bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mass spectrometric fragmentation of some lignans
Authors: Duffield A. M. 
Published: March 2009

AbstractMass spectra of some lignans containing either γ‐butyrolactone, 1,2,3,4‐tetrahydro‐naphthalene or the 3,7‐dioxabicyclo[3. 3. 0]octane ring systems are reported. Probable structures are presented for the more abundant ions in the mass spectra of these lignans.
Irreversible enzyme inhibitors. LXXXI. Further observations on the mode of binding of the anilino moiety of 2‐amino‐5‐(anilinopropyl)‐6‐methyl‐4‐pyrimidinol to dihydrofolic reductase and thymidylate synthetase
Authors: Baker B. R. , Novotny Jaroslav 
Published: March 2009

AbstractReplacement of phenyl group of 2‐amino‐5‐(anilinopropyl)‐6‐methyl‐4‐pyrimidinol (III) by benzyl (XI) led to a large loss in binding to both dihydrofolic reductase and thymidylate synthetase; the binding by XI returned when the protonated benzylamino group was N‐acetylated to XII, which removes the charge at pH 7.4 and changes the ground‐state conformation of the benzene ring. Replacement of the benzyl group of the acetamide, XII, with the polar 2‐, 3‐, or 4‐, picolyl groups also led to a loss in binding. Substitution of p‐fluoro or m‐trifluoromethyl on the anilino group of III, or replacement of the anilino of III by 3‐pyridylamino, gave little ‐ if any ‐ enhancement in binding to the enzymes.
Pyrimidines. XIX. Pyrimido[4,5‐e]dihydro‐1,3‐oxazines and related compounds
Authors: O'Brien Darrell E. , Weinstock Louis T. , Springer Robert H. , Cheng C. C. 
Published: March 2009

AbstractA number of 2‐substituted 4,5‐dihydroxy‐6‐(substituted aminomethyl)pyrimidines (VIII) were prepared from the corresponding 2‐substituted 4,5‐dihydroxypyrimidines (VII) by a new pyrimidine Mannich reaction. The structure of VIII was proved by an independent synthesis. Further study of this reaction led to the synthesis of a new class of compounds: the pyrimido[4,5‐e]dihydro‐1,3‐oxazines (VI).
Benzologs of the thiazolo[3,2‐a]pyridinium system
Authors: Bradsher C. K. , Lohr D. F. 
Published: March 2009

AbstractBy use of concentrated sulfuric acid rather than hydrobromic acid as the cyclizing medium, good yields of the thiazolo[3,2‐a]quinolinium ion and its derivatives may be obtained from α‐(2‐quinolylthio) ketones or acetals. In the same way, α‐(1‐isoquinolylthio) and α‐(6‐phenanthridylthio) ketones afford thiazolo[2,3‐a]isoquinolinium and thiazolo‐[3,2‐f]phenanthridinium salts.
The chemistry of pyrazine and its derivatives. XII. The reaction of acetonylpyrazine with phenyllithium in the presence and absence of methyl benzoate
Authors: Chakrabartty Sujit K. , Levine Robert 
Published: March 2009

AbstractThe reaction of acetonylpyrazine with phenyllithium in the absence and presence of methyl benzoate gives (a) 2‐phenyl‐6‐acetonylpyrazine (IV) and (b) a mixture of IV and 3‐(2‐phenyl‐6‐pyrazyl)‐4‐phenylbutane‐2, 4‐dione (V, VI), respectively. Evidence in support of the structures of the products has been presented and comments on their formation are made.
Photochromism in the arylaroylaziridine system
Authors: Padwa Albert , Hamilton Lewis 
Published: March 2009

AbstractPhotochromism of a number of arylaroylaziridines has been observed in the solid state or in the rigid matrix. The photochromic behavior is dependent on the intensity of the incident radiation, the reaction medium, the wavelength of light used and on the relationship of the substituents on the three‐membered ring. From the visible absorption spectra it is clear that cis‐arylaroylaziridines give different colored species than do the trans isomers. These results suggest that the coloration is due to an extensive electrical interaction between the bent bonds of the aziridine ring and the π orbitals of the benzoyl and phenyl groups. Attempts to trap the colored species by co‐irradiation with substrates containing a multiple bond failed. A reaction has been found to occur upon heating various arylaroylaziridines with dimethylacetylene dicarboxylate in inert solvents.
1‐(Aziridine) carbonyl chlorides and 1‐(aziridine) carbonyl quaternary ammonium chlorides. Rearrangement to 2‐(chloroalkyl) isocyanates
Authors: Tomalia Donald A. , Paige Janet N. 
Published: March 2009

AbstractAziridine reacted with phosgene in the presence of an acid acceptor or with 1,1′‐carbonylbis(pyridinium) chloride to produce 1‐(aziridine)carbonyl chloride (XII) or 1‐(aziridine)carbonyl pyridinium chloride (XIII), respectively, as transient intermediates. Attempts to trap and observe (XII) and (XIII) at ‐10° were unsuccessful. These elusive materials underwent facile rearrangements to 2 ‐ chloroethyl isocyanate under these conditions. Aziridine reacted with 1,1′‐carbonylbis(triethylammonium)chloride (VII) at ‐20° to give 1‐(aziridine) carbonyl triethylammonium chloride (X) as a transient intermediate which proceeded to 2‐chloroethyl isocyanate. At ‐10° this reaction produced N,N‐diethyl‐1‐aziridinecarboxamide. Aziridine reacted with a large excess of phosgene in the absence of an acid acceptor to give N‐2‐(chloroethyl) carbamoyl chloride (III), 1,1′‐bis(2‐chloroethyl) urea (IV) and 2‐(β‐chloroethylamino)‐2‐oxazoline hydrochloride (V). Possible mechanisms for these reactions are discussed.
Irreversible enzyme inhibitors. XC. candidate active‐site‐directed irreversible inhibitors of thymidylate synthetase. I. 2‐amino‐5‐(benzenesulfonamidopropyl)‐6‐methyl‐4‐pyrimidinol with substituents on the benzene ring
Authors: Baker B. R. , Coward James K. 
Published: March 2009

Abstract2‐Amino‐5‐[p‐ (bromoacetamidomethyl)benzenesulfonamidopropyl]‐6‐methyl‐4‐pyrimidinol (XV) was synthesized by acylation of 2‐amino‐5‐aminopropyl‐6‐methyl‐4‐pyrimidinol (III) with p‐cyanobenzenesulfonyl chloride followed by catalytic reduction and reaction of the resultant aminomethyl group with p‐nitrophenyl bromoacetate. A second irreversible inhibitor of thymidylate synthetase, namely 2‐amino‐5‐[p‐(bromoacetyl)benzene‐sulfonamidopropyl]‐6‐methyl‐4‐pyrimidinol (XVI), was synthesized by acylation of in with p‐acetylbenzenesulfonyl chloride followed by bromination. Both XV and XVI were good reversible inhibitors of thymidylate synthetase and inactivated the enzyme when the candidate compound was incubated with the enzyme. Iodoacetamide, which does not form a complex with enzyme, could inactivate thymidylate synthetase almost as well as XV; therefore it appears that XV inactivated the enzyme by a random bimolecular mechanism rather than by the desired active‐site‐directed mechanism via an enzyme‐inhibitor complex. Similar conclusions were reached with XVI since phenacyl bromide could inactivate the enzyme somewhat more rapidly than XVI.
The synthesis of 5‐ and 6‐hydroxy‐2‐methylisoquinuclidine
Authors: Degraw Joseph I. , Kennedy Jill G. 
Published: March 2009

AbstractThe reduction of the isomeric 5,6‐epoxy‐2‐carboethoxyisoquinuclidines with lithium aluminum hydride afforded 5‐ and 6‐hydroxy‐2‐methylisoquinuclidine. Contrary to expectation essentially single epimers were obtained for each alcohol.
Synthesis of certain tricyclic quinoline derivatives as potential antiamebal agents
Authors: Cannon Joseph G. , Lazaris Spyros A. , Wunderlich Thomas A. 
Published: March 2009

AbstractSynthesis of the fused tricyclic systems, 1, 2, 3, 3a, 4, 5‐hexahydropyrrolo[1, 2a]quinoline (I) and 2, 3, 4, 4a, 5, 6‐hexahydro 1H‐benzo[c]quinolizine (II), each bearing an ethoxyl substituent on the benzene ring, has been achieved. The compounds combine certain structural features of the alkaloid emetine and of 8‐quinolinols.
The skraup syntheses and NMR spectra of some methylnaphthyridines
Authors: Paudler William W. , Kress Thomas J. 
Published: March 2009

AbstractSome mono‐ and dimethylnaphthyridines were prepared by the application of the Skraup reaction to various 2‐ and 4‐aminopyridines. The proton magnetic resonance spectral data assignments are reported. The chemical shifts of the methyl protons are calculated.
Structure of the reaction product of chloral hydrate and isocyanic acid
Authors: Loev Bernard , Dudek Gerald 
Published: March 2009

AbstractIn a recent article describing the reactions of isocyanic acid with carbonyl compounds, Hoover, Stevenson, and Rothrock (1) observed that chloral reacted slowly with free isocyanic acid at 0° to give CCl3CH(OH)NCO, m.p. 25°. On stirring with water, this was converted to a solid, m.p. 190‐200°, assigned structure A. This latter substance was also produced by reaction of isocyanic acid directly with chloral hydrate.
The preparation and rearrangement of 2‐allylbenzimidazole
Authors: Raines Stephen , Kovacs Csaba A. 
Published: March 2009

AbstractThis paper reports the preparation of 2‐allylbenzimidazole (I) and the facile migration of its double bond to the known isomeric 2‐propenylbenzimidazole (II). The proposed mechanisms of reactions of this type, involving a prototropic rearrangement, have been thoroughly discussed (1,2).
Cyclic sulfoxides. I. dihydrothiophene 1‐oxides
Authors: Krug Robert C. , Boswell Donald E. 
Published: March 2009

AbstractAlthough there have been extensive investigations on cyclic sulfones, especially the unsaturated, 5‐membered ring compounds (3), cyclic sulfoxides have received considerably less attention. In this report, we wish to present a synthesis of the previously unknown dihydrothiophene 1‐oxide isomers and, also, some preliminary results regarding their chemical reactivity (4).
Quinazolines and 1,4‐benzodiazepines XXXVI . The formation of 1,3‐dihydro and 1,5‐dihydro‐1,4‐benzodiazepines from tosyl and Mesyl ‐ substituted 1,3,4,5‐tetrahydro‐5‐phenyl‐ 1,4‐benzodiazepine derivatives
Authors: Ian Fryer R. , Winter D. , Stcrnbach L. H. 
Published: March 2009

AbstractThe treatment of 4‐sulfonyl derivatives of 5‐phenyl‐1,3,4,5‐tetrahydro‐1,4‐benzodiazepin‐2‐ones (I) with base was shown to result in the formation of 1,3‐dihydro or 1,5‐dihydro‐1,4‐benzodiazepin‐2‐ones (III and II respectively) depending upon the conditions used. The base treatment of 1‐sulfonyl substituted 2,3‐dihydro‐1,4‐benzodiazepines (V) was shown to give the vinylimines VI.
Chlorination of isothiocyanates. V . 5‐imino‐1,2,4‐thiadiazolidin‐3‐ones
Authors: Ottmann Gerhard , Hooks Haywood 
Published: March 2009

AbstractS‐[N'‐ (Chlorocarbonyl)amino]isothiocarbamoyl chlorides (II), obtained from S‐chloroisothiocarbamoyl chlorides (I) and isocyanates, react with primary aliphatic and aromatic amines to form the unknown class of 5‐imino‐1,2,4‐thiadiazolidin‐3‐ones. The structures were confirmed by chemical means and by spectroscopic methods.
Organosilicon compounds III. Silicon‐substituted thiophene derivatives of mercaptoethylamine as possible radioprotective agents
Authors: Thames Shelby F. , Mccleskey Josef E. 
Published: March 2009

AbstractThe preparation of the first organosilicon containing derivatives of mercaptoethylamine as possible radioprotective agents is described. The synthesis of these compounds via the thiazolidine intermediate was chosen due to the known radioprotective action of certain thiazolidines. We have prepared seventeen previously unreported organosilicon derivatives of which eleven contain the thiazolidine moiety and six are derivatives of mercaptoethylamine. The ability of these derivatives to protect against ionizing radiation will be determined.
New synthesis routes to 2‐halopyridines. II. 2‐bromopyridine
Authors: Boudakian Max M. , Gavin David F. , Polak Roger J. 
Published: March 2009

AbstractThe use of bromine chloride (equilibrium mixture) in substitution reactions has been extended to heterocyclic substrates. The vapor phase bromination of pyridine (I) with bromine chloride at temperatures as low as 375° (carbon tetrachloride diluent) gave the following product distribution: 2‐bromopyridine (IV) (75%) > 2‐chloropyridine (VI) (21%) > 3‐bromopyridine (II) (2.0%) ≅ 2,6‐dibromopyridine (VI) (1.5%). In contrast, when bromine was employed in place of bromine chloride (450°; carbon tetrachloride diluent), product orientation was significantly altered to give nearly equal quantities of 3‐bromopyridine (II) (17%) and 2‐bromopyridine (IV) (22.7%).
Pyrolysis of fluorodiazirines
Authors: Mitsch Ronald A. , Neuvar Erwin W. , Ogden Paul H. 
Published: March 2009

AbstractThe thermal decomposition of difluorodiazirine and difluoraminofluorodiazirine results in the formation of difluorocarbene and difluoraminofluorocarbene, respectively. The isolable products of the pyrolyses include fluoro‐alkenes, ‐cyclopropanes, ‐azines, ‐aziridines and in some cases isomerization products thereof.
Synthesis of substituted pyridazino[4,5‐c]pyridazines
Authors: Singerman Gary M. , Castle Raymond N. 
Published: March 2009

AbstractSeveral pyridazino[4,5‐c]pyridazines substituted in the 5‐ and 8‐positions with hydroxyl, mercapto and amino groups and in the 3‐position with a methyl group or a hydrogen atom have been prepared. In the course of this work five previously unreported pyridazine derivatives have also been synthesized.
Base catalyzed acylative decarboxylation. Part III. Acylation of homophthalic acid
Authors: Smith Grant Gill , Delong Carol Witte , Wetzel William H. , Muralidharan V. P. 
Published: March 2009

AbstractHomophthalic acid (I) reacts with acetic anhydride in the presence of base to form the expected product, o‐carboxyphenylacetone (III). Besides III, three other new products were formed, namely, 3‐methyl‐4‐carboxyisocoumarin (II), 4‐acetyl‐3‐methylisocoumarin (IV) and 8‐acetyl‐7‐methylnaphtho[1,2‐c]isocoumarin. A mechanism for the formation of these compounds is presented. The presence of 3‐methyl‐4‐carboxyisocoumarin (II) supports an earlier suggestion (1) that acylation can occur prior to and without decarboxylation, which has been a point of concern in this reaction.
Irreversible enzyme inhibitors. CXI. Candidate active‐site‐directed irreversible inhibitors of dihydrofolic reductase derived from 4,6‐diamino‐1,2‐dihydro‐l‐phenyl‐s‐triazines. V.
Authors: Baker B. R. , Johnson Morris A. 
Published: March 2009

AbstractCondensation of 5‐(p‐nitrophenyl)‐2‐pentanone with phenylbiguanide hydrochloride (V) gave a 2‐methyl‐2‐(p‐nitrophenylpropyl)‐1,2‐dihydro‐s‐triazine (IX); hydrogenation of the nitro group to amino followed by bromoacetylation afforded the candidate irreversible inhibitor of dihydrofolic reductase, namely, 2‐(p‐bromoacetamidophenylpropyl)‐4,6‐diamino‐1,2‐dihydro‐2‐methyl‐s‐triazine hydrochloride (VIII). Similarly, the o, m, and p‐isomers of 5‐nitrophenoxy‐2‐pentanone were converted to the corresponding 2‐(bromoacetamidophenoxypropyl)‐1,2‐dihydro‐s‐triazines (XI). The four candidate irreversible inhibitors were evaluated on the dihydrofolic reductases from pigeon liver, Walker‐256 rat tumor, and L‐1210/FR8 mouse leukemia. Only VIII was an irreversible inhibitor; VIII slowly inactivated the L‐121‐/FR8 mouse leukemia enzyme with a half‐life of 2–3 hours at 37°, but VIII showed no inactivation of the other two dihydrofolic reductases—a species specific inactivation.
Chlorination of isothiocyanates. VIII. Reaction of S‐chloroisothiocarbamoyl chlorides with aliphatic and cycloaliphatic ketones
Authors: Ottmann G. , Vickers G. D. , Hooks H. 
Published: March 2009

AbstractReported is the synthesis of various derivatives of 2‐imino‐5‐chloro‐1,3‐oxathiolanes, 2‐imino‐1,3‐oxathioles and 1,3‐thiazolin‐2‐ones from N‐aryl‐ and N‐alkyl‐S‐chloroisothiocarbamoyl chlorides and ketones.
The synthesis of imidazo[4,5‐c] ‐ and v‐triazolo[4,5‐c] pyridazines
Authors: Murakami Hirotaka , Castle Raymond N. 
Published: March 2009

AbstractThe parent imidazo[4,5‐c]pyridazine (IV) has been prepared for the first time by three different routes. 1‐Methylimidazo[4,5‐c]pyridazine (XX) and 3‐methylimidazo[4,5‐c]pyridazine (XXVII) have been prepared by unequivocal syntheses. The constitution of the methylation product of imidazo[4,5‐c]pyridazine‐2‐thiol (VIII) has been shown to be 2‐methylthioimidazo[4,5‐c]‐pyridazine (IX) by the unequivocal syntheses of 1‐methylimidazo[4,5‐c]pyridazine‐2‐thiol (XXIII) and 3‐methylimidazo[4,5‐c]pyridazine‐2‐thiol (XXXIII). Likewise, the structure of the methylation product (XIII) was shown to be S‐methylation by the unequivocal syntheses of 1‐methyl‐2‐methylthio‐6‐chloroimidazo[4,5‐c]pyridazine (XXIV) and 3‐methyl‐2‐methylthio‐6‐chloroimidazo[4,5‐c]pyridazine (XXXI), respectively. Several 7‐substituted amino‐v‐triazolo‐[4,5‐c]pyridazines (XXXVIII) have been prepared from 7‐chloro‐v‐triazolo[4,5‐c]pyridazine (XXXVII).
4‐Thiazoline‐2‐thiones. IV. Preparation from amino acids
Authors: Lamon R. W. , Humphlett W. J. 
Published: March 2009

Abstract4‐Thiazoline‐2‐thiones derived from amino acids have been obtained by an improved procedure. Depending on substitution, the type of intermediate product isolated may be a 4‐hydroxythiazolidine‐2‐thione or a dithiocarbamate.
The reaction of benzotriazoles with 3,4‐dihydro‐4H‐pyrane and 2‐acetoxymethyl‐3,4‐dihydro‐2H‐pyrane
Authors: García‐Muñoz G. , Iglesias J. , Lora‐Tamayo M. , Madroñero R. , Stud M. 
Published: March 2009

AbstractFrom the reaction of benzotriazoles with 2,3‐dihydro‐4H‐pyrane and 2‐acetoxymethyl‐3,4‐dihydro‐2H‐pyrane the corresponding 1‐(2‐tetrahydropyranyl)benzotriazole and cis‐and trans‐1‐(6‐acetoxymethyl‐2‐tetrahydropyranyl)benzotriazole derivatives were obtained. The structures and conformations of these compounds were confirmed by UV and NMR spectra.
Diazepines. V. The reaction of homophthalic anhydride with hydrazines
Authors: Rosen Gerald , Popp Frank D. 
Published: March 2009

AbstractThe reaction of homophthalic anhydride with hydrazine and a number of substituted hydrazines has been investigated. Only in the case of the reaction of homophthalic anhydride and 1,2‐dimethylhydrazine has a diazepine been isolated. The previously reported (2) diazepine from homophthalic anhydride and hydrazine appears to be a product resulting from the reaction of twomolec of homophthalic anhydride with one mole of hydrazine.
Acylation of purine‐8‐thione and benzimidazole‐2‐thione: A reinvestigation of the site of acylation
Authors: Dyer Elizabeth , Minnier Carl E. 
Published: March 2009

AbstractPurine‐8‐thione (1) is acylated on nitrogen, not on sulfur as was previously reported. Thus, the reactions of 1 with ethyl chloroformate and with acetic anhydride yield, respectively, ethyl purine‐8‐thione‐9(7)‐carboxylate (3) and 9(7)acetylpurine‐8‐thione (7) as shown by independent synthesis and spectra. In like manner, benzimidazole‐2‐thione (10) reacts with acetic anhydride, ethyl chloroformate, benzoyl chloride, and cyclohexyl isocyanate to yield the corresponding N‐acylated derivatives. In addition, 10yields 1,3‐dibenzoylbenzimidazole‐2‐thione on treatment with 2 equivalents of benzoyl chloride.
The reactions of 2,2‐difluoro‐4‐methylnaphtho[l,2‐e] ‐1,3,2‐dioxaborin and Its [2,1‐e] Isomer with Carbonyl compounds and with Aniline
Authors: Vanallan J. A. , Reynolds G. A. 
Published: March 2009

Abstract2,2‐Difluoro‐4‐methylnaphtho[l,2‐e]‐l,3,2‐dioxaborin (1) and its [2,1‐e]isomer (2) react with equimolecular quantities of carbonyl compounds, giving colored ethylenic derivatives. With aniline, 1 and 2 give the corresponding oxazaborins 21 and 22. The structures of 1 and 2 are discussed.
Syntheses of benzomorphan and related compounds. Part 1. Synthesis ofN‐substituted‐l,2,3,4,5,6‐hexahydro‐8‐hydroxy‐2,6‐methano‐6,11‐dimethyl‐3‐benzazocine [studies on the syntheses of heterocyclic compounds. Part CCLXXXII ]
Authors: Kametani T. , Kigasawa K. , Hüragi M. , Hayasaka T. , Wagatsuma N. , Wakisaka K. 
Published: March 2009

AbstractA modified synthesis of pentazocine, l,2,3,4,5,6‐hexahydro‐8‐hydroxy‐2,6‐methano‐6, H‐dimethyl‐3‐(3‐methyl‐2‐butenyl)‐3‐benzazocine (III), has been achieved and catalytic hydro‐genation has been found to be effective for the debenzylation of quaternary ammonium salts.
Ochotensine and related compounds. II. A synthesis of iso‐ochotensine. (Studies on the syntheses of heterocyclic compounds. CCLXXV )
Authors: Kametani T. , Takano S. , Hibino S. , Terui T. 
Published: March 2009

AbstractIn order to examine the total syntheses of ochotensine (1) and ochotensimine (II), one of the isomers, iso‐ochotensine (III), was synthesized as a preliminary experiment. Namely, Wittig reaction of VI, followed by treatment with sodium bicarbonate solution, gave the expected compound, 7‐ethoxycarbonyl‐3‐ethoxycarbonyloxy‐2‐methoxy‐13‐methyIene‐10,11‐methyIene‐dioxyochotensinan (VII) which was reduced with lithium aluminum hydride to give III. This was also obtained by methylation of 3‐hydroxy‐2‐methoxy‐13‐methylene‐10,11‐methyIenedioxy‐ochotensinan (VIII).
Chemistry of thienopyridines. VI. Reaction of hydrogen sulfide with pyridines bearing C2‐groups in the 3‐position
Authors: Klemm L. H. , Mccoy D. R. 
Published: March 2009

Abstract3‐Substituted pyridines (bearing vinyl, ethyl, α‐hydroxyethyl, and acetyl substituents) react with hydrogen sulfide at 630° to give low yields of thieno[2,3‐b]pyridine and thieno[3,2‐c]‐pyridine. For 3‐vinylpyridine as substrate, it is proposed that a free‐radical process is involved in this synthesis.
Enamine formation from anilines and methyl propiolate. The synthesis of 4(1h)‐quinolones
Authors: Heindel Ned D. , Kennewell Peter D. , Fish Velmer B. 
Published: March 2009

AbstractThe addition of substituted anilines to methyl propiolate produces labile cis‐trans mixtures of enamines which can be isomerized by acid, solvent variation, and thermal techniques. Thermal cyclization of these enamines provides a synthesis of 4( lH)‐quinolones.
The synthesis of lmidazo[4,5‐d] pyridazines. VI. v‐Triazolo[4,5‐d] pyridazines, pyrazino[ 2,3‐d ] pyridazines and 7H‐Imidazo [4,5‐d] tetrazolo[ 1,5‐b] pyridazine
Authors: Martin Stephen F. , Castle Raymond N. 
Published: March 2009

AbstractSeveral pyridazines have been prepared as intermediates in the synthesis of monosubstituted imidazo[4,5‐d]pyridazines, monosubstituted v‐triazoIo[4,5‐d]pyridazines and monosubstituted pyrazino [2,3d] pyridazines. The new ring system, 7H‐imidazo[4,5‐d]tetrazolo[l,5‐b] pyridazine (XIV) has been prepared unsubstituted. Furthermore, unsubstituted imidazo[4,5‐d]pyridazine (XI) has been prepared. Calculations for XI and XIV were made by approximate SCF LCAO‐MO with CNSO II theory.
2‐Aminothiophene. Heterocyclization of benzylthionitriles
Authors: Eck David L. , Stacy Gardner W. 
Published: March 2009

AbstractSynthesis of unstable 2‐aminothiophene by way of its hydrochloride salt has been achieved in excellent yield. The key reaction in the scheme involves a novel heterocyclization of benzylthionitriles, which would appear to have general utility. Spectral and physical properties are tabulated and a possible mechanism is proposed.
Azetidinyl ketone chemistry. C‐Methylation reactions and stereostructure ‐ spectra relationships
Authors: Doomes Earl , Cromwell Norman H. 
Published: March 2009

AbstractThe C‐methylation of the potassium salt of 1‐t‐butyl‐2‐phenyl‐3‐(p‐phenylbenzoyl)azetidine (1a) with methyl iodide was studied in three solvents, and the stereochemical outcome of the reaction was shown to be dependent upon the solvent used. These results are rationalized in terms of the probable relative rates of the reaction in the various solvents and/or the effect of solvent on the structure of the anionic intermediate. Similar treatment of the potassium salt of 1‐t‐butyl‐2‐phenyl‐3‐benzoylazetidine (3a) in ethyl ether gave a comparable result. The configurations of the epimeric C‐methyl products (2a and 2b, and 4a) were assigned on the basis of their spectral properties. With the aid of spectral data for a model compound, l‐t‐butyl‐3‐benzoyl‐azetidine (5), several stereostructure‐spectra relationships for 3‐azetidinyl ketones are presented.
Synthesis of substituted 2‐amino‐3‐cyanodihydrofurans from styrene oxides and malononitrile
Authors: Campaigne E. , Ellis R. L. , Bradford Mary 
Published: March 2009

AbstractThe reaction of styrene oxides with the malononitrile anion leads to the formation of 2‐amino‐3‐eyano‐5‐aryl‐4,5‐dihydrofurans (III), while a similar reaction with β,β‐dimethylstyrene oxides leads to 2‐amino‐3‐cyano‐4‐aryl‐5,5‐dimethyI‐4,5‐dihydrofurans (V). Therefore steric factors may play a significant role in the site of attack of the malononitrile anion on the oxide. Compounds of type V are more conveniently obtained from the cyanolaetones (VI) by rearrangement and dehydration.