bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bromination of 2,1,3‐benzothiadiazoles
Authors: Pilgram Kurt , Zupan Mike , Skiles Richard 
Published: March 2009

AbstractThe bromination of 2,1,3‐benzothiadiazoles in 47% hydrobromic acid at elevated temperature has led to a general preparative method for the synthesis in high yield of otherwise difficulty accessible brominated 2,1,3‐benzothiadiazoles. The typical addition reaction is apparently eliminated under these reaction conditions and substitution takes place exclusively. Bromination of 2,1,3‐benzothiadiazole occurs successively at positions 4 and 7. 4‐Substituted 2,1,3‐benzothia‐diazoles are selectively brominated at position 7. 5‐Bromo‐ and 5‐methyl‐2,1,3‐benzothiadiazole are brominated consecutively at positions 4 and 7.
Pyrroles and pyrazolines from the ring closure of azines
Authors: Stopfer Christian H. , D'Andrea Richard W. 
Published: March 2009

AbstractAlkyl substituted pyrroles and pyrazolines are obtained in good yields by catalytic ring closure of azines, using nickel or cobalt (II) halides as catalysts. The specificity of the reaction is determined by the structure of the azines and a notable exception is discussed.
Some N‐substituted 2‐amino‐ and 2‐methylquinoline‐3,4‐dicarboximides
Authors: Campaigne E. , Hutchinson J. H. 
Published: March 2009

AbstractThe reaction of sodium 2‐amino‐3‐cyanoquinoline‐4‐carboxylate and 2‐methyl‐3‐cyanoquino‐line‐4‐carboxylic acid in polyphosphoric acid led to 2‐amino‐ and 2‐methylquinoline‐3,4‐dicar‐boximide, respectively. Both of these compounds undergo imide N‐alkylation reactions with methyl iodide and various chloroalkylaminodialkyl amines, while the latter also condenses with 3,4‐dichlorobenzaldehyde to form styryl derivatives. Although some of these compounds may be considered structural analogs of the antimalarial 4‐quinolinemethanols, none exhibited antimalarial activity.
The NMR spectral characteristics of some meso‐Ionic s‐triazoles
Authors: Smith Richard F. , Deutsch John L. , Almeter Patricia A. , Johnson Donald S. , Roblyer Suzanne M. , Rosenthal Thomas C. 
Published: March 2009

AbstractThe hetero‐ring proton of anhydro‐1,4‐diphenyl‐3‐mercapto‐s‐triazolium hydroxide (I) is more highly deshielded than its 3‐hydroxy analog (II). The chemical shifts of the hetero‐ring proton for compounds I and II were found to be solvent dependent due to hydrogen bond formation. Two series of anhydro‐1,4‐diaryl‐3‐hydroxy‐s‐triazolium hydroxides have been synthesized and their NMR spectra determined. The chemical shift of the hetero‐ring proton of these compounds was found to correlate with the Hammett sigma constants of the meta‐ and para‐ substituents in the aryl groups.
The crystal and molecular structure of 1,1,4,4‐tetraethyl‐2,5‐dimethyl‐1,4‐diphosphoniacyclohexadiene‐1,4‐dibromide
Authors: Towns R. L. R. , Majeste R. , Brown J. N. , Trefonas L. M. 
Published: March 2009

AbstractThe structure of the title compound has been determined by a single‐crystal, x‐ray diffraction study. The compound crystallizes in a monoclinic unit cell (P21/c) with two molecules per unit cell. Least‐squared lattice parameters are: a = 7.164 ± 0.001Å, b = 14.770 ± 0.001Å, c = 10.562 ± 0.001Å, and β = 124.95 ± 0.01°. The structure parameters refined to a value of R=0.062, excluding hydrogens, for the 1475 statistically significant reflections. The structure determination confirmed that the compound is indeed a diene and not a delocalized structure. The ring is planar but the ethyl groups extend over the ring in an unusual crab‐like fashion.
Mass spectral fragmentation mechanisms of some dibenzo[c,f][1,2] diazepines
Authors: Casey Adria C. , Green James H. , Lee Agnes , Mautner Michael 
Published: March 2009

AbstractThe fragmentation mechanisms of 11H‐dibenzo[c,f][1,2]diazepine (I), its 3,8‐dichloro derivative (II), 3,8‐dichlorodibenzo[c,f] [1,2]diazepin‐11‐one (III) and 3,8‐dichloro‐11H‐dibenzo‐[c,f][1,2]diazepin‐N‐oxide (IV) are discussed. The initial loss of molecular nitrogen is characteristic of I, II and III. Compound IV has a strong molecular ion, that competitively eliminates cither NO or Cl‐ and N2O. The common radical ion, m/166 e present in the mass spectra of I, fluorene, 2‐methyl‐9,10‐anthraquinone and 2‐methylbenzo[c]cinnoline, appears to be formed in different states.
Cyclophosphamides from aminosugars and aminonucleosides
Authors: Fujiwara Allan N. , Acton Edward M. , Goodman Leon 
Published: March 2009

AbstractCondensation of bis‐(2‐chloroethyl)phosphoramidic dichloride with 3′‐amino‐3′‐deoxy‐N,N‐dimethyladenosine afforded the 2′,3′‐cyclicphosphorodiamidate (III). By an improved synthesis, methyl 3‐amino‐3‐deoxy‐β‐D‐ribofuranoside was obtained as a model compound for conversion to the analogous 2,3‐cyclicphosphorodiamidate (XII). Existence of the latter as two diastereomers due to phosphorus asymmetry was shown by nmr analysis, using comparison with the 5‐(O‐p‐nitrobenzoate) (XIII) as a basis for assignments.
The molecular structure of 1,1‐dimethyl‐3‐phenylpyrazolium‐5‐oxide
Authors: De Camp Wilson H. , Stewart James M. 
Published: March 2009

AbstractThe molecular structure of 1,1‐dimethyl‐3‐phenylpyrazolium‐5‐oxide has been determined by a single crystal x‐ray diffraction study. The crystals are monoclinic, space group P21/a, with unit cell dimensions a = 12.630 (5) Å, b = 6.644 (1) Å, c = 12.486 (5) Å, β = 99.17 (2)°. The final R value was 0.049 for 2930 reflections. The bond lengths and angles suggest that a significant contribution to the structure is made by a resonance form in which one of the ring bonds does not exist. No close intermolecular approaches were found.
Intramolecular cyclization of N′‐chloroacetylsalicylhydrazide
Authors: Gaozza C. H. , Lamdan S. 
Published: March 2009

AbstractTreatment of N′‐chloroacetylsalicylhydrazide (I) with sodium hydroxide in dimethylformamide produces an intramolecular cyclization. Of all theoretically possible reactions, only one proceeds to give 5,6‐dihydro‐2‐o‐hydroxyphenyl‐4H‐1,3,4‐oxadiazin‐5‐one (II). No formation of the 1,4,5‐benzoxadiazocin‐3,6‐dione (III) is detected. The structure of II, as well as of its acetylation, methylation and hydrolysis derivatives are discussed.
P.M.R. analysis of several phosphorylated aziridines
Authors: Berlin K. Darrell , Rengaraju S. , Clark Peter E. 
Published: March 2009

AbstractSeveral new phosphorylated aziridines of related structure were prepared. P.m.r. analysis via decoupling experiments provided cis H‐H, trans H‐H, gem H‐H and PNCH coupling values. Similar to simple aziridines, the cis H‐H coupling is larger than trans H‐H coupling (on vicinal ring carbons) which in turn is larger than gem H‐H coupling. In one example operating at 100 MHz and 0° it was possible to detect the presence of two invertomers.
5H‐Thiazolo [3,2‐b]‐ and 2H‐Thiazolo [2,3‐c]‐as‐triazines
Authors: Trepanier Donald L. , Krieger Paul E. 
Published: March 2009

AbstractDerivatives of the 5H‐thiazolo[3,2‐b]‐ and 2H‐thiazolo[2,3‐c]‐as‐triazine systems were synthesized via condensation of tetrahydro‐I‐methyl‐as‐triazine‐3(2H)‐thione with ethylene dibromide and ethyl bromoacetate, respectively. An hypothesis is given for the formation of the [3,2‐b] system in one of these reactions and the [2,3‐c] system in the other. Structure proof was accomplished by an unequivocal synthesis of one of the [2,3‐c] derivatives.
Syntheses of N‐(2,4‐Dinitrophenyl)nitroazoles
Authors: Khan Misbahul Ain , Lynch Brian M. 
Published: March 2009

AbstractSeveral N‐(2,4‐dinitrophenyl)nitroazoles which cannot be obtained by direct nitration of N‐phenylazoles have been prepared by condensation of 2,4‐dinitrofluorobenzene with the appropriate nitroazoles. The structures of the products are assigned on the basis of their proton magnetic resonance spectra; in all the examples studied, condensations occur at positions remote from the nitro group of the nitroazole.
Heterocyclic N‐Glycosides. VI. The reaction of glycosyl azides with propiolic acid and methyl propiolate
Authors: Alonso G. , Garcia‐López M. T. , Garcia‐Muñoz G. , Madroñero R. , Rico M. 
Published: March 2009

AbstractThe synthesis of a series of N‐glycosyl‐v‐triazoles has been accomplished by the 1,3‐dipolar cycloaddition of several glycosyl azides to methyl propiolate and propiolic acid. In most of the cases the two isomeric v‐triazoles were obtained. Structural and anomeric configuration assignments for the N‐glycosides obtained were made on the basis of NMR data. None of the compounds possessed appreciable biological activity against HeLa cells in culture and mouse Sarcoma 180.
The amidoalkylation of aromatic compounds and olefins with 5‐alkoxyhydantoins
Authors: Ben‐Ishai D. , Ben‐Et G. , Warshawsky A. 
Published: March 2009

Abstract5‐Butoxyhydantoin (2a), 3‐benzyl‐5‐methoxyhydantoin (2b) and 3‐p‐chlorophenyl‐5‐methoxy hydantoin (2c) were found to react, in the presence of an acid catalyst, with aromatic compounds and olefins to give 5‐arylhydantoin (3) and 5‐alkylhydantoins with an unsaturated side chain. Isomers which differ in the location of the double bond (4,5,6) as well as cis‐trans isomers were isolated and characterized.
The crystal and molecular structure of 1‐(p‐iodobenzenesulfonyl)‐1‐azaspiro[2,5] octane
Authors: Zacharis H. M. , Trefonas L. M. 
Published: March 2009

AbstractThe structure of 1‐(p‐iodobenzenesulfonyl)‐1‐azaspiro[2.5]octane was determined by a single‐crystal x‐ray diffraction study. The compound crystallizes in the orthorhombic space group P21 21 21 with cell dimensions: a = 11.655, b = 11.825, c = 11.068 ± 0.002 Å. The aziridine ring is spiro‐fused to the cyclohexane ring with the nitrogen atom occupying the equatorial position. The cyclohexane ring is in an undistorted chair conformation and forms a dihedral angle of 97.1° with the aziridine ring. The structure was refined to a final value of R = 0.074 for the 590 independent reflections.
The crystal and molecular structure of 9‐(p‐lodophenyl)‐9‐azatetracyclo[5.3.1.02,6 .08,10] undec‐4‐ene
Authors: Brown J. N. , Towns R. L. R. , Trefonas L. M. 
Published: March 2009

AbstractThe crystal and molecular structure of 9‐(p‐iodophenyl)‐9‐azatetracyclo[5.3.1.02,6 .08,10]‐undec‐4‐ene (C16H16IN) has been determined by single crystal x‐ray diffraction methods. The compound crystallizes in space group P21, (no. 4) with unit cell constants: a = 11.269 (1), b = 7.607 (1), c = 16.714 (1) Å, β = 104.73 (1)°. The structure was solved by the heavy‐atom method and refined by block‐diagonal least‐squares to a final R‐value of 0.054 for the 1546 independently measured, statistically significant reflections. The aziridine ring is fused to the norbornyl rather than to the five‐membered ring as previously assumed. The nitrogen to phenyl‐carbon distance is 1.406 Å and indicates a significant amount of double bond character.
The synthesis and PMR study of certain 3‐substituted 2‐(β‐D‐Ribofuranosyl)indazoles
Authors: Revankar Ganapathi R. , Townsend Leroy B. 
Published: March 2009

AbstractThe synthesis of 3‐cyano‐2‐(β‐D‐ribofuranosyl)indazole (4) has been accomplished by a condensation of N‐trimethylsilyl‐3‐cyanoindazole (1) with 2,3,5‐tri‐O‐aeetyl‐D‐ribofuranosyl bromide (2) followed by subsequent deacetylation. The reactivity of the 3‐cyano group was demonstrated by the conversion of 4 to 2‐(β‐D‐ribofuranosyl)indazole‐3‐carboxamide (5) and 2‐(β‐D‐ribofuranosyl)indazole‐3‐thiocarboxamide (6). The site of ribosylation and the assignment of anomeric configuration for 4 is discussed. The magnetic anisotropy effect of the exocyclic group at C3 on the anomeric proton as determined by pmr spectroscopy is discussed.
Condensed thiophenes from sulfur bridging. I. Phenanthro[4,5‐bcd]thiophene
Authors: Klemm L. H. , Mccoy D. R. , Olson D. R. 
Published: March 2009

AbstractTreatment of phenanthrene with hydrogen sulfide and an alumina catalyst at 630° gives phenthro[4,5‐bcd]thiophene (XVII). Spectral properties of XVII, its sulfoxide, and its sulfone are presented. Other examples of the direct insertion of a sulfur bridging atom into an aromatic molecule are reviewed.
Reactions of some 4‐dicyanomethylenepyran derivatives with malononitrile and hydrazines
Authors: Vanallan J. A. , Petropoulos C. C. , Reynolds G. A. , Maier D. P. 
Published: March 2009

Abstract4‐Dicyanomethylene‐2‐phenyl‐4H‐benzo[b]pyran, the corresponding thiapyran, and 4‐dicyanomethylene‐2,6‐diphenyl‐4H‐pyran react with malononilrile under basic conditions to give 5‐amino‐4‐cyano‐2‐phenylbenzo[b]pyrano[4,3,2‐de] [1,6]naphthyridine, the corresponding thia‐pyranonaphthyridine derivative, and 5‐amino‐6‐cyano‐2,8‐diphenylpyrano[4,3,2‐de] [1,6]naphthyridine, respectively. Certain other related reactions were studied in the course of investigating the above reactions. Hydrazine hydrate and 4‐dicyanomethylene‐2‐phenyl‐4H‐benzo[b]pyran gave 5‐(2‐hydroxyphenyl)‐3‐phenylpyrazole, and phenylhydrazine gave 5‐(2‐hydroxyphenyl)‐1,3‐diphenylpyrazole.
A new route to 2‐styrylbenzimidazoles
Authors: Balazs Marjorie K. , Furst Arthur 
Published: March 2009

AbstractAn attempt was made to prepare 2‐benzylquinoxalin‐3‐one by hydrolyzing the azlactone, 2‐phenyl‐4‐benzylidene‐5‐oxazolone to β‐phenylpyruvic acid and then treating this in situ with o‐phenylenediamine (OPDA). The initial hydrolysis apparantly proceeded only as far as opening the azlactone ring forming 2‐benzamidocinnamic acid which condensed with OPDA to form a substituted styrylbenzimidazole.
6‐Aryl‐1‐azabicyclo [5.4.0] undecanes
Authors: Aboul‐Enein M. Nabil , Sam J. 
Published: March 2009

AbstractSome 6‐aryl‐6‐hydroxy‐l‐azabicyclo[5.4.0]undecanes and their esters were synthesized as potential cardiovascular agents and analgetics of the proheptazine type, respectively. Also, 6‐aryl‐1‐azabicyclo[5.4.0]undecanes were prepared as rigid structures related to the phenethylamine CNS stimulants.
3‐Methylpyrazolo [1,2‐a] pyridazin‐1‐one. Selenium derivatives of 5,8‐dihydropyrazolo[1,2‐a]pyridazine
Authors: Farnum Donald G. , Au Andrew T. , Rasheed Khalid 
Published: March 2009

AbstractThe dehydrogenation of the known 3‐methyl‐5,8‐dihydropyrazolo[1,2‐a]pyridazin‐1‐one (2) to the ten π electron heteroaromatic 3‐methylpyrazolo[1,2‐a]pyridazin‐1‐one (3) is reported. Conversions of the pyrazolone 2 to the pyrazoloselenone 6 via the chloropyrazolium chloride 7, and of pyrazolones 2 and 3 and pyrazoloselenone 6 into the corresponding O or Se ethyl pyrazolium fluoroborates 5, 4, and 8 by triethyloxonium fluoroborate are also described.
Chemical constitution and activity of bipyridylium herbicides. Part VII. 6‐Substituted derivatives of 6,7‐dihydrodipyrido[1,2‐a:2′,1′‐c] pyrazinediium dibromide (diquat) and dipyrido[1.,2‐a:2′,1′‐c] pyrazinediium dibromide
Authors: Black A. L. , Summers L. A. 
Published: March 2009

Abstract6‐Methyl, 6,6‐dimethyl‐, and 6‐phenyl‐6,7‐dihydrodipyrido[1,2‐a:2, 1 ‐c]pyrazinediium dibro‐mides are reversible one electron transfer systems with similar redox potentials to diquat dibromide. They are respectively about one‐half, one‐fourteenth and one‐fiftieth as active as diquat as post‐emergent herbicides and this finding illustrates the importance of molecular size in determining whether bipyridylium salts have outstanding phytotoxic activity. This conclusion is supported by a study of 6‐methyl‐ and 6‐phenyldipyrido[1,2‐a:2′,1 ‐c]pyrazinediium dibromides.
Structural modification studies of 3‐piperonylsydnone. III. Some analogs of 3‐piperonylsydnone and 2,4‐diamino‐5‐piperonylpyrimidine
Authors: Mccaustland Daniel J. , Burton William H. , Cheng C. C. 
Published: March 2009

AbstractIn a continued structural modification study of the antimalarial compounds 3‐piperonylsydnone and 2,4‐diamino‐5‐piperonylpyrimidine, the related piperonyl derivatives of ψ‐1,2,3;4‐oxatriazole, ψ‐1,3,5‐oxadiazole, pyrazole, tetrazole, 1,2,4‐triazine, pyrrolidine, amino‐ and sulfamoyl‐1,2,4‐triazole, as well as some sydnones and diaminopyrimidines with side chains other than the piperonyl group have been synthesized. 3‐(3,4‐Ethylenedioxyphenyl)sydnone was found to double the survival time of Plasmodium berghei infected mice. The other compounds are not as active.
Mass spectra of pyrazine N‐oxides. Studies on pyrazine derivatives. III
Authors: Uchimaru F. , Okada S. , Kosasayama A. , Konno T. 
Published: March 2009

AbstractThe mass spectra of pyrazine 4‐ and 1‐oxides, their di‐N‐oxides and corresponding pyrazines have been determined. The fragmentations induced by electron impact were examined by means of deuterium labeling and high‐resolution measurements. The most pronounced feature of the spectra was the appearance of M‐16 ion peaks. In the case of the methyl and methoxy derivatives of 1‐oxides, the intensity ratio of M‐17/M‐16 was larger than in the 4‐oxides.
Base‐ and acid‐catalyzed condensation reactions of reissert compounds with vinylpyridines
Authors: Giridhar Vaidyanath , Mcewen William E. 
Published: March 2009

AbstractThe hydrochloric acid‐catalyzed condensation of 2‐p‐anisoyl‐1,2‐dihydroisoquinaldonitrile (3) with 2‐vinylpyridine gave 2‐(1‐isoquinolyl)‐3‐(2‐pyridyl)‐5‐p‐anisylpyrrole (4), and the corresponding reaction of 3 with 4‐vinylpyridine afforded 2‐(1‐isoquinolyl)‐3‐(4‐pyridyl)‐5‐p‐anisylpyrrole (5). The condensation of the lithium salt of 3 with 4‐vinylpyridine gave α‐(4‐pyridyl)‐β‐(1‐iso‐quinolyl)‐p‐methoxypropiophenone (10), which was cyclized to 2‐(4‐pyridyl)‐3‐p‐anisylpyrrolo‐[2,1‐a]isoquinoline (7) by the action of concentrated hydrochloric acid. 2‐(4‐Pyridyl)‐3‐phenyl‐pyrrolo[2,1‐a]isoquinoline (6) and 2‐(2‐pyridyl)‐3‐p‐anisylpyrrolo[2,1‐a]isoquinoline (8) were prepared by analogous sequences of reactions.
Geometrical isomorism of ethyl N‐(pyrimidinyl) aminomethylenceyanoacetates
Authors: Nishigaki Sadao , Ogiwara Kazuko , Yoneda Fumio 
Published: March 2009

AbstractThe geometrical isomers of ethyl N‐(Pyrimidinyl)a minomethylenecy anoacetates were isolated and their structures and interconversions are discussed.
Mass spectra of some 2‐, 3‐, and 4‐pyridinecarboxylic acids. Further evidence of a N‐H interaction for loss of carbon dioxide
Authors: Brown Ellis V. , Moser Russell J. 
Published: March 2009

AbstractMass spectra of 3‐acetamido‐, 3‐methoxy‐, and 4‐methoxy‐2‐pyridinecarboxylic acids, 2,6‐pyridinedicarboxylic acid, 4‐nitro‐2‐pyridinecarboxylic acid N‐oxide, 2‐chloro‐ and 2‐nitro‐x‐pyridinecarboxylic acids (X = 3 and 5), 2‐chloro‐ and 2‐nitro‐4‐pyridinecarboxylic acids, and 4‐pyridinecarboxylic acid are reported. The 2‐pyridinecarboxylic acids lost carbon dioxide (M‐44) as has been reported. The 3‐pyridinecarboxylic acids showed no definite trend in fragmentation; however, the 4‐pyridinecarboxylic acids lost OH (M‐17) first. This change in fragmentation pat‐tern is due to an interaction of the ring nitrogen and carboxyl group in the 2‐pyridinecarboxylic acids which is not present in the 4‐pyridinecarboxylic acids.
Mass spectra of bithiophthalide and related compounds
Authors: Koch Charks W. , Markgraf I. Hodge 
Published: March 2009

AbstractHigh resolution mass spectra of biphlhalidu (1), bithiophthalide (2), and thioindigo (3) were investigated and the major fragmentation patterns were elucidated. The simultaneous loss of two sulfur atoms from the molecular ion of 2 was particularly noteworthy.
1,2,3,5‐Tetrahydro‐4H‐1,5‐benzodiazepin‐4‐ones and 1,2,3,4‐tetrahydro‐5H‐1,4‐benzodiazepin‐5‐ones from the reaction of hydrazoic acid on 1,2,3,4‐tetrahydroquinolin‐4‐ones
Authors: Misiti D. , Gatta F. , Landi‐Vittory R. 
Published: March 2009

AbstractThe Schmidt reaction on 1,2,3,4‐telrahydroquinolin‐4‐ones (1) gave 1,2,3,5‐telrahydro‐l,5‐benzodiazepin‐4‐ones (II) and 1,2,3,4‐tetrahydro‐1,4‐benzodiazepin‐5)‐ones(III). The ratio of II and III is dependent upon substituents present on the nitrogen ring atom of the quinolinones.
Preparation of 3,4‐dihydro‐2H‐1,3‐benzoxazines
Authors: Gaines Jack R. , Swanson Alan W. 
Published: March 2009

AbstractN,N‐Di(butoxymethyl)alkylamines react with phenols under mild conditions to yield substituted 3,4‐dihydro‐2H‐l,3‐benzoxazines.
Azetidinyl ketones. Synthesis of 1‐Alkyl‐2,4‐diphenyl‐3‐benzoylazetidines
Authors: Stevens Michael Fred , Cromwell Norman H. 
Published: March 2009

Abstractα‐(α'‐Bromobenzyl)chalcone (3) reacts with primary amines (t‐butyl, isopropyl,cyclohexyl) to give α‐(α'‐alkylaminobenzyl)chalcones (4, 5 and 6). When these allylic amines are treated with hydrogen bromide followed by reaction with base, they produce l‐alkyl‐2,4‐diphenyl‐3‐benzoyl‐azetidines (7,8 and 9). These azetidines were readily converted to their 3‐deuterio derivatives (10, 11 and 12) by treatment with sodium methoxide in deuteriomethanol. The configurations were assigned primarily by pmr spectra and mass spectra in reference to analogous compounds.
Reactions of 4‐dicyanomethylenepyrans with hindered primary amines
Authors: Vanallan J. A. , Reynolds G. A. 
Published: March 2009

AbstractThe reaction of 2,6‐dimethyl‐ and 2,6‐diphenyl‐4‐dicyanomethylene‐4H‐pyran with hindered primary amines such as isopropylamine and cyclohexylamine gave 1‐alkyl‐2‐amino‐3‐cyano‐6‐rnethyl(or phenyl)‐4‐acetonylidene (or phenacylidene)‐1,4‐dihydropyridine derivatives. The 6‐methyl‐4‐acetonylidene examples underwent a facile thermal rearrangement to give 1‐alkyl‐2,6‐dimethyl‐4‐dicy anomethy lene‐1,4‐dihydropy ridines. Several reactions of the acylidene derivatives are described.
Reactions of aziridines. Preparation and properties of 2‐thiazolinium salts
Authors: Westland Roger D. , Lin May H. , Vandenbelt J. M. 
Published: March 2009

AbstractReaction of 1‐substituted aziridines with thioamides in the presence of perchloric acid has provided a facile route to 2‐thiazolinium salts. Thioformamide was used in this reaction to give the 2‐unsubstituted 2‐thiazolinium salts 3‐[4‐(2,6‐xylyloxy)butyl]‐2‐thiazolinium perchlorate (11a) and 3‐(2‐cyelohexylbutyl)‐2‐thiazolinium perchlorate (IIc). A study of the rates of hydro‐lytic breakdown of IIc and 3‐(2‐cyelohexylbutyl)‐2‐methyl‐2‐thiazolinium perchlorate (IId) showed that the 2‐unsubstituted compound (IIc) was considerably less stable than the 2‐methyl analog (IId) over the entire pH range. Use of 1‐substituted aziridines in ring‐opening reactions, previously applied only to 1‐unsubstituted aziridines, has given expected products when thio‐cyanate ion or thiourea was the nucleophile.
The synthesis of 1,2,5‐thiadiazolo[3,4‐d] pyridazines
Authors: Pichler Don , Castle Raymond N. 
Published: March 2009

AbstractA number of previously unreported 1,2,5‐thiadiazolo[3,4‐d]pyridazines in this relatively unexplored ring system have been reported, charaeterized and screened for antibacterial and antifungal activity.
Studies on the syntheses of azole derivatives. Part VII. Syntheses of 1 ‐phenyl‐Δ2‐1,2,4‐triazolin‐5‐one derivatives [studies on the syntheses of heteroeyclic compounds. CD XI]
Authors: Kamatani Tetsuji , Shibuya Shiroshi , Shio Mamhisa 
Published: March 2009

AbstractBromination of 3‐methyl‐1‐phenyl‐Δ2‐1,2,3‐lriazolin‐5‐one (II) and its 4‐phenyl derivative III afforded the corresponding I‐(p‐Bromophenyl) derivatives IV and V, respectively. (Chlorination of the 4‐phenyl derivative III gave I‐(P‐chlorophenyl) derivative VI. In addition, 3‐N‐subsuituted‐carhamoyl‐1,2,4‐triazolin‐5‐ones(XII, XIII, and XIV) were synthesized by the Schotten‐Baumann reaction of 3‐carboxy‐1‐phenyl‐Δ2‐1,2,4‐triazolin‐5‐one (XI) with various amines.
Carbenes in sulfur and nitrogen heterocycles: A π‐electron‐scf‐mo study
Authors: Sorensen Herbert C. , Ingraham Lloyd L. 
Published: March 2009

AbstractThe properties of a lone pair carbon orbital have been assessed in the context of self consistent field molecular orbital theory. An improved parameter for sulfur is presented as well as a derivation of “carbene” type parameters. The relative effects of adjacent nitrogen and/or sulfur on a carbene have been predicted and compared to experiment. Special reference has been made to the biological systems of thiamine and anhydroleucovorin.