroles 18, 28 and 29 respectively with benzaldehyde in presence of p‐toluenesulfonic acid.
Studies on pyrrolidinones. Synthesis and reactivity of somen‐protected pyroglutamic derivatives
Authors: Rigo BenoÎT , Erb BÉNÉDicte , El Ghammarti Samira , Gautret Philippe , Couturier Daniel
Published: March 2009

The synthesis of pyroglutamoyl chlorideN‐protected by a methoxycarbonyl or a trifluoroacetyl group is described. Some aspects of the reactivity of these compounds and intermediates have been studied.
Isolation and elucidation of the structure of homocryptolepinone
Authors: Sharaf Maged H. M. , Schiff Paul L. , Tackie Albert N. , Phoebe Charles H. , Davis Ann O. , Webster Andrews C. , Crouch Ronald C. , Martin Gary E.
Published: March 2009

The structure of a new indolobenzazepine alkaloid, homocryptolepinone, isolated from extracts of the roots of the indigenous Ghanaian medicinal plant Cryptolepis sanguinolenta, is reported. The structure was determined using mass spectrometric, one‐dimensional nOe difference nmr, and inverse‐detected two‐dimensional nmr experiments which included HMQC, IDR‐(Inverted Direct Response)‐HMQC‐TOCSY, and HMBC experiments. The structure of homocryptolepinone is significant in that it may provide insight into the biogenesis of the benzpyrrolizinobenzazepine portion of the structure of the complex spiro nona‐cyclic alkaloid cryptospirolepine previously isolated in these laboratories from C. sanguinolenta, and which has no precedent in alkaloid chemistry.
Thieno[2,3‐b]indole. The unsubstituted ring system
Authors: Olesen Preben H. , Hansen John B. , Engelstoft Mogens
Published: March 2009

Methyl thieno[2,3‐b]indolecarboxylate (2) was prepared from methyl 1‐benzylthieno[2,3‐b]indole‐carboxylate by debenzylation with aluminium trichloride in toluene. Compound2was in one step saponified and decarboxylated by heating in morpholine to give the previously unreported parent heterocycle thieno[2,3‐b]indole.
Synthesis of 5,7‐dihydrobenzo[a]phenazin‐5‐one derivatives
Authors: Rehberg Gretchen M. , Rutherford Jennifer L.
Published: March 2009

The synthesis, purification and spectroscopic characterization of several phenazines was undertaken with the goal of discovering useful or improved fluorescent probes.
NOE difference spectroscopy of some 5‐substituted and 5,5‐disubstituted hydantoins
Authors: De Rosa Michael , Freyer Alan J.
Published: March 2009

The nOe difference (NOED) spectra of twelve 5‐substituted‐ and 5,5‐disubstituted hydantoins were recorded in deuteriochloroform. The nOe's observed from the interaction of substituents on C‐5 with the proton on N‐1 are more reliable than the chemical shift of the N‐1 proton for structure determination.
Synthesis of new 1,2,3‐triazolo[1,2‐a]benzotriazoles or 2,3‐benzo‐1,3a,6,6a‐tetraazapentalenes
Authors: Biagi Giuliana , Giorgi Irene , Livi Oreste , Scartoni Valerio , Barili Pier Luigi
Published: March 2009

Some new v‐triazolo[1,2‐a]benzotriazoles or 2,3‐benzo‐1,3a,6,6a‐tetraazapentalenes were prepared according to previously employed synthetic routes concerning deoxycyclization reactions of appropriate nitrophenyl‐1,2,3‐triazole derivatives and/or thermal decompositions of appropriate azidophenyl‐1,2,3‐triazoles. The nitration of 9‐phenyl‐1,2,3‐triazolo[1,2‐a]benzotriazoles allowed the isolation of some mononitro‐ and trinitro‐derivatives, whose structures were assigned by chemical and spectroscopic methods.
Synthesis of some new benzimidazole‐5(6)‐carboxylic acids
Authors: Göker Hakan , Ölgen Süreyya , Ertand Rahmiye , Akgün HÜLya , Özbey Süheyla , Kendi Engin , Topçu GÜL
Published: March 2009

The title compounds, 1,2‐dialkyl‐benzimidazole‐5(6)‐carboxylic acids34–45were prepared at four steps; 1) preparation of mono amide derivatives1–11by the reaction of methyl 3,4‐diaminobenzoate and substituted phenyl or phenoxyacetic acid chlorides; 2) preparation of the methyl benzimidazolecarboxyl‐ates12–22, with zinc chloride and dry hydrogen chloride gas; 3) alkaline hydrolysis of the esters23–33; and 4) substitution of the imidazole ring with benzyl orp‐fluorobenzyl bromide, in alkali medium. 2‐Aryl‐benzimidazole‐5(6)‐carboxylic acids50–53were preparedviathe oxidative condensation of 3,4‐diaminobenzoic acid and aromatic aldehydes with cupric ion.
Novel heterocyclic systems. Synthesis of 10H‐Pyrrolo[1,2‐b][1,2,5]‐benzothiadiazocine 5,5‐dioxide and related derivatives
Authors: Di Santo Roberto , Costi Roberta , Artico Marco , Massa Silvio
Published: March 2009

The synthesis of 10H‐pyrrolo[1,2‐b][1,2,5]benzothiadiazocine 5,5‐dioxide has been carried out by intramolecular cyclization of 1‐(2‐formamidomethylphenylsulfonyl)‐1H‐pyrrole, prepared from the reaction of 1‐(2‐aminomethylphenylsulfonyl)‐1H‐pyrrole with ethyl formate. Treatment of the last pyrrole derivative with triphosgene afforded 10H‐pyrrolo[1,2‐b][1,2,5]benzothiadiazocin‐12(11H)‐one 5,5‐dioxide, which was also prepared by cyclization of 1‐(2‐methoxycarbamidomethylphenylsulfonyl)‐1H‐pyrrole. Methylation of the 12‐one derivative furnished the corresponding ‐methyl benzothiadiazepine dioxide. 1‐(2‐Aminomethylphenylsulfonyl)‐1H‐pyrrole has been prepared by cleavage of the phthalimido moiety of 1‐(2‐phthalimidomethylphenylsulfonyl)‐1H‐pyrrole, obtained by reacting with potassium phmalimide 1‐(2‐bromomethylphenylsulfonyl)‐1H‐pyrrole. This compound has been obtained starting from 2‐bromomethyl‐benzensulfonamide by Clauson‐Kaas procedure.
Aflatoxin analogues as possible anticoagulants. III
Authors: Mouli G. V. P. Chandra , Giridhar T. , Rao D. Mohan , Reddy R. B.
Published: March 2009

The synthesis of a series of derivatives of 4‐hydroxycoumarin analogues of aflatoxin and a preliminary testing of their anticoagulant activity is described.
A straightforward route to 4H‐1,4‐Benzoxazine‐2‐carbaldehydes by swern oxidation
Authors: Bourlot Anne‐Sophie , Guillaumet Gérald , Mérour Jean‐Yves
Published: March 2009

Swern oxidation of saturated (1,4‐benzoxazine‐2‐yl)‐methanols 2 furnished 4H‐1,4‐benzoxazine‐2‐carbaldehydes 3, which possess an α,β ethylenic bond. The reactivity of these compounds was examined.
Furopyridines. XIX. Reaction of furo[2,3‐b]‐, ‐[3,2‐b]‐, ‐[2,3‐c]‐ and ‐[3,2‐c]pyridine with acetic anhydride
Authors: Shiotani Shunsaku , Taniguchi Katsunori , Ishida Toshimasa , In Yasuko
Published: March 2009

Acetoxylation of N‐oxide of furo[2,3‐b]‐ 2a, ‐[3,2‐b]‐ 2b, ‐[2,3‐c]‐ 2c and ‐[3,2‐c]pyridine 2d with acetic anhydride afforded compounds substituted normally at the α‐ or γ‐position to the ring nitrogen, 3a, 4a, 4b, 3d, 4d, 8 and 9, and in addition compounds substituted on the furan ring, 5a, 6a, 5b, 6b, 7b, 5c and 7c which were unexpected compounds. The structures of these compounds were established from the ir, nmr and mass spectra, and x‐ray crystal analysis of 5b.
The synthesis and determination of acidic ionization constants of certain 5‐substituted 2‐aminopyrrolo[2,3‐d]pyrimidin‐4‐ones and methylated analogs
Authors: Hoops Geoffrey C. , Park Julie , Garcia George A. , Townsend Leroy B.
Published: March 2009

The acidic ionization constants were determined for a series of 5‐substituted 2‐aminopyrrolo[2,3‐d]‐pyrimidin‐4‐ones and N‐3‐ and N‐7‐methylated analogs thereof. The syntheses of the methylated analogs are also described.
Nitrogen bridgehead compounds. Part 86. Synthesis and reactivity of 7,12‐dihydropyrimido[1′,2′;1,2]pyrido[3,4‐b]indol‐4(6H)‐ones. Debenzologues of rutaecarpine alkaloids
Authors: Hermecz István , Forgó PÉter , Böcskei Zsolt , Fehér Miklós , Kökösi József , Szász György
Published: March 2009

A series of 7,12‐dihydropyrimido[1′2′:1,2]pyrido[3,4‐b]mdole‐4(6H)‐ones was prepared by Fischer indolization of 9‐arylhydrazono‐6,7,8,9‐tetrahydro‐4H‐pyrido[1,2‐a]pyrirmdin‐4‐ones. Quantum chemical calculations (ab initio and AM1) indicate that position 3 of 7,12‐dihydropyrimido[1′,2′:1,2]pyrido‐[3,4‐b]indole‐4(6H)‐one can be involved in electrophilic substitutions, while position 2 is sensitive towards nucleophilic attack. Bromination of 6‐methyl‐7,12‐tetrahydropyrimido[1′,2′:1,2]pyrido‐[3,4‐b]indol‐4(6H)‐one 16 with bromine afforded 3‐bromo derivative 25, which was reacted with cyclic amines to give 2‐ammo‐7,12‐dihydropyrirmdo[1′2′:1,2]pyrido[3,4‐b]indol‐4(6H)‐ones 26–30 in an addition‐elimination reaction. Vielsmeier‐Haack formylation of compound 16 gave 12‐formyl 31 and 3,12‐diformyl 32 derivatives (an N‐formyl‐1‐deaza derivative of nauclefidine alkaloid 34) at 60° and 100°, respectively. 3,12‐Diformyl compound 32 was oxidized to 3‐carboxyl derivative 33 with potassium permanganate. The quaternary salt 35, obtained from compound 16 with dimethyl sulfate, suffered a ring opening on the action of aqueous sodium hydroxide. The new compounds have been characterized by elemental analyses uv, 1H nmr and in some cases by 13C ruler, CD spectra and X‐ray investigations.
Acylaminoacetyl derivatives of active methylene compounds. 4
Authors: Hamilakis Stylianos , Kontonassios Demetrios , Sandris Constantine
Published: March 2009

Meldrum's acid has been found to be effectively acylated using the imidazolides of N‐protected glycines, X‐NHCH2COOH (X = ‐COPh, ‐COMe, ‐Z, ‐Boc, ‐COOMe and ‐COOEt). The corresponding C‐acylation compounds were isolated in high yields and were readily converted to the N‐protected tetramic acids. It was shown by pmr spectroscopy that these acids exist as the enol tautomers in DMSO‐d6 solution, whereas in deuteriochloroform solution both the enol and keto tautomers can be observed.
Spectroscopic and computational investigation of the ground and low excited states of some symmetrical heterocyclic disulfides
Authors: Stoyanov Stefan , Stoyanova Tatyana , Akrivos Pericles D. , Karagiannidis Petros , Nikolov Peter
Published: March 2009

The electronic absorption and emission spectra of some symmetrical heterocyclic disulfides are investigated. The reversible disulfide — thione transformation in water is discussed in view of the complex equilibrium processes present. UV irradiation and pH influence on the above transformation is also studied. The emission properties at room and low temperature are related to the computed molecular geometries of the ground and low excited states of the compounds.
Photolysis of 2‐azidopyridines. the behavior of 1‐(2‐azido‐6‐chloropyrid‐4‐yl)‐3‐phenylurea, a photoaffinity labeling reagent for probing cytokinin‐binding proteins
Authors: Dias Marylène , Mornet René , Richomme Pascal
Published: March 2009

The photolysis of l‐(2‐azido‐6‐chloropyrid‐4‐yl)‐3‐phenylurea (1) was studied under various conditions. In alcohols or in hexane, complex mixtures of products were obtained. Methoxide anions or diethylamine gave rise in high yield to 1,3‐diazepines resulting from ring enlargement of the intermediate nitrene with addition of one molecule of the nucleophile, and nucleophilic substitution of the chlorine atom. A similar reaction was observed in water, when Pyrex filtered light was used. However, with unfiltered light produced by a powerful lamp, the main reaction was photodechlorination. The reagent 1 is expected to bind covalently to cytokinin‐binding proteins through different ways upon photolysis.
Synthesis and X‐ray study of hexahydro‐ and tetrahydrophospholo‐[2,3‐d]isoxazoles, a new class of heterocycles of potential fungicidal activity
Authors: Machetti Fabrizio , Anichini Beatrice , Cicchi Stefano , Brandi Alberto , Wieczorek Wanda , Pietrusiewicz K. Michal , Gehret Jean‐Claude
Published: March 2009

Hexahydro‐, 5b‐1 and 6a,f,1 and tetrahydrophospholo[2,3‐d]isoxazoles 8, 9 and 10 were synthesized by 1,3‐dipolar cycloaddition of nitrones 3b‐1 and benzonitrile oxide (4) to 2,3‐dihydro‐1‐phenyl‐1H‐phosphole 1‐oxide (1) and 2,3‐dihydro‐1‐ethoxy‐1H‐phosphole 1‐oxide (2). The structural assignment to the compounds was confirmed by an X‐ray study of two compounds of the series 5a and 5m. The compounds show a good activity as fungicides against Plasmopara viticola on vines and against Botrytis cinerea on apples. Compounds 5a‐d showed weak to moderate activity as herbicides.
Syntheses and transformations of substituted benzazolyl‐ and tetrazolyl(benzotriazol‐1‐yl)methanes
Authors: Katritzky Alan R. , Asian Diana , Shcherbakova Irina V. , Chen Jie , Belyakov Sergei A.
Published: March 2009

Condensation reactions of o‐hydroxy‐ and o‐mercaptoanilines, and o‐phenylenediamine with (benzotriazol‐1‐yl)acetic acid result in (1,3‐benzazol‐2‐yl)(benzotriazol‐1‐yl)methanes. Cycloaddition of sodium azide to (benzotriazol‐1‐yl)acetonitrile leads to (1,2,3,4‐tetrazol‐5‐yl)(benzotriazol‐1‐yl)methane. The diazolo‐substituted benzotriazolylmethanes thus obtained were mono‐ and di‐alkylated at the methylene group and the displacement of the benzotriazole group by nucleophiles was investigated.
Photochemically induced reactions of selected ketones with 4‐cyanopyridine in neutral and acidic medium
Authors: Bernardi Rosanna , Caronna Tullio , Morrocchi Sergio , Ursini Maurizio
Published: March 2009

The presence of the 4‐cyanopyridine, in neutral or acidic medium, interferes with the normal behavior of the biradicals obtained by direct excitation of selected ketones, and results in formation of pyridinic derivatives.
3′‐Methylsulfinyl‐3,4′‐diquinolinyl sulfides
Authors: Maślankiewicz Maria J. , Maslankiewicz Andrzej
Published: March 2009

Reactions of 4‐methoxy‐ or 1,4‐dihydro‐4‐oxo‐3′‐methylthio‐3,4′‐diquinolinyl sulfides 1 and 7 with a nitrating mixture ran as the 3′‐methylthio group 5‐mono‐oxidation followed by C6‐ and C8‐nitration and led to the mixture composed of products 3, 4, 5 and 6 (in the case of substrate 1) or compounds 5 and 6 (for substrate 7). In the reaction with hydrochloric acid 4‐methoxy‐3′‐methylsulfinyl‐3,4′‐diquinolinyl sulfides 3 and 4 could be hydrolysed to 3′‐methylsulfinyl‐4(1H)‐quinolinones 5 or 6 respectively, the methylsulfinyl group remaining unaffected.
Selective acetylation of substituted (E)‐4(1H)‐hydroxyimino‐2,3‐dihydro‐1,8‐naphthyridine
Authors: Ferrarini Pier Luigi , Mori Claudio , Belfiore Stefania
Published: March 2009

We report a selective acetylation of compounds 2 in 1‐, 4‐ or 1,4‐position. The treatment of 2 with acetic anhydride gave the compounds 3 and with acetyl chloride the compounds 4. The 1‐acetyl derivatives were obtained starting from 5 via the oxime derivatives 6, 7 and 8. Tests on phytoiatric antimycotic activity and on reactivation of phosphylated acetylcholinesterase and inhibition of acetylcholinesterase were performed.
The synthesis and biological activity of two analogs of the anti‐HIV alkaloid michellamine B
Authors: Upender Velaparthi , Pollart Daniel J. , Liu Jyanwei , Hobbs Peter D. , Olsen Cris , Chao Wan‐Ru , Bowden Bonnie , Crase Jac L. , Thomas David W. , Pandey Anjali , Lawson John A. , Dawson Marcia I.
Published: March 2009

Two simplified analogs of the dimeric naphthalenyltetrahydroisoquinoline alkaloid michellamine B [4′,4″‐didesmethoxy‐2′,2″‐didesmethylmichellamine B and 6,8‐dihydroxy‐5‐(1′,1″‐dihydroxy‐2′,2″‐binaphthalen‐4′‐yl)‐1R,3R‐dimethyl‐1,2,3,4‐tetrahydroisoquinoline] were synthesized using Suzuki palladiumcatalyzed biaryl cross‐coupling of 4‐(2‐benzyl‐6,8‐dibenzyloxy‐1R,3R‐dimethyl‐1,2,3,4‐tetrahydroisoquinolin‐5‐yl)‐1‐benzyloxy‐2‐bromonaphthalene to its corresponding atropisomeric 2‐naphthaleneboronic acid and 1‐benzyloxy‐2‐naphthaleneboronic acid, respectively. These analogs inhibited recombinant HIV reverse transcriptase with IC5() values of 62 μM and 1000 μM, respectively, whereas the IC5() value for michellamine B was 33 μM. Both michellamine B and the analogs inhibited the phosphorylation of histories by rat brain protein kinase C. The analogs were more active (IC50 values of 36 μM and 30 μM, respectively) than michellamine B (IC50 = 130 μM).
Reactions of 1,2,4‐triazines with nitromethide ion. A convenient method of preparation of 1,2,4‐triazin‐5‐ylcarbaldehyde oximes and their synthetic applications
Authors: Rykowski Andrzej , Branowska Danuta , Makosza Mieczyslaw , Van Ly Phan
Published: March 2009

An efficient procedure for the preparation of 1,2,4‐triazin‐5‐ylcarbaldehyde oximes 2a‐f from 1,2,4‐triazines 1a‐f and nitromethide ion is described. The oximes 2c‐d were converted into corresponding 5‐cyano‐1,2,4‐triazines 6c‐d. The latter compounds react easily with various nucleophiles to afford 5‐substituted 1,2,4‐triazines 7a‐i and with 1‐pyrrolidino‐1‐cyclohexene to form cyano derivative of 5,6,7,8‐tetrahydroisoquinoline 9.
Synthesis of substituted pyrrolo[2,3‐e][1,3,4]thiadiazine 4,4‐dioxides
Authors: Stephens Chad E. , Sowell J. Walter
Published: March 2009

A series of substituted pyrrolo[2,3‐e][1,3,4]thiadiazine 4,4‐dioxides is synthesized from 1‐substituted‐2‐amino‐3‐cyanomethylsulfonyl‐4,5‐dimethylpyrroles.
1,3‐Dipolar cycloadditions of electron‐rich benzotriazol‐1‐ylpropenes
Authors: Katritzky Alan R. , Musgrave Richard R. , Breytenbach Jaco C.
Published: March 2009

The preparation of trans‐3‐benzotriazol‐1‐yl‐1‐(N‐rnorpholino)prop‐1‐ene (1), trans‐3‐benzotriazol‐1‐yl‐1‐ethoxyprop‐1‐ene (2) and trans‐1,3‐bis‐(benzotriazol‐1‐yl)propene (3) and their reactions with a benzonitrile oxide (4), N‐(2,4‐dibromophenyl)‐1‐phenylnitrilimine (5), and p‐nitrophenyl azide (6) are described.
Synthesis of 1H‐pyrazino[1,2‐a]pyrido[2,3‐e]pyrazine and 2H‐Pyrano[2,3‐b]pyrido[2,3‐e]pyrazine Derivatives
Authors: Savelli Francesco , Boido Alessandro , Damonte Gianluca
Published: March 2009

With a continuing interest on heteropolycyclic structures which may show biological activities, we synthesized new tricyclic derivatives in which the pyridopyrazine skeleton is fused with pyrazine 7 and 8, B, n = 1. However, the initial design of obtaining also the cyclohomologous structure B (n = 2) produced instead a pyranopyridopyrazine derivative 11. Thus during the attempt to prepare a pyridodiazepine intermediate, beside a very small amount of the desired product 10, the pyridopyrazine 9 was obtained. The latter compound reacted with chloroacetyl chloride/chloroketene to give 4‐carbethoxy‐10‐(chloroacetyl)‐5,10‐dihydro‐5‐methyl‐2H‐pyrano[2,3‐b]pyrido[2,3‐e]pyrazin‐2‐one (11). In studying the behavior of this derivative, compounds 12–14 were obtained. Compounds 4b,c, 5a,b, 7, 8, 9 and 14 have been submitted to preliminary pharmacological screening as CNS depressant agents.
A new method for the synthesis of 4H‐1,3,4‐thiadiazino[5,6‐b]quinoxalines
Authors: Kurasawa Yoshihisa , Sekine Masae , Kim Ho Sik , Okamoto Yoshihisa
Published: March 2009

The reaction of 6‐chloro‐2‐[1‐methyl‐2‐(Mmemylthiocarbamoyl)hydrazino]quinoxaline 4‐oxide 5 with acetic anhydride or trifluoroacetic anhydride resulted in dehydrative cyclization to give 2‐(N‐acetyl)‐memylamino‐8‐chloro‐4‐methyl‐4H‐1,3,4‐thiadiazino[5,6‐b]quinoxaline 6 or 8‐chloro‐2‐(N‐trifluoroacetyl)methylamino‐4‐methyl‐4H‐1,3,4‐thiadiazino[5,6‐b]quinoxaline 9, respectively. The oxidation of compound 6 or 9 with 2‐fold molar amount of m‐chloroperbenzoic acid afforded the 4H‐1,3,4‐thiadiazino‐[5,6‐b]quinoxaline 1,1‐dioxide 8 or 13, respectively. The acetyl group of compound 6 was hardly hydrolyzed, but the trifluoroacetyl group of compound 9 was easily hydrolyzed to change into 8‐chloro‐4‐methyl‐2‐memylamino‐4H‐1,3,4‐thiadiazino[5,6‐b]quinoxaline 10. The acylation of compound 10 with acetic anhydride, trifluoroacetic anhydride, phenyl isocyanate, and chloroacetyl chloride furnished the 2‐(N‐acetyl)methylamino 6, 2‐(N‐trifluoroacetyl)methylamino 9, 2‐(1‐methyl‐3‐phenylureido) 11, and 2‐(N‐chloroacetyl)methylamino 12 derivatives, respectively.
A new synthetic route to 7H‐imidazo[1,2‐b][1,2,4]triazoles
Authors: Lee Kee‐Jung , Song Dong‐Hyuk , Kim Dong‐Jin , Park Sang‐Woo
Published: March 2009

The reaction of benzil 1‐ureidoethylidenehydrazones 8 with a mixture of triphenylphosphine, carbon tetrachloride, and triethylamine provides a general route to 7H‐imidazo[1,2‐b][1,2,4]triazoles 18 via the thermal reaction of the expected ketoazine carbodiimide intermediates 13, and the structure of 18 was confirmed by X‐ray crystallographic analysis.
Syntheses of 5‐hydroxy‐2‐(phenyl or styryl)chromones and of some halo derivatives
Authors: Pinto Diana C. G. A. , Silva Artur M. S. , Cavaleiro José A. S.
Published: March 2009

One‐pot syntheses of 5‐hydroxy‐2‐(phenyl or styryl)chromones and the corresponding 6‐ and 8‐monoiodo‐ and 6,8‐diiodochromones have been developed. The procedures involve oxidative cyclization of 2′‐benzyloxy‐6′‐hydroxychalcones and 2′‐benzyloxy‐6′‐hydroxy‐2‐cinnamylideneacetophenones and electrophilic substitution processes on the chromone moieties; such procedures were also applied to the syntheses of 6,8‐dibromochromone derivatives.
Brominated trimetrexate analogues as inhibitors of pneumocystis carinii and toxoplasma gondii dihydrofolate reductase
Authors: Rosowsky Andre , Mota Clara E. , Queener Sherry E.
Published: March 2009

Five previously undescribed trimetrexate analogues with bulky 2′‐bromo substitution on the phenyl ring were synthesized in order to assess the effect of this structure modification on dihydrofolate reductase inhibition. Condensation of 2‐[2‐(2‐bromo‐3,4,5‐trimethoxyphenyl)ethyl]‐1,l‐dicyanopropene with sulfur in the presence of N,N‐diethylamine afforded 2‐amino‐5‐(2′‐bromo‐3′,4′,5′‐trimethoxybenzyl)‐4‐methyl‐thiophene‐3‐carbonitrile (15) and 2‐amino‐4‐[2‐(2′‐bromo‐3′,4′,5′‐trimethoxyphenyl)ethyl]thiophene‐3‐car‐bonitrile (16). Further reaction with chloroformamidine hydrochloride converted 15 and 16 into 2,4‐diamino‐5‐(2′‐bromo‐3′,4′,5′‐trimethoxybenzyl)‐4‐methylthieno[2,3‐d]pyrimidine (8a) and 2,4‐diamino‐4‐[2‐(2′‐bromo‐3′,4′,5′‐trimethoxyphenyl)ethylthieno[2,3‐d]pyrimidine (12) respectively. Other analogues, obtained by reductive coupling of the appropriate 2,4‐diaminoquinazoline‐6(or 5)‐carbonitriles with 2‐bromo‐3,4,5‐trimethoxyaniline, were 2,4‐diamino‐6‐(2′‐bromo‐3′,4′,5′‐trimethoxyanilinomethyl)‐5‐chloro‐quinazoline (9a), 2,4‐diamino‐5‐(2′‐bromo‐3′,4′,5′‐trimethoxyanilinomethyl)quinazoline (10), and 2,4‐diamino‐6‐(2′‐bromo‐3′,4′,5′‐trimethoxyanilinomethyl)quinazoline (11). Enzyme inhibition assays revealed that space‐filling 2′‐bromo substitution in this limited series of dicyclic 2,4‐diaminopyrimidines with a 3′,4′,5′‐trimethoxyphenyl side chain and a CH2, CH2CH2, or CH2NH bridge failed to improve species selectivity against either P. carinii or T. gondii dihydrofolate reductase relative to rat liver dihydrofolate reductase.
Complete assignment of the 1H and 13C NMR spectra of 4‐methoxy‐3′‐methylsulfinyl‐3,4′‐diquinolinyl sulfides
Authors: Maślankiewicz Maria J. , Maślankiewicz Andrzej
Published: March 2009

The 1H and 13C nmr spectra of 4‐methoxy‐3′‐methylsulfinyl‐3,4′‐diquinolinyl sulfides 2, 3 and 4 were totally assigned using a combination of nmr techniques. As compared to the spectral data of sulfoxide 2 typical values of nitro group substituents effects in nitroquinolines 3 and 4 were observed. The H‐2′ protons in sulfoxides 2, 3 and 4 are strongly influenced by ortho methylsulfinyl group and deshielded by about 0.7 ppm. PM3 method calculations support the structural conclusion that sulfinyl group oxygen points in direction of the positions 2′.
Research on photochemical and thermochemical reactions between indole and quinones in the absence of solvent
Authors: Wang Yong‐Mei , Wen Zhong , Chen Xiao‐Min , Du Da‐Ming , Matsuura Teruo , Meng Ji‐Ben
Published: March 2009

The solid state photochemical reaction of indole with 1,4‐naphthoquinone yielded 5H‐dinaphtho[2,3‐a:‐2′,3′‐c]carbazole‐6,11,12,17‐tetrone (1) in addition to 2‐(3‐indolyl)‐1,4‐naphthoquinone (2) which was also the only product in the solution photoreaction. Solventless thermochemical reactions of indole with phenanthrenequinone in the presence or absence of zinc chloride gave 10‐(1H‐indol‐3‐yl)‐9‐phenanfhrenol (3) and 9,10‐dihydro‐9‐(1H‐indol‐3‐yl)‐10‐(3H‐indol‐3‐ylidene)‐9‐phenanthrenol (4) or 10,10‐di‐1H‐indol‐3‐yl‐9(10H)‐phenanthrenone (5), respectively. All of these products were only obtained in trace amount in corresponding solution reactions, and are different from the adduct 10‐hydroxy‐10‐(1H‐indol‐3‐yl)‐9(10H)‐phenanthrenone (6) obtained in the solution photoreaction. A possible mechanism for formation of 4 and 5 is described in terms of electron pair donor/acceptor complexation.
Synthesis of symmetrical 2,2′,4,4′‐tetrasubstituted[4,4′‐bioxazole]‐5,5′(4H,4′H)‐diones and their reactions with some nucleophiles
Authors: Andersen Kenneth K. , Gloster Daniel F. , Bray Diana D. , Shoja Massud , Kjær Anders
Published: March 2009

Several symmetrical 2,2′,4,4′‐tetrasubstituted[4,4′‐bioxazole]‐5,5′(4H,4′H)‐diones 1a‐f were obtained by dehydrodimerization of 5(4H)‐oxazolones 2a‐f. The configurations of four were established; one by X‐ray crystallography rac‐1c, and three rac‐1a, meso‐1a and rac‐1b by 1H nmr spectroscopy of their derivatives. Upon being heated, the bioxazolones isomerized, presumably by breakage of the 4,4′‐carboncarbon bond to form free radicals followed by their recombination. The results of a crossover experiment were consistent with a radical nature for this isomerization reaction. Treatment of three of the bioxazolones rac‐1a, meso‐1a and rac‐1c with methanol and amine nucleophiles led to ester and amide derivatives 7–11 of α,α'‐dehydrodimeric amino acids.
Metalation of t‐butyl sulfoxides, sulfones and sulfonamides of pyridazine and pyrazine. Metalation of diazines. XX
Authors: Turck Alain , Plé Nelly , Pollet Paméla , Quéguiner Guy
Published: March 2009

In the pyridazine series, the use of tert‐butylsulfinyl and tert‐butylsulfonyl as ortho directing groups for metalation has been tested. Various functionalized products were obtained in good yields. In the case of 3‐tert‐butylsulfinyl‐6‐methoxypyridazine, the metalation was regioselective in ortho to the sulfinyl group. The metalation of 2‐tert‐butylsulfinyl and 2‐tert‐butylsulfonylpyrazine gave low to moderate yields. Synthesis of diazinesulfonamides were improved and the metalation of N‐tert‐butylsulfonamidopyrazine was achieved.
Synthesis of (±)‐methylenolactocin and (±)‐trans cognac lactone
Authors: Ohta Yasuo , Okamoto Takashi , Tamura Masumi , Doe Matsumi , Morimoto Yoshiki , Kinoshita Takamasa , Yoshihara Kazuo
Published: March 2009

The title compounds were efficeintly synthesized from 3‐fuancarboxylic acid via the Birch recuction‐elimination.
Studies on pyrrolidinones. Synthesis of 1‐[(N‐acetylarylamino)methyl]pyroglutamic acid derivatives
Authors: Ghammarti Samira El , Rigo Benoit , Mejdi Hechmi , Hénichart Jean‐Pierre , Couturier Daniel
Published: March 2009

Pyroglutamic acid was transformed into 1‐[(N‐Acetylarylamino)methyl]pyroglutamic acid derivatives by using trimethylsilyl variations of the Mannich reaction.
Some aspects of reduced quinoline chemistry
Authors: Kouznetsov Vladimir , Palma Alirio , Ewert Claude , Varlamov Alexei
Published: March 2009

Different synthetic paths that produce the reduced quinoline cycle are discussed: among them intramolecular cyclization, intra‐ and inter [4+2] cycloaddition reactions and other methods. Some chemical properties of tetrahydroquinolines are also analyzed.
Regioselective epoxide ring opening. Steroselective synthesis of a tetrahydropyran ring
Authors: Gruttadauria Michelangelo , Noto Renato , Riela Serena
Published: March 2009

The stereoselective synthesis of a 2‐substituted tetrahydropyran with adjacent alkoxy‐bearing stereogenic centre is described. The key steps of this synthesis were the stereoselective epoxidation of an allylic alcohol and the regioselective epoxide ring opening by lithium aluminum hydride. The regio and stereoselective synthesis of a trihydroxyselenide and a trihydroxysulfide is also described. The latter compounds are not suitable for cyclization to tetrahydrofuran ring.
An efficient approach to N‐protected 1,2,3,3a‐tetrahydrocyclopenta[b]quinolin‐1‐ones
Authors: Kratzel Martin , Mabhoti Reza
Published: March 2009

In the course of our investigations into the synthesis of benzoanalogues of streptazolin we also studied the construction of 1,2,3,3a‐tetrahydrocyclopenta[b]quinolin‐1‐ones which could be successfully solved by an intramolecular acylation using a bromo‐lithium exchange, starting from 3‐bromoquinoline.
Boron‐containing nucleosides. 1. Synthesis of the novel heterocycle 2‐benzyl‐1,4‐dihydro‐1‐hydroxythieno[3,2‐c][1,5,2]diazaborin‐3(2H)‐one: A thieno‐fused 4‐borauracil
Authors: Graham Steven M. , Ohrtman Loralee M.
Published: March 2009

The synthesis of the novel boron‐containing nucleobase 2‐benzyl‐1,4‐dihydro‐1‐hydroxythieno[3,2‐c]‐[1,5,2]diazaborin‐3(2H)‐one (8), a thieno‐fused 4‐borauracil, is described. Compound 8 was prepared in three steps starting from 2‐thiophenecarbonyl chloride (4). A multinuclear and multisolvent nmr study of 8 indicates that the boron atom maintains a trigonal geometry in the solvents used.
Synthesis of 5‐amino‐1,2,3,4‐tetrahydrobenzo[b][1,7]naphthyridines and 2,3,4,4a,5,6‐hexahydrobenzo[c][2,6]naphthyridines
Authors: Giudice Maria Rosaria Del , Mustazza Carlo , Ferretti Rosella , Borioni Anna , Gatta Franco
Published: March 2009

This paper describes the synthesis of some 5‐amino‐1,2,3,4‐tetrahydrobenzo[b][1,7]naphthyridines and 2,3,4,4a,5,6‐hexahydrobenzo[c][2,6] naphthyridines starting from anilines and 1‐benzyl‐4‐ethoxycarbonylpiperidin‐3‐one. The compounds were prepared in order to study their potential acetylcholinesterase inhibitory activity.
Electrochemical properties of pyrido[1′,2′:1,2]imidazo[4,5‐b]pyrazine and pyrido[1′,2′:1,2]imidazo[4,5‐b]quinoxaline derivatives
Authors: Iwata Satoru , Tanaka Kiyoshi
Published: March 2009

The peak potentials (Ep) of 3‐substituted pyrido[1′,2′:1,2]imidazo[4,5‐b]pyrazine and pyrido[1′,2′:1,2]‐imidazo[4,5‐b]quinoxaline derivatives are sufficiently correlated with Hammett substituent constant ∼m and with the PM3 calculated LUMO energy levels, and the linear relationship between electron potentials of 9‐substituted pyridoimidazoquinoxalines and the LUMO energy levels is also found out.
Purines XIV.. Reactivity of 8‐bromo‐3,9‐dimethylxanthine towards some nucleophilic reagents
Authors: Youssef Shaker , Pfleiderer Wolfgang
Published: March 2009

The reactivity of 8‐bromo‐3,9‐dimethylxanthine (6) towards a variety of nucleophilic reagents has been investigated. Nucleophilic displacements take place easily with aliphatic mercaptans and aliphatic alcohols, whereas aliphatic amines required more severe conditions. Prolonged heating of 6 with amines causes a new type of rearrangement from 3,9‐ to 3,7‐dimethylxanthines due to a 1,3‐sigmatropic shift of the N(9)‐methyl group.
Synthesis of 2‐(p‐R‐benzoylmethylene)‐3‐(p‐R‐phenyl)‐1H‐quinoxalines
Authors: Insuasty Braulio , Fernéandez Fernando , Quiroga Jairo , Moreno Rodolfo , Martinez Roberto , Angeles Enrique , Gaviñto Rubéan , De Almeida Regina H. S.
Published: March 2009

The reaction of 1,2‐diaminobenzenes with substituted 1,2‐dibenzoyl‐1,2‐dibromoethanes constitutes a convenient synthetic route to the hitherto 2‐(p‐R‐benzoylmethylene)‐3‐(p‐R‐phenyl)‐1H‐quinoxalines. Structures of all products were elucidated by ir, 1H and 13C‐nmr, mass spectra data. X‐Ray crystallography data confirm assigned structures.
Imidazo[1,2‐b]pyridazines: Syntheses and interaction with central and peripheral‐type (mitochondrial) benzodiazepine receptors
Authors: Barlin Gordon B.
Published: March 2009

The fundamental chemistry of pyridazines, the syntheses of substituted irnidazo[1,2‐b]pyridazines (1) (and some related compounds) and the interaction of the products with central benzodiazepine receptors (CBR) and peripheral‐type (mitochondrial) benzodiazepine receptors (PBR) are described.

Some of these imidazo[1,2‐b]pyridazines had high selective affinity for the central benzodiazepine receptors and others had high selectivity for the peripheral‐type (mitochondrial) benzodiazepine receptors. The results of structure‐activity studies and molecular modeling will be reported.

In vivotests of some compounds which interacted strongly with the central benzodiazepine receptors revealed reasonably potent anticonvulsant/anticonflict activity, and some of those which bind selectively to the peripheral‐type (mitochondrial) benzodiazepine receptors are being examined as possible radiopharmaceuticals for imaging of tumors (and other disease states).
Furopyridines. XXVI. Reactions of cyanopyridine derivatives of furo[2,3‐b]‐, ‐[3,2‐b]‐, ‐[2,3‐c]‐ and ‐[3,2‐c]pyridine
Authors: Yamaguchi Sciji , Saitoh Hideo , Kurosaki Masahide , Yokoyama Hajime , Hirai Yoshiro , Shiotani Shunsaku
Published: March 2009

Bromination of α‐cyanopyridine derivatives of furopyridines 1a‐d gave the 2,3‐dibromo‐2,3‐dihydro compounds 2a‐d in excellent yields. Treatment of 2a‐d with sodium hydroxide in methanol yielded compounds formed through the dehydrobromination and solvolysis of the nitrile. N‐Oxidation of 1a and 1b gave N‐oxide in much poor yield, while 1c and 1d gave the N‐oxide 13c and 13d in good yields. The nucleophilic reactions (cyanation, chlorination and acetoxylatoin) of 13c through a Reissert‐Henze type reaction gave poor results, which would be caused by the strong electron withdrawing effect of the cyano group.
Furopyridines. XXIX. Reactions of furo[2,3‐b:4,5‐c‘]‐, ‐[3,2‐b:‐4,5‐c’]‐, ‐[2,3‐c:4,5‐c‘]‐ and ‐[3,2‐c:3,2‐c’]dipyridine
Authors: Yamaguchi Seiji , Orito Keiko , Shimizu Noriko , Taniguchi Katsunori , Saitoh Hideo , Kurosaki Masahide , Yokoyama Hajime , Hirai Yoshiro , Shiotani Shunsaku
Published: March 2009

Furo[2,3‐b:4,5‐c‘]‐ 1a, ‐[3,2‐b:4,5‐c’]‐ 1b, ‐[2,3‐c:4,5‐c‘]‐ 1c and ‐[3,2‐c:4,5‐c’]dipyridine 1d were derived to the N‐oxides 2a‐d, N‘‐oxides 2′b, 2′c or N,N’‐dioxide 3b‐d by N‐oxidation with m‐chloroperbenzoic acid. Chlorination of these N‐oxides, N′‐oxide and N,N′‐dioxides with phosphorus oxychloride afforded compounds chlorinated at the α‐position(s) to the ring nitrogen 4a‐d, 4′c, 14b‐d and 14′b. Acetoxylation of N‐oxides 2a‐d and 2′c with acetic anhydride gave the corresponding pyridone compounds 6a‐d and 6′c in good yields, while the acetoxylation of N,N′‐dioxides gave a complex mixture from which no compound could be isolated. Cyanation of 2a‐d, 2′c and 3b‐d with trimethylsilyl cyanide yielded the cyano compounds 7a‐d, 7′c, cyano‐N‐oxides 15b‐d and dicyano compounds 15′c and 15′d. Monocyano compounds 7a‐d and 7′c were converted to the imino esters 8a‐d and 8′c by treatment with sodium ethoxide. Imino esters were derived to the carboxylic esters 9a‐d and 9′c, from which the corresponding alde hydes 10a‐d and 10′c were obtained by reduction with diisobutylaluminum hydride. Dicyanide 15′c was converted to dialdehyde 19 by the treatment with sodium ethoxide, and the subsequent hydrolysis of the imino ester and reduction of the carboxylic ester with diisobutylaluminum hydride.
2‐aminothiophenes by the gewald reaction
Authors: Sabnis R. W. , Rangnekar D. W. , Sonawane N. D.
Published: March 2009

The review presents the most elegant and promising set of synthetic routes for the synthesis of 2‐aminothiophenes by the Gewald reaction. Applications of this facile methodology to pharmaceuticals and dyestuffs have been demonstrated.