bluuebunny/crossref_metadata_2025_split huggingface dataset:
Free radical 4‐nitrophenylation of thieno[2,3‐b]pyridine. Part 1: General experimental procedure and prediction of isomeric ratios of products
Authors: Klemm Leroy H. , Miller Kristi 
Published: March 2009

AbstractThieno[2,3‐b]pyridine (1) was warmed at 45 ± 7° with diazotized 4‐nitroaniline (2) (molar ratio 1:2 = 3.6:1) in buffered (sodium acetate‐acetic acid) aqueous solution until gas evolution ceased. The reaction mixture was separated into these fractions: (a) water‐soluble (discarded), (b) acetone‐soluble (tars), (c) ether‐soluble, and (d) ether‐ and chloroform‐soluble, but acetone‐insoluble (rust‐colored solids, Y, 12% yield as 4‐nitrophenyl‐1 isomers, 3). Fractional evaporative distillations of (b) and (c) gave recovered 1 (69%) and yellow‐red sublimates (Z, 20% yield as 3). Y and Z were handled separately for isolation and identification of isomers [2]. Three general methods for predicting the isomeric ratios of 3 which one should obtain are presented, viz. (1) an amalgamation of reported free‐radical phenylation results for quinoline and benzo[b]thiophene, (2) calculations of Frontier Radical Densities for positions 2‐6 only, and (3) Molecular Orbital calculations for electron densities and superdelocalizabilities for free‐radical attack at positions 1‐7, as modified by a proposed rearrangement of the attacking group from the heteroatomic N and S positions to adjacent alpha positions.
Pyranopyrazoles III synthesis of 1H‐pyrano[2,3‐c]pyrazol‐4‐ones
Authors: Khan Misbahul Ain , Ellis Gwynn Pennant , Pagotto Mario Celso 
Published: March 2009

AbstractVarious derivatives of title ring system were synthesized by Claisen condensation of 4 acetyl‐5 ‐hydroxy‐pyrazoles with appropriate esters, followed by acid‐catalyzed ring closure.
Attempted synthesis of ethyl 3,4‐dihydro‐2H‐1,4‐benzoxazine‐3‐carboxylate and 3‐acetate derivatives
Authors: Mayer Stanislas , Arrault Axelle , Guillaumet GÉRald , Mérour Jean‐Yves 
Published: March 2009

AbstractEthyl 3,4‐dihydro‐2H‐1,4‐benzoxazine‐3‐carboxylate derivatives 2 were obtained and isolated in low yields from the condensation of 2‐aminophenol and ethyl 2,3‐dibromopropanoate. They can be obtained by hydrogenation of ethyl 2H‐1,4‐benzoxazine‐3‐carboxylate in satisfactory yield. Using 2‐iminophenol did not direct the condensation with ethyl 2,3‐dibromopropanoate towards 2 but was fruitfull for the preparation of ethyl 2‐(4‐benzyl‐3,4‐dihydro‐2H‐1,4‐benzoxazin‐3‐yl)acetate from ethyl bromocrotonate.
Study of the reactions of 3‐acetoacetyl‐7‐methyl‐2H,5H‐pyrano[4,3‐b]pyran‐2,5‐dione with aromatic amines
Authors: Boutemeur‐Kheddis Baya , Hamdi Maamar , Sellier Nicole , Silva Artur M. S. 
Published: March 2009

AbstractThe reactions of 3‐acetoacetyl‐7‐methyl‐2H,5H‐pyrano[4,3‐b]pyran‐2,5‐dione with aromatic amines afforded 3‐(arylaminomethylene)‐6‐methylpyran‐2,4‐dione. Our results allowed the correction of the structures reported in the literature for the products of these reactions.
Transformations of schiff bases derived from quinoline‐8‐carbaldehyde. Synthesis of C‐8 substituted quinolines
Authors: Ocal Nüket , Yolaçan ÇIgdem , Kaban ŞEniz , Leonor Vargas M. , Kouznetsov Vladimir 
Published: March 2009

AbstractThe Schiff bases derived from quinoline‐8‐carbaldehyde and substituted aromatic amines were used in the synthesis of C‐8 substituted quinolines. 3‐Aryl‐2‐(8‐quinolinyl)‐4‐thiazolidinones were prepared from obtained aldimines by means of the cyclocondensation of mercapto acids. A series of 4‐N‐arylamino‐4‐(8‐quinolinyl)‐1‐butenes was synthesized through the addition of the Grignard reagent (allylmagnesium bromide) to the double bond C=N of these aldimines. The structure of the prepared compounds was established on the basis of their elemental analyses and spectral data.
On triazoles XLII . A new convenient method for the N‐alkylation of highly insoluble cyclic amides
Authors: Berecz GÁBor , Reiter JÓZsef 
Published: March 2009

AbstractA simple N‐alkylation method of highly insoluble cyclic amides based on the high solubility of their easily isolable tetraalkylammonium and tetraalkylphosphonium salts was elaborated. The method has a rather wide scope, it is not influenced by the identity of the different rings attached to the 1,2,4‐triazolo[1,5‐a]‐pyrimidinone moiety of isomers 1 and 2, nor the presence of the triazole substituents. It proceeds smoothly without any unwanted by‐products, at relatively low temperatures, and is not sensitive to moisture. The method allows an easy isolation of all possible N‐alkylated derivatives 3, 7, and 8. Spectral analysis of isomers 3, 7, and 8 showed that our previous results concerning the formation of 3 type N‐alkylated derivatives as main products of the N‐alkylations as well as the tautomeric structure of the non‐alkylated isomers 1 and 2 is correct. However, it also showed that the isolation of a single N‐alkylated isomer 3 and its comparison with the corresponding non‐alkylated derivative to prove its tautomeric structure may lead to mistakes.
Synthesis of a new series of purine derivatives and their anti‐cyclin‐dependent kinase activities
Authors: Legraverend Michel , Ludwig Odile , Leclerc Sophie , Meijer Laurent 
Published: March 2009

AbstractThe synthesis of new purine derivatives designed to inhibit cell cycle regulating cyclin‐dependent kinases (CDKs), is reported. These compounds, related to olomoucine and roscovitine, are characterised by the presence of apyrrolidine methanol substituent at C‐2 and a variety of ortho, meta and/or para substituents on the C‐6 arylamino group.
Synthesis of 2‐amino‐1,4‐dihydro‐4‐quinolinones and diaminomethylene meldrum's acids derivatives as potential potassium channel openers
Authors: Erb Béanéadicte , Rigo Benoît , Pirotte Bernard , Couturier Daniel 
Published: March 2009

AbstractStarting from 5‐bismethylthiomethylene Meldrum's acid, the synthesis of 5‐diaminomethylene Meldrum's acids and 2‐aminoquinolone derivatives, structurally related to potassium channels openers pinacidil and diazoxide, is described.
On the photochemical dimerization of some 5‐substituted 2‐styryl‐4‐pyrones. The effect of 5‐hydroxy‐/ 5‐methoxy‐substitution
Authors: Stiplošek Zdenka , Šindler‐Kulyk Marija , Jakopčić KreŠImir , Višnjevac Aleksandar , KojiĆ‐ProdiĆ Biserka 
Published: March 2009

AbstractIrradiation of styryl‐4‐pyrones 1a‐1d or 2a‐2e (6‐9 × 10−3 M, methanol solution) with filtered (RAYONET photochemical reactor, 300 nm) or unfiltered uv‐light (high‐pressure mercury arc lamp) under aerobic conditions led mainly to dimeric products. Parent 5‐hydroxy‐substituted compounds 1a‐1d yielded exclusively “half‐cage” dimers 3a‐d characteristic for 4‐pyrone dimerization. 5‐Methoxy‐analogues 2a‐2e behave like typical stilbene structures and the mixture of tetrasubstituted cyclobutanes 4 and 5 accompanied with minor amount of phenanthrene‐like compound 6 were the only isolable products of the irradiation. The structure elucidation of products is based on spectral data obtained from MS, IR, 1H NMR and 13C NMR spectra applying COSY, APT, HETCOR, HMBC and NOESY techniques.
A convenient one‐pot synthesis and antimicrobial activity of pyrimido[1,2‐b][1,2,4,5]tetrazines
Authors: Shawali Ahmad S. , Abdallah Magda A. , Zayed Mohie M. 
Published: March 2009

AbstractThe synthesis of the hitherto unreported 3‐amino‐2,3‐dihydro‐6‐phenyl‐2‐thioxo‐4(1H)‐pyrimidine 2 and 3‐amino‐2‐methylthio‐6‐phenyl‐4(3H)‐pyrimidinone 3 is described. Reactions of hydrazonoyl halides 1 with either 2 or 3 afforded 6H‐pyrimido[1,2‐b][1,2,4,5]tetrazin‐6‐ones 6. The latter products were screened for their antifungal and antibacterial properties. The mechanism of the studied reactions is discussed.
Synthesis of 6‐(2‐hydroxybenzoyl)pyrazolo[1,5‐a]pyrimidines by reaction of 5‐amino‐1h‐pyrazoles and 3‐formylchromone
Authors: Quiroga Jairo , Mejía Diana , Insuasty Braulio , Abonía Rodrigo , Nogueras Manuel , Sánchez Adolfo , Cobo Justo , Low J. N. 
Published: March 2009

AbstractReaction of 3‐formylchromone (1) with 5‐amino‐1H‐pyrazoles (2) in ethanol, afforded 6‐(2‐hydroxy‐benzoyl)pyrazolo[1,5‐a]pyrimidines (3a‐g) in good yields. The structures and the regiospecificity of the reaction were established by nmr measurements and X‐ray analysis, in which soft intermolecular hydrogen‐bonded networks were found.
Synthesis and spectral properties of 11‐[(o‐; and p‐substituted)‐phenyl]‐8‐[(o‐; m‐;p‐methoxy)phenylthio]‐3,3‐dimethyl‐2,3,4,5,10,11‐hexahydro‐1h‐dibenzo[b,e][1,4]diazepin‐1‐ones
Authors: Cortéas Eduardo Cortéas , Sanabria Ana María Hernández , Mellado Olivia García 
Published: March 2009

AbstractThe preparation of twelve novel 2,3,4,5,10,11‐hexahydro‐1H‐dibenzo[b,e] [1,4]diazepin‐l‐ones which have potentially useful pharmacological properties; by condensation and cyclization between 3‐{[4‐(o‐; m‐; p‐methoxy)phenylthio]‐1,2‐phenylenediamine}‐5,5‐dimethyl‐2‐cyclohexenone with (o‐; and p‐substi‐tuted)benzaldehyde. The structure of all final products were corroborated by ir, 1H‐nmr, 13C‐nmr and ms.
Photocyclization reactions. Part 8. Synthesis of 2‐quinolone, quinoline and coumarin derivatives using trans‐cis isomerization by photoreaction
Authors: Horaguchi Takaaki , Hosokawa Nobuyuki , Tanemura Kiyoshi , Suzuki Tsuneo 
Published: March 2009

Abstract2‐Quinolone 2, quinoline 3, coumarin (2H‐1‐benzopyran‐2‐one) 5, and 2H‐1‐benzopyran hemiacetal 6 were synthesized by photocyclization reaction of traans‐o‐aminocinnamoyl derivatives trans‐1 and trans‐o‐hydroxycinnamoyl derivatives trans‐4. The reaction proceeds through trans‐cis isomerization followed by intramolecular cyclization.
Synthesis and characterization of the novel l‐(substituted phenoxy/phenyl)‐2‐phospholene and phospholane 1‐oxide derivatives
Authors: Reddy Vallum Krishna , Onogawa Jun‐Ichi , Rao Lakonda Nagaprasada , Oshikawa Tatsuo , Takahashi Masaki , Yamashita Mitsuji 
Published: March 2009

AbstractThe synthesis of the novel 1‐(substituted phenoxy/phenyl)‐2‐phospholene and phospholane 1‐oxide derivatives, which are analogs of sugars having a phosphorus atom in place of the ring oxygen of normal sugars, is described. All of the synthesized derivatives are structurally characterized by multi nuclear NMR, mass, and IR spectral data, elemental and X‐ray crystallographic analyses.
Studies on pyrrolidinones: Some attempts to improve the anticancer properties of methyl n‐(3,4,4′,5‐tetramethoxybenzhydryl)pyroglutamate (HEI 81)
Authors: Bourry Anne , Rigo Benoît , Sanz Géarard , Couturier Daniel 
Published: March 2009

AbstractThe synthesis of esters, amides, pyrrolidinone and succinimide analogs of a new inhibitor of tubulin polymerization, methyl N‐(3,4,4′,5‐tetramethoxybenzhydryl)pyroglutamate (HEI 81) was studied.
Synthesis of nitrogen‐containing heterocycles 10. Reaction of 2‐amino‐1h‐imidazole derivatives with ethoxymethylene compounds
Authors: Miyamoto Yoshiko 
Published: March 2009

AbstractThe direct annelation reaction of 4‐substituted 2‐amino‐l‐benzylideneamino‐1H‐imidazoles (1) or 2‐amino‐1‐isopropylideneamino‐1H‐imidazole (8) with ethoxymethylenemalononitrile (I) gave successfully bicyclic imidazo[1,2‐a]pyrimidine compounds 2 and 9 in high yields. The reactions of other ethoxymethylene compounds of lower reactivity, i.e., ethyl ethoxymethylenecyanoacetate (II) and diethyl ethoxymethylenemalonate (III), with 2‐amino‐1H‐imidazoles under similar conditions afforded the corresponding enamines 3, 4 and 10, which, upon heating in the presence of an acid or a base, could readily be cyclized to form imidazopyrimidines except for 1‐isopropylideneamino compound 10. In general, the 3‐phenyl compounds (3b and 4b) did not cyclize to the type 2 compound resulting in a full recovery of the starting enamines.
Synthesis of thieno[2,3‐b][1,5]benzoxazepine derivatives
Authors: Kohara Toshiyuki , Tanaka Hiroshi , Kimura Koreichi , Horiuchi Hideki , Seio Kohji , Arita Masafumi , Fujimoto Tetsuya , Yamamoto Iwao 
Published: March 2009

AbstractA new series of 4‐(4‐methylpiperazin‐1‐yl)thieno[2,3‐b][1,5]benzoxazepines 1a‐k has been synthesized from 4‐bromo‐2‐methylthiophene 6 or ethyl 2‐amino‐4,5‐dimethyl‐3‐thiophencarboxylate 10. Preparation of the key intermediate thieno[2,3‐b][1,5]benzoxazepine‐4(5H)‐ones 4a‐i, 4k were carried out by treatment of 2‐bromo‐N‐(2‐hydroxyphenyl)‐3‐thiophencarboxamides 5a‐i, 5k with potassium carbonate in DMSO. Compounds 1 are thienoanalogues of loxapine, a potent antipsychotic drug. Of these compounds, the neu‐roleptic activity of 2‐methyl‐4‐(4‐methylpiperazin‐l‐yl)thieno[2,3‐b][1,5]benzoxazepine 1a (R1, R3=H, R2=CH3) demonstrated potent antipsychotic activity.
Synthesis and photochromism of photochromic spiro compounds having a reactive pendant group
Authors: Zhang Peng , Meng Jiben , Li Xiaoliu , Wang Yongmei , Matsuura Teruo 
Published: March 2009

AbstractThe photochromic spiropyrans and spirooxazines having a reactive pendant group, including carboxyl, halide, succinimidyl ester and isothiocyanate, were synthesized. Their photochromic behaviors in solution and solid state were studied.
Arenesulfonylheterocycles (I): Synthesis and reactions of 2‐benzenesulfonyl‐4,5‐dichloropyridazin‐3‐ones with amines
Authors: Kweon Deok‐Heon , Kim Ho‐Kyun , Kim Jeum‐Jong , Chung Hyun A. , Yoon Yong‐Jin , Lee Woo Song , Kim Sung‐Kyu 
Published: March 2009

AbstractThe direct sulfonylation of 4,5‐dichloropyridazin‐3‐ones with some benzenesulfonyl chlorides in the presence of base in tetrahydrofuran gave only the corresponding N‐sulfonylated product. The reaction of 2‐benzenesulfonyl‐4,5‐dichloropyridazin‐3‐ones with some aliphatic amines under neutral conditions afforded 5‐alkylamino‐2‐benzenesulfonyl‐4‐chloropyridazin‐3‐ones and/or the corresponding N‐alkyl‐benzenesulfonamides.
Pictet‐spengler synthesis of pyrazole‐fused β‐carbolines
Authors: Fasfous Ismail I. , El‐Abadelah Mustafa M. , Sabri Salim S. 
Published: March 2009

AbstractThe synthesis of new pyrazolo[4,3‐c]β‐carbolines (8a,b) is achieved by condensation of the appropriate aldehyde with 3‐(4‐amino‐1,3‐dimethylpyrazol‐5‐yl)indole (4) under Pictet‐Spengler reaction conditions. Regioselective cyclization occurred at the usual indole C‐2 position as evidenced from the 1H‐and 13C nmr spectra of 8a,b which lack the pyrrolic H‐2 signal, present in 4 (δ 7.26, 1H, d, Jch‐NH = 2‐5 Hz).
New trans/cis tetrahydroisoquinolines. 1. trans‐2‐benzyl‐3‐(l‐methyl‐1h‐pyrrol‐2‐yl)‐4‐substituted‐1,2,3,4‐tetrahydroisoquinolin‐1‐ones and corresponding tetrahydroisoquinolines
Authors: Kozekov I. D. , Koleva R. I. , Palamareva M. D. 
Published: March 2009

AbstractThe reaction of homophthalic anhydride and N‐(1‐methyl‐1H‐pyrrol‐2‐yl‐methylidene)‐benzylamine in boiling benzene afforded as a main product the expected substituted trans‐1,2,3,4‐tetrahydroisoquinoline‐4‐carboxylic acid 5. The carboxylic group of 5 was transformed in four steps into cyclic amino‐methyl groups yielding numerous new tetrahydroisoquinolinones 11a‐j incorporating a given fragment of pharmacological interest. Reduction of 11a‐j was studied.
Synthesis and spectroscopic properties of 15n‐labelled 1,2,4‐thiadiazoles
Authors: Pavlik James W. , Changtong Chutchawin , Tantayanon Supawan 
Published: March 2009

Abstract5‐Phenyl‐1,2,4‐thiadiazole‐4‐15N and 3‐methyl‐5‐phenyl‐1,2,4‐thiadiazole‐4‐15N were synthesized from commercially available benazmide‐15N. The mass spectra and the 1H, 13C, and 15N‐nmr spectra of these compounds, which show various long‐range heteronuclear coupling with the 15N‐nucleus, are discussed.
The ionization constants of 2‐substituted 4,6‐diamino‐s‐triazines: The applicability to the hammett and taft equations
Authors: Tashiro Tatsuo 
Published: March 2009

AbstractThe ionization (or basicity) constants (pKb) were determined for many 2‐substituted 4,6‐diamino‐s‐tri‐azines (I) by means of the electrometric titration. I includes 2‐alkoxy or aryloxy‐(Ia), 2‐alkyl‐ or 2‐aryl‐(Ib), and 2‐alkylamino‐ or 2‐arylamino‐4,6‐diamino‐s‐triazines (Ic). For the series with the same alkyl or aryl group, the order of the basicity was found to be Ic < Ib < Ia.A study was made of relationships between the pKb, values of I, and the substituent constants, σp, σm, σp+, σm+, σpO, σmo, σI, σn, and σ*. The Hammett relationships were observed between the pKa values of I, and the substituent constants σm, (or the combination ones, [0.97σm + 0.03σp] as well as another [0.77σI + 0.23σR]). The Taft relationships were also found between the pKa values of Ia, Ib, and Ic and the constants σ*, respectively. Furthermore, in the case of Ic a linear relationship was observed between the pKa values and Σσ8.
Multi‐step synthesis of benzopyranones via a key step involving reaction of the intermediate compound with phenyltrimethylammonium tribromide
Authors: Javed T. , Kahlon S. S. 
Published: March 2009

AbstractBase catalysed condensation of a substituted 2‐hydroxyacetophenone with acetic anhydride and sodium acetate followed by cyclization of the intermediate with acid gave substituted 3‐acetyl‐2‐methyl‐4H‐1‐benzopyran‐4‐ones. These were then brominated with phenyltrimethylammonium tribromide (PTT) to yield the desired 3‐(2‐bromoacetyl)benzopyran‐4‐ones. The latter compound on treatment with primary and secondary aryl or alkyl amines, gave the corresponding benzopyran‐4‐one derivatives.
Iodo cyclofunctionalization of 2,4‐dialkenyl‐1,3‐dicarbonyl compounds: Synthesis of substituted 3‐(2‐furylidene)‐2‐furanones
Authors: Valduga Claudete J. , Stefani Hélio A. , Petragnani Nicola 
Published: March 2009

AbstractA facile method for the synthesis of substituted 3‐(2‐furylidene)‐2‐furanones has been developed using cyclofunctionalization reactions of 2,4‐dialkenyl‐1,3‐dicarbonyl compounds and iodine as electrophile in the presence of Na2CO3, in refluxing chloroform. Compounds 4 are obtained in modest to good yields and their structural identification was established by 1H NMR, 1H COSY, 13C NMR and 1H‐13C COSY. A mechanism has been proposed to rationalize the formation of the ylidene furanone.
Synthesis and biological testing of 3‐phenyloctahydro‐pyrimido[1,2‐a]‐s‐triazine derivatives
Authors: Lucry Line , Enoma Ferdinand , Estour François , MÉnager Sabine , Lafont Olivier , Oulyadi Hassan 
Published: March 2009

AbstractA series of 46 3‐phenyloctahydropyrimido[1,2‐a]‐s–triazine derivatives were synthesized. This synthesis was performedviaiminodimethylation of dialkylated 2‐aminopyrimidinedione synthons by substituted primary arylamines.In vitropharmacological evaluation of these compounds is reported. One of them exhibited antifungal activity againstMicrosporum canis(10−65010−5mol/L), and another showed affinity for serotoninergic 5‐HT1Aand 5‐HT2breceptors (10−85010−7mol/L).
Synthesis of [1,4]benzodioxino[2,3‐c and 2,3‐d]pyridazinones
Authors: Chung Hyun‐A , Kim Jeum‐Jong , Cho Su‐Dong , Lee Sang‐Gyeong , Yoon Yong‐Jin , Kim Sung‐Kyu 
Published: March 2009

AbstractReaction of chloropyridazin‐3‐one 1, 5 and 10 with catechol in the presence of potassium carbonate gave the corresponding [1,4]benzodioxino[2,3‐e and/or 2,3‐d]pyridazinones 2, 7, 8 and 11.
Synthesis and electrochemical studies of tetrathiafulvalene derivatives (TTFs) as redox active ligands
Authors: Sarhan Abd El‐Wareth A. O. , Murakami Makoto , Izumi Taeko 
Published: March 2009

AbstractA simple route for synthesis of new tetrathiafulvalene dimethyl ester (TTF‐DME) is reported. The tetrathifulvalene dimethylester (TTF‐DME) has been prepared by introducing an ester coordination function as a bifunctional new donor. The redox behavior of the TTF‐DME was investigated in comparison to the well‐known dibenzotetrathiafulvene (DB‐TTF) by cyclic voltammetry. A two‐electron redox behavior was observed as a two waves.
On triazoles XLVI. Synthesis of 1,3a,5,6,10c‐pentaazaacephenanthrylenes
Authors: Berecz Gabor , Párkányi László , Reiter József , Kálmán Alajos 
Published: March 2009

AbstractA novel route to the synthesis of 6,7,8,9‐tetrahydro‐[1,2,4]triazolo[5,l‐b]quinazoline derivatives 4 through 5 and 6 was elaborated. During the synthesis of derivatives 6 novel type tetracyclic 2,3,7,8,9,10‐hexahydro‐1,3a,5,6,10c‐pentaazaacephenanthrylenes 9 were formed as by‐products. Their structure was proved by spec‐troscopic methods and by X‐ray diffraction spectra. There were also elaborated direct synthetic routes to derivatives 9. Unexpectedly, the S‐alkyl groups of derivatives 9 could be easily replaced by different amines, which is contrary to all our previous results. Possible explanations to this enhanced reactivity are given.
Regioselective symmetrical bromination of protected 2,2′‐biimidazole
Authors: Sanchez‐Garcia David , Borros Salvador , Nonell Santi , Borrell Jose I. , Colominas Carles , Teixido Jordi 
Published: March 2009

AbstractTreatment of the benzyl and (trimethylsilylethoxymethyl) SEM protected 2,2′‐biimidazoles, 2a and 2b, with 2 equivalents of N‐bromosuccinimide (NBS) allows obtaining the 5,5′‐dibromo and 4,4′‐dibromo substituted biimidazoles, 3a and 5b respectively. The use of 4 equivalents of NBS, followed by treatment of the corresponding tetrabromoderivatives 4a and 5b with butyl lithium (BuLi), yields the 4,4′‐dibromoderiva‐tives 5a (G=Bn) and 5b (G=SEM).
Synthesis of dihydrofuro[2,3‐b]pyridines by the reaction of 2‐amino‐4,5‐dihydro‐3‐furancarbonitriles with α,β‐unsaturated carbonyl compounds
Authors: Maruoka Hiroshi , Yamazaki Motoyoshi , Tomioka Yukihiko 
Published: March 2009

AbstractThe reactions of 2‐amino‐4,5‐dihydro‐3‐furancarbonitriles 1a‐d with α,β‐unsaturated carbonyl compounds in the presence of sodium ethoxide (0.1 equivalent) gave the corresponding Michael adducts 2a‐d, 3a‐d and 4a‐d. Compounds 2a‐d and 3a‐c reacted with sodium alkoxide (1 equivalent) to yield the corresponding 7a‐alkoxyhexahydrofuro[2,3‐b]pyridines 5a‐d, 6a‐d, 7a‐c and 8a‐c. Treatment of 5a‐d, 6a‐d, 7a‐c and 8a‐c with potassium tert‐butoxide produced the corresponding dihydrofuro[2,3‐b]pyridines 9a‐d and 10a‐c. The reaction of 4a‐c with sodium ethoxide (1 equivalent) afforded the corresponding dihydro‐furo[2,3‐b]pyridines 11a‐c.
Stereochemistry and opioid receptor affinity of 2,4‐dipyridine‐3,7‐diazabicyclo[3.3.1]nonanones ‐ influence of the substituent in position N7
Authors: Cambareri A. , Zlotos D. P. , Holzgrabe U. , Englberger W. , Haurand M. 
Published: March 2009

AbstractThe stereochemistry the 2,4‐di‐arene substituted 3,7‐diazabicyclo[3.3.1]nonan‐9‐one 1,5‐dicarboxylate skeleton was found to be regulated by the kind of substituents attached to the arene rings as well as to the nitrogens N3 and N7. Conformational isomers, i.e., chair/chair, boat/chair and chair/boat, in addition to cis/trans conflgurational isomerism with respect to the arene rings were reported. Since the analgesic potency of the diazabicyclononanones, which is related to their affinity toward the κ‐opioid receptor, is governed by the stereochemistry of the molecules, the influence of the substituents at nitrogen N7 was studied herein. The various differently N7 substituted diazabicyclononanones were found to crystallise in a highly symmetrical chair/chair conformation. However, beside HZ2 none of the compounds exhibits high affinity to the κ receptor. In contrast, some compounds with affinity to the μ receptor could be identified. In addition, the N7‐(4‐carboxybenzyl) substituted compound was found to have affinity to the δ receptor in the submi‐cromolar range of concentration.
An efficient synthesis of a class of novel N‐Alkyl‐N‐aryl‐4‐hydroxy‐1‐methyl‐2‐oxo‐1,2‐dihydro‐3‐quinolinecarbothioamides
Authors: Spears Glen W. , Tsuji Kiyoshi , Tojo Takashi , Nishimura Hiroaki , Ogino Takashi 
Published: March 2009

AbstractThe novel title compounds have been prepared in high yield by an optimized amide coupling followed by a Dieckmann cyclization. Additionally, this new route is amenable to preparative scale synthesis.
Synthesis of N4‐substituted[1,3,4]oxadiazinan‐2‐ones derived from norephedrine
Authors: Casper David M. , Nora George P. , Blackburn Jennifer R. , Bentley Jeromy T. , Taylor Deanna C. , Hitchcock Shawn R. 
Published: March 2009

Abstract[1,3,4]‐Oxadiazinan‐2‐ones bearing substitution at the N4‐position have been synthesized from norephedrine in good yield via N‐alkylation, nitrosation, reduction and cyclization.