bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemistry of condensed thiophenes. V. Sulfonation and sulfonyl bridging of m‐terphenyl. Conversion to sulfonamides
Authors: Klemm L. H. , Lane Will , Hall Eliot 
Published: March 2009

AbstractReaction of m‐terphenyl with 20% oleum at 100° gives both disulfonation and double sulfonyl bridging to yield benzo[1]thieno[2,3‐b]dibenzothiophene‐3,9‐disulfonic acid 5,5,7,7‐tetraoxide, isolated as the disodium salt (24%) and convertible (via the disulfonyl chloride) to the bis‐sulfonanilide (44%) and the bis‐N‐butylsulfonamide (40%). Analogously, reaction of m‐terphenyl with chlorosulfonic acid at 100° gives disulfonation plus only single sulfonyl bridging to produce 2‐(4‐chlorosulfonyl)‐7‐chlorosulfonyldibenzothiophene 5,5‐dioxide (80%), convertible to the corresponding bis‐sulfonanilide (63%) and the bis‐N‐butylsulfonamide (45%).
Metallation of diazines. III. New synthesis of analogues of trimethoprim and of bacimethrin
Authors: Ple N. , Turck A. , Fiquet E. , Queguiner G. 
Published: March 2009

Abstract4‐Chloro‐2,6‐dimethoxypyrimidine was lithiated by lithium 2,2,6,6‐tetramethylpiperidide. The resulting lithio derivative was submitted to reaction with carbonyl derivatives, iodine and trimethyltin chloride. Synthesis of analogues of trimethoprim and of bacimetrin are reported.
Nouvelle synthèse des composés polysubstitués d'esters de l'acide pyrrolecarboxylique‐3 par réarrangement d'époxy‐1,2 pyrrolidines
Authors: Dehnel André , Kanabus‐Kaminska Jolanta M. 
Published: March 2009

AbstractSous Taction des acides (en particulier fluorure d'hydrogène/pyridine) les éthoxycarbonyl‐3 oxa‐6 aza‐1 bicyclo[3,1,0]hexanes polysubstitués 1 se transforment de façon stéréospécifique en éthoxycarbonyl‐3 pyrroles polysubstitués 3. Les substrate 1 spiranniques conduisent dans ces conditions aux produits polycycliques.
Directed regiospecificity of 1,3‐dipolar cycloaddition of 2‐diazopropane to 4‐ and 5‐substituted pyridazin‐3(2H)‐ones
Authors: Jelen Boris , Štimac Anton , Stanovnik Branko , Tišler Miha 
Published: March 2009

Abstract6‐Methoxy‐2‐methylpyridazin‐3(2H)‐one (1) gave with 2‐diazopropane (8) a mixture of 3H‐pyrazolo[3,4‐d]‐pyridazin‐4(5H)‐one derivative 12, as the main product, and ‐7(6H)‐one derivative 10, as the minor product. On the other hand, 4‐substituted pyridazin‐3(2H)‐ones 2, 3, and 4 gave 3H‐pyrazolo[3,4‐d]pyridazin‐7(6H)‐one 10, exclusively, while 5‐substituted pyridazin‐3(2H)‐ones 5, 6, and 7 produced only the isomeric 3H‐pyrazolo[3,4‐H]pyridazin‐4(5H)‐one 12. The 5‐phenylsulfonyl derivative 13 gave with 8 by elimination of a molecule of nitrogen, followed by rearrangement, 1,2‐diazepine derivative 15 and with an excess of 8 3H‐pyrazolo[3,4‐d][1,2]diazepine derivative 16. 1,2‐Dimethylpyridazine‐3,6‐(1H,2H)‐dione and its derivatives 18 and 19 produced 3H‐pyrazolo[3,4‐d]pyridazine‐4,7(5H,6H)‐dione derivative 23, while from 17 and 1‐diazoindane (24) the spiro compound 27 was obtained. The 1,2‐dihydro and 3a,7a‐dihydro intermediates 21 and 25 were isolated.
Synthesis of various 5‐substituted 2′‐deoxy‐3′‐5′‐di‐O‐acetyluridines
Authors: Peters Dan , Hörnfeldt Anna‐Britta , Gronowitz Salo , Johansson Nils Gunnar 
Published: March 2009

AbstractThe Pd(0)‐catalyzed coupling reaction of β‐5‐iodo‐2′‐deoxy‐3′,5′‐di‐O‐acetyluridine with various heteroaryltrimethylstannyl compounds gave the corresponding β‐5‐heteroaryl‐2′‐deoxy‐3′,5′‐di‐O‐acetyluridines in moderate yields. This direct coupling approach for nucleosides represented an interesting alternative to the 5‐heteroaryl functionalization of pyrimidines followed by the Hilbert‐Johnson glycosylation reaction which often yields mixtures of the α and β anomers.
Pyrazoles. 5. Novel pyrazole analogues of flavanone, flavone and flavane
Authors: Heinisch Gottfried , Hollub Christian , Holzer Wolfgang 
Published: March 2009

AbstractThe synthesis of the new pyrano[2,3‐c]pyrazole derivatives 4, 5, and 7 starting from (E)‐(1,3‐dimethyl‐5‐hydroxy‐4‐pyrazolyl)‐3‐phenyl‐2‐propen‐1‐one (2) is reported.
Synthesis and antibacterial activities of novel oxazine and thiazine ring‐fused tricyclic quinolonecarboxylic acids: 10‐(Alicyclic amino)‐9‐fluoro‐7‐oxo‐7H‐pyrido[1,2,3‐de][1,4]benzoxazine‐6‐carboxylic acids and the corresponding 1‐thia congeners
Authors: Okada Tetsuo , Tsuji Teruji , Tsushima Tadahiko , Ezumi Kiyoshi , Yoshida Tadashi , Matsuura Shinzo 
Published: March 2009

AbstractSeveral analogs 4 and 5 of Ofloxacin (1) which contain the oxazine and thiazine rings fused with a quinolone carboxylic acid moiety, respectively, were prepared and their in vitro and in vivo antibacterial activities were compared with those of 1 and its previously prepared 3‐exo‐methylene analogs 2 and 3. Unlike 1, 2, and 3, analogs 4 and 5 possess an antiaromatic oxazine and thiazine moiety and show markedly lower antibacterial activities. Alteration of their C‐10 amino‐substituent groups from piperazine to azetidine significantly improved the in vitro antibacterial activities, particularly in the case of the thiazine derivative 5, but not the in vivo ones. The antibacterial activities of these three types of tricyclic quinolonecarboxylic acids are briefly discussed on the basis of the molecular properties revealed by molecular orbital calculation. The molecular dipole moment was suggested to be one possible factor controlling the binding affinity of these compounds with DNA gyrase.
Synthesis of condensed quinoxalines
Authors: Sabnis R. W. , Rangnekar D. W. 
Published: March 2009

AbstractA novel efficient synthesis of fluorescent, fused quinoxalines was achieved. 6‐Triazolylthiazolo[4,5‐b]quinoxalines were synthesized by the diazotisation of 6‐amino‐2‐methylthiazolo[4,5‐b]quinoxaline and coupling with selected aromatic amines followed by air oxidation. Diazotised aryl amines were coupled with 6‐amino‐2‐methylthiazolo[4,5‐d]quinoxaline followed by subsequent air oxidation afforded 1,2,3‐triazolo[5,4‐f]quinoxalino[2,3‐d]thiazoles. 6‐Amino‐2‐methylthiazolo[4,5‐b]quinoxaline was condensed with conjugated enol ethers followed by cyclization in dowtherm resulted in thiazolo[4,5‐b]quinoxalino[6,5‐b]pyridine.
3‐Substituted 2‐pyridinecarbaldoximes
Authors: Kao Bo‐Chan , Doshi Haresh , Reyes‐Rivera Hector , Titus Donald D. , Yin Mali , Dalton David R. 
Published: March 2009

AbstractA series of 2‐pyridinecarbaldoximes and salts derived from them by methylation of the pyridine nitrogen, all of which are substituted at the 3‐position with carbon (i.e., derivatives of nicotinic acid and its homologues) or oxygen, have been prepared.
Products from furans. VII. A General Route for the Synthesis of α‐(1,2‐cis) and β‐(1,2‐trans) Glycoconjugates via 1‐O‐Acyl and 1‐O‐Ethoxycarbonyl‐2‐azido‐2,3‐dideoxyglycopyranosides
Authors: Georgiadis Minas P. , Couladouros Elias A. 
Published: March 2009

AbstractA methodology for the synthesis of 2,3,6‐trideoxy‐ and 2,3‐dideoxy‐2‐aminoglycosides is presented. 2,3‐Dideoxyhex‐2‐enopyranos‐4‐uloses (named also as 2H‐pyran‐3(6H)‐ones) were used for the synthesis of 1‐O‐acetyl, 1‐O‐ethyloxycarbonyl and 1‐S‐phenyl‐2,3,6‐trideoxy‐(or 2,3‐dideoxy)‐2‐azidoglycopyranosyl donors. Glycosidation of the above thio‐ethers with a variety of alcohols in the presence of N‐bromosuccinimide as activator yielded predominantly α‐glycosides, while acetates afforded β‐glycosides when TMSOTf was used as a promoter. The coupling of carbonates using tin tetrachloride or TMSOTf proved to be the most successful procedure, yielding the β‐glycoside as the predominant product. Thus, glycoconjugates of aminosugars, steroids and aminoacids have been synthesized.
Further studies on the synthesis of quinazolines from 2‐fluorobenzonitriles
Authors: Hynes John B. , Tomažič Alenka , Parrish Christie A. , Fetzer Oliver S. 
Published: March 2009

AbstractRecently, we reported that appropriately substituted 2‐fluorobenzonitriles undergo cyclization with guanidine carbonate to afford 2,4‐diaminoquinazolines usually in good to excellent yield. This paper describes the preparation of a variety of new 2,4‐diaminoquinazolines substituted at positions five or seven. In addition, the reactions of selected 2‐fluorobenzonitriles with formamidine acetate or acetamidine acetate were examined. The results obtained demonstrate that the analogous 4‐amino‐ and 2‐methyl‐4‐aminoquinazolines can be prepared by this approach but that the yields are considerably lower than when guanidine carbonate is employed as the cyclization reagent.
Synthesis of 1,3,4‐thiadiazin‐2‐one and 1,3,4‐selenadiazin‐2‐one derivatives as new cardiotonic drugs
Authors: Morvan Marcel , Nadler Guy , Zimmermann Richard G. 
Published: March 2009

AbstractThe synthesis of the new heterocycle 1,3,4‐selenadiazin‐2‐one is described, based on the preparation of the analogue heterocycle 1,3,4‐thiadiazin‐2‐one. The related cyclization between an α‐haloketone and a thiocarbazate cannot readily be employed within the selenium series. Therefore a new route was developed based upon a diazotization/hydrolysis sequence of the related 2‐amino‐1,3,4‐selenadiazine.
13C and 1H NMR analysis of the nitration products of 2‐amino‐4‐oxo‐(3H)‐5‐trifluoromethylquinazoline and 2‐amino‐4‐oxo‐(3H)‐5‐fluoroquinazoline
Authors: Singh Shyam K. , Fetzer Oliver S. , Hynes John B. , Williams Thomas C. 
Published: March 2009

AbstractNitration of 2‐amino‐4‐oxo‐(3H)‐5‐trifluoromethylquinazoline is shown to occur exclusively at C6 as determined from an analysis of long range 1H and 19F scalar couplings to ring carbons. Nitration of 2‐amino‐4‐oxo‐(3H)‐5‐fluoroquinazoline is found to occur both at C6 and C8 as evident from an analysis of the 19F and 1H couplings of the ring protons.
Simple synthetic routes to 5‐(3,6‐dihydro‐2‐oxo‐2H‐1,3,4‐thiadiazin‐5‐yl)‐1H‐indole‐2,3‐diones and their Derivatives
Authors: Delimoge Isabelle , Morvan Marcel , Nadler Guy , Zimmermann Richard G. 
Published: March 2009

AbstractTwo different synthetic routes to 5‐(3,6‐dihydro‐2‐oxo‐2H‐1,3,4‐thiadiazin‐5‐yl)‐1H‐indole‐2,3‐diones are described. The reaction sequences represent a facile entry into these series of isatin derivatives.
Synthesis of 5‐chloropyrazoles by chlorodediazoniation with sulfur dioxide
Authors: Yamamoto Susumu , Morimoto Katsushi , Sato Toshiaki 
Published: March 2009

AbstractA facile synthesis of 5‐chloropyrazoles 4a‐e from 5‐aminopyrazoles 2a‐e via diazotization followed by chlorodediazoniation is described. A new application of sulfur dioxide as a catalyst was demonstrated to be the best for the chlorodediazoniation of diazonium chlorides 3a‐e.
On triazoles. XXV. The reaction of methyl (5‐amino‐3‐Q‐1H‐1,2,4‐triazolyl)dithiocarbonates with amines
Authors: Barkóczy József , Reiter József 
Published: March 2009

AbstractDifferent “functionalised” triazolylthioamides 3 and ‐thioureas 4 were synthesised. The ring closure of the ω‐hydroxyalkylthioamides 3/2–5 led to the corresponding 2‐thiazoline 5/2–4 and 5,6‐dihydro‐4H‐1,3‐thiazine 5/5 derivatives, respectively. Unexpectedly, the ring closure of the corresponding 2,2‐dimethoxyethyl derivative 3/18 led depending on the reaction conditions to a thiazole derivative 6 or to its 1,2,4‐triazolo[3,4‐b]‐1,3,5‐triazepin‐5(9H)‐thione isomer 7 representing a novel ring system. To corroborate its structure 7 was methylated to the corresponding S‐methyl derivative 8. Spectroscopical evidence is given for the structure of derivatives 3–8 obtained.
Synthesis of 5‐cyclopropyluracil and 5‐cyclopropylcytosine by the Pd(0)‐catalyzed coupling reaction
Authors: Peters Dan , Hörnfeldt Anna‐Britta , Gronowitz Salo 
Published: March 2009

Abstract5‐Cyclopropyluracil and cyclopropylcytosine were prepared by the Pd(0)‐catalyzed coupling reaction of 5‐bromo‐2,4‐di(trimethylsilyloxy)pyrimidine and 5‐bromo‐2,4‐O,N‐bis‐trimethylsilylcytosine with tributylstan‐nylcyclopropane. The reactions also gave dehalogenated pyrimidine bases as by‐products. Attempts to use 2,4‐O,N‐bis‐trimethylsilyl‐5‐iodocytosine as the halide gave complete dehalogenation.
Oxidation of 1,3,4,6‐tetrakis(alkylthio)thieno[3,4‐c]‐thiophenes with iodine in the presence of aniline
Authors: Tsubouchi Akira , Kitamura Chitoshi , Matsumura Noboru , Inoue Hiroo 
Published: March 2009

Abstract1,3,4,6‐Tetrakis(alkylthio)thieno[3,4‐c]thiophenes were oxidized by iodine in the presence of aniline in dry benzene to give 1,4,6‐tris(alkylthio)thieno[3,4‐c]thiophen‐3(1H)‐imines in high yields through the intermediary formation of their cation radicals.
Linked porphyrin systems
Authors: Fleischer Everly B. , Shachter Amy M. 
Published: March 2009

AbstractPorphyrin monomers, 5‐(monopyridyl)‐10,15,20‐(triphenyl)porphyrin (1), 5,10‐(dipyridyl)‐15,20‐(diphenyl)‐porphyrin (2), and 5,15‐(dipyridyl)‐10,20‐{diphenyl)porphyrin (3), were linked by hydrocarbon chains to form a series of dimers, trimers and polymers. The 5‐(monopyridyl)‐10,15,20‐(triphenyl)porphyrin monomers were linked by 2, 4, 6, 8 and 10 carbon chains through the alkylation of the pyridine nitrogens using the appropriate diiodoalkane to form positively charged linked dimers 4–8. A trimer 12 was synthesized from two 5‐(monopyridyl)‐10,15,20‐(triphenyl)porphyrin and one 5,10‐(dipyridyl)‐15,20‐(diphenyl)porphyrin linked by a six carbon chain. Hydrocarbon linked (5,10‐(dipyridyl)‐15,20‐(diphenyl)porphyrin)n (13) and (5,15‐(dipyridyl)‐10,20‐(diphenyl)porphyrin)n (14) were also prepared.
Heterocycles from amino acids. A novel synthetic approach for imidazo[1,5‐a]pyridines and imidazo[1,5‐a]quinolines
Authors: Kolar Patrik , Petrič Andrej , Tišler Miha , Felluga Fulvia 
Published: March 2009

AbstractFrom the corresponding heterocyclic amino acids 2 and 9a the heterocyclic systems imidazo[1,5‐a]pyridine (3) and imidazo[1,5‐a]quinoline (10) are easily accessible. From compound 7 the tricyclic system 11 was prepared and from compound 17a a pyridyl‐1,2,4‐triazinone (18) could be obtained.
17O NMR spectroscopy: Intramolecular hydrogen bonding in hydroxypyridine carboxy esters
Authors: Boykin David W. , Kumar Arvind 
Published: March 2009

AbstractNatural abundance 17O nmr chemical shift data for 8 aryl esters and 10 pyridine carboxy esters, including 6 ortho‐hydroxy esters, recorded in acetomitrile at 75° are reported. The carbonyl group 17O nmr chemical shift data for methyl 2‐, 3‐ and 4‐pyridinecarboxylate are correlated with σ+ constants. The hydrogen bonding component (ΔδHB) to the ester carbonyl 17O nmr chemical shift for the intramolecular hydrogen bonded ortho‐hydroxy systems are 9.8 ppm, 13.6 ppm and 4.3 ppm for benzoates, 2‐pyridinecarboxylates and 4‐pyridinecarboxylates, respectively. The relationships of the ester ΔδHB values to other hydrogen bond acceptor ΔδHB values are discussed.
Analogues of the antibiotic puromycin as potential prodrugs of 3′‐amino‐3′‐deoxythymidine
Authors: Wengel Jesper , Motawia Mohammed S. , Pedersen Erik B. , Nielsen Carsten M. 
Published: March 2009

AbstractCondensation of L‐ and D‐3′‐amino‐2′,3′‐dideoxynucleosides 2–5 with N‐BOC‐protected aminoacids 6 and 13 using dicyclohexylcarbodiimide and N‐hydroxysuccinimide in DMF is reported to give the N‐BOC‐protected acylamino aminonucleosides 7–9 and 14 in 51–81% yield. After deprotection using trifluoroacetic acid the corresponding unprotected new analogues of puromucin 10–12 and 15 were obtained in 43–56% yield. These compounds did not show any significant antiviral activity using HIV (stain HTLV‐III B)‐infected MT‐4 cells as target system.
First transformations of pyrano[3,4‐b]indol‐3‐ones to salvadoricine and 2,3‐diacylindoles
Authors: Pindur Ulf , Erfanian‐Abdoust H. 
Published: March 2009

AbstractThe readily available methylated pyrano[3,4‐b]indol‐3‐ones 1a and 1b were hydrolyzed to furnish the 2‐acetylindol‐3‐alkanoic acids 2 and 4. Compound 2 was easily transformed selectively to 2‐acetyl‐3‐methylindole (3, salvadoricine). Substrate 1b reacts with molecular oxygen from the air only in the presence of a catalyst to give 2,3‐diacetylindole (5) while 1a reacts with nitrosobenzene via a proposed Diels‐Alder step to yield 2‐acetylindole‐3‐carbaldehyde (6). The latter product can also be obtained in low yield from the reaction of 1a with molecular oxygen from the air.
Amidrazones. 14. The formation of 1,1‐disubstituted hydrazines from the base‐promoted hydrolysis of 1,l‐disubstituted‐3‐amino‐4,5‐dihydro‐1H‐pyrazolium halides: Mechanistic considerations
Authors: Smith Richard F. , Dennis Lisa A. , Ryan William J. , Rodriguez George , Brophy Keith A. 
Published: March 2009

AbstractThree mechanistic pathways are considered for the hydroxide‐promoted conversion of 1,1‐disubstituted‐3‐amino‐4,5‐dihydro‐1H‐pyrazolium halides 1 to 1,1‐disubstituted hydrazines, ammonia and sodium 3‐hydroxypropanoate. Evidence presented in this paper supports a hydrolysis mechanism c that is initiated by hydroxide ion addition to the 3‐position of 1 to form a tetrahedral intermediate 7.
One‐pot synthesis of 4‐acylimino‐2‐aminothieno[2,3‐d][1,3]‐thiazines from 2‐thioureidothiophene‐3‐carbonitriles
Authors: Gütschow Michael , Leistner Siegfried , Pink Maren 
Published: March 2009

AbstractA new one‐pot synthesis of 4‐acylimino‐2‐aminothieno[2,3‐d][1,3]thiazines 4 and 5, respectively, from 2‐thioureidothiophene‐3‐carbonitriles 1, acetic, propionic anhydride, respectively, and concentrated sulfuric acid is reported. The structure of 4a is confirmed by X‐ray structure analysis.
Carbazoledioxazines having long alkyl groups. 3. Syntheses and properties of halogen free carbazoledioxazines
Authors: Ikeda Masaaki , Kitahara Kiyoshi , Nishi Hisao 
Published: March 2009

AbstractLong chain derivatives of halogen free carbazoledioxazine which is a typical organic pigment with a linear type structure (5,15‐dialkyl‐5,15‐dihydrodiindolo[3,2‐b:3′,2′‐m]triphenodioxazines) and an angular type structure (5,15‐dialkyl‐7,17‐dialkoxy‐5,15‐dihydrodiindolo[2,3‐c:2′,3′‐n]triphenodioxazines) were newly synthesized. Their structures were confirmed by 1H‐nmr, ms and elemental analysis. The thermal, spectroscopical and electrochemical properties were investigated by means of DSC, uv‐vis and cyclic voltammetry.
Synthesis of novel 1,3‐oxazino[6,5‐b]indole‐2,4‐(3H,9H)‐dione and 2H‐1,3,5‐oxadiazino[3,2‐a]indole‐2,4‐(3H)‐dione from oxindoles
Authors: Gallaschun Randall J. , Schnur Rodney C. 
Published: March 2009

AbstractTwo novel tricyclic ring systems were designed as serine protease inhibitors and synthesized from oxindoles; the first series, 1,3‐oxazino[6,5‐b]indole‐2,4‐(3H,9H)‐diones, were prepared from 2,3‐dihydro‐2‐oxo‐(1H)‐indole‐3‐carboxamides and phosgene in tetrahydrofuran with triethylamine. The second, a 2H‐1,3,5‐oxadiazino[3,2‐a]indole‐2,4‐(3H)‐dione was made using a similar cyclization on 2,3‐dihydro‐2‐oxo‐N‐phenyl‐(1H)‐indole‐1‐carboxamide.
Addition‐rearrangement reactions of 5‐amino‐3‐oxo‐Δ4–1,2,4‐thiadiazolines
Authors: L'Abbé Gerrit , Albrecht Ernestine 
Published: March 2009

AbstractBond‐switching rearrangement via hypervalent sulfur occurs during the reactions of 5‐anilino‐2‐benzyl‐3‐oxo‐Δ4–1,2,4‐thiadiazoline 5 with electrophilic nitriles, isothiocyanates, carbon disulfide and ketenes, yielding the products 6 and 7. In contrast, N,N'‐ditolylcarbodiimide reacts with 5 to give the normal addition product 8, which rearranges only partially to 9 in several solvents (chloroform, acetonitrile and dimethyl sulfoxide). The equilibrium position depends on the temperature, favoring 9 at higher temperatures.
The synthesis of a new polycyclic heterocyclic ring system: Pyrimido[5,6,1‐d,e]acridine
Authors: Antonini Ippolito , Martelli Sante 
Published: March 2009

AbstractThe synthesis of a new heterocylic ring system is reported. The condensation of 9,10‐dihydro‐9‐oxo‐4‐acridine carboxamide (7) with diethoxymethyl acetate gave pyrimido[5,6,1‐d,e]acridine‐3,7‐dione (8). The amide 7 reacts with ethyl chloroformate to afford 2H‐pyrimido[5,6,1‐d,e]acridine‐1,3,7‐trione (9).
Heterotricyclic systems. Part I. Synthesis of new dipyridopyrazines
Authors: Savelli Francesco , Boido Alessandro 
Published: March 2009

AbstractPursuing our previous research on azaquinoxalinones (1,2‐dihydropyrido[2,3‐b]/[3,4‐b]pyrazinones) we prepared, through a reductive cyclization of N‐(3′‐nitropyridin‐2′‐yl)piperidine‐2‐carboxylic acids 3a‐c, a set of derivatives of a new tricyclic structure, 7,8,9,10‐tetrahydro‐5H‐dipyrido[1,2‐a:3′,2′‐e]pyrazin‐6(6aH)‐ones 4a‐c. Starting from these compounds we obtained substituted amides 5a‐c and, from 4a, the amidines 6a‐c. In the synthesis of 6, a dehydrogenation reaction occurred giving rise to 7. The compounds 9 and 10, characterized by a different ring‐fusion between the pyridine and pyrazine rings, were synthesized in a similar manner.
Stereoselective synthesis of new spirobenzodihydropyrancyclohexanes
Authors: Bédoui Ahmed , Mayrargue Joëlle , Moskowitz Henri , Thal Claude 
Published: March 2009

AbstractA stereoselective synthesis of unknown spirobenzodihydropyrancyclohexanes is described starting from arylcyclohexenes alkylated and cyclized via a coumarin intermediate and leading to new amino derivatives which are rigid analogs of dopamine.
Synthesis and 1H NMR spectra of some 1‐aryl‐2,5‐pyrrolidinediones
Authors: Hubbard John L. , Carl John M. , Anderson Gary D. , Rankin Gary O. 
Published: March 2009

AbstractThree 1‐aryl‐2,5 pyrrolidinediones, two of which are novel, were prepared by reaction of the requisite primary aromatic amines with succinic anhydride, followed by treatment with acetic anhydride. The 1H nmr spectra for the derivatives in which aryl is 1‐naphthyl and 1‐anthracenyl exhibit 32‐line multiplets for the four aliphatic hydrogens, indicating that all four are in different environments. Examination of molecular models demonstrates that the pyrrolidinedione and aryl ring systems cannot be coplanar and that rotation about the nitrogen‐aryl bond is restricted. Molecular mechanics calculations reveal that a dihedral angle of 50–65° for the two ring systems results in the minimum steric interaction energy.
Reactions of salicylaldehyde with some conjugated olefins
Authors: Yamaguchi Seiji , Saitoh Takenao , Kamiumezawa Megumi , Enomoto Hiroko , Kawase Yoshiyuki 
Published: March 2009

AbstractSome condensation reactions of salicylaldehyde with various conjugated olefins, 1a, 1b, 1c, 2a, 2b, 2c, and 3, were studied. In the condensations with 1a, 1b, and 1c gave 2,2‐dimethyl‐2H‐chromene derivatives via “3–2 cyclization”, while the condensations with 2a, 2b, 2c, and 3 gave 2‐methyl‐2H‐chromen‐2‐yl)acetic acid derivatives via “3–4 cyclization”.
Preparation of novel tricyclic ring systems containing the pyridazinone ring
Authors: Yamasaki Tetsuo , Kawaminami Eiji , Uchimura Fumi , Okamoto Yoshinari , Okawara Tadashi , Furukawa Mitsuru 
Published: March 2009

AbstractNovel tricyclic ring systems, irmdazo[3,4‐d]pyridazino[4,5‐b][1,4]thiazines 3, imidazo[2,1‐b]pyridazino[4,5‐e][1,3,4]thiadiazines 15 and 18 were prepared by the reaction of 5‐amino‐4‐chloropyridazin‐3(2H)‐ones 1 and 5(4)‐(1‐methylhydrazino)‐4(5)‐chloropyridazin‐3(2H)‐ones 13 (16) with isothiocyanates 2 and 7.
Methyl 2‐benzoylamino‐3‐dimethylamonopropenoate in the synthesis of heterocyclic systems. A simple synthesis of amino derivatives of isomeric naphthopyranones and naphthodipyranones
Authors: Ornik Brina , Stanovnik Branko , Tišler Miha 
Published: March 2009

AbstractA simple synthesis of the amino derivatives of 3H‐naphtho[2,1‐b]pyran‐3‐one 5b‐d, 8,11, and 20, 2H‐naphtho[1,2‐b]pyran‐2‐one 14 and 19, 2H,6H‐naphtho[1,2‐b:3,4‐b']dipyran‐2,6‐dione 9, 2H,11H‐naphtho[2,1‐b:3,4‐b']dipyran‐2,11‐dione 12, and 3H,9H‐naphtho[1,2‐b:5,6‐b']dipyran‐3,9‐dione 15 from the corresponding monohydroxynaphthalenes 2c,d, dihydroxynaphthalenes 2b, 7, 10, and 13, and tetralones 16 and 17 with methyl 2‐benzoylamino‐3‐dimethylaminopropenoate (3) in acetic acid is described.