bluuebunny/crossref_metadata_2025_split huggingface dataset:
The synthesis and analgesic properties of new spiroisochromanyl acid derivatives synthesized from natural safrole
Authors: Cabral Lucio M. , Barreiro Eliezer J. 
Published: May 2009

AbstractWe describe in this paper the synthesis of a new spiro[2‐carboxycyclopentane‐1,1‐(6,7‐methylene‐dioxy)isochroman] and a spiro[2‐carboxycyclohexane‐1,1‐(6,7‐methylenedioxy)isochroman] acids 11 and 12, obtained from natural safrole (7), isolated from Sassafras oil. These derivatives were obtained in high overall yield using a synthetic route in which was observed brevity and appreciable diastereoselectivity in the intramolecular regioalkylation of the 6‐position of the aromatic system of the natural starting material, the key step of the synthetic route representing a variable in the well‐known Friedel‐Crafts reaction. The new acids, derivatives 11 and 12, were obtained in ca. 74% and 78% overall yield. They show a good analgesic profile in the pharmacological assay, the test in mice abdominal contortion.
Synthesis of small‐medium ring thioanhydrides
Authors: Kates Michael J. , Schauble J. Herman 
Published: May 2009

AbstractReaction of five‐membered ring anhydrides with sodium sulfide has previously been employed for synthesis of the corresponding thioanhydrides in low yields. Re‐examination of the stoichiometry reveals reaction of cyclic anhydride with sodium sulfide (2:1 respectively), affords the thioanhydride accompanied by the corresponding dicarboxylate in a 1:1 molar ratio. The mechanistic pathway for this reaction has also been elucidated. Optimization of reaction conditions has resulted in the synthesis of a variety of four to seven‐membered ring thioanhydrides in yields approaching theoretical.
Heterocycles from heterocycles. ‐ III[1]. 1,3,5‐trisubstituted hexahydro‐1,3,5‐triazines‐2‐ones from 1,3,5‐trisubstituted hexahydro‐1,3,5‐triazines and organic isocyanates
Authors: Verardo Giancarlo , Giumanini Angelo G. , Gorassini Fausto , Strazzolini Paolo , Benetollo Franco , Bombieri Gabriella 
Published: May 2009

Abstract1,3,5‐Triscubstituted hexahydro‐1,3,5‐trazin‐2‐ones 3 are easily obtained by the reaction of 1,3,5‐trisub‐stituted hexahydro‐1,3,5‐triazines1with organic isocyanates2. The reaction is believed to occur by the sequential addition to2of two molecules of the monomericN‐methyleneamines in thermal equilibrium with 1. Substituent scrambling at the operating temperature (120°) was negligible. The crystal structure of 1,3,5‐triphenylhexahydro‐1,3,5‐triazin‐2‐one(3a)has been determined by X‐ray diffraction methods.
Synthesis of spiro[4′,5′,10,11‐tetrahydro‐5H‐dibenzo[a,d]cyclohepten‐5‐yl‐2′(3′H)‐furans] as potential cytokine inhibitors
Authors: Ting Pauline C. , Solomon Daniel M. 
Published: May 2009

AbstractA synthesis of novel spiro[4′,5′,10,11‐tetrahydro‐5H‐dibenzo[a,d]cyclohepten‐5‐yl‐2′(3′H)‐furans] is described. The key reaction was formation of the tetrahydrofuran ring by cyclization of the diol 3 or the protected diol 10. These compounds were investigated as potential TNF‐α inhibitors.
Synthesis of 3‐amino‐2‐carbamoylthiophene and its reaction with cycloalkanones to form imines
Authors: Klemm L. H. , Wang Jun , Hawkins Lucas 
Published: May 2009

Abstract3‐Amino‐2‐carbamoylthiophene (2) was obtained in 75% yield by reaction of methyl 3‐aminothiophene‐2‐carboxylate with saturated aqueous ammonia containing ammonium chloride catalyst at room temperature over a period of 2,3 months, Treatment of 2 with cyclopentanone, cyclohexanone, and cycloheptanone in ethanol at pH 3.4 gave facile formation of 2‐carbamoyl‐3‐cycloalkylidenaminothiophenes in yields of 73%, 86%, and 60%, respectively. Infrared and 1H nmr spectra of these imines indicate that they occur in intramolecularly hydrogenbonded form, i.e. with chelate rings. Comparison is made with reported syntheses and reactions of 2 and its isosteric 2‐aminobenzamide.
Synthetic routes to indenopyridine analogues of morphactins
Authors: Braven J. , Hanson R. W. , Smith N. G. 
Published: May 2009

AbstractInvestigation of a number of synthetic routes to aza analogues of Morphaetins led to the synthesis of (RS)‐methyl 5H‐5‐hydroxyindeno[1,2‐b]pyridine‐5‐carboxylate (6e) and the corresponding caboxamide. 6f.
Preparation and spectroscopic characterization of bis(6,8‐dimethoxychroman‐5‐yl)methanes
Authors: Rama Nasim H. , Saeed A. , Bird C. W. , Cobb J. 
Published: May 2009

Abstract3,5‐Dimethoxyphenylalkan‐2‐ols react with diethoxymethane and boron trifluoride etherate, or aqueous formaldehyde and hydrochloric acid forming bis(6,8‐dimethoxychroman‐5‐yl)methanes.
Elucidation of the structure of quindolinone, a minor alkaloid of cryptolepis sanguinolenta: Submilligram 1H‐13c and 1H‐15N heteronuclear shift correlation experiments using micro inverse‐detection
Authors: Crouch Ronald C. , Davis Ann O. , Spitzer Timothy D. , Martin Gary E. , Sharaf Maged M. H. , Schiff Paul L. , Phoebe Charles H. , Tackie Albert N. 
Published: May 2009

AbstractElucidation of minor natural product structures has been significantly augmented by inverse‐detection; further improvement has been afforded by the development of micro inverse‐detection probes. We report here the elucidation of the structure of a new alkaloid, quindolinone (5H, 10H‐indolo[3,2‐b]quinolin‐11‐one), from the West African plant Cryptolepis sanguinolenta. All nmr data for this minor, preparative hplc‐isolated alkaloid, including 1H‐15N onebond heteronuclear shift correlation (HMQC) data, were recorded on an 800 μg sample of the alkaloid dissolved in 140 μl of 100% d6‐DMSO using a 400 MHz spectrometer.
Synthesis of new azonia‐helicenes with a quaternary nitrogen at the inner helix skeleton
Authors: Arai Sadao , Ishikura Masanori , Sato Kiyoshi , Yamagishi Takamichi 
Published: May 2009

AbstractThe 16c‐azonia[6]helicene salts, in which a carbon atom at the inner helix skeleton of [6]helicene is replaced by a quaternary nitrogen atom, have been synthesized by photo‐induced intramolecular quater‐nization of 2‐[2‐(1‐chloronaphthyl)vinyl]benzo[h]quinolines in acetonitrile.
Synthesis of 2,3,5,6‐tetrahydro‐4H‐1,4‐thiazin‐3‐one 1,1‐dioxides from methyl (styrylsulfonyl)acetate
Authors: Takahashi Masahiko , Yuda Junji 
Published: May 2009

AbstractMethyl (styrylsulfonyl)acetate (1) was shown to be a useful building block for the synthesis of 5‐phenyl‐2,3,5,6–4H‐tetrahydro‐1,4‐thiazin‐3‐one (2), its 4‐amino 3, and 4‐hydroxy 4 derivatives. Their 2‐spirocyclopropanes 9, 10, and 11, and 2,7‐diphenyl‐6,7‐dihydro‐8H‐pyrimido[5,4‐b][1,4]thiazinc 5,5‐dioxide (18) were also prepared from 1.
Synthesis of 5‐Amino‐9‐benzyl‐6‐formyl‐4‐methoxy‐2‐pivaloylamino‐7,8‐dihydropyrimido[4,5‐b]azepine. A potentially useful intermediate towards the synthesis of pyrimidoazepine based folic acid derivatives
Authors: Miller Michael L. , Ray Partha S. 
Published: May 2009

AbstractSynthesis of the title compound is described via an intramolecular 1,3‐dipolar cycloaddition reaction between the pyrimidine nitrile oxide 24 and an alkyne dipolarophile tethered to the 6‐position of the pyrimidine ring. The resulting isoxazolopyrimidoazepine cycloadduct 25 was treated with molybdenum hexacarbonyl to provide the titled enamino aldehyde 26.
Conformation and ortho steric effects in a series of 2‐(pyrazol‐1‐yl)quinolines
Authors: Singh Shiv P. , Kumar Dalip , Kumar Devinder , Martínez Ana , Elguero José 
Published: May 2009

AbstractNine 2‐(pyrazol‐1‐yl)‐4‐methylquinolines bearing substituents on the pyrazole 3‐ or 5‐positions (H, Me, Et, i‐Pr, t‐Bu) were regioselectively synthesized either using the direct condensation of 2‐chloro‐4‐methylquinoline and sodium salt of 3(5)‐substituted pyrazoles or by treatment of 2‐hydrazino‐4‐methylquinoline with an appropriate β‐ketoaldehyde. The 1H and 13C chemical shifts were discussed taking into account the preferred conformation about the C‐2‐N‐1′ bond as calculated by the AM1 Hamiltonian. It appears that 5‐ethyl and 5‐isopropyl substituted derivatives present short C‐H‐N‐1 interactions. Ortho steric effects appear to be responsible for these conformations.
Syntheses of folic acid models, 6‐(N‐acylarylamino)methyllumazines
Authors: Igarashi Mamoru , Kambe Tohru , Tada Masaru 
Published: May 2009

AbstractFolic acid models, 1,3‐dimethyl‐6‐(N‐acylarylamino)methyllumazines 9, were synthesized from 6‐bromomethyl‐1,3‐dimethyllumazine (6), which was derived from 5,6‐diamino‐1,3‐dimethyluracil (1) by the condensation with 1,3‐dihydroxyacetone, followed by bromination. The bromide 6 was also prepared by the cycloaddition between 3,6,8‐trioxo‐5,7‐dimethyl‐5,6,7,8‐tetrahydro‐3H‐pyrimido[5,4‐c][1,2,5]oxadiazine (4) and 1‐propenyl trimethylsilyl ether followed by bromination. The folic acid models 9 were also directly synthesized from the oxadiazine 4 and 3‐(N‐acylaryl)amino‐1‐propenyl trimethylsilyl ether 8 by cycloaddition.
Synthesis of 3‐substituted 4,1,2‐benzothiadiazine 4,4‐dioxides and 2 or 3‐substituted 1,4‐benzothiazine 1,1‐dioxides
Authors: Balbi A. , Sottofattori E. , Mazzei M. 
Published: May 2009

AbstractThe title compounds were prepared starting from the synthones 6 using two different synthetic approaches: 3‐substituted 1,4‐benzothiazine 1,1‐dioxides were synthesised by cyclisation with phosphorus oxychloride as the Vilsmeier reagent, while 4,1,2‐benzothiadiazine 4,4‐dioxides and 3‐substituted 1,4‐benzothiazine 1,1‐dioxides were obtained by direct diazotisation or by cyclisation with triethyl orthoformate.
Novel heterocycles derived from substituted aroylthioureas: Synthesis of 3, l‐benzothiazin‐4‐ones, thieno[3,2‐d][1,3]thiazin‐4‐ones and 1,2,4‐thiadiazolo[2,3‐a][3,1]benzothiazin‐5‐ones
Authors: Gütschow M. 
Published: May 2009

AbstractA series of heterocyclic aroylthioureas has been prepared and investigated as starting materials for ring closure reactions. The formation of several new 3,1‐benzothiazin‐4‐ones and thieno[3,2‐d][1,3]thiazin‐4‐ones (via cyclocondensation reactions) is reported. Oxidative cyclizations were carried out to produce methyl benzothiazole‐4‐carboxylates (via formation of an S‐C bond) as well as 1,2,4‐thiadiazolo‐[2,3‐a][3,1]benzothiazin‐5‐ones (via formation of an SN bond).
Synthesis and structural elucidation of pyrimido‐[1,2‐a]benzimidazoles and fused derivatives. i. dihydropyrimido[1,2‐a]benzimidazoles
Authors: El Ella Dalai Abou , Gößnitzer Edith , Wendelin Winfried 
Published: May 2009

AbstractThe condensation of 2‐benzimidazolarnine (4, BIA) with α,β‐unsaturated ketones 1 affords, according to Desenko, Orlov et al. [12,13], 1,4‐dihydropyrimido[1,2‐a]benzimidazoles (1,4‐DHPBI, 5I). However, the described ring closure reactions could a priori also yield isomeric 1,2‐DHPBI 8I or tautomers of DHPBIs 5I and 8I. An unequivocal proof for the postulated structures 5I was not presented. We prepared, as described [12,13], BIA‐chalcone‐ and BIA‐benzalacetone‐condensate X and Y, 5a, e or 8a, e, and additionally, their hydrochlorides. One and two dimensional high resolution nmr analyses showed that only isomers 5a, e and salts 5a, e·HCl were generated. In DMSO‐d6 these isomers exclusively exist as 1,4‐dihydro tautomers 5a, eI and 5a,eI·HCl. In trifluoroacetic acid 3,4‐dihydro tautomers 5a, eIII·CF3COOH besides of tautomers 5a, eI·CF3COOH (≈︁1:4) were ascertained. Action of ethanolic hydrochloric acid on base 5eI afforded, besides of 5eI·HCl as main product, a small amount of 2‐methyl‐4‐phenyltetrahydropyrim‐ido[1,2‐a]benzimidazol‐2‐ol hydrochloride 9e·HCl. The reaction of BIA 4 with α,β‐unsaturated ketones 1b‐d and f yielded 1,4‐DHPBI 5b‐dI and 5fI and their hydrochlorides, respectively. The stereochemistry of bases 5a, eI, of salts 5a‐eI·HCl and 5a, eIII·CF3COOH, and of addition product 9e·HCl was elucidated by nmr (stereoformulae in Figures 1–3 and Scheme 5). The accomplished nmr‐analyses are documented in detail and discussed.
Syntheses of various 5‐(3′‐substituted phenyl)uracils
Authors: Wellmar Ulf , Hömfeldt Anna‐Britta , Gronowitz Salo 
Published: May 2009

AbstractThe Suzuki Pd(0)‐catalysed coupling between arylboronic acids and aryl bromides or iodides in weakly alkaline medium has been used for the preparation of 5‐(3′‐chlorophenyl)‐, 5‐(3′‐iodophenyl)‐, 5‐(3′‐aminophenyl)‐, 5‐(3′‐azidophenyl)‐, 5‐(3′‐methylthiophenyl)‐ and 5‐(3′‐styryl)‐substituted 2,4‐di‐t‐butoxypyrimidines. In the coupling between 2,4 di‐t‐butoxy‐5‐pyrimidineboronic acid and the six different aryl halides that were used as coupling partners, only 1‐azido‐3‐bromobenzene did not give satisfactory yields, 18%. The other five aryl halides gave the desired 5‐(3′‐substituted phenyl)‐2,4‐di‐r‐butoxypyrimidines in 41–92% yield. Dealkylation of these five 5‐(3′‐substituted phenyl)‐2,4‐di‐t‐butoxypyrimidines in 2.5M hydrochloric acid gave the corresponding 5‐(bromoaryl)uracils in almost quantitative yields. 5‐(3′‐Azidophenyl)uracil was prepared in 43% yield directly from 5‐(3′‐aminophenyl)‐2,4‐di‐r‐butoxypyrimidine.
1H‐NMR study on the tautomer ratios between the hydrazone imine and diazenylenamine forms in 3‐(arylhydrazono)‐methyl‐2‐oxo‐1,2‐dihydroquinoxalines
Authors: Kurasawa Yoshihisa , Takano Akiko , Kato Kyoko , Takada Atsushi , Kim Ho Sik , Okamoto Yoshihisa 
Published: May 2009

AbstractThe o‐substituted 3‐(arylhydrazono)methyl‐2‐oxo‐1,2‐dihydroquinoxalines 1a‐c and 2a, c were synthesized to investigate the tautomeric behavior between the hydrazone imine A and diazenylenamine B forms in a series of mixed dimethyl sulfoxide/trifluoroacetic acid media. The chemical shifts of the hydrazone NH, N4‐H, hydrazone CH, and diazenyl CH protons for o‐, m‐, and p‐substituted 3‐(arylhydrazono)methyl‐2‐oxo‐1,2‐dihydroquinoxalines 1 and 2 synthesized so far are summarized in Tables 3 and 4, respectively, which are found to be useful for the specification of the proton signals due to the hydrazone imine form A (hydrazone NH, hydrazone CH) and diazenylenamine form B (N4‐H, diazenyl CH).
A facile synthesis of new β‐lactams
Authors: Lancelot J. C. , Saturnino C. , El‐Kashef H. , Perrine D. , Mahatsekake C. , Prunier H. , Robba M. 
Published: May 2009

AbstractSeveral new β‐lactams have been synthesized in good yields, via the cyclization of 3‐chloro‐N‐arylpropionamides in a mixture of N, N‐dimethylformamide and anhydrous sodium carbonate under a nitrogen atmosphere.
Synthesis of some pyrimido[4′,5′:4,5]thieno[2,3‐b]quinolines and related heterocycles
Authors: Hafez A. A. Abdel , El‐Dean A. Kamal , Hassan A. A. , El‐Kashef H. S. , Rault S. , Robba M. 
Published: May 2009

AbstractSeveral thieno[2,3‐b]quinolines 6a‐i have been synthesized. These compounds were used as key intermediates in the synthesis of oxazino[4′,5′:4,5]thieno[2,3‐b]quinoline 8, pyrimido[4′,5′:4,5]‐thieno[2,3‐b]quinolines 9–12, triazino[4′,5′:4,5]thieno[2,3‐b] quinolines 14 and imidazo[4′,5′:4,5]‐thieno[2,3‐b]quinolines 17.
O‐Alkylation of 3‐hydroxy‐1‐phenyl‐2‐pyrazolin‐5‐one
Authors: Molinari Aurora , Oliva Alfonso 
Published: May 2009

Abstract3‐Hydroxy‐1‐phenyl‐2‐pyrazolin‐5‐one 1 reacts with primary, secondary and allylic alcohols under catalytic acidic conditions and in the presence of 3 Å molecular sieves, to afford 3‐alkoxy‐1‐phenyl‐2‐pyrazolin‐5‐ones 3.
Azo dyes derived from Aminophenylbenzacridinones. VIII
Authors: Martínez Roberto , Arteaga Paulino , Mancera Claudia 
Published: May 2009

AbstractThe preparation of novel azo‐dyes from p‐aminophenylbenzacridinones is described. The structure of all the products was corroborated by ir, mass spectrometry and 1H‐nmr.
Spectroscopic studies of delavirdine mesylate (U‐90,152T) a bis(heteroaryl)piperazine (BHAP) HIV reverse transcriptase inhibitor
Authors: Farley Kathleen A. , Walker Gregory S. , Robins Russell H. , Kupstas‐Guido Jane E. , Duholke Wayne K. , Romero Donna L. , Morge Raymond A. , Meulman Paul A. , Chao Robert S. , Havens Jeffrey L. , Gage James R. , Lyster Mark A. , Fagerness Paul E. , Martin Gary E. 
Published: May 2009

AbstractComplete spectral assignments, including mass spectral fragmentation pathways, 1H and 13C resonances, and major infrared absorbance bands for the BHAP (bis(heteroaryl)piperazine) HIV reverse transcriptase inhibitor delavirdine are reported.
Haloacetylated enol ethers. 14 [6]. Reaction of β‐alkoxyvinyl trifluoromethyl ketones with N‐methylhydroxylamine
Authors: Martins Marcos A. P. , Flores Alex F. C. , Bastos Giovani P. , Zanatta Nilo , Bonacorso Helio G. 
Published: May 2009

AbstractThe reaction of a series of β‐methoxyvinyl trifluoromethyl ketones [CF3COC(R2)C(OMe)R1, where R1 = Me, ‐(CH2)3‐C3, ‐CH2)4‐C3, Ph and R2 = H, Me, ‐(CH2)3‐C4, ‐(CH2)4‐C4] with N‐methylhydroxylamine is reported. The regiochemistry of the reaction are explained by MO calculation data.
Synthesis of pyrido[3,2‐e]pyrrolo[2,1‐c][1,2,4]triazines from pyrido[3,2‐e][1,2,4]triazine derivatives
Authors: Savelli Francesco , Boido Alessandro , Ciarallo Giovanni 
Published: May 2009

AbstractIn carrying on our interest in heteropolycyclic structures with biological activities, we projected the preparation of compounds containing the pyrido[3,2‐e][1,2,4]triazine or pyrido[2,3‐b][1,4]triazepine systems. The established synthetic approach for the preparation of latter system led to the triazine derivatives 5a‐f while a new bicyclic triazepine structure 6 is accomplished with difficulty.In expanding the pyridotriazine structure, we obtained derivatives of a new tricyclic structure, 5‐substituted‐6a‐ethyloxycarbonyl‐5,6,6a,7‐tetrahydropyrido[2,3‐e]pyrrolo[2,1‐c][1,2,4]triazin‐9(8H)‐ones 8 in which the triazine ring is fused with a pyrrole nucleus.Compounds 5a‐f and 8a,b will be tested as potential CNS depressant, antiinflammatory, analgesic and antibacterial agents.
Investigation of the reaction of N‐substituted indolylborates: Palladium catalyzed cross‐coupling reactions and intramolecular alkyl migration reactions
Authors: Ishikura Minoru , Agata Isao , Katagiri Nobuya 
Published: May 2009

AbstractThe palladium catalyzed cross‐coupling reaction of indolylborates with various N‐protecting groups was investigated, where N‐Methyl, N‐methoxy, and N‐tert‐butoxycarbonyl groups were found to be useful. However, triethyl(1‐methoxymethylindol‐2‐yl)borate could not be used for this reaction. It was also found that the alkyl migration reaction of trialkyl(1‐methoxymethylindol‐2‐yl)borate produced 2‐alkyl‐1‐methyl‐indole accompanied by the unexpected reduction of 1‐methoxymethyl group to 1‐methyl group.
Synthesis, crystal structure and spectroscopic studies of 3‐hydrazono‐ and 3‐hydroxyiminoquinolin‐2‐ones
Authors: Mitsos Christos , Petrou John , Igglessi‐Markopoulou Olga , Markopoulos John 
Published: May 2009

Abstract3‐(Hydrazonoethyl)quinolinones 6–11, 13 and 3‐(hydroxyiminoethyl)quinolinones 14, 15 are prepared by a condensation reaction of 3‐acetylquinolinones 4, 5 with a variety of 1,2‐(bis)nucleophiles. The structures of the isolated compounds have been elucidated using 1H and 13C nmr spectroscopy. X‐ray diffraction studies of compound 14 were also performed.
Direct functionalization of 4,5‐dichloropyridazin‐6‐one
Authors: Chung Hyun‐A , Kweon Deok‐Heon , Kang Young‐Jin , Park Jung‐Won , Yoon Yong‐Jin 
Published: May 2009

AbstractDirect functionalization of 4,5‐dichloropyridazin‐6‐one with some nucleophiles in seven solvents gave regioselectively 5‐halo‐4‐substituted‐pyridazin‐6‐ones as main product. Reaction of 4,5‐dichloropyridazin‐6‐one with 2‐mercaptopyrimidine (2 equivalents) also afforded 4,5‐di(pyrimidin‐2‐ylsulfanyl)pyridazin‐6‐one as the main product.
Polycyclic fused phenanthridines: An alternative approach from benzotriazoles
Authors: Katritzky Alan R. , Du Weihong , Matsukawa Yasuhisa , Ghiviriga Ion , Denisenko Sergey N. 
Published: May 2009

AbstractWe describe an alternative approach to polycyclic phenanthridines (7) and some of their analogues using conditions much milder than those previously reported. The procedure includes the generation of a benzotriazole stabilized carbanion, oxidation of the resulting anion to a radical, and elimination of nitrogen followed by ring closure to produce phenanthridines.
Synthesis of 2‐aryl‐2,3‐dihydro‐4‐styrylpyrimidodiazepines in the reaction of 4,5,6‐triaminopyrimidine and 2,4,5,6‐tetraaminopyrimidine with diarylidenacetones
Authors: Insuasty Braulio , Insuasty Henry , Quiroga Jairo , Nogueras Manuel , Sánchez Adolfo , López M. Dolores 
Published: May 2009

AbstractNew 6‐amino and 6,8‐diamino‐2‐aryl‐2,3‐dihydro‐4‐styryl‐1H‐pyrimido[4,5‐b][1,4]diazepines were obtained in the reaction of 2,4,5,6‐tetraaminopyrimidine 1a and 4,5,6‐triaminopyrimidine 1b with one equivalent of the diaryli dene acetones 2 in absolute ethanol with acetic acid as the catalyst. Structure analysis of 6‐amino and 6,8‐diamino‐2‐aryl‐2,3‐dihydro‐4‐styryl‐1H‐pyrimido[4,5‐b][1,4]diazepines 3a‐i, determined by detailed nmr measurements, reveals a high regioselectivity of this reaction.
New indolium and quinolinium dyes sensitive to aqueous halide ions at physiological concentrations
Authors: Geddes Chris. D. , Douglas Peter , Moore Christopher P. , Wear Trevor J. , Egerton Peter L. 
Published: May 2009

AbstractTwelve new highly fluorescent dyes have been produced by the reaction of two heterocyclic nitrogen bases with 8‐bromooctanoic acid, 11‐bromoundecanoic acid and 15‐bromopentadecanoic acid. The bromide counter ions of the first six dyes have been replaced with the tetraphenylborate ion. Unlike the bases themselves, the quaternary salts are water soluble and have fluorescence characteristics independent of pH in the pH range 7–11. Both the fluorescence intensity and fluorescence lifetime of dyes 1–12 are reduced in the presence of aqueous halide ions allowing halide concentrations to be determined accurately at physiological levels. All the dyes have been characterised in terms of steady state fluorescence spectra and steady‐state Stern‐Volmer analysis.
Cycloadditions of adamantanethione S‐methylide to CC multiple bonds
Authors: Mloston Grzegorz , Huisgen Rolf , Huber Helmut , Stephenson David S. 
Published: May 2009

AbstractAdamantanethione S‐methylide (12) is a nucleophilic 1,3‐dipole which easily combines with electrophilic acetylenic and ethylenic bonds affording dihydrothiophene and thiolane derivatives, usually in high yields. The S‐methylide 12, generated by extrusion of nitrogen from the 2,5‐dihydro‐1,3,4‐thiadiazole 11, can not be isolated, but is intercepted in situ by dipolarophiles; otherwise, 12 furnishes irreversibly the spirothiirane 13. The 1H nmr spectra and mass spectra establish the regiochemistry for the adducts of methyl propiolate, acrylonitrile, methyl acrylate, benzylidenemalononitrile and methyl α‐cyanocinnamate. The 1,3‐dipole does not react with common alkenes; the highly strained trans‐cyclooctene gives rise to a cycloadduct.
An unexpected result in the condensation of 2‐amino‐6‐bromopyridine with ethyl 4‐chloroacetoacetate: Four dihalo‐substituted pyrido[1,2‐a]pyrimidin‐4‐ones as reaction products
Authors: Ferrarini Pier Luigi , Mori Claudio , Mori Filippo , Saccomanni Giuseppe , Barontini Silvia , Macchia Marco , Barili Pier Luigi , Hamdan Mahmoud 
Published: May 2009

AbstractWe report here the condensation of 2‐amino‐6‐bromopyridine with ethyl 4‐chloroacetoacetate in polyphosphoric acid. In this reaction, a mixture of the four possible dihalo‐4H‐pyrido[1,2‐a]pyrimidin‐4‐ones 1–4 was obtained.
X‐ray crystallographic and NMR structural studies of trans‐2,3‐dichloro‐5‐ethyl‐2,3‐dihydrothieno[2 3‐b]pyridine syn‐1‐oxide reactions of thiophene rings with hypochlorite reagents
Authors: Klemm Leroy H. , Weakley Timothy J. R. , Yoon Myungok 
Published: May 2009

AbstractX‐ray analysis of a crystalline product obtained by treatment of 5‐ethylthieno[2,3‐b]pyridine with excess acidified hypochlorite establishes its stereochemistry as trans‐2,3‐dichloro‐5‐ethyl‐2,3‐dihydrothieno‐[2,3‐b]pyridine syn‐1‐oxide (5), wherein the pyridine ring is planar and the dihydrothiophene ring is non‐planar with a C2‐S‐C7a angle of 86.6°. The trans geometry is corroborated by a proton‐proton coupling constant J2,3 of 6.8 Hz. Comparison of 1H and 13C nmr data for 5 with analogous crystalline 2,3‐dichloro‐1‐oxide addenda isolated in the isosteric benzo[b]thiophene and thieno[2,3‐b]pyridine parent systems indicates that some proposed stereochemical assignments are questionable.