bluuebunny/crossref_metadata_2025_split huggingface dataset:
An unexpected aminolysis in the synthesis of 5‐substituted 3‐(1H‐tetrazol‐5‐yl)pyrazolo[1, 5‐a]quinazolines
Authors: Peet Norton P. 
Published: March 2009

AbstractA synthetic route to 5‐substituted 3‐(1H‐tetrazol‐5‐yl)pyrazolo[1, 5‐a]quinazolines is described. An unexpected displacement of a 4‐morpholinyl group from the 5‐position of this system occurred during tetrazole formation by the ammonia produced byin situgeneration of hydrazoic acid from ammonium chloride and sodium azide.
Cyclization reactions of 3‐hydrazino[1, 2, 4]triazino[5, 6‐b]indole
Authors: Abdel‐Latif F. F. , Shaker R. M. , Mahgoub S. A. , Badr M. Z. A. 
Published: March 2009

AbstractThe reaction of 3‐hydrazino[1, 2, 4]triazino[5, 6‐b]indole I with nitrous acid affords the azide III which could be cyclized with acetic anhydride to 10‐acetyl‐10H‐tetrazolo[5′,1′:3, 4][1, 2, 4]triazino[5, 6‐b]indole IIb. Cyclization reactions of I with acetic anhydride, ethyl chloroformate, carbon disulphide and aromatic aldehydes to the corresponding fused triazolo derivatives V–VIII are reported. On the other hand cyclization reactions of I with malononitrile, ethyl cyanoacetate, ethyl acetoacetate and acetylacetone to the corresponding condensed pyrazolino derivatives IX–XI are also reported. The reaction of I with α‐dicarbonyl compounds to form mono and dihydrazones are reported. The structure of the compounds prepared and their cyclization mechanisms are reported.
Synthesis and reactions of 2‐amino‐7, 8‐dimethoxy‐1h‐3‐benzazepines. Competitive formation of 2‐amino‐1h‐3‐benzazepinesvs. 2‐benzylimidazoles
Authors: Robey R. L. , Copley‐Merriman C. R. , Phelps M. A. 
Published: March 2009

AbstractA short synthesis of 2‐amino‐7, 8‐dimethoxy‐1H‐3‐benzazepine (1a) from 3, 4‐dimethoxyphenylacetonitrile (8a) is reported. The synthesis of several other 2‐amino‐1H‐3‐benzazepines1is also discussed. Conditions which favor the formation of1versusthe formation of the isomeric 2‐benzylimidazoles11are evaluated. Several reactions of1aare also described.
Syntheses of 4,7‐Dimethyl‐6‐phenyl‐5,6,7,8‐tetrahydro‐4H‐1,3,6‐dioxazocin‐2‐ones and its related compounds
Authors: Nishiyama Tomihiro , Yamaguchi Hiromasa , Yamada Fukiko 
Published: March 2009

AbstractFour isomeric 4,7‐dimethyl‐6‐phenyl‐5,6,7,8‐tetrahydro‐4H‐1,3,6‐dioxazocin‐2‐ones and four isomeric 4,7‐dimethyl‐6‐phenyl‐5,6,7,8‐tetrahydro‐4H‐1,3,2,6‐dioxathiazocine 2‐oxides were prepared. On the basis of the nmr chemical shifts due to the γ‐effect, the stereochemical structures are discussed.
A Synthesis of imidazo‐ and pyrimido[1,2‐g][1,6]naphthyridinones
Authors: Friary R. , Schwerdt J. H. , Seidl V. , Villani F. J. 
Published: March 2009

AbstractArylmethylimidazolines and (3‐chlorophenyl)methyl‐1,4,5,6‐tetrahydropyrimidine amidated 2‐chloro‐3‐pyridinecarbonyl chloride, and potassiumt‐butoxide cyclized the products to linearly fused, tricyclic imidazo‐and pyrimido[1,2‐g][1,6]naphthyridinones. Condensation of ethyl 2‐chloro‐3‐pyridinecarboxylate with 2‐(phenylmethyl)imidazoline in the presence of sodium methoxide directly formed the isomeric, angularly fused 8,9‐dihydro‐6‐phenylimidazo[1,2‐a][1,8]naphthyridin‐5(7H‐one.
Synthesis and stereochemistry of novel [1,2,4]oxadiazolo[4,5‐a][1,5]benzodiazepine derivatives
Authors: Chimirri Alba , Grasso Silvana , Ottanà Rosaria , Romeo Giovanni , Zappalà Maria 
Published: March 2009

AbstractAn one‐pot synthetic approach to the novel 3a,4,5,6‐tetrahydro[1,2,4]oxadiazolo[4,5‐a][1,5]benzodiazepine system, by 1,3‐dipolar cycloaddition of benzonitriloxides to 1,5‐benzodiazepine derivatives, is described. The structure and stereochemistry of the obtained adducts have been assigned by means of spectroscopic measurements.
Synthesis of certain pyrazolo[3,4‐d]pyrimidin‐3‐one nucleosides
Authors: Anderson Jack D. , Cottam Howard B. , Larson Steven B. , Dee Nord L. , Revankar Ganapathi R. , Robins Roland K. 
Published: March 2009

AbstractSynthesis of the pyrazolo[3,4‐d]pyrimidin‐3‐one congeners of guanosine, adenosine and inosine is described. Glycosylation of 3‐methoxy‐6‐methylthio‐1H‐pyrazolo[3,4‐d]pyrimidin‐4(5H)‐one (13) with 1‐O‐acetyl‐2,3,5‐tri‐O‐benzoyl‐D‐ribofuranose (16) in the presence of boron trifluoride etherate gave 3‐methoxy‐6‐methylthio‐1‐(2,3,5‐tri‐O‐benzoyl‐β‐D‐ribofuranosyl)pyrazolo[3,4‐d]pyrimidin‐4(5H)‐one (17) which, after successive treatments with 3‐chloroperoxybenzoic acid and methanolic ammonia, afforded 6‐amino‐3‐methoxy‐1‐β‐D‐ribofuranosylpyrazolo[3,4‐d]pyrimidin‐4(5H)one (18). The guanosine analog, 6‐amino‐1‐β‐D‐ribofuranosylpyrazolo[3,4‐d]pyrimidine‐3,4(2H,5H)‐dione (21), was made by sodium iodide‐chlorotrimethylsilane treatment of 6‐amino‐3‐methoxy‐1‐(2,3,5‐tri‐O‐acetyl‐β‐D‐ribofuranosyl)pyrazolo[3,4‐d]pyrimidin‐4(5H)one (19), followed by sugar deprotection. Treatment of the adenine analog, 4‐amino‐1H‐pyrazolo[3,4‐d]pyrimidin‐3(2H)‐one (11), according to the high temperature glycosylation procedure yielded a mixture of N‐1 and N‐2 ribosyl‐attached isomers. Deprotection of the individual isomers afforded 4‐amino‐3‐hydroxy‐1‐βribofuranosylpyrazolo‐[3,4‐d]pyrimidine (26) and 4‐amino‐2‐β‐D‐ribofuranosylpyrazolo[3,4‐d]pyrimidin‐3(7H)‐one (27). The structures of 26 and 27 were established by single crystal X‐ray diffraction analysis. The inosine analog, 1‐β‐D‐ribofuranosylpyrazolo[3,4‐d]pyrimidine‐3,4(2H,5H)‐dione (28), was synthesized enzymatically by direct ribosylation of 1H‐pyrazolo[3,4‐d]pyrimidine‐3,4(2H,5H)‐dione (8) with ribose‐1‐phosphate in the presence of purine nucleoside phosphorylase, and also by deamination of 26 with adenosine deaminase.
Nitration studies of naphtho[2,3‐c][1,2,5]thiadiazole
Authors: Smith Walter T. , Patterson John M. , Kovelesky Albert C. 
Published: March 2009

AbstractNitration of naphtho[2,3‐c][1,2,5]thiadiazole gives the 5‐nitro derivative in 61–66% yield. Chlorination of this product apparently gives an unstable addition product which loses hydrogen chloride on recrystallization to give 4‐chloro‐8‐nitronaphtho[2,3‐c][1,2,5]thiadiazole. Thus, naphtho[2,3‐c][1,2,5]thiadiazole under nitrating conditions behaves as a 2‐substituted naphthalene rather than as an anthracene analog.
A 1H and 13c Nmr study of the structure and tautomerism of 4‐pyrazolylpyrazolinones
Authors: Elguero J. , Martíanez A. , Singh S. P. , Grover M. , Tarar L. S. 
Published: March 2009

AbstractIt has been established that the primary reactions products between dehydroacetic acid and p‐chlorophenylhydrazine or 4‐phenylthiazol‐2‐ylhydrazine are 4‐acetylacetyl‐5‐hydroxypyrazoles. These compounds react with the above hydrazines to yield 4‐(pyrazol‐5′‐yl)‐2‐pyrazolin‐5‐ones which exist in solution as 5‐hydroxypyrazoles.
Synthesis and stereochemistry of tetrahydro‐4‐aryl‐3‐[(dimethylamino)methyl]‐2H‐pyranols as potential analgesics
Authors: Mohacsi Erno , O'Brien Jay P. , Blount John F. , Sepinwall Jerry 
Published: March 2009

AbstractDiastereomericcis‐ andtrans‐tetrahydro‐4‐aryl‐3‐[(dimethylamino)methyl]‐2H‐pyranols derived from 3‐[(dimethylamino)methyl]tetrahydro‐4H‐pyran‐4‐one (5), have been prepared and their configurations were established on the basis of ir data. The biologically more potenttransisomer3was resolved into its optical antipodes and the absolute stereochemistry of one of the enantiomers14, was determined by X‐ray crystallography. Some of the compounds showed analgesic activity comparable to codeine.
The improved convergent syntheses of arecolones and isoarecolone
Authors: Ward John S. , Merritt Leander 
Published: March 2009

AbstractGood yields of arecolone and isoarecolone were obtained by treating theN,O‐dimethylamides of arecaidine and isoarecaidine, respectively, with methylmagnesium chloride. Other substituted arecolones were synthesized by this same strategy.
The electron transfer reactions of cyano substituted pyridines and quinolines with thermally generated diphenyl ketyl
Authors: Mcdevitt Patricia , Vittimberga Bruno M. 
Published: March 2009

AbstractElectron transfer reactions of cyano substituted pyridines and quinolines with thermally generated diphenyl ketyl are reported. When E1/2(‐) for the heterocycle is less negative than ‐2V, electron transfer occurs from the ketyl to the heterocyclic base. In some cases the products obtained from the thermal reaction are the same as those obtained from the photochemical reaction with benzophenone and alcohols. In other cases different products are formed. Two bases, 2‐pyridinecarbonitrile and 2,4‐pyridinedicarbonitrile, undergo regiospecific reactions in which the course of the reaction is determined by the acidity of the medium. A mechanism in which the heterocyclic nitrogen is involved in the substitution process at the 2 position is proposed.
An improved synthesis of 3,6‐diamino‐1,2,4,5‐tetrazine. I
Authors: Coburn Michael D. , Ott Donald G. 
Published: March 2009

AbstractTreatment of 1,3‐diaminoguanidine monohydrochloride (1) with 2,4‐pentanedione (2) in alcohols under carefully controlled conditions gave 3,6‐diamino‐1,2‐dihydro‐1,2,4,5‐tetrazine monohydrochloride (3) in 45‐50% yields along with 3,5‐dimethyl‐1H‐pyrazole (4) and its hydrochloride 5. Oxidation of 3 with sodium perborate produced 3,6‐diamino‐1,2,4,5‐tetrazine (6) in quantitative yield.
Methylation of 2,4‐dihydro‐3H‐1,2,4‐triazol‐3‐ones. A structural determination of anhydro‐5‐aryl‐1,4‐dimethyl‐3‐hydroxy‐1,2,4‐triazolium hydroxides by two dimensional NMR
Authors: Huber Edward W. , Kane John M. 
Published: March 2009

AbstractThe syntheses of 5‐[3‐(n‐butoxy)‐4‐methoxyphenyl]‐4‐methyl‐2,4‐dihydro‐3H‐1,2,4‐triazol‐3‐one (6) and 5‐[3‐(n‐butoxy)‐4‐methoxyphenyl]‐2,4‐dimethyl‐2,4‐dihydro‐3H‐1,2,4‐triazol‐3‐one (7) are reported. The alkylation of6with methyl iodide to yield7also yields anhydro‐5‐[3‐(n‐butoxy)‐4‐methoxyphenyl]‐1,4‐dimethyl‐3‐hydroxy‐1,2,4‐triazolium hydroxide (8). The structures of these products are substantiated using 2D nmr techniques.
Synthesis of 5‐trifluoromethyl‐5,8‐dideazafolic acid and 5‐trifluoromethyl‐5,8‐dideazaisofolic acid
Authors: Singh Shyam K. , Govindan Meledath , Hynes John B. 
Published: March 2009

AbstractThe target folate analogue 5‐trifluoromethyl‐5,8‐dideazafolic acid has been elaborated in a seven‐step reaction sequence beginning with 2‐fluoro‐6‐trifluoromethylbenzonitrile. The bridge‐reversed isomer 5‐trifluoromethyl‐5,8‐dideazaisofolic acid was prepared in six steps using the common intermediate 2,6‐diamino‐3,4‐dihydro‐4‐oxo‐5‐trifluoromethylquinazoline. The key intermediate 2‐amino‐3,4‐dihydro‐4‐oxo‐5‐trifluoromethyl‐quinazoline was prepared using two distinct synthetic routes and the resulting products were found to be identical.
Synthesis of various 5‐substituted uracils
Authors: Peters Dan , Hörnfeldt Anna‐Britta , Gronowitz Salo 
Published: March 2009

AbstractSeveral Pd‐catalyzed coupling reactions have been evaluated for the synthesis of 5‐substituted uracils. A convenient reaction, further developed by us, is the Suzuki Pd(0)‐catalyzed coupling between arylboronic acids and aryl bromides or iodides in weakly alkaline medium. However, all attempts to use 5‐bromo‐ or 5‐iodouracil as the aryl halide failed. On the other hand, couplings between 2,4‐di‐t‐butoxy‐5‐bromopyrimidine and various arylboronic acids were successful. In cases when the arylboronic acids were not available, it was better to reverse the coupling functionalities and use 2,4‐di‐t‐butoxy‐5‐pyrimidineboronic acid and arylbromides. A large number of 5‐aryluracils were prepared in this way. They were obtained in almost quantitative yields by dealkylation of the 5‐aryl‐2,4‐di‐t‐butoxypyrimidines. However, a great drawback of these procedures is the highly allergenic properties of 2,4‐dichloro‐5‐bromopyrimidine, which is an intermediate in the synthesis of 2,4‐di‐t‐butoxy‐5‐bromopyrimidine and 2,4‐di‐t‐butoxy‐5‐pyrimidineboronic acid. In order to avoid this intermediate the coupling between 5‐bromo‐2,4‐ditrimethylsilyloxypyrimidine and arylboronic acids were attempted but failed. Also attemptes to prepare 2,4‐di‐trimethylsilyloxy‐5‐pyrimidineboronic acid failed due to migration of a silyl group to the 5‐position upon halogen‐metal exchange. We therefore turned to the use of tin derivatives instead of boronic acids in the coupling reaction, which can be carried out under neutral conditions. Thus 5‐(1‐methyl‐2‐pyrrolyl)uracil, which could not be prepared from 2‐bromo‐1‐methylpyrrole and 2,4‐di‐t‐butoxy‐5‐pyrimidineboronic acid was obtained through the Pd(0)‐catalyzed coupling of 1‐methyl‐2‐trimethylstannylpyrrole and 2,4‐di‐t‐butoxy‐5‐bromopyrimidine followed by dealkylation. However, the great advantage with the tin derivatives was that 5‐bromo‐2,4‐ditrimethylsilyloxypyrimidine could be used in the coupling with aryltin derivatives giving 5‐aryluracils in reasonable yields. We also tried to use unprotected 5‐halouracils in the coupling reactions. We were unsuccessful with the 5‐bromo derivative. However, with 5‐iodouracil coupling was achieved in some cases.
An improved procedure for the preparation of 1‐benzyl‐1H‐1,2,3‐triazoles from benzyl azides
Authors: Cottrell Ian F. , Hands David , Houghton Peter G. , Humphrey Guy R. , Wright Stanley H. B. 
Published: March 2009

AbstractA procedure for the preparation of substituted 1‐benzyl‐1H‐1,2,3‐triazoles from benzyl azides under very mild conditions is described. The method provides improved yields and extends the scope of the Dimroth Reaction to other types of active methylene compound to those previously used. Benzyl azides react with active methylene compounds in dimethyl sulphoxide catalysed by potassium carbonate at 35–40° to give 1H‐1,2,3‐triazoles usually in good yield. Acetonitrile derivatives gave 5‐amino‐1H‐1,2,3‐triazoles whereas diethyl malonate gave 5‐hydroxy‐1H‐1,2,3‐triazoles. 1H‐1,2,3‐Triazole‐4‐carboxylate esters and 1H‐1,2,3‐triazole‐4‐ketones were obtained from ethyl acetoacetate and β‐diketones respectively. Benzyl methyl ketone reacted to give a 5‐methyl‐4‐phenyl‐1H‐1,2,3‐triazole, but acetone and acetophenone failed to react. Other active methylene compounds which did not react under these reaction conditions included ethyl cyanoacetate, ethyl fluoroacetate and ethyl nitroacetate.
Photoreaction of benzofuroxan
Authors: Hasegawa Minoru , Takabatake Tohru 
Published: March 2009

AbstractBenzofuroxan 5, upon irradiation using a high pressure mercury lamp with a Pyrex filter in acetonitrile containing a little water, afforded 1H‐azepine‐2,7‐dione 6. The initial stage of this reaction would be formation of a highly reactive intermediate possessing two nitrile oxide functions. On the other hand, when compound 5 was irradiated using a low pressure mercury lamp in acetonitrile containing a little water, it afforded 6H‐furazano[4,5‐c]carbazole 3‐oxide 11 and compound 6. The structure of compound 11 was determined by an X‐ray structural analysis. In the presence of an aromatic hydrocarbon, the formation of compound 11 was decreased and that of compound 6 was increased. Mechanistic studies on the photoreaction suggest that the photosensitized formation of compound 6 with the aromatic hydrocarbon may be carried out by the reabsorption of the fluorescence of it near 365 nm and the presence of it may quench the formation of compound 11.
Pyrazine nucleoside analogs. Synthesis and reactions of some 5‐thio‐substituted pyrazines
Authors: Tuntiwachwuttikul Pittaya , Bardos Thomas J. , Bobek Miroslav 
Published: March 2009

Abstract5‐Benzylthio‐1,2‐dihydro‐2‐oxopyrazine (8) was prepared from 2‐amino‐5‐bromopyrazine by sequential treatment with sodium thiobenzylate and diazotization. Condensation of the silyl derivative of 8 with a protected 2‐deoxyribofuranosyl chloride gave α and β anomers of 5‐benzylthiopyrazine nucleosides. Reaction of 2,5‐dichloropyrazine 4‐oxide with sodium thiobenzylate followed by hydrolysis gave 5‐benzylthio‐1,2‐dihydro‐2‐oxopyrazine 4‐oxide (16).
Synthesis of vertical‐type bis(pyridodipyrimidines) as a redox catalyst and their autorecycling oxidation of alcohols
Authors: Yamato Hirotake , Nagamatsu Tomohisa , Yoneda Fumio 
Published: March 2009

AbstractCondensation of bis(3‐methyluracil‐6‐ylamino)alkanes with 6‐chloro‐5‐formyl‐3‐methyluracil or 2,4,6‐trichloropyrimidine‐5‐carbaldehyde in acetic acid gave the respective bis(pyridodipyrimidin‐10‐yl)alkanes (vertical‐type bis(pyridodipyrimidines)). The vertical‐type bis(pyridodipyrimidines) exhibited autorecycling turnover oxidation toward cyclopentanol and l‐menthol to give the corresponding carbonyl compounds.
An alternative preparation of the 2‐dimethylaminomethylene‐1,3‐bis(dimethylimmonio)propane salt from phosphonoacetic acids and some applications in heterocyclic synthesis
Authors: Gupton John T. , Gall John E. , Riesinger Steve W. , Smith Stanton Q. , Bevirt Kathy M. , Sikorski James A. , Dahl Maria L. , Arnold Zdenek 
Published: March 2009

AbstractAn alternative preparation of a 2‐iminovinamidinium salt from phosphonoacetic acids is described along with its application to the synthesis of 5‐formylpyrimidines and masked 4‐formylpyrazoles.
Synthesis of 7‐(alkenyl, cycloalkenyl, and 1,2,3,6‐tetrahydro‐4‐pyridinyl)quinolones
Authors: Kiely John S. , Laborde Edgardo , Lesheski Lawrence E. , Bucsh Ruth A. 
Published: March 2009

AbstractA series of 1‐cyclopropyl‐1,4‐dihydro‐4‐oxoquinolines was prepared in which the C‐7 position is substituted with a vinyl, a 1‐cyclopentenyl, or a 1,2,3,6‐tetrahydro‐4‐pyridinyl group. These quinolones were synthesized via a palladium‐catalyzed cross coupling of a 7‐quinolyltriflate with an appropriately functionalized vinylstannane.
An improved synthesis of pyrroles from N‐p‐toluenesulfonylglycine esters and α,β‐unsaturated aldehydes and ketones
Authors: Lash Timothy D. , Hoehner Michael C. 
Published: March 2009

AbstractN‐p‐Toluenesulfonylglycine esters 2 condensed with α,β‐unsaturated carbonyl compounds 1 in the presence of the non‐nucleophilic base DBU to give hydroxypyrrolidines 3. Dehydration with phosphorus oxychloride‐pyridine, followed by DBU mediated elimination of p‐toluenesulfinic acid, gave a series of synthetically useful pyrrole‐2‐carboxylates 5.
Synthesis, stereochemistry and pharmacological activity of rac.‐cis‐tetrahydro‐6‐hydroxy‐7‐(4‐methoxyphenyl)‐1,4‐thiazepin‐5(2H)‐ones
Authors: Mohacsi Erno , O'Brien Jay P. , Todaro Louis J. 
Published: March 2009

AbstractReaction of 2‐aminoethanethiol (3) withtrans‐3‐(p‐methoxyplienyl)glycidate (4) gave the rac.‐cis‐1,4‐thiazepinone5and a by‐product6. The structure of5was proven by X‐ray crystallography. The X‐ray data revealed that this compound adopts the chair conformation in the solid state and the heterocyclic ring is sevenmembered. The structure of the by‐product6was elucidated on the basis of spectral data. Compounds9and10were inactive as calcium channel blocking agents.
A comparative study on the synthesis of pyrazolo‐[4,3‐c]quinoline oxides by reductive cyclisations
Authors: Sicker Dieter 
Published: March 2009

AbstractAlternate routes for the reductive cyclisation of 4‐acetyl‐3‐methyl‐5‐(2‐nitrophenyl)‐1‐phenylpyrazole under different conditions are described. Whereas 3,4‐dimethyl‐1‐phenylpyrazolo[4,3‐c]quinoline 5‐oxide is formed by mild noncatalytic reductions, catalytic and transfer hydrogenation processes cause the diastereoselective formation of cis‐4,11‐dihydro‐3,5‐dimethyl‐1‐phenylpyrazolo[4,3‐c]quinoline 6‐oxide.
Synthesis of pyrrolopyridines (azaindoles)
Authors: Mahadevan Indumathy , Rasmussen Malcolm 
Published: March 2009

AbstractImproved, convenient, and reliable routes for the synthesis of 4‐, 5‐, 6‐, and 7‐azaindole, 7‐methyl‐4‐azaindole, 7‐methyl‐6‐azaindole, and the hitherto unreported 7‐amino‐4‐azaindole are described. The syntheses have been accomplished either by significant modifications to established procedures or by new methods which afford the compounds in improved yields.
Synthesis of 7‐methyl‐4,6,6a,7,10,10a‐hexa‐hydroindolo[4,3‐fg]quinazoline derivatives
Authors: Mantegani Sergio , Bandiera Tiziano , Brambilla Enzo , Traquandi Gabriella 
Published: March 2009

AbstractThe synthesis of a series of compounds indolo[4,3‐fg]quinazoline related to ergoline (indolo[4,3‐fg]quinoline) is reported. The key step of the synthetic sequence is the ring cleavage of the ketone IV. The stereochemistry of the chiral centers is established by the chirality of dihydrolysergic acid I.
Inverted and suppressed direct response HMQC‐TOCSY spectra ‐ a convenient method of spectral editing
Authors: Martin Gary E. , Spitzer Timothy D. , Crouch Ronald C. , Luo Jiann‐Kuan , Castle Raymond N. 
Published: March 2009

AbstractHMQC‐TOCSY spectra provide a convenient means of establishing proton‐proton connectivities in congested spectra of complex aromatic heterocycles. Advantage is taken of the greater dispersion of the 13C nmr spectrum to circumvent overlap which would preclude spectral interpretation through the usual COSY spectrum. A recently reported method for inverting direct responses (IDR) in HMQC‐TOCSY spectra is demonstrated for [1]benzothieno[2,3‐c]naphtho[2,1‐g]quinoline. A modification of the IDR‐HMQC‐TOCSY method is also demonstrated which is capable of fully suppressing direct responses (SDR) without resorting to the timing of the onset of decoupling as in the original report of the HMQC‐TOCSY experiment. SDR‐HMQC‐TOCSY has the further advantage of allowing the use of higher levels of digitization in F2 than can be attained when broadband heteronuclear decoupling is employed.
Synthesis of 5‐fluoro‐2‐methyl‐3‐(2‐trifluoromethyl‐1,3,4‐thiadiazol‐5‐yl)‐4(3H)‐quinazolinone and related compounds with potential antiviral and anticancer activity
Authors: Párkányi Cyril , Yuan Hui Liang , Strömberg Bo H. E. , Evenzahav Ariella 
Published: March 2009

AbstractThe synthesis of ten new substituted 1,3,4‐thiadiazolyl‐4(3H)‐quinazolinones 8–11, 13, 17, and 20–23 is reported. Compounds 8–11 were prepared by condensation of 5‐fluoro‐2‐methyl‐3,1‐benzoxazin‐4‐one (3) and 5‐substituted 2‐amino‐1,3,4‐thiadiazoles 4–7. Compound 13 was obtained by condensation of 5‐fluoro‐2‐methyl‐3,1‐benzoxazin‐4‐one (3) with DL‐α‐amino‐ϵ‐caprolactam (12). Compound 17 was synthesized by condensation of 6‐bromo‐2‐methyl‐3,1‐benzoxazin‐4‐one (16) and 2‐amino‐5‐t‐butyl‐1,3,4‐thiadiazole (5). Compounds 20–23 were obtained by condensation of 5‐chloro‐6,8‐dibromo‐2‐methyl‐3,1‐benzoxazin‐4‐one (19) and 5‐substituted 2‐amino‐1,3,4‐thiadiazoles 4–7, respectively. The substituted 3,1‐benzoxazin‐4‐ones 3, 16, and 19 were obtained in good yield by refluxing the appropriate anthranilic acid, 1,15, and 18 with acetic anhydride (2).
Synthesis of pyrido[1′,2′:1,2]imidazo[4,5‐b]quinoxalines
Authors: Tanaka Kiyoshi , Takahashi Hideki , Takimoto Kozo , Sugita Masahiko , Mitsuhashi Keiryo 
Published: March 2009

AbstractSynthesis of pyrido[1′,2′:1,2]imidazo[4,5‐b]quinoxalines by the facile cyclizations of 2,3‐dichloroquinoxalines with 2‐aminopyridines and of 2‐amino‐3‐chloroquinoxalines with various substituted pyridines is described.
Investigation of the synthesis and analgesic activity of 1‐substituted 4‐(propananilido)perhydroazepines
Authors: Deruiter Jack , Andurkar Shridhar , Riley Thomas N. , Walters Donald E. , Noggle F. Taylor 
Published: March 2009

AbstractMethods are explored to enhance the efficiency and versatility of the synthesis of the 1‐substituted 4‐(propananilido)perhydroazepine analgesics. The modified synthesis begins with ring expansion of 1‐carbethoxy‐4‐piperidinone3with ethyl diazoacetate and boron trifluoride to yield 1,5‐biscarbethoxyperhydroazepin‐4‐one4. Selective hydrolysis of4followed by decarboxylation provides 1‐carbethoxyperhydroazepin‐4‐one6. Reductive amination of6with aniline affords the 4‐anilino intermediate7which is treated with propionic anhydride to give 1‐carbethoxy‐4‐(propananilido)perhydroazepine18. Selective cleavage of the 1‐carbethoxy group of 18 was accomplished with trimethylsilyliodide to yield the versatile intermediate 4‐(propananilido)‐perhydroazepine 19. Treatment of 19 with styrene oxide afforded the 1‐[2‐(1‐hydroxy‐1‐phenyl)ethyl] derivative1cwhich, in the tail‐flick assay, displays greater analgesic potential than previously reported members of this series.