bluuebunny/crossref_metadata_2025 huggingface dataset:
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

Three 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

Some 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

Novel 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

A 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.
The synthesis of naphthothiopyranopyranones and naphthothiopyranopyranthiones
Authors: Takido Toshio , Tomizawa Nobuyuki , Tsukano Kazuo , Hayashi Takao , Itabashi Kunio
Published: March 2009

The synthesis of fused tetracyclic naphthothiopyranopyranones from dihydronaphthothiopyranones I or II has been studied. Compounds I or II have been cyclised in good yield to the corresponding dioxaborin difluoride complexes III, IV, XIII and XIV by treatment with acetic or propionic anhydride and boron trifluoride etherate. These complexes and the Vilsmeier reagent reacted to produce fused tetracyclic 3‐substituted naphthothiopyranopyranones V, VI, XV or XVI.

The reaction of dioxaborin difluoride complexes III or IV with dimethylthioformamide (DMTF) afforded dimethylaminovinyldioxaborin difluoride complexes IX or X. Treatment of IX or X with hydrochloric acid solution gave naphthothiopyranopyranones VII or VIII.

The reaction of VII, VIII, XV or XVI with DMTF/acetic anhydride yielded new products, which was identified as naphthothiopyranopyranthions XI, XII, XVII or XVIII.
Synthesis of novel substituted spirohydantoins
Authors: Carrera George M. , Garvey David S.
Published: March 2009

The synthesis of novel N‐1‐alkylspirohydantoins (1‐alkyl‐1,3,8‐triazaspiro[4.5]decanes) is reported. The key hydantoin intermediates 3 were prepared using standard hydantoin methodology. This synthesis allows for differential substitution of all three nitrogens.
The meyer‐schuster rearrangement and hydrohalide addition of 3‐alkynyl‐3‐hydroxy‐1H‐isoindol‐1‐ones
Authors: Omar Enouri A. , Tu Chi , Wigal Carl T. , Braun Loren L.
Published: March 2009

Treatment of N‐methyl and N‐phenylphthalimide with appropiate lithium acetylides in tetrahydrofuran obtained the acetylenic alcohols 2a through 2h. These compounds, when subjected to mildly acidic hydrolysis conditions in aqueous organic solvents, underwent Meyer‐Schuster rearrangement to yield the α,β‐unsaturated carbonyl compounds 4a through 4h which were determined to have the E configuration. The phenyl ethynyl analogs of series 4 underwent hydrohalide addition when treated with hydrogen halides in water solution.
New synthesis of 4,5‐dihydro‐1,2,4‐triazin‐3(2H)‐one derivatives through cyclic transformation of 1,3,4‐oxadiazol‐2(3H)‐one derivatives
Authors: Milcent René , Yver Béatrice , Barbier Géo
Published: March 2009

Some 5‐aryl(or benzyl)‐2‐oxo‐1,3,4‐oxadiazole‐3(2H)‐acetones or acetophenones 2 were easily prepared. These compounds reacted with hydrazine derivatives to give 4,5‐dihydro‐1,2,4‐triazin‐3(2H)‐one derivatives 3, 4 and 6 in good yields. With phenylhydrazine, the intermediate hydrazones 5 were obtained. Their conversion into triazinones necessitated the presence of sodium ethylate.
Conformational analysis of benzoannulated nine‐membered rings. Part 3. 1,4,5,7‐Tetrahydro‐3H‐2,6‐benzodiselenine and its 4‐spiro derivatives
Authors: Rys Barbara , Duddeck Helmut , Hiegemann Monika
Published: March 2009

The 1H and 13C nmr spectra of 1,4,5,7‐tetrahydro‐3H‐2,6‐benzodiselenine (1) and three 4‐spiro derivatives 2–4 as well as the 77Se nmr spectra of 2 have been recorded at different temperatures in order to investigate their conformational behavior. It was found that in analogy to corresponding dithionins the molecules adopt a chiral ground state conformation (Figure 2), and coalescence effects are due to racemization.
Synthesis of 3‐hetaryl‐4,5,6,7‐tetrahydrobenzo[b]thiophenes
Authors: Sabnis R. W. , Rangnekar D. W.
Published: March 2009

A novel efficient synthesis of 3‐hetaryl‐4,5,6,7‐tetrahydrobenzo[b]thiophenes was achieved by the cyclocondensation of ethyl 2‐amino‐4,5,6,7‐tetrahydrobenzo[6]thiophene‐3‐carboxylate with selected o‐substituted aromatic amines or with alifatic, aromatic and heterocyclic acid hydrazides in the presence of polyphosphoric acid.
A convenient and versatile synthesis of 4‐trifluoromethyl‐substituted pyrazoles
Authors: Meazza Giovanni , Zanardi Giampaolo , Piccardi Paolo
Published: March 2009

Trifluoromethyl‐substituted pyrazoles were synthesized via 1,3‐dipolar cycloaddition from sydnones 2a‐j and 1‐aryl‐3,3,3‐trifluoro‐propynes 5a‐f. The regioselectivity of the reaction and the spectroscopic characteristics of the products are discussed.
New derivatives of 4,4,5,5‐tetramethyl‐4,5‐dihydro‐1‐H‐imidazol‐1‐oxyl 3‐oxide as monomers for polyradicals with special magnetic properties
Authors: Saf Robert , Swoboda Petra , Hummel Klaus , Czaputa Rainer
Published: March 2009

The preparation of new derivatives of 4,4,5,5‐tetramethyl‐4,5‐dihydro‐1H‐imidazol‐1‐oxyl 3‐oxide as monomers for purely organic polymers with special magnetic properties is described. 3,5‐Diethynylbenzaldehyde and 3,5‐bis(trimethylsilylethynyl)benzaldehyde were converted to the corresponding 1,3‐dihydroxy‐4,4,5,5‐tetramethylimidazolidine derivatives which were oxidized to stable nitronyl nitroxide radicals.
Preparation of 3‐hydroxy‐ and 3‐methoxy‐N‐heteroaryl‐2‐methyl‐4‐pyridones
Authors: Jakopčić Krešimir , Mintas Mladen , Isufi Islam
Published: March 2009

A number of new 3‐hydroxy‐ and 3‐methoxy‐2‐methyl‐4‐pyridones substituted on the nitrogen atom with selected heterocycles has been prepared. Novel chelating properties of the hydroxy‐compounds are expected.
Synthesis of 3‐substituted 5‐arylisoxazoles from α,β‐unsaturated oximes
Authors: Alberola Angel , Manuel Bañez J. , Calvo Luis , Rodríguez Rodríguez M. Teresa , Carmen Sañudo M.
Published: March 2009

The synthesis of 3‐substituted 5‐arylisoxazoles from oximes of α,β‐unsaturated ketones is studied. The formation of the isoxazole derivatives takes place by cyclization of oximes in the presence of iodine and potassium iodide. The presence of isoxazoline is detected. On the basis of the results a plausible mechanism is suggested.
Synthesis of a new 1,4‐dihydropyridine containing the imidazo[1,5‐α]pyridine nucleus
Authors: Fos Empar , Boscá Francisco , Mauleón David , Carganico Germane
Published: March 2009

The synthesis of the new dihydropyridine diethyl 1,4‐dihydro‐4‐(imidazo[1,5‐α]pyridin‐8‐yl)‐2,6‐dimethyl‐pyridine‐3,5‐dicarboxylate (1) is described. After many attempts to prepare the key intermediate aldehyde 2a by different approaches, this compound has been obtained in good yields from methyl 2‐cyano‐3‐pyridinecar‐boxylate (10). A three‐step procedure involving reduction to the amine, formylation with concomitant cyclization and reduction of the ester group was used.
Anticancer anthrapyrazoles. The synthesis of 2‐substituted 5‐nitro and 5‐aminoanthra[1,9‐cd]pyrazol‐6(2H)‐ones
Authors: Hollis Showalter H. D. , Turner William R.
Published: March 2009

Synthetic methodologies for the preparation of substituted 5‐nitro‐ and 5‐aminoanthra[1,9‐cd]‐pyrazol‐6(2H)‐ones, 4 and 5 respectively, substituted with a basic side at N‐2 and dioxy substitution in the A‐ring, are reported. These compounds are essentially devoid of activity against in vitro L1210 leukemia and in vivo murine P388 leukemia.
Studies on isocyanides and related compounds. Investigation on the reaction between (Z)‐alkyl 3‐dimethylamino‐2‐isocyanoacrylates and acyl chlorides
Authors: Bossio Ricardo , Marcaccini Stefano , Pepino Roberto , Paoli Paola , Polo Cecilia
Published: March 2009

The reaction between (Z)‐methyl 3‐dimethylamino‐2‐isocyanoacrylate (1a) and acyl chlorides 2a,b did not afford methyl 2‐acyl‐1‐methyl‐1H‐imidazole‐4‐carboxylates 3a,b, as previously reported, but 2‐acyl‐4‐dimeth‐ylaminomethyleneoxazol‐5(4H)‐ones 4a,b.
9,9‐diphenyl‐1,9,10,10a‐tetrahydro‐2H‐phenaleno[1,9‐bc]pyrans
Authors: Beswick John R. , Cotterill W. David , Iqbal Muhammad , Livingstone Robert
Published: March 2009

Reaction between some naphtho[2,1‐b]pyrans and 1,1‐diphenylethene affords 9,9‐diphenyl‐1,9,10,10a‐tetrahydro‐2H‐phenaleno[1,9‐bc]pyrans.
Synthesis of C‐nor‐4,6‐secocamptothecin and related compounds
Authors: Kurihara Takushi , Tanno Hirokatsu , Takemura Shigetaka , Harusawa Shinya , Yoneda Ryuji
Published: March 2009

C‐nor‐4,6‐Secocamptothecin 2, 4‐ethyl‐4‐hydroxy‐6‐(2‐quinolinyl)‐1H‐pyrano[3,4‐c]pyridine‐3,8(4H,7H)‐dione, lacking the C‐ring of camptothecin 1, and its related compounds 3 and 4 were prepared from ethyl quinoline‐2‐carboxylate 7. By an analogous reaction sequences, synthesis of 6‐(2‐pyridinyl)‐1H‐pyrano[3,4‐c]‐pyridine‐3,8(4H7H)‐dione derivatives 5 and 6, which contain the B, D, and E ring of 1, were achieved.
Condensation reactions of activated picolines with anthranilate esters and o‐nitrobenzaldehyde: Improved syntheses of the antiarrhythmic drug encainide
Authors: Dillon John L. , Spector Richard H. , Madding Gary D. , Wire Mary E.
Published: March 2009

Two new and improved syntheses of the antiarrhythmic drug Encainide, 1, are presented. The first approach is based on the condensation of 2‐picolyllithium with the p‐anisoyl amide of methyl anthranilate, 3, followed by a series of catalytic hydrogenations and methylation. The second route relies on a particularly facile condensation reaction between N‐methylpicolinium methyl sulfate and o‐nitrobenzaldehyde to produce the alcohol 17c in high yield which is converted to the olefin 18c by a novel dehydration procedure and then to the final molecule, by catalytic hydrogenation over platinum followed by acylation.
Synthesis and NMR characterization of a novel heterologue of pyrene: The naphtho[1,8‐bc;4,5‐b'c']dipyran (1,8‐dioxapyrene)
Authors: Buisson J.‐P. , Kotzyba J. , Lièvremont J.‐P. , Demerseman P. , Platzer N. , Bideau J.‐P. , Cotrait Michel
Published: March 2009

1,8‐Dioxapyrene, a novel unsubstituted dioxa‐analog of pyrene was synthesized from 4‐methoxy‐1‐naphthol in a ten‐step reaction involving two peri‐heterocyclizations. 1H and 13C nmr indicated a disruption of extended delocalization of π electrons, like that observed with the 1,6‐isomer.
Synthesis of new thienocyclopenta[3,2‐d]‐oxazole and thiazole derivatives
Authors: Dallemagne Patrick , Boulouard Michel , Rault Sylvain , Robba Max
Published: March 2009

Synthesis of thieno[2′,3′:5,4]cyclopenta[3,2‐d]oxazole and thiazole derivatives are achieved by insertion of carbon dioxide and disulfide into 4‐amino‐5‐chloro‐5,6‐dihydro‐4H‐cyclopenta[b]thiophen‐6‐one.
Synthesis of 6‐aminobenzo[b]naphtho[2,1‐d]thiophene
Authors: Tominaga Yoshinori , Castle Lyle W. , Castle Raymond N.
Published: March 2009

6‐Aminobenzo[b]naphtho[2,1‐d]thiophene has been prepared by two different routes, one, a one‐pot synthesis.
Synthesis of 3‐acylamino‐2‐oxazolidinone derivatives through cyclic transformations of 5‐aryl (or benzyl)‐1,3,4‐oxadiazol‐2(3H)‐one derivatives
Authors: Milcent René , Yver Beatrice , Barbier Géo
Published: March 2009

New 3‐acylamino‐2‐oxazolidinone derivatives 3 were obtained in good yields by reaction of 5‐aryl (or benzyl)3‐(2‐hydroxyethyl)1,3,4‐oxadiazol‐2(3H)ones 1 with sodium ethylate. Treatment of ethyl 5‐aryl‐2‐oxo‐1,3,4‐oxadiazole‐3(2H)‐acetates 7 with aromatic aldehydes in the presence of sodium ethylate or sodium hydride afforded 3‐acylamino‐5‐aryl‐4‐ethoxycarbonyl‐2‐oxazolidinone derivatives as two trans‐5 and cis‐6 racemics. Only RS,SR‐racemates were obtained with acetophenone under the same conditions.
Crystal and molecular structure and spectra of 2′,2′,5,5,5′,5′,7,7‐octamethyl‐2′,5,5′,7‐tetrahydrofuro[3,4‐d]‐1‐oxa‐3,4‐disele‐nin‐2‐spiro‐3′‐furan‐4′(3′H)‐one from selenium dioxide oxidation of 2,2,5,5‐tetramethyltetrahydrofuran‐3‐one. A novel six‐membered heterocyclic ring system in the chalcogen series
Authors: Kuronen Pirjo , Laitalainen Tarja , Orama Olli
Published: March 2009

When 2,2,5,5‐tetramethyltetrahydrofuran‐3‐one 1 was oxidized with selenium dioxide in ethanol, the title heterocycle 4 was formed along with 2,2,5,5‐tetramethyltetrahydro‐3,4‐furandione 2. The diselenide 4 represents a novel six‐membered heterocycle in the chalcogen series.
Natural product chemistry. Part 159. Two methods for the synthesis of 4‐azaacronycine as a potential antitumor agent
Authors: Reisch Johannes , Dziemba Peter , La Mura Marco , Rao Akkinepalli Raghu Ram
Published: March 2009

Two different methods for the synthesis of 4‐azaacronycine (10) have been described. One route with a fusion reaction between 1,3‐dihydroxy‐10‐methyl‐9(10H)‐acridinone (1) and 2‐amino‐2‐methyl‐3‐butyne in a glass ampoule and the other by a reaction of 3‐amino‐1‐methoxy‐10‐methyl‐9(10H)‐acridinone (9) with 2‐chloro‐2‐methyl‐3‐butyne.
Investigation into the diastereomeric composition of a pyruvamide dimer
Authors: Stewart Kent D. , Bailey Charles , Hall William R. , Crouch Ronald
Published: March 2009

N‐Benzylpyruvamide cyclized under basic conditions to give a 70:30 trans:cis mixture of diastereomers of N,1‐dibenzyl‐2,4‐dihydroxy‐4‐methyl‐5‐oxo‐2‐pyrrolidinecarboxamide.
Reaction of amines on 3‐ureidomethylenecoumarins. A new route to N‐(methylene‐4‐oxocoumarinyl)amines
Authors: Hamdi Maâmar , Granier Patrick , Sakellariou Reine , Spéziale Vincent
Published: March 2009

N‐(Methylene‐4‐oxocoumarinyl)amines were prepared in good yield by reacting aliphatic and aromatic amines bearing functional groups with the relevant 3‐ureidomethylenecoumarins.
The synthesis of 6,9‐difluorobenzo[g]quinoline‐5,10‐dione. Displacements of the fluorides by diamines which lead to 6,9‐bis[(aminoalkyl)amino]benzo[g]quinoline‐5,10‐diones
Authors: Krapcho A. Paul , Petry Mary E. , Landi John J. , Stallman John , Polsenberg Johanna F. , Hacker Miles P. , Spinelli Silvano , Oliva Ambrogio , Di Domenico Roberto , Menta Emesto
Published: March 2009

The synthesis of 6,9‐difluorobenzo[g]quinoline‐5,10‐dione (3b) is described. Facile ipso substitutions of the fluorides from 3b by diamines readily yield the corresponding 6,9‐bis[(aminoalkyl)amino]benzo‐[g]quinoline‐5,10‐diones 2. The analogue 2d has been synthesized by side arm modifications of dione 8a.
A new approach for the synthesis of fused pyrroles. The synthesis of acyl substituted pyrrolo[1,2‐x]azines
Authors: Čopar Anton , Stanovnik Branko , Tišler Miha
Published: March 2009

N‐Acetonyl‐ and N‐phenacyl quaternary salts of α‐methyl substituted heterocycles 16, 17, 21, 23 and 26 were converted with DMFDMA into the corresponding 3‐acylpyrrolo[1,2‐a]pyridine 18, 7‐benzoylpyrrolo‐[1,2‐c]pyrimidine 22, and 6‐benzoylpyrrolo[1,2‐a]pyrazine derivatives 24 and 27. A concurrent reaction produced methyl and phenyl substituted pyrrolo[1,2‐x]azines 19, 20, 25 and 28.
Reactions of 4‐Methoxy‐3‐quinolinyl and 1,4‐Dihydro‐4‐oxo‐3‐quino‐linyl Sulfides Aiming at the Synthesis of 4‐Chloro‐3‐Quinolinyl Sulfides
Authors: Maślankiewicz Andrzej , Boryczka Stanislaw
Published: March 2009

The preparation of 1,4‐dihydro‐4‐oxo‐3′‐alkylthio‐3,4′‐diquinolinyl sulfides 3 or 1,4‐dihydro‐4‐oxo‐3‐(alkylthio)quinolines 4 by acid catalysed hydrolysis of 4‐methoxy‐3′‐alkylthio‐3,4′‐diquinolinyl sulfides 1 or 4‐methoxy‐3‐(alkylthio)‐quinolines 2 is described. The reactions of 4‐methoxy‐3′‐alkylthio‐3,4′‐diquinolinyl sulfides 1 or 1,4‐dihydro‐4‐oxo‐3′‐alkylthio‐3,4′‐diquinolinyl sulfides 3 with phosphoryl chloride in DMF afforded 4‐chloro‐3′‐alkylthio‐3,4′‐diquinolinyl sulfides 5. Treatment of the title compounds 1 or 3 with boiling phosphoryl chloride systems:leads to 4‐chloro‐3‐(alkylthio)quinolines 6 and thioquinanthrene but those of alkoxy‐ or oxo‐quinolines 2 or 4 lead to 4‐chloro‐3‐(alkylthio)quinolines 6. The reactions of N‐methyl‐4(1H)‐quinolinones 3n and 4n with phosphoryl chloride directed to 4‐chloro‐3‐(alkylthio)quinolines 6 were studied as well.
Heteroarylation of 6‐Aryl‐2,3‐dihydroimidazo[2,1‐b]thiazole with N‐(Ethoxycarbonyl)heteroaromatic Salts
Authors: Shilcrat Susan , Lantos Ivan , Mcguire Michael , Pridgen Lendon , Davis Louisa , Eggleston Drake , Staiger David , Webb Lee
Published: March 2009

The ethyl chloroformate salts of a variety of benzo‐fused six membered π‐deficient heteroaromatics, including quinoline, isoquinoline, 4‐chloroquinoline, 3‐bromoquinoline, phthalazine, and quinazoline, reacted with 6‐aryl‐2,3‐dihydroimidazo[2,1‐b]thiazole at the 5‐position. The dihydroheteroaromatic adducts were oxidized by o‐chloranil, sulfur, or electrochemical methodology to form the 5‐heteroaromatic‐6‐aryl‐2,3‐dihydroimidazo[2,1‐b]thiazoles, 10‐15. In each example, the regiochemistry of addition to the heteroaromatic ring was established.
Synthesis and spectroscopic characterizations of both 4b,5‐dihydro‐4b‐methyl‐11H‐isoindolo[2,1‐a]benzimidazol‐11‐ones and 2,3,3a,4‐tetrahydro‐3a‐methyl‐1H‐pyrrolo[1,2‐a]benzimidazol‐1‐ones
Authors: Louvet Philippe , Thomasson FrançOis , Luu‐Duc Cuong
Published: March 2009

The complete assignment of the 1H and 13C nmr spectra of some derivatives of both 4b,5‐dihydro‐4b‐methyl‐11H‐isoindolo[2,1‐a]benzimidazol‐11‐one I and 2,3,3a,4‐tetrahydro‐3a‐methyl‐1H‐pyrrolo[1,2‐a]‐benzimidazol‐1‐one II was herein reported by the combined use of one and two‐dimensional nmr techniques. Eight compounds, three of which are novel, 2a, 3, 6, were thus prepared. Their uv and ir spectra were also obtained. In addition, the mass spectra of compounds 1, 2a, 2b, 3 and 6 are reported.
Reactions of 4,6‐bis(acetyl)resorcinol with alkoxycarbonylalkylidene(triphenyl)phosphoranes. Preparation of coumarin derivatives
Authors: Nicolaides D. N. , Fylaktakidou K. C. , Bezergiannidou‐Balouktsi C. , Litinas K. E.
Published: March 2009

Reaction of compound 1 with ylide 2a affords compounds 3a, 3b and coumarins 4a, 5a, 5b, 6a in 77% total yield. Reaction of 1 with ylide 2b affords coumarin 4b. The acetylderivatives obtained, react further with ylides 2a‐c to give pyrano[3,2‐g]chromene‐2,8‐diones 6b‐d.
Synthesis of 2,7‐disubstituted‐5,6‐dimethylpyrrolo‐[2,3‐d]‐1,3‐oxazin‐4‐ones as antifungal agents
Authors: Player Mark R. , Sowell J. Walter , Williams Glenn R. , Cowley Gerald T.
Published: March 2009

A series of novel 5,6‐dimethylpyrrolo[2,3‐d]‐1,3‐oxazin‐4‐ones were synthesized from 2‐amino‐3‐tert‐butoxy‐carbonyl‐4,5‐dimethylpyrroles. Two methods were used, cyclodehydration of 2‐acylamino‐3‐carboxypyrroles with acetic anhydride and direct conversion of the 5,6‐dimethylpyrrolo[2,3‐d]‐1,3‐oxazin‐2,4‐diones to the title compounds with an anhydride directly providing the 2 substituent. Molecular modeling techniques revealed that these pyrrolo[2,3‐d]oxazinones were rigid analogues of the allylamine antifungals. The compounds were tested for in vitro activity against Tricophyton and Scopulariopsis sp.
Photodimerization of 1H‐azepine‐2,7‐dione
Authors: Takabatake Tohru , Hasegawa Minoru
Published: March 2009

1H‐Azepine‐2,7‐dione 2 afforded photodimer 8 by irradiation using a high or low pressure mercury lamp. Photodimer 8 had a unique structure which must have formed with the prototropy in one of the two molecules of compound 2. Measurement of the fluorescence spectra of 2 indicated a spectrum of the excimer during the dimerization of 2. Irradiation of the dimer of 2 at its wave‐length of maximal absorption failed to cause it to change into a monomer of 2.
Structures of abnormal‐ and normal‐addition 1‐pyrazolines produced from 2‐cyano‐3,3‐di‐(or mono‐)‐substituted‐acrylates with diazoalkanes
Authors: Nagai Wakatu , Hirata Yumiko , Hosomi Keiji , Higuchi Taiichi
Published: March 2009

Reactions of methyl 2‐cyano‐3‐methyl‐3‐(p‐substituted‐phenyl)acrylates (1) with 1‐phenyldiazoethane (2) produced the stable abnormal‐addition 1‐pyrazolines, AP, 4 [1]. The structure of cis‐syn‐4a (X = NO2) was determined by X‐ray crystallography. Thermal decomposition of 4 results in “true cycloreversion” to the starting materials. Stereochemistry and decomposition of the normal‐addition 1‐pyrazolines, NP, produced in situ from 2‐cyano‐3‐(p‐substituted‐phenyl)acrylates and diazoalkanes, are also discussed.
Synthesis of c‐17 trans β‐lactams of the androstane series
Authors: Siddiqui A. U. , Satyanarayana Y. , Srinivas M. , Siddiqui A. H.
Published: March 2009

3,3′‐Ethylenedioxyandrost‐4‐en‐17β‐ol 1 was converted into the ethyl ester 2 by reaction with potassium metal and ethyl chloroacetate. The ethyl ester 2 on reaction with hydrazine gave the hydrazide 3. Condensation of 3 with aryl aldehydes gave the Schiff bases 4. The reaction of Schiff bases 4 with mono‐chloroacetyl chloride in the presence of triethylamine afforded the β‐lactams 5.
Synthesis of benzyl and tert‐butyl 3‐(2‐methoxycarbonylethyl)‐4‐methylpyrrole‐2‐carboxylates from methyl 4‐oxobutanoate
Authors: Drinan Martin A. , Lash Timothy D.
Published: March 2009

Condensation of methyl 4‐oxobutanoate with nitroethane in the presence of 4‐dimethylaminopyridine, followed by treatment with acetic anhydride, afforded a nitroacetoxyester 10b. Subsequent reaction with isocyanoacetate esters and DBU in refluxing tetrahydrofuran gave the synthetically valuable pyrroles 1a and 1b.
Synthesis of a novel cyclic sulfone dihydropyridine: An investigation of the isomerization reaction converting an exocyclic double bond isomer into a 1,4‐dihydropyridine
Authors: Fenk Christopher J. , Conley Richard A. , Lindabery Gregory C. , Stefanick Stephen M. , Royster Thomas E. , Dodd John H. , Schwender Charles F.
Published: March 2009

An eight membered cyclic sulfone 1,4‐dihydropyridine, RWJ 22726, 1, with remarkable cardiovascular activity was prepared by isomerization of an exocyclic double bond isomer using various reaction conditions. Under acidic and thermal isomerization conditions, an equilibrium mixture of products in an optimum ratio of 1:3.5 in favor of the desired 1,4‐dihydropyridine was obtained. Equilibration using basic reaction conditions could not be effected. Complete conversion to the 1,4‐dihydropyridine during the isomerization reaction was ultimately achieved by selective precipitation of the hydrochloride salt of the desired isomer.
Intramolecular [4 + 2] cycloaddition reactions of pyridazino‐[4,5‐d]pyridazines with acetylenic side‐chain dienophiles: Synthesis of f‐annelated phthalazines
Authors: Haider Norbert , Loll Claudia
Published: March 2009

Starting from the thione 1, a series of 1‐(alkynyl‐X)‐4‐phenylpyridazino[4,5‐d]pyridazines 4–8 (X = 0, NH, S) was prepared. Thermally induced intramolecular [4+2] cycloaddition reactions of the ethers 4, 5 and the thioether 8 afforded f‐annelated phthalazine derivatives.
3‐(Thiazolidin‐3‐yl)rhodanines. A novel class of rhodanine derivatives
Authors: Hanefeld Wolfgang , Schlitzer Martin
Published: March 2009

α‐Bromoacetylaminorhodanines 1 were reacted with NH4SCN yielding 3‐(thiazolidin‐3‐yl)rhodanines 4, a novel type of rhodanine derivatives bearing a uncommon N‐N ring‐connection.
Condensations of brominated products of o‐acetylbenzophenone with several primary amines
Authors: Nan'Ya Seiko , Ishida Hirofumi , Moiji Ester J. , Butsugan Yasuo , Bajji Ashok C.
Published: March 2009

2‐Bromo‐3‐phenylinden‐1‐one 2 reacted with phenylthiourea to produce 2‐phenylimino‐8‐phenylindeno[1,2‐d]thiazole (heteropentalene) 4 in moderate yield and bis‐substituted‐indenyl sulfide 5 in low yield. Whereas, from the reaction of 2 with thiourea or its methyl derivative only 5 was obtained in moderate yield. Another brominated compound, dibromoacetylbenzophenone and several primary amines afforded iminoindanone derivatives 6.
Synthesis and mass spectra of some 1‐aroylamino‐5‐arylaminomethyl‐1,2,3‐triazoles
Authors: Laskos Efstathios , Lianis Pygmalion S. , Rodios Nestor A.
Published: March 2009

The title compounds 2 are prepared from the reaction of 1‐(N, N‐diaroyl)amino‐5‐bromomethyl‐1,2,3‐triazoles with aromatic amines. The fragmentation pattern upon electron impact at 70 eV of compounds 2 is studied. The molecular ion peak is present in all the spectra examined. Besides the [M‐28]++, there is also a more abundant [M‐29]+ peak, corresponding to a N2H loss of the molecular ion. The ion Ar2NH = CH2 is the base or the most prominent peak.
Synthesis of 1‐substituted 3‐nitroquinolin‐4(1H)‐ones
Authors: Radl Stanislav , Chan Ka‐Kong
Published: March 2009

A versatile synthetic method for preparing 1‐substituted 3‐nitroquinolin‐4(1H)‐ones from corresponding 2‐fluoro‐α‐nitroacetophenones is demonstrated by the synthesis of 6,7‐difluoro derivatives 7a‐c. The method involves sequential treatment of the starting nitroacetophenone with triethyl orthoformate and the appropriate amine, followed by a nucleophilic cyclization reaction under mild conditions. The C‐7 fluorine atom of 7 can be displaced by cyclic amines. Substituted 6‐fluoro‐7‐(4‐methyl‐1‐piperazinyl)‐3‐nitroquinolin‐4(1H)‐ones 8a‐c were prepared in this way.
Synthesis, structure and mass spectral fragmentation of a series of substituted furazano[3,4‐b]quinoxaline 1‐oxides and their deoxides
Authors: Gallos John K. , Lianis Pygmalion S. , Rodios Nestor A.
Published: March 2009

A series of substituted furazano[3,4‐b]quinoxaline 1‐oxides have been prepared by oxidation of the respective 2,3‐bis(hydroxyimino)‐1,2,3,4‐tetrahydroquinoxalines with nitric acid and their structure was confirmed by means of their nmr spectra. A very rapid equilibrium occurs between their two isomeric N‐oxide forms via the dinitroso equivalent, and the influence of the 6(7)‐substituents on the equilibrium is discussed. These compounds were easily deoxygenated by triphenylphosphine in quantitative yields to the corresponding furazans. The electron impact mass spectra of both of the above series of compounds have also been recorded and their fragmentation pattern is discussed.
Thienoquinolizidinones. Synthesis and rearrangement into new piperidino[1,2‐a][1,3] or [1,4]diazepinones fused to a thiophene ring
Authors: Marchalin Stefan , Decroix Bernard
Published: March 2009

A convenient route to thienoquinolizidinones is described starting from ethyl pipecolinate and suitable halogenomethylthiophenes or 3‐chloromethylbenzothiophene. The Schmidt reaction and the Beckmann rearrangement of oximes of these ketones led to piperidino[1,2‐a][1,3] or [1,4]diarepines fused to a thiophene ring.
Crystal structural determination of ring‐chain tautomers of 1,2,3,4‐tetrahydro‐s‐tetrazines
Authors: Boese R. , El‐Abadelah M. M. , Hussein A. Q. , Abushamleh A. S.
Published: March 2009

1,2,3,4‐Tetrahydro‐1‐methyl‐3‐(p‐bromophenyl)‐4,6‐diphenyl‐s‐tetrazine (3a), exhibiting “ring ⇋ chain” tautomerism in solutions, exists as the ring tautomer in the solid phase, as proved by X‐ray crystal structure determination. However, the 6‐acetyl analogue 3b acquires the chain form in the crystalline state.
Synthesis of 3‐(N‐alkylamino)acetophenones via a benzyne intermediate
Authors: Albright J. Donald , Lieberman Daniel F.
Published: March 2009

Reaction of 2‐(2‐bromophenyl)‐2‐methyl‐1,3‐dioxolane with lithium (1,1‐dimethylethyl)amide, lithium (2,2‐dimethylpropyl)amide, lithium (1,1‐dimethylpropyl)amide gave the corresponding N‐(alkyl)‐3‐(2‐methyl‐1,3‐dioxolan‐2‐yl)benzenamines in moderate yields. 1‐[3‐[(1,1‐Dimethylethyl)amino]phenyl]ethanone (4) was prepared in over 80% yield from 2‐(2‐bromophenyl)‐2‐methyl‐1,3‐dioxolane (2).
The preparation of aryl 1‐(2,6‐dimethylphenyl)‐2‐phenyl‐4‐trifluoromethyl‐5‐imidazolyl sulfides and sulfones
Authors: Egolf Roger A. , Bilder Donna M.
Published: March 2009

A series of aryl 1‐(2,6‐dimethylphenyl)‐2‐phenyl‐4‐trifluoromethyl‐5‐imidazolyl sulfides was prepared by displacement of fluoride from the 5‐position of 1‐(2,6‐dimethylphenyl)‐2‐phenyl‐4‐trifluoromethyl‐5‐fluoroimidazole by substituted thiophenols and by benzyl mercaptan. This displacement reaction occurs much more slowly than the corresponding previously described reactions of 4‐trifluoromethyl‐5‐fluorothiazoles and ‐oxazoles. Several solvent‐base pairs were examined; the reaction was found to work best when dimethyl sulfoxide was used as the solvent and diazabicycloundecene as the base. The sulfides were oxidized to sulfones by treatment with hydrogen peroxide in acetic acid.
Synthesis and NMR assignment of 1,4‐oxathiino[3,2‐c;5,6‐c']diquinoline
Authors: Pluta Krystian
Published: March 2009

1,4‐Oxathiinodiquinoline 3 was obtained in three ways from 1,4‐dithiinodiquinolines 1 and 2 via ring opening‐ring closure reactions with total yield of 19, 46 and 77%. Through‐space interactions between the H‐5quinolinyl atoms and oxygen atom were discussed on the basis of 1H nmr spectrum.
Molecular associations between indolizines and tetracyanoethylene
Authors: Bruni Paolo , Conti Carla , Giorgini Elisabetta , Iacussi Marco , Maurelli Eziana , Tosi Giorgio
Published: March 2009

Spectroscopic, thermodynamic and kinetic properties of molecular interactions between indolizines and tetracyanoethylene are reported. The interactions involved in the complexes are weak as evidenced by the low formation constants. The kinetic behaviour indicates the initial formation of a pI‐complex that is rapidly transformed into a σ‐complex and thereafter into the final adduct(s). Apart from the results obtained by other techniques, infrared data clearly evidence vibrational contributes characteristic of the complexes, the tricyanovinyl derivatives and the tetracyanoethylene radical anion.
Synthesis of novel pyridazine acyclonucleosides
Authors: Cho Su‐Dong , Chung Joo‐Wha , Choi Woo‐Yong , Kim Sung‐Kyu , Yoon Yong‐Jin
Published: March 2009

Some pyridazine acyclonucleosides containing hydroxymethyl and 4‐hydroxybutyl groups as an alkanol side chain were prepared. Nucleophilic displacement of N1‐alkyl‐4,5‐dichloropyridazin‐6‐ones is discussed.
A convenient synthesis of 3‐alkyl‐2,3‐dihydro‐2,4‐dioxo‐6‐phenyl‐, 3‐alkyl‐2,3‐dihydro‐4‐oxo‐6‐phenyl‐2‐thioxo‐, and 3‐alkyl‐2‐arylimino‐2,3‐dihydro‐4‐oxo‐6‐phenyl‐4H‐1,3‐thiazines
Authors: Kim Sung Hoon , Ra Yong Hoon , Lee Yoon Young , Kim Kyongtae , Kim Joong Hyup
Published: March 2009

The reactions of 1‐alkylamino‐1‐alkylthio‐3‐phenylpropene‐3‐thiones 3 with thiophosgene and phosgene in toluene, followed by treatment of the reaction mixture with triethylamine gave 3‐alkyl‐2,3‐dihydro‐4‐oxo‐6‐phenyl‐2‐thioxo‐ 4, 3‐alkyl‐2,3‐dihydro‐2,4‐dioxo‐6‐phenyl‐4H‐1,3‐thiazines 5, respectively in good to excellent yields. Similarly treatment of compounds 3 with N‐arylimidoyl dichloride in benzene at room temperature gave 3‐alkyl‐2‐arylimino‐2,3‐dihydro‐4‐oxo‐6‐phenyl‐4H‐1,3‐thiazines 6 in excellent yields. The reactions of compounds 3 with oxalyl chloride in toluene gave also 5 in good yields.
Synthesis, structure, and NMR characterization of a novel [3.3] metacyclophane
Authors: Doyle Timothy J. , Haseltine John
Published: March 2009

The synthesis and crystal structure of metacyclophane 2 are reported. The nmr data relevant to conformational properties are also presented.
Synthesis and spectral properties of 6,7‐dimethoxy‐1‐[(ortho; and para‐R)‐phenyl]‐3,4‐dihydroisoquinoline
Authors: Cortés Eduardo Cortés , Romero Eduardo Cortés , Ramírez Felipe Gutiérrez
Published: March 2009

The preparation of eleven novel 6,7‐dimethoxy‐1‐[(ortho, and para‐R)‐phenyl]‐3,4‐dihydroisoquinolines with possible pharmacological activity is described. The structure of all products was corroborated by ir, 1H‐nmr, 13C‐nmr, and ms.
The utility of the PM3 method for predicting the reactivities of cyanoethenes in diels‐alder reactions with pyrrole
Authors: Jursic Branko S. , Zdravkovski Zoran
Published: March 2009

The reliability of PM3 for predicting the reactivity of cyanoethenes in Diels‐Alder reactions with pyrrole was tested. Using frontier orbital theory it was predicted that the reaction is LUMO dienophile controlled, and the reaction should be facilitated in comparison to cyclopentadiene additions (pyrrole has higher HOMO energy). The transition structures were generated and compared with similar ones generated with both ab initio and PM3 calculations for cyclopentadiene additions: The geometries of the transition structures are similar, although the new CC forming bonds are 2–6% shorter, and the degree of asynchronicity is higher. The prediction of the activation barriers with the PM3 method failed totally. The preferred exo isomer in each case, indicated that the predicted stereoselectivity was incorrect. The prediction of the relative reactivity was also unreliable. Qualitative analyses of similar series of compounds can be obtained by frontier orbital energy correlations. All conclusions were made on the assumption that the reaction is concerted, which does not exclude the possibility that PM3 might be able to predict reliable reaction barriers if some other mechanisms are considered.
A new route to arglecin by metalation and cross coupling of pyrazines. Metalation of diazines. XII
Authors: Turck A. , Plé N. , Dognon D. , Harmoy C. , Quéguiner G.
Published: March 2009

The metalation of dihalogeno and halogenomethoxypyrazines was performed. The resulting pyrazines were submitted to a cross‐coupling reaction with propargyl alcohol followed, after dehydration, by a catalytic reduction. This gives a new route to the synthesis of a key intermediate in the synthesis of arglecin.
Structural aspects of the product from glyoxal and tetrakis(ethoxycarbonylamino)ethane
Authors: Crist Delanson R. , Li Chung‐Hua , Hammer Charles F. , Nelson Keith A. , Adolph Horst G.
Published: March 2009

The base‐promoted addition of glyoxal to 1,1,2,2‐tetrakis(ethoxycarbonylamino)ethane in DMF gives a product mixture containing mostly 1,1′,3,3′‐tetrakis(ethoxycarbonyl)‐4,4′,5,5,'‐tetrahydroxy‐2,2′‐biimidazolidyl. An alternate structure containing a tetraazadecalin system was considered less likely, since the most significant peak in the mass spectrum of this product and a tetraacetate derivative corresponded to half the mass of the parent ion. Two‐dimensional nmr spectra on the major hplc fraction are more consistent with the biimidazolidinyl structure (very low Jvic and lack of NOE enhancement). A HETCOSY spectrum on the mixture allowed assignment of 1H nmr shifts.
Synthesis and a UV and IR spectral study of some 2‐aryl‐Δ‐2‐1,3,4‐oxadiazoline‐5‐thiones
Authors: Charistos D. A. , Vagenas G. V. , Tzavellas L. C. , Tsoleridis C. A. , Rodios N. A.
Published: March 2009

Twenty four 2‐Aryl‐Δ‐2‐1,3,4‐oxadiazoline‐5‐thione derivatives 2 were synthesized and their uv and ir spectra were studied. Correlation between σ‐Hammett constants of aryl substituents and the differences in absorption maxima (Δv = v1‐v2 in kK) of the electronic spectra of the deprotonated species were also evaluated. A new method for the synthesis of the 2‐(amino)aryl derivatives 2v,w,x is also reported.
A comparison of phenylboronic acid and phenyltrimethyltin in the palladium‐catalyzed arylation of 1,5‐dialkylimidazoles
Authors: Wang Dongmei , Haseltine John
Published: March 2009

A comparison of phenyltrimethyltin vs. phenylboronic acid in the palladium‐catalyzed arylation of brominated 5‐methyl‐1(phenylmethyl)imidazoles is described.
Macrocyclic polyesters. II. The preparation of diester diamide macrocycles containing the 2‐aminobutanol sub‐units as potential antimicrobial agents
Authors: Anchisi Carlo , Fadda Anna Maria , Maccioni Anna Maria , Maccioni Elias , Sinico Chiara
Published: March 2009

This paper reports the synthesis of a novel class of diester diamide macrocycles containing 2‐aminobutanol sub‐units, by reacting diacyl dichloride with the aminoalcohol or its oxazastannolane derivatives. The structure of the possible isomers was assigned by spectroscopic and analytical data and, when possible by comparison with samples prepared otherwise.

The ms spectra of these compounds have been studied and the fragmentation patterns and structures of the main ions are described.
Synthesis and structure of new substituted 2‐dicyanomethylene‐1,2‐dihydropyridines
Authors: Fuentes Luis , Márquez César , Contreras Ma Carmen , Lorenzo Ma Jesús , Fonseca Isabel , Sanz‐Aparicio Juliana , Balcazar José L.
Published: March 2009

The synthesis of substituted 2‐dicyanomethylene‐1,2‐dihydropyridines 3b‐c and 2‐dicyanomethylene‐2,3,4,5‐tetrahydropyridine 4 is accomplished from malononitrile dimer and propenenitriles 2. All structures were determined by nmr techniques; however to put our structural assignment for 6‐amino‐3‐cyano‐5‐ethoxycarbonyl‐2‐dicyanomethylene‐1,2‐dihydropyridine 3d on a firm and unequivocal basis we decided to perform X‐ray diffraction analysis of this compound.
On the selectivity in the bromination of selenophene‐2‐carbonyl derivatives in the presence of aluminum trichloride
Authors: Antonov Dmitry N. , Belen'Kii Leonid I. , Gronowitz Salo
Published: March 2009

Bromination reactions of 2‐selenophenecarbaldehyde and 2‐acetylselenophene in the presence of aluminum trichloride have been investigated and the reactivity and positional selectivity compared with those of the analogous thiophene derivatives.
Enolethers. XX. Synthesis of azepino[4,5‐b]quinoxalines and pyridopyrazino[2,3‐d]azepines
Authors: Bonacorso Helio Gauze , Mack Karl‐Ernst , Effenberger Franz
Published: March 2009

1,6‐Diethoxy‐1,5‐hexadiene‐3,4‐dione (1) reacts with primary amines 3 and ammonia respectively in a molar ratio of 1:1 to give mainly aminoalkyl‐ and small amounts of bis(aminoalkyl)‐1,5‐hexadiene‐3,4‐diones 4 and 2, respectively. On heating in dichlorobenzene above 150° the mixtures of 2 and 4 cyclize to yield 1‐alkyl‐1H‐azepine‐4,5‐diones 5 by elimination of ethanol or amine. 3H‐3‐Alkylazepino[4,5‐b]‐quinoxalines 7, 8, 10 and 12 are easily accessible by condensation of the diketones 5a and b with various substituted o‐phenylenediamines 6, 9 and 3,3′,4,4′‐tetraaminobiphenyl (11) in p‐xylene or n‐butanol. 8‐Isopropylpyridopyrazino[2,3‐d]azepines 14 were obtained by condensation of 5b with pyridinediamines 13 in p‐xylene. The azepine‐4,5‐diones 5a‐c can be hydrogenated selectively by sodium borohydride in ethanol at room temperature to give the azepin‐4‐ol‐5‐ones 15a‐c.
Synthetic approaches to 2‐substituted 1‐oxo‐ and 3‐oxotetrahydroisoquinolines
Authors: Cheng Chen‐Yu , Tsai Hui‐Bing , Lin Mei‐Shan
Published: March 2009

2‐Substituted homophthalimides 2a‐c were reduced regioselectively with sodium borobydride to carbinol‐lactam intermediates 3a‐c, which were dehydrated, followed by hydrogenation, to give 1‐oxo‐tetrabydroisoquinolines or 3,4‐dihydroisoquinolin‐1(2H)ones 5a‐c. The isomeric 3‐oxo‐tetrahydro‐isoquinolines or 1,4‐dihydroisoquinolin‐3(2H)‐ones 8a‐i were obtained in satisfactory yields via heating 3‐isochromanone (6) with the corresponding amines 7a‐i in the presence of aluminum chloride.
A new synthetic approach for imidazo[1,2‐a]imidazoles and pyrrolo[1,2‐a]imidazoles
Authors: Kolar Patrik , Tišler Miha
Published: March 2009

Substituted pyrrolo[1,2‐a]imidazoles and imidazo[1,2‐a]imidazoles are prepared in a simple one pot reaction sequence from esters of heterocyclic or aromatic α‐amino acids. The reaction involves condensation with acetoine followed by cyclization with either malonodinitrile, ethyl cyanoacetate or cyanamide.
Saturated heterocycles. Part 216. Synthesis, structure and ring opening of trans‐perhydro‐1,4‐benzoxazepin‐3‐one derivatives
Authors: Simon Lajos , Talpas S. Gizella , Fülöp Ferenc , Bernáth Gábor , Argay Gyula , Kálmán Alajos , Sohár PÁL
Published: March 2009

trans‐Perhydro‐1,4‐benzoxazepin‐3‐ones 2a‐c were synthesized and transformed to condensed‐skeleton perhydro‐trans‐1,4‐benzoxazepines 3a,b, the thiones 4a,b, the urea derivatives 5a,b, and N‐acylated compounds 6a‐e. Compounds 6b,d were ring‐opened by hydrochloric acid in ethanol to yield trans‐2‐(1‐carbethoxyethoxy)‐1‐acylaminomethylcyclohexane derivatives 7b,d. The 1H‐ and 13C‐nmr investigation and X‐ray analysis of 5b and 6c,d proved that the expected N‐acylated derivatives were formed and that both rings of the trans anellated compounds have a chair conformation.
Long‐range fluorine‐proton coupling in 1,2,4‐triazole derivatives
Authors: Kane John M. , Dalton Christopher R. , Staeger Michael A. , Huber Edward W.
Published: March 2009

Several 1,2,4‐triazole derivatives containing a 2‐fluorophenyl substituent at either the 3‐ or 5‐position and a methyl group at the 4‐position were synthesized. These derivatives exhibit long‐range 19F‐1H and 19F‐13C through‐space coupling in their 1H and 13C nmr spectra between the fluorine and the 4‐methyl group. The close spatial proximity of these nuclei was confirmed by X‐ray analysis and by fluorine irradiated proton observe ({19F}‐1H) NOE difference spectroscopy.
Bentonitic earth catalyzed rearrangement of aryl 1,1‐dimethylpropargyl ethers. Synthesis of 2,2‐dimethyl‐2H‐1‐benzopyrans
Authors: Cruz‐Almanza Raymundo , Pérez‐Flores Francisco , Breña Leonardo , Tapia Eva , Ojeda Reyna , Fuentes Aidee
Published: March 2009

Mexican Bentonitic earth (Tonsil) catalyzed the Claisen rearrangement of aryl 1,1‐dimethylpropargyl ethers under mild conditions to provide 2,2‐dimethyl‐2H‐1‐benzopyrans. The synthesis of encecalin 2f and desmethoxyencecalin 2i, two biologically active products among other natural products (2b, 2e) was performed by this procedure.
Photochemical behavior of 4‐(ω‐enyl)‐ and 4‐(ω‐dienyl)‐2‐pyrones
Authors: Shimo Tetsuro , Ueda Shinichi , Somekawa Kenichi
Published: March 2009

4‐(ω‐Enyl)‐2‐pyrone 3 and two types of 4‐(ω‐dienyl)‐2‐pyrones 4–6, 9 and 10 were prepared and the photochemical behavior was investigated. Photosensitized reaction of 3 afforded [2+2]‐cycloadduct 11 site‐specifically. On the other hand, 4 and 5 gave geometrical isomers, respectively. 2‐Pyrones 6, 9 and 10 possessing pendant furans gave no adduct. The reasons for the differences are described.
Synthesis of 3‐(dibromoacetyl)tropolone and its reactions with thioureas and thioamides
Authors: Maeda Yasunari , Imafuku Kimiaki
Published: March 2009

3‐(Dibromoacetyl)tropolone (3) was obtained in the reaction of 3‐acetyltropolone with two equimolar amounts of phenyltrimethylammonium tribromide. This tropolone 3 reacted with thiourea, 1‐methyl‐2‐thiourea, and 1‐phenyl‐2‐thiourea to afford N‐unsubstituted and N‐methyl‐ or N‐phenyl‐substituted 3‐(2‐amino‐4‐thiazolyl)tropolones. The reactions of 3 with thioacetamide and thiobenzamide gave 3‐(2‐methyl‐and 2‐phenyl‐4‐thiazolyl)tropolones.
Heterocyclic steroids: Synthesis of androsteno[17,16‐d]pyrazoles and androsteno[17,16‐e]pyrimidines
Authors: Siddiqui A. U. , Rao V. U. Maheshwar , Maimirani M. , Siddiqui A. H.
Published: March 2009

The Vilsmeier‐Haack reaction of 3β‐acetoxyandost‐5‐en‐17‐one (1) with phosporous oxychloride and dimethylformamide gave 3β‐acetoxy‐17‐chloro‐16‐formylandrosta‐5,16‐diene (2). Reaction of 2 with hydrazine and phenylhydrazine provided substituted 5‐androsteno[17,16‐d]pyrazoles 3 and 4 respectively. Similarly, condensation of 2 with urea and guanidine hydrochloride revealed the formation of the corresponding substituted pyrimidines 5 and 6 respectively.
Preparation of n‐butyl‐2‐(2′‐triphenylmethyltetrazol‐5‐yl)phenylborinic acid
Authors: Lo Young S. , Rossano Lucius T. , Meloni David J. , Moore James R. , Lee Ying‐Chi , Arnett John F.
Published: March 2009

Understanding the mechanism of formation of an impurity in the key step of the synthesis of Losartan (1) helped devise a procedure to synthesize the title compound in high yield.
On triazoles. XXXV. The reaction of 5‐amino‐1,2,4‐triazoles with di‐ and triketones
Authors: Reiter József , Pongó László , Kövesdi István , Pallagi István
Published: March 2009

The reaction of 5‐amino‐3‐Q‐1H‐1,2,4‐triazoles 1 with aliphatic, aromatic and cyclic 1,3‐diketones, 1,4‐diketones, and different linear and non linear triketones was studied. It was proved that in case of unsym‐metrical aliphatic 1,3‐diketones the regiochemical outcome of the reaction was influenced by steric factors. In case of triacetylmethane and 3‐(4‐chlorobenzyl)‐2,4‐pentanedione the splitting of one acetyl group from the reactant was observed during the reaction. A liner triketone, namely the 2,4,6‐trioxoheptane reacted as a simple 1,3‐diketone.
Synthesis of 5‐azido‐4‐cyanoimidazole and its reaction with active methylene compounds
Authors: Paula Freitas A. , Fernanda M. , Proença J. R. P. , Booth Brian L.
Published: March 2009

Diazotisation of 1‐acetamido‐5‐amino‐4‐cyanoimidazole 2 using sodium nitrite in aqueous acetic acid gave 5‐azido‐4‐cyanoimidazole 3 in 94% yield. Reaction of 3 with active methylene compounds R1COCH2R2 [R1 = Me, R2 = COMe; R1 = Me, R2 = COPh; R1 = Me, R2 = COOEt] or malononitrile in the presence of base led either to imidazo[5,1‐d][1,2,3,5]tetrazepines 6 and 8 or to imidazolyltriazoles 5, 7 and 9, depending on the reaction conditions. Tetrazepine 6c evolves to triazole 7c or 5c respectively in the presence of acid or by further treatment with base. Purine 10 was also isolated in the reaction of 3 with malononitrile.
Reactions of polyfunctional amines with 3‐amino‐4‐(anilinothio‐methylidene)‐2‐cyano‐2‐pentenedioic acid diethyl ester
Authors: Winnik Witold
Published: March 2009

3‐Amino‐4‐(anilinothiomethylidene)‐2‐cyano‐2‐pentenedioic acid diethyl ester reacts with ethylenedi‐amine, 1,3‐propylenediamine and 1,4‐butylenediamine affording bicyclic cyclocondensation products. The title compound reacts with diethylenetriamine and 2‐(2‐aminoethylamino)ethanol to give new seven membered ring tricyclic compounds. The mechanism for these reactions is discussed.
Cyclodehydration of N‐(2‐nitroaryl)‐1,2,3,4‐tetrahydroisoquinoline derivatives
Authors: Andrew Hedley K. , Stanforth Stephen P.
Published: March 2009

Compounds 1a‐1g gave the corresponding N‐oxide derivatives 3a‐3g when heated with acetic or propionic acid.
Synthesis of 1‐(benzotriazol‐1‐yl)alkyldiphenylphosphine oxides and their transformations to novel benzotriazol‐1‐yl‐substituted cyclopropanes
Authors: Katritzky Alan R. , Wu Hong , Xie Linghong , Jiang Jinlong
Published: March 2009

Diphenylphosphinous anion reacted with chloromethylbenzotriazole to give (benzotriazol‐1‐yl)methyldiphenylphosphine oxide, which, after lithiation, was alkylated to give 1‐(benzotriazol‐1‐yl)alkyldiphenylphosphine oxides in good yield. Treatment of 1‐(benzotriazol‐1‐yl)alkyldiphenylphosphine oxides with n‐butyllithium followed by condensation with epoxides, afforded benzotriazol‐1‐yl‐substituted cyclopropanes, which underwent further lithiation and subsequent reaction with numerous electrophiles to provide a variety of novel benzotriazol‐1‐yl‐substituted cyclopropane derivatives.