bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation and some reactions of 3,5:8,10‐di‐1,3‐benzo[8](3,4)‐1,2,5‐thiadiazolocyclophane
Authors: Hatta Taizo , Mataka Shuntaro , Tashiro Masashi , Suzuki Hiroshi , Numano Katsutoshi 
Published: March 2009

AbstractTitled 1,2,5‐thiadiazolometacyclophane 1 was prepared via thia[2.3]cyclophane 5 which was obtained by the reaction of di(bromomethyl) 2 with sodium sulfide under phase‐transfer‐catalyzed conditions. Cyclophane 1 gave the corresponding pyrene derivatives by the oxidative transannular reaction in the reaction with brominating reagent. Reduction of 1 with lithium aluminum hydride followed by acetylation with acetic anhydride gave a 4:l‐mixture of cis‐ and trans‐diamide 11 and 12 with a trace amount of cyclophane‐ring‐cleaved product 13. On the other hand, 13 was obtained as a major product in the reduction with metal sodium and diisobutylaluminum hydride.
Reactions of 2,3‐bishydroxyimino‐1,2,3,4‐tetrahydro‐quinoxalines and 2,3‐bishydroxyimino‐2,3‐dihydro‐4H‐1,4‐benzoxazines with ethyl chloroformate
Authors: Varella Evangelia A. , Nicolaides Demetrios N. 
Published: March 2009

AbstractBishydroxyiminoquinoxalines 3a‐b react with ethyl chloroformate 4 to afford the furazano[3,4‐b]quinoxalines 5a‐b. Bishydroxyiminobenzoxazines 6a‐c on treatment with 4 are converted into the fused oxadiazolones 7a‐c and 8a‐c along with the bisethoxycarbonyloxyimino‐derivatives 9a‐c. From the reactions of 4 with the oxanilide dioximes 12a‐c compounds 13a‐c and 14a‐b are obtained.
Saturated heterocycles. 176 Synthesis and steric structure of quaternary azeto[2,1‐a]isoquinoline stereoisomers
Authors: Bernáth Gábor , Fölöp Ferenc , Árva Judit , Kóbor Jenö , Sohár Pál 
Published: March 2009

AbstractStarting from 1‐substituted azeto[2,1‐a]isoquinoline diastereomers, a number of quaternary salts were prepared. The reactions leading to the quaternary salts were stereospecific, independently of the configuration at C‐1, resulting in diastereomers. The steric structures of the new compounds were proved by nmr spectroscopy.
1,3‐Dipolar cycloadditions of diazoalkanes to pyridazine derivatives. Thermal 1,5‐sigmatropic rearrangement of methyl groups in 3,3‐dimethyl‐3H‐pyrazolo[3,4‐d]pyridazine derivatives
Authors: Stanovnik Branko , Jelen Boris , Štimac Anton , Tišler Miha 
Published: March 2009

AbstractThermal 1,5‐sigmatropic rearrangements of one of the methyl group attached at position 3 of 3,3‐dimethyl‐3H‐pyrazolo[3,4‐d]pyridazin‐4(5H)‐ones 1–3 taking place either in a clock‐wise or anti‐clockwise direction gave N2‐methylated products 4–6 and C3a‐methylated products 7–9. The ‐7(6)‐one derivative 10 and ‐4,7(5H,6H)‐dione derivative 12 gave only N2‐methylated products 11 and 13 respectively, and 1,2‐dihydro derivative 14 produced after elimination of methane, 15.
Electrophilic benzylation of 2‐aminopyridine ring
Authors: Kowalski Piotr 
Published: March 2009

AbstractIn the reaction of 2‐aminopyridine and its 3‐ or 5‐methyl derivatives with benzyl chloride used in a molar ratio of 1:2, benzylation of 2‐aminopyridine ring has been stated that 2‐amino‐3‐ or 5‐benzylpyridines c as the major products were obtained. Formation of c type compounds took place in the decomposition of 2‐benzylamino‐3‐ or 5‐benzylpyridines b obtained in the reaction of the 2‐benzylaminopyridines a, excess benzyl chloride was used. Production of the b and c compounds, where the benzyl substituent occupied position 3 or 5 in 2‐aminopyridine supported the electrophilic mechanism of the reaction (radical reaction was excluded). In the case of 2‐aminopyridine and its 3‐methyl derivative bis‐(2‐amino‐5‐pyridyl)phenylmethanes d were formed as the by‐products.
Conjugated macrocycles related to the porphyrins. Part 2. Further synthetic and spectroscopic studies on difuryl analogs of the oxophlorins
Authors: Lash Timothy D. , Armiger Yoek Lin See‐Tow 
Published: March 2009

AbstractThe synthesis of three difuryl analogs of the oxophlorins is described. In common with the tetrapyrrolic oxophlorins, these compounds favor the keto tautomers and little, if any, of the enol tautomers are present in neutral solutions. Unlike the tetrapyrrolic systems, the difuryl oxophlorins give well resolved nmr spectra. Attempts to extend these studies to the synthesis of dithienyl oxophlorin analogs were unsuccessful.
Derivatives of 3,4‐dihydro‐2H‐benzo[b][1,4]dioxepin. Preparation of 7,8‐dihydro‐6H‐[1,4]dioxepino[2,3‐f]‐2,1,3‐benzoxadiazole 1‐oxide
Authors: Hadjimihalakis Phaedon M. 
Published: March 2009

AbstractA novel annelated benzofuroxan 4 and a benzofurazan 4a have been prepared in good yields. Nitration of 5 afforded both trinitro derivatives 6 and 7. Low temperature nmr spectroscopy was applied on compound 4 and the value ΔG* is reported.
Ring transformations by ring‐chain‐transfer. V. Synthesis of amino‐, hydroxy‐ and mercaptoalkylpyrazoles by reaction of 3‐functionalized acrylonitriles with hydrazine hydrate
Authors: Paätzel Michael , Liebscher Jürgen 
Published: March 2009

Abstract3‐Alkylamino, 3‐alkoxy or 3‐alkylthioacrylonitriles whose leaving group is incorporated in a saturated heterocyclic ring are 1,3‐bifunctional electrophiles. They react with hydrazine hydrate at the cyano group by addition as well as at position 3 by opening the saturated ring. By this ring transformation new 5‐aminopyrazoles are formed which are additionally substituted by an ω‐functionalized alkyl chain in position 3.
Transformations on 2,3,4,5‐tetrahydrobenzo[b][1,4]‐dioxocin leading to substituted ortho‐nitroaryl azides, benzofuroxans, benzofurazans and related compounds
Authors: Takakis Ioannis M. , Hadjimihalakis Phaedon M. 
Published: March 2009

AbstractNitration of the acetamido‐nitrobenzodioxocins 10, prepared from the corresponding amino derivatives 9, led to the acetamido‐dinitrobenzodioxocins 11, hydrolysis of which furnished the corresponding amines 13. Preparation of the dinitroazides 18 and acetamido‐nitroazides 21 as precursors to substituted dioxocino‐annelated benzofuroxans is described. Thermolysis of the dinitro‐azido derivatives 18a,c,e and/or direct nitration of the unsubstituted benzofuroxans 1a, 2a afforded the isomeric nitrobenzofuroxans 1b, 2b,c. Thermolysis of the acetamido‐nitroazides 21 gave the acetamidobenzofuroxans 1d, 2d,e. All benzofuroxans were deoxygenated to the corresponding benzofurazans 3b,d, 4b‐e. Some aspects of electrophilic and nucleophilic aromatic substitution are discussed.
Synthesis of benzo‐13‐crown‐4 derivatives
Authors: Czech Bronislaw P. , Zazulak Wolodymyr , Kumar Anand , Dalley N. Kent , Weiming Jiang , Bartsch Richard A. 
Published: March 2009

AbstractA series of nine, new benzo‐13‐crown‐4 compounds which bear one or two substituents on the three‐carbon bridge has been prepared in good yields by cesium fluoride‐assisted cyclization reactions of catechol with ditosylates of the appropriate glycols. The solid state structure of 9,9‐dibenzyl‐2,3‐benzo‐13‐crown‐4 is determined and compared with the reported structure for the unsubstituted crown ether.
Nitrogen bridgehead compounds. Part 80 unusual reaction of ethyl 9‐bromo‐4‐oxo‐6,7,8,9‐tetr ahydro‐4h‐pyrido[1,2‐a]pyrimidine‐3‐carboxylates and N‐Methylaniline
Authors: Hermecz István , Breining Tibor , Simon Kálmán , Erös‐Takácsy Tünde , Podányi Benjamin , Sessi John 
Published: March 2009

AbstractThe acid‐catalysed intramolecular nucleophilic addition of the phenyl ring to the C(9a) = N(1) double bond of ethyl 9‐(N‐methyl‐N‐phenyl)‐4‐oxotetrahydro‐4H‐pyrido[1,2‐a]pyrimidine‐3‐carboxylates, formed in the reactions of ethyl 9‐bromo‐4‐oxo‐6,7,8,9‐tetrahydro‐4H‐pyrido[1,2‐a]pyrimidine‐3‐carboxylates and N‐methylaniline, gave the first examples of a new tetracyclic pyrimido[1′,2′:1,2]pyrido[3,2‐b]indole ring system (7). X‐ray diffraction analysis of 7a revealed that the annelation of the pyrimidine and piperidine rings is transoid, while that of the piperidine and pyrroline rings is cis, the piperidine ring adopts an unusual 6T8 twisted boat conformation, while the pyrroline ring has a 9T8a conformation.
Reaction of 2,3‐dichloro‐1,4‐naphthoquinone with dithiooxamide. Synthesis of dibenzo[b,i]thianthrene‐5,7,12,14‐tetrone
Authors: Matsuoka Masaru , Iwamoto Akihiro , Kitao Teijiro 
Published: March 2009

AbstractThe reaction of 2,3‐dihalogeno‐1,4‐naphthoquinone with dithiooxamide gave dibenzo[b,i]thianthrene‐5,7,12,14‐tetrone in high yield but not 2,2′‐bis(naphtho[2,3‐d]thiazole‐4,9‐dione) which was previously reported. A similar reaction of 3,4‐dichloro‐N‐phenylmaleimide with dithiooxamide also gave the corresponding sulfur heterocycles but not the reported bisthiazole.
A facile and practical preparation of 5,7‐dihydroxy‐3‐(4‐nitrophenyl)‐4H‐1‐benzopyran‐4‐one
Authors: Liu D. F. , Cheng C. C. 
Published: March 2009

AbstractIn spite of the fact that several preparative methods for the synthesis of hydroxylated isoflavones were reported during the past fifty years, none is suitable for the preparation of isoflavones containing 5,7‐dihydroxyl functions. This paper reports a simple, large scale preparation of 5,7‐dihydroxy‐3‐(4‐nitrophenyl)‐4H‐1‐benzopyran‐4‐one (2a) by the condensation of the readily available 4‐nitrobenzyl 2,4,6‐trihydroxyphenyl ketone (1a) and acetic‐formic anhydride in high yields. Similar isoflavones, such as 7‐hydroxy‐3‐(4‐nitrophenyl)‐4H‐1‐benzopyran‐4‐one (2b) can also be obtained in good yields in analogous manner.
Synthesis of 5‐(aroylamino)‐2‐methyl‐2H,‐1,2,4‐thiadiazol‐3‐ones by oxidative cyclization of 1‐aroyl‐5‐methyl‐2‐thiobiurets
Authors: Cho Nam Sook , Shon Hyun Il , Párkányi Cyril 
Published: March 2009

Abstract5‐Aroylamino‐2‐methyl‐2H‐1,2,4‐thiadiazol‐3‐ones 3 have been synthesized by oxidative cyclization of 1‐aroyl‐5‐methyl‐2‐thiobiurets 2 with hydrogen peroxide in an alkaline solution. The needed 1‐aroyl‐5‐methyl‐2‐thiobiurets 2 have been obtained through the addition of methylurea to the corresponding aroyl isothiocyanates.
Synthesis and properties of a bilirubin analog with propionic acid groups replaced by carboxyl
Authors: Byun Young‐Seok , Lightner David A. 
Published: March 2009

AbstractThe unnatural bile pigment analog of bilirubin‐IXα, 2,3,7,13,17,18‐hexamethyl‐(10H,21H,23H,24H)‐bilin‐1,19‐dione‐8,12‐dicarboxylic acid (1), was synthesized as its diethyl ester by coupling 4,4′‐dimethyl‐3,3′‐dicarboethoxydipyrrylmethane‐5,5′‐dialdehyde with 3,4‐dimethylpyrrolin‐2‐one.
Synthesis of 2,4‐diamino‐5,10‐dideaza nonclassical antifolates
Authors: Gangjee Aleem , Devraj Rajesh , Lin Fu‐Tyan 
Published: March 2009

AbstractCondensation of 2,4,6‐triaminopyrimidine (8) with bromomalonaldehyde (9) afforded, after pivaloylation, 2,4‐dipivaloyl‐6‐bromopyrido[2,3‐d]pyrimidine (11). This 6‐bromo derivative served as a key intermediate for the synthesis of 2,4‐diamino‐6‐[2‐(3′,4′‐dimethoxyphenyl)ethenyl]pyrido[2,3‐d]pyrimidine (5) via a palladium catalyzed carbon‐carbon coupling with 3,4‐dimethoxystyrene (12). Compound 5, its 9,10‐dihydro analogue 6 and the 5,6,7,8,9,10‐hexahydro analogue 7 were of interest as potential inhibitors of dihydrofolate reductase. Compounds 6 and 7 were synthesized from 5 by catalytic hydrogenation over 5% Pd‐C.
Thermolysis of hexasubstituted‐4,5‐dihydro‐3H‐pyrazoles: Synthesis of 1‐alkoxy‐ and 1‐acetoxy‐1,2,2,3,3‐pentasubstituted‐cyclopropanes
Authors: Kennedy G. Davon , Baumstark Alfons L. , Dotrong M. , Thomas Treye , Narayanan N. 
Published: March 2009

AbstractA series of 5‐alkoxy‐ and 5‐acetoxy‐4,4‐dimethyl‐3,3,5‐trisubstituted‐4,5‐dihydro‐3H‐pyrazoles 2a‐f (hexasubstituted pyrazolines) was synthesized by oxidation of the corresponding 3,4‐dihydro‐2H‐pyrazoles with lead tetraacetate in the appropriate solvents. The 5‐acetoxy compounds were produced when the oxidations were carried out in methylene chloride. Oxidation with lead tetraacetate in dry alcoholic solvents resulted in the formation of the 5‐alkoxy derivatives as the major products. Thermolysis of the hexasubstituted‐4,5‐dihydro‐3H‐pyrazoles 2a‐f in cyclohexane or as the melt at high temperature yielded the 1‐alkoxy‐ and 1‐acetoxy‐1,2,2,3,3‐pentasubstituted cyclopropanes 3a‐f in good yields. Trace amounts of alkene products were formed in several reactions. No products attributable to cycloreversion pathways were detected. The product distributions were consistent with extrusion of nitrogen gas from 2a‐f to yield the singlet 1,3‐diradical, closure of which resulted in cyclopropane formation with partial retention of stereochemistry.
4,5‐Dimethylimidazole: A correction and alternative synthesis
Authors: D'Sa Albinus , Cohen Louis A. 
Published: March 2009

AbstractFractional vacuum distillation of the product obtained from thermal condensation of acetoin with formamide is a formic acid complex of 4,5‐dimethylimidazole, and not the expected free base. The 1H and 13C nmr spectra suggest that the product may be closer to a 1:1 hydrogen‐bonded adduct than to a true salt. Commercial 4‐hydroxymethyl‐5‐methylimidazole is converted quantitatively to the 4‐chloromethyl derivative with thionyl chloride; hydrogenolysis of the latter compound provides 4,5‐dimethylimidazole in an overall 80–90% yield, doubling the yield obtained by the classical method.
Acridine derivatives. IV. Synthesis, molecular structure, and antitumor activity of the novel 9‐anilino‐2,3‐methylenedioxyacridines
Authors: Kimura Michio , Kato Akira , Okabayashi Ichizo 
Published: March 2009

AbstractIn the biological and physical investigation of a new class of deoxyribonucleic acid (DNA)‐intercalating antitumor agents, novel 9‐anilino‐2,3‐methylenedioxyacridines (twelve compounds) have been synthesized and evaluated for the activity against L1210 leukemia in vivo. A few of them possessed the same potency of the antitumor activity as 4′‐(9‐acridinylamino)methanesulfonyl‐m‐anisidine (amsacrine, m‐AMSA), which is an important antitumor agent in clinical use. The molecular structure of a typical one, 9a in this series have been determined by the X‐ray diffraction method using a single crystal. The results of this X‐ray investigation have shown that the new class of acridine derivatives have the methylenedioxy group fused at the 2‐ and 3‐positions of the acridine ring.
Cyclocondensation of 3‐amino‐2‐iminonaphtho[1,2‐d]‐thiazole with α‐ketocarboxylic acid derivatives: Synthesis of 2‐substituted 3‐Oxo‐3H‐naphtho[1′,2′:4,5]thiazolo‐[3,2‐b][1,2,4]triazines as potential anti‐HIV agents
Authors: Liu Kang‐Chien , Shih Bi‐Jane , Lee Chuen‐Hsiang 
Published: March 2009

AbstractThe cyclocondensation of 3‐amino‐2‐iminonaphtho[1,2‐d]thiazole (1) with a series of α‐keto mono‐ and dicarboxylic acid derivatives 5a‐i under different conditions was investigated. When the experiments were performed by refluxing in glacial acetic acid, the corresponding cyclized products, 2‐substituted 3‐oxo‐3H‐naphtho[1′,2′:4,5]thiazolo[3,2‐b][1,2,4]triazines 4 were obtained in fair to good yields. On the other hand, when the reaction was conducted in boiling ethanol, it gave only the open chain condensates 6, or in rare cases, together with minor amount of 4. Since the intermediates 6 exist as mixture of both E‐ and Z‐isomers, cyclization through heating was found insufficient. In any event representative compounds 4b,g,i have been evaluated for anti‐HIV activity, but none of them were active.
Comparative kinetic studies on the synthesis of quinoxalinone derivatives and pyrido[2,3‐b]pyrazinone derivatives by the hinsberg reaction
Authors: Bekerman Diana G. , Abasolo Maria Inés , Fernández Beatriz M. 
Published: March 2009

AbstractKinetic studies on the anelation of quinoxalinone derivatives 3a‐c and pyrido[2,3‐b]pyrazinone derivatives 5a‐c and 6a‐c synthesized by the Hinsberg reaction is reported. o‐Phenylenediamine or 2,3‐diaminopyridine were treated with bifunctional carbonyl compounds such as glyoxylic, pyruvic and benzoylformic acids under different experimental conditions. When pyridopyrazine derivatives were synthesized both position isomers were achieved applying regioselective reactions. Mixture were avoided by looking for special experimental conditions that led unambiguously to only one of the components of the classic “Hinsberg mixture”. Quinoxalinone derivatives 3a‐c were obtained at room temperature in good yields (>90%) using anhydrous methanol or ethanol as solvents. On the other hand, only pyrido[2,3‐b]pyrazin‐3(4H)‐one (5a) was regioselectively attained in aqueous buffer of pH 7 while 3‐methylpyridopyrazinone derivatives were regioselectively separated using anhydrous methanol for one isomer, 5b, and anhydrous chloroform for the other isomer, 6b, at room temperature. Yields were higher than 80%. Reactions with benzoylformic acid did not give good yields and only 2‐phenylpyrido[2,3‐b]pyrazin‐3(4H)‐one (5c) could be obtained using anhydrous chloroform (yield <30%) as the solvent. Steric hindrance exerted by the phenyl group of the benzoylformic acid is supposed to be responsible of our difficulties to obtain 2‐phenylpyrido[2,3‐b]pyrazin‐3(4H)‐one (5c) in good yields applying this technique. The other isomer, 3‐phenyl[2,3‐b]pyrazin‐2(1H)‐one (6c) was always formed together with the former isomer and could not be isolated from the mixture, when other solvents than chloroform were used as the reaction media.
Synthesis of new dibenzo nitrogen‐oxygen donor macrocycles containing two amide groups
Authors: Lindoy Leonard F. , Mahendran Sumathi , Krakowiak Krzysztof E. , An Haoyun , Bradshaw Jerald S. 
Published: March 2009

AbstractFour new nitrogen‐oxygen, dibenzo macrocyclic ligands containing two amide groups have been prepared by combining a dibenzo‐containing diamidodialdehyde with an appropriate diamine followed by reduction of the intermediate bis Schiff‐base. The starting dibenzo‐containing diamidodialdehyde was prepared by treating 2 equivalents of salicylaldehyde with a bis(α‐chloroamide).
Synthesis of isomeric series of aryltetrahydrobenz‐isoxazoles and arylcyclopentisoxazoles
Authors: Fos Empar , Borràs Liset , Gasull Maria , Mauleón David , Carganico Germano 
Published: March 2009

AbstractFour series of potential PAF‐antagonists in which the isoxazole nucleus is condensed with a polyhydrogenated five‐ or six‐carbon ring were prepared. The synthesis of the compounds 3‐aryl‐4,5,6,7‐tetrahydrobenz[c]isoxazoles 1, 3‐arylcyclopent[c]isoxazoles 2, 3‐aryl‐4,5,6,7‐tetrahydrobenz[d]isoxazoles 3, and 3‐arylcyclopent[d]isoxazoles 4, required an extensive optimization and comparison of the methods available in the literature.
One‐pot synthesis of novel spiro‐annelated pyrrole‐containing heterocyclic systems from suitable synthons
Authors: Artico M. , Massa S. , Mai A. , Silvestri R. , Stefancich G. 
Published: March 2009

AbstractNew tetracyclic systems containing a pyrrolobenzodiazepine 5 or a pyrrolobenzotriazepine 6 moiety bounded by a spiro linkage to the piperidine nucleus are described. They have been synthesized by a simple reaction involving the interaction between proper aromatic amines and 4‐oxopiperidines substituted or not at the 1‐position in the presence of maleic acid as a catalyst. The synthesis of spiropyrrolo[1,2‐a]quinoxaline‐2,4′‐piperidine 7 and its 1′‐acyl derivatives by the same procedure is also reported.
Short synthesis of tryptophane and β‐carboline derivatives by reaction of indoles with N‐(diphenylmethylene)‐α,β‐didehydroamino acid esters
Authors: Spadoni Gilberto , Balsamini Cesarino , Bedini Annalida , Duranti Ermanno , Tontini Andrea 
Published: March 2009

AbstractThe ethylaluminum dichloride catalyzed Michael‐type addition of indoles 1a‐h to the N‐(diphenylmethylene)‐α,β‐didehydroamino acid esters 2a‐c allows a new synthesis of β‐methyltryptophanes 41,m and a new route for 1,1‐diphenyl‐3‐carbalkoxy‐1,2,3,4‐tetrahydro‐β‐carbolines 5a‐m.
2‐Aryl‐substituted, benzo‐anellated 5‐membered heterocyclic compounds as potentially active substances for the cardiovascular system: 1,3‐Benzothiazolyl‐ and 1,3‐benzoxazolylbenzylphosphonates
Authors: Rose Ulrich 
Published: March 2009

AbstractIn the course of investigations on structure‐activity relationships of calcium antagonists analogous to fostedil, a series of 2‐aryl‐ and 2‐arylvinyl‐substituted 1,3‐henzothiazoles and 1,3‐benzoxazoles bearing a phosphonate group on the phenyl ring has been synthesized by cyclization, bromination, and subsequent Michaelis‐Arbuzow reaction. Pharmacological investigations on isolated organs from guinea pigs revealed both negative inotropic effects and a relaxing action on smooth musculature; these activities were particularly pronounced in the 1,3‐benzothiazole compound group.
Metalation of diazines. VI. Metalation of pivaloylaminopyrazine and N‐t‐butylpyrazinamide. Unusual regioselectivity in the metalation reaction
Authors: Turck A. , Plé N. , Trohay D. , Ndzi B. , Quéguiner G. 
Published: March 2009

AbstractMetalation of pivalamidopyrazine and N‐t‐butylpyrazinamide were studied. For pivalamido pyrazine the yields were poor and some addition products were isolated. The metalation of t‐butylpyrazinamide was successful and a curious regioselectivity was highlighted.
A new synthesis of N‐substituted‐2‐alkyl(or aryl)quinazolin‐4‐amines by amide base‐mediated cyclization of carbox‐imidamides derived from 2‐(trifluoromethyl)benzenamine
Authors: Patterson Steven E. , Janda Lubomir , Strekowski Lucjan 
Published: March 2009

AbstractA one‐pot preparation of carboximidamides (amidines) 11–14 involves treatment of amides 2–5 with phosphorus pentachloride followed by the treatment of the resultant crude imidoyl chlorides 7–10 with ammonia. Amidines 11–14 are cyclized to quinazolines 20–26 in lithium alkylamide‐or dialkylamide‐mediated reactions.
Thermolysis of 3‐methyl‐3‐(o‐aryl)‐1,2‐dioxetanes: Activation parameters and chemiexcitation yields
Authors: Baumstark Alfons L. , Parker Alesia N. 
Published: March 2009

Abstract3‐Methyl‐3‐(o‐tolyl)‐1,2‐dioxetane 1 and 3‐methyl‐4‐(o‐bromophenyl)‐1,2‐dioxetane 2 were synthesized in low yield by the β‐bromo hydroperoxide method. The activation parameters were determined by the chemilumin‐escence method (for 1 ΔG‡ = 24.7 ± 0.3 kcal/mol, ΔH‡ = 25.4, ΔS‡ = + 1.9 e.u., k60 = 3.4 × 10−4s−1; for 2 ΔG‡ = 24.7 ± 0.4 kcal/mol, ΔH‡ = 24.7, ΔS‡ = 0.0 e.u., k60 = 4.1 × 10−4s−1). Thermolysis of 1–2 directly produced high yields of excited triplets as expected for this type of dioxetane [triplet chemiexcitation yields (ϕ7) for 1 0.03; for 2 0.02; the ϕT/ϕS ratios were estimated to be approximately 200 for both compounds]. The effect of ortho‐aryl substituents was inconsistent with electronic effects. The ortho substitution in 1–2 resulted in a marked increase in stability of the dioxetanes. The results are discussed in relation to a diradical‐like mechanism.
Properties and cage lactone synthesis of diels‐alder adducts from 2‐pyrones
Authors: Shimo Tetsuro , Nagahama Hideki , Yorozu Kiyotaka , Somekawa Kenichi 
Published: March 2009

AbstractNew cage lactones were synthesized by the photocyclization of the tricyclodienolactones 1a, 1b, 2 which were available from the Diels‐Alder reactions of 2‐pyrones with p‐benzoquinones or norbornadiene. Retro‐Diels‐Alder reactions of cross‐adducts between 2‐pyrone‐mono‐adducts and p‐benzoquinone were also described.
Heterocyclic intermediates for the synthesis of disperse and cationic dyes
Authors: Viscardi Guido , Savarino Piero , Barni Ermanno , Carpignano Rosarina , Montoneri Enzo , Quagliotto Pierluigi 
Published: March 2009

AbstractNitro derivatives and amines containing X‐azolo[4,5‐c]pyridine moieties were prepared choosing more favourable synthetic pathways. Their physical and spectroscopic data were discussed in correlation with those of previously studied systems. The heteroaromatic amines were shown to be suitable precursors for the synthesis of disperse dyes and of their cationic counterparts.
Synthesis of indoles via amidoselenation
Authors: Izumi Taeko , Sugano Miwa , Konno Touru 
Published: March 2009

AbstractThe reaction of 2‐styrylacetanilides (2) with N‐phenylselenosuccinimide affords 1‐N‐acetyl‐2‐phenyl‐3‐phenylselenoindoles (3) and 1‐N‐acetyl‐2‐phenylindoles (4). The reaction of 2‐vinylacetanilides (5) with phenylselenenyl bromide proceeds to form indoles via an intramolecular amidoselenation.