bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on pyrrolidinones. Synthesis of N‐acylpyroglutamic acids having bactericide and fungicide properties
Authors: Rigo Benoǐt , Lespagnol Charles , Pauly Marc 
Published: April 2009

AbstractThe best method to prepare N‐acylpyroglutamic acids is to react N,O‐bistrimethylsilylpyroglutamic acid with acid chlorides or a diketene. These acyl acids display bactericide and fungicide properties against several microorganisms.
Temperature and solvent effects on the experimental dipole moments of three crown ethers
Authors: Caswell Lyman R. , Savannunt Diana S. 
Published: April 2009

AbstractDipole moments of 12‐crown‐4, 15‐crown‐5 and 18‐crown‐6 have been measured for solutions in benzene and in cyclohexane at 15, 20, 25, and 30°, using the Guggenheim‐Smith method. The dipole moments of the more common conformers of these crown ethers have also been calculated. The results indicate that these crown ethers exist in solution as mixtures of conformers. The conformational equilibria shift toward the more polar conformers as temperature increases. There is evidence that the more polar conformers of 12‐crown‐4 and 15‐crown‐5 are somewhat more favored in benzene solution than in cyclohexane, possibly as the result of a weak complexation with the former solvent.
Directed lithiation of 4‐halopyridines: Chemoselectivity, regioselectivity and application to synthesis
Authors: Marsais F. , Trécourt F. , Bréant P. , Quéguiner G. 
Published: April 2009

Abstract4‐Chloro and 4‐fluoropyridines were ortho‐lithiated by n‐butyllithium‐TMEDA chelate or lithium diiso‐propylamide at low temperature. The resulting 3‐lithio 4‐halopyridines were reacted with electrophiles which led to various 3,4‐disubstituted pyridines. The versatility of this functionalization is enhanced by the 4‐halogen reactivity towards nucleophiles such as water, methylate and amines. Some of the 3,4‐disubstituted synthons were annelated to naphthyridine, xanthone and coumarin or condensed to Hantsch‐ester or to “chlotrimazol” analogues. Lithiation of 4‐fluoropyridine led in one step to 3,4‐pyridyne, which was trapped by cycloaddition with furans.
Angular heterocycles. A convenient synthesis of azabenzophenothiazines
Authors: Kang W. B. , Nan'ya Seiko , Maekawa Eturǒ , Ueno Yoshio 
Published: April 2009

AbstractThe acid‐catalysed reaction of substituted 1,4‐naphthoquinones with o‐aminoheterocyclic thiones in alcoholic solution afforded substituted monoazabenzo[a]phenothiazin‐5‐ones 4,5 and substituted benzo[a][1,4]diazabenzothiazino[3,2‐c]phenothiazin‐5‐one (6). Some of the resulting compounds were subjected to dehalogenation. The structures of the products were assigned by elemental analysis, 1H‐nmr, and other spectral analysis.
Pyridazines. XXXV. Preparation of some novel pyrimido[4,5‐c]pyridazine derivatives from 3‐alkylamino‐ and 3‐arylamino‐4‐pyridazinecarboxamides
Authors: Haider Norbert , Heinisch Gottfried , Laßnigg Doris 
Published: April 2009

AbstractFacile syntheses of pyrimido[4,5‐c]pyridazine‐5,7(6H,8H)diones 4, pyrimido[4,5‐c]pyridazin‐5(8H)‐ones 7–10, and dihydropyrimido[4,5‐c]pyridazin‐5(6H)ones 5,6 starting from 3‐chloro‐4‐pyridazinecarbonitrile 1 via aminocarbonitriles 2 and aminocarboxamides 3 are described. In addition, a convenient access to the new aminopyridazinecarbonitrile 11 from the chloronitrile 1, employing the tetrazolo[1,5‐b]pyridazine 12 as the key intermediate, is reported.
A hantzsch 1,4‐dihydropyridine synthesis producing an unusual by‐product
Authors: Patterson J. W. , Nelson J. T. 
Published: April 2009

AbstractThe reaction of 2‐acetyl‐1‐(2‐chlorophenyl)‐6‐methylhept‐1‐en‐3‐one (2) with ethyl 3‐aminocrotonate gave an unusual isomer of a 1,4‐dihydropyridine (6), having an exocyclic double bond. The structure and stereochemistry of 6 was established with 1H and 13C nmr spectroscopy.
Selective instability of trifluoromethyl linked to carbon. A prerequisite for new heterocyclizations with ethyl 4,4,4‐trifluoroacetoacetate arylhydrazones
Authors: Pilgram Kurt H. , Skiles Richard D. 
Published: April 2009

AbstractHighly functionalized pyrazoles, 2, and 1H‐pyrazolo[3,4‐d]pyridazinones 3 have been obtained in moderate yields from ethyl 4,4,4‐trifluoroacetoacetate o‐chlorophenylhydrazones 1 by treatment with sodium hydride in aprotic solvents. Treatment of 2 and 3 with sodium ethoxide in ethanol gave bicyclic 5‐(5‐oxopyrazol‐3‐yl)‐pyrazolones 4 and 5 in high yields. The reactions of 1 with sodium hydride which are accompanied by the loss of fluoride ion from one trifluoromethyl group implicate the anchimeric assistance of an N‐deprotonated anion of 1 in the initial reaction step.
Synthesis, characterization and electron impact mass spectrometry of Schiff bases rearranging to oxazoline, thiazoline and thiazole derivatives
Authors: Guerriero Paolo , Bullita Elvio , Vigato Pietro A. , Pelli Beatrice , Traldi Pietro 
Published: April 2009

AbstractA series of oxazoline compounds have been prepared by reaction of 2,6‐diformyl‐4‐chlorophenol, 2,6‐diformylpyridine or 2,5‐diformylthiophen with o‐aminophenol or o‐aminothiophenol respectively. The oxazoline derivatives are stable both in solid state and in solution while the thiazoline derivatives easily oxidize to the corresponding thiazoles. Physico‐chemical data confirm this oxidation process. The 70 eV electron impact induced decomposition pathways of these compounds, obtained with the aid of exact mass measurements, B/E linked scans and collisional spectroscopy, are discussed in detail.
The 13C NMR of monochlorocarbazoles, monochlorotetrahydrocarbazoles and their 9‐methyl derivatives
Authors: Dodsworth David J. , Quesada P. Andres , De Rosa Michael 
Published: April 2009

AbstractThe 13C nmr of monochlorocarbazoles, monochlorotetrahydrocarbazoles and their 9‐methyl derivatives were measured and the chlorine effects at the ipso, ortho, meta, and para carbons determined.
On Triazoles. XIII. The reaction of 5‐benzalimino‐1,2,4‐triazoles with substituted acetyl chlorides
Authors: Reiter József , Pongó László , Sohár Pál , Dvortsák Péter 
Published: April 2009

AbstractThe reaction of Schiff bases prepared from 1‐ and 2‐substituted‐5‐amino‐1,2,4‐triazoles with phenoxyacetyl chlorides in the presence of triethylamine and a mixture of phosphorus oxychloride and dichloroacetic acid in dimethylformamide to yield β‐lactam 4, a dihydro‐1,2,4‐triazolo[4,3‐a]pyrimidine‐5(1H)‐one 5, a 1,2,4‐triazolo[1,5‐a]pyrimidin‐5(3H)‐one 9 and the corresponding 1,2,4‐triazolo[4,3‐a]pyrimidine‐5(1H)‐one 10 derivatives was studied.
Synthesis of 2‐nitro‐L‐tryptophan
Authors: Phillips Robert S. , Cohen Louis A. 
Published: April 2009

AbstractNitration of N‐(trifluoroacetyl)‐L‐tryptophan methyl ester provides 40% of the anticipated 6‐nitro product and 6–7% of the novel 2‐nitro derivative. The latter compound is deprotected with aqueous acid to form 2‐nitro‐L‐tryptophan. Analogous nitration of L‐tryptophan gives only the 6‐nitro product.
A one‐step preparation of pyrido[3,4‐d]pyrimidine ring system by reaction of 5‐formyl‐1,3,6‐trimethyl‐pyrimidine‐2,4(1H,3H)‐dione with primary amines
Authors: Noguchi Michihiko , Sakamoto Kazushige , Nagata Seiji , Kajigaeshi Shoji 
Published: April 2009

Abstract6,7‐Dihydropyrido[3,4‐d]pyrimidine‐2,4(1H,3H)‐diones were obtained in high yields from the reaction of 5‐formyl‐1,3,6‐trimethylpyrimidine‐2,4(1H,3H)‐dione (1) and primary amines. For this pyridopyrimidine synthesis the following reaction pathway is proposed; the [1,5]‐hydrogen shift of 1 gives a 5,6‐dihydro‐5,6‐dimethylenepyrimidine‐2,4(1H,3H)‐dione intermediate. The cycloaddition reaction of the intermediate with aldimines from 1 and the primary amines affords 5,6,7,8‐tetrahydropyrido[3,4‐d]pyrimidine‐2,4(1H,3H)‐diones, which are dehydrated to the final products.
Electron impact mass spectrometry of some 2‐(p‐bromophenyl)‐4,4‐disubstituted‐5(4H)‐oxazolones
Authors: Crisma Marco , Pelli Beatrice , Traldi Pietro 
Published: April 2009

AbstractThe mass spectrometric behaviour of four 2‐(p‐bromophenyl)‐4,4‐disubstituted‐5(4H)‐oxazolones has been investigated using linked scans, mass analyzed ion kinetic energy spectrometry, accurate mass measurements and collisional spectroscopy. The study shows the formation of similar ions in all cases, with the presence of skeletal rearrangements, leading to highly stable product ions.
Pyrido[2,3‐d]pyrimidines and pyrido[2,3‐d; 5‐d′]dipyrimidines as potential chemotherapeutic agents.VIII
Authors: Ram Vishnu J. , Vanden Berghe D. A. , Vlietinck A. J. 
Published: April 2009

AbstractReactions of 5‐dimethylaminomethylene‐6‐imino‐1,3‐dimethyluracil hydrochloride (1) with active methylene compounds2and4yielded bi‐ and tricyclic heterocyclic compounds3and5. All the prepared compounds were screened for chemotherapeutical activities but none were active.
Mass spectral fragmentation patterns of 2,3‐diphenylindole derivatives and dibenzo[ac]carbazoles
Authors: Erra‐Balsells Rosa 
Published: April 2009

AbstractThe electron impact mass spectra of a variety of substituted 2,3‐diphenylindoles have been examined and the major fragmentation routes ascertained. The mass spectra of several dibenzo[ac]carbazoles are also discussed. All of the results allow us to assume that 2,3‐diphenylindoles would not cyclize in the spectrometer upon electron impact.
Synthesis and spectroscopic properties of N‐azolylpropanamides
Authors: De La Cruz Angeles , Elguero Jose , Goya Pilar , Martinez Ana 
Published: April 2009

AbstractFourteen N‐azolylpropanamides have been prepared by Michael addition of azoles on acrylamide. The compounds have been fully characterized by IR and by 1H and 13C‐nmr. The isolated compounds are the most stable derivatives; kinetic compounds were observed but could not be isolated.
Synthesis of 4‐acyl‐and 235 4‐alkenyl‐3,5‐dimethylisothiazole derivatives
Authors: Alberola Angel , Alonso Felisa , Cuadrado Purificación , Sañudo María Carmen 
Published: April 2009

Abstract4‐Acyl‐ and 4‐alkenyl‐3,5‐dimethylisothiazole derivatives, not available by direct electrophilic substitution [1–5] have been prepared from 3,5‐dimethyl‐4‐isothiazolylcarbonitrile 1 and the corresponding aldehyde 2 in satisfactory yields. Both compounds, 1 and 2, are readily obtained from 3,5‐dimethyl‐4‐iodoisothiazole, whose preparation we have previously reported [6].
New synthesis of pyrido[2,3‐d]pyrimidines. III. Nucleophilic substitution on 4‐amino‐2‐halo and 2‐amino‐4‐halo‐5,6‐dihydropyrido[2,3‐d]pyrimidin‐7(8H)‐ones
Authors: Victory Pedro , Crespo Ana , Garriga Miquel , Nomen Rosa 
Published: April 2009

AbstractAs the third step of a new general synthesis of pyrido[2,3‐d]pyrimidines, the substitution of the halogens by several nucleophiles has been carried out. Yields are between good and high in every case, even when 4‐halogenated compounds have a neighbouring methyl group in C5.
Hydroxyiminoisoquinolin‐3(2H)‐ones. 9. Synthesis of some oxazolo[5,4‐c]‐, thiazolo[5,4‐c]‐ and 2,3‐dihydro‐1H‐[1,4]oxazino[2,3‐c]isoquinolines
Authors: Tikk István , Deák Gyula , Sohár Pál , Tamás József 
Published: April 2009

Abstract4‐Acetylamino‐1‐phenyl‐1,4‐dihydro‐3(2H)‐isoquinolinones and 4‐amino‐1‐phenylisoquinolin‐3‐ol, prepared from the corresponding 4‐hydroxyimino compounds, were converted into new isoquinolines containing fused oxazole, thiazole and 1,4‐oxazine rings.
The synthesis of 1‐[(2‐thiazolyl)methyl]quinolones. The reactivity of the methylene bridge at position‐1 and its involvement in the formation of a stable carbon‐nitrogen ylid
Authors: Izzo Patrick T. , Lee Ving J. 
Published: April 2009

AbstractA series of 7‐chloro‐1,4‐dihydro‐6‐fluoro‐1‐[(2‐methylthiazolyl)methyl]‐4‐oxoquinoline carboxylic esters 5 has been prepared. Dehydration of the intermediates 4‐hydroxythiazolines 4 with trifluoroacetic anhydride resulted in the formation of a ylid 11. Evidence for this was obtained by the X‐ray analysis of the analogous product obtained in reactions carried out with 4‐pyridone.
The formation and X‐ray structure of 6a‐trifluoromethyl‐6a, 12‐dihydro[3,1]benzoxazino[2,1‐b][1,3]‐ benzoxazin‐5‐ones, a new heterocyclic ring system
Authors: Aversa Maria C. , Giannetto Placido , Bruno Giuseppe 
Published: April 2009

AbstractFour representatives of the new ring system [3,1]benzoxazino[2,1‐b][1,3]benzoxazine, as determined by X‐ray crystallography, were prepared by reaction of N‐(2‐hydroxybenzyl)anthranilic acids with trifluoroacetic anhydride.
The mechanism of the chapman rearrangement of N‐arylbenzimidate on the basis of the molecular structure established by X‐ray. Part II
Authors: Kimura Michio , Okabayashi Ichizo , Isogai Koji 
Published: April 2009

AbstractDibenz[c,h]acridine (13) was formed directly by the Chapman rearrangement of 2‐methoxycarbonyl‐1‐naphthyl‐N‐1′‐naphthylbenzimidate (11) without isolation of intermediate 12. When the Chapman rearrangement was carried out under mild reaction conditions, the intermediate 12 was isolated in high yield, whose structure was determined by the X‐ray studies. The mechanism of the Chapman rearrangement can be interpreted on the basis of the X‐ray data of 11 and 12.
Preparation and stereochemistry of methyl 3‐(and 4)‐p‐chlorothiophenoxy‐1‐methylpiperidine‐4‐(and 3)‐carboxylates, and cyclization to benzothiopyranopyridinones
Authors: Butt Graeme L. , Deady Leslie W. , Mackay Maureen F. 
Published: April 2009

AbstractThe title piperidines were prepared by (a) methanolysis of the corresponding nitriles and (b) addition of p‐chlorothiophenol to the appropriate tetrahydropyridines. Three esters were obtained with stereochemistry assigned by nmr analysis: 2 [3(a) SAr, 4(e) CO2Me], 5 [4(e) SAr, 3(e) CO2Me], 6 [4(a) SAr, 3(e) CO2Me]. Compounds 2 and 6 cyclized in 70% sulfuric acid. The product structures were established by X‐ray crystallography and, surprisingly, both had trans‐fused rings. Compound 5, however, did not cyclize but gave 4‐(methylthio)chlorobenzene as the sole isolated product.
Acid‐catalyzed reactions of 3‐(α‐hydroxybenzyl)pyrazolo[1,5‐a]pyridines
Authors: Miki Yasuyoshi , Tomii Osamu , Nakao Hayami , Kubo Mayumi , Hachiken Hiroko , Takemura Shoji , Ikeda Masazumi 
Published: April 2009

AbstractTreatment of 3‐(or‐hydroxybenzyl)pyrazolo[1,5‐a]pyridines with trifluoroacetic acid in dichloromethane resulted in the formation of pyrazolo[1,5‐a]pyridines, bis[α‐(pyrazolo[1,5‐a]pyrid‐3‐yl)benzyl] ethers, and phenylbis(pyrazolo[1,5‐a]pyrid‐3‐yl)methanes, depending upon the presence or absence of the substituents at the 2‐ and/or 4‐positions and the reaction conditions employed.
Facile rearrangement of 2‐amino‐3‐carbethoxy‐4‐ethylfuro[3,2‐b]pyridinium cation to 2‐oxo‐3‐cyano‐4‐ethyl‐4H‐furo[3,2‐b]pyridine
Authors: Desideri N. , Manna F. , Stein M. L. 
Published: April 2009

AbstractThe rearrangement of 2‐amino‐3‐carbethoxy‐4‐ethylfuro[3,2‐b]pyridinium iodide in basic solution was studied. The reaction product is 2‐oxo‐3‐cyano‐4‐ethyl‐4H‐furo[3,2‐b]pyridine which was obtained also by alkylation with ethyl iodide and sodium hydride in dimethylformamide of 2‐oxo‐3‐cyano‐3H‐furo[3,2‐b]‐pyridine or of p‐nitrophenyl‐3‐acetoxypyridine‐2‐cyanacetate.
Synthesis of new isoxazole aminoalcohols
Authors: Chiarino D. , Fantucci M. , Sala A. , Veneziani C. 
Published: April 2009

AbstractThe preparation of new 1‐isoxazolyl‐2‐amino‐1‐ethanol derivatives is described starting from the corresponding 1‐isoxazolylethanones. It is also reported the synthesis of 1‐(5‐isoxazolyloxy)‐3‐amino‐2‐propanol compounds starting from the corresponding 5‐haloisoxazoles and the obtainment of 1‐(3‐isoxazolyloxy)‐3‐amino‐2‐propanol compounds starting from the methyl 3‐hydroxy‐5‐isoxazolecarboxylate.
Stereochemistry and bonding in N‐substituted‐2‐phenyl‐3‐cyanoaziridines
Authors: Keifer Paul A. , Nagel Donald L. , Cromwell Norman H. 
Published: April 2009

AbstractA series of ten N‐alkyl(aralkyl)‐2‐phenyl‐3‐cyanoaziridines has been synthesized to continue investigations of the molecular stereochemistry and bonding of functionalized aziridines. Substantial spectroscopic evidence is presented which indicates the presence of stereoselective hyperconjugation between the phenyl and nitrile groups and the aziridine ring. The 1H and 13C nmr chemical shifts are rationalized in terms of the interactions of the substituents on the aziridine ring, and how these interactions vary with the steric bulk of the nitrogen substituents. Various stereoselective coupling constants (1H‐1H and 13C‐1H) are also reported.
The photoreduction of 8‐substituted 5‐deazaflavins and the 5‐deazaflavin catalyzed photoreduction of methyl viologen
Authors: Link Paul A. J. , Van Der Plas Henk C. , Müller Franz 
Published: April 2009

AbstractProlonged illumination of 8‐X‐5‐deazaflavins (X = C1, N(CH3)2, NH2, p‐NH2‐C6H4) in the presence of an electron donor leads to the formation of a 5,5′‐dimer and/or a 6,7‐dihydro compound. The course and rate of these photoreductions were established and discussed in terms of electronic and steric effects, exerted by the substituent at position 8 and the electron donor. Pseudo first‐order kinetics were found to apply to the photoreduction of 8‐X‐5‐deazaflavins (X = Cl, NH2, p‐NH2‐C6H4) while the rate of the photoreduction of 8‐X‐5‐deazaflavin (X = N(CH3)2) appeared to contain an autocatalytic element. The catalytic effect of 8‐X‐5‐deazaflavins in the photoreduction of methyl viologen by EDTA was investigated. The substituent effect on the rate of the 8‐X‐5‐deazaflavin mediated photoreduction of methyl viologen by EDTA was found to be comparable with that on the photoreduction rate of 8‐X‐5‐deazaflavin in the presence of EDTA with the exception of 8‐X‐5‐deazaflavin (X = N(CH3)2), which showed a remarkable relative enhancement of the reactivity towards methyl viologen photoreduction.
Preparation and proton spectra of 1‐aryl‐1,2‐dihydro‐2‐quinolones
Authors: Wawzonek Stanley , Van Truong Thien 
Published: April 2009

Abstract1‐Phenyl‐, 1‐m‐tolyl‐ and 1‐p‐tolyl‐1,2‐dihydro‐2‐quinolone have been prepared by treating the potassium derivative of 1,2‐dihydro‐2‐quinolone with the corresponding aryl bromide in the presence of finely divided copper. The use of o‐bromotoluene in this reaction gave trace amounts of a crystalline material which upon the basis of mass spectrum analysis was assigned 2‐o‐tolyloxyquinoline as a structure. The 1‐aryl groups caused an unusual chemical shift of the 8‐proton to the Δ 6.64–6.70 region. This behavior paralleled that observed for the 7‐proton of 6‐phenyl‐6H‐indeno[1,2‐c]isoquinoline‐5,11‐dione in earlier studies.
Apurinic DNA reactivity: Modelisation of apurinic DNA breakage with phenylhydrazine and formation of a pyrazole adduct
Authors: Vasseur Jean‐Jacques , Rayner Bernard , Imbach Jean‐Louis 
Published: April 2009

AbstractWe have elucidated the exact mechanism of apurinic oligodeoxynucleotide d(Tp[AP]pT) cleavage by phenylhydrazine and shown that the final isolated product is in fact a 3‐substituted derivative of 1‐phenyl‐pyrazole.
Synthesis of fused ring heterocycles from aromatic amines with hydroximoyl chlorides
Authors: Abdelhamid Abdou O. , Párkányi Cyril , Rashid S. M. Khaledur , Lloyd Winston D. 
Published: April 2009

AbstractSubstituted 2‐arylbenzimidazoles, 2‐arylbenzoxazoles and 2‐arylbenzothiazoles were obtained in good yield by the reaction of hydroximoyl chlorides with ortho‐substituted aromatic amines. The benzo moiety of the benzimidazoles was shown by nmr to be symmetrical, indicating that the N‐H group proton of the imidazole ring is exchanging with the water protons in the DMSO‐d6 solvent.
The role of exciplexes in the photoreduction of quinolinemethanols
Authors: Epling Gary A. , Lin Kuei‐Ying , Kumar Anil 
Published: April 2009

AbstractThe photoreduction of a family of quinolinemethanols has been examined both in the presence and absence of exciplex‐forming additives. Photoreduction of the alcohol group and cleavage of the side chain occurs on direct photolysis. However, irradiation with triethylamine led to predominant cleavage of the side chain while irradiation with 1,3‐dicyanobenzene predominantly led to photoreduction of the alcohol functionality. A variety of other experiments supported the involvement of exciplexes in these transformations.
Regioselectivity in methylation and phenylation of the zwitterionic pyrido[2,1‐f]‐as‐triazinium‐1‐ and 3‐olates and thiolates
Authors: Bátori Sándor , Messmer András 
Published: April 2009

AbstractSubstituted derivatives of the title ring system have been synthesized and the regioselectivity in methylation and phenylation of the zwitterionic pyrido[2,1‐f]‐as‐triazinium 1‐ and 3‐olates 4a‐g and 10 and thiolates 7a,b and 12 has been studied by nmr techniques. Depending on the soft or hard nature of the used reagent (methyl iodide, trimethyloxonium hexafluorophosphate or diphenyliodonium tetrafluoroborate), the reaction yielded NMe 5 and/or OMe 6,11a and NPh 14 or OPh 11b products in the case of olates; while thiolates gave NMe 8 and/or SMe 9,13a and SPh 13b, 15 compounds. Mechanistic suggestions are given to rationalize the observed phenomena.
The synthesis of 1‐alkyl‐4a‐(4‐chlorophenyl)‐ 4,4a‐dihydropyrimido[6,1‐a]isoindol‐9(3H)‐one
Authors: Eberle Marcel K. , Brzechffa Leszek 
Published: April 2009

AbstractThe primary amino group of 3‐(2‐aminoethyl)‐3‐(4‐chlorophenyl)‐2,3‐dihydro‐1H‐isoindol‐1‐one (1) was acylated with acetyl chloride, benzoyl chloride and phenyl acetyl chloride to form the amides 2a‐c, respectively. These were cyclized in phosphorus oxychloride to give the 1‐substituted‐4a‐(4‐chlorophenyl)‐4,4a‐dihydropyrimido [6,1‐a]isoindol‐9(3H)‐ones 3a‐c. Heating of 1 in formic acid lead to the formation of 4a‐(4‐chlorophenyl)‐4,4a‐dihydropyrimido[6,1‐a]isoindol‐9(3H) ‐one (3d). Heating of 1 in the presence of phosgene lead to the formation of 4a‐(4‐chlorophenyl)‐2,3,4,4a‐tetrahydropyrimido[6,1‐a]isoindole‐1, 9‐dione (4).
Reactions of hydroxybenzophenone with hydrazines
Authors: Krishnan Raghavan , Lang S. A. , Lin Yang‐I , Wilkinson Raymond G. 
Published: April 2009

AbstractThe reaction of 2,2′,4,4′‐tetrahydroxybenzophenone with hydrazines under different conditions gave the corresponding indazol‐1,3‐benzenediol derivatives. It is an interesting and unique approach to the synthesis of indazoles. However, the reactions of 2‐hydroxybenzophenone and 2,2′‐dihydroxybenzophenone under the same conditions yielded only the hydrazones.
Régio et périsélectivité de réactions de diels‐alder et des cycloadditions dipolaires‐1,3 avec une triazépine‐1,2,4: Approche théorique
Authors: Hasnaoui A. , El Messaoudi M. , El Mouthadi M. , Goupil J.‐M. , Lavergne J.‐P. 
Published: April 2009

AbstractLa cycloaddition de dipoles‐1,3 (mésitonitrile, C,N‐diméthyle nitrone) et de divers diénophiles (DMAD, anhydride maléïque) à la triazépine‐1,2,4 sont péri et régiospécifiques. Abstraction faite du nitrone, l'orientation préférentielle de l'addition est en accord avec les calculs FMO/MNDO.
Synthesis of an optically active 4‐acetoxyazetidinone intermediate for penems and carbapenems
Authors: Häbich Dieter , Hartwig Wolfgang , Born Liborius 
Published: April 2009

AbstractThe synthesis of the novel (3R,4R)‐4‐acetoxy‐3‐[(1S)‐1‐t‐ butyldimethylsilyloxymethyl‐1‐((1S)‐1‐ phenylethylaminocarbonyl)]azetidin‐2‐one (1a), a valuable key intermediate for penems and carbapenems bearing a 6‐hydroxyacetamide side chain, and its diastereomer 1b, from dimethyl cis‐2,3‐oxirane dicarboxylate, is described. The allocation of absolute configurations to the diastereomers 1a and 1b ensued via single‐crystal X‐ray analysis of the isomer 1b.
Synthesis of imidazo[5,4‐d] [1,3]thiazines: X‐ray structure of N‐methyl‐N′‐[5‐(methylamino)‐3‐nonylimidazo[5,4‐d] [1,3]thiazin‐7(3H)‐ylidene]thiourea
Authors: Grözinger Karl G. , Onan Kay D. 
Published: April 2009

AbstractN‐Alkyl‐N′‐[5‐(alkylamino)‐3‐alkylimidazo[5,4‐d] [1,3]thiazin‐7(3H)‐ylidene]thioureas were obtained by the reaction of 1‐substituted 5‐amino‐4‐cyanoimidazoles with alkyl isothiocyanates. The structure of this heterocyclic system was confirmed by single crystal X‐ray diffraction analysis.