bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of some new 4‐imino‐3,5,7‐trisubstituted‐pyrido[2,3‐d]pyrimidine‐2(1H)‐thiones
Authors: Verma S. S. , Taneja P. , Mital R. L. , Prakash L. 
Published: April 2009

AbstractThe synthesis of 4‐imino‐3,5,7‐trisubstituted‐pyrido[2,3‐d]pyrimidine‐2(1H)‐thiones is described. The elemental analysis, ir and nmr spectral data confirm the structure of the products.
Selenium dioxide oxidation of tetrahydro‐β‐carboline derivatives
Authors: Gatta Franco , Misiti Domenico 
Published: April 2009

AbstractThe oxidation of some tetrahydro‐β‐carboline derivatives with selenium dioxide led to the formation of 1,4‐dihydro or fully aromatic β‐carbolines, depending on the nature and the number of substituents at 1 position. The oxidation of 2‐acetyl derivatives followed a different course and the products originated by the attack at C‐1 of the ring C of the tetrahydro‐β‐carboline were obtained.
Photochemistry of 4‐phenyl‐1,3‐dioxolan‐2‐one
Authors: White Rick C. , Ma Sha 
Published: April 2009

AbstractThe photolysis of the mono substituted cyclic carbonate ester 4‐phenyl‐1,3‐dioxolan‐2‐one has been studied. The direct irradiation results in loss of carbon dioxide with the formation of the corresponding ox‐irane, styrene oxide as well as phenylacetaldehyde and bibenzyl. Photolysis in methanol produces the same compounds in addition to phenethyl alcohol and 2‐methoxy‐2‐phenylethanol. Triplet sensitized photolyses resulted in the products derived entirely from benzyl radicals with none of the oxirane being detected.
Tandem arylation‐reduction of acyl heterocycles. Convenient synthesis of benzyl heterocycles
Authors: Hall Stan S. , Farahat Sami E. 
Published: April 2009

AbstractTandem arylation‐reduction of a series of acyl heterocycles using phenyl‐, 4‐methylphenyl‐, and 4‐methoxy‐phenyllithium reagents followed by lithium‐ammonia‐ammonium chloride reduction afforded the corresponding benzyl heterocycles. The acyl heterocycles surveyed in this study contained furan, 2,3‐dihydro‐4H‐1‐benzopyran, 4H‐1‐benzopyran, thiophene, 4,5,6,7‐tetrahydrobenzo[b]thiophene, 2,3‐dihydro‐4H‐1‐benzothiopyran, and pyridine nuclei. All acyl heterocycles yielded the corresponding benzyl heterocycles except 2,3‐dihydro‐4H‐1‐benzothiopyran‐4‐one, which selectively cleaved during reduction to give the corresponding 2‐(1‐arylpropyl)benzenethiols.
Further study on 1,3‐dialkylaminouracil with dimethyl acetylenedicarboxylate
Authors: Itoh Tsuneo , Fujii Ikuko , Tomii Yasuo , Ogura Haruo , Mizuno Yoshihisa , Kawahara Norio 
Published: April 2009

AbstractOn the treatment of 1,3‐dialkyl‐6‐alkylaminouracil (1) with dimethyl acetylenedicarboxylate (DMAD), we were able to develop a new synthesis of deazapurine (pyrrolo[2,3‐d]pyrimidine, 4), and proposed the plausible mechanism for the formation of 3 and 4 from the adduct [dimethyl 2‐(1,3‐dialkyl‐6‐alkylamino‐2,4‐dioxopyrimidin‐5‐yl)fumarate, 2] of 1 with DMAD.
A convenient synthesis of novel pyridazino[3,4‐b]quinoxalines
Authors: Kurasawa Yoshihisa , Arai Harumi , Arai Kiyoko , Satoh Atsushi , Ninomiya Satoyuki , Okamoto Yoshihisa , Takada Atsushi 
Published: April 2009

AbstractNovel 4‐chlorophenylhydrazono‐3‐oxo‐1,2,3,4‐tetrahydropyridazino[3,4‐b]quinoxalines 10a‐c were synthesized by the cyclization of the α‐hydrazonohydrazides 8a‐c. The chlorination of 10a with phosphoryl chloride afforded 3‐chloro‐4‐[2‐(o‐chlorophenyl)hydrazino]pyridazino[3,4‐b]quinoxaline 12.
The synthesis of 5‐ and 6‐acyl‐2(1H)‐pyrimidinones
Authors: Jones Winton D. , Huber Edward W. , Grisar J. Martin , Schnettler Richard A. 
Published: April 2009

AbstractThe synthesis of 5‐acyl‐2(1H)‐pyrimidinones is described. In addition, one example of the hitherto unknown 6‐acyl‐2(1H)‐pyrimidinones has been prepared.
A new method for the synthesis of novel 6‐quinoxalinylpyrazolo[5,1‐c][1,2,4]triazines
Authors: Kurasawa Yoshihisa , Satoh Atsushi , Ninomiya Satoyuki , Arai Harumi , Arai Kiyoko , Okamoto Yoshihisa , Takada Atsushi 
Published: April 2009

AbstractThe reaction of the quinoxaline 1 with 4‐ethoxycarbonyl‐1H‐pyrazole‐5‐diazonium chloride 7 at room temperature gave 3‐[α‐(4‐ethoxycarbonyl‐1H‐pyrazol‐5‐ylhydrazono)methoxycarbonylmethyl]‐2‐oxo‐1,2‐dihydroquinoxaline 8. The pmr spectrum of 8 in deuteriodimethylsulfoxide supported the presence of two tautomers 8‐I and 8‐II. Refluxing of 8 in N,N‐dimethylformamide or acetic acid resulted in cyclization to afford 8‐ethoxycarbonyl‐4‐oxo‐3‐(3‐oxo‐3,4‐dihydroquinoxalin‐2‐yl)‐1,4‐dihydropyrazolo[5,1‐c][1,2,4]triazine 9. Compound 9 was also obtained directly by the reaction of 1 with 7 under reflux in better yield. The reaction of 9 with hydrazine hydrate provided the hydrazinium salt 10, while the reactions of 9 with triethyl and trimethyl orthoformates in the presence of 1,8‐diazabicyclo[5,4,0]‐7‐undecene produced 8‐ethoxycarbonyl‐4‐ethoxyl‐3‐(3‐oxo‐3,4‐dihydroquinoxalin‐2‐yl)pyrazolo[5,1‐c][1,2,4]triazine 11a and 8‐ethoxycarbonyl‐4‐methoxyl‐3‐(3‐oxo‐3,4‐dihydroquinoxalin‐2‐yl)pyrazolo[5,1‐c][1,2,4]triazine 11b, respectively. The chlorination of 11a with phosphoryl chloride gave 3‐(3‐chloroquinoxalin‐2‐yl)‐8‐ethoxycarbonyl‐4‐ethoxylpyrazolo[5,1‐c]‐[1,2,4]triazine 12, whose reaction with morpholine afforded 8‐ethoxycarbonyl‐4‐ethoxyl‐3‐[3‐(morpholin‐4‐yl)‐quinoxalin‐2‐yl]pyrazolo[5,1‐c][1,2,4]triazine 13.
Asymmetric synthesis via heterocyclic intermediates. I. Synthesis of 3,4‐dihydro‐11a‐(S)‐methyl‐4‐(R)‐phenyl‐1,4‐oxazino[4,3‐b]isoquinolin‐1(6H,11H)‐one
Authors: Marco José L. 
Published: April 2009

AbstractThe synthesis of 3,4‐dihydro‐11a‐(S)‐methyl‐4‐(R)‐phenyl‐1,4‐oxazino[4,3‐b]isoquinoline‐1(6H,11H)‐one 1 is described.
N‐Arylation of isatins. A direct route to N‐arylisatoic anhydrides
Authors: Coppola Gary M. 
Published: April 2009

AbstractThe synthesis of N‐arylisatoic anhydrides 3 has been accomplished by using a two‐step process. The key reaction in the sequence is the direct N‐arylation of isatin with an aryl bromide in the presence of cupric oxide. Subsequent oxidation of the resulting N‐aryl isatin 2 with m‐chloroperoxybenzoic acid furnishes the desired products.
Reduction products of 3(2H)‐cinnolinones
Authors: Zey Robert L. 
Published: April 2009

AbstractReduction of 3(2H)‐cinnolinone with zinc and ammonium hydroxide forms 1,4‐dihydro‐3(2H)‐cinnolinone which rapidly rearranges to 1‐amino‐2‐indolinone (1‐aminooxindole) in acid solution. 1,4‐Dihydro‐2‐methyl‐3(2H)‐cinnolinone is formed from 2‐methyl‐3(2H)‐cinnolinone under the same conditions, but its rearrangement to 1‐(N‐methylamino)‐2‐indolinone (1‐(N‐methylamino)oxindole) in acid solution is much slower.
Pseudoesters and derivatives. XXV. 1,3‐Dipolar cycloaddition of diazomethane to 5‐methoxy‐3‐pyrrolin‐2‐ones
Authors: Fariña Francisco , Martín M. Victoria , Paredes M. Carmen , Tito Amelia 
Published: April 2009

AbstractCycloaddition of diazomethane to pyrrolinones 1a,b,d,e affords only one regioisomer as a mixture of the epimeric pyrrolopyrazolines 2 and 2′,4‐Halo derivatives 1f,g react with diazomethane to give the two possible regioisomers 2 and 3. The regio‐ and stereochemistry of the adducts is evidenced by the 1H‐nmr data. The primary adducts originated from the halopyrrolinones suffer dehydrohalogenation to give aromatized products, which by further methylation give derivatives of type 7, 8, 10 and 11.
Fused v‐triazolo‐heterocycles. Part 2. Synthesis of 4H‐v‐triazolo[1,5‐d] [1,3,4]oxadiazin‐4‐ones from the 1‐aroylamino‐v‐triazole‐5‐carboxylic acids
Authors: Rodios Nestor A. 
Published: April 2009

AbstractThe synthesis of some 4H‐v‐triazolo[1,5‐d] [1,3,4]oxadiazin‐4‐ones is described. They are prepared by the reaction of the corresponding 1‐aroylamino‐v‐triazole‐5‐carboxylic acids with thionyl chloride in the presence of pyridine. The spectroscopic data of these new compounds are also reported.
Mesoionic isoxazolo[2,3‐a]pyrimidinediones and 1,3,4‐oxadiazolo[3,2‐a]pyrimidinediones as potential adenosine antagonists
Authors: Shehata Ihsan A. , Glennon Richard A. 
Published: April 2009

AbstractSeveral derivatives of two novel mesoionic ring systems, i.e., isoxazolo[2,3‐a]pyrimidinedione and 1,3,4‐oxadiazolo[3,2‐a]pyrimidinedione, were prepared for evaluation as adenosine antagonists. Whereas both ring systems are relatively stable when the 6‐position (i.e., that position corresponding to the purine 1‐position) is substituted by an alkyl group, neither ring system is stable when this position is unsubstituted. An example of a 6‐unsubstituted non‐mesoionic isoxazolopyrimidinedione exhibited similar behavior. As adenosine antagonists, the mesoionic compounds were found to be less potent than their previously evaluated mesoionic thiadiazolo[3,2‐a]pyrimidinedione counterparts.
Synthesis of perhydro‐2(1H)‐quinoxalinones and perhydropyrrolo[1,2‐a]quinoxalin‐4(5H)‐one derivatives
Authors: Rees David C. 
Published: April 2009

AbstractThe noveltrans‐bicyclic‐perhydro‐2(1H)‐quinoxalinones4, 6and7and the tricyclic‐perhydropyrrolo[1,2‐a]‐quinoxalin‐4(5H)‐one derivatives8and9are preparedviaa ring opening and spontaneous ring closing reaction of the aziridines2and3with the α‐amino acids glycine, L‐alanine, L‐proline and L‐phenylalanine. This methodology was used to prepare5and10which are novel rigid analogues of the kappa opioid compound1.Treatment of aziridine3with methyl carbamate gave the cyclic urea11.
Reactions of methyl 3‐hydroxythiophene‐2‐carboxylate. Part 4. Synthesis of methyl 5‐azolyl‐3‐hydroxythiophene‐2‐carboxylates
Authors: Corral Carlos , El‐Ashmawy Mahmoud B. , Lissavetzky Jaime , Manzanares Ignacio 
Published: April 2009

AbstractThe indirect introduction of an azolyl group in position 5 of compound 1 by an easy two‐step procedure taking place at room temperature is described. A similar procedure yields the 4‐chloro derivatives of these 5‐azolyl compounds. The same method is applied for the introduction of a 5‐azido group and from the 5‐azido compounds, 5‐v‐triazolyl derivatives are obtained by a known method.
A convenient synthesis of 2‐substituted 4‐amino‐5‐pyrimidinecarbonitriles
Authors: Schmidt Hans‐Werner , Koitz Gerald , Junek Hans 
Published: April 2009

AbstractSynthesis of the novel 2‐halogenated 4‐amino‐5‐pyrimidinecarbonitriles 3a,b starting from ethoxy‐methylenemalononitrile 1 and cyanamide is described. Nucleophilic substitution of the reactive halogen atom leads to the derivatives 5a‐g, 6 and 7a‐h.
Enzymatic halogenation of pyrazoles and pyridine derivatives
Authors: Franssen M. C. R. , Van Boven H. G. , Van Der Plas H. C. 
Published: April 2009

AbstractPyrazole, 1‐methylpyrazole and 3‐methylpyrazole are chlorinated by the enzyme chloroperoxidase from Caldariomyces fumago, in the presence of potassium chloride and hydrogen peroxide at pH 2.7, yielding the corresponding 4‐chloro derivatives in good yields. A 4H‐pyrazole is proposed as an intermediate in this reaction. 2‐Aminopyridine was converted regiospecifically by the same enzyme into 2‐amino‐3‐chloropyridine, and 8‐hydroxyquinoline gave its 5,7‐dibromo‐derivative in very good yield when bromide ion was used as the halide substrate.
The fischer indolisation of (±)‐3‐methylcyclopentanone phenylhydrazone
Authors: Robinson Brian 
Published: April 2009

AbstractFischer indolisation of (±)‐3‐methylcyclopentanone phenylhydrazone under three different conditions affords in each case a mixture of (±)‐1‐and 2‐methyl‐1,2,3,4‐tetrahydrocyclopent[b]indoles 4b and 4a, respectively. These mixtures were quantitatively analysed using proton nuclear magnetic resonance spectroscopy and their recrystallisation led to the isolation of compound 4a. The structure of this was distinguished from the isomeric structure 4b by its oxidation with 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone to afford compound 4c, the ultraviolet spectrum of which was characteristic of a 3‐ and not a 2‐ acylindole chromophore and was almost superimposable upon that of the model compound 4d.
Synthesis and reactions of 7‐substituted 1‐cyclopropyl‐6‐fluoro‐1,4‐dihydro‐4‐oxo‐1,8‐naphthyridine‐3‐carboxylic acids as an antibacterial agent
Authors: Miyamoto Teruyuki , Egawa Hiroshi , Shibamori Koh‐Ichiro , Matsuraoto Jun‐Ichi 
Published: April 2009

Abstract1‐Cyclopropyl‐ and 1‐ethyl‐6‐fluoro‐1,4‐dihydro‐4‐oxo‐1,8‐naphthyridine‐3‐carboxylic acid derivatives having a sulfinyl or sulfonyl group at C‐7 were synthesized from 2,6‐dichloro‐5‐fluoronicotinic acid derivatives by the route involving the Dieckmann‐type cyclization. The displacement reactions of these compounds with pyrrolidine and piperidine gave mainly the 7‐(1‐pyrrolidinyl)‐ and 7‐(1‐piperidinyl)‐1,8‐naphthyridine derivatives 24‐27, respectively. Enoxacin, a potent antibacterial agent, was also synthesized with the analogous route.
Regioselectivity in lateral deprotonation of an isoxazolecarboxamide of (S)‐prolinol. Conformational correlation by crystal structure solid state solution 13C NMR
Authors: Schlicksupp Ludwig , Natale N. R. 
Published: April 2009

AbstractThe conformation at the amide functional group in 3,5‐dimethylisoxazole‐4‐(S‐2′‐hydroxymethyl‐N‐pyrrolidino) carboxamide (1) has been determined by a single crystal X‐ray determination. The 13C nmr in both deuteriochloroform solution and solid state show close agreement. The metalation behaviour of the amide is dependent upon the substitution on the 2′‐hydroxymethyl moiety. Dianion studies indicate C‐5 lateral metalation under both thermodynamic and kinetic conditions. Protection of this substituent as the methyl ether, 2, gives rise to predominant C‐3 lateral metalation under kinetic conditions and C‐5 lateral metalation on equilibration. These observations can be explained using the Ireland‐Evans model for chelation directed deprotonation.
Formation of reissert analogs from benzimidazole and use of carboxylic acids in a retro‐reissert reactionReissert Analogs from Benzimidazole
Authors: Uff Barrie C. , Ho Yee‐Ping , Burford Donald L. W. , Popp Frank D. 
Published: April 2009

AbstractReissert analogs have been formed in high yields from benzimidazole using trimethylsilyl cyanide and chloroformates. A retro‐Reissert reaction can be effected on the products, their carbon‐2 alkylated derivatives and benzothiazole analogs, by treatment with hexanoic or benzoic acids.
1‐Alkoxycarbonyl‐ and 1‐acyl‐v‐triazolo[4,5‐b]‐pyridine/hydrogen peroxide oxygenating systems
Authors: Zecchini Giampiero Pagani , Torrini Ines , Paradisi Mario Paglialunga 
Published: April 2009

AbstractEpoxidation of alkenes and oxidation of thioanisole to the corresponding sulfoxide was achieved using the 1‐alkoxycarbonyl‐ or 1‐acyl‐v‐triazolo[4,5‐6]pyridine/hydrogen peroxide systems. High yields of epoxide or sulfoxide were observed when some amide‐type triazolides were employed for the oxidizing method.
A new synthesis of imidazo[1,2‐a]pyridine and imidazo[2,1‐a]isoquinoline derivatives
Authors: Tominaga Yoshinori , Motokawa Shigenori , Shiroshita Yoshihide , Hosomi Akira 
Published: April 2009

AbstractA new synthesis of imidazo[1,2‐a]pyridine and imidazo[2,1‐a]isoquinoline derivatives 4 and 8, respectively by 1,5‐dipolar cyclization reactions of stabilized pyridinium N‐ylides 3a‐e or isoquinolinium N‐ylide 7 is described. The starting N‐ylides 3a‐e and 7 are prepared by the reaction of the corresponding pyridinium salts 1a‐e or isoquinolinium salts 6 with N‐bis(methylthio)methylene‐p‐toluenesulfonamide (2).
Studies on pyrazines. 16 . Palladium‐catalyzed cyanation of 2‐amino‐5‐bromopyrazines
Authors: Sato Nobuhiro , Suzuki Masakazu 
Published: April 2009

AbstractWe report here a synthesis of 2‐amino‐5‐cyano‐ 3 and 2‐amino‐3,5‐dicyanopyrazines 4 by palladium(0)‐catalyzed cyanation of the corresponding pyrazine amino bromides 1 and 2.
An improved, large‐scale synthesis of xanthothricin and reumycin
Authors: Black T. Howard 
Published: April 2009

AbstractXanthothricin (toxoflavin) has been synthesized in high yield and on a large (over 100 g) scale; this was selectively demethylated at N‐1 to produce reumycin (1‐demethyltoxoflavin) employing an optimized purification protocol also amenable to large‐scale production.
Fluorescence reagents. I. Derivatization of carboxylic acids, imides and alcohols with 1‐chloromethylbenz[c,d]indol‐2(1H)‐one (CMBI)
Authors: Wendelin Winfried , Gübitz Gerald , Pracher Ulrike 
Published: April 2009

AbstractThe derivatization and fluorodensitometric determination of carboxylic acids (CA), imides and alcohols with 1‐chloromethylbenz[c,d]indol‐2(1H)‐one (19, CMBI) have been studied. Out of a series of fluorescent fused lactams 9‐11, 13‐15 and 17, benzindolone 17 was selected and transformed via hydroxymethylbenzin‐dolone 18 into CMBI 19. CMBI reacts with CA, diCA and alcohols respectively to yield strongly fluorescent benz[c,d]indol‐1‐ylmethyl esters 20, 21 (BIM esters) and BIM ethers 22. Phenobarbital is transformed by action of CMBI into fluorescent 1,3‐bisBIM phenobarbital 25. Studies on the applicability of the derivatization reactions to the fluorodensitometric determination of CA, alcohols and imides showed that CA with more than 3 carbon atoms can be determined via BIM esters down to the low picomole range. In the case of alcohols and imides the results were not satisfying. The ir, uv, fluorescence, nmr and mass spectra of the prepared benzindole derivatives are also presented.
Synthesis of trifluoromethyltriazoles from trifluoroacetohydrazonoyl bromide
Authors: Tanaka Kiyoshi , Honda Osamu , Minoguchi Kazumi , Mitsuhashi Keiryo 
Published: April 2009

AbstractN‐Phenyltrifluoroacetohydrazonoyl bromide (1) reacted with potassium isothiocyanate and isocyanate to give 5‐imino‐4‐phenyl‐2‐trifluoromethyl‐δ2‐1,3,4‐thiadiazoline and 1‐phenyl‐3‐trifluoromethyl‐δ2‐1,2,4‐triazolin‐5‐one, respectively. On treatment with several types of cumulative double bonds such as alkyl isothiocyanate, isocyanate, and carbodiimide, 1 afforded regioselectively the corresponding trifluoromethylthiadiazoline, ‐oxadiazoline, and ‐triazoline, respectively. These cycloadducts were assumed to form through the stepwise path involving the addition of 1 toward the cumulative double bond followed by the intramolecular cyclization. Concerning cyanamides, the corresponding triazoles were obtained and the reactions with pyridines afforded the triazolopyridinium bromides. The reactivity of the latter was found to depend on the substituents on the pyridine nucleus.
Crystal and molecular structure of 5,5‐dimethyl‐δ1‐1,2,4‐triazolin‐3‐one
Authors: Schantl Joachim G. , Gstach Hubert , Lanznaster Norbert , Gieren Alfred , Lamm Viktor 
Published: April 2009

AbstractThe spectroscopic and X‐ray data of the title compound are presented and discussed. Some anomalies are attributed to the lack of conjugation between the diazene and carbonyl group, and to the association of the molecules in the solid state through an unusual intermolecular hydrogen bond between the amide nitrogen atom and the diazene nitrogen atom N2.
Potential DNA bis‐intercalating agents: Synthesis and antitumor activity of novel, conformationally restricted bis(9‐aminoacridines)
Authors: Jaycox Gary D. , Gribble Gordon W. , Hacker Miles P. 
Published: April 2009

AbstractA series of bis(9‐aminoacridines) bridged by conformationally restricted tethers was synthesized and evaluated against L1210 in vitro. Several of these compounds were found to be highly active in this test system, with ID50 values below 10−7 M. CPK molecular models suggest that this antitumor activity can be correlated to the ability of these bis(9‐aminoacridines) to form bis‐intercalative complexes with DNA.
Acetylenchemie 6. Mitt.: Propinylierung von N‐Methylbarbitursäuren nach dem PTC‐ und phosphoroxychlorid‐verfahren ‐ nachweis zweier mechanismen bei der chromenbildung von pyrano[3,2‐c]chinolin‐alkaloiden
Authors: Reisch Johannes , Bathe Andreas 
Published: April 2009

AbstractDer Mechanismus der Furan‐/Pyrananellierung von 1,3‐Dicarbonylverbindungen via Propinyl‐Zwischen‐stufen wird am Barbitursäuremodell studiert; er wechselt mit der Alkylierungsbedingung: Bei phasentransferkatalysierter (PTC) Umsetzung von N,N′‐Dimethylbarbitursäure mit 3‐Bromprop‐1‐in erfolgt Dipropinylierung, während mit 3‐Chlor‐3‐methylbut‐1‐in ein Furopyrimidon entsteht. Eine Variante mit dem Alkylans 3‐Hydroxy‐3‐methylbut‐1‐in/Phosphoroxytrichlorid führt zur 3′‐Methylbuta‐5,2′‐dienyl‐Anordnung, der Pyranvorstufe. Diese entsteht auch mit N‐Methylbarbitursäure. Die unterschiedlichen Entstehungswege werden diskutiert, die Ergebnisse mit früheren Arbeiten verglichen.
Heterocycles. XIII. Nls orbital binding energies of some quinazolines and pyrimidines by XPS
Authors: El‐Rayyes N. R. , Katrib A. , Al‐Kharafi F. M. , El‐Issa B. D. 
Published: April 2009

AbstractThe X‐ray photoelectron spectra of some quinazolin‐2(1H)‐ones IIa,b, show only one relatively symmetrical line in the N1s binding‐energy region, where as the corresponding dehydrogenated products IIIa,b and the pyrimidin‐2‐(1H)‐ones Va,b revealed two well‐resolved spectral lines with an energy difference of more than 1 eV. However, compounds IIc and IIIc gave only one broad unsymmetrical line.Quantum mechanical calculations on compounds IIa and IIIa as well as analogues IIc and IIIc supported the experimental findings.
Part 4. Fused pyrimidines. Annelation using formamide to synthesize 2,4‐disubstituted‐pyrimido[4,5‐d]pyrimidines
Authors: Delia Thomas J. , Niedzinski Jill 
Published: April 2009

AbstractA one‐step synthesis of 2,4‐disubstituted‐pyrimido[4,5‐d]pyrimidines has been investigated. Cyclization of 6‐amino‐2,4‐disubstituted‐pyrimidines with formamide as solvent and reagent affords the title compounds in 50‐70% yield. Strongly electron‐donating groups are required. Based on model compounds, a pathway for the cyclization is suggested. The method is an improvement on previous methods of synthesis, albeit a limited one.
The mass spectral fragmentation of isoxazolyldihydropyridines
Authors: Knerr Gary , Mckenna John I. , Quincy David A. , Natale N. R. 
Published: April 2009

AbstractThe mass spectral fragmentation of 4‐isoxazolyl‐1,4‐dihydropyridines has been examined with the aid of linked metastable scanning. Three prominent pathways involve (i) O‐N bond cleavage of the isoxazole followed by the loss of R2CN, (ii) loss of carboalkoxy from the 3‐ and/or 5‐ position of the dihydropyridine and, (iii) loss of the 4‐isoxazolyl‐substituent.
Triazolotriazines as potential chemotherapeutic agents. VI
Authors: Ram Vishnu J. , Dube Vidyohama , Vlietinck A. J. 
Published: April 2009

AbstractSeveral new 1,2,4‐triazolo[4,3‐b]triazino[7,6‐b]indoles were prepared in anticipation that they would have better chemotherapeutic activities, but in the Screening test none of the Compounds was found to be active.
Studies on decarboxylation reactions. Part 5. Micellar catalysis and mixed solvents effects on the decarboxylation of some N‐alkyl‐ or N‐aryl‐substituted 5‐amino‐1,3,4‐oxadiazole‐2‐carboxylic acids
Authors: Noto Renato , Buscemi Silvestre , Werber Giuseppe , Spinelli Domenico 
Published: April 2009

AbstractThe effect of micelles and mixed solvents on the decarboxylation of some N‐alkyl‐ or N‐aryl‐substituted 5‐amino‐1,3,4‐oxadiazole‐2‐carboxylic acids has been studied. The data support the unimolecular decarboxylation mechanism proposed by us. Moreover, they show that mixed solvents and micelles have different effects on reactivity of the amino acids under study.