bluuebunny/crossref_metadata_2025_split huggingface dataset:
Products from Furans. XVI. Novel synthetic routes to sympathomimetic amine analogues via 6‐hydroxy‐2H‐pyran‐3(6H)‐ones
Authors: Georgiadis Minas P. , Haroutounian Serkos A. , Couladouros Elias A. , Apostolopoulos Costas D. , Chondros Kostas P. 
Published: March 2009

AbstractNovel heterocyclic analogues mimicking compounds with antipsychotic activity (sympathomimetic amines) were synthesized. These compounds contain the phenyl‐substituted pyran ring system as a consequence of their common route of preparation. Furthermore an example of the synthetic route for preparing compounds having the features of both β‐hydroxy‐β‐phenylethylamine and GABA is also presented.
Synthesis and reactions of 3‐carboxytropolone. Conversion to heterocycle‐fused troponoid compounds
Authors: Zhang Luo‐Cheng , Imafuku Kimiaki 
Published: March 2009

AbstractThe haloform reaction of 3‐acetyltropolone (1) afforded 3‐carboxytropolone (2) which was treated with diazomethane to give 2‐methoxy‐3‐methoxycarbonyltropone (3a) and 2‐methoxy‐7‐methoxycarbonyltropone (3b). The tropolone 2 reacted with hydrazine to afford 2‐hydrazino‐3‐hydrazinocarbonyltropone (10) or 2‐hydrazinotropone (11), depending on the reaction time. The reaction of 2 with phenylhydrazine produced 3‐hydroxy‐1‐phenyl‐1,8‐dihydrocycloheptapyrazol‐8‐one (14). The treatment of 2‐methoxy‐3‐methoxycarbonyltropone (3a) with hydrazine or phenylhydrazine gave cyclization products 12 and 15, respectively. The reaction of 2‐methoxy‐7‐methoxycarbonyltropone (3b) with hydrazine, phenylhydrazine, or methylhydrazine gave 2‐hydrazino‐ (13), 2‐(2‐phenylhydrazino)‐ (16), and 2‐(2‐methylhydrazino)‐7‐methoxycarbonyltropone (17), respectively.
Two‐dimensional NMR studies of 2‐substituted thioxanthene sulfoxides
Authors: Mlotkowska B. L. , Cushman James A. , Harwood J. , Lam W. W. , Ternay A. L. 
Published: March 2009

Abstract2‐Fluoro‐, 2‐chloro‐, 2‐bromo‐, 2‐methyl‐, and 2‐methoxythioxanthene have been prepared by borane reduction of the corresponding thioxanthone. The corresponding sulfoxides were prepared by m‐chloroperoxybenzoic acid oxidation of these sulfides. Proton and carbon chemical shifts have been assigned to these thioxanthene sulfoxides with the aid of LROCSCM and SROCSCM experiments. Carbon chemical shifts in the unsubstituted rings occur at approximately 125 ppm (C5); 128 ppm (C6); 130 ppm (C7); 128 ppm (C8); and 36 ppm (C9). The methylene protons appears as AB doublets at approximately 4.2 and 3.8 ppm. All sulfoxides have the same, pseudo‐equatorial geometry.
Proton‐ionizable crown compounds. 20. The synthesis of polyazatriazolo‐, polyazabistriazolo‐ and bispyridono‐crown ligands containing lipophilic hydrocarbon substituents
Authors: Bradshaw Jerald S. , Krakowiak Krzysztof E. , Huszthy Peter , Izatt R. M. 
Published: March 2009

AbstractFour new macrocyclic polyaza‐crown compounds containing a triazole subcyclic group and two to five lipophilic hydrocarbon substituents have been prepared from the appropriate polyamine and N‐THP‐protected 2,5‐triazoledimethyl dichloride. N,N,N',N'‐Tetrabenzyltetraazabistriazolo‐18‐crown‐6 was prepared from N,N'‐dibenzylethylenediamine and N‐THP‐protected 2,5‐triazoledimethyl dichloride. Biscyclohexano‐bispyridono‐18‐crown‐6 was prepared from trans‐ 1,2‐cyclohexanediol and THP‐protected 4‐hydroxy‐2,6‐pyridinedimethyl ditosylate.
Study on the murexide reaction. V
Authors: Koyama Matajiro , Kozuka Hiroshi , Takada Atsushi 
Published: March 2009

AbstractAlthough the reaction of caffeine with hydrogen peroxide/hydrochloric acid or nitric acid and then with ammonia has been known to give a purple coloration (Murexide reaction), the use of hydrazine instead of ammonia is found to provide no purple coloration. The reaction of caffeine with hydrogen peroxide/hydrochloric acid and then with hydrazine hydrate afforded a yellow reaction mixture, from which 4‐methyl‐6‐(N‐methylcarbamoyl)‐3,5‐dioxo‐2,3,4,5‐tetrahydrotriazine 9, oxalyl hydrazide 10 and hydroxylamine hydrochloride were isolated. The reaction of caffeine with nitric acid and then with hydrazine hydrate furnished a yellow reaction mixture, from which 8‐amino‐1,3,7‐trimethyl‐2,6‐dioxo‐1H,3H,7H‐xanthine 11, 9 and hydroxylamine nitrate were isolated. Compound 9 was clarified to be produced from 3‐hydroxy‐4,6‐dimethyloxazolo[4,5‐d]pyrimidine‐2,5,7(3H,4H,6H)‐trione 3 and 1,3‐dimethylalloxan 7 by the ring transformation with hydrazine.
Synthesis of 2‐Aryl‐3‐hydroxy‐4,9‐dihydrocyclohepta[b]pyran‐4,9‐diones
Authors: Jin Young‐Zhi , Jin Zhong‐Tian , Imafuku Kimiaki 
Published: March 2009

Abstract3‐(2‐Bromoacetyl)tropolone (1) reacted with benzaldehydes 2a‐g in the pressence of alkali at low temperature to give 2‐aryl‐3‐hydroxy‐4,9‐dihydrocyclohepta[b]pyran‐4,9‐diones 3a‐g in good yields.
(±)‐5′‐Nor ribofuranoside carbocyclic guanosine
Authors: Patil Sharadbala D. , Schneller Stewart W. 
Published: March 2009

AbstractThe synthesis of the guanine derivative (±)‐2‐amino‐1,9‐dihydro‐9‐[(1′α,2′β,3′β,4′α)‐(2′,3′,4′‐trihydroxy‐1′‐cyclopentyl]‐6H‐purin‐6‐one (2) is described. This compound is viewed as the carbocyclic ribofuranoside guanine nucleoside analogue lacking the 5′‐methylene.
The parent of 2‐(4,5‐dihydro‐1H‐tetrazol‐5‐ylidene)‐2‐cyanoacetate: Synthesis and reactivity X‐ray structure of (E)2‐[1‐(2,2‐dimethylpropyl)‐4,5‐dihydro‐1H‐tetrazol‐5‐ylidene]‐2‐cyanoacetate
Authors: Saalfrank Rolf W. , Lurz Claus‐Jürgen , Wirth Uwe , Von Schnering Hans Georg , Peters Karl 
Published: March 2009

AbstractReaction of 3,3‐diazido‐2‐cyanoacrylate 5 with four moles of ammonia gives tetrazolyl‐bisammonium salt 7. The key‐intermediate is the amino‐vinyl azide 6 which spontaneously undergoes a 1,5′ ring‐closure reaction followed by double deprotonation. Treatment of 7 with hydrochloric acid yields the parent of 2‐(4,5‐dihydro‐1H‐tetrazol‐5‐ylidene)‐2‐cyanoacetate 9 (R = Me, Et) as the only tautomer. Regiospecific monoalkylation of bisammonium salt 7a with dimethyl sulfate and reaction of ammonium salt 12 with hydrochloric acid gives (E)2‐(1‐methyl‐4,5‐dihydro‐1H‐tetrazol‐5‐ylidene)‐2‐cyanoacetate (13) (X‐ray structure of derivative 14). Compound 13 can also be obtained from vinyl azide 10 and methylamine. This experiment as well as AM1 calculations of 9a, 23 and 24 strongly favour tautomer 9a.
Synthesis of 1,8‐, 1,6‐ and 3,6‐dichloro‐9H‐thioxanthen‐9‐ones
Authors: Okabayashi Ichizo , Fujiwara Hidetoshi , Tanaka Chika 
Published: March 2009

AbstractCyclization of 2‐chloro‐6‐[(3‐chlorophenyl)thio]benzoic acid (2) gave a mixture of 1,8‐, 3, and 1,6‐dichloro‐9H‐thioxanthen‐9‐ones 4. The mixture was converted to 1,8‐diamino‐ 7, and 1‐amino‐6‐chloro‐9H‐thioxanthen‐9‐ones 8, from which 3 and 4 were prepared separately, respectively. From a mixture of 4 and 3,6‐dichloro‐9H‐thioxanthen‐9‐one (11) obtained by cyclizing 4‐chloro‐2‐[(3‐chlorophenyl)thio]benzoic acid (10) was separated 11 by conversion of 4 to 8.
An improved synthesis of 3,6‐diamino‐1,2,4,5‐tetrazine. II. From triaminoguanidine and 2,4‐pentanedione
Authors: Coburn M. D. , Buntain G. A. , Harris B. W. , Hiskey M. A. , Lee K.‐Y. , Ott D. G. 
Published: March 2009

AbstractA new synthesis for the title compound that gives an 80% overall yield was developed. Treatment of triaminoguanidine monohydrochloride (1) with 2,4‐pentanedione (2) gave 3,6‐bis(3,5‐dimethylpyrazol‐1‐yl)‐1,2‐dihydro‐1,2,4,5‐tetrazine (3) in 80–85% yield. Oxidation of 3 with nitric oxide or nitrogen dioxide to 3,6‐bis(3,5‐dimethyylpyrazol‐1‐yl)‐1,2,4,5‐tetrazine (4) followed by ammonolysis of 4 gave 3,6‐diamino‐1,2,4,5‐tetrazine (5) in guantitatively yields.
Preferred conformations of some 2‐pyridyl substituted thiourea derivatives. A reinvestigation of NMR spectral data
Authors: Kascheres Albert , Ueno Missao 
Published: March 2009

AbstractA previous report involving 1H nmr spectra of some 1‐phenyl and 1‐benzoyl 3‐(2‐pyridyl)thioureas was reinvestigated and found to be incorrect. Analysis of the data permits the designation of preferred conformations for these systems.
Reaction of tris(alkylthio)cyclopropenyl cations with 2‐pyridylmagnesium bromide as a new route to indolizines
Authors: Kojima Hideo , Kinoshita Yasuo , Matsumura Noboru , Inoue Hiroo 
Published: March 2009

AbstractThe reaction of tris(isopropylthio)‐ and tris(tert‐butylthio)cyclopropenylium perchlorates 1a and 1b with 2‐pyridylmagnesium bromide in dry tetrahydrofuran at room temperature gave 1,2,3‐tris(isopropylthio)‐ and 1,2,3‐tris(tert‐butylthio)indolizines 2a and 2b, respectively, in high yields.
Total assignment of the proton and carbon NMR spectra of the alkaloid quindoline — utilization of HMQC‐TOCSY to indirectly establish protonated carbon‐protonated carbon connectivities
Authors: Spitzer Timothy D. , Crouch Ronald C. , Martin Gary E. , Sharaf Maged H. M. , Schiff Paul L. , Tackie Albert N. , Boye Gilbert L. 
Published: March 2009

AbstractThe reisolation of the indoloquinoline alkaloid quindoline (also known as norcryptolepine) from Cryptolepis sanguinolenta is reported. The structure was unequivocally confirmed by two‐dimensional nmr methods; the proton and carbon spectra were assigned for the first time. Because of congestion in the proton spectrum HMQC‐TOCSY was used as an alternative to the more familiar COSY experiment. In addition to establishing proton‐proton connectivities, HMQC‐TOCSY affords the added benefit of providing, in an indirect sense, connectivity information between protonated carbons.
Studies on pyrazines. 24. A simple and versatile synthetic method for 3‐alkoxy‐ and 3‐aminopyrazinecarbonitriles
Authors: Sato Nobuhiro , Matsui Nobuo 
Published: March 2009

AbstractNew and concise synthetic methods of 3‐alkoxy‐ and 3‐aminopyrazinecarbonitriles by nucleophilic displacement of 3‐phenylsulfonylpyrazinecarbonitriles are reported.
Studies on phenothiazines. Part 16. Synthesis and spectral studies of substituted 1,2‐dichlorophenothiazines
Authors: Gupta R. R. , Saraswat Vandana , Gupta Archana , Jain Mukesh , Gupta Vandana 
Published: March 2009

AbstractSynthesis of the title compounds by the Smiles rearrangement has been reported. 1,2‐Dichloro‐7‐substituted phenothiazines have been prepared by the Smiles rearrangement of 3,4‐dichloro‐2‐formamido‐2′‐nitro‐4′‐substituted‐diphenyl sulphides. The latter were obtained by the formylation of the diphenyl sulphides obtained by the condensation of 2‐amino‐3,4‐dichlorobenzenethiol with o‐halogenonitrobenzenes. 9‐Nitrophenothiazines have been prepared by the reaction of 2‐amino‐3,4‐dichlorobenzenethiol with substituted o‐halonitrobenzenes containing a nitro group at both ortho positions to the halo atom in which Smiles rearrangement occurs in situ. The ir, nmr and mass spectral studies are also included.
Synthesis of 2,3,4,5‐tetranitropyrrole
Authors: Hinshaw Jerald C. , Edwards W. Wayne , George Clifford , Gilardi Richard 
Published: March 2009

AbstractDealkylation of 1‐tert‐butyl‐2,3,4‐trinitropyrrole in boiling trifluroacetic acid gave 2,3,4‐trinitropyrrole, the structure of which was confirmed by X‐ray crystallography. Treatment of this trinitropyrrole with nitric acid/oleum briefly at 60° gave 2,3,4,5‐tetranitropyrrole.
Reduction of substituted 1H‐4,5‐dihydroimidazolium salts
Authors: Salerno Alejandra , Ceriani Vanina , Perillo Isabel A. 
Published: March 2009

AbstractReactions of several substituted 1H‐4,5‐dihydroimidazolium salts 1 with nucleophilic and electrophilic reducing agents acting via hydride transfer were explored. Reaction of compounds 1 with lithium aluminum hydride in THF afforded the corresponding imidazolidines 2. When alkaline borohydrides (sodium borohydride, potassium borohydride, sodium cyanoborohydride) in ethanol at room temperature were used, partial or total over‐reduction of compounds 2 leading to N,N,N'‐trisubstituted ethylenediamines took place on occasion. Results may be explained taking into account that reductive cleavage of 2 proceeds via a stabilized iminium ion present in protic solvents. Treatment of compounds 1 with an excess of borane in THF afforded the corresponding imidazolidines 2 or their borane complexes, according to the substituent type.
Synthesis of large‐ring lactams by a carbene‐anion bond forming reaction
Authors: Williams Eric L. 
Published: March 2009

AbstractTreatment of large‐ring lactams 1 with potassium t‐butoxide results in the formation of bicyclic structures 2. Evidence was obtained to support the formation of 2 through a carbene‐anion coupling. The structures of a series of bicyclic lactams 2 have been rigorously defined.
Synthesis of substituted 1,4‐diazepino[5,6,7‐kl]acridines and imidazo[4,5,1‐de][1,4]diazepino[5,6,7‐mn]acridines
Authors: Cholody Wieslaw M. , Konopa Jerzy , Martelli Sante 
Published: March 2009

AbstractThe synthesis of some substituted ll‐methoxy‐7‐nitro‐4H,8H‐2,3‐dihydro‐1,4‐diazepino[5,6,7‐kl]acridines 4 with more diversified chains at position 4 is described. A convenient method for transformation of these compounds into the corresponding 4‐substituted 12‐methoxy‐4H‐2,3‐dihydroimidazo[4,5,1‐de][1,4]diazepino‐[5,6,7‐mn]acridine (5) is reported.
Thermolysis of pentasubstituted 3‐hydroxy‐1,2‐dioxolanes
Authors: Baumstark A. L. , Vasquez Pedro C. 
Published: March 2009

AbstractA series of pentasubstituted 3‐hydroxy‐1,2‐dioxolanes, la‐e, was synthesized by oxygen trapping of β‐keto radicals formed during α‐azo hydroperoxide decomposition. Thermolysis of the pentasubstituted 3‐hydroxy‐1,2‐dioxolanes (hemiperketals) in benzene proceeded cleanly and yielded pairs of ketones and carboxylic acids. Two of the hemiperketals yielded only one pair of products while the others produced two sets of products. One of each pair of fragmentation products had undergone skeletal rearrangement. Only methyl migrations were observed when in competition with phenyl groups from the same position. The activation parameter data for ld [ΔH‡ = 24.3 kcal/mol, ΔS‡ = ‐8.4 eu, ΔG‡ = 27.1 kcal/mol, k60°. = 3.1 × 10−5 s−1] were consistent with 0.0 bond scission as the rate‐determining‐step. A likely mechanism for this thermolysis is initial peroxy bond homolysis to the 1,5‐oxygen diradical followed by β‐scissions with rearrangements.
On the synthesis and reactivity of 4,10‐dihydrobenzo‐[b]thieno[2,3‐e]thiepin‐10‐acetic acid and 5,10‐dihydrobenzo[e]thieno[3,2‐b]thiepin‐10‐acetic acid
Authors: Daich A. , Decroix B. 
Published: March 2009

AbstractA simple method to synthesize 4,10‐dihydrobenzo[b]thieno[2,3‐e]thiepin‐10‐acetic acid(8a)and 5,10‐dihydrobenzo[e]thieno[3,2‐b]thiepin‐10‐acetic acid(8b)starting from ketonesla,bis described. The reactivity of the acid8ahas been investigated and some derivatives are reported.
Synthesis, structural, conformational and biochemical study of some 3β‐acyloxytropan‐3α‐carboxylic acid hydrochlorides
Authors: Burgos C. , Gálvez E. , Izquierdo M. L. , Arias M. S. , Sanz‐Aparicio J. , Fonseca I. , López P. 
Published: March 2009

AbstractA series of 3β‐acyloxytropan‐3α‐carboxylic acid hydrochlorides have been synthesized and studied by 1H and 13C nmr spectroscopy, and the crystal structure of 3β‐(3,4,5‐trimethoxybenzoyloxy)tropan‐3α‐carboxylic acid hydrochloride 4c has been determined by X‐ray diffraction. The compounds studied display in methanol‐d4 the same preferred conformation. The pyrrolidine and piperidine rings adopt a flattened N8 envelope and distorted chair conformation; puckered at N8 and flattened at C3 respectively with the N‐substituent in equatorial position with respect to the piperidine ring. In all cases, there is only one mode (axial) of proton uptake at the piperidine nitrogen atom. These results are in close agreement with that found for compound 4c in the crystalline state. The inhibitory ability of the title compounds upon 3H‐GABA binding to sinaptosomal brain membranes is also reported.
Photochemistry of tetramethyl‐4‐pyrone in alcohol solvents
Authors: Pavlik James W. , Keil Elinor B. , Sullivan Eileen L. 
Published: March 2009

AbstractIrradiation of tetramethyl‐4‐pyrone in alcohol solvents leads to the formation of tetramethyl‐2‐pyrone and to a variety of cyclopent‐2‐enone and cyclopent‐3‐enone solvent adducts. The structure and mode of product formation is consistent with photochemical generation of a short‐lived 2,6‐bridged oxabicyclohexenyl zwitterion which undergoes sigmatropic rearrangement to a longer‐lived epoxycyclopentenone. Although the zwitterion is efficiently trapped by methanol solvent, in less nucleophilic alcohol solvents it rearranges to the epoxycyclopentenone which isomerizes to the 2‐pyrone or reacts with the alcohol solvent to form the observed solvent adducts.
Synthesis and properties of methylene‐bis‐(nitraminofurazans)
Authors: Willer Rodney L. , Day Robert S. , Gilardi Richard , George Clifford 
Published: March 2009

AbstractMethylene‐bis‐(3‐aminofurazans) and methylene‐bis‐3‐(nitraminofurazans) with methyl and nitro substituents at the 4‐ and 4′‐positions have been synthesized. The thermal properties and crystal structures of the compounds have been determined. As expected, the methyl‐substituted nitramino compound has better thermal stability than the nitro‐substituted compound. The densities predicted for the compounds by the Holden method and those determined by X‐ray crystallography are in close agreement.
Synthesis of 3,3‐dinitroazetidine from 1‐t‐butyl‐3,3‐dinitroazetidine
Authors: Hiskey Michael A. , Coburn Michael D. , Mitchell Michael A. , Benicewicz Brian C. 
Published: March 2009

AbstractTreatment of 1‐t‐butyl‐3,3‐dinitroazetidine (1) with benzyl chloroformate resulted in a novel elimination of isobutylene to yield equimolar amounts of 1‐(benzyloxycarbonyl)‐3,3‐dinitroazetidine (3) and 1‐t‐butyl‐3,3‐dinitroazetidine hydrochloride. The carbamate 3 was effectively cleaved by trifluoromethanesulfonic acid to yield 3,3‐dinitroazetidinium trifluoromethanesulfonate (4). Free 3,3‐dinitroazetidine (5) has also been isolated.
Syntheses of substituted‐1,2,4‐triazoles
Authors: Shafiee A. , Naghashian F. , Reghabi N. 
Published: March 2009

AbstractStarting from the readily available 3‐phenylpropionitrile, 3‐(or 5‐)(2‐phenethyl)‐1,2,4‐triazole3was prepared. Reaction of compounds3with diazomethane afforded 1‐methyl‐3‐(2‐phenethyl)‐1,2,4‐triazole(4)and 1‐methyl‐5‐(2‐phenethyl)‐1,2,4‐triazole(5). Reaction of compound3with methanesulfonyl chloride, benzenesulfonyl chloride orp‐toluenesulfonyl chloride afforded only one of the expected isomer; namely compounds6, 7 and8respectively.
Synthesis of [1,2,4]triazoloquinazoline and [1,2,4]‐triazolo‐1,4‐benzodiazepine derivatives
Authors: Gatta Franco , Del Giudice Maria Rosaria , Borioni Anna 
Published: March 2009

AbstractSome [1,2,4]triazolo[1,5‐c]quinazolin‐5(6H)‐ones 7, the corresponding isomers [1,2,4]triazolo[4,3‐c]quinazo‐lin‐5(6H)‐ones and the 5‐amino derivatives 8, 9 and 11 have been synthesized starting from the acylamidrazones 5. The preparation of 5H‐[1,2,4]triazolo[1,5‐d]‐1,4‐benzodiazepin‐6(7H)‐ones 15 and of 5‐cyclicaminomethyl‐[1,2,4]triazolo[1,5‐c]quinazolines 16 and 17 is also reported.
Improved synthesis of quinaldines by the skraup reaction
Authors: Song Zhiguo , Mertzman Michael , Hughes David L. 
Published: March 2009

AbstractA series of substituted quinaldines was synthesized with much improved yields from the reaction of croton‐aldehyde and the corresponding anilines using either p‐chloranil or 2,3‐dichloro‐1,4‐naphthoquinone as the oxidant.
Synthesis of Some amino‐4,5‐dihydropyrazolo[3,4‐a]acridines as potential cholinesterase inhibitors
Authors: Shutske Gregory M. , Tomer John D. 
Published: March 2009

AbstractA synthesis of the 4,5‐dihydro derivatives of the previously known pyrazolo[3,4‐a]acridine ring system is described. The reaction of a 3,4‐dihydroacridin‐1(2H)‐one withN,N‐dimethylformamide dimethyl acetal gave a reactive enamino ketone, which yielded the desired heterocycle upon reaction with hydrazine. Using this chemistry, 11‐amino‐4,5‐dihydro‐2H‐pyrazolo[3,4‐a)acridine (3) and a number of its 2‐substituted derivatives4a‐kwere synthesized and evaluated as acetylcholinesterase inhibitors, based on their relationship to 1,2,3,4‐tetrahydro‐9‐acridinamine (THA). 1‐Amino‐4,5‐dihydro‐1H‐pyrazolo[3,4‐a]acridine (11a) and 2‐amino‐4,5‐dihydro‐1H‐pyrazolo[3,4‐a]acridine (11b) were also synthesized and investigated as potential cholinesterase inhibitors.
Synthesis, proton NMR stereochemical study and diels‐alder reaction of (E)‐7‐arylidene‐2H,6H‐naphtho[1,8‐bc]furan‐2,6‐diones
Authors: Bouaziz Zouhair , Fillion Houda , Pinatel Henri 
Published: March 2009

Abstract7‐Arylidene‐2H,6H‐naphtho[1,8‐bc]furan‐2,6‐diones 3 were prepared by a retro‐Diels‐Alder reaction of the corresponding dihydro 1,3‐oxazines 2 or in a one pot synthesis from 6‐hydroxy‐2H‐naphtho[1,8‐bc]furan‐2‐one 1. Their E configuration was established from the chemical shift's values of the vinylic proton and by 1H nmr NOE difference spectroscopy. Cycloadditions of 3b upon styrene or stilbene were catalyzed by boron trifluoride etherate. The cycloadducts were obtained with the relative trans configuration.
Synthesis of tetrahydropyridazino[1,2‐a][1,2,4] benzotriazin‐6‐one derivatives. A novel heterocyclic system
Authors: Ray Partha S. , Buote Joan , Webster Charles A. , Manning Michael J. 
Published: March 2009

AbstractSynthesis of pyridazino[1,2‐a][1,2,4]benzotriazin‐6‐one derivatives involving reaction of either 1,2,3,6‐tetra‐hydropyridazine (9) or hexahydropyridazine 14 with 2‐fluoro‐5‐nitrophenylisocyanate (5) to give, via intramolecular cyclization, 3a and 16 respectively is described. Compound 3a was converted to 18 via methylation and hydroxylation to give 20 followed by conversion to the acetonide derivative 18. Both 16 and 18 were reduced to the amino derivatives 17 and 19 respectively.
Novel perfluoroalkyl‐substituted pyrazoles. 1. Hydroxypyrazoles
Authors: Gaede Bruce J. , Mcdermott Lisa L. 
Published: March 2009

AbstractAddition of methylhydrazine to a variety of haloalkyl‐substituted α,β‐unsaturated esters gives 1,5‐disubstituted 3‐hydroxypyrazoles, in contrast to the more common synthesis from β‐ketoesters, which gives 1,3‐disubstituted 5‐hydroxypyrazoles. This reaction is used to prepare several novel pyrazoles bearing haloalkyl substituents. Criteria for assignment of structures have been developed based on physical and spectroscopic properties of the isomers. The regiochemical preference in this addition is considered on the basis of steric, electronic, and mechanistic factors.
Synthesis of 4‐Amino‐substituted‐6‐hydroxy and 11‐hydroxynaphtho[2,3‐g]quinoline‐5,12‐diones, and the unexpected formation of disubstituted imidazo[4,5,l‐i,j]naphtho[2,3‐g]quinolin‐7‐ones
Authors: Croisy‐Delcey Martine , Bisagni Emile , Huel Christiane 
Published: March 2009

Abstract4‐Chloroquinoline‐5,8‐dione (8a) and 6‐bromo‐4‐chloroquinoline‐5,8‐dione (8b) were reacted with homophthalic anhydride to give tetracyclic compounds 10 and 11 respectively. The 6,11‐dihydroxy derivative 12 was prepared in low yield by photochemical addition of benzocyclobutenedione to 4‐chloroquinoline‐5,8‐dione (8a) and in better yield through a Friedel‐Crafts reaction of phthalic anhydride with 4‐chloro‐5,8‐dimethoxyquinoline (7a). Whereas 4‐chloro‐6‐hydroxynaphtho[2,3‐g]quinoline‐5,12‐dione (11) was substituted by amines in the usual way to the corresponding 4‐amino‐substituted derivatives, 4‐chloro‐11‐hydroxynaph‐tho[2,3‐g]quinoline‐5,12‐dione (10) led to a mixture of 4‐amino derivatives and the unexpected 2,6‐disubstituted‐imidazo[4,5,l‐I‐j]naphtho[2,3‐g]quinolin‐7‐ones, 13a‐b.
Synthesis of C‐24 β‐lactams of bile acids
Authors: Siddiqui Abdul U. , Siddiqui A. H. , Sundara Ramaiah T. 
Published: March 2009

AbstractMethyl 3α‐hydroxy‐5β‐cholan‐24‐oate III and methyl 3α,12α‐dihydroxy‐5β‐cholan‐24‐oate IV were converted into the respective hydrazides V and VI by reaction with hydrazine. These hydrazides were reacted with aryl aldehyde VII to give the corresponding 24‐arylidene‐hydrazides VIII and IX. The reaction of Schiff bases VIII and IX with monochloroacetyl chloride in the presence of triethylamine afforded β‐lactams X‐XI.