bluuebunny/crossref_metadata_2025_split huggingface dataset:
The synthesis of 7,8‐dihydroimidazo[1,2‐e]pyrazolo[1,5‐a]‐1,3,5‐triazines, 8,9‐dihydro‐7H‐pyrimido[1,2‐e]pyrazolo[1,5‐a]‐1,3,5‐triazines and 7,8,9,10‐tetrahydro[1,3]diazepino[1,2‐e]pyrazolo[1,5‐a]triazines
Authors: Lalezari I. , Sadeghi‐Milani S. 
Published: April 2009

AbstractCyclic hydrazino amidines were converted to the corresponding aminopyrazolyl derivatives. Ring closure between the amino groups of pyrazoline moieties and NH groups of cyclic amidines afforded the following ring systems: 7,8‐Dihydroimidazo[1,2‐e]pyrazolo[1,5‐a]‐1,3,5‐triazines, 8,9‐dihydro‐7H‐pyrimido[1,2‐e]pyrazolo[1,5‐a]‐1,3,5‐triazines and 7,8,9,10‐tetrahydro[1,3]diazepino[1,2‐e]pyrazolo[1,5‐a]‐1,3,5‐triazines.
Potential histidine decarboxylase inhibitors. II. 3‐(4‐Imidazolyl)‐2‐pyridine and piperidinecarboxylates
Authors: Degraw J. I. , Engstrom J. S. , Ellis M. , Johnson H. L. 
Published: April 2009

AbstractThe synthesis of methyl 3‐(4‐imidazolyl)‐2‐pyridine (12) and piperidineearboxylates (13) is described. Hydrolysates of these esters were found to be devoid of inhibitory activity against histidine decarboxylase. 3‐Bromoacetyl‐2‐pieoline (2) could be converted to 3‐(4‐imidazolyl)‐2‐picoline (6) by two different routes. Treatment of 6 with peroxide and acetic anhydride, followed by transesterification yielded the 2‐hydroxymcthyl pyridine (9). Oxidation of 9 followed by esterification gave the imidazole pyridine acid ester (12) which after hydrogenation afforded the imidazolylpiperidine ester (13).
The resolution of an optically active pyridinethiol
Authors: Mulvey Dennis M. , Jones Howard 
Published: April 2009

AbstractThe resolution of a chiral pyridine thiol has been eonveniently carried out through derivatives with optically active α‐phenethylisoeyanates. Optically active heterocyclic thiols in which the thiol occupies the center of chirality are not known in the literature. In conjunction with a synthetic program dealing with derivatives and analogues of 5‐mercaptopyridoxine (1), the preparation of such species was accomplished. Their resolution proved to be difficult, but the techniques devised herein should prove of general utility for other heteroeyclic thiols or alcohols.
Tetrahydropyridoazepines and tetrahydropyridoazepinones from the corresponding dihydroquinolones
Authors: Jössang‐Yanagida Akino , Gansser Charles 
Published: April 2009

AbstractThe p‐toluenesulfonate of 7,8‐dihydro‐5(6H)quinoloneoxime(3) was subjected of a Beckmann rearràngement. The resulting 2,3,4,5‐tetrahydro‐1H‐pyrido[3,2‐b]azepin‐2‐one (4) was reduced with lithium aluminum hydride affording 2,3,4,5‐tetrahydro‐1H‐pyrido[3,2‐b] azepine (5). 5,6‐l)ihydro‐8(7H)quinolone (7), obtained by oxidation of 5,6,7,8‐tetrahydro‐8‐quinolinol (6), was converted into the p‐toluenesulfonate of 5,6‐dihydro‐8(7H)quinolone oxitne (9). Similarly the latter compound could be rearranged into 2,3,4,5‐letrahydro‐1H‐pyrido [2,3‐b] azepin‐2‐one (10) which on reduction produced 2,3,4,5‐tetrahydro‐1H‐pyrido [2,3‐b] azepine (11).
Perhydroisoindoliniums et perhydroisoquinoliniums: Préparation et étude stéréochimique
Authors: Mayrargue Joëlle , D'Engenières Michel Duchon , Miocque Marcel 
Published: April 2009

AbstractLes éthynylcyclohexanols aminométhylés en position 2 se cyclisent en présence d'eau pour former des perhydroisoindoliniums; les propynylcyclohexanols homologues eonduisent à des perhydroisoquinoliniums.Les diastéréoisomères ont été isolés. Leur stéréochimie est étudiée par spectrographie (1H rmn et 13C rmn): elle met en évidence une stéréopréférence pouvant aller jusqu' à la sélectivité complète lors de la cyclisation des aminocyclohexanols acétyléniques à l'état de mélanges de diastéréoisomères (obtention exclusive d'hétérocycles à jonction trans).
Synthesis and stereochemical analysis of isomeric N‐substituted 5‐ and 6‐propanilido‐2‐azabicyclo[2.2.2]octanes
Authors: Law Say‐Jong , Lewis Daniel H. , Borne Ronald F. 
Published: April 2009

AbstractThe synthesis and stereochemical analysis of N‐methyl and N‐phenethyl‐substituted 5‐ and 6‐propanilido derivatives of 2‐azabicyclo[2.2.2]octane were investigated for potential evaluation as analgesics related to fentanyl. Stereochemical assignments for the eight isomers reported here were made on the basis of nmr studies employing europium chemical shift reagents and hydrogen bonding studies employing ir analysis of the anilino‐ and propanilido‐derivatives.
The insertion and extrusion of heterosulfur bridges. VI. Comparative desulfurizations of dibenzothiophene and biphenylthiols
Authors: Klemm L. H. , Karchesy Joseph J. 
Published: April 2009

AbstractProducts were determined from reaction of biphenyl‐2‐thiol (5) with methanol in a packed flow reactor at elevated temperatures and ca. atmospheric pressure. At 450–550° thermolysis of 5 gives small yields of dibenzothiophene (1) and biphenyl (2). With sulfided alumina, products vary with reaction temperature from 82% S‐methyl‐5 at 250° to only 1 plus 2 at 550°. At 450° with sulfided cobaltous oxide‐molybdic oxide‐aluminum oxide (CMA‐1), 5 and its isomers give mainly desulfurization to 2 (81%), plus C‐melhylalion to melhylbiphenyls and fluorene. With CMA‐1 at 450° the arrays of products from 1 and 5 are closely similar.
Addition reactions of heterocycles. VI. Reactions of 1,2‐dimethylpyrrole and 1‐methyl‐2‐carbomethoxypyrrole with nitrilimines
Authors: Ruccia Michele , Vivona Nicolò , Cusmano Giuseppe 
Published: April 2009

AbstractAddition reactions of 1,2‐dimethylpyrrole and 1‐methyl‐2‐carbomethoxypyrrole with C‐acetyl‐N‐phenylnitrilimine, have been investigated. 1,2‐Dimethylpyrrole gives three different types of adducts: i.e. bis‐cycloadducts (Vc) and (VIc), spirocycloadduct (IX), and non cyclic bis‐adduct (XII). On the other hand, 1‐methyl‐2‐carbomethoxypyrrole gives the bis‐cycloadduct (VIb) only. Compound XII arises probably through a double 1,3‐addition reaction, whereas the formation of cycloadducts Vc, VIc, and IX depends on the substituents present at C2 of the pyrrole ring and consequentially on the intermediary occurence of mono‐cycloadduct (IIIc), its methylenic tautomer VII, VIc, and XL The behaviour of the cycloadducts towards heating or acidic treatment showed a termal cleavage of the pyrazoline ring and acidic cleavage of the pyrrolidine ring.
A base induced fragmentation of tetramisole
Authors: Fibiger Richard F. , Banks Allen R. , Jones Ted , Haltiwanger R. Curtis , Watt David S. 
Published: April 2009

AbstractThe exposure of dl‐2,3,5,6‐tetrahydro‐6‐phenylimidazo[2,1‐6 Jthiazole (tetramisole) to lithium diisopropylamide in tetrahydrofuran ruptures the thiazole ring to give, following the introduction of primary or secondary alkyl halides, 1‐(2′‐alkylthio)ethyl‐4‐phenylimidazoles. Conclusive evidence for the thiazole ring opening was obtained by a single crystal x‐ray diffraction study of 1‐(2′‐p‐bromobenzylthio)ethyl‐4‐phenylimidazole.
Pyrazolo[3,4‐b]pyridines. I. Xanthine and isoguanine analogs derived from 1‐methylpyrazolo[3,4‐b]pyridine
Authors: Schneller S. W. , Moore D. R. 
Published: April 2009

AbstractThe synthesis of 4,6‐dihydroxy‐l‐methylpyrazolo[3,4‐b Jpyridine (2) and 4‐amino‐6‐hydroxy‐1‐methylpyrazolo[3,4‐b] pyridine (3) as analogs of xanthine and isoguanine has been accomplished from ethyl 5‐amino‐1‐methylpyrazole‐4‐carboxylate (4) and 5‐amino‐1‐methylpyrazole‐4‐carbo‐nitrile (6), respectively.
Steric controls in the preparation of 1‐benzyl‐1,4‐dihydro‐3‐(2H)isoquinolones and 1‐benzyl‐1,2,4,5‐tetrahydro(3H)‐2‐benzazepin‐3‐ones via Beckmann rearrangement
Authors: Jensen Bruce L. , Michaud Dennis P. 
Published: April 2009

AbstractThe effect of substituents in the 1‐position of 2‐indanones and 2‐tetralones on the course of Beckmann rearrangement reactions was studied. Nmr spectral anaylses of the intermediate oximes and final products demonstrated that steric controls were operative both before and during rearrangement. Use of the appropriate substituents and reaction conditions makes this reaction scheme attractive for preparation of the title compounds.
Chlorination of 1H‐pyrrolo[3,2‐c]pyridin‐4,6(5H,7H)dione (3,7‐dideazaxanthine) and its 5‐methyl derivative
Authors: Schneller S. W. , Hosmane R. S. 
Published: April 2009

AbstractThe chlorination of 1H‐pyrrolo[3,2‐c]pyridin‐4,6(5H, 7H)dione (3,7‐dideazaxanthine) (2) and 5‐methyl‐1H‐pyrrolo[3,2‐c] pyridin4,6(5H,7H)dione (1 ‐methyl‐3,7‐dideazaxanthine) (3) with phenylphosphonic dichloride has yielded 4,6‐dichloro‐1H‐pyrrolo[3,2‐c]pyridine (2,6‐dichloro‐3,7‐dideazapurine) (1). A mechanism for the demethylation of the 5‐methyl derivative under these conditions is proposed. Ammonolysis of 4,6‐dichloro‐1H‐pyrrolo[3,2‐c] pyridine was unsuccessful while catalytic reduction of this dichloro derivative produced 1H‐pyrrolo[3,2‐c]‐pyridine (4).
Alkylation of picolinaldehyde with bromohydrins. A new class of heterocyclic ring tautomers
Authors: Dewhurst John Elton , Jones Paul R. 
Published: April 2009

AbstractEntry into the pyrido[2, 1‐c] [1,4]oxazinium and pyrido(2,1‐c] [1,4]oxazepinium ring systems has been achieved by the interaction of picolinaldehyde with 2‐bromoethanol and 3‐bromo‐propanol, respectively. The products, ring‐tautomeric hemiacetals, are presumably formed by rapid hemiacetalization, followed by an intramolecular Menschutkin Reaction.
About the mechanism of formation of 3‐azidoindazole from 3‐diazoindazole or 3‐indazolyldiazo phenyl sulphide and potassium azide
Authors: Slanovnik B. , Tišler M. , Polanc S. , Janežič D. 
Published: April 2009

AbstractIt has been shown by mass spectrometrie analysis that 3‐azidoindazole, the product of the reaction between 3‐diazoindazole and azide ion, was formed through acyclic pentazene(IV and V) and cyclic pentazole (VIII and IX) intermediates in the ratio 2:1.
Studies on the syntheses of analgesics. Part 50. Synthesis of optically active 2‐[4‐(1‐oxo‐2‐isoindolinyl)phenyl]propanoic acid. [Studies on the syntheses of heterocyclic compounds. Part 742]
Authors: Kametani Tetsuji , Kigasawa Kazuo , Hiiragi Mineharu , Ishimaru Haruhide , Haga Seiji , Shirayama Keiko 
Published: April 2009

Abstract2‐[4‐(1‐Oxo‐2‐isoindolinyl)phenyl]propanoic acid (1) having a potent analgesic and anti‐inflammatory activity could be obtained by three methods, which were found to provide extremely useful ways for the synthesis of 1 from the industrial point of view. (E)‐ and (Z)‐Isomers of 2‐butenoic acid and oxiranecarboxylic acid derivatives as the intermedaites in the synthesis of 1 were separated and characterized. Furthermore, the optical resolution of (±)‐2‐[4‐(1‐oxo‐2‐isoindolinyl)phenyl]propanoic acid was successfully achieved using cinchonidine as a resolution reagent.
Thiazoles and thiadiazines. The condensation of ethyl 4‐chloroacetoacetate with thiosemicarbazide
Authors: Campaigne E. , Selby T. P. 
Published: April 2009

AbstractBy varying the acidity, solvent polarity, and temperature when thiosemicarbazide reacted with ethyl 4‐chloroacetoacetate, ethyl 2‐amino‐6H‐1,3,4‐thiadiazine‐5‐acetate hydrochloride, ethyl 2‐hydrazinothiazole‐4‐acetate, and ethyl 2‐imino‐3‐aminothiazoline‐4‐acetate hydrochloride were prepared selectively. Double bond migration occurred after neutralizing the thiadiazine and thiazoline hydrochlorides to form the α,β‐unsaturated esters: 2‐amino‐5‐carbethoxymethylidene‐4,5‐dihydro‐6H‐1,3,4‐thiadiazine and 2‐imino‐3‐amino‐4‐carbethoxymethylidenethiazolidine. Pmr studies revealed that an equilibrium existed in solution between the imine and enamine tautomers of the thiadiazine free base. In the enamine structure, a 6‐membered hydrogen bonded ring system promotes stability. The thiadiazine contracted in acidic aqueous acetone to ethyl 2‐isopropylidenehydrazonothiazole‐4‐acetate.Monobenzoylation at the primary amine of the thiadiazine yielded ethyl 2‐benzamido‐6H‐1,3,4‐thiadiazine‐5‐acetate without disruption of the hydrogen bonded ring, but benzoylating the imino functionality of the thiazolidine caused deconjugation of the α,β‐unsaturated ester by double bond migration back into the ring, and ethyl 2‐benzimido‐3‐aminothiazoline‐4‐acetate was produced, dehydration yielded ethyl 2‐phenylthiazolo[3,2‐b]‐s‐triazole‐5‐acetate. This compound was also obtained by reacting 3‐phenyl‐1,2,4‐triazole‐5‐thiol with ethyl 4‐chloroacetoacetate, while the monobenzoylated derivative of the hydrazinothiazole, ethyl 2‐(2‐benzoylhydrazino)thiazole‐4‐acetate underwent a dehydrative cyclization to ethyl 3‐phenyl‐thiazolo [2,3‐c]‐s‐triazole‐5‐acetate.In chloroform solvent, the second site of benzoylation on the thiadiazine was ring nitrogen 3 while in ethanol or acetonitrile‐pyridine ring nitrogen 4 was benzoylated instead. Benzoylation at ring nitrogen 3 resulted in deconjugation of the α,β‐unsaturated ester moiety and formed the endocyclic imine, ethyl 2‐benzimido‐3‐benzoyl‐2,3‐dihydro‐6H‐1,3,4‐thiadiazine‐5‐acetate. However, deconjugation of the unsaturated ester did not occur after benzoylation at ring nitrogen 4; the product was trans‐2‐benzamido‐4‐benzoyl‐5‐carbethoxymethylidene‐4,5‐dihydro‐6H‐1,3,4‐thiadiazine.The hydrogen bonded oximes, syn‐2‐amino‐5‐ethyloxalyl‐6H‐1,3,4‐thiadiazine oxime, 3,3‐dimethyl‐5‐ethyloxalyl‐2H‐1,2,4‐triazolo[3,4‐b]thiazole oxime, and 2‐(2‐benzoylhydrazino)‐4‐ethyloxalylthiazole oxime were synthesized by nitrosation.2‐Amino‐5‐ethyloxalyl‐6H‐1,3,4‐thiadiazine oxime benzoate, 2‐benzamido‐5‐ethyloxalyl‐6H‐1,3,4‐thiadiazine oxime dibenzoate, and the tribenzoylated derivatives, 2‐benzimido‐3‐benzoyl‐5‐ethyloxalyl‐2,3‐dihydro‐6H‐1,3,4‐thiadiazine oxime benzoate and 2‐benzamido‐4‐benzoyl‐5‐ethyl‐oxalyl‐4H‐1,3,4‐thiadiazine oxime benzoate, of the thiadiazine oxime werè prepared. The oxime benzoylated first, the primary amine second, and the number 3 and 4 ring nitrogens last.
Some derivatives of 4H‐pyrano[4,3‐d]thiazole, a novel ring system
Authors: Philipp Adolf H. , Humber Leslie G. , Martel René R. 
Published: April 2009

AbstractA synthesis of the novel 4H‐pyrano[4,3‐d]thiazole ring system is described. Derivatives bearing alkylamine and alkanoic acid side chains have been prepared and tested for potential antidepressant and antiinflammatory activities, respectively; only marginal activities were found in these tests.
The insertion and extrusion of heterosulfur bridges. VII. Desulfurization of phenanthro[4,5‐bcd]thiophene by means of methanol and a molybdena catalyst
Authors: Klemm L. H. , Karchesy Joseph J. , Lawrence Ross F. 
Published: April 2009

AbstractPhenanthro[4,5‐bcd]thiophene (1) is converted into phenanthrene (2) (50%) and a mixture of methylphenanthrenes (3) (12%) by means of methanol and a sulfided cobaltous oxide‐molybdic oxide‐aluminum oxide catalyst (CMA‐1) at 450° in a flow system. Similarly, 2 gives 3; and 4‐methylphenanthrene yields 2 plus 3 (main component 3‐methylphenanthrene) under the same reaction conditions. Mechanisms of the reactions are discussed. A facile chromatographic separation for 1‐ and 4‐keto‐1,2,3,4‐tetrahydrophenanthrenes is presented.
The mass spectra of four‐membered alicyclic sulfur compounds
Authors: Scala A. A. , Colon Ismael 
Published: April 2009

AbstractThe mass spectra of thietane, trimethylene sulfoxide, and trimethylene sulfone are reported. The major competing reactions are four‐center fragmentation, heteroatom group elimination and rearrangement. The oxidation state of the sulfur atom has a profound effect upon the competition among these reaction channels. As the oxidation state of the sulfur increases the molecular ion becomes increasingly less stable and consequently the amount of rearrangement decreases. Elimination of the heteroatom increases as its oxidation state increases, while the amount of four‐center fragmentation decreases.
Linearly fused isoquinolines. Part II. The synthesis of the s‐triazolo[4,3‐b]isoquinoline system
Authors: Hajós Gy. , Messmer A. 
Published: April 2009

Abstract3‐Hydrazinoisoquinoline (2) was synthesized via its N‐oxide derivative by removal of the N‐oxide funçtion with titanium trichloride. Acylation of the hydrazino compound (2) led to suitable starting materials (4 and 6) for cyclization to the novel, linearly fused ring system: tri‐azolo[4,3‐b]isoquinoline, which was more stable in the form of its perchlorate salt. The structure of the first representatives of the new ring system was proved by ir, nmr and ms spectroscopy.
Synthesis of 3‐formylbenzo[b]furan and 1‐methyl‐3,4‐dihydrobenzo[b]‐furo[2,3‐c]pyridine
Authors: Shafiee A. , Mohamadpour M. 
Published: April 2009

AbstractStarting from the readily available 3‐methylcoumarilate, 3‐formylbenzo[b]furan was synthesized in high yield. The latter could be converted to 1‐methyl‐3,4‐dihydrobenzo[b]furo‐[2,3‐c]pyridine in moderate yield.
New routes to 1‐deoxy‐(3,4‐dihydro‐7,8‐dimethyl‐2,4‐dioxopyrimido[4,5‐b]‐quinolin‐10(2H)yl)‐D‐ribitols (5‐deazariboflavins)
Authors: Ashton Wallace T. , Brown Ronald D. , Tolman Richard L. 
Published: April 2009

AbstractThe acid‐catalyzed reaction of 6‐(N‐D‐ribityl‐3,4‐xylidino)uracil (1) with trimethyl ortho‐formate yields a bis(methoxymethylene) derivative (2), which is readily deprotected to give 5‐deazariboflavin (3). Correspondingly, 5‐methyl‐5‐deazariboflavin (6) is produced by cyclization of the tetraacetate of 1 with acetyl chloride in the presence of stannic chloride followed by deacetylation.
On the oxidation of N‐methylpyrimidinium salts
Authors: van der Plus H. C. , Buurman D. J. 
Published: April 2009

AbstractOxidation of 1,2‐dihydro‐1,3‐dimethyl‐2‐oxopyrimidinium bisulfate (1+·HSO) with hydrogen peroxide in acetic acid in the presence of potassium iodide gave 1,3‐dimethyl‐5‐iodouracil (65‐70%), 1,3‐dimethyluracil (10‐15%) and 3‐methyl‐2,4‐oxazolidinedione (10‐15%). Similar results were obtained on oxidation of the iodide (1+·I−). Oxidation of 1‐methyl‐4‐phenylpyrimidinium iodide or oxidation of 1‐methyl‐4‐phenylpyrimidinium methylsulfate in the presence of potassium iodide gave 1,6‐dihydro‐5‐iodo‐1‐methyl‐6‐oxo‐4‐phenylpyrimidine.
bis‐Isatoic anhydrides I. The preparation of bis‐isatoic anhydrides
Authors: Hall Randall W. , Bernhardt F. Christian , Beam Charles F. 
Published: April 2009

Abstractbis‐Isatoic anhydrides have been prepared in 20‐40% yield by the treatment of sodio‐isatoic anhydride with alkane dibromides and ditosylates.
Selenium heterocycles XXIII. Synthesis of 4,5‐dihydrophenanthro[1,3‐d]‐1,2,3‐selenadiazoles and 10,11 ‐dihydrophenanthro[1,2‐d]‐1,2,3‐selenadiazoles
Authors: Lalezari I. , Sadeghi‐Milani S. 
Published: April 2009

AbstractThe selenium dioxide oxidation of a series of 1,2,3,4‐tetrahydrophenanthrone and 1,2,3,4‐tetrahydrophenanthren‐4‐one semicarbazones afforded 4,5‐dihydrophenanthro[4,3‐d]‐1,2,3‐selenadiazoles and 10,11‐dihydrophenanthro[1,2‐d]‐1,2,3‐selenadiazoles. The latter series which represent a new type of selenaazasteroidal compounds were pyrolyzed and gave the corresponding 1,4‐deselenine derivatives.
N,N‐Disubstituted 4‐amino‐3‐chloro‐5,6‐polymethylene‐2H‐pyran‐2‐ones
Authors: Evangelisti Filippo , Bignardi Gaetano , Bargagna Alberto , Schenone Pietro 
Published: April 2009

AbstractThe title compounds were obtained by dehydrochlorination with collidine, DBN or triethyl‐amine of N,N‐disubstituted 4‐amino‐3,3‐dichloro‐3,4‐dihydro‐5,6‐polymethylene‐2H‐pyran‐2‐ones already described.
A facile synthesis of 2‐phenylbenzo[b]thiophene‐3‐amine and the corresponding S‐oxides
Authors: Beck James R. 
Published: April 2009

AbstractA rapid synthesis of 2‐phenylbenzo[b]thiophene‐3‐amine and its S‐oxides from o‐nitrobenzonitrile is described. Also reported is the preparation of 2‐phenylbenzo[b]thiophene‐3‐(2H)one, 1,1‐dioxide from methyl o‐nitrobenzoate.
Reaction of thiete 1,1‐dioxide with α‐chlorobenzalphenylhydrazine and methyl phenylhydrazonochloroacetate
Authors: Croce Piero Dalla , Del Buttero Paola , Mayorana Stefano , Vistocco Raffaele 
Published: April 2009

AbstractThiete 1,1‐dioxide reacts with 2 moles of α‐chlorobenzalphenylhydrazine and methyl phenylhydrazonochloroacetate in the presence of triethylamine leading to the pyrazole derivatives 6 and 7 whose structure and mechanism of formation are discussed.
New synthesis of condensed heterocycles from isoxazole derivatives VI. 2,5‐Dimethyl‐3‐aeetyl‐7‐amino‐1H‐pyrrolo[3,2‐b] pyridine
Authors: Aiello E. , Dattolo G. , Cirrincione G. , Plescia S. , Daidone G. 
Published: April 2009

AbstractA new synthesis of pyrrolo[3,2‐b] pyridine starting with pyrrole ring is described. The procedure allows the synthesis of 4‐azaindoles bearing a sensitive group at C‐7. The nitration of 4b with nitric acid and acetic anhydride at −15° gave 5. The hydrogenation of 5 led to simultaneous reduction of N‐hydroxy and nitro groups and to hydrogenolysis of the isoxazole nucleus, affording an appropriate chain of atoms to building up the pyrrolo[3,2‐b] pyridine ring.
Mechanism study of base‐catalyzed cyclization of 2‐nitrophenylhydrazine in aqueous solution
Authors: Munson James W. , Hodgkins Thomas G. 
Published: April 2009

AbstractThe mechanism of cyelizalion of 2‐nitrophenylhydrazine to 1‐hydroxybenztriazole in alkaline aqueous solutions is studied. Kinetic parameters, product distribution and activation parameters are determined. A mechanism involving direct attack of the β‐hydrazino nitrogen on the nitrogen ol the nilro group with elimination of water is postulated. Substituted 2‐nitrophenylhydrazines are synthesized and studied under the same conditions.
Synthesis of 1,3‐dihydro‐2H‐benzimidazol‐2‐one from 2‐aminobenzamide
Authors: Heyman Duane A. 
Published: April 2009

AbstractA method for the synthesis of 2‐henzimidazolone (1) has been devised which does not depend on 1,2‐diaminobenzene (2) as a starting material. This method produces 1 in good yield by the reaction of hypohalite with 2′‐carbamoylphthalanilic acid (7), a compound readily prepared by the reaction of 2‐aminobenzamide (3) and phthalic anhydride. Contrary to prior indications 1 can be hydrolyzed in the presence of acid at temperatures greater than 200 giving excellent yields of 2.
Synthèse de systèmes comportant deux cycles thiophéniques orthocondensés à un hétérocycle à sept chainons
Authors: Meunier P. 
Published: April 2009

AbstractLa réduction du carbonyle de dérivés des bithiényles porteurs sur chacun des cycles thiophéniques, d'un groupe formyle lié à l'atome de carbone voisin de la jonction intercyclique, conduit aux dialcools primaires attendus. Ces dialcools peuvent donner naissance aux bithiényles bis‐halogénomethylés correspondants. Par deshydratation des alcools et par action du sulfure de sodium ou d'amines sur les halogénures obtenus, on accéde respectivement à des dihydrodithieno[c,e]oxépinnes, thiépinnes et azépines. Lesdérivés tétraméthylés des “oxépinnes” précédentes ont été obtenus à partir de bithiényles diacé'tylés.
Synthesis of α‐hydroxy‐β‐lactams
Authors: Marthas M. S. , Amin S. G. , Chawk H. P. S. , Bose Ajay K. 
Published: April 2009

AbstractA convenient synthesis of α‐hydroxy‐β‐lactams has been devised that involves the annelation of an inline with benzyloxyacetyl chloride and triethylamine and subsequent hydrogenolysis in the presence of palladium on carbon. In most cases a cis‐β‐lactam was obtained. A thioimidate can also be used as the imino component in the annelation reaction but the hydrogenolysis step fails. The annelation of the appropriate thiazoline to a 6‐epi‐penicillin derivative occurred much more readily with benzyloxyacetyl chloride than with azidoacetyl chloride.
New polycyclic pyran ring systems
Authors: Mazzei Mauro , Roma Giorgio , Ermili Aldo 
Published: April 2009

AbstractReaction of 1‐oxo‐3‐dialkylamino‐1H‐naphtho[2,1‐b]pyrans, 4‐hydroxycoumarin and formaldehyde gave rise to the formation of 1‐oxo‐2‐((2‐oxo‐4′‐hydroxy‐2′H‐1′‐benzopyran‐3′‐yl)‐melhyl J‐3‐dialkylamino‐1H‐naphtho[2,1‐b]pyrans. When these compounds were refluxed in glacial acetic acid, cyclization occurred and 6,8‐dioxo‐6H,7H,07‐,5,15,16‐trioxadibenzo[a,j]‐naphthacene arose by cleavage of the dialkylamino group. In a similar manner, starting from suitable products, many other trioxanaphthacene or azadioxanaphthacene derivatives were synthesized.