bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemistry of the phenoxathiins and isosterically related heterocycles. XXXVII The synthesis and molecular structure of benzo[2, 3]naphtho[5, 6, 7‐ij][1, 4]dithiepin and its 1‐oxide
Authors: Musmar M. J. , Khan Saeed R. , Zektzer Andrew S. , Martin Gary E. , Lynch Vincent M. , Simonsen Stanley H. , Smith Keith 
Published: March 2009

AbstractBenzo[2, 3]naphtho[5, 6, 7‐ij][1, 4]dithiepin was prepared by the condensation of the disodium salt of 1, 2‐dimercaptobenzene with 1‐chloro‐8‐nitronaphthalene. The structure was established by nmr and mass spectroscopy. A small quantity of benzo[2, 3]naphtha[5, 6, 7,ij][1, 4]dithiepin 1‐oxide was also isolated. The structure was initially established by mass spectrometry. The proton spectrum was totally assigned using a combination of proton zero quantum coherence (ZQCOSY) and proton‐carbon heteronuclear chemical shift correlation (HC‐COSY) techniques, which also allowed the unequivocal assignment of the protonated carbon resonances. An X‐ray crystal structure of the 1‐oxide irrefutably confirmed the structure. The crystal was triclinic and the space group was Pl, and the data refined to a final R = 0.0353. The molecule was shown to be folded about the axis passing through the two sulfur atoms with a dihedral angle of 109.00°.
A new class of non‐classical azapentalenes. Synthesis and c‐13/n‐15 NMR characterization of 2H‐imidazo[1, 5‐d]tetrazoles
Authors: L'Abbé Gerrit , Gelinne Marleen , Toppet Suzanne 
Published: March 2009

AbstractThe title compounds 6 (as well as the oxazoles 5) were obtained by thermolysis of 2‐alkyl‐5‐(methoxycarbon‐yldiazomethyl)tetrazoles 3 in benzonitrile. They were fully characterized by 1H, 13C and 15N nmr spectroscopy.
Michael additions with an enaminoester: Reaction of phenyl 4‐chromone‐3‐sulfonate with methyl 3‐amino‐2‐pentenoate
Authors: Löwe Werner , Kradepohl Anneliese 
Published: March 2009

AbstractThe novel benzoxathiinopyridines 5 and 8 and the hitherto unknown oxathiinobenzopyran 17 were synthesized by ring transformations of phenyl 4‐chromone‐3‐sulfonate (1) with methyl 3‐amino‐2‐pentenoate (2). The structures of 5, 8 and 17 were determined by spectroscopic methods and the reaction pathways for the formation of these compounds are discussed.
Regiospecific synthesis of 2‐methyl‐4‐arylcarbonyl‐2H‐1, 2‐benzothiazin‐3(4H)‐one 1, 1‐dioxides
Authors: Marfat A. , Chambers R. J. 
Published: March 2009

AbstractAcylation of 2‐methyl‐2H‐1, 2‐benzothiazin‐3(4H)‐one 1, 1‐dioxide 3 with aryl anhydrides in the presence of dimethylaminopyridine occurs regiospecifically to afford 2‐methyl‐4‐arylcarbonyl‐2H1, 2‐benzothiazin‐3(4H)‐one 1, 1‐dioxides 2a‐f.
Nucleophilic addition of 2‐, 3‐, or 4‐[2‐(methylamino)ethyl]pyridine to the aziridine, 7‐methyl‐7‐azabicyclo[4.1.0]heptane
Authors: Rees David C. 
Published: March 2009

AbstractThe synthesis oftrans‐(±)‐N‐methyl‐N‐[2‐[methyl[2‐(3‐pyridyl)ethyl]amino]cyclohexyl]‐4‐benzofuranacetamide dihydrochloride,1which is a 3‐[2‐(methylamino)ethyl]pyridyl derivative of the kappa opioid analgesictrans‐(±)‐N‐methyl‐N‐[2‐(1‐pyrrolidinyl)cyclohexyl]benzofuran‐4‐acetamide monohydrochloride,2is described. The key intermediate istrans‐(±)‐N,N'‐dimethyl‐N‐[2‐(3‐pyridyl)ethyl]‐1,2‐cyclohexanediamine,9which is formed by nucleophilic addition of 3‐[2‐(methylamino)ethyl]pyridine6to the aziridine, 7‐methyl‐7‐azabicyclo[4.1.0]heptane,4. During attempts to prepare the 2‐ or 4‐isomeric pyridyl derivatives of1it was discovered that both 2‐ or 4‐[2‐(methylamino)ethyl]pyridine,5or7are converted toN‐methyl‐N,N‐di‐[2‐(2‐pyridyl)ethylamine]11andN‐methyl‐N,N‐di[2‐(4‐pyridyl)ethylamine]13respectively by refluxing in toluene in the presence of ammonium chloride. The 3‐isomer,6is unchanged after treatment under identical conditions. Careful control of the reaction conditions enabled the aziridine4to be ring opened with the pyridyl amines5or7to give the 1,2‐diaminestrans‐(±)‐N,N′‐dimethyl‐N‐[2‐(2‐pyridyl)ethyl]‐1,2‐cyclohexanediamine,8ortrans‐(±)‐N,N′‐dimethyl‐N‐[2‐(4‐pyridyl)ethyl]‐1,2‐cyclohexane diamine10respectively.
Synthesis and 13C NMR of (trifluoromethyl)hydroxypyrazoles
Authors: Lee Len F. , Schleppnik Francis M. , Schneider Ronald W. , Campbell Dwane H. 
Published: March 2009

AbstractReaction of ethyl 4,4,4‐trifluoroacetoacetate with methylhydrazine produced not only the previously reported 5‐hydroxy‐3‐(trifluoromethyl)pyrazole 1 but also its unknown isomer the 3‐hydroxy‐5‐(trifluoromethyl)pyrazole 4. The structure assignments are established based on 13C nmr spectra. Compound 1 was converted to 5‐chloro‐3‐(trifluoromethyl)pyrazolecarboxylic acid 3 in two steps.
Reaction of Cα,O‐dilithiooximes with functionalized carbonyl compounds. Part 2. Reaction with α‐chloroketones and α,β‐unsaturated aldehydes and ketones
Authors: Jarrar Adil A. , Hussein Ahmad Q. , Madi Ahmad S. 
Published: March 2009

AbstractThe reaction of Cα,O‐Dilithiooximes 2 and α‐chloroketones afforded 5‐(hydroxymethyl)‐Δ2‐soxazolines 4. α,β‐Unsaturated aldehydes and ketones reacted with 2 to give the corresponding acyclic 1,2‐addition products 5. The latter were cyclized with phosphorus pentoxide to 5‐vinyl‐Δ2‐isoxazolines 6.
Synthesis of 4,4‐dimethyl‐3,4‐dihydro‐3,3,5‐trisubstituted‐2H‐pyrazoles and N‐benzoyl derivatives: Method for “Hydrolysis” of unreactive amides and carbamates
Authors: Baumstark Alfons L. , Choudhary Anil , Vasquez Pedro C. , Dotrong My 
Published: March 2009

AbstractAddition of organolithium reagents to 4,4‐dimethyl‐3,5‐disubstituted‐4H‐pyrazoles produced a series of 4,4‐dimethyl‐3,4‐dihydro‐3,3,5‐trisubstituted‐2H‐pyrazoles, 2–6, in good yield. The reaction was stereoselective: addition of organolithium compounds occurred only to carbon‐3 of 4,4‐dimethyl‐3‐alkyl‐5‐aryl‐4H‐pyrazoles. The 3,4‐dihydro‐2H‐pyrazoles were found to be of high sensitivity to oxygen. For long term storage and ease of handling, N‐benzoyl derivatives were synthesized. Removal of the protecting group could not be accomplished by use of many standard sets of conditions. Deprotection was accomplished in high yield by reaction of the N‐benzoyl‐4,4‐dimethyl‐3,4‐dihydro‐3,3,5‐trisubstituted‐2H‐pyrazoles with anhydrous potassium t‐butoxide in toluene [heated under reflux (ultra‐pure argon)] in the presence of a phase transfer catalyst (18‐Crown‐6). Cleavage of a N‐carbamate derivative was also achieved by this phase transfer approach. This methodology should be applicable to the hydrolysis of unreactive amides and carbamates in general.
Effects of substituents on the chlorination of methyl 3‐hydroxythiophene‐2‐carboxylate and on the reaction of the resulting chlorinated products with active hydrogen containing compounds
Authors: Corral Carlos , Lissavetzky Jaime , Manzanares Ignacio 
Published: March 2009

AbstractThe title tandem reactions that produce 5‐substituted compounds of methyl 3‐hydroxythiophene‐2‐carboxylate can also be applied with a minor modification to the 4‐alkyl and 4‐aryl derivatives thereof. On the other hand, 5‐alkyl and 5‐aryl derivatives that undergo a similar smooth chlorination behave in the second reaction in a different manner.
Synthesis and x‐ray crystal structures of isonipecotinamide derivatives as reverse amide analogues of fentanyl
Authors: Borne Ronald F. , Gatchell Catherine L. , Klein Cheryl L. , Harris John , Ellis Portia 
Published: March 2009

AbstractSeveral isonipecotinamide derivatives which represent reverse amide derivatives of the potent analgetic agent fentanyl were prepared and evaluated for analgetic activity. The synthetic approaches utilized and stereochemical assignments are discussed. The most potent compound,3, displayed much weaker analgetic activity than fentanyl itself.
A new approach for the synthesis of pteridines: The synthesis of 3‐substituted‐2‐thioxo‐1,2‐dihydro‐4(3H)‐pteridinones
Authors: Urleb Uros , Neidlein Richard , Kramer Walter 
Published: March 2009

Abstract3‐Substituted‐2‐thioxo‐1,2‐dihydro‐4(3H)‐pteridinones can be conveniently prepared by the reaction of methyl 3‐isothiocyanato‐2‐pyrazinecarboxylate 2 with N‐nucleophiles. The scope and limitations of the method are presented. The tautomeric form of 2‐thioxo‐1,2‐dihydro‐4(3H)pteridinones was determined on the basis of a 13C‐[1H]‐NOE experiment.
A new heterocyclic structure. The 6H‐[1,3]benzoxathiepino[5,4‐d]pyrimidine 5,5‐dioxide
Authors: Löwe Werner , Troll Achim 
Published: March 2009

AbstractThe novel benzoxathiepinopyrimidines 6a‐d were synthesized by ring transformations of 3‐chloromethylsulfonylchromone (2) with amidines 3a‐d.
New synthetic method for 4‐hydroxyproline
Authors: De Martino Giovanni , De Caprariis Paolo , Abignente Enrico , Rimoli Maria Grazia 
Published: March 2009

AbstractA new synthesis of 4‐hydroxyproline was carried out starting from diethyl p‐nitrobenzoylaminomalonate, which was converted by a three steps pathway into diethyl 4‐hydroxy‐1‐(4‐nitrobenzoyl)pyrrolidine‐2,2‐dicarboxylate, which afforded 4‐hydroxyproline via acid hydrolysis.
Synthesis and reactions of 3‐thioxo[1,2,4]‐triazino[3,2‐b]quinazolin‐10‐ones
Authors: Eid Mohga M. , El‐Zanaty Ali , Ibrahim Yehia A. 
Published: March 2009

AbstractThiation of [1,2,4]triazino[3,2‐b]quinazoline‐3,10‐dione 1 proceeds selectively to give the 3‐thioxo‐analog 3. The latter was converted to the corresponding 3‐methylthio derivative 4 which was reacted with aniline and hydrazine to give the corresponding anilino‐ and hydrazino derivatives 5 and 7. Compound 7 was converted to the hydrazones 8a,b and into the novel heterocyclic ring systems [1,2,4]triazolo[4′,3′:4,5][1,2,4]triazino‐[3,2‐b]quinazolin‐7‐ones 9, 10a,b and tetrazolo[1′,5′:4,5][1,2,4]triazino[3,2‐b]quinazolin‐7‐one 11.
A facile synthesis of novel triazoloquinoxahnones and triazinoquinoxalinones
Authors: Rashed Nagwa , El Massry Abdel Moneim , El Ashry El Sayed H. , Amer Adel , Zimmer Hans 
Published: March 2009

AbstractA series of 1‐aryl‐s‐triazolo[4,3‐a]quinoxalin‐4‐ones, 3, were synthesized via the pyrolysis of the corresponding hydrazones, 6. Thus, the cyclodehydrogenation occurred by refluxing them in an inert solvent (e.g. ethylene glycol) to give the triazoloquinoxalin‐4‐ones in a satisfactory yield. Using DMSO as a solvent for the above transformation afforded as a minor by‐product an S‐ylid. In contrast to earlier findings, annelation of a six‐membered ring was successful and achieved through the pyrolysis of the pyruvate hydrazones derived of the quinoxalin‐4‐ones at −230° to give the as‐triazino[4,3‐a]quinoxalin‐5‐ones, 4. The reaction of 5 with acetylacetone afforded 3‐(3′,5′‐dimethylpyrazol‐1‐yl)‐2(1H)‐quinoxalinone, 10. The structural assignments for the new compounds were based on their elemental analysis and spectroscopic data as well as an independent synthesis.
A Novel synthesis of 6‐hydroxyalkyl‐and 6‐hydroxy‐aralkyl‐6H‐dibenz[c,e][1,2]oxaphosphorin 6‐Oxides
Authors: Yamada Yoichi , Yasuda Heinosuke , Saito Toranosuke 
Published: March 2009

AbstractA new strategy for the synthesis of 6‐hydroxyalkyl‐ and 6‐hydroxyaralkyl‐6H‐dibenz[c,e][1,2]oxaphosphorin 6‐oxides 3 was achieved by the reaction of 2‐(2‐hydroxyphenyl)phenylphosphonic acid (1) with various carbonyl compounds 2. The desired products 3 were obtained in acceptable yields.
Saturated heterocycles, 162 [1]. synthesis and steric structures of 3,4‐disubstituted 1,6,7,11b‐tetrahydropyrimido[6,1‐a]isoquinolin‐2‐ones
Authors: Fulöp Ferenc , Semega Eva , Bernáth Gábor , Sohár Pál 
Published: March 2009

AbstractThe reaction of 1‐(hydrazidomethyl)‐6,7‐dimethoxy‐1,2,3,4‐tetrahydroisoquinoline 3 with aromatic aldehydes yield hydrazones 4a,b or pyrimido[6,1‐a]isoquinolines 5a‐c depending upon the proportions of the reagents. With ketones, 3 gives only hydrazones 4a‐d and 7, which can be transformed to pyrimidoisoquinolines 10a‐e and 11 with aldehydes. The ring closures are stereospecific; the relative configurations were determined by DNOE measurements.
4,4′‐Coupled bis(isoquinolines)
Authors: Guilani Bardia , Rasco Melvin L. , Hermann Christine F. K. , Gibson Harry W. 
Published: March 2009

AbstractReaction of the eneamine 1 formed in situ from isoquinoline and sodium triethylborohydride with aromatic dialdehydes 3 produces 4,4′‐coupled bis(isoquinolines) 4 in good yields. These compounds are readily oxidized with manganese dioxide to the corresponding diketones 5.
Synthesis and stereochemistry of rac.‐trans‐tetrahydro‐6‐hydroxy‐7‐(4‐methoxyphenyl)‐1,4‐thiazepin‐5(2H)‐one
Authors: Mohacsi Erno , O'Brien Jay P. , Todaro Louis J. 
Published: March 2009

AbstractThe base catalyzed reaction of 2‐aminoethanethiol (3) with trans‐3‐(p‐methoxyphenyl)glycidate (4) gave a mixture of isomeric lactams 5 and 6, and in addition, a by‐product 7. The structures of these isomers were proven by X‐ray crystallography. The data revealed that both isomers adopt the chair conformation in the solid state and the size of the heterocyclic ring in compound 5 is a six‐ and in compound 6 is a seven‐membered ring.
1,3‐dipolar cycloaddition as applied to the synthesis of 5‐cyano‐1‐(1,1‐dimethylethyl)‐N‐methyl‐1H‐pyrazole‐4‐carboxamide
Authors: Tao E. V. P. , Rizzo John R. , Aikins James 
Published: March 2009

AbstractThe title compound was synthesized via 1,3‐dipolar cycloaddition of diazoacetonitrile and diethyl fumarate.
Synthesis and regiospecificity in methylation of pyrido[1,2‐a]pyrazinium‐1‐ and 3‐olates and pyrido[1,2‐b]pyridazinium‐2‐ and 4‐olates
Authors: Bátori Sándor , Messmer András 
Published: March 2009

AbstractNew methods have been developed for the synthesis of pyrido[1,2‐a]pyrazinium‐1‐ and 3‐olates 5a‐f, 9 and 1‐thiolate 24 as well as of pyrido[1,2‐b]pyridazinium‐4‐ and 2‐olates 14, 20. The methylation of these new compounds was studied by soft and hard methylating agents. Depending on the nature of the reagent used, the pyrido[1,2‐a]pyrazinium‐1‐olates 5a‐f gave NMe 22a‐f and/or OMe 23a‐f products, whereas the 3‐olate 9 and both the 4‐ and 2‐pyridazinium‐olates 14, 20 afforded solely OMe compounds 10, 15, 21. A selectivity rule for methylation is proposed.
On triazoles. XXII. Synthesis of Dialkyl (3‐Q‐1,2,4‐triazol‐5‐yl)iminodithiocarbonates
Authors: Reiter József , Pongó László , Pallagi István 
Published: March 2009

AbstractIsomeric dialkyl and diaralkyl[1‐, 2‐ and 4‐(alkyl, aralkyl and aryl)‐3‐Q‐1,2,4‐triazole‐5‐yl]iminodithiocarbonates 4a‐c (R ≠ H) were synthesised and their spectral data compared. The uv, cmr and ms rules elaborated helped to prove the tautomeric structure of the non‐substituted derivatives 4 (R  H). In case of dimethyl (3‐methylthio‐1,2,4‐triazole‐5‐yl)iminodithiocarbonate this is the first time ever crystalline triazole desmotropes 4a/17 and 4b/17 could be isolated. The sodium salts of 4 (R  H) could be further alkylated and aralkylated to yield the corresponding 4 (R  alkyl and aralkyl) type derivatives. Providing the above reaction in the presence of carbon disulfide the dithiocarbomethoxy derivative 7 was obtained.
A conformational analysis of the six isomers of oxybispyridine
Authors: Dunne Simon J. , Summers Lindsay A. , Von Nagy‐Felsobuki Ellak I. 
Published: March 2009

AbstractConformational energy contour maps of the six isomers of oxybispyridine have been constructed using the ab initio STO‐3G molecular orbital method. The calculations (employing a partial rigid rotor) for all six isomers indicate that the minimum energy conformers are not planar and that energy barriers between 70–1000 kJ mol−1 restrict interconversion to planar structures, thereby preventing conjugation between the p‐electrons of the oxygen atom with the π system of the pyridine rings. It is postulated that of the three mechanisms used to explain conformer interconversion about the CO bond, the disrotatory one‐ring flip mechanism is the most appropriate, since the “Morino's” structures are all within 2.5 kJ mol−1 of the minimum. Furthermore, room temperature accessibility of the “Morino's” structures suggests that the Smiles rearrangement would be possible for suitably substituted derivatives of these isomers.
The reaction of ethyl 4H‐pyran‐4‐one‐2‐carboxylate with 1,2‐diaminobenzene
Authors: Markees Diether G. 
Published: March 2009

AbstractEthyl 4H‐pyran‐4‐one‐2‐carboxylate was allowed to react with 1,2‐diaminobenzene and related diamines. The resulting products were found to be 8H‐5,6‐dihydro‐6,8‐dioxopyrido[1,2‐a]quinoxaline and derivatives. The synthesis 3H‐5,6‐dihydrobenzo[g]pyrido[1,2‐a]quinoxaline‐3,5‐dione (2c) constitutes the synthesis of a derivative of previously unknown benzo[g]pyrido[1,2‐a]quinoxaline ring system.
A new synthesis of 7‐substituted 2,3‐bis(alkylthio)naphth[1,8‐bc]‐azepines using the tris(alkylthio)cyclopropenyl cation
Authors: Kojima Hideo , Ozaki Kazuyoshi , Matsumura Noboru , Inoue Hiroo 
Published: March 2009

Abstract7‐Substituted 2,3‐bis(isopropylthio)naphth[1,8‐bc]azepines 3a‐c were synthesized in good yields by the reactions of 5‐substituted 1‐naphthylamines 2a‐c with tris(isopropylthio)cyclopropenylium perchlorate (1) in acetonitrile under reflux. This reaction proceeds through the facile ring opening of 1, followed by the intermediary formation of iminium salts 5a‐c and then intramolecular cyclization.
Synthesis and biological evaluation of 5‐substituted‐4‐nitroimidazole ribonucleosides
Authors: Hasan Ahmad , Lambert Carla R. , Srivastava Prem C. 
Published: March 2009

AbstractThe imidazole nucleosides, 4(5)‐bromo‐5(4)‐nitro‐1‐β‐D‐ribofuranosylimidazoles, have been prepared via glycosylation of the trimethylsilylated aglycone, 4(5)‐bromo‐5(4)‐nitroimidazole, with tetra‐O‐acetyl‐β‐D‐ribo‐furanose followed by removal of the acetyl protecting groups. The 5‐bromo‐4‐nitro‐1‐β‐D‐ribofuranosylimidazole nucleoside was acetonated to produce 5‐bromo‐4‐nitro‐1‐(2,3‐O‐isopropylidene‐β‐D‐ribofuranosyl)‐imidazole which was cyclized to provide the corresponding anhydronucleoside 5,5′‐anhydro‐4‐nitro‐5‐oxo‐1‐(2,3‐O‐isopropylidene‐β‐D‐ribofuranosyl)imidazole. Sodium hydrosulfide treatment of 5‐bromo‐4‐nitroimidazole nucleoside provided 5‐mercapto‐4‐nitro‐1‐β‐D‐ribofuranosylimidazole 5‐sodium salt which was alkylated with E‐1,5‐diiodopent‐1‐ene to yield 5‐(E‐1‐iodo‐1‐penten‐5‐yl)thio‐4‐nitro‐1‐β‐D‐ribofuranosylimidazole. The corresponding iodine‐125‐labeled compound was prepared similarly using radiolabeled diiodopentene. The 5‐bromo‐4‐nitroimidazole, 5‐mercapto‐4‐nitroimidazole, and 5‐iodopentenylthio‐4‐nitroimidazole nucleosides were cytotoxic to Molt‐3 cells in vitro at concentrations higher than 10 μg/mL. The radiolabeled 5‐iodopentenylthio‐4‐nitroimidazole nucleoside showed 2‐fold higher uptake in a rapidly growing tumor as compared to uptake in a relatively slower growing tumor in mice.
Saturated heterocycles, Part 172. Synthesis of 2,6‐disubstituted‐5,6,7,8‐tetrahydropyrido[4,3‐d]pyrimidine derivatives
Authors: Lázár János , Bernáth Gábor 
Published: March 2009

AbstractThe title compounds were synthesized via the addition of methyl acrylate to benzylamine or to α‐aminopyridine, which gave the corresponding diesters, e.g. 12, followed by Dieckmann condensation of the latter to yield the keto‐esters 13, which were condensed with amidines and guanidines, 3, 14. Removal of the benzyl group by hydrogenolysis and subsequent alkylation of the nitrogen atom at position 6 in the resulting compound 5, with variation of the substituents on C‐2, gave a number of products with potential biological action; some of them gave analgesic and anti‐inflammatory effects.
A convenient synthesis of 1‐aryl‐3‐methyl‐1,2,4‐triazolin‐5‐ones from the reaction between acetone arylhydrazones and acetyl isocyanate
Authors: Ray Partha S. , Hank Richard F. 
Published: March 2009

AbstractThe reaction of acetone arylhydrazones with acetyl isocyanate gave the corresponding 4‐acetyl‐1‐aryl‐3,3‐dimethyl‐1,2,4‐triazolidin‐5‐ones which eliminated acetone upon acidic hydrolysis to give 1‐aryl‐3‐methyl‐1,2,‐4‐triazolin‐5‐ones. The above transformation can be achieved in one pot by a simple solvent swap.
Synthesis of substituted [1]benzothieno[2,3‐b]pyrazines
Authors: Cannizzo Sergio , Guerrera Francesco , Siracusa Maria Angela , Corsaro Antonino 
Published: March 2009

AbstractThe synthesis of a series of novel 1‐unsubstituted and 1‐alkyl‐1,2,3,4‐tetrahydro[1]benzothieno[2,3‐b]‐pyrazine‐2,3‐diones 4a‐d and their corresponding dialkylaminoalkylamino derivatives 6a‐d starting from 2‐nitro‐3‐bromobenzo[6]thiophene is described. The title ring system has not been reported previously.
Synthesis of 1‐functionalized‐6‐hydroxy‐4‐methyl and 6,11‐dihydroxy‐4‐methylnaphtho[2,3‐g]isoquinoline‐5,12‐quinones
Authors: Croisy‐Delcey Martine , Bisagni Emile , Huel Christiane , Zilberfarb Danielle , Croisy Alain 
Published: March 2009

AbstractUsing 2‐methoxy‐ and 2,5‐dimethoxyacetophenones 8a and 8b as starting materials, 1‐chloro‐4‐methylisoquinoline‐5,8‐quinone (6) and its 6‐bromo derivative 7 were obtained via multistep sequences. Whereas Diels‐Alder condensation of the former compound with homophthalic anhydride (22) led to a mixture of the two possible isomers: 1‐chloro‐11‐hydroxy‐4‐methylnaphtho[2,3‐g]isoquinoline‐5,12‐quinone (23) and 1‐chloro‐6‐hydroxy‐4‐methylnaphtho[2,3‐g]isoquinoline‐5,12‐quinone (24), this last tetracyclic chloroquinone was specifically obtained from 6‐bromo‐1‐chloro‐4‐methylisoquinoline‐5,8‐quinone (7) and homophthalic anhydride. The 6,11‐dihydroxy derivative was then prepared by ammonium nitrate oxidation or photochemically by cycloaddition of benzocyclobutenedione (28) and 1‐chloro‐4‐methylisoquinoline‐5,8‐quinone (6). Chloro compounds were easily substituted by diamines to provide corresponding 1‐amino substituted hydroxy tetracyclic quinones.
Thermal decomposition of 3,3,5‐trisubstituted‐4,4‐dimethyl‐4,5‐dihydro‐5‐hydroperoxy‐3H‐pyrazoles: Route to β,γ‐unsaturated ketones
Authors: Baumstark Alfons L. , Vasquez Pedro C. 
Published: March 2009

AbstractThe thermal decomposition of a series of cyclic α‐azo hydroperoxides (3,3,5‐R1, R2, R3‐4,4‐dimethyl‐4,5‐dihydro‐5‐hydroperoxy‐3H‐pyrazoles; 2a R1 = R2 = R3 = Ph; 2b R1 = R3 = Ph, R2 = Me; 2c R1 = R3 = p‐Anisyl, R2 = Me; 2d R1 = R2 = Me, R3 = Ph; 2e R1 = R3 = Me, R2 = Ph), synthesized by oxidation of the corresponding 3,4‐dihydro‐2H‐pyrazoles, proceeded smoothly with evolution of nitrogen. The relative stability series was found to be 2a > 2c ≈︁ 2b > 2d > 2e. For 2a, the products were 1,4,4‐triphenyl‐2,2‐dimethyl‐1‐propanone and 1,1‐dimethyl‐2,2‐diphenylethylene. For 2b‐e, β,γ‐unsaturated ketones [R1‐C(= CH2)‐CMe2‐C(= O)R3, 5a‐d] were obtained as the major products in ∼60% yield from the thermolyses. The products are consistent with a free‐radical mechanism involving initial homolysis of the O‐O bond followed by loss of nitrogen to yield a free‐radical beta to the carbonyl group. For 2a, β‐scission and hydrogen‐atom abstraction of the hydroperoxy proton by the β‐keto radical (induced decomposition) are the major pathways leading to products. For 2b‐c, abstraction of a γ‐hydrogen atom of the β‐keto radicals by hydroxy radical accounts for the formation of the β,γ‐unsaturated compounds as the major product.
Synthesis of the piperidinone metabolites of piperidine type phenothiazine antipsychotic drugsviaruthenium tetroxide oxidation
Authors: Lin G. , Midha K. K. , Hawes E. M. 
Published: March 2009

AbstractThe lactam metabolites of the piperidine type phenothiazine antipsychotic drugs thioridazine, mesoridazine and sulforidazine were synthesized in six steps from commercially available 2‐(2‐hydroxyethyl)piperidine. The key step involved ruthenium tetroxide oxidation ofN‐protected 2‐(2‐chloroethyl)piperidine. The products were then oxidized to obtain the phenothiazine ring 5‐sulfoxide analogues.