bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reduction products of 2‐pyridylmethylene‐1‐indanones. Indanols and indenoindolizines
Authors: Sam Joseph , Alwani Dru W. , Aparajithan K. 
Published: May 2009

AbstractSeveral 2‐pyridylmethylene‐1‐indanones (I) were prepared and reduced to 2‐pyridyl‐methyl‐1‐indanones (II). The reductive cyclization of 5, 6‐dimethoxy‐ and 6‐hydroxy‐5‐methoxy‐2‐pyridylmethylene‐1‐indanone gave the corresponding 5a, 6, 6a, 7, 8, 9, 10, 11a‐octahydroindeno[2, 1‐b]indolizines (X).
A novel 7,6,5‐ring system: Triazolobenzoxazepinone
Authors: Wood Clair G. , Geertsema Abel , Freeburg Linnea , Reardon Edward J. , Jurgens Harold R. , Clapp Leallyn B. 
Published: May 2009

AbstractA new ring system, a triazolobenzoxazepinone, has been synthesized in which the conformation of the 7‐membered ring is rather rigidly imposed by the system. The conformation of the intermediates, nitro‐ and aminobenzoxazepinones, appear to be more sterically hindered than any precursors of the 7, 6‐ring system. The formation of the 7,6‐ and 7,6,5‐ring systems and the preceding transition states must therefore be sterically accelerated through regulation of rotational conformation.
New reactions of pyrroles. II. Preparation and reactions of pyrroleglyoxyloyl derivatives
Authors: Archibald John L. , Freed Meier E. 
Published: May 2009

AbstractPyrroles treated with oxalyl chloride produced pyrroleglyoxyloyl chlorides. Unsubstituted and C‐alkyl pyrroles gave products stable only at low temperatures. N‐Substitution or presence on the ring of an electron withdrawing group (e.g. carbonyl) increased the stability of the glyoxyloyl chlorides considerably. Substitution occurred at the 2‐position unless both 2 and 5 positions of the pyrrole nucleus were blocked. When this was the case substitution occurred slowly at position 3.
Some reactions of 3,6‐disubstituted‐s‐tetrazines; A new synthesis of the 1,2,4‐triazine ring system
Authors: Roffey Patrick , Verge John P. 
Published: May 2009

AbstractThe synthesis of variously substituted pyridazines by 1,4‐cycloaddition of cyclic enol ethers, esters, and some electron‐rich acetylenes is described. Extension of the scheme to include some imino‐ethers as dienophiles resulted in the synthesis of 1,2,4‐triazine derivatives.
Pyrazoles VI: The electron‐releasing capacity of the pyrazole ring
Authors: Wijnberger C. , Habraken Clarisse L. 
Published: May 2009

AbstractUV and PMR spectral data and CO frequencies of some methylpyrazoles containing in the 3‐, 4‐ or 5‐position, a formyl‐, acetyl‐ or ethoxycarbonyl group are reported. These data confirm earlier conclusions that, in particular, the 4‐pyrazolyl group acts as an electron releasing group. The syntheses of a number of formyl‐, acetyl‐ and ethoxycarbonyl pyrazoles are described. In addition, some 4‐dicyanovinyl‐ and 4‐tricyanovinylpyrazoles were investigated.
Studies on the syntheses of heterocyclic compounds. Part CCCXXX Synthesis of a homocularine type compound
Authors: Kametani T. , Terui T. 
Published: May 2009

AbstractAn intramolecular Ullmann reaction of bromophenethylisoquinoline (X) was investigated in order to obtain the homocularine type compound (V), which could be one of the potential alkaloids belonging to 1‐phenethylisoquinoline series. Methylation of the phenolic 8‐hydroxyisoquinoline (XVIII), one of the position isomers which was separated by silica gel chromatography from a mixture of 6‐hydroxy‐ (XVII) and 8‐hydroxyisoquinoline (XVIII) prepared as usual, gave the starting material (X), which was cyclized by the Ullmann reaction in the presence of cupric oxide. The structure of our objective homocularine (V) was assigned from spectral data.
Synthesis of some 5H‐imidazo[4,5‐e]‐as‐triazin‐6‐(7H)ones (6‐azapurin‐8‐ones)
Authors: Yoneda Fumio , Higuchi Masatsugu , Nitta Yoshihiro 
Published: May 2009

AbstractTreatment of 1,3‐dialkyl‐7‐azalumazine derivatives with alcoholic sodium hydroxide caused a benzylic acid type rearrangement followed by decarboxylation and oxidation by air to give the corresponding 5,7‐dialkyl‐5H‐imidazo[4,5‐e]‐as‐triazin‐6‐(7H)ones (7,9‐dialkyl‐6‐azapurin‐8‐ones).
Pyrazoles by dealkylation of pyrazolium salts
Authors: Cross Barrington , Arotin Robert L. , Ruopp Charles F. 
Published: May 2009

AbstractA rapid, convenient conversion of 1,2‐dimethylpyrazolium salts (1) to 1‐methylpyrazoles (2) is accomplished in piperidine or 3‐methylpiperidine at temperatures ≥ 106°. This demethylation represents a particularly useful procedure for the synthesis of 3‐ and 5‐substituted aminopyrazoles, which are not readily obtainable by other methods. The 50:50 mixture of piperidinopyrazole isomers 2b can be obtained directly by treating 3‐chloro‐1,2‐dimethyl‐5‐phenylpyrazolium iodide (3b) with piperidine in ethanol at 106°.
Studies on cycloimmonium ylids. Synthesis of some new 2,4,6‐triaryl‐substituted pyridinesviapyridinium, picolinium and isoquinolinium ylids
Authors: Tewari R. S. , Misra N. K. , Dubey A. K. 
Published: May 2009

AbstractReaction of pyridinium phenacylids and their picolinium and isoquinolinium counterparts with substituted benzylideneacetophenones gave a wide variety of 2,4,6‐triaryl‐substituted pyridines which are expected to have some potential biological activities. Ammonium acetate in glacial acetic acid was used as the cyclization agent. The structures of resulting pyridines are supported by nmr and ir spectral data.
Studies on tertiary amine oxides. LXVIII. . Reactions of aromatic N‐oxides with 2‐substituted 2‐oxazolin‐5‐ones in the presence of acetic anhydride
Authors: Yousif Mohammed M. , Saeki S. , Hamana M. 
Published: May 2009

AbstractQuinoline l‐oxides 1a‐f readily react with 2‐phenyl‐ and 2‐methyl‐2‐oxazolin‐5‐ones, 2a and 2b, in the presence of acetic anhydride to afford 2‐substituted 4‐(2‐quinolyl)‐2‐oxazolin‐5‐ones 3a‐h in good yields. Hydrolysis of 3a‐f with 10% hydrochloric acid under refluxing conditions gives the corresponding 2‐amino‐methylquinoline dihydrochlorides 5a‐e or monohydrochloride 5f also in good yields. Similar results are obtained from reactions of isoquinoline 2‐oxide 9 with 2a,b under the same conditions.
Synthesis of 2,2a,4,5‐tetraazabenz[cd] azulene derivatives
Authors: Imafuku Kimiaki , Sumio Miyuki , Matsumura Hisashi 
Published: May 2009

Abstract3‐Methyl‐1,8‐dihydrocycloheptapyrazol‐8‐one hydrazone (5) reacted with triethyl ortho‐formate, orthoacetate and orthopropionate to afford 2,2a,4,5‐tetraazabenz[cd]azulene derivatives (7a‐c). 3‐Methyl‐ (7b) and 3‐phenyl‐substituted compounds (7d) were also obtained by the reactions of 5 with acetyl and benzoyl chlorides, respectively.
The synthesis of deuterium labeled macrocyclic polyethers (crown ethers)
Authors: Whitney Richard R. , Jaeger David A. 
Published: May 2009

AbstractFive tetradeuterated analogues (1a, 1b, 1c, 1d, and 1e) of 3,6,9,12,15‐pentaoxa‐21‐aza‐bicyclo[15.3.1]heneicosa‐1(21),17,19‐triene (pyridyl‐18‐crown‐6, 1) have been prepared corresponding to the five unique protonated carbon atoms of the polyether cycle. Deuterium labeling was ≥ 99% for four of the compounds and ≥ 97% for the other (1a).
Synthesis of 1‐(5‐phenyl‐2H‐tetrazol‐2‐ylacetyl)‐4‐substituted thiosemicarbazides as possible antiinflammatory agents
Authors: Raman Krishna , Parmar Surendra S. , Singh Shiva P. 
Published: May 2009

AbstractA series of 1‐(5‐phenyl‐2H‐tetrazol‐2‐ylacetyl)‐4‐substituted thiosemicarbazids were prepared as possible antiinflammatory agents. Their antiproteolytic activity was reported.
Synthesis of pyrano[3,4‐c]pyrazole and pyrazolo[3,4‐d][1,2]diazepine derivatives
Authors: Migliara Onofrio , Sprio Vincenzo 
Published: May 2009

AbstractBy the action of thionyl chloride on 3(5)‐R‐4‐phenacylpyrazole‐5(3)‐carboxylic acid (3c,d), 3‐R‐5‐phenylpyrano[3,4‐c]pyrazole‐7‐(1H)ones (4c,d) were obtained. When 4c,d were treated with hydrazine hydrate followed by refluxing in ethanol containing acetic acid, 4,7‐dihydro‐3‐R‐5‐phenylpyrazolo[3,4‐d][1,2]‐diazepin‐8‐(1H)ones (6c,d) were formed. Compounds 6c,d, in turn, were refluxed in ethanol saturated with hydrochloric acid to yield 6‐amino‐1,6‐dihydro‐3‐R‐5‐phenyl‐7H‐pyrazolo[3,4‐c]pyridin‐7‐ones (7c,d). Compounds 7c,d could be obtained directly from 5c,d. The starting materials 3c,d were prepared by hydrolysis of the oxime of 3(5)‐R‐4‐phenacyl‐5(3)carboalcoxypyrazoles (1a,b). Structural assignments rested on correct elemental analysis, molecular weights determined by mass spectrometry, and spectroscopic evidence.
Alkylation des pyrimidines en catalyse par transfert de phase
Authors: Hedayatullah Mir 
Published: May 2009

AbstractNous rapportons ici, la première étude concernant l'alkylation simple et efficace, en catalyse par transfert de phase, de dianions pyrimidiques ambidents dérivés de l'uracile, de la thymine, du nitro‐5 uracile, du fluoro‐5 uracile, du chloro‐6 uracile, de la tétrahydro‐1,2,3,4 dioxo‐2,4 quinazoline, conduisant sélectivement et avec de hauts rendements, aux dérivés N1,N3‐dialkylés correspondants.
Studies in the heterocyclic series. XIX. Synthesis of 1,4‐diazaphenothiazine and its benzo derivatives
Authors: Okafor Charles O. 
Published: May 2009

Abstract1,4‐Diazaphenothiazine, the parent compound of this heterocyclic ring has now been prepared from 2,3‐dichloropyrazine and 2‐aminothiophenol. Replacement of 2,3‐dichloropyrazine with 2,3‐dichloroquinoxaline and 2,3,6‐trichloroquinoxaline led to the corresponding 1,4‐diazabenzo[b]phenothiazine in good yields. Structural assignments were made by spectroscopic studies and by certain chemical transformations.
Pyridinethiones. VI. The synthesis of 2H‐Thiopyrano[2,3‐b]pyridin‐2‐ones
Authors: Christensen Mads ChR. , Becker Jan 
Published: May 2009

AbstractA general and versatile method for the preparation of 2H‐thiopyrano[2,3‐b]pyridin‐2‐ones is described. The starting materials, the β, β‐disubstituted vinyl‐1‐t‐butyl‐2‐(1H)pyridinethiones were prepared from the synthon 3‐formyl‐1‐t‐butyl‐2‐(1H)pyridinethione by condensation. 13H nmr spectra showed the vinyl double bond of the condensation products to have the trans configuration with the smallest group close to the sulfur atom. Some reactions of these new azaanalogues of thiocoumarins are reported.
Synthèse de dérivés indoliques substitués in 7
Authors: Ta Kim Phieo , Guilard Roger , Samreth Soth , Sornay Roland 
Published: May 2009

AbstractLa synthèse et quelques aspects de la réactivité chimique d'acétyl‐7, de benzoyl‐7 et de bromo‐7 indoles sont décrits.
Derivatives of 5,6‐Dimethoxybenzo[b]thiophen‐2‐(3H)one. Synthesis of 5,6‐Dimethoxybenzo[b]thieno[2,3‐b]quinoline
Authors: Camoutsis Charalabos , Catsoulacos Panayotis , Salem G. , Terzis A. , Filippakis S. E. 
Published: May 2009

AbstractSubstituted‐3‐benzylidenebenzo[b]thiophen‐2‐ones have been synthesized. 5,6‐Dimethoxybenzo[b]‐thiophen‐2‐(3H)one with aniline and triethyl orthoformate gives the 3‐anilinomethylene compound, which can be hydrolysed to give the corresponding 3‐hydroxymethylene derivative. Dimethoxybenzo[b]thieno[2,3‐b]‐quinoline has been synthesized.
Synthesis and antifolate activity of 8,10‐dideazaminopterin
Authors: Degraw Joseph I. , Kelly Lawrence F. , Kisliuk Roy L. , Gaumont Yvette , Sirotnak Francis M. 
Published: May 2009

AbstractA synthesis of 8,10‐dideazaminopterin, using 2,4‐diamino‐6‐bromomethyl‐8‐deazapteridine (2) as a key intermediate, is described. Condensation of the triphenylphosphinylide derived from 2 with p‐formylbenzoyl‐L‐glutamate afforded a 9,10‐dehydro‐8,10‐dideazaminopterin ester intermediate 5. Hydrogenation of the olefinic linkage and subsequent hydrolysis of the glutamate ester gave the title compound. 8,10‐Dideazaminopterin was a potent growth inhibitor of folate dependent bacteria. It was 16 times more potent then methotrexate as an inhibitor of dihydrofolate reductase derived from L1210 leukemia cells, and showed strong activity against L1210 in mice.
Synthesis and characterization of ethidium analogs: Emphasis on amino and azido substituents
Authors: Firth William J. , Watkins Charles L. , Graves David E. , Yielding Lerena W. 
Published: May 2009

AbstractA series of eight ethidium derivatives has been synthesized in which the substituents at R3 and R8 have been varied with hydrogen, azido and amino functions. Three of these compounds are new and their synthesis and characterization by uv‐visible, ir and 1H nmr spectroscopy are presented. The synthesis and characterization of the other compounds are also given for comparison, because the compounds served as precursors, or the synthetic route undertaken for these compounds differed from that reported previously.
The synthesis of all of the dimethyldibenzothiophenes and monoethyldibenzothiophenes
Authors: Tedjamulia Marvin L. , Tominaga Yoshinori , Castle Raymond N. , Lee Milton L. 
Published: May 2009

AbstractThe synthesis of all four isomers of the monoethyldibenzothiophenes and all of the sixteen isomers of the dimethyldibenzothiophenes has been accomplished.
Polycyclic nitrogen compounds. Part iii. Synthesis of 3,3a‐dihydrothiazolo[3,4‐α]quinoxalin‐4‐ones
Authors: Adegoke E. A. , Alo Babajide 
Published: May 2009

AbstractNew tricyclic quinoxalinone skeletons with bridge‐head nitrogen atoms and containing sulphur in a fully‐reduced five‐membered ring C were obtained. 3,3a‐Dihydrothiazolo[3,4‐α]quinoxalin‐4‐ones I‐III were prepared by metal‐acid reductive cyclisation of N‐(nitrophenyl)‐ and N‐(dinitrophenyl)thiazolidine‐4‐carboxylic acids IVa,b,c. Attempts to obtain the skeleton by selective hydrogen transfer reductive cyclisation of the corresponding esters Va,b,c were unsuccessful.
Research on heterocyclic compounds. XIII. Synthesis of 4,5‐dihydro‐5‐oxo‐3‐isoxazoleacetic acid and related compounds
Authors: Abignente Enrico , De Caprariis Paolo , Liguori Michele 
Published: May 2009

AbstractSome new 4,5‐dihydro‐5‐oxoisoxazole derivatives were synthesized as part of a study to prepare potential antiinflammatory agents. The reaction of the diethyl ester of 3‐oxopentanedioic acid with hydroxylamine afforded the 3‐hydroxyimino derivative, which was then cyclized to the title compound. This reacted with diazomethane to give a couple of isomeric methyl derivatives, namely methyl 2,5‐dihydro‐2‐methyl‐5‐oxo‐3‐isoxazoleacetate and methyl 5‐methoxy‐3‐isoxazoleacetate. Reaction of these compounds with ammonia gave the corresponding acetamides. All compounds were characterized by elemental analysis, uv, ir, and 1H‐nmr spectra.
An unexpected preparation of 4‐oxo‐2H‐1,3‐benzothiazines
Authors: Golec Frederick A. , Lee Paul , Lloyd John R. 
Published: May 2009

AbstractTreatment of compound N,N‐(dithiobis(3‐chloro‐2,1‐phenylene)dicarbonylbis (N‐cyclopentylglycine)diethyl ester (3) with methanolic sodium hydroxide does not produce the expected hydrolysis product N,N‐(dithiobis‐(3‐chloro‐2,1‐phenylene)dicarbonylbis (N‐cylcopentylglycine) (4) but yields a mixture of compounds 8‐chloro‐3‐cyclopentyl‐3,4‐dihydro‐4‐oxo‐2H‐1,3‐benzothiazine‐2‐carboxylic acid (6) and N‐(3‐chloro‐2‐mercaptobenzoyl)‐N‐cyclopentylglycine (7). This unexpected observation has the potential of a new heterocyclic synthesis method for the 4‐oxo‐2H‐1,3‐benzothiazine class of compounds.
Novel synthesis of pyrido[2,1‐f]‐as‐triazinium system and its zwitterionic derivatives. Different reactivities of 1‐ and 3‐olates with electrophiles
Authors: Bátori S. , Juhász‐Riedl Z. S. , Sándor P. , Messmer A. 
Published: May 2009

AbstractA novel convenient synthesis of the title system has been developed using α‐carbonyl derivatives of N‐aminopyridine and formamide (and its substituted derivatives) in the presence of phosphorus oxychloride or boron trifluoride. Quaternization of zwitterionic 1‐ and 3‐olates (4a, 4b; 11) with soft and hard methylating agents has been studied. Mechanistic suggestion are given to explain the formation of the different (solely N‐Me; N‐Me and O‐Me; solely OMe) products.
Reaction of sulfenes with heterocyclic N,N‐disubstituted α‐aminomethyleneketones. XII. Synthesis of [1]benzothiepino[4,5‐e][1,2]oxathiin derivatives
Authors: Menozzi Giulia , Bargagna Alberto , Mosti Luisa , Schenone Pietro 
Published: May 2009

AbstractThe 1,4‐cycloaddition of sulfene to N,N‐disubstituted (E)‐4‐aminomethylene‐3,4‐dihydro[1]benzothiepin‐5(2H)‐ones I occurred only in the case of aliphatic N,N‐disubstitution to give in good yield 4‐dialkylamino‐3,4,5,6‐tetrahydro[1]benzothiepino[4,5‐e][1,2]oxathiin 2,2‐dioxides, which are derivatives of the new heterocyclic system [1]benzothiepino[4,5‐e][1,2]oxathiin. Also the reaction of I with chlorosulfene occurred only in the case of aliphatic N,N‐disubstitution to afford chiefly trans‐4‐dialkylamino‐3‐chloro‐3,4,5,6‐tetrahydro‐[1]benzothiepino[4,5‐e][1,2]oxathiin 2,2‐dioxides III in satisfactory yield. Adducts III were dehydrochlorinated with DBN to 4‐dialkylamino‐5,6‐dihydro[1]benzothiepino[4,5‐e][1,2]oxathiin 2,2‐dioxides in good yield.
Pyrrolidine‐2,3‐dione, 1‐allylpyrrolidine‐2,3‐dione and 1‐ethoxypyrrolidine‐2,3‐dione
Authors: Sundberg Richard J. , Pearce Bradley C. , Laurino Joseph P. 
Published: May 2009

AbstractAuthentic pyrrolidine‐2,3‐dione has been prepared by two different routes. It is shown that the material previously reported is actually a hydrolysis product, 4‐amino‐2‐oxobutyric acid. 1‐Allyl‐ and 1‐ethoxypyrroli‐dine‐2,3‐dione have been prepared as N‐protected pyrrolidine‐2,3‐diones potentially useful in synthesis.
Reinvestigation of the reported preparation of 3‐(4‐nitrophenyl)thiazolo[2,3‐c][1,2,4]triazepines
Authors: Peet Norton P. , Sunder Shyam 
Published: May 2009

Abstract2‐(1H‐Pyrazol‐1‐yl)‐4‐(4‐nitrophenyl)thiazoles 2a and 2b, resulting from the condensation of 2‐hydrazino‐4‐(4‐nitrophenyl)thiazole (1) and acetylacetone and dibenzoylmethane, respectively, were previously [4] misas‐signed as 3‐(4‐nitrophenyl)thiazolo[2,3‐c][1,2,4]triazepines 3a and 3b. The assignments were corrected by authentic syntheses of 2a and 2b from 2‐chloro‐5‐(4‐nitrophenyl)thiazole (6) and 3,5‐dimethyl‐1H‐pyrazole and 3,5‐diphenyl‐1H‐pyrazole, respectively. In addition, the mass spectrum of 2a is reported. An apparent ionmolecule reaction produces an ion of significant intensity at m/e 394.
Modification of pyridine‐3‐carboxamide (nicotinamide) by radical substitution
Authors: Tada Masaru , Yokoi Yurie 
Published: May 2009

AbstractPyridine‐3‐carboxamide (1) was reacted with alkyl radicals to give mono‐, di‐, and tri‐alkylated products. The t‐butyl radical gives only 6‐t‐butylpyridine‐3‐carboxamide (4a). The reactivity decreases in the order of t‐butyl, isopropyl, and ethyl radicals. The product 4a reacts further with the 2‐phthalimidoethyl radical to give 2‐ and 4‐substituted products 9 and 10, which were transformed into tetrahydronaphthyridinone derivatives 11 and 12.
Synthesis of novel dihydro‐2H‐1,2,4‐oxadiazin‐5(6H)‐ones
Authors: Ürögdi László , Kisfaludy Lajos , Patthy Ágnes , Moravcsik Ernö , Tüdös Helga , Tegyei Zsuzsanna , Ötvös László 
Published: May 2009

AbstractThe title compounds 4 were synthesized via the acid‐catalyzed reaction of α‐(acylaminooxy)carboxylic acid amides 6 with carbonyl compounds, and controlled catalytic hydrogenation of the resulting 2‐benzyloxy‐carbonyldihydro‐2H‐1,2,4‐oxadiazin‐5(6H)‐ones 7 (R6 = PhCH2O).
Novel resolution of chiral lactams
Authors: Ürögdi László , Kisfaludy Lajos , Patthy Ágnes , Vezér Csilla 
Published: May 2009

AbstractA practical method of resolving chiral lactams, e.g. 1, has been evolved, based on the hydroxymethylation of the lactam, followed by esterification of the product 2 with an optically active N‐protected amino acid derivative, e.g. N‐benzyloxycarbonylphenylalanine pentafluorophenyl ester 3. Chromatographic separation of the unreacted hydroxymethylated lactam 2 and the ester 4 and subsequent dehydroxymethylation of the former and aminolysis of the latter afforded pure enantiomer, (R)‐1 and (S)‐1.
Differentiation of isomeric 1‐, 3‐ and 7‐deazaadenosines by electron ionization mass spectrometry
Authors: Reddy A. Mahender , Reimer Mark L. J. , Schram Karl H. , Grifantini Mario , Cristalli Gloria 
Published: May 2009

AbstractThe low and high resolution electron ionization mass spectra of 1‐deazaadenosine, 3‐deazaadenosine and 7‐deazaadenosine are reported. Fragmentation pathways and ion structures are proposed with the aid of linked‐scan, daughter‐ion spectra. Results indicate that the N‐3 position of the purine ring serves as an important acceptor site in fragmentation processes involving hydrogen transfer from the sugar to the base. A mixture analysis of the trimethylsilyl derivatives of adenosine, 1‐, 3‐ and 7‐deazaadenosine by combined gas chromatography/mass spectrometry is also described.
S,N‐heterocycles 2. A convenient, one‐pot synthesis of 2‐alkylamino‐4H‐1,3,4‐benzothiadiazines
Authors: Sanemitsu Yuzuru , Manabe Akio , Kawamura Shinichi , Satoh Junichi , Tanabe Yoo 
Published: May 2009

Abstract2‐Alkylamino‐4H‐1,3,4‐benzothiadiazines 3 are prepared in a one‐pot synthesis from 1‐phenyl‐3‐thiosemi‐carbazides 1 and bromine through an oxidative cyclization.
The synthesis of aryl 4‐nitro‐5‐imidazolyl sulfone radiation sensitizers sterically protected against glutathione reaction
Authors: Egolf Roger A. , Heindel Ned D. 
Published: May 2009

Abstract2,6‐Disubstituted aryl 1‐methyl‐4‐nitro‐5‐imidazolyl sulfones 4 and aryl 1‐neopentyl‐2‐tert‐butyl‐4‐nitro‐5‐imidazolyl sulfones 10 have been synthesized and tested as radiation sensitizers of hypoxic carcinoma cells. These sterically crowded imidazoles show decreased displacement reactivity with glutathione at C‐5, a major metabolic reaction known to deplete effective plasma drug levels in traditional aryl imidazolyl sulfone radiation sensitizers.
Selective N‐1 alkylation of unsymmetrically substituted pyrazoles
Authors: Malhotra Nageshwar , Fält‐Hansen Birgitte , Becher Jan 
Published: May 2009

AbstractA series of C‐substituted pyrazoles have been N‐alkylated. The alkylation occurs preferentially at the N‐1 position when a tert‐butyl group is present at the pyrazole C‐3 position.
A simple aza wittig‐mediated pyrimidine annulation reaction
Authors: Taylor Edward C. , Patel Mona 
Published: May 2009

AbstractTreatment of heterocyclico‐aminonitriles ando‐aminoesters1a‐5awith dibromotriphenylphosphorane gives iminophosphoranes1b‐5bwhich undergo a facile aza‐Wittig reaction at room temperature with phenyl isocyanate to provide the carbodiimides1c‐5c. Treatment of the latter intermediates with ammonia leads to intramolecular ring closure of the initially formed guanidines to provide the fused 4‐aminopyrimidines and 4(3H)‐pyrimidinones1d‐Sd.
Action of (2‐benzothiazolyl)methyllithium with organic polar functions
Authors: Costa Maria Virginia , Brembilla Alain , Roizard Denis , Lochon Pierre 
Published: May 2009

Abstract(2‐Benzothiazolyl)methyllithium reacts quickly at low temperature (‐78°) with a variety of organic electrophiles like aldehydes, ketones, carboxylic esters, nitriles and acyl chlorides. Such reactions lead to an easy introduction of alcohol, keto‐enol or amine‐enamine functional groups in extracyclic position with a stereoselective preference. These polyfunctional compounds whose synthesis is difficult by other pathways, are interesting, in particular, because of their ability to form intramolecular hydrogen bonds.
On the synthesis of geminally functionalized heterocyclic aminocarboxylic acid esters
Authors: Coutouli‐Argyropoulou E. , Thessalonikeos E. 
Published: May 2009

AbstractThe title compounds 5 can be easily obtained by two alternative procedures: 1,3‐dipolar cycloaddition to benzamidocinnamates 3 prepared by methanolysis of the corresponding oxazolones 1 or methanolysis of the spirooxazolones 4 synthesized by 1,3‐dipolar cycloaddition to oxazolones 1. Both reaction sequences show the same stereo and regioselectivity.