bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new class of heterocyclic betaines: 1,1‐dimethyl‐3‐phenylpyrazolium‐5‐oxide
Authors: Henery‐Logan Kenneth R. , Keiter Ellen A. 
Published: March 2009

Abstract1,1‐Dimethyl‐3‐phenylpyrazolium‐5‐oxide (1) was isolated as a minor product (3%) in the reaction of ethyl benzoylacetate with 1,1‐dimethylhydrazine and also was obtained as the major product (58%) from the reaction of methyl p‐toluenesulfonate with ethyl benzoylacetate dimethylhydrazone. The structural assignment was made on the basis of chemical reactions and spectral data and the formula is represented by a resonance structure for which there are two principal canonical forms. Reaction of 1 with methanol at room temperature afforded methyl benzoylacetate dimethylhydrazone. Ethyl benzoylacetate dimethylhydrazone was shown to exist as a tautomeric mixture containing 65% of the imine form at room temperature.
The mass spectra of pseudo‐azulenes containing both nitrogen‐ and sulfur‐heteroatoms
Authors: Buu‐Hoï N. P. , Croisy A. , Jacquignon P. , Martani A. , Ricci A. 
Published: March 2009

AbstractThe fragmentation under electron impact of [1]benzothiopyrano[4,3‐b]indoles and their thiophene analogs has been investigated. These pseudo‐azulenes behaved in accordance with their aromatic structure and their fragmentation followed simple patterns, leading to hitherto unreported ions.
Benzothiazinones by addition of o‐Mercaptobenzamides to acetylene esters
Authors: Heindel Ned D. , Ko C. C. Ho 
Published: March 2009

AbstractThe condensation of o‐mercaptobenzamides with methyl acetylenedicarboxylate or methyl propiolate occurs with trans addition of the SH to the alkyne linkage. The resulting vinyl sulfide adducts can be ring closed to 1,3‐benzothiazin‐4‐ones in excellent yield.
Reaction of 4,5‐diaminopyrimidine and ethyl acetoacetate: Synthesis and chemistry of isomeric dihydropyrimido[4,5‐b][1,4] diazepinones
Authors: Israel Mervyn , Tinter S. Karin , Trites Dorothy H. , Modest Edward J. 
Published: March 2009

AbstractDepending upon reaction conditions, 4,5‐diaminopyrimidine and acetoacetic ester gave a variety of condensation products, including the two isomeric dihydropyrimido[4,5‐b][1,4]‐diazepinones. Under conditions leading to bicyclic products, the formation of 1,5‐dihydro‐4‐methyl‐2H‐pyrimido[4,5‐b][1,4]diazepin‐2‐one (2) was strongly favored. The isomeric 3,5‐dihydro‐2‐methyl‐4H‐4‐one compound (4) was best obtained by cyclization of ethyl 3‐(4‐amino‐5‐pyrimidylamino)crotonate (3) under base catalysis. Thermal rearrangement of 2 and 4 proceeded, in each instance, with loss of the isopropenyl moiety and gave 8‐purinone. Compound 4 underwent ring contraction under the influence of alkoxide to yield a product which was shown to be the 7‐isopropenyl‐8‐purinone (6).
Fluorinated aminooxazolines. Synthesis and properties
Authors: Middleton W. J. , Metzger Diana , Cunningham Karen B. , Krespan C. G. 
Published: March 2009

Abstract4‐Amino‐2,2,5,5‐tetrakis(trifluoromethyl)‐3‐oxazoline (3a) was prepared from the reaction of sodium cyanide with hexafluoroacetone and hexafluoroacetone imine, and from the reaction of hexafluoroacetone cyanohydrin with the imine. Several other oxazolines were also prepared by related reactions of other fluoroketones and imines. The proton nmr spectrum of an 15N‐labeled sample of 3a shows that it exists in solution primarily as the amino tautomer and not as the imino tautomer 3b. Comparison of 3a with the closely related, pharmacologically active 4‐amino‐2,2,5,5‐tetrakis(trifluoromethyl)‐3‐imidazoline (2) has shown large differences in ΔH of complex formation and reactivity with electrophilic reagents.
The reaction ofN‐Acylpyridinium salts with indole
Authors: Bergman Jan 
Published: March 2009

AbstractDepending on the solvent used and the ratio of the reactants,N‐acylpyridinium salts condense with indole to give 3‐(N‐acyl‐1,4‐dihydro‐4‐pyridyl)indole (1) or 4‐(N‐acyl‐3‐indolyl)pyridinium chloride (3). Compound 1 is an intermediate in the formation of compound3. The reaction mechanism has been studied, and a hydrogen transfer reaction is suggested as a key step. Alkaline hydrolysis,e.g., of 4‐(N‐acetyl‐3‐indolyl)pyridinium chloride (3a), gave 3‐(4‐pyridyl)indole (2a).The reaction of α‐chlorosubstituted acyl halides with indole, in the presence of pyridine constitutes a convenient synthesis of 3‐chloroacylindoles.
Circular dichroism spectra of 1,2,3,4,5,6‐Hexahydro‐2,6‐methano‐3‐benzazocines
Authors: Karliner J. , Yee E. 
Published: March 2009

AbstractCircular dichroism curves of levorotatory 1,2,3,4,5,6‐hexahydro‐2,6‐methano‐3‐benzazocin‐8‐ol derivatives have been determined and correlated with stereochemical features. Compounds with the rectus configuration at C‐6 were found to exhibit negative extrema for the long wavelength phenolic π → π* transition. The remaining Cotton effects have been ascribed to specific aromatic π → π* transitions.
Photostable o‐Hydroxyphenylquinazolines
Authors: Pater Richard 
Published: March 2009

AbstractThe correlation between intrinsic photostability (ϕ−1R) and structure of several intramolecularly hydrogen‐bonded heterocycles containing suitable o‐hydroxyphenyl groups is briefly discussed in terms of the changes in resonance energy resulting in such compounds from a reversible keto‐enol rearrangement in the lowest excited singlet state. The influence of intramolecular hydrogen bonding, resonance and steric effects on photostability in o‐hydroxyphenylquinazolines as elucidated with the aid of spectroscopic methods is discussed in detail.
7‐Amino‐5‐imino‐8(5H)‐quinolones, 6‐Amino‐8‐imino‐5(8H)‐quinolones and 7‐Alkyl‐4,6‐dihydroxy‐5,8‐quinolinediones as potential antiprotozoal agents
Authors: Bullock F. J. , Tweedie J. F. 
Published: March 2009

AbstractOxidation of 7‐amino‐8‐hydroxyquinoline‐5‐sulfonic acid with silver oxide in dimethylformamide and in the presence of arylamines provided a series of 7‐amino‐5‐arylimino‐8(5H)‐quinolones (VIIIb). Reaction of 8‐dialkylamino‐5,6‐quinolinediones with triethyloxonium tetrafluoborate gave a series of unstable but synthetically useful enol ethers. These reacted with amines to give 6‐amino‐8‐imino‐5(8H)‐quinolones, isolated and characterized as tetrafluoborate salts (XIa). Proton magnetic resonance studies showed these to be vinylogous amidinium salts, analogous to those previously obtained with 2‐amino‐1,4‐naphthoquinone imines. 4,6‐Dihydroxy‐5,8‐quinolinedione underwent free radical alkylation to give a 7‐alkyl‐4,6‐dihydroxy‐5,8‐quinolinedione. Evaluation of the new compounds against various Plasmodium species in rodents, birds and mosquitoes revealed no significant antimalarial activity.
Synthesis of pyridyl‐ and quinolyl‐substituted 2‐aminothiazoles
Authors: Taurins Alfred , Blaga Aurel 
Published: March 2009

AbstractFive 2‐amino‐4‐(x‐pyridyl)‐ and 2‐amino‐4‐(x‐quinolyl)thiazoles have been synthesized by the condensation of thiourea with bromoacetylpyridines and ‐quinolines. The reaction of pyridyl pyridylmethyl ketones with thiourea and halogens produced four 2‐aminothiazoles possessing pyridyl substituents in 4‐ and 5‐positions on the thiazole ring. Treatment of N‐(3‐pyridyl)‐ and N‐(3‐quinoiyl)thiourea with α‐bromoketones gave seven new 2‐(3‐pyridyl)amino‐ and 2‐(3‐quinolyl)aminothiazoles. The ultraviolet spectra of the pyridyl‐ and quinolyl‐ substituted 2‐aminothiazoles were recorded.
Oxidative coupling of 2H‐1,4‐Thiazine derivatives
Authors: Sica D. , Santacroce C. , Prota G. 
Published: March 2009

AbstractWhen treated with oxidizing agents, 3,5‐disubstituted 2H‐1,4‐thiazines undergo oxidative coupling at the 2‐position yielding 2,2′‐bithiazines. Under similar conditions 3‐substituted 2H‐1,4‐benzothiazines behave similarly to give the corresponding 2,2′‐dehydrodimers.Evidence is presented that the oxidative coupling of all compounds examined proceeds preferentially to give the meso‐isomers.
The synthesis and chemical reactivity of thieno[2,3‐c]‐ and thieno[3,2‐c] pyridines
Authors: Dressler Mitchell L. , Joullié Madeleine M. 
Published: March 2009

AbstractThe syntheses and reactions of various thieno[2,3‐c]‐ and thieno[3,2‐c] pyridines are described. Molecular orbital calculations were performed on thieno[2,3‐c]pyridine (1) in order to determine the most susceptible sites to electrophilic and nucleophilic attack. Superdelocalizability values, Sr‐ are reported for each position in this molecule to give relative orders of reactivity towards the two types of reactions. Electrophilic attack was found to occur experimentally at C‐3 in all the thienopyridines studied. Peracid oxidation of thieno[2,3‐c]‐ and thieno[3,2‐c]pyridines produced only the N‐oxide. The lack of reactivity of certain thienopyridines under Vilsmeier formylation and Friedel‐Crafts acetylation conditions was related to their basicities. The dissociation constants of various thienopyridinium salts are reported.
The synthesis of alkyl substituted 2‐pyrazolines by the reaction of acids with hydrazine derivatives
Authors: Sloan K. H. , Rabjohn Norman 
Published: March 2009

AbstractA convenient synthesis of alkyl substituted 2‐pyrazolines (III) has been developed from the reaction of acids with hydrazones (I) and azines (IV). An alkylidenebis‐1‐methyl‐2‐alkylidene‐hydrazine (V) was isolated as an intermediate, in the preparation of 5‐isopropyl‐1,4,4‐ trimethyl‐2‐pyrazoline (IIId), and protonated vinylhydrazones (II) are proposed as common intermediates in the formation of III, IV and V. The 4,5‐dialkyl‐2‐pyrazolines (IIIk‐m) that were prepared were shown to be free of isomers by nmr. The thermal isomerization of IIIk‐m to 3,4‐dialkyl‐2‐pyrazolines (IIIn‐o) was found to be incomplete at the temperatures studied. The reaction of IIIn‐o with acetone afforded 3,4‐dialkyl‐1‐[2‐(2‐methyl‐4‐oxopentyl)]‐2‐pyrazolines (IIIp‐q). The nmr and mass spectral data of III are discussed.
The reaction of aziridine with perhalogenated nitriles
Authors: Lautenschlaeger F. 
Published: March 2009

AbstractReaction of one or two molecules of aziridine with the cyano groups of trichloroacetonitrile and trifluoroacetonitrile was observed. The resulting aziridinyl amino derivatives represent novel functional groups. Intramolecular cyclization of a bis‐aziridinyl structure involving one aziridinyl group was observed. New synthetic routes to imidazolines and imidazolidines are a result of these rearrangments.
Synthesis of imidazo[1,2‐c] quinazoline and some of its methyl derivatives
Authors: Franchetti Palmarisa , Grifantini Mario 
Published: March 2009

AbstractThe synthesis of imidazo [1,2‐c] quinazoline was effected by manganese dioxide oxidation of the 5,6‐dihydroimidazo [1,2‐c] quinazoline which was prepared by treatment of 2‐(o‐nitro‐phenyl)‐1‐hydroxyimidazole‐3‐oxide with zinc powder and formic acid. The synthesis of some methyl derivatives of this ring system are also described. Structural assignments for all of the products were made from spectral data.
The synthesis of o‐Amino‐N‐substituted benzamides and 3‐substituted 2,4 (1H,3H)‐quinazolinediones from isatoic anhydride
Authors: Jacobs Richard L. 
Published: March 2009

AbstractThe reaction of isatoic anhydride with sterically hindered amines in DMF or DMSO, and subsequent treatment of the o‐amino‐N‐substituted benzamides thus produced with phosgene, gives high yields of 2,4(1H,3H)‐quinazolinediones with branched alkyl groups in the 3‐position.
1,4‐Cyeloaddition reactions. IV. preparation of Cyclopenta[g]furo[3,2‐c]quinolines, Cyclopenta‐ [f]furo[3,2‐c]quinolines, Benzo[H]furo[3,2‐c]quinolines, and Furo‐ [3,2‐c]indeno[1,7‐gh] quinolines from 2,3‐Dihydro‐5‐methylfuran and schiff bases
Authors: Worth Donald F. , Perricone S. C. , Elslager Edward F. 
Published: March 2009

AbstractThe boron trifluoride catalyzed 1,4‐addition of 2,3‐dihydro‐5‐methylfuran to N‐(p‐methoxybenzylidene)‐5‐indanamine (VI) gave 2 pairs of epimers, dl‐3,3a,4,5,7,8,9,10b‐octahydro‐4‐(p‐methoxyphenyl)‐10b‐methyl‐2H‐cyclopenta[g]furo[3,2‐c]quinoline (VIIa and b) and dl‐3,3a, 4,‐5,8,9,10,10c‐octahydro‐4‐(p‐methoxyphenyl)‐10c‐methyl‐2H‐cyclopenta[f]furo[3,2‐c]quinoline (VIIIa and b). When 4‐(benzylideneamino)‐1‐naphthol (IXa) was condensed with 2,3‐dihydro‐5‐methylfuran in an analogous manner, a mixture of two isomers of dl‐1,2,2a,3,4,5a‐hexahydro‐5a‐methyl‐2‐phenylbenzo[h]furo[3,2‐c]quinolin‐7‐ol [Xa and b (R  H)] was obtained. Likewise, 4‐[(p‐hydroxybenzylidene)amino]‐1‐naphthol (IXb) and 4‐(p‐methoxybenzylidene)amino]‐1‐naphthol (IXc) gave a mixture of two isomers of dl‐1,2,2a,3,4,5a‐hexahydro‐2‐(p‐hydroxyphenyl)‐5a‐methylbenzo[h]furo[3,2‐c]quinolin‐7‐ol [Xa and b (R  OH)] and dl‐1,2,2a,3,4,5a‐hexahydro‐2‐(p‐methoxyphenyl)‐5a‐methylbenzo [h]furo[3,2‐c]quinolin‐7‐ol [Xa and b (R  OCH3)], respectively. The condensation of N‐(p‐methoxybenzylidene)‐5‐acenaphthenamine (XI) with 2,3‐dihydro‐5‐methylfuran afforded a mixture of two isomers of dl‐2,3,3a,4,5,9,10,‐11b‐octahydro‐4‐(p‐methoxyphenyl)‐11b‐methylfuro[3,2‐c]indeno[1,7‐gh]quinoline (XIIa and b). Structural assignments for all of the products were made from NMR spectra. None of these compounds possessed appreciable biological activity.
Studies in organic mass spectrometry. III. Adenosine 8‐Cyclonucleosides
Authors: Ikeda Masazumi , Tamura Yasumitsu , Ikehara Morio 
Published: March 2009

AbstractThe mass spectra of purine 8‐cyclonucleosides have been determined and compared with those of purine nucleosides. The mass spectra of the former are characterized not only by the presence of an intense molecular ion but also by the presence of the peaks corresponding to 8‐oxy (or 8‐thio) adenine and its protonated form due to a double and triple hydrogen transfer.
The syntheses of pyridazino[1,2‐a] pyridazine derivatives of furan, pyridazine and pyrrole by diels‐alder reactions
Authors: Gillis Bernard T. , Valentour James C. 
Published: March 2009

AbstractDiels‐Alder adducts were formed in the lead tetraacetate oxidations of substituted cyclic hydrazides of furan, pyridazine and pyrrole dicarboxylic acids in the presence of 1,3‐cyclo‐hexadiene or 1,3‐cyclopentadiene. The products resulting were furo[3,4‐g]pyridazino[1,2‐a]‐pyridazine‐6,10‐diones, pyridazino[4,5‐g]pyridazino[1,2‐a]pyridazine‐6,11‐diones, and pyrrolo‐[3,4‐g]pyridazino[1,2‐a]pyridazine‐6,10‐diones, respectively. Some hydrogenations and ring opening reactions were studied.
2‐Carboazetidine derivatives
Authors: Rodebaugh Richard M. , Cromwell Norman H. 
Published: March 2009

AbstractA reaction sequence is reported for converting methyl 7‐bromocrotonate to 1‐alkyl‐2‐carbo‐methoxyazetidines thus confirming our earlier structural assignments of these compounds obtained by a more direct route. Methods are described for obtaining azetidinyl alcohols, acids, amides, amines and ketones. 1‐t‐Butyl‐2‐carbomethoxyazetidine was observed to undergo ring opening to an acyclic γ‐aminohydrazide derivative when treated with hydrazine hydrate. On the other hand, the corresponding N‐benzylazetidine under similar conditions rearranged to 1‐benzyl‐2‐pyrrolidinone.
Reaction of 4,5‐diaminopyrimidines with 2,5‐hexanedione
Authors: Youssefyeh R. D. , Kalmus A. 
Published: March 2009

AbstractReaction of 2,5‐hexanedione with various 4,5‐diaminopyrimidines was found to lead to the formation of 5‐(N‐pyrryl)‐4‐aminopyrimidines. Structural assignments for the products obtained were made on the basis of nmr, ir, uv and mass spectral data.
Perchloroimidazo[1,2‐a] pyridine. Synthesis and nucleophilic substitutions
Authors: Paudler William W. , Pokorny David J. , Good James J. 
Published: March 2009

AbstractPerehloroimidazo[1,2‐a]pyridine has been prepared and it has been shown that nucleophilic substitution occurs preferentially at C5 possibly followed by substition at C7.
Syntheses of some indazoles structurally related to equilenin
Authors: Morgan John G. , Berlin K. Darrell , Durham Norman N. , Chesnut Robert W. 
Published: March 2009

AbstractThis study reports the complete synthesis and characterization of the 15, 16‐diazaequilenin derivative 10,11‐dihydro‐3H‐naphth[1,2‐g]indazol‐7‐ol (2b) as well as the methyl ether 2a of the above compound and the novel “model” compound 4,5‐dihydro‐1H‐benz[g]indazol‐7‐ol (3b). Indazoles 2a and 3a have demonstrated in vitro activity against a variety of microorganisms.
Cyclization of ylidenemalononitriles. VII. Studies on sulfur‐containing heterocyclic systems
Authors: Campaigne E. , Burton H. R. , Blanton C. D. , Schneller S. W. 
Published: March 2009

AbstractRing closure of ylidenemalononitrile adducts has been extended to the syntheses of isomeric sulfur heterocycles. The malononitrile derivatives of thiochromanone, thiochromone and iso‐thiochromanone have been synthesized, and results of the acidic ring closure experiments on these compounds are reported. The thiochromanone adducts gave an interesting disproportionation reaction, and experiments designed to support the proposed route are presented.
Synthesis of 10‐deazapteroic and 11‐deazahomopteroic acids
Authors: Degraw Joseph I. , Tsakotellis Panayotis , Kisliuk Roy L. , Gaumont Yvette 
Published: March 2009

AbstractThe syntheses of 10‐deazapteroic and 11‐deazahomopteroic acids are described. These compounds along with their simple 6‐phenylalkylpteridinol relatives were found to be inactive as antimalarial agents against the Plasmodium berghei or Plasmodium gallinaceum strains. 10‐Deazapteroie acid was a potent growth inhibitor of Streptococcus faecium both in the pteridine and tetrahydropteridine forms.
Novel boron heterocycles. II. 2,3‐dihydro‐1,3,5,2‐oxadiazaboroles, 1,2‐dihydro‐1,3,2‐benzodiazaborine 3‐oxide, and 3,4‐dihydro‐2H‐1,2,4,3‐benzothiadiazaborine 1,1‐dioxide
Authors: Yale Harry L. 
Published: March 2009

AbstractA number of arylamidoximes, an o‐aminobenzaloxime, and an o‐aminobenzenesulfonamide have been reacted with boronic acids to give three novel boron containing heterocycles. Evidence, based on mass spectroscopy, that the product from o‐aminobenzaloxime is a 1,2‐dihydro‐l,3,2‐benzodiazaborine 3‐oxide, is presented.
Synthesis of 3‐ and 4‐(β‐D‐ribofuranosyl)‐s‐triazolo[2,3‐a] pyrimid‐7‐one, isomers of inosine containing a bridgehead nitrogen atom
Authors: Winkley Michael W. , Judd Gerard F. , Robins Roland K. 
Published: March 2009

AbstractThe first synthesis of a purine nucleoside analog containing a bridgehead nitrogen atom is here reported. The direct glycosylation of the trimethylsilyl derivative of s‐triazolo[2,3‐a] pyrimid‐7‐one has been shown to give 3‐(β‐D‐ribofuranosyl)‐s‐triazolo[2,3‐a]pyrimid‐7‐one (V) and 4‐(β‐D‐ribof'uranosyl)‐s‐lriazolo[2,3‐α]pyrimid‐7‐one (VII). The nueleoside V may he considered a close analog of inosine in which the nitrogen N1 and C5 of inosine have been interchanged. Bro‐minalion of the tri‐O‐acelyl derivative IV gave, after deblocking, 6‐bromo‐3‐(β‐D‐ribofurnaosyl)‐s‐triazolo[2,3‐a] pyrimid‐7‐one (IX). Structural assignments of the nucleosides were made on the basis of comparison of the ultraviolet absorption spectral characteristics with 3‐methyl‐s‐triazolo‐[2,3‐a]pyrimid‐7‐one (XI) and 4‐methyl‐s‐lriazolo[2,3‐a Jpyrimid‐7‐one (XII) prepared by a standard procedure from 7‐methoxy‐s‐triazolo(2,3‐a] pyrimidine (X).
Organosilicon compounds XIII. Cleavage of the silicon‐carbon bond of 2‐trimethylsilylbenzothiazole
Authors: Pinkerton Frank H. , Thames Shelby F. 
Published: March 2009

AbstractThe high‐yield synthesis of 2‐trimcthylsilylbenzothiazole is described, and the labile nature of this silicon‐helerocyclic bond is proved when cleavage is affected by aldehydes, acid halides, chloro‐formates and anhydrides. Justification for this unusual reactivity and further insight into the reaction mechanism is offered.
Heterocyclic N‐glycosides. VIII. Anomerisation and rearrangement of 2′,3′‐unsaturated N‐glycosides
Authors: Fucrtes M. , Garcíaa‐Muñtoz G. , Madroñtro R. , Stud M. 
Published: March 2009

AbstractThe acid catalyzed transformation of cither 1‐(4 ‐O‐acety1‐2,3 ‐dideoxy‐α‐ or β‐L‐glycero‐pent‐2 ‐cnosyl)‐5,6‐dichlorobenzotriazole gave the same mixture of unsaturuted glycosides. The main three components of this mixture were the above α and β anomers and a glycal‐type compound which results from the allylic rearrangement of the 5,6‐dichlorobenzotriuzole moiety to the C‐3 position of the carbohydrate. Evidence is presented that these results can be rationalized as proceeding through an allylic carbonium ion. Preliminary experiments on transglycosidation reactions using 2′,3′‐unsaturated N‐glycosides are reported.
Nuclcophilic substitution reactions of 5‐acetoxymethyl‐and 5‐p‐nitrophenoxymethyluraeils
Authors: Santi Daniel V. , Pogololti A. L. 
Published: March 2009

AbstractThe synthesis of a number of 5‐acetoxymethyl‐ and 5‐p‐nitrophenoxymethyluracils and their nucleophilic substitution reactions with sodium methoxide and sodium borohydride are reported. These reactions all appear to involve intermediates with carbonium ion character, the formation of which are dependent upon structural features of the heterocycle. Most facile reactions occur when the 1‐position of the heterocycle can accommodate a negative charge to assist in the formation of highly reactive 5‐methenyluracil (VII) intermediates. Where ionization is precluded, as with 1‐methyl derivatives (IVb, VIb) displacements are retarded but may be assisted by addition of a nucleophilc to the 6‐position of the heterocycle. Analogous 1,3‐dialkylpyrimidines may react with nucleophiles at the 4‐carbonyl group to give anomalous products. Biological connotations of these reactions are discussed.
The stereochemical assignments of the four 8‐azaestrone configurational isomers
Authors: Brown Richard K. , Meyers A. I. , Trefonas L. M. , Towns R. L. R. , Brown J. N. 
Published: March 2009

AbstractComplete correlation has now been accomplished for the four possible isomers in the 8‐azacstrone scries, synthesized by two different synthetic routes.
Studies on quinoline derivatives and related compounds. 1. A new synthesis of 1‐alkyl‐1,4‐dihydro‐4‐oxo‐3‐quinolinecarboxylic acids
Authors: Agui Hideo , Mitani Toru , Nakashita Mitsuo , Nakagome Takenari 
Published: March 2009

AbstractA novel preparative method for 1‐alkyl‐1,4‐dihydro‐4‐oxo‐3‐quinolinecarboxylic acids was developed. The key process is the cyclization of N‐alkylanilinomethylenemalonales, which was effected successfully in the presence of polyphosphoric acid, polyphosphate ester, boron tri‐fluoride or a mixture of acetic anhydride and sulfuric acid. With phosphorus oxychloride, N‐alkylanilinomethylenemalonates yielded 1‐alkyl‐4‐chloro‐3‐carbethoxyquinolinium salts which were hydrolyzed readily to ethyl 1‐alkyl‐1,4‐dihydro‐4‐oxo‐3‐quinolineearboxylates or their acids. By means of this novel method several new 1‐alkyl‐1,4‐dihydro‐4‐oxo‐3‐quinolineearboxylic acids were prepared.
The synthesis and chemical reactivity of 6‐selenoguanosine and certain related derivatives
Authors: Milne George H. , Townsend Leroy B. 
Published: March 2009

AbstractThe synthesis of 6‐selenoguanosine (2) has been accomplished by a nucleophilic displacement of the chloro group from 2‐amino‐6‐chloro‐9‐(β‐D‐ribofuranosyl)purine (1) with either selenourea or sodium hydrogen selenide. Treatment of 2 with Raney nickel has revealed that the seleno group can be removed much easier under these conditions than the corresponding mercapto group. Alkylation of 2 with several alkylating agents occurred at the exocyclic 6‐seleno group to furnish several 6‐alkylseleno‐2‐amino‐9‐(β‐D‐ribofuranosyl)purines. Nucleophilic displacement of the 6‐benzylseleno group from 2‐amino‐6‐benzylseleno‐9‐(β‐D‐ribofuranosyl)purine (3c) with sodium methoxide has been observed to occur at a faster rate than that observed for the corresponding 6‐benzylmercapto derivative. A study on the relative stability between 2 and 6‐seleno‐9‐(β‐D‐ribofuranosyl)purine toward basic conditions has revealed that the amino group at position two imparts an increase in stability.