bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemoselective preparation of ketones by the grignard reaction of N‐acylpyrazoles
Authors: Kashima Choji , Kita Isanobu , Takahashi Katsumi , Hosomi Akira 
Published: March 2009

AbstractN‐Acylpyrazoles afford chemoselectively the corresponding ketones in good yields by the use of equimolar amounts of Grignard reagent. In the case of an optically active N‐acylpyrazole, optical asymmetry was retained in comparable optical yield. Ketone formation by the Grignard reactions can be regarded as an important functionalization in a synthetic loop using pyrazoles as the auxiliary compound.
First synthesis of chiral 3‐vinylindoles as 4π‐components for diels‐alder reactions
Authors: Pindur Ulf , Lutz Gundula , Rogge Martina 
Published: March 2009

AbstractThe first syntheses of chiral 3‐ and 2‐vinylindoles bearing sulfoxide or (‐)‐menthyloxy functional groups at the β‐vinyl positions by way of procedures based on the Horner‐Wadsworth‐Emmons and Wittig reactions, respectively, are described. Some Diels‐Alder reactions demonstrating the 4π‐reactivity of these compounds are reported.
Synthesis and biological activities of tetrahydroquinazoline analogs of aminopterin and methotrexate
Authors: Gangjee Aleem , Zaveri Nurulain , Queener Sherry F. , Kisliuk Roy L. 
Published: March 2009

Abstract(6R,6S)‐5,8‐Dideaza‐5,6,7,8‐tetrahydroaminopterin (1) and (6R,6S)‐5,8‐dideaza‐5,6,7,8‐tetrahydromethotrexate (2) were synthesized as potential inhibitors of dihydrofolate reductase (DHFR) and as antitumor agents. Cyclohexanone‐4‐carboxaldehyde dimethyl acetal, a key intermediate [10] was synthesized from cyclohexane‐1,4‐dione monoethylene ketal, which was converted via a Wittig reaction to its exocyclic 4‐methylene derivative which in turn, was converted to the 4‐aldehyde via a hydroboration‐oxidation sequence. Selective protection of the 4‐aldehyde as the dimethylacetal and cyclization with dicyandiamide afforded the 6‐dimethylacetal of 2,4‐diamino‐5,6,7,8‐tetrahydroquinazoline. Protection of the 2,4‐diamino moieties and selective deprotection of the 6‐aldehyde followed by reductive amination with p‐aminobenzoyl‐L‐glutamate afforded 2,4‐bisacetamido‐5,8‐dideaza‐5,6,7,8‐tetrahydroaminopterin (11). Deprotection of 11 afforded 1. Compound 2 was obtained from 11 via N10‐methylation and deprotection. The N10‐methyl analogue 2 was 2–10 fold more potent than 1 as an inhibitor of various DHFRs. In the in vitro preclinical screening program of the National Cancer Institute, compound 2 inhibited the growth of eighteen of the twenty nine tumor cell lines in culture at a GI50 > 1.0 × 10−8 M.
Synthesis and reactions of lithio derivatives of 1‐allenylbenzotriazole
Authors: Katritzky Alan R. , Verin Sergei V. 
Published: March 2009

Abstract1‐(2‐Chloropropen‐2‐yl)benzotriazole (6) is converted by heating with sodium hydroxide or by lithium diisopropylamide at ‐78° into 1‐allenylbenzotriazole (1) in high yield. Allene 1 undergoes in situ lithiation at the α‐carbon and subsequent reactions with iodomethane or carbonyl compounds to produce 1‐(1‐substituted allenyl)benzotriazoles 9 and 2a‐c, respectively. Three equivalents of lithium diisopropylamide dilithiated 1 and afforded symmetrical 1‐(1,3‐disubstituted allenyl)benzotriazoles 11a,b upon reaction with ketones. The unsymmetrical 1‐(1,3‐disubstituted allenyl)benzotriazole 5 was obtained via a stepwise addition of benzophenone to the lithio derivative of 1 followed by a second lithiation and quenching with acetone. Monosubstituted allenes 2a and 8 were cyclized into the benzotriazolyl substituted dihydrofuran 3 and dihydropyrrole 4 respectively.
Synthesis of novel 1‐alkyl or 1‐aryl‐2‐(4‐substituted‐1‐piperazinyl)‐1‐H‐benzothieno[2,3‐d]imidazoles
Authors: Guerrera F. , Salerno L. , Sarvà M. C. , Siracusa M. A. 
Published: March 2009

AbstractThe synthesis of novel 1‐alkyl or 1‐aryl‐2‐(4‐substituted‐1‐piperazinyl)‐1‐H‐benzothieno[2,3‐d]imidazoles 7e‐x starting from 2‐nitro‐3‐bromobenzo[b]thiophene is described. These compounds were prepared as potential H1‐antihistaminic agents.
Chemical and electrochemical reduction of some pyrazolo[1,5‐a]pyrimidines
Authors: Bellec Christian , Lhommet GÉRard 
Published: March 2009

AbstractVarious pyrazolo[1,5‐a]pyrimidines 1 are prepared by two different ways. Their chemical reduction by sodium borohydride leads generally to 4,5,6,7‐tetrahydro compounds 3, while lithium aluminum hydride yields 4,7‐dihydro derivatives 2 at room temperature, and 3 in refluxing tetrahydrofuran. A complex mixture of oxidizable hydrodimers is obtained by electrochemical reduction. An electroreduction at a more negative potential also gives 4,7‐dihydro compounds 2. A new 4,5‐dihydropyrazolo[1,5‐a]pyrimidine has been obtained by condensation of 5‐amino‐3‐methyl‐1H‐pyrazole with acetophenone.
Photochromism of fulgides and stereoelectronic factors: Synthesis of (E)‐4(3)‐adamantyhdene‐(5)‐dicyanomethylene‐3(4)‐[1‐(2,5‐dimethylfuryl)ethylidene]tetrahydrofuran‐2‐one 4 and 4a and (E)‐4‐adamantylidene‐3‐[2,6‐dimethyl‐3,5‐bis(p‐diethyl‐aminostyryl)benzylidene]tetrahydrofuran‐2,5‐dione 10
Authors: Sun Zhiyuan , Hosmane Ramachandra S. , Tadros Maher , Guha Shekhar , Chen Wenpeng , Chen Jar‐Mo 
Published: March 2009

AbstractIn the search for fulgides with potential semiconductor laser compatibility, 4‐adamantylidene‐5‐dicyanomemylene‐3‐[1‐(2,5‐dimethyl‐3‐furyl)ethylidene]tetrahydrofuran‐2‐one (4), along with its regioisomer 4a, have been synthesized from the corresponding fulgide 6 containing a succinic anhydride ring by reaction with malononitrile in the presence of diethylamine. Upon irradiation with a uv light at λmax 350 run, a mixture of 4 and 4a revealed a considerably enhanced bathochromic shift to the visible region, λmax 605 nm as compared with the starting fulgide 6 which, upon analogous uv irradiation, absorbed at λmax 515 nm. In the search for semiconductor‐laser‐compatible fulgides with increased efficiency for the reverse bleaching reaction, another fulgide (E)–adamantylidene‐3‐[2,6‐dimethyl‐3,5‐bis(p‐diethylaminostyryl)‐benzylidene]tetrahydrofuran‐2,5‐dione (10) was synthesized in seven steps starting from 2‐bromo‐m‐xylene. However, 10 failed to undergo electrocyclic ring‐closure upon irradiation with a uv light at λmax 350 nm. The analogous fulgide 8, which contains an isopropylidene functionality in place of the adamantyl group of 10, was resynthesized for comparison, and showed two absorption maxima, one at 545 nm and the other at 620 nm. The missing physico‐chemical data for 8 have also been provided.
Polycyclic arene sulfides. Preparation of 1a,2,3,11b‐tetrahydrobenz‐[5,6]anthra[1,2‐b]thiirene, 6b,7a,8,9‐tetrahydrobenzo[10,11]‐chryseno[1,2‐b]thiirene, and 7,8,8a,9a‐tetrahydrobenzo‐[10,11]chryseno[3,4‐b]thiirene
Authors: Shalom Yosef , Kogan Vladimir , Badriah Yacoub , Harvey Ronald G. 
Published: March 2009

AbstractThe title compounds 5, 7 and 9 which are the first arene sulfides of 7,8‐dihydrobenz[a]anthracene, 8,9‐and 10,11‐dihydrobenzo[a]pyrene, respectively, have been synthesized by treatment of the corresponding arene oxides 4, 6 and 8 with N,N‐dimethylthioformamide in the presence of catalytic amounts of trifluoroacetic acid.
The synthesis of novel polycyclic heterocyclic ring systems via photocyclization. 17. Thieno[3′,2′:4,5]thieno[2,3‐c]naphtho‐[2,1‐f]quinoline and thieno[3′,2′:4,5]thieno[2,3‐c]‐naphtho[1,2‐g]quinoline
Authors: Luo Jiann‐Kuan , Federspiel Ronald F. , Castle Raymond N. , Castle Lyle W. 
Published: March 2009

AbstractThe synthesis of two previously unknown novel polycyclic heterocyclic ring systems via photocyclization is described. The structural assignment of the isomeric ring systems, 4 and 5, was achieved by the total assignment of their 1H and 13C nmr spectra by the concerted usage of two‐dimensional nmr methods.
Synthesis of some novel 2‐phenylpyridazino[4,5‐b][1,5]thiazepines
Authors: Mátyus Péter , Zára‐Kaczián Erzsébet , Boros SÁNdor , Böcskei Zsolt 
Published: March 2009

AbstractSynthesis of some derivatives of the pyridazino[4,5‐b][1,5]thiazepine ring system is reported. Thus, 5‐benzyl‐8‐methyl‐2‐phenyl‐2,3.4,5‐tetrahydro‐5H‐pyridazino[4,5‐b][1,5]thiazepin‐9(8H)‐one (5) was prepared by an intramolecular S‐alkylation reaction, whereas the thiazepine ring of sulfone analogue 21, and that of the novel tricyclic pyrrolidino fused ring system 22 was elaborated by an intramolecular C‐alkylation reaction. Unexpected formation of bicyclic pyrido‐ and thiazine fused pyridazine systems are also discussed.
Retro‐ene reactions. III. Alkylation of 4,5‐dichloro‐1‐hydroxymethylpyridazin‐6‐ones: Synthesis of 4,5‐dichloro‐1‐(ω‐phthalimido and saccharin‐2′‐ylalkyl)pyridazin‐6‐ones
Authors: Kim Sung‐Kyu , Cho Su‐Dong , Moon Jung‐Kyen , Yoon Yong‐Jin 
Published: March 2009

Abstract4,5‐Dichloro‐1‐(ω‐phthalimido and saccharinyl‐2′‐ylalkyl)pyridazin‐6‐ones were synthesized from 4,5‐dichloro‐1‐hydroxymethylpyridazin‐6‐one and the corresponding N‐(ω‐haloalkyl)phthalimides and saccharins via a fragmentation of retro‐ene type.
A new synthesis of 1,5‐dihydropyridazino[3,4‐b]quinoxalines and 2‐(pyrazol‐4‐yl)quinoxalines
Authors: Kurasawa Yoshihisa , Takano Akiko , Kato Kyoko , Takada Atsushi , Kim Ho Sik , Okamoto Yoshihisa 
Published: March 2009

AbstractThe reaction of 6‐chloro‐2‐(l‐methylhydrazino)quinoxaline 1‐oxide 3 with acetylenedicarboxylates gave the 8‐chloro‐1‐memyl‐1,5‐dihydropyridazino[3,4‐b]quinoxaline‐3,4‐dicarboxylates 4a,b and 2‐(pyrazol‐4‐yl)quinoxaline 1‐oxides 5a,b. The formation of compounds 4a,b would follow the 1,3‐dipolar cycloaddition reaction, subsequent 1,2‐hydrazino migration, and then dehydrative cyclization, while the production of compounds 5a,b would proceed via the addition of the hydrazino group to acetylene‐dicarboxylate leading to the construction of a pyrazole ring, followed by rearrangement of the pyrazole ring. Compounds 5a,b were deoxidized with phosphoryl chloride/N,N‐dimethylformamide to change into the 4‐(quinoxalin‐2‐yl)pyrazole‐3‐carboxylates 8a,b.
Synthesis of heterocyclic sulfonylureas
Authors: Löwe Werner , Matzanke Norbert 
Published: March 2009

AbstractWe examined the scope of the previously reported one‐pot synthesis [1] of chromone‐3‐sulfonylureas. Different anilines and heterocyclic amines were thereby reacted with chlorosulfonyl isocyanate‐derived chlorosulfonylureas. These were treated with different enaminones and enamines to provide the title compounds.
Addition of trimethylsilyl azide and of “mixed anhydrides” to the N‐C(3) σ‐bond in 3‐substituted‐1‐azabicyclo[1.1.0]butanes
Authors: Marchand Alan P. , Sharma G. V. M. , Rajagopal D. , Shukla Rajesh , Mlostoń Grzegorz , Bartnik Romuald 
Published: March 2009

AbstractTrimethylsilyl azide adds smoothly to the highly strained N‐C(3) σ‐bond in 3‐ethyl‐1‐azabicyclo[1.1.0]‐butane (1) to afford an adduct, 2, that reacts in situ with a variety of electrophilic reagents (i.e., ethyl chloroformate, p‐toluenesulfonyl chloride, benzoyl chloride, acetyl chloride, and oxalyl chloride) to afford the corresponding N‐substituted‐3‐azido‐3‐ethylazetidines 3–7, respectively in 62–72% yield. Similarly, 1 reacts regiospecifically with “mixed anhydrides” (i.e., p‐toluenesulfonyl acetate, methanesulfonyl acetate, and benzoyl trifluoromethanesulfonate) to afford the corresponding adducts, 8–10, respectively) in 38–68% yield. Reaction of p‐toluenesulfonyl azide with 1‐aza‐3‐phenylbicyclo[1.1.0]butane (12) produces two products: N‐(p‐toluenesulfonyl‐3‐azido‐3‐phenylazetidine (13, 15%) and a dimeric product, N‐(N'‐p‐toluenesulfonyl‐3′‐phenyl‐3′‐azetidinyl)‐3‐azido‐3‐phenylazetidine (14, 28%). Ethyl chloroformate adds to the N‐C(3) σ‐bond in 1‐aza‐3‐(bromomethyl)bicyclo[1.1.0]butane (15) to afford N‐carboethoxy‐3‐(bromomethyl)‐3‐chloroazetidine (16) in 73% yield.
Synthesis of 1‐ and 2‐(2‐quinolyl)azulenes by the friedländer reaction of acetylazulenes
Authors: Mori Takahiro , Imafuku Kimiaki , Piao Ming‐Zhu , Fujimori Kunihide 
Published: March 2009

Abstract1‐Acetylazulene and 3‐methyl‐, 3‐ethyl‐, and 3‐propyl‐substituted 1‐acetylazulenes were prepared by the reaction of 3‐acetyl‐2H‐cyclohepta[b]furan‐2‐one with in situ generated enamines from aldehydes and amines. These four 1‐acetylazulenes reacted with 2‐aminobenzaldehyde and its 4,5‐dimethoxy‐ and 4,5‐methylenedioxy‐substituted derivatives in the presence of sodium ethoxide to afford twelve 1‐(2‐quinolyl)azulenes. In a similar manner, three 2‐(2‐quinolyl)azulenes were also prepared from 2‐acetylazulene.
[1]Benzothienoindolizidinones and [1]benzothienoquinolizidinones: Synthesis and schmidt rearrangement into [1,3]diazepines derivatives
Authors: Daïcb Adam , Decroix Bernard 
Published: March 2009

Abstract[1]Benzothienoindolizidinones 5ac,ae,bc and [1]Benzothienoquinolizidinone 5ad were synthesized from 2(3)‐bromethyl[1]benzothiophene and methyl prolinate, methyl oxoprolinate and ethyl pipecolinate. The Schmidt rearrangement of ketones 5 led exclusively to the [1,3]diazepines derivatives 6.
Diethyl N,N‐dimethylaminomethylenemalonate in the synthesis of fused heterocyclic systems
Authors: Kušar Mihael , Svete Jurij , Stanovnik Branko 
Published: March 2009

AbstractThe reactions of diethyl N,N‐dimethylaminomethylenemalonate (3) with N‐ and C‐ nucleophiles were studied. In the reaction of 3 with heterocyclic amines 4, with the amino group attached at α‐position in respect to the ring nitrogen atom, substitution of the dimethylamino group in 3 with the heterocyclic amino took place to give diethyl heteroarylaminomethylenemalonates 5, which can cyclize into fused azino‐ 6 or azolopyrimidinones 7. In the reaction of 3 with the compound with an active methylene group attached at α‐position in regard to the ring nitrogen atom, such as pyridinylacetonitrile (8), ethyl pyridinyl‐ (9), and quinolinylacetate (10), fused quinolizines 11 and 12, and benzo[c]quinolizine 13 were formed, respectively. Heterocyclic systems with an active or potentially active methylene group incorporated in the ring system, such as pyrazole 14, pyrimidine 15, and pyridine derivative 18, gave with 3 fused pyranones 16, 17, and 19, and dihydroxynaphthalenes 22 and 23 naphtho[2,1‐b]pyranones 24 and 25.
Aroylation of 5‐amino‐2H‐1,2,4‐thiadiazolin‐3‐ones
Authors: Cho Nam Sook , Ra Chan Soo , Ra Do Young , Song Jin Soo , Kang Sung Kwon 
Published: March 2009

Abstract2‐Aroyl‐5‐aroylamino‐1,2,4‐thiadiazolin‐3‐ones (2) have been synthesized through aroylation of 5‐arruno‐2H‐1,2,4‐thiadiazolin‐3‐one (1) as an analog of cytosine. The aroylation was carried out with a substituted aroyl chloride in pyridine at 56∼58°C. It has been established that the intermediates of the reactions are 2‐aroyl‐5‐amino‐1,2,4‐thiadiazolin‐3‐ones (3) on the basis of the spectral data, additional experimental information and ab initio molecular orbital calculations.
3,6‐Thioanhydro sugar derivatives. An enantiospecific synthesis of (2R,3R,4S)‐3‐benzyloxy‐4‐hydroxy‐2‐[(R)‐1‐benzyloxy‐4‐hydroxybutyl]thiolane as the key intermediate for thioswainsonine
Authors: Izquierdo Isidoro , Plaza Maria T. , RamYírez Antonio , Aragón Fida 
Published: March 2009

AbstractMethyl 2‐O‐benzyl‐3,6‐thioanhydro‐α‐D‐mannopyranoside (9) was obtained in eight steps from the commercially available methyl α‐D‐glucopyranoside. Compound 9 was transformed into (2R,3R,4S)‐3‐benzyloxy‐4‐hydroxy‐2‐[(R)‐1‐benzyloxy‐4‐hydroxybutyl]thiolane (14) by acid hydrolysis of its 2,4‐di‐O‐benzyl derivative 10 followed by reaction of the not isolated 2,4‐di‐O‐benzyl‐3,6‐thioanhydro‐D‐mannose (11) with ethoxycarbonylmethylenetriphenylphosphorane to give an = 1:1 E/Z mixture of the corresponding α,β‐unsaturated ester (12). Finally, catalytic hydrogenation of 12 to ethyl (R)‐4‐benzyloxy‐4‐[(2′R)3′R,4′S)‐3′‐benzyloxy‐4′‐hydroxythiolan‐2′‐yl]butanoate (13) and subsequent reduction with lithium aluminum hydride gave the title compound 14.
The reaction of vinyl ethers with acridine
Authors: Takano Rumi , Ishihara Yoshimi , Saito Hiroshi , Kitahara Takio , Takano Jiro 
Published: March 2009

AbstractThe reaction of vinyl ethers with acridine gives new acridine derivatives in the presence of an organic ammonium salt and alcohol. An organic ammonium salt such as acridinium chloride affect this reaction. All of the addition products were obtained as dihydroacridinyl derivatives. Moreover, in the reaction of ketene silyl acetal with acridine, the addition products were also obtained as the dihydroacridine derivatives.
Synthesis and chemistry of the ionophore antibiotic tetronasin
Authors: Ley Steven V. , Clase J. Andrew , Mansfield Darren J. , Osborn Helen M. I. 
Published: March 2009

AbstractStudies towards the synthesis and biosynthesis of tetronasin, an acyltetronic acid ionophore are described, together with an account of some novel methodology which is more widely applicable for the synthesis of other acyltetronic acids.
The synthesis of 8‐allyl‐2‐styrylchromones by the modified baker‐venkataraman transformation
Authors: Reddy B. Parthasarathi , Krupadanam G. L. David 
Published: March 2009

AbstractSubstituted‐2‐hydroxy‐3‐allylacetophenones 2 react with cinnamoyl chlorides 3 in potassium carbonate‐acetone to give good yields of polyfunctional 1‐(2‐hydroxy‐3‐allylaryl)‐5‐aryl‐4‐pentene‐1,3‐diones 4 which exist in their enol forms 5. These on acid catalysed cyclodehydration gave 70–80% yields of substituted 8‐allyl‐2‐styrylchromones 6.
Haloacetylated enol ethers. 7 . Synthesis of 3‐aryl‐5‐trihalomethylisoxazoles and 3‐aryl‐5‐hydroxy‐5‐trihalomethyl‐4,5‐dihydroisoxazoles
Authors: Martins Marcos A. P. , Siqueira Geonir M. , Bastos Giovani P. , Bonacorso Helio G. , Zanatta Nilo 
Published: March 2009

Abstractβ‐Aryl‐β‐methoxyvinyl trihalomethyl ketones 1a‐g, 2a‐g [aryl = p‐YC6H4 where Y= H, Me, OMe, F, Cl, Br, NO2] are cyclocondensed with hydroxylamine hydrochloride to afford the 3‐aryl‐5‐hydroxy‐5‐trihalomethyl‐4,5‐dihydroisoxazoles 3a‐g, 4a‐f in good yield. The dehydratation of compounds 3a‐g with concentrated sulfuric acid, led the corresponding 3‐aryl‐5‐trichloromethylisoxazoles 5a‐g. An alternative one‐pot procedure yields 3‐aryl‐5‐trihalomethylisoxazoles 5,6a‐g directly by cyclocondesation of 1,2a‐g with hydroxylamine hydrochloride in the presence of an excess of concentrated hydrochloric acid.
Syntheses for 2‐amino and 2‐mercapto‐2H‐1,4‐benzoxazin‐3(4H)‐one and 2H‐1,4‐benzothiazin‐3(4H)‐one as aza and thio analogues of the natural product blepharigenin
Authors: Kluge Michael , Sicker Dieter 
Published: March 2009

Abstract2‐Amino‐2H‐1,4‐benzoxazin‐3(4H)‐one 3, 2‐amino‐2H‐1,4‐benzothiazin‐3(4H)‐one 4, 2‐mercapto‐2H‐1,4‐benzoxazin‐3(4H)‐one 7, and 2‐mercapto‐2H‐1,4‐benzothiazin‐3(4H)‐one 8 representing aza and thio analogues of the natural product's aglucone Blepharigenin (2‐hydroxy‐2H‐1,4‐benzoxazin‐3(4H)‐one) from Gramineae and Acantnaceae species have been synthesized for the first time from their 2‐bromo precursors 1 and 2. Attempts to similarly prepare the 4‐hydroxy derivatives of 7 and 8, which would represent new thio analogues of the naturally occurring cyclic hydroxamic acid, 2,4‐dihydroxy‐2H‐1,4‐benzoxazin‐3(4H)‐one, have failed.
Synthesis and spectral properties of isomeric [(12‐N‐methyl) and (10‐N‐methyl)]‐11‐(o, and p‐substituted‐anilino)‐5H‐dibenzo[b,e][1,4]diazepines
Authors: Cortés Eduardo Cortés , Islas Pedro Muñoz , García Marcos Martínez , Romero Mayra O. Zepeda 
Published: March 2009

AbstractThe preparation of sixteen novel substituted [(10‐N‐methyl) and (12‐N‐methyl)]‐11‐(o‐, and p‐substituted‐anilino)‐5H‐dibenzo[b,e][1,4]diazepines which have potentially useful pharmacological properties is described. The structure and the isomeric differences in all products was corroborated by ir, 1H‐nmr, 13C‐nmr, and mass spectra.
New trifluoromethylated pyridines from functionalized N1‐acylacetamidrazones
Authors: Cocco Maria Teresa , Congiu Cenzo , Onnis Valentina , Bernard Angela Maria , Piras Pier Paolo 
Published: March 2009

AbstractPolyfunctionalized trifluoromethylpyridines 4, 5 were readily synthesized from trifluoroacetylvinyl ether 3, using N1‐acylacetamidrazones 1,2 as starting material.
Iminium carbonic acid derivative salts. IX. Synthesis of N,S‐containing heterobicycles from N‐protected 2‐methylthio‐1,3‐thiazinium and 2‐methylthiothiazolium salts part 1. Preparation of N‐protected 2‐methylthio‐1,3‐thiazinium and 2‐methylthiothiazolium salts and their reaction with CH‐acidic compounds
Authors: Hanefeld Wolfgang , Naeeni Mahmoud , Schlitzer Martin 
Published: March 2009

AbstractN‐Boc‐protected 1,3‐thiazine‐2‐thiones and thiazolidin‐2‐thiones were transformed into the corresponding 2‐methylthio‐1,3‐thiazinium and 2‐methylthiothiazolium salts by methyl iodide or trimethyloxonium tetrafluoroborate. This activated species were reacted with CH‐acidic compounds forming ketene‐N,S‐acetals. The protection group was removed with trifluoracetic acid to yield the N‐unsubstituted ketene‐N,S‐acetals.
A facile preparation of some novel class II mesoionic xanthine acyclonucleosides
Authors: Giandinoto Salvatore , Mbagwu Godwin O. , Robinson Tamara A. , Ferguson Chantel , Nunez Jacqueline 
Published: March 2009

AbstractThe synthesis of the first examples of Class II mesoionic xanthine acyclonucleosides is described. A series of mesoionic anhydro‐(8‐methoxyalkyl‐5‐hydroxy‐7‐oxothiazolo[3,2‐a]pyrimidinium hydroxides), Class II mesoionic analogs isoconjugate with xanthine, were prepared by the thermal condensation of methoxyalkyl‐2‐aminothiazoles with substituted bis(2,4,6‐trichlorophenyl)malonic esters. The memoxyalkyl‐2‐aminothiazoles were prepared via an aromatic nucleophilic substitution reaction between 2‐bromothiazole and the appropriate methoxyalkylamine in excess. The resulting 8‐methoxyalkyl‐substituted mesoionic xanthines were demethylated using iodotrimethylsilane in acetonitrile at room temperature to afford the corresponding mesoionic anhydro‐(8‐hydroxyalkyl‐5‐hydroxy‐7‐oxothiazolo[3,2‐a]pyrimidinium hydroxides) as the Class II mesoionic xanthine acyclonucleosides.
First synthesis of 4H‐furo[3,2‐f]pyrrolo[1,2‐a][1,4]diazepines
Authors: Feng Xiao , Lancelot Jean‐Charles , Prunier Hervé , Rault Sylvain 
Published: March 2009

AbstractThe synthetic pathway leading to 4‐H‐furo[3,2‐f]pyrrolo[1,2‐a][1,4]diazepines is described in five steps starting from 2‐hydroxyketones via 2‐amino‐3‐furonitriles.
Synthesis and some transformations of 5‐benzotriazolyl‐3,4‐dihydropyrid‐2‐ones
Authors: Katritzky Alan R. , Shcherbakova Irina V. 
Published: March 2009

Abstract5‐(Benzotriazolyl)‐substituted 3,4‐dihydropyrid‐2‐ones were obtained by condensation of 4‐benzo‐triazolyl‐5‐phenyl(methyl)‐5‐oxopentanoic acids with benzyl or aryl amines. Dehydrogenation of 3,4‐dihydropyrid‐2‐ones resulted in 5‐benzotriazolyl‐substituted pyrid‐2‐ones and/or 5‐(phenylamino)pyrid‐2‐ones, products of nitrogen elimination from the benzotriazolyl substituent. In turn, 5‐benzotriazol‐1‐yl‐substituted pyrid‐2‐ones eliminated nitrogen under Graebe‐Ullmann conditions to give indolopyridones.
Nucleophilic substitutions of 2‐chloronaphtho[2,3‐b]furan‐4,9‐dione with amines
Authors: Koyanagi Jyunichi , Ogawa Masayuki , Yamamoto Katsumi , Nakayama Kouji , Tanaka Akira 
Published: March 2009

Abstract2‐Chloronaphtho[2,3‐b]furan‐4,9‐dione 4 was allowed to react with pyrrolidine to produce 2‐(1‐pyrrolidinyl)naphtho[2,3‐b]furan‐4,9‐dione 8 in 64% yield. In a similar manner, the reaction of 4 with cyclic amines (piperidine, morpholine, 4‐substituted piperazines, etc.) gave the desired compounds. 2‐Dimethylaminonaphtho[2,3‐b]furan‐4,9‐dione 20 and 2‐propylaminonaphtho[2,3‐b]furan‐4,9‐dione 23 were obtained from the reactions of 4 with amines in 67% and 48% yields, respectively. Furthermore, the reactions of 4 with acyclic amines (diethylamine, dipropylamine, isopropylamine, butylamine, etc.) gave the desired compound. Compound 4 was treated with sodium azide to give 2‐azidonaphtho[2,3‐b]furan‐4,9‐dione 28 in 42% yield. All these nucleophilic substitutions were carried out at room temperature. It was found that 4 showed high reactivity for amines. Unexpectedly, 2‐morpholinonaphtho[2,3‐b]furan‐4,9‐dione 13 was obtained from the reaction of 4 with 1‐morpholino‐1‐cyclohexene.