bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular dynamics simulations of the detoxification of paraoxon catalyzed by phosphotriesterase
Authors: Zhang Xin , Wu Ruibo , Song Lingchun , Lin Yuchun , Lin Menghai , Cao Zexing , Wu Wei , Mo Yirong
Published: April 2009

Combined QM(PM3)/MM molecular dynamics simulations together with QM(DFT)/MM optimizations for key configurations have been performed to elucidate the enzymatic catalysis mechanism on the detoxification of paraoxon by phosphotriesterase (PTE). In the simulations, the PM3 parameters for the phosphorous atom were reoptimized. The equilibrated configuration of the enzyme/substrate complex showed that paraoxon can strongly bind to the more solvent‐exposed metal ion Znβ, but the free energy profile along the binding path demonstrated that the binding is thermodynamically unfavorable. This explains why the crystal structures of PTE with substrate analogues often exhibit long distances between the phosphoral oxygen and Znβ. The subsequent SN2 reaction plays the key role in the whole process, but controversies exist over the identity of the nucleophilic species, which could be either a hydroxide ion terminally coordinated to Znα or the μ‐hydroxo bridge between the α‐ and β‐metals. Our simulations supported the latter and showed that the rate‐limiting step is the distortion of the bound paraoxon to approach the bridging hydroxide. After this preparation step, the bridging hydroxide ion attacks the phosphorous center and replaces the diethyl phosphate with a low barrier. Thus, a plausible way to engineer PTE with enhanced catalytic activity is to stabilize the deformed paraoxon. Conformational analyses indicate that Trp131 is the closest residue to the phosphoryl oxygen, and mutations to Arg or Gln or even Lys, which can shorten the hydrogen bond distance with the phosphoryl oxygen, could potentially lead to a mutant with enhanced activity for the detoxification of organophosphates. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2009
Correction of carotid intima‐media thickness for adaptive dependence on tensile stress: Implication for cardiovascular risk assessment
Authors: Chironi Gilles N. , Simon Alain , Bokov Plamen , Levenson Jaime
Published: April 2009

Purpose.

Early artery wall‐thickening detected by ultrasound‐assessed increased carotid intima‐media thickness (IMT) may reflect atherosclerosis or represent an adaptive response to keep homeostasis tensile stress that is related inversely to wall thickness by Laplace's equation. We attempted to discriminate between both mechanisms by correcting IMT for its inverse association with tensile stress.

Methods.

Common carotid IMT and lumen diameter (D) where determined in 40 healthy controls and 119 never‐treated asymptomatic patients with ≥1 traditional cardiovascular risk factor. The cross‐sectional area (CSA) was calculated as π × IMT × (IMT + D). Tensile stress was approximated by [mean blood pressure × (D/2 × IMT)], and wall shear stress by [(blood viscosity) × 4 × (mean blood velocity/D)]. Inverse regression line relating IMT and tensile stress in controls (p < 0.001) was used as a reference to determine in an individual at‐risk patient the IMT deviation, defining ΔIMT from the regression line of controls at the measured patient's tensile stress.

Results.

ΔIMT correlated positively with age (p < 0.05), body mass index (p < 0.05), blood pressure (p < 0.001), and glucose (p < 0.001). In multivariate analysis, ΔIMT was independently associated with age (p < 0.01), male gender (p < 0.001), and blood pressure (p < 0.001). IMT showed positive association with age (p < 0.001) but not with other risk factors. Also, ΔIMT, like CSA, correlated positively with tensile stress (p < 0.001) and negatively with wall shear stress (p < 0.05, p < 0.01), whereas IMT correlated negatively with tensile stress (p < 0.001) but not with wall shear stress.

Conclusion.

Correcting IMT for adaptive association with tensile stress may give more strength to carotid evaluation for assessing cardiovascular risk. © 2009 Wiley Periodicals, Inc. J Clin Ultrasound, 2009
Prenatal diagnosis by 3D ultrasound and MRI of an unusual malformation of cortical development with brain‐in‐brain appearance
Authors: Valsecchi Luca , Cavoretto Paolo , Di Piazza Lara , Smid Maddalena , Pontesilli Silvia , Scotti Roberta , Spagnolo Daniele , Baldoli Cristina
Published: April 2009

A 31‐year‐old pregnant woman was referred for isolated mild ventriculomegaly and failure to visualize the left lateral ventricle's anterior horn on second trimester sonography (US). Three‐dimensional US suspected a frontal lesion deviating the midline. MRI revealed a mass compressing the ventricle. Follow‐up MRI described a “brain‐in‐brain” malformation: infolded microgyric cortex and white matter in frontal lobe extending to frontal horn and midline, irrorated by hypertophic Heubner artery. Conservative approach was chosen. Neurodevelopment at 1 year is normal. © 2009 Wiley Periodicals, Inc. J Clin Ultrasound, 2009
Measuring microenvironment mechanical stress of rat liver during diethylnitrosamine induced hepatocarcinogenesis by atomic force microscope
Authors: Gang Zhao , Qi Qin , Jing Cui , Wang Chunyou
Published: April 2009

We developed a highly sensitive method to detect liver tissue stiffness with atomic force microscopy (AFM), and investigated the physical features of hepatocarcinogenesis. Wistar rats received weekly intraperitoneal injections of diethylnitrosamine (DEN) or saline (control) followed by a 2‐week wash‐out period. Liver samples were harvested at 10, 14, or 18 weeks for pathological examination and stress detection. Previously normal liver tissues developed fibrosis and carcinoma after DEN administration. Although the elastic modulus (E) values of the normal (saline; 0.18 ± 0.04 MPa), fibrotic (8 weeks DEN; 0.25 ± 0.06 MPa) and cirrhotic (12 weeks DEN; 0.39 ± 0.06 MPa) tissues were significantly different, there was no significant difference between the E values of the cirrhotic and the hepatic cell carcinoma (16 weeks DEN; 0.42 ± 0.07 MPa) tissues. Thus, tissue stiffness quantitatively increases during hepatocarcinogenesis, and AFM can be used to sensitively and precisely detect liver stiffness at the microscopic level. Microsc. Res. Tech. 2009. © 2009 Wiley‐Liss, Inc.
5‐HT 1A and 2A receptor positive cells in the cerebella of mice and human and their decline during aging
Authors: Yew David T. , Yeung Lai‐Yin , Wai Maria Sen‐Mun , Mak Ying T.
Published: April 2009

This study evaluated the 5‐HT1A and 5‐HT2A receptor positive cells in the cerebella of mice and human by immunocytochemistry. Mice were of ages 1, 3, and 12 months whereas the human subjects were divided into two groups, a younger 57–78 years old group and an older 82–91 years old group. Both 5‐HT1A and 5‐HT2A receptor positive cells were observed in the molecular and granular layers of the cerebella of mice and human. Although there was a decline in these positive cells during aging, no regional difference in the positive cells were observed in the anterior, middle, and posterior regions of the cerebella. Microsc. Res. Tech. 2009. © 2009 Wiley‐Liss, Inc.
Maximum directed cuts in digraphs with degree restriction
Authors: Lehel Jenö , Maffray Frédéric , Preissmann Myriam
Published: April 2009

For integers m, k≥1, we investigate the maximum size of a directed cut in directed graphs in which there are m edges and each vertex has either indegree at most k or outdegree at most k. © 2009 Wiley Periodicals, Inc. J Graph Theory
Acyclic edge coloring of graphs with maximum degree 4
Authors: Basavaraju Manu , Chandran L. Sunil
Published: April 2009

An acyclic edge coloring of a graph is a proper edge coloring such that there are no bichromatic cycles. The acyclic chromatic index of a graph is the minimum number k such that there is an acyclic edge coloring using k colors and is denoted by a′(G). It was conjectured by Alon, Sudakov, and Zaks that for any simple and finite graph G, a′(G)⩽Δ + 2, where Δ=Δ(G) denotes the maximum degree of G. We prove the conjecture for connected graphs with Δ(G)⩽4, with the additional restriction that m⩽2n−1, where n is the number of vertices and m is the number of edges in G. Note that for any graph G, m⩽2n, when Δ(G)⩽4. It follows that for any graph G if Δ(G)⩽4, then a′(G)⩽7. © 2009 Wiley Periodicals, Inc. J Graph Theory 61: 192–209, 2009
Generating 5‐regular planar graphs
Authors: Ding Guoli , Kanno Jinko , Su Jianning
Published: April 2009

For k=0, 1, 2, 3, 4, 5, let ${\cal{P}}_{k}$ be the class of k ‐edge‐connected 5‐regular planar graphs. In this paper, graph operations are introduced that generate all graphs in each ${\cal{P}}_{k}$. © 2009 Wiley Periodicals, Inc. J Graph Theory 61: 219–240, 2009
Anti‐Ramsey numbers of doubly edge‐critical graphs
Authors: Jiang Tao , Pikhurko Oleg
Published: April 2009

Given a graph H and a positive integer n, Anti‐Ramsey number AR(n, H) is the maximum number of colors in an edge‐coloring of Kn that contains no polychromatic copy of H. The anti‐Ramsey numbers were introduced in the 1970s by Erdős, Simonovits, and Sós, who among other things, determined this function for cliques. In general, few exact values of AR(n, H) are known. Let us call a graph H doubly edge‐critical if χ(H−e)≥p+ 1 for each edge e∈E(H) and there exist two edges e1, e2 of H for which χ(H−e1−e2)=p. Here, we obtain the exact value of AR(n, H) for any doubly edge‐critical H when n⩾n0(H) is sufficiently large. A main ingredient of our proof is the stability theorem of Erdős and Simonovits for the Turán problem. © 2009 Wiley Periodicals, Inc. J Graph Theory 61: 210–218, 2009
Heterocycles from substituted amides III. 1,2,3‐Oxathiazolidin‐4‐one 2‐oxides from thionyl chloride and α‐hydroxyacylanilides
Authors: Chupp John P.
Published: April 2009

A new heterocyclic series was synthesized for the first time, from reaction of thionyl chloride with α‐hydroxyacylanilides (1). Structural features of the resulting 1,2,3‐oxathiazolidin‐4‐one 2‐oxides (2) are discussed with particular reference to their spectral properties, and are compared with the previously reported 1,2,3‐oxathiazolidine 2‐oxides (3).
On the proton affinity of pteridine
Authors: Neiman Z.
Published: April 2009

All‐valence‐electron and perturbation calculations suggest that pteridine may preferably be protonated at the pyrazine moiety. Correlation between these results and some experimental data is presented.
Some derivatives of indeno[2,1‐g]pteridine
Authors: Saint‐Ruf C.
Published: April 2009

The condensation of indantrione monohydrate (ninhydrin) with ortho‐diamines derived from pyridine and pyrimidine led to the synthesis of several new indeno[2,1‐g]pteridine derivatives. The structure of these compounds is discussed and their physical properties described.
Polar cycloaddition reactions of some 2,3‐disubstituted isoquinolinium salts
Authors: Bradsher C. K. , Day F. Howard
Published: April 2009

The addition of four vinyl ethers and of cyclopentadiene to 2,3‐dimethylisoquinolinium salts occurs stereoselectively affording only syn adducts. The attack of nucleophiles on the vinyl ether adducts (4–9) occurs at position 3. Similar stereoselective cycloadditions may be carried out using berberinium chloride as the electrophile.
Heterocyclic derivalives of naphthalene‐1,8‐dicar boxylie anhydride. Part III. Benzo[k,l] thioxanthene‐3,4‐dicarboximides
Authors: Grayshan P. H. , Kadhim A. M. , Perters Arnold T.
Published: April 2009

Condensation of 4‐bromo‐ (4) and 4‐nilro‐l,8‐naphthalimides (5) with 2‐aminobenzenethiol gave 4‐(2‐aminoulicnylthio)‐1,8‐naphthalimides (7). Cyclisalion of 7 by the: Pschorr reaction afforded benzo[k,l] thioxanthene‐3,4‐dicarboximides (8), also obtained by reaction ol amities with benzo[k,l] thioxanthene‐3,4‐dicarboxylie anhydride (11).
1,2,4‐Triazines. XII. Syntheses of 5‐carboxarnido‐1,2,4‐triazines via an addition‐oxidation reaction
Authors: Krass Dennis K. , Paudler William W.
Published: April 2009

5‐Unsubstituted 1,2,4‐triazines, when treated with potassium cyanide suspended in moist dioxane afford 5‐carhoxamido as well as 5,5′ ‐bi‐1,2,4‐triazinyl derivatives. A probable reaction sequence is described.
Synthesis and reactions of 2‐aryl‐3‐(dimethylamino)acroleins
Authors: Coppola Gary M. , Hardtmann Goetz E. , Huegi Bruno S.
Published: April 2009

The preparation of a number of novel 2‐aryl‐3‐(dimethylamino)acroleins and their hydrolyses to 2‐arylmalondialdehydes is described. Reactions of the acroleins with amines are discussed as well as the conversion of the 2‐arylmalondialdehydes into 3‐chloro and 3‐alkoxyacroleins.
Properties of lipoic acid analogs
Authors: Shih Jason C. H. , Williams Paul B. , Wright Lemuel D. , Mccormick Donald B.
Published: April 2009

Two chain‐shortened analogs of lipoic (1,2‐dithiolane‐3‐pentanoic) acid, viz. bisnor‐lipoic (1,2‐dithiolane‐3‐propanoic) and tetranorlipoic (1,2‐dithiolane‐3‐carboxylic) acids, have been chemically synthesized. The ir, uv, pmr, and mass spectroscopic properties and paper, thin‐layer, and column chromatographic mobilities of lipoic acid and its analogs were investigated and are given.
Pyrolysis of 2‐(2‐azidobenzoyl)pyridine and 3‐(2‐Pyridyl)‐2,1‐ benzisixazoles. Prepration and chemistry of some pyrido[1,2‐b]cinnolin‐6‐ium hydroxide inner salts
Authors: Ning Robert Y. , Chen Wen Yean , Sternbach Leo H.
Published: April 2009

The pyrolysis of 3‐(2‐pyridyl)‐2,1‐benzisoxazoles 5A, 5B, and 5C (A: unsubstituted; B: 5‐bromo; C: 5,7‐dibromo) at about 215° afforded 5,11‐dihydro‐11‐oxopyrido [1,2‐b] cinnolin‐6‐ium hydroxide inner salt 6A, the 2‐bromo (6B) and the 2,4‐dibromo (6C) compounds respectively in high yields. X‐ray crystallographic analysis of 6B unambiguously confirmed the structure. The benzisoxazoles 5A‐5C were obtained from the pyrolysis of the corresponding 2‐(2‐azidobenzoyl) pyridines 2A‐2C at about 112°. While 2A and 2B afforded the corresponding benzisoxazoles 5a and 5B in 82% and 51% yields respectively, 2‐(2‐azido‐3,5‐dibromobenzoyl)pyridine (2C) afforded a mixture of the benzisoxazole 5C and the tricyclic compound 6C, isolated 43% and 41% yields respectively.

The properties of the novel mesoionic compounds of type 6, their oxidative and reductive ring cleavage products together with alkylation and catalytic hydrogenation products are described. Electrophilic substitutions, substitutions in position 11 via the 11‐thiones 11 and other miscellaneous trans of 6 are also presented.
Definition of the predominant tautomeric form of 3‐methyl‐1‐phenylpyrazoline‐5‐thione in solution by 1 H and 1 3C NMR spectroscopy
Authors: Bergman Joseph John , Lynch Brian Maurice
Published: April 2009

Conjoint use of pmr allylic coupling constants and of 1 3C nmr chemical shift patterns defines the predominant tautomeric form of 3‐methyl‐1‐phenylpyrazoline‐5‐thione in solution in aprotic dipolar and in non‐polar solvents as the thiol species, 3‐methyl‐1‐phenylpyrazole‐5‐thiol. The tautomeric preference thus differs from that of the oxygen analog, and is opposite to that noted for thiol‐thione tautomerism in six‐membered heteroaromatic species.
Cation radicals. XXVIII. Isolation and some reactions of dibenzodioxin cation radical perchlorate
Authors: Shine Henry J. , Shade Lewis R.
Published: April 2009

Preparation and isolation of dibenzodioxin cation radical perchlorate (2) by oxidation of dibenzodioxin in ethyl acetate‐lithium perchlorate at a platinum anode has been achieved. Reasonably pure 2 in amounts of 150–200 mg. were obtained reliably and reproducibly. Reaction of 2 with both nitrite and nitrate ions gave 2‐nitrodibenzodioxin (3). Reaction of 2 with pyridine gave N‐(2‐dibenzodioxinyl)pyridinium perchlorate (4). Reaction with water gave, as anticipated, the stoichiometric amount of dibenzodioxin. Reaction with ammonia, propylamine, t‐butylamine, and cyanide ion also gave dibenzodioxin with no evidence that nucleophilic substitution had occurred. It is believed that the formation of 3 and 4 represent the first examples of nucleophilic substitution into dibenzodioxin via its cation radical.
1.6‐Naphathyridines II. 2,3‐Distributed derivatives and some new tricyclic ring systems
Authors: Hawes Edwared M. , Gorecki Dennis K. J.
Published: April 2009

A number of new 2‐ and/or 3‐substituted 1,6‐naphthyridines were prepared via Friedländer reactiona with 4‐aminonicotinaldehyde and methylene compounds containing α‐ketones, Methylene compounds with two reactive α‐centers were also used. The facile conversion of the 1,6‐naphthyridines into new tricylic ring system is reported.
The synthesis and properties of pyridazino[4,3‐e] ‐as‐triazines and pyridazino[4,5‐e] ‐as‐triazines, two novel condensed pyridazine ring systems
Authors: Chesney Dennis K. , Castle Raymond N.
Published: April 2009

The compounds prepared in the novel pyridazino[4,3‐e]‐as‐triazine ring system are: 8‐chloro‐4‐methyl‐3,4‐dihydropyridazino[4,3‐e]‐as‐triazine (21), 8‐chloro‐2,4‐dimethyl‐3,4‐dihydropyridazino[4,3‐e]‐as‐triazine (23), 8‐chloro‐2‐ethyl‐4‐methyl‐3,4‐dihydropyridazino[4,3‐e]‐as‐ triazine (24), 4‐methyl‐3,4‐dihydropyridazino[4,3‐e]‐as‐triazine‐8‐thione (25), 4‐methyl‐3,4‐dihydropyridazino[4,3‐e]‐as‐triazine (26), 2,4‐dimethyl‐3,4‐dihydropyridazino[4,3‐e]‐as‐triazine (27), and 2‐ethyl‐4‐methyl‐3,4‐dihydropyridazino[4,3‐e]‐as‐triazine (28). In the novel pyridazino[4,5‐e]‐as‐triazine ring system the following compounds were prepared: 1,2‐dihydropyridazino[4,5‐e]‐as‐triazine (31), 3‐methyl‐1,2‐dihydropyridazino[4,5‐e]‐as‐triazine (32), 3‐ethyl‐1,2‐dihydropyridazino[4,5‐e]‐as‐triazine (33), and 1‐methyl‐1,2‐dihydropyridazino[4,5‐e]‐as‐triazine (35). The preparation of a number of previously unreported intermediates and compounds for structure proof are also described.
Chemistry of thienopyridines. XVII. Direct halogenation of thieno[2,3‐b]pyridine
Authors: Klemm L. H. , Merrill R. E. , Lee F. H. W. , Klopfenstein C. E.
Published: April 2009

Thieno [2,3‐b] pyridine (Ia) was converted into its 3‐chloro, 3‐bromo, and 3‐iodo derivatives by means of elemental halogen, silver sulfate, and sulfuric acid. Bromine in a buffered chloroform solution of la also gave the 3‐bromo compound (57% yield). Chlorine plus a refluxing mixture of Ia, chloroform, and water produced both the 3‐chloro and the 2,3‐dichloro derivatives. Various transformation products of these halothienopyridines (including the 2‐nitro‐3‐halo compounds) are described and mass spectral fragmentation patterns are presented.
The use of the wittig reaction in the modification of purine nucleosides
Authors: Montgomery John A. , Laseter Anne G. , Hewson Kathleen
Published: April 2009

The Pfitzner‐Moffatt oxidation of 6‐chloro‐9‐(2,3‐O‐isopropylidene‐β‐D‐ribofuranosyl)purine, 9‐(2,3‐O‐isopropylidene‐β‐D‐ribofuranosyl)‐6‐(methylthio)purine, and 2′,3′‐O‐isopropylideneadenosine gave the corresponding 5′‐aldehydes (3, 13, and 4), which were allowed to react with a number of Wittig ylids. The resulting olefins, primarilytrans, were reduced either catalytically or with diimide before removal of the 2′,3′‐O‐isopropylidene groups to give the desired 5′‐substituted purine ribonucleosides.
The reaction between 3,3‐bis(methoxyphenyl)‐3H‐naphtho[2,1‐b]pyran and 1,3‐bis(methoxyphenyl)‐1H‐naphtho[2,1‐b]pyran, 2,2‐diphenyl‐2H‐chromen and 2,4‐diphenyl‐4H‐chromen, and related compounds
Authors: Cotterill W. David , Iqbal Muhammad , Livingstone Robert , Walshaw Maurice V.
Published: April 2009

The reaction between 3,3‐bis(methoxyphenyl)‐3H‐naphtho[2,1‐b]pyran and 1,3‐bis(methoxyphenyl)‐1H‐naphtho[2,1‐b]pyran under acid conditions gives a 7a,15a‐dihydro‐7a,15‐bis(methoxyphenyl)‐16‐[2,2‐bis(methoxyphenyl)‐l‐vinyl]dinaphtho‐[2,1‐b:2,1‐g]‐4H,5H‐pyrano[2,3‐b]‐pyran.
Electron impact fragmentation of some tetramethyl derivatives of thiathrene and phenoxathiin
Authors: Saint‐Ruf G. , Servoin‐Sidoine J. , Coic J. P.
Published: April 2009

Mass spectra of thiathrene and three tetramethylthiathrenes (II), (III) and (IV) are reported and discussed. The principal mode of fragmentation of these compounds consists of the loss of sulphur to give the corresponding dibenzothiophene ion. The general pattern of electronolytic decomposition among the tetramethylthianthrenes is, however, much more complex. The mass spectrum of 2,3,7,8‐tetramethylphenoxathiin (VI) is also reported and compared with the spectrum of the corresponding thianthrene derivatives.
Ene syntheses in the s‐triazine series
Authors: Bessière‐Chrétien Y. , Serne H.
Published: April 2009

β‐Oxo‐s‐triazines undergo an ene synthesis with dienophiles. The ease of the reaction depends on the substituents of the triazine ring and on the nature of the enophile.
Kinetic studies of nucleophilic substitution of various halothiadiazoles with methoxide ion
Authors: Modarai B. , Ghandehari M. H. , Massoumi H. , Shafiee A. , Lalezari I. , Badali A.
Published: April 2009

A number of halo‐substituted 1,2,3 and 1,3,4‐thiadiozoles have been prepared, their reactivity towards methoxide ion have been studied and the kinetic parameters are reported.
Investigation of the grewe codeine method. Attempts to achieve a practical synthesis
Authors: Degraw J. I. , Christensen J. C. , Brown V. H. , Cory M. J.
Published: April 2009

The svnthesis of 1‐(2′‐bromo‐4′‐methoxy‐5‐hydroxybenzyl)‐6‐keto‐Δ4a‐5‐decahydroisoquinoline (IX) is described. Efforts to cyclize this intermediate or its N‐acyl derivatives in acidic media to morphinan products were unsuccessful. The presence of the para‐bromine blocking group apparently exerts a deactivating influence on the phenolic ring. 1‐(3′,5′‐Dihydroxy‐4′‐methoxybenzyl)‐6‐methoxy‐1,2,3,4,5,8‐hexahydroisoquinoline (XVIII) was readily cyclized to 2‐hydroxydihydronorthebainone. However, attempts to remove the 2‐hydroxy group and subsequent conversion to dihydronorcodeine were unrewarding.
Investigation on the isomerization of 2‐amino‐3‐aziridino‐1,4‐naphthoquinones to benzo[g]quinoxalines
Authors: Casini Giovanni , Claudi Francesco , Grifantini Mario , Martelli Sante
Published: April 2009

The course of the hydriodic acid‐catalysed and iodide‐catalysed isomerization of various 2‐amino‐3‐substituted‐aziridino‐1,4‐naphthoquinones (I) to 1,2,3,4,5,10‐hexahydrobenzo[g]‐quinoxaline‐5,10‐diones (III) is investigated, and steric aspects of the reaction are also considered. Only in the case of the phenylaziridino derivative (Ie) does hydriodic acid afford direct cyclization to the corresponding benzoquinoxalinedione (IIIe); in all other cases the hydriodides (V) of the cleavage products (II) are obtained, and liberation of the free bases (II) results in cyclization to the corresponding benzoquinoxalinediones (III) when the aziridine ring is monosubstituted or trans disubstituted, with retention of configuration in the latter case. In contrast, the free bases (II) obtained from cis disubstituted (I) are relatively stable and cyclize with excess iodide yielding trans disubstituted (III). Correspondingly, monosubstituted and trans disubstituted I undergo iodide‐catalysed isomerization to III whereas cis disubstituted I do not react.
Some 5,6‐dihydro‐4H‐pyrrolo[3,2,1‐i,j]quinolines
Authors: Steak Edgar A. , Fletcher Lynn T. , Carabateas Clarissa D.
Published: April 2009

On the basis of structural features which relate 5,6‐dihydro‐4H‐pyrrolo[3,2,1‐i,j]quinolines to indoles, several representative groups of derivatives were synthesized.
Elude de la réaction du β‐aminocrotonitrile et du α‐formyl phénylacétonitrile avec l'hydrazine: Synthèse d'amino‐7 pyrazolo[1,5‐a]pyrimidines
Authors: Alcalde Ermilas , De Mendoza Javier , Elguero José , Marino Juan , Garcia‐Marquina  , Almera Consuelo
Published: April 2009

The three compounds C8 H10N4 which arise from reaction of hydrazine and β‐aminocrotonitrile have been identified: the formation of anazine, a 3(5)‐amino 5(3)‐methyl pyrazole derivative and a 7‐amino pyrazolo [1,5‐a] pyrimidine has been demonstrated. The relationships among these compounds and with the methyl‐aminopyrazole have been studied.
Thiazolo [3,2‐b]‐s‐triazole
Authors: Tamur Yasumitsu , Hayashi Hironori , Sacki Eiko , Kim Joong‐Hyup , Ikeda Masazumi
Published: April 2009

2‐Formamidothiazole and O‐mesitylenesulfonylhydroxylamine readily gave 3‐umino‐2‐form‐amidothiazolium mesitylenesulfonate that with polyphosphoric acid gave thiazolo [3,2‐b]‐s‐triazole. triazole. In its nmr spectrum, a long‐range coupling of 1.4 Hz between H‐2 and H‐6 is observed.
The. Synthesis and chelation properties of N‐substituted amidrazones and related azines containing the 2‐pyridyl group
Authors: Case Francis H. , Schitt A. A. , Fang T. A.
Published: April 2009

The. preparation and properties of certain N‐substituted amidrazones from thioamides containing the 2‐pyridyl group and the azines derived from them by reaction with benzaldehyde and 2‐pyridinecarboxaldehyde is described.
Pyridazines. LXV. Reactions of some I‐phenacylazolopyridazinium halides with 2,3‐diphenylcyclopropenone, ‐thione, or hydrazine
Authors: Koren B. , Stanovnik B. , Tišler M.
Published: April 2009

I‐Phenacylazolopyridazinium bromides reacted with 2,3‐diphenylcyclopropenone or ‐thione in the presence of triethylaminc to give 3,4,6‐triphenyl‐2‐pyrone or ‐2‐thiopyrone and the corresponding azolopyridazine. Quaternized azolopyridazines reacted with hydrazine to give either 3,6‐diphenylpyridazine and the corresponding azoloazine or hy ring opening of the azine part to give 1‐methyl‐2‐(pyrazolyl‐5′)imidazole.
Reaction of ω‐cyanoacetophenone and some of its derivatives with secondary amines. New synthesis of aminopyridine derivatives
Authors: Purrello G. , Vullo A. Lo
Published: April 2009

ω‐Cyanoacetophenone (1a) and its derivatives 1b‐c react with morpholine (or piperidine) to give mainly 2,4‐diaryl‐3‐eyano‐6‐morpholino‐ (or piperidino‐) pyridine derivatives (5); relative β‐aminoeinnamonitriles 6 and very small amounts of amidines 4 are also obtained. When pyrrolidine is used compounds 5 cannot be detected and enamines 6 are the main product.

A mechanism involving the intermediate formation of enamines 6 (as electrophiles) and of carbanions 11 (as nucleophiles) is proposed to explain this new synthesis of aminopyridine derivatives.
Action of amines and carbonyl reagents on 3,5‐diphenyl‐4‐pyrone and its thio analogue
Authors: El‐Kholy Ibrahim El‐Sayed , Mishrikey Marcos Michael , Atmeh Ragheb Fuad
Published: April 2009

Several N‐substituted, 3,5‐diphenyl‐4‐pyridones and 4‐thiopyridones were obtained by the action of amines on 3,5,‐diphenyl‐4‐pyrone and its thio analogue. With hydrazine hydrate, the products were 1‐amino‐3,5‐diphenyl‐4‐pyridone and the corresponding thione. The spectral characteristics ol these pyridones were studied.
Novel polycyclic heterocycles. XII. Reactions of 1,2‐dihydro‐11‐(trifluoromethyl)‐3H‐7H‐quino[8, 1‐cd] [1,5]‐benzoxazepin‐3‐one with aromatic aldehydes
Authors: Yale Harry L. , Petigara Ramesh B.
Published: April 2009

The Claisen‐Schmidt condensation between 1,2‐dihydro‐11‐(trifluoromethyl)‐3H,7H‐quino‐[8,1 ‐cd][1,5]benzoxazepin‐3‐one, 1, and aromatic aldehydes has been investigated. The acid catalyzed reactions yielded the trans‐2‐benzylidene derivatives, 4; the structures and configurations of the group of compounds represented by 4 have been confirmed by pmr in conjunction with the Eu(fod)3 shift reagent. In contrast, catalysis with sodium hydroxide gave the isomeric 2‐benzyl‐endocyclic α,β‐unsaturated ketones, 3. Finally, the 4 could be isomerized to the corresponding 3 by means of sodium hydroxide. The ir, uv, and pmr spectra of these compounds are discussed.
New 2‐methyl‐6‐alkylamino‐5,8‐quinolinequinones and 1,2,3,4‐tetrahydro derivatives
Authors: Wan Yieh‐Ping , Porter Thomas H. , Folkers Karl
Published: April 2009

The syntheses of six new 2‐methyl‐6‐alkylamino‐5,8‐quinolinequinones, three 1,2,3,4‐tetrahydro‐5,8‐quinolinequinones, and 7‐(2′,6′,10′‐trimethylundecyl)‐6‐hydroxy‐5,8‐quinolinequinone are described as potential antimetabolites of coenzyme Q and as potential antimalarial agents. The six 2‐methyl‐6‐alkylamino‐5,8‐quinolinequinones were prepared by a six‐step synthesis. 2‐Methyl‐6‐methoxy‐8‐nitroquinoline was prepared from 2‐nitro‐4‐methoxyaniline and crotonaldehyde by a Skraup reaction. Raney nickel reduction gave 2‐methyl‐6‐metboxy‐8‐aminoquinoline, which upon diazotization followed by dithionite reduction yielded 2‐methyl‐6‐methoxy‐5,8‐diaminoquinoline. Subsequent dichromate oxidation gave 2‐methyl‐6‐methoxy‐5,8‐quinolinequinone, which yielded the corresponding 2‐methyl‐6‐alkylamino‐5,8‐quinolinequinone in good yield when treated with the appropriate alkylamine. The telrahydro‐5,8‐quinolinequinones were prepared by catalytic hydrogenation of the appropriate 5,8‐quinolinequinones at elevated H2 pressure followed by air oxidation of the reduction product. 7‐(2′,6′,10′‐Trimethylundecyl)‐6‐hydroxy‐5,8‐quinolinequinone was synthesized by radical alkylation of 6‐hydroxy‐5,8‐quinolinequinone by thermal decomposition of di‐3,7,11‐trimethyldodecanoyl peroxide, which was prepared by a multistep procedure from farnesol. Of the five new 2‐methyl‐6‐alkylamino‐5,8‐quinoline‐quinones tested against P. berghei in mice (blood schizonticidal test), only 2‐methyl‐6‐cycloheptylamino‐5,8‐quinolinequinone was active (T‐C = 6.1 at 320 mg./kg.). Both 7‐(2′,6′,10′‐trimelhytundecyl)‐6‐hydroxy‐5,8‐quinolinequinone and the tetrahydro derivatives were inactive in this same test system.
Heterocycles. CII. Barriers to rotation in some N′‐Heteroaryl N,N‐dimethylformamidines
Authors: Zupan M. , Pirc V. , Pollak A. , Stanovnik B. , Tišer M.
Published: April 2009

The free energies of activation about the =CHNMe2 bond in N′‐heteroaryl N,N‐dimethylformamidines have been found in the range from 15.6 kcal/mole to 23 kcal/mole.
Chemistry of thienopyridines. XIX. Further studies on chlorination and S‐oxidation in the thieno[2,3‐b] pyridine system
Authors: Klemm L. H. , Merrill K. K. , Lee F. H. W.
Published: April 2009

Treatment of thieno [2,3‐b] pyridine (1a) with chlorine gas in chloroform (plus water) gave a mixture of two 2,3‐dichloro‐2,3‐dihydrothieno[2,3‐b] pyridine 1‐oxides [trans‐syn (IIa), and cis‐anti (IIb)) [and 2,3,3‐trichloro‐2,3‐dihydrothieno[2,3‐b]pyridine syn‐1‐oxide (IVa), as well as a non‐isolated fourth product (prohably the anti isomer of IVa) and sometimes a small amount of thieno[2,3‐b]pyridine 1,1‐dioxide (III). Treatment of Ia in a solvent (water, chloroform‐water, or THF‐water) with sulfuric acid and sodium hypochlorite gave a mixture of IIb and III. Effects of variations of reaction conditions on the composition of the product mixture were ascertained through chemical isolation and/or pmr analysis. Products formed were rationalized in terms of the chlorine‐water‐hypochlorous acid equilibrium, plus attack of chlorine variously at positions 1 (S‐atom), 2, and 3 of 1a, but of hypochlorous acid only at position 1. Thermal and chromatographic limitations on isolation procedures for some of the products were established. Stereochemistries of IIa, IIb, and IVa were assigned by means of pmr spectrometry with the aid of the shift reagent Eu(fod)3. Spin‐spin couplings between the proton at position 2 and those at positions 4 and 6 were observed at high resolution.

In exploratory runs, 5‐ethyl‐la was converted into isolable 2,3‐dichloro‐5‐ethyl‐2,3‐dihydrothieno[2,3‐b]pyridine 1‐oxide, and 5‐acetyl‐Ia yielded 3‐chloro‐5‐acetylthieno] 2,3‐b]pyridine. Mass spectral fragmentation patterns for the various products are presented.
Synthesis and antimicrobial activity of 4‐aza‐5α‐sitostane and the 4‐methyl derivative
Authors: Aboul‐Enein Hassan Y. , Doorenbos Norman J.
Published: April 2009

Synthesis of 4‐aza‐5α‐sitostane (IX), and 4‐methyl‐4‐aza‐5α‐sitostane (XII) were accomplished through a set of reactions involving oxidative opening of ring A of α,β‐unsaturated ketone, ring closure, followed by catalytic hydrogenation and lithium aluminum hydride reduction, respectively. The antimicrobial activity for X and XII is reported.
Synthesis of 2‐[3′‐(trifluoromethyl)anilino] ‐5‐hydroxynicotinic acid
Authors: Němec Josef , Meeker Fred S. , Schreiber Eric C.
Published: April 2009

2‐[3′‐(Trifluoromethyl)anilino]‐5‐hydroxynicotinic acid(2)was synthesized by two routes: a) by direct hydroxylation of 2‐[3′‐(trifluoromethyl)anilino]nicotinie acid(1); and b) by the following sequence starting from 2‐chloro‐3‐methyl‐5‐nitropyridine(3)via5‐amino‐2‐chloro‐3‐methylpyridine(4), 2‐ehloro‐5‐hydroxy‐3‐methylpyridine(6), 5‐acetoxy‐2‐chloro‐3‐methylpyridine(7), 5‐acetoxy‐2‐chloronicotinie acid(8), and 2‐chloro‐5‐hydroxynicotinic acid(9).The correlation of2with one of the metabolites of1has been accomplished, and the identities of both compounds have been proven.
Acid catalyzed rearrangements of thia and aza analogs of adamantanes a new derivative of sulfamide, formaldehyde and ammonia
Authors: Thyagarajan B. S. , Kang J. B.
Published: April 2009

The conversion of 2‐thia‐1,3,5,7‐tetraazatricyclo[3.3.1.13,7] decane 2,2‐dioxide under acid conditions into a hexaazatetracyelo derivative is described.
Hydroxymethylphenylnaphthoie acid lactones
Authors: Ahmed Riaz , Holmes T. L. , Stevenson Robert
Published: April 2009

Reduction of 1‐phenylnaphthalene‐2,3‐dicarboxylic anhydride (I) with zinc and acetic acid or lithium aluminium hydride yields a mixture of 1‐phenyl‐3‐hydroxymethyl‐2‐naphthoie acid lactone (II) and 1‐phonyl‐2‐hydroxymethyl‐3‐naphthoie acid lactone (III). Catalytic hydrogenation of (I) gave the tetrahydronaphthalene dicarboxylic anhydride (IV). Oxidation of the phenyldihydronaphthofuran (X), prepared by base‐catalyzed cyclization of the ether (IX), also yielded lactones (II) and (III). The phenyltetrahydronaphthofuran (XII) was similarly prepared by cyclization of the phenylpropargyl cinnamyl ether (XI).
Synthesis of unsymmetrical 2,4‐dialkylpyrazolo[1,5‐a]‐1,3,5‐triazines
Authors: Novinson Thomas , Senga Keitaro , Kobe Jože , Robins Roland K. , O'Brien Darrell E. , Albert Anthony A.
Published: April 2009

The reaction of 3‐aminopyrazole with imidate esters such as ethyl acetimidate, gave N‐(pyrazol‐3‐yl)acetamidine (1) rather than the isomeric 2‐acetamidoyl‐3‐aminopyrazole. Ring closure of 1 with orthoesters such as ethyl propionimidate, afforded unsymmetrically substituted 2.4‐dialkylpyrazolo[1,5‐a]‐1,3,5‐triazines such as 4‐ethyl‐2‐methylpyrazolo[1,5‐a]‐1,3,5‐triazine (3). The structure of 1 was confirmed by several alternate syntheses. The unique feature of this two‐step synthetic approach to the synthesis of pyrazolo[1,5‐a]‐1,3,5‐triazines is that it is a convenient method of preparing fused triazines based on available pyrazoles rather than the less accessible dialkyltriazines.
Syntheses of 5H‐benzoxazolo[3,2‐a] quinolin‐5‐ones
Authors: Kim Dong Han , Fieber Richard A. , Santilli Arthur A. , Bell Stanley C.
Published: April 2009

Treatment of N‐(2‐hydroxyphenyl)anthranilic acid with acetic anhydride, under refluxing conditions provided a simple method for the synthesis of 5H‐henzoxazolo[3,2‐a] quinolin‐5‐one (IVa), a heretofore unreported ring system. When propionic anhydride was used in the above reaction, 6‐methyl‐5H‐benzoxazolo[3,2‐a]quinolin‐5‐one (Va) was obtained. Other examples prepared in this fashion were IVb, IVc and Vb. Treatment of IVa with methoxyethylamine afforded 1,2‐dihydro‐1‐(2‐hydroxyphenyl)‐2‐(methoxyethylimino)‐4‐quinolinol (VII). A possible mechanism for the cyclization reaction is discussed.
Synthesis of diimidazo[1,2‐a:2′,1′‐c]pyrazines and diimidazo[1,2‐a:2′,1′‐c] [1,4]diazepines
Authors: Melloni P. , Fusar‐Bassini D. , Dradi F. , Confalonieri C.
Published: April 2009

Two new heterocyclic compounds, diimidazo[1,2‐a:2′,1‐c]pyrazine and 5H‐diimidazo[1,2‐a: 2,1′‐c][1,4]diazepine have been synthesized by various routes from 2,2′‐biimidazole (1) (2) together with some hydro, hydroxy and alkyl derivatives.
A novel synthesis of a benzimidazo[1,2‐c]benzopyrimidine by photolysis of 4‐(benzotriazol‐1‐yl‐2‐phenylquinazoline
Authors: Hubert A. J.
Published: April 2009

A novel synthesis of 6‐phenylbenzimidazo[1,2‐c]benzopyrimidine (5) by photolysis of 4‐(benzolriazol‐1‐yl‐2‐phenylquinazoline (3) is described. The acid‐catalysed thermolysis of 3 leads to an extensive degradation yielding 2‐pbenyl‐4‐quinazolinone (4).
1,2,4‐Triazincs XIII. The bond lengths and bond angles of a 1,2,4‐triazine
Authors: Atwood J. L. , Krass D. K. , Paudler William W.
Published: April 2009

The bond distances and bond angles of 5‐(p‐chlorophenyl)‐1,2,4‐triazine determined by three dimensional X‐ray crystallographic analysis are reported. The pertinent bond lengths are N1N2, 1.335Å, N2‐C3, 1.314Å, C3N4, 1.339; N4‐C5, 1.317; C5‐C6, 1.401; C6N1, 1.317Å. A comparison of these bond distances with those of similar polyazabenzenes shows that the canonical structure of 1,2,4‐triazine with a N1N2 single bond more closely represents the ground state of this ring system, than the one with a N1N2 double bond.
1,2,4‐Triazino[4,3‐c]‐ and [2,3‐c]quinazolines
Authors: Trepanier Donald L. , Sunder Shyam , Braun Werner H.
Published: April 2009

This paper describes the reactions of 2‐o‐aminophenyl‐1,4,5,6‐tetrahydro‐1‐methyl‐1,2,4‐triazine with a variety of reagents to give substituted 1,2,4‐triazino[4,3‐c]quinazolines or 1,2,4‐triazino[2,3‐c]quinazolines. Certain representative compounds of these two new heterocyclic systems were characterized by the tlc, ir, nmr, mass spectra, and identified by unequivacol synthesis.
Polarography of some 2,1,3‐benzothiadiazoles, benzofurazans, 2,1,3‐benzoselenadiazoles, and 3,4‐disubstituted and fused 1,2,5‐thiadiazoles
Authors: Sherman E. O. , Lambert S. M. , Pilgram K.
Published: April 2009

The redox behavior has been determined in acetonitrile solutions at a mercury and platinum electrode for 2,1,3‐benzo(group VI)diazoles, and 3,4‐disubstituted and fused 1,2,5‐thiadiazoles. The derivatives studied contained alkyl, phenyl, bromo, chloro, cyano, nitro, methylsulfonyl, and trifluoromethylsulfonyl groups. All ring systems and their derivatives are reversibly reduced initially in a one‐electron step, to their respective radical anion, but the nitro and bromo derivatives are reduced preferentially at the substituent group. The potential at which the production of the radical anion occurred became more anodic as the electron withdrawing ability of the substituent and the number of substituents increased.
Hétérocyclisations intramoléculaires par réaction d'oxymercuration. I — synthèse et configurations des hétérocycles
Authors: Speziale V. , Roussel J. , Lattes A.
Published: April 2009

L'oxyrnercuration intramoléculaire cyelisante d'alcools γ‐δ éthyléniques a été réalisée afin d'en étudier la stéréochimie. Le rǒle de la nature du sel mercurique, de l'alcool et des conditions opératoires a été examiné. La réduction in situ des organomercuriques conduit parfois à des proportions de diastéréoisomères différentes de cellos obtenues à partir des produits isolés, qui ne subissent pas de changement de configurations au cours de cette étape.
Synthesis of 2,1,3‐benzothiadiazolecarbonitriles
Authors: Pilgram K. , Skiles R. D.
Published: April 2009

2,1,3‐Benzothiadiazolecarbonitriles, 2, have been prepared by two different methods. Reaction of bromo‐2,1,3‐benzothiadiazoles, 1, with cuprous cyanide occurs advantageously in refluxing dimethylformamide to give 2, complexed with curpous bromide. Hydrogen peroxide in hydrochloric acid at 30–40° is shown to be an effective reagent for efficient decomposition of these reactions complexes, 2 CuBr, and subsequent isolation of 2. Yields in the Sandmeyer method for preparing nitriles 2 were improved by diazotizing amino‐2,1,3‐benzothiadiazoles, 3, with nitrosyl‐sulfuric acid prior to reaction with the cuprous‐sodium cyanide complex.
Syntheses and properties of 3‐acylimino‐1‐alkylimidazolium and benzimidazolium betaines
Authors: Tamura Yasumitsu , Hayashi Hironori , Minamikawa Jun‐Ichi , Ikeda Masazumi
Published: April 2009

3‐Amino‐1‐alkylimidazolium and benzimidazolium mesitylenesulfonates were readily prepared in good to high yeilds by treating the parent heterocycles with O‐mesitylenesulfonylhydroxylamine. Treatment of the 3‐amine salts with acylating agents gave crystalline 3‐acylimines, which showed the characteristic ir, uv, nmr, and mass spectral properties. Deuterium exchange of the 3‐acylimines occurs at the 2‐position. Thermolysis of neat 3‐benzoylimino‐1‐rnethylbenzimidazolium betaine afforded 2‐benzamido‐1‐methylbenzimidazole and products derived from NN bond cleavage. Irradiation of 3‐benzoylimino‐1‐alkylbenzimidazoliurn betaines resulted in NN bond cleavage to give 1‐alkylbenzimidazoles and benzamide, while the corresponding 3‐ethoxycarbonylimines underwent rearrangement to afford ethyl 1‐alkyl‐2‐benzimidazolecarbamates.
The synthesis of 7‐(substituted‐amino)‐3‐azabicyclo[3.2.0] heptanes
Authors: Rynbrandt Ronald H.
Published: April 2009

1,2‐Cycloaddition reactions of several enamines with N‐substituted maleimides and 4‐phenyl‐1,2,4‐triazoline‐3,5‐dione have been carried out. The adducts were transformed into 7‐(substituted‐amino)‐3‐azabicyclo[3.2.0]heptanes and a 1,2,4‐triazolidine‐1‐acetaldehyde, respectively. These are the first reported examples of 3‐azabicyclo[3.2.0]heptanes substituted in any position other than the 3‐position. The reaction of an ynamine with N‐benzylmaleimide afforded a bicyclic intermediate which upon hydrolysis gave a 2,5‐dioxo‐3‐pyrrolidineacetic acid.
Novel polycyclic heterocyeles. XIII. Derivatives of the oxime and carbinol derived from 1,2‐dihydro‐11‐(trifluoromethyl)‐3H,7H‐quino[8,1‐cd] [1,5]benzoxazepin‐3‐one
Authors: Yale Harry L. , Petigara Ramesh B.
Published: April 2009

The anions derived from the oxime, 2, and the carbinol, 3, generated by reaction with sodium hydride, were reacted with aminoalkyl chlorides and an aroyl chloride to give a number of amino‐alkyl ethers and an aroyl ester. In addition, 2 and 3 were reacted with phenylisocyanate to yield O‐phenylcarbamoyl derivatives. The pmr spectra of several of these compounds are discussed.
Synthesis of fused hydantoins by intramolecular amidoalkylation
Authors: Zaugg H. E. , Arendsen D. L.
Published: April 2009

Several 1‐(2‐arylcthyl)hydantoins 2 have been cyclized through their 5‐bromo derivatives. The hydantoins 2a and 2b, unsubstituted in the 5‐posilion, require stannic chloride catalysis of the cyclization to 3a and 3b, respectively. However, the 5‐phenyl analog 2c (n = 2) cyclizes spontaneously and essentially quantitatively to 5 during bromination. This reaction is limited to the formation of a 6‐membered ring.
Synthesis and structural assignment of 5,6‐dihydro‐8‐hydroxy‐9‐methoxy‐1H,7H‐benzo[ij] quinolizine‐1,7‐dione
Authors: Wright George C. , Schwan Thomas J. , Miles Nelson J.
Published: April 2009

The compound 5,6‐dihydro‐8‐hydroxy‐9‐methoxy‐1H,7H‐benzo[ij]quinolizine‐1,7‐dione ( 4a) was synthesized from 3‐(1,4‐dihydro‐6,7‐dimethoxy‐4‐oxo‐1‐quinolyl)propionic acid (3a, free base), involving spontaneous demethylation with ring closure. The structural assignment of 4a was based on an analogous, unequivocal synthesis of 5,6‐dihydro‐9‐ethoxy‐8‐hydroxy‐1H,7H‐benzo[ij]quinolizine‐1,7‐dione hydrochloride (4b).
Benzomorphan analogues: Synthesis of some thieno[2,3‐f] morphans
Authors: Montzka Thomas A. , Matiskella John D.
Published: April 2009

A series ofN‐substituted 5,9‐dimethylthieno[2,3‐f]morphans and 5‐phenylthieno[2,3‐f] ‐ morphans has been prepared starting from 3,4‐dimethylpyridine and 4‐phenylpyridine and 3‐thenylbromide by an application of the Grewe morphinan synthesis. The thieno [2,3‐f]morphans were tested for analgetic activity, but only weak analgetic activity relative to toxicity and no morphine antagonism activity was observed.
Pyrido[1,2‐b] indazole and its derivatives
Authors: Abramovitch R. A. , Kalinowski J.
Published: April 2009

A new route to pyrido[1,2‐b]indazole and its derivatives is described and the nitration of the parent compound is reported. The formation of δ‐carbolines as byproducts is discussed.
The synthesis of certain 8‐cyano‐2,4‐disubstituted‐imidazo[1,5‐a] pyrimidines
Authors: Novinson Thomas , O'Brien Darrell E. , Robins Roland K.
Published: April 2009

A number of imidazo[1,5‐a]pyrimidine‐8‐carboxamides were synthesized by reacting various β‐dicarbonyl compounds with 5(4)‐aminoimidazole‐4(5)carboxamide (AICA,1), the non‐ribosylated form of AICAR, a key intermediate in the metabolic pathway of purine biosynthesis. Cyclization of1with ethylacetoacetate yielded 2‐methylimidazo[1,5‐a]pyrimidin‐1H‐4‐one‐8‐carboxamide (2). The treatment of2with phosphorus oxychloride gave 4‐chloro‐8‐cyano‐2‐methylimidazo[1,5‐a]pyrimidine (3). Various nucleophiles displaced the 4‐chloro substituent of3under mild conditions. However, the 4‐methylthio group of 8‐cyano‐2‐methyl‐4‐methylthioimidazo[1,5‐a)pyrimidine (8a) was also displaced under very mild conditions. Even more strangely, the 4‐diethylamino group of 8‐cyano‐4‐diethylamino‐2‐methylimidazo[1,5‐a]pyrimidine (5a) was displaced by ammonia to give 4‐amino‐8‐cyano‐2‐methylimidazo[1,5‐a]pyrimidine (7).
Photochemical functionalization of 6‐azauracils to 5‐substituted‐6‐azauracils
Authors: Swenton John S. , Balchunis Robert J.
Published: April 2009

Photochemical cycloaddition of 6‐azauracil derivatives to enol acetates yields hydrolytically labile bicyclic azetidines which decompose in good to excellent yield to 5‐substituted‐5,6‐dihydro‐6‐azauracils. These compounds can in turn be oxidized by bromine to the 5‐substituted‐6‐azauracil. This reaction sequence has also been applied to 2′,3′,5′‐tri‐o‐benzoyl‐6‐azauridine resulting in a 60% overall yield of the functionalized nucleoside derivative. The three‐step procedure reported here affords a simple method for carboncarbon bond formation at the 5‐position of 6‐azauracil and may be applicable to other imines systems.
Synthesis of hexahydro 1,3,5‐triCarbalkoxy‐s‐triazines, octahydro‐1,3,5,7‐tetracarbalkoxy tetrazocines and their interconvertibility
Authors: Thyagarajan B. S. , Majumdar K. C.
Published: April 2009

The condensations of urethanes with formaldehyde under appropriate experimental conditions affords either 1,3,5‐triazines or 1,3,5,7‐tetrazoeines. The two systems are interconvertible under acid catalysis.
Pentaatomie heteroaromatic cations. Note III . A Convenient Synthesis of Aldehydes from Carboxylic Acids via 2‐Substituted 1,3‐Benzoxathiolium Perchlorates
Authors: Costa Luigi , Degani Iacopo , Fochi Rita , Tundo Piero
Published: April 2009

A convenient method for the preparation of aldehydes from the corresponding carboxylic acids is presented. By reaction of the carboxylic acids with o‐mercaptophenol and perchloric acid in phosphorus oxychloride, the corresponding 2‐substituted 1,3‐benzoxathiolium perehlorates were obtained. Reduction of the salts with lithium aluminium hydride in dry ether gave 2‐substituted 1,3‐benzoxathioles, which, when hydrolyzed by mercuric chloride, gave the corresponding aldehydes. Twenty five aldehydes of different structure were obtained in good yields, by a fast and simple procedure.
Potential ambifunctionality of 2‐azidopyrido[1,2‐a] pyrimidin‐4‐one
Authors: Kovačič M. , Polanc S. , Stanovnik B. , Tišler M.
Published: April 2009

2‐Azidopyrido[1,2‐a]pyrimidin‐4‐one can exit only in the azido form and undergoes cyclo‐addition reaction with 1,3‐dicarbonyl compounds to form 1,2,3‐triazole derivatives. Under the influence of bases or hydrochloric acid the carbonyl group is attacked with subsequent opening of the pyrimidine ring. This causes an immediate cyclization of the azide group to give a tetrazolo derivative. In a similar way a triazole ring can be formed from the appropriate hydrazino derivatives of pyrido[1,2‐a]pyrimidin‐4‐one.