bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of 2‐(2′,3′‐dihydroxypropyl)‐5‐amino‐2H‐1,2,4‐thiadiazol‐3‐one and 3‐(2′,3′‐dihydroxypropyl)‐5‐amino‐3H‐1,3,4‐thiadiazol‐2‐one
Authors: Párkányi Cyril , Yuan Hui Liang , Cho Nam Sook , Jaw Jin‐Hwa J. , Woodhouse Tamar E. , Aung Thomas L.
Published: March 2009

The synthesis of two new acyclic nucleoside analogs, 2‐(2′,3′‐dihydroxypropyl)‐5‐amino‐2H‐1,2,4‐thiadiazol‐3‐one (1) and 3‐(2′,3′‐dihydroxypropyl)‐5‐amino‐3H‐1,3,4‐thiadiazol‐2‐one (2), is reported. The first compound, 1, was obtained by reaction of 3‐chloro‐1,2‐propanediol with the sodium salt of 5‐amino‐2H‐1,2,4‐thiadiazol‐3‐one (3) in anhydrous dimethylformamide. Similarly, 5‐amino‐3H‐1,3,4‐thiadiazol‐2‐one (4) reacted with 3‐chloro‐1,2‐propanediol to give 2. The thiadiazole 4 was prepared by condensation‐cyclization of hydrazothiodicarbonamide (9).
Heterocyclic compounds from 2‐(alkoxycarbonylcyanomethylene)‐1,3‐dioxolanes
Authors: Neidlein Richard , Kikelj Danijel , Kramer Walter
Published: March 2009

2‐(Alkoxycarbonylcyanomethylene)‐1,3‐dioxolanes reacted with hydrazines and hydroxylamine to yield 1‐substituted 4‐alkoxycarbonyl‐5‐amino‐3‐(2′‐hydroxyethoxy)pyrazoles and 4‐alkoxycarbonyl‐5‐amino‐3‐(2′‐hydroxyethoxy)isoxazoles respectively. With guanidine and benzamidine 2‐substituted (R = NH2, C6H5) 5‐cyano‐6‐(2′‐hydroxyethoxy)pyrimidin‐4‐ones were obtained. Reaction of 2‐(cyanomethoxycarbonylmethylene)‐1,3‐dioxolane with 1,3‐diaminopropane afforded 2‐(cyanomethoxycarbonylmethylene)‐1,3‐hexahydro‐pyrimidine whereas treatment of the same compound with 4,5‐dimethyl‐1,2‐phenylenediamine gave 2‐(cyanomethoxycarbonylmethylene)‐5,6‐benzimidazoline. The structures of pyrazoles and pyrimidones were assigned on the basis of 1H‐{1H} and 13C‐{1H}‐nOe experiments.
Unsymmetrically substituted furoxans. Part 11. Methylfuroxancarbaldehydes
Authors: Fruttero Roberta , Ferrarotti Bruno , Serafino Anna , Di Stilo Antonella , Gasco Alberto
Published: March 2009

The two isomeric 3‐methyl‐4‐furoxancarbaldehydes (2a) and 4‐methyl‐3‐furoxancarbaldehyde (2b) have been prepared. Discussion of their structures, thermal equilibration and kinetic of thermal conversion from the 3‐methyl to the 4‐methyl isomer are also reported. (Phenylsulfonyl)hydrazones 3a and 3b have been prepared as derivatives in view of their potential antitumoral properties.
Synthesis of new benzopyrans related to podophyllotoxin
Authors: Jurd Leonard
Published: March 2009

Mannich bases of types 1 or 8, which are readily synthesized by condensation of 3,4‐methylenedioxyphenol with aromatic aldehydes and pyrrolidine or piperazine, react with cyclic and acyclic β‐diketones to yield benzopyrans. These benzopyrans are structurally similar to podophyllotoxin and like this drug some of the benzopyrans show in vivo anti‐leukemic action in mice.
Heterocyclic ring‐analogs of dihydropyridine calcium antagonists
Authors: Taylor Michael D. , Anderson Kevin R. , Badger Edward W.
Published: March 2009

An improved synthesis of the 1,4‐dihydropyrazine derivative, 3, is described that involves the versatile 1,4‐diketointermediate,9. This intermediate was converted to several heterocyclic ring‐analogs of 1,4‐dihydropyridine in addition to 3 including derivatives of pyrrole and furan.
Study of the structure of besulpamide, 1‐[(4‐chloro‐3‐sulfamoylbenzoyl)amino]2,4,6‐trimethylpyridinium hydroxide inner salt, and related compounds, using X‐Ray crystallography and 1H and 13C nuclear magnetic resonance spectroscopy
Authors: Frigola Jordi
Published: March 2009

The diuretic and antihypertensive drug Besulpamide, 1‐[(4‐Chloro‐3‐sulfamoylbenzoyl)amino]‐2,4,6‐trimethylpyridinium hydroxide inner salt, and related compounds have been investigated by nmr spectroscopy and mass spectrometry. A mechanism for the formation of the salt 5 is proposed. The tautomerism of hydroxy derivatives of Besulpamide is discussed on the basis of nmr spectroscopy. The single‐crystal X‐ray investigation of Besulpamide, R = 0.038 (Rw = 0.041), showed two crystallographically independent molecular conformations in the crystal structure, space group P\documentclass{article}\pagestyle{empty}\begin{document}$\bar 1$\end{document}, a = 8.485(3), b = 14.282(2), c = 15.312(6), α = 69.41(2), β = 82.22(4), γ = 72.78(3).
Chemical behaviour of N‐(2‐hydroxybenzyl)anthranilic acids in the presence of acyclic anhydrides
Authors: Aversa M. C. , Bonaccorsi P. , Giannetto P.
Published: March 2009

The synthesis of 11‐acyl‐11,12‐dihydrodibenz[bf][1,5]oxazocin‐6‐ones 9‐13 is reported by reaction of N‐(2‐hydroxybenzyl)anthranilic acids 1 with acetic, isobutyric, 2‐ethylbutyric anhydrides. The structures of the obtained 6,8,6 products are proved with the use of ir, mass spectrometry, 1H and 13C nmr spectra, homo‐and heteronuclear two‐dimensional nmr experiments. The formation of 9‐13 is discussed in relation to the obtainment of 12H‐quino[2,1‐b][1,3]benzoxazin‐5‐ones 2‐8 and 6a,12‐dihydro[3,1]benzoxazino[2,1‐b][1,3]‐benzoxazin‐5‐ones 14‐19 from the same starting products 1 with suitable anhydrides under controlled reaction conditions.
Methods for controlling the regioselection in the reaction of 3‐amino‐5‐benzylthio‐1,2,4‐triazole with acetylacetaldehyde dimethyl acetal
Authors: Monte William T. , Kleschick William A. , Meikle Richard W. , Snider Sigrid W. , Bordner Jon
Published: March 2009

The reaction of 3‐amino‐5‐benzylthio‐1,2,4‐triazole with acetylacetaldehyde dimethyl acetal affords 2‐benzylthio‐5‐methyl‐1,2,4‐triazolo[1,5a]pyrimidine or 2‐benzylthio‐7‐methyl‐1,2,4‐triazolo[1,5a]pyrimidine regioselectively depending on the reaction conditions.
8,11 a‐methanocycloocta[d,e]quinazolines: Diisophoranes incorporating the pyrimidine ring system
Authors: Kurzer Frederick , Langer Stanley S.
Published: March 2009

The interaction of 1‐chloro(or hydroxy)diisophor‐2(7)‐en‐3‐one 1 or 3 with guanidines or ureas produces good yields of substituted 8,11a‐methanocycloocta[d,e]quinazolines 5‐11, involving a nucleophilic SN1‐substitution at the 1‐bridgehead and dehydrative cyclisation at the 3‐keto‐group of the tricyclic reactants 1, 3. The structure assigned to members of this novel heterocyclic bridged ring‐system is based on both chemical and carbon nmr spectral evidence. The synthesis provides further variants of the incorporation of a fused heterocyclic ring into the tricyclo[7.3.1.02,7]tridecane carbon skeleton. A related condensed [1,3]oxazine 16 is similarly accessible.
A simple crab‐like cyclization procedure to prepare polyaza‐crowns and cyclams with one or two unsubstituted macroring nitrogen atoms or with a hydroxy group
Authors: Bradshaw Jerald S. , Krakowiak Krzysztof E. , Izatt Reed M.
Published: March 2009

A simple and convenient method to prepare polyaza‐crowns and cyclams containing one or two unsubstituted macroring nitrogen atoms or a hydroxy group is described. The process involves the reaction of a bis‐ chloroamide with a bis‐secondary amine followed by reduction of the cyclic diamide. The bis‐chloroamide resembles a crab with two reactive organochloride groups poised and ready to react, hence the term “crab‐like” cyclization. Nine new polyaza‐crowns and cyclams were prepared.
The oxidative‐rearrangement of 1‐amino‐2‐indolinones. A synthesis of 2‐substituted‐3(2H)‐cinnolinones
Authors: Zey R. L. , Richter G. , Randa H.
Published: March 2009

Several 2‐substituted‐3(2H)‐cinnolinones have been synthesized by a ring expansion of the respective 1‐substituted‐2‐indolinones via an oxidative‐rearrangement with t‐butyl hypochlorite.
Anticancer anilinoacridines. A process synthesis of the disubstituted amsacrine analog CI‐921
Authors: Brennan Sean T. , Colbry Norman L. , Leeds Robert L. , Leja Boguslawa , Priebe Stephen R. , Reily Michael D. , Showalter H. D. Hollis , Uhlendorf Susan E. , Atwell Graham J. , Denny William A.
Published: March 2009

An improved process for the synthesis of bulk quantities of the clinical amsacrine analog CI‐921 is reported. Described also are detailed analytical and spectroscopic data for this agent.
meso‐tetrakis[2.2]paracyclophanylporphyrin: Electronic structure and electrochemical behavior
Authors: Czuchajowski Leszek , Goszczynski Stefan , Wisor Antoni K. , Bennett Janet E. , Malinski Tadeusz
Published: March 2009

Replacement of all phenyl groups in meso‐tetraphenylporphyrin, TPP, by [2.2]paracyclophane, PCP, enhances the increase of energy of the HOMO and HOMO‐1 of porphine, P, already noticed for the mono‐[2.2]paracyclophanyl‐substituted TPP, and fills the energy gap by the occupied MOs of the PCP units. The first oxidation half‐wave potential is respectively decreased to 0.52 V. The CNDO/S‐CIS calculations agree with the experimental bathochromic shifts of all bands in the electronic spectra of the considered atropoisomers of the title compound, TPCPP, as compared to TPP. In the excited B states the interactions between the PCP and porphine units are represented mainly by the charge transfer of 0.44 e from PCP to P, according to transition density matrix calculations. While electroreduction of the title compound results in a successive formation of the anion radical and dianion, oxidation represents a four‐step process involving one electron transfer per step, and resulting in the oxidation of two PCP units. Formation of the conductive polymeric film on the electrode seems to be connected with the transient formation of a quinoid system of bonds.
Regioselection in the reaction of 3‐amino‐5‐benzylthio‐1,2,4‐triazole with unsymmetrical 1,3‐diketones
Authors: Kleschick William A. , Bordner Jon
Published: March 2009

The results of a study of the regioselection in the reaction of 3‐amino‐5‐benzylthio‐1,2,4‐triazole with several unsymmetrical 1,3‐diketones are reported. The 1,3‐diketones studied are 1,1,1‐trifluoro‐2,4‐pentanedione, benzoylacetone and 2‐acetylcyclopentanone. Chemical, spectroscopic and X‐ray crystallographic data are presented to support structural assignments of the major reaction products.
An improved synthesis and refined crystal structure of 1‐methyluracil
Authors: Micklitz Wolfgang , Lippert Bernhard , Schöllhorn Helmut , Thewalt Ulf
Published: March 2009

A modification of a previously reported synthesis of 1‐methyluracil which simplifies the isolation of the compound is reported together with a refined X‐ray analysis of the title compound.
Synthesis and biological properties of 3‐methyl‐10‐propargyl‐5,8‐dideazafolic acid
Authors: Jones Terence R. , Betteridge Richard F. , Newell David R. , Jackman Ann L.
Published: March 2009

The synthesis of N3‐methyl‐10‐propargyl‐5,8‐dideazafolic acid (1b) is described. Ring closure of methyl‐5‐methylanthranilate with chloroformamidine hydrochloride gave a high yield of pure 2‐amino‐4‐hydroxy‐6‐methylquinazoline treatment of which with iodomethane/sodium hydroxide provided the corresponding 3‐methylquinazoline (6) which was converted to its 2‐pivaloylamino derivative. This synthetic approach, next involving functionalisation of the 6‐methyl group, was not further pursued because of difficulty encountered in removing the pivaloyl group. Methyl 5‐methylanthranilate was treated with p‐toluenesulfonyl chloride and the product then N‐methylated. The tosyl group was cleaved with hydrogen bromide/phenol and the resulting methylamine ring‐closed with chloroformamidine hydrochloride to provide 2‐amino‐1,4‐dihydro‐1,6‐dimethyl‐4‐oxoquinazoline (11). The 2‐pivaloylamino derivative of 11 was prone to hydrolytic deamination when attempts were made to remove the pivaloyl group and further elaboration of this heterocycle, with the intention of obtaining N1‐methyl‐10‐propargyl‐5,8‐dideazafolic acid was, too, not attempted. Di‐t‐butyl N‐(4‐propargylamino)benzoyl)‐L‐glutamate was therefore prepared and coupled with 2‐amino‐6‐bromomethyl‐4‐hydroxyquinazoline hydrobromide. The resulting antifolate diester was N‐monomethylated. Removal of the t‐butyl groups with trifluoracetic acid afforded the target compound 1b and its structure was proved by degradation to the quinazoline 6. Its IC50 for L1210 thymidylate synthase (TS) was 26 μM; the control value for 10‐propargyl‐5,8‐dideazafolic acid (1a) was 0.02 μM. Thus the substitution of the lactam hydrogen in 1a by a methyl group reduced the TS inhibition by 1300‐fold. Compound 1b was poorly cytotoxic to L1210 cells in culture (ID50 > 100 μM). An unperturbed lactam group in this class of antifolate is important for binding to TS.
The synthesis of 5,8‐difluoronaphtho[2,3‐c]thiophene‐4,9‐dione and its facile conversion to 2‐[2‐(dimethylamino)ethyl]‐ 5‐[2‐(dimethylamino)ethylamino]‐8‐fluoro‐naphtho[2,3‐c] pyrrole‐4,9‐dione
Authors: Krapcho A. Paul , Petry Mary E.
Published: March 2009

The synthesis of 5,8‐difluoronaphtho[2,3‐c]thiophene‐4,9‐dione (2a) has been accomplished. Treatment of 2a with 2,2‐dimethylaminoethylamine leads to 2‐[2‐(dimethylamino)ethyl]‐5‐[2‐(dimethylamino)ethylamino]‐8‐fluoronaphtho[2,3‐c]pyrrole‐4,9‐dione (6).
A convenient synthesis of novel pyridazino[3,4‐b]quinoxaline and pyrazolo[3,4‐b]quinoxaline utilizing 1,3‐dipolar cycloaddition reaction
Authors: Kim Ho Sik , Kurasawa Yoshihisa , Takada Atsushi
Published: March 2009

The reaction of 2,6‐dichloroquinoxaline 4‐oxide 4 with methylhydrazine gave 6‐chloro‐2‐(1‐methylhydrazino)quinoxaline 4‐oxide 5, whose reaction with dimethyl acetylenedicarboxylate or 2‐chloroacrylonitrile resulted in the 1,3‐dipolar cycloaddition reaction to afford 7‐chloro‐3,4‐bismethoxycarbonyl‐1‐methyl‐1,2‐dihydropyridazino[3,4‐b]quinoxaline 6 or 6‐chloro‐3‐hydroxymethylene‐1‐methyl‐2,3‐dihydro‐1H‐pyrazolo[3,4‐b] quinoxaline hydrochloride 7, respectively.
One‐step syntheses of macrocyclic compounds: A short review
Authors: Krakowiak Krzysztof E. , Izatt Reed M. , Bradshaw Jerald S.
Published: March 2009

Macrocyclic ligands have been prepared by various one‐step cyclooligomerization processes. This short review covers one‐step cyclization reactions involving the formation of four to twenty or more new covalent bonds. The new macrocycles reviewed include cyclophanes, biscrown ethers, cryptands, macrolides, cage compounds, calixarenes, homocalixarenes, cucubiturils, and supercryptands all prepared by one‐step syntheses.
Nucleophilic substitution and electron transfer in the ring‐opening reactions of β‐lactones: A short review
Authors: Jedlinński Zbigniew
Published: March 2009

Nucoleaophilic substitution by activated organic anions and single and two electron transfer in ring opening reactions of 4‐membered β‐lactones are described.
Sonochemical reformatsky reactions of α‐bromoesters with sym‐(keto)dibenzo‐16‐crown‐5
Authors: Ross Nathan A. , Bartsch Richard A.
Published: March 2009

Reactions of sym‐(keto)dibenzo‐16‐crown‐5 with ethyl α‐bromoesters, zinc dust and iodine in dioxane and/or tetrahydrofuran under irradiation by high intensity ultrasound (HIU) provide β‐hydroxy lariat ether esters in 79‐91% yields. HIU‐promoted Reformatsky reactions offer several advantages over customary thermal reaction conditions.
Synthesis and coordination properties of highly preorganised polyamine macrocycles
Authors: Bazzicalupi Carla , Bencini Andrea , Bianchi Antonio , Giorgi Claudia , Paoletti Piero , Valtancoli Barbara , Fusi Vieri , Garcia‐Españta Enrique , Llinares Josè M.
Published: March 2009

Synthesis and characterisation of the new macrocyclic ligands L1‐L4 are reported. The ligands present one or two pentaamine moieties, each containing two piperazine rings, linked by benzene or anthracene spacers. Interaction of L1 with H+, Cu(II), Zn(II), Hg(II), and Pd(II) and of L3 with H+, and Cu(II) has been studied by potentiometric titrations in 0.15 mol dm−3 NaCl aqueous solution at 298.1 ±0.1 K. The thermodynamic data suggest that in the metal complexes only three nitrogen donor atoms bind each metal ion. As a consequence of the low coordination number, these complexes are promising receptors for different molecules.
Synthesis of 2‐silaoxane via 1,3‐ photocycloaddition
Authors: Bahu Suhail , Fleming Steven A. , Nilsson Brad , Turner Tim
Published: March 2009

Irradiation of an aryl group with a silyl tethered alkene yields a tetracyclic 2‐silaoxane with high regiose‐lectivity. The multicyclic structure has been further modified to give an unstable tricyclic diol. Photocycloaddition between cyclopentene and phenylcyclopropane gave a single major cycloadduct without cyclopropyl ring opening, indicating that the putative radical intermediate involved in cycloaddition apparently has a very short lifetime if it exists at all.
Synthesis, alkali metal picrate extraction, and alkali metal cation binding selectivities of some new cage‐annulated polyoxamacrocyclic crown ethers
Authors: Marchand Alan P. , Huang Zilin , Chen Zhibing , Hariprakasha H. K. , Namboothiri I. N. N. , Brodbelt Jennifer S. , Reyzer Michelle L.
Published: March 2009

Five new cage‐annulated crown ethers, i.e., 4a, 4b, 6b, 11a, and 11b, have been synthesized and their respective alkali metal picrate extraction profiles along with that of a previously synthesized host molecule, 6a, have been obtained. These results are compared with the corresponding results obtained for electrospray ionization mass spectrometric (ESI‐MS) measurements of relative binding selectivities displayed by the same hosts toward a series of alkali metal chlorides. Among the crown‐5 hosts studied, 6a displays enhanced avidity toward complexation with K+ picrate in liquid‐liquid extraction experiments. Among the three crown‐6 hosts, 4b proved to be the best alkali metal picrate extractant and displayed significant levels of avidity toward complexation with the larger alkali metal cations (i.e., K+, Rb+, and Cs+). The trends in the picrate extraction and the ESI‐MS results obtained herein show several notable similarities and some differences. The similarities generally stem from size‐selective binding properties that are intrinsic to the different cavity sizes of the cage‐annulated macrocycles, whereas the differences reflect the important influence of solvation effects on the binding properties of the macrocycles.
New diazadi(and tri)thia‐21‐crown‐7 ethers containing 8‐hydroxyquinoline side arms
Authors: Song Hua‐Can , Chen Yi‐Wen , Song Ji‐Guo , Savage Paul B. , Xue Guo‐Ping , Chiara Joseph A. , Izatt Reed M. , Bradshaw Jerald S. , Krakowiak Krzysztof E.
Published: March 2009

A series of macrocyclic diazadi(and tri)thiacrown ethers containing two 5‐substituent‐8‐hydroxyquinoline side arms have been synthesized from the corresponding macrocyclic diazadi(and tri)thiacrown ethers. The crown ethers were obtained by reduction of the proper macrocyclic di(and tri)thiadiamides by borane‐tetrahydrofuran or by sodium borohydride‐boron trifluoride ethyl etherate‐tetrahydrofuran. The yields for the reduction of diamides by sodium borohydride‐boron trifluoride ethyl etherate‐tetrahydrofuran were higher than those by borane‐tetrahydrofuran. The following four methods were used to prepare macrocycles bearing two 8‐hydroxyquinoline side arms: (1) Mannich reaction with 8‐hydroxyquinoline; (2) Reductive animation with 8‐hydroxyquinoline‐2‐carboxaldehyde using sodium triacetoxyborohydride as the reducing agent; (3) Cyclization of N,N'‐bis(8‐hydroxyquinolin‐2‐ylmethyl)‐1,2‐bis(2‐aminoethoxy)ethane (38) with bis(α‐chloroamide) 5; and (4) A step‐by‐step process wherein macrocyclic trithiadiamide 11 was reduced by lithium aluminum hydride‐tetrahydrofuran to the cyclic monoamide 36, which smoothly reacted with 5‐chloro‐8‐hydroxyquinoline to produce monosubstituted‐macrocyclic monoamide 39.
Novel calix[4]cryptands: “Mappemonde II” and “Mill II”
Authors: Pulpoka Buncha , Kim Jong Sueng , Yang Seung Hwan , Vicens Jacques
Published: March 2009

Two novel calix[4]cryptands were synthesized from 1,3‐alternate calix[4]bis‐azacrown. “Mappemonde II” consists of one 1,3‐calix[4]bis‐azacrown wrapped by a benzo‐crown ether loop. “Mill II” is composed of two 1,3‐calix[4]bis‐azacrowns linked by two benzo‐crown ether strands.
A density functional theoretical study of the influence of cavities and water molecules on tautomerism: The case of pyridones and 1,2,4‐triazoles linked to crown ethers and esters
Authors: Alkorta Ibon , Elguero José
Published: March 2009

The tautomerism of pyridones and 1,2,4‐triazoles related to two crown ethers and two crown esters derived from these heterocycles was studied theoretically. For the four macrocycles, Bradshaw identified a single tautomer by X‐ray crystallography. To rationalize these findings, a series of calculations from simple models to crown derivatives have been carried out. The most interesting case concerns the observation, for the first time, of a 4H‐1,2,4‐triazole tautomer. To explain this result it was necessary to calculate the whole crown ester plus a caged water molecule was necessary.
The effect of twin‐tailed sidearms on sodium cation transport in synthetic hydraphile cation channels
Authors: Shabany Hossein , Pajewski Robert , Abel Ernesto , Mukhopadhyay Anindita , Gokel George W.
Published: March 2009

The preparation of novel tris(macrocycle)s that transport Na+ through phospholipid bilayers is reported. All of the reported structures have the following structural elements: sidechain‐macrocycle‐spacer‐macro‐cycle‐spacer‐macrocycle‐sidechain. The overall extension of the channel system is defined by the lengths of the spacer chains. The flexible sidearms are thought to be aligned with the lipid axis and opposite to the spacer chains. To the extent the spacer chains contribute to organization of the structure and isolation of the cation‐containing pore from the surrounding lipid chains, more hydrophobic chains are expected to enhance cation transport. A comparison of C12H25(CH2)12(CH2)12 C12H25, 1, with (C12H25)2N(CH2)2(CH2)12(CH2)12(CH2)2N(C12H25)2, 11, shows that the Na+ transport is, indeed, enhanced.
Crown ether strategy toward chemical activation of biological protein functions
Authors: Tsukube Hiroshi , Yamada Takashi , Shinoda Satoshi
Published: March 2009

The chemical activation of biological proteins is outlined, in which small molecules are used to alter the chemical and physical properties of biological proteins through direct or indirect interactions. Crown ethers have the potential to modulate the protein functions by supramolecular complexations, because they bind alkylammonium and other ionic residues of the proteins as well as ionic components in their systems. Two interesting examples are described in which crown ether derivatives improved the protein functions: (1) enhancement of reactivity and enantioselectivity in lipase‐catalyzed asymmetric reactions; and (2) generation of catalytic activity in the oxidation with cytochrome c. This chemical activation based on crown ether chemistry can be viewed as a complementary method to biological mutation in modifying the biological protein functions.
Synthesis of 7‐acetyloxy‐3,7‐dimethy1‐7,8‐dihydro‐6H‐isochromene‐6,8‐dione and its analogues
Authors: Suzuki Tsuneo , Tanemura Kiyoshi , Okada Chizuko , Arai The Late Kenichi , Awaji Akira , Shimizu Takahachi , Horaguchi Takaaki
Published: March 2009

7‐Alkanoyloxy‐3,7‐dimefhyl‐7,8‐dihydro‐6H‐isochromene‐6,8‐diones 12‐15 were synthesized in 69‐16% yields from the reaction of 2,4‐dihydroxy‐3‐methyl‐6‐(2‐oxopropyl)benzaldehyde 11 with p‐toluenesulfonic acid in various carboxylic acids such as acetic acid, propionic acid, butyric acid and heptanoic acid followed by oxidation with lead tetraacetate. On the other hand, (±)‐daldinin A 5 (oleate) was not obtained using oleic acid as a medium. In the cases of heptanoic acid and oleic acid, esters 16 and 17 were produced in 23 and 9% yields, respectively. 6,8‐Dihydroxy‐3,7‐dimethyl‐2‐benzopyrylium p‐toluenesulfonate 31 is considered as the intermediate for the production of 12‐15. Overall yields of isochromenes 12‐15 were 26‐6% starting from 2‐methylresorcinol for seven steps.
Dioxa‐[40]decaphyrin(1.0.1.0.0.1.0.1.0.0): An analogue of turcasarin with a “figure‐eight” structure
Authors: Sessler Jonathan L. , Seidel Daniel , Gebauer Andreas , Lynch Vincent , Abboud Khalil A.
Published: March 2009

The synthesis and characterization of two different furan containing analogues of turcasarin, namely 46,51 ‐dioxa‐2,11,15,20,24,33,37,42‐octapropyl‐turcasarin (7a) and 46,51 ‐dioxa‐2,11,24,33‐tetrapropyl‐15,20,37,42‐tetraethyl‐16,19,38,41‐tetramethyl‐turcasarin (7b) are described. While 7a was found to exhibit a “figure eight” structure in solution and in the solid state, 7b is believed to adopt a different, more symmetric conformation is solution.
New isomeric 2‐ortho‐(meta‐ and para‐) chloro‐(bromo and nitro‐)benzylthio‐6‐aminouracils
Authors: Wyrzykiewicz Elżbieta , Szponar Anna
Published: March 2009

Ten new ortho, meta and para substituted derivatives of 2‐benzylthio‐6‐aminouracils have been prepared. Electron Impact (EI) induced mass spectral fragmentation of these compounds was investigated. Fragmentation pathways are proposed on the basis of accurate mass and metastable transition measurements. The correlation between the intensities of the M+‐ and the selected fragment ions of these compounds is discussed. The data obtained create the basis for dinstinguishing isomers. The 1H and 13C NMR spectra of these compounds were assigned unambiguously using a combination of heteronuclear (HETCOR) spectra the chemical shifts. The data derived from these spectra can be used to differentiate the isomers.
Synthesis of 1,3,4‐oxa(or thia)diazaheterocycles starting from 2‐(pyrrol‐1'‐y1)phthalimide
Authors: Guesdon Anita , Fogain‐Ninkam Alain , Decroix Bernard , Netchitaïlo Pierre
Published: March 2009

1‐(1,3‐Dioxo‐1,3‐dihydro‐2H‐isoindol‐2‐yl)‐1H‐pyrrol‐2 carbaldehyde 4 was synthesized by Vilsmeier‐Haack reaction from 2‐(pyrrol‐1‐yl) phthalimide. Reduction of 4 by sodium borohydride, or action of Grignard reagents on 4 led to the corresponding alcohols 5 which were cyclized to pyrroloxadiazino isoin‐doles 1 by heating in the presence of silica gel. Transformation of the hydroxylactam 6 with acetic acid derivatives led to the esters 7 which gave, after saponification, pyrroloxa(or thia)diazepinoisoindolones 2 by intramolecular cyclization.
Synthesis of pyrimidinones by action of benzamidine on a benzocycloheptenic β‐keto ester
Authors: Muller Nadine , Granet Robert , Lepage Lucette , Krausz Pierre , Laval Jean‐Paul
Published: March 2009

The synthesis of a polycyclic heterocyclic ring system compound, ethyl 7‐hydroxy‐4‐oxo‐2‐phenyl‐4,5‐dihydro‐3H‐benzo[6,7]cyclohepta[1,2‐d]pyrimidine‐6‐carboxylate was carried out by condensation of benzamidine on diethyl 5,9‐dihydroxy‐7H‐benzo[a]cycloheptene‐6,8‐dicarboxylate, after opening and then closure of the seven membered ring.
Benzopyrans. Part 42. Reactions of 4‐Oxo‐4H‐1‐benzopyran‐3‐carbaldehyde with some active methylene compounds in the presence of ammonia
Authors: Ghosh Chandra Kanta , Ray Anirban , Patra Amarendra
Published: March 2009

The title aldehyde 1 in the presence of ammonia gives the pyridine derivatives 9‐11 respectively with acetylacetone, diethyl malonate and ethyl cyanoacetate, and ethyl (or methyl)‐l‐benzopyrano[4,3‐b]pyri‐dine‐3‐carboxylate 22 (or 23) with ethyl (or methyl) acetoacetate. Acetylacetone pretreated with ammonia condenses with 1 giving the fused pyridine 24. Ammonia converts the ester 6 to the pyridine 13 or 14. Chromic acid oxidation of 22 and 23 affords the coumarinopyridines 25 and 26, respectively.
A facile one step synthesis of 1,6 ‐dihydro‐7H‐pyrazolo[4,3‐d]‐pyrimidin‐7‐ones
Authors: Reddy Nalla Ram , Reddy Ghanta Mahesh , Reddy Battu Saida , Reddy Padi Pratap
Published: March 2009

A general synthetic approach to pyrazolo[4,3‐d]pyrimidines is reported. Aldehydes, arylideneanilines, carboxylic acids and orthoesters are used as one‐carbon units for bridging the two amino functions of 4‐amino‐1‐alkyl‐3‐propylpyrazole‐5‐carboxamides.
Synthesis of oxazolo[3,2‐b]hetero[1,2,4]thiadiazine S,S‐dioxides
Authors: Vega Salvador , Arranz María Esther , Arán Vicente J.
Published: March 2009

Six bromomethyl derivatives of the new 2,3‐dihydrooxazolo[3,2‐b]thieno[3,4‐e][1,2,4]thiadiazine 5,5‐dioxides, 2,3‐dihydrooxazolo[3,2‐b]thieno[2,3‐e][1,2,4]thiadiazine 5,5‐dioxides and 6,7‐dihydrooxazolo‐[3,2‐b]pyrazolo[4,3‐e][1,2,4]thiadiazine 9,9‐dioxides heterocyclic ring systems were synthesized. These compounds are good intermediates for the preparation and development of promising antiviral and psy‐chotropic drugs. The structures of the products are supported by different nmr spectroscopic methods and mass spectrometry.
Synthesis and antimicrobial activity of 3‐(N‐arylamino)‐2‐phenyl‐naphtho[1,3‐d]‐1,2‐oxaphosphole 2‐oxides
Authors: Haranath P. , Anasuyamma U. , Raju C. Naga , Reddy C. Devendranath , Reddy C. Suresh
Published: March 2009

The efficient preparation of cis‐3‐(N‐arylamino)‐2‐phenylnaphtho[1,3‐d]‐1,2‐oxaphosphole 2‐oxides 4 and 5 is described by a three‐component reaction involving phenyldichlorophosphine (2) 1‐hydroxy‐2‐naph‐thaldehyde/1‐hydroxy‐2‐acetonaphthone (1) and different substituted amines (3) in anhydrous benzene. The stereo structure, of the products (4 and 5), as well as the reaction mechanism of the cyclization is discussed. The title compounds (4 and 5) were fully characterized by NMR and mass spectral data. Their anti microbial activity was evaluated
Synthesis and thermolysis of the 2,3‐dihydro‐1H‐pyrole‐2,3‐diones, pseudopericyclic reactions of formyl(N‐phenylimidoyl)ketene: Experimental data and PM3 calculations
Authors: Saripinar Emin , Karataş Süleyman
Published: March 2009

The reactions of the 2,3‐dihydro‐1H‐furan‐2,3‐dione 1 with Schiff bases 2a‐f at 60–70°C furnish the corresponding 2,3‐dihydro‐1H‐pyrole‐2,3‐diones 3a‐f. The heating of 3a‐d afforded the corresponding 4‐methoxybenzoyl(N‐arylimidoyl)k:etenes 4a‐d as intermediates which undergo a very facile cyclization to quinoline‐4‐ones 5a‐d. According to our PM3 calculations, fragmentation of 4‐formyl‐2,3‐dihydro‐1H‐pyrole‐2,3‐dione and 1,4‐cyclization of formyl(N‐phenylimidoyl)k:etene IN1 to azetin‐2‐one IN2 and oxe‐tone IN3 are pseudopericyclic reactions with two orbital connections, proceed via planar transition structures. Due to to the possibility of syn and anti conformations of the imine phenyl, there are eight E/Z‐iso‐mers of IN1. In addition, we have also calculated reaction mechanism of formation of quinoline‐4‐ones by the PM3 method.
Gem‐disubstituted 4‐oxocyclohexanes: Source for spiro heterocycles
Authors: Padmavathi Venkatapuram , Basha Shaik Mahaboob , Subbaiah Dandu Rangayapalle Chinna Venkata , Reddy Tippireddy Venkata Ramana , Padmaja Adivireddy
Published: March 2009

Novel spiro heterocycles, substituted spiro‐pyrimidine, pyrazole and isoxazole compounds are prepared by the cyclocondensation of 4‐oxocyclohexane gem‐dicarboxylates and cyano esters with nucleophiles.
Synthesis of macrocycles incorporating azo‐bis(azofurazan) framework
Authors: Sheremetev A. B. , Ivanova E. A. , Dmitriev D. E. , Kulagina V. O. , Averkiev Boris B. , Antipin Mikhail Yu.
Published: March 2009

A series of macrocycles containing four furazan rings bonded by three azo bonds 2, 5 and 7 have been synthesized from the common precursor, 3‐amino‐3′‐nitro(azofurazan) 3. The macrocycles closure is a result of NN bond formation at oxidative cyclization of corresponding bis(3‐aminofurazan‐4‐yl) precursors. X‐Ray crystal structures of macrocycles 2, 2•AcOH, 11 and 13 are reported.
Aromatization and ring cyclization: A better understanding on the ring cyclization mechanism of 3‐amino‐6‐hydrazino‐1,2,4‐triazin‐5(2H)‐one reacted with acetic acid in N,N‐dimethylformamide
Authors: Hwang Long‐Chih , Wu Rang‐Rong , Tu Chun‐Hsien
Published: March 2009

In this paper we report that the title compound (3) reacts with excess N,N‐dimethylformamide (DMF) containing two equivalents of acetic acid to afford 6‐amino‐1,2,4‐triazolo[3,4‐f][1,2,4]triazin‐8(7H)‐one (1). When 3‐amino‐2‐benzyl‐6‐hydrazino‐1,2,4‐triazin‐5(2H)‐one (6), the N‐2 benzylated derivative of 3, is treated under the same conditions, ring cyclization does not occur; instead, 3‐amino‐2‐benzyl‐6‐(2‐formyl‐hydrazino)‐1,2,4‐triazin‐5(2H)‐one (7) is formed. Single‐crystal X‐ray analysis of a 3‐ethyl derivative of compound 1 reveals the predominant tautomeric structure to be the 7H‐tautomer (7H‐1). From these results, we propose a reasonable cyclization mechanism that incorporates two important points: (1) the tautomerism of the N‐2 hydrogen with the C‐5 oxo group aromatizes the 1,2,4‐triazine ring, and (2) the DMF is proto‐nated by acetic acid on the nitrogen atom, then deamination occurs where DMF is attacked by the 6‐hydrazino group of 3 or 6.
Synthesis of novel 4‐pyrazolyl‐2‐oxo‐1,2,3,4‐tetrahydropyrimidines promoted by phosphotungstic acid
Authors: Sivaprasad Ganesabaskaran , Peramal Paramasivan T.
Published: March 2009

Phosphotungstic acid, a keggin's type heteropoly acid catatalysed Biginelli reaction was carried out using pyrazole aldehyde, ethyl acetoacetate and urea to synthesis novel 4‐pyrazolyl ‐2‐oxo‐1,2,3,4‐tetrahydropy‐ rimidines.
A study of substituent effect on 1H and 13C NMR spectra of mono, di and poly substituted carbazoles
Authors: Bonesi Sergio M. , Ponce Maria A. , Erra‐Balsells Rosa
Published: March 2009

1H and 13C NMR spectra of several substituted carbazoles (Series 1, 2, 3, 4 and 5) were measured. Substituent chemical shifts (SCS's) and Lynch correlations of 1H and 13C nuclei were calculated and the substituent effect on the NMR phenomena was determined. Atomic charge densities for carbazoles of Series 1, 2, 3, 4 and 5 were calculated by using the semi empirical PM3 method. These values also show a linear correlation with the 13C chemical shifts.
A new method for the generation of α‐nitrosoolefins from ketooximes and its application to the synthesis of 5,6‐dihydro‐4H‐1,2‐oxazine derivatives
Authors: Gaonkar S. L. , Rai K. M. Lokanatha
Published: March 2009

Reaction of ketooximes containing α‐methylene group with chloramine‐T followed by treatment with tri‐ethylamine leads to the formation of α‐nitrosoolefins via α‐nitrosochloride, which can react in situ intermol‐ecularly with olefinic compounds to produce 5,6‐dihydro‐4H‐1,2‐oxazine derivatives in good yield.
Synthesis and prediction of bioactivity of new nitroimidazole derivatives
Authors: Kowalski Piotr , Nowak Krystyna , Szpakiewicz Barbara
Published: March 2009

Syntheses of 1‐propyl derivatives of 2‐methyl‐5‐nitroimidazole (11‐17), containing various azanaphtha‐lene systems attached at 3‐position of the propyl group have been described. Due to structural similarity of the derivatives 11‐17 with metronidazole, an antibacterial and antiprotozoal drug, pharmacological properties of the target compounds were predicted using the PASS program. Polar surface area (PSA) parameter was also applied for estimation of the physical properties of 11‐17 as drug‐like candidates.
A convenient, rapid, and highly selective method for synthesis of new pyrazolo[1,5‐a]pyrimidines via the reaction of enaminones and 5‐amino‐1H‐pyrazoles under microwave irradiation
Authors: Ming Li , Shuwen Wang , Lirong Wen , Huazheng Yang , Xiuli Zhang
Published: March 2009

Twelve new 7‐aryl‐3‐cyanopyrazolo[1,5‐a]pyrimidines (3a‐f) and ethyl 7‐arylpyrazolo[1,5‐a]pyrimidine‐3‐carboxylates (3g‐l) have been conveniently synthesized by the reaction of enaminones with 5‐amino‐1H‐pyrazoles in good yields under microwave irradiation. With one substituded enaminone, only one regioiso‐mer was obtained. The structures of new compounds were fully confirmed by elemental analysis, ir, 1H nmr and X‐ray diffraction (XRD) analysis. A plausible reaction mechanism for the synthesis of title compounds is presented. The antifungal activities of some compounds are also reported.
Studies with quinolines: New synthetic routes to 4H,5H,6H,9H‐benzo[ij]pyrano[2,3‐b]quinolizine‐8‐one, 4H‐pyrano[2,3‐b]pyridine, 2H‐pyran‐2‐one and pyranopyridoquinoline derivatives
Authors: El‐Taweel Fathy Mohamad Abdel Aziz
Published: March 2009

Several new benzo[ij]pyrano[2,3‐b]quinolizine‐8‐ones 5 and 4H‐pyrano[2,3‐b]pyridine 8 derivatives were synthesized from 4‐hydroxyquinolines 1. Reacting 3‐acetyl‐4‐hydroxy‐1‐phenyl‐1H‐quinoline‐2‐one with dimethylformamide dimethylacetal afforded 3‐(3‐Dimethylarnino‐acryloyl)‐4‐hydroxy‐1‐phenyl‐1H‐quinolin‐2‐one 9. This reacted with hippuric acid and diethyl 3‐oxoglutarate to give 2H‐pyran‐2‐one 13 and pyranopyridoquinoline 17 respectively.
Synthesis and 1H NMR structural analysis of 11‐aryl/heteroarylnaphtha[2,1‐b]furans: X‐ray crystal structure of 11‐(4′‐pyridyl)naphtho[2,1 ‐b]furan
Authors: Mashraqui Sabir H , Patil Mamta B , Sangvikar Yogesh , Ashraf Mohamed , Mistry Hitesh D , Dâub Elise Trân Huu , Meetsma Auke
Published: March 2009

Synthesis of biaryl type systems, 11‐aryl/heteroarylnaphtho[2,1‐b]furans 8‐11 has been described with a view to studying the conformational orientation of C‐11 aryl/heteroaryl groups. Synthesis of 8‐11 was accomplished by a two‐step sequence involving O‐alkylation of 2‐naphthol with appropriate halo‐ketones 2‐4, followed by cyclization of the resulting naphthoxy‐ketones 5‐7 with methanesulphonic acid. The structures of 8‐11 are based on detailed 2D NMR spectral analysis. The H8 in these compounds is not subject to significant anisotropic upfield shielding effects. The slightly upfield chemical shift of H8 in molecules 9‐11, relative to 8 has been correlated with the electron density at C17 and C8 positions. While molecular modeling indicated dihedral angle (φ) between the C11 aryl/heteroaryl groups and the naphthofuran plane to be in the range of 70–60° in 8‐10, a single X‐ray crystal structural analysis of 11‐(4′‐pyridyl)naphtho[2,1‐b]furan 10 indicated (φ) of 64.36°. In view of significant deviations from the orthogonal oreintation, the absence of any significant anisotropic shielding in 8‐11 is not entirely unexpected.
Synthesis of hantzsch 1,4‐dihydropyridines under solvent‐free condition using zn[(L)proline]2 as lewis acid catalyst
Authors: Sivamurugan V. , Kumar R. Suresh , Palanichamy M. , Murugesan V.
Published: March 2009

The present short communication describes a Lewis acid (Zn[(L)proline]2) catalysed one pot synthesis of Hantzsch 1,4‐dihydropyridine (DHP) derivatives under solvent‐free condition by conventional heating and microwave irradiation. The Lewis acid catalyst Zn[(L)proline]2 used in this reaction afford moderate to good yield. The catalyst is reusable upto five cycles without appreciable loss of its catalytic activity.
Synthesis and antiviral evaluation of some carbonucleoside analogues
Authors: Alho Miriam A. Martins , Errea Maria I. , Sguerra Vanesa L. , D'Accorso Norma B. , Talarico Laura B. , García Cybele C. , Damonte Elsa B.
Published: March 2009

1,2‐O‐Isopropylidene‐α‐L‐threofuranosyl heterocyclic derivatives were synthesized from 1,2‐O‐iso‐propylidene‐α‐D‐xilopentadialdo‐1,4‐furanose and tested for antiviral activity against herpes simplex virus type 1, dengue virus type 2 and Junin virus. For comparative propose, the antiviral activity of some of their pyranosyl analogues were also tested. The furanosyl derivatives showed to be moderate inhibitors of Junin virus and, in general, proved to be more effective than the pyranosyl analogues.
Rapid synthesis of 2,5‐disubtituted 1,3,4‐thiadiazoles under microwave irradiation
Authors: Lebrini Mounim , Bentiss Fouad , Lagrenée Michel
Published: March 2009

The one pot, three‐components condensation of aromatic aldehydes, hydrazine and sulfur in ethanol under microwave irradiation provided symmetrically 3,5‐disubstituted 1,3,4‐thiadiazoles in high yields and good purity. This reaction must be conducted under pressure of hydrogen sulfide produced in‐situ. The structure of the compounds was confirmed by 1H, 13C NMR, MS and elemental analysis.
Heterocyclic synthesis: A convenient route to some 2‐mercepto 1,3,4‐oxadiazole and green chemistry microwave‐induced one‐pot synthesis of 2‐aryl 1,3,4‐oxadiazole in quinazolone and their antibacterial and antifungal activity
Authors: Desai A. R. , Desai K. R.
Published: March 2009

Several 6‐substituted‐3‐[(5‐mercepto‐1,3,4‐oxadiazol‐2‐yl)methyl]‐2‐substituted quinazolin‐4(3H)‐one or 6‐substituted‐3‐[4‐(5‐mercepto‐1,3,4‐oxadiazol‐2‐yl)phenyl]‐2‐substituedquinazolin‐4(3H)‐one 2(a‐l) and 6‐substituted‐3‐[(5‐phenyl‐1,3,4‐oxadiazol‐2‐yl)methyl]‐2‐substitutedquinazolin‐4(3H)‐one or 6‐substi‐tuted‐3‐[4‐(5‐phenyl‐1,3,4‐oxadiazol‐2‐yl) phenyl]‐2‐substitutedquinazolin‐4(3H)‐one 3(a‐l) were synthesized using conventional and microwave techniques respectively and were screened for antibacterial and antifungal activity.
Copper dipyridine dichloride as a mild and efficient catalyst for a one pot condensation bigenelli reaction
Authors: Kumar V. Naveen , Someshwar P. , Reddy P. Narsimha , Reddy Y. Thirupathi , Rajitha B.
Published: March 2009

The condensation reaction of aldehydes, β‐ketoesters and urea/thiourea in presence of a catalytic amount of CuPy2Cl2 complex proceeded under very mild reaction conditions in high yield (80‐90%).
Synthesis of 1,2,4‐triazolo[1,5‐d]‐1,2,4‐triazine‐5‐thiones
Authors: Heravi Majid M. , Montazeri Naser , Rahimizadeh Mohammad , Bakavoli Mehdi , Ghassemzadeh Mitra
Published: March 2009

In an attempt to discover bicyclic compounds containing the 1,2,4‐triazine moiety, 1,2,4‐triazolo[1,5‐d]‐1,2,4‐triazine‐5‐thiones from one pot reaction of arylnitriles with 4‐amino‐1,2,4‐triazine‐3‐thione‐5‐one in the presence of potassium tert‐butoxide were synthesized.
Synthesis of some new substituted ethanone hydrazones containing 1H‐1,2,4‐triazole and thiazole
Authors: Liu Fang‐Ming , Sun Ya‐Dong , Xie Zheng‐Feng
Published: March 2009

Three new thiosemicarbazones have been synthesized by condensation reaction of 2‐bromo‐1‐arylethanones with thiosemicarbazide, which reacted with various 2‐bromo‐1‐arylethanones in ethanol under refluxing to give a series of substituted ethanone hydrazone derivatives. Their structures were confirmed by elemental analysis, IR, 1H NMR, and MS spectra.
Synthesis and intramolecular cyclization of 2‐methylsulfany‐4‐oxo‐3(4H)‐quinazolinyl)acetohydrazide
Authors: Burbuliene Milda M. , Bobrovas Olegas , Vainilavicius Povilas
Published: March 2009

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Treatment of ambident sodium salt of 2‐methylsulfanyl‐4(3H)‐quinazolinone with methyl bromoacetate resulted in N(3)‐alkyl ester formation. Reaction of the resulted ester with hydrazine hydrate gave 2‐methylsulfanyl‐4‐oxo‐3(4H)‐quinazolinyl)acetohydrazide, which underwent intramolecular cyclization under heating in dimethylformamide to give 1‐aminoimidazo[2,1‐b]quinazoline‐2,5(1H,3H)‐dione. The latter took place in acylation reaction and in condensation with aromatic aldehydes.
Preparation of 6‐azaoxindole (6‐azaindol‐2(3H)‐one) and substituted derivatives
Authors: Andreassen Einar J. , Bakke Jan M.
Published: March 2009

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A general synthesis of 6‐azaoxindoles, substituted in the 3‐ and 5‐position, has been developed starting from 4‐methoxycarbomethyl‐3‐nitropyridine, via hydrogenation of the nitro group and cyclisation of the resulting 3‐amino‐4‐methoxycarbomethyl‐pyridine.
Regioselective synthesis of novel spiroheterocyclic framework via the 1,3‐dipolar cycloaddition
Authors: Hu Xiaofen , Feng Yaqing , Qiao Kangjian , Zhou Weiyi
Published: March 2009

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A series of novel dispiro[oxindole‐fused pyrimidine]pyrrolidine ring systems 4a‐f were synthesized by the regioselective 1,3‐dipolar cycloaddition reaction of the 2‐arylmethylene‐7‐benzyl‐9‐(benzylidene)tetrahydropyrido[4,3‐d]thiazolo[3,2‐a]pyrimidin‐3‐ones 1a‐f with azomethine ylides, generating by the decarboxylative route from isatin 2 and sarcosine 3, in moderate to good yields. The regiochemistry of designed dispiroheterocyclic compounds 4a‐f was established by single crystal X‐ray structure and spectroscopic techniques.
Synthesis of new double (spin and fluorescence) sensor reagents and labels
Authors: Bognár Balázs , Øz Erzsébet , Hideg Kálmán , Kálai Tamás
Published: March 2009

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New double (spin and fluorescence) sensors were synthesized from aminocoumarin, pyrene and 4‐nitrobenzofurazan dyes and from five‐ or six‐membered nitroxides or their diamagnetic derivatives with aromatic nucleophylic substitution, Suzuki cross‐coupling reaction and acylation reactions. The new compounds exhibit fluorescence emission between 382‐529 nm affording various utilization possibilities.
Synthesis of 2‐amino‐s‐triazino[1,2‐a]benzimidazoles as potential antifolates from 2‐guanidino‐ and 2‐guanidino‐5‐methylbenzimidazoles
Authors: Dolzhenko Anton V. , Chui Wai‐Keung
Published: March 2009

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The syntheses of 2‐amino‐s‐triazino[1,2‐a]benzimidazoles from 2‐guanidinobenzimidazoles were successfully carried out by a ring annelation reaction. The regiochemistry of the ring closure of 5‐methyl‐2‐guanidinobenzimidazole with diethyl azodicarboxylate, aldehydes, acetone, diethyl ethoxymethylenemalonate and orthoesters, leading to the formation of s‐triazine ring was studied. High regioselectivity was not observed in any of these reactions. However, the synthesis of s‐triazino[1,2‐a]benzimidazole system was found to be more regioselective than its 3,4‐dihydro analogue. NOESY experiment indicated that the compound, 2‐amino‐4,4‐dimethyl‐3,4‐dihydro‐s‐triazino[1,2‐a]benzimidazole existed predominantly as the 3,4‐dihydro tautomer in dimethyl sulfoxide. It was found to inhibit bovine dihydrofolate reductase with IC50 10.9 μM.
Synthesis of quinolin‐4‐yl substituted malonates, cyanoacetates, acetoacetates and related compounds
Authors: Stadlbauer Wolfgang , Täubl Anna E. , Dang Hoai V. , Reidlinger Claudia , Zangger Klaus
Published: March 2009

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4‐Chloro‐ or 4‐tosyloxyquinolines 1 and 10 react with CH‐acidic compounds such as malonates 2a,b, ethyl cyanoacetate (2c), malononitrile (2d), ethyl acetoacetate (2e), acetylacetone (2f) or dimedone (2g) under mild conditions and good yields to quinolin‐4‐yl substituted derivatives 3‐8 and 11. With 3‐phenylsulfonylquinolones 1i‐k a redox reaction to 2‐hydroxy‐2‐quinolin‐4‐yl‐malonates 9 was observed. Amination of 3‐nitroquinolinyl malonate 3f leads to malonester‐amides 13 and 14.
Racemic and diastereoselective synthesis of aryl and heteroaryl tetrahydroisoquinolines via the pictet‐spengler reaction
Authors: Aubry Sylvain , Pellet‐Rostaing Stéphane , Lemaire Marc , Faure René
Published: March 2009

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New tetrahydroisoquinolines were synthesized by the Pictet‐Spengler reaction. Influence of a wide range of aryl and heteroaryl aldehydes, was investigated in the cyclization step with 3,4‐dimethoxyphenylethylamine 1, L‐DOPA 2 and L‐3,4‐dimethoxyphenylalanine methyl ester 3. Compounds 2 and 3 served as probes to assess the efficiency of two Pictet‐Spengler reactions with respect to their diastereoselectivity, in order to obtain optically active diastereoisomers. Cis‐ and trans‐diastereoisomers were obtained in short reaction times with moderate to good isolated yields (20‐79%). Both nmr and X‐ray analyses confirmed the expected diastereoisomer configurations.
Synthesis and characterization of 4‐aryl‐5‐(1‐aryl‐2‐methyl‐2‐nitropropyl)‐1,2,3‐selenadiazoles
Authors: Saravanan Sivaperuman , Nithya Arumugam , Muthusubramanian Shanmugam
Published: March 2009

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The synthesis of a new set of selenadiazoles, 4‐aryl‐5‐(1‐aryl‐2‐methyl‐2‐nitropropyl)‐1,2,3‐selenadiazoles (4) derived from 2‐[4‐methyl‐4‐nitro‐1,3‐diarylpentylidene]‐1‐hydrazinecarboxamide (3) has been reported. THF has been found to be the solvent of choice for this reaction. Structural features of 3 and 4 have been analyzed by NMR and X‐ray techniques.
Syntheses of armed‐macrocycles by reductive amination using NaBH(OAc)3 under 1 MPa
Authors: Habata Yoichi , Osaka Futoshi , Yamada Sachiko
Published: March 2009

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Armed‐monoaza‐12‐crown‐4, monoaza‐15‐crown‐5, diaza‐12‐crown‐4, diaza‐18‐crown‐6 ethers, and 1,4,7,10‐tetraazacyclododecane having aromatic pendants were prepared by the reductive amination of the corresponding macrocycles with aromatic carboxyaldehydes in the presence of NaBH(OAc)3. Reductive amination under 1 MPa conditions provided significant shortening of the reaction time and yield enhancements.