bluuebunny/crossref_metadata_2025_split huggingface dataset:
The synthesis of heterocyclic analogs of bisantrene
Authors: Fields T. L. , Lin Yang‐i , Warren J. D. , Lang S. A. 
Published: April 2009

AbstractBisguanylhydrazones of anthracene‐9,10‐dicarboxaldehyde have demonstrated excellent antitumor activity. Heterocyclic analogs were synthesized in an effort to expand or modify the activity profile.
Novel diazinyl 3‐pyridyl ketones: Efficient synthesis and complete assignment of 1H and 13C NMR spectra
Authors: Heinisch Gottfried , Langer Thierry , Lukavsky Peter 
Published: April 2009

AbstractThe preparation of six diazinyl 3‐pyridyl ketones 3–8 is described. Detailed 1H and 13C nmr data of these novel building blocks are given.
Nitrogen bridgehead compounds. Part88. Synthesis of 3H, 7H‐[1,4]diazepino[3,4‐b]quinazoline‐3,7‐diones
Authors: Szabó Mónika , Kökösi József , Örfi László , Kovács Attila , Hermecz István 
Published: April 2009

Abstract3H,7H‐[1,4]Diazepino[3,4‐b]quinazolone‐3,7‐diones 9, 11 were synthesized starting from 2‐(1‐bromo‐ethyl)quinazolin‐4(3H)‐ones 3 and 17via2‐[1‐(4‐methoxyphenylamino)ethyl]quinazolin‐4(3H)‐ones 4 and 18. Cyclization of 3‐[2‐(1‐bromoethyl)‐4‐oxo‐3,4‐dihydroquinazolin‐3‐yl)propionic acid 14 by the action of triethylamine provided the first representative of the tricyclic 7H‐[1,4]oxazepino[3,4‐b]quinazoline‐3,7‐dione system, compound 15. The new tricyclic derivatives 9, 11 and 15 are characterized by uv, ir and1H nmr spectroscopy.
Synthesis of regioisomeric 6,9‐(chlorofluoro)‐substituted benzo[g]quinoline‐5,10‐diones, benzo[g] isoquinoline‐5,10‐diones and 6‐chloro‐9‐fluorobenzo[g]quinoxaline‐5,10‐dione
Authors: Krapcho A. Paul , Gallagher Cynthia E. , Hammach Abdelhakim , Ellis Michael , Menta Ernesto , Oliva Ambrogio 
Published: April 2009

AbstractTreatment of difluoro or chloro fluoro‐substituted benzyl bromides 5a‐c with zinc dust in tetrahydro‐furan leads to the corresponding benzylic zinc bromides 6a‐c. These organometallics on treatment with chlorosubstituted heterocyclic esters 4A and 4B mediated by nickel catalysis undergo couplings to yield dihalobenzyl substituted heterocyclic esters 7Aa‐c and 7Ba‐c. Treatment of 4c with 6c under Pd catalysis leads to 7Cc. The acids 8, prepared by hydrolysis of these esters, with treatment of fuming sulfuric acid undergo cyclizations and oxidations to yield the desired regioisomeric dihalo‐substituted heterocyclic quinones 2.
Synthesis of optically active 1,2,3‐substituted‐1,4,5,6‐tetrahydro‐7H‐indolones
Authors: Nitti P. , Pitacco G. , Pizzioli A. , Valentin E. 
Published: April 2009

AbstractTrisubstituted 1,4,5,6,‐tetrahydro‐7H‐indolones are obtained in a one‐pot synthesis from conjugated nitroolefins and α‐ketoenamines derived from α‐amino esters and cyclohexane‐1,2‐dione. In some cases bicyclo[3.2.1]octan‐8‐one and 1,2‐oxazine N‐oxide derivatives are isolated.
Synthesis of novel pyridazino[3,4‐b]quinoxalines
Authors: Kim Ho Sik , Kim Eun Kyoung , Kim Sung Sik , Park Yong Tae , Hong Young Seuk , Kurasawa Yoshihisa 
Published: April 2009

AbstractThe pyridazino[3,4‐b]quinoxaline 12 was synthesized by the cyclization of the α‐arylhydrazonoacyl‐hydrazide 11. The reaction of compound 12 with phosphoryl chloride gave pyridazino[3,4‐b]quinoxaline 13, whose reactions with sodium azide or cyclic secondary amines provided pyridazino[3,4‐b]quinoxalines 14,17 and 18, respectively. The acylhydrazide 15 was also cyclized to pyridazino[3,4‐b]quinoxaline 16.
Basicities of thiazole heterocyclic compounds and the reaction of 3‐methyl‐2‐methylimino‐Δ4‐thiazolines with ethyl bromoacetate and 2‐bromoacetophenone
Authors: Kim Dong Chan , Yoo Kyung Ho , Shin Kye Jung , Park Sang Woo , Kim Dong Jin 
Published: April 2009

AbstractThe pKa′s of several thiazole heterocyclic compounds have been determined and represent products with significantly high values. Because of their high basicities, sometimes these compounds were able to act as not only nucleophiles but also strong organic bases. 4‐Substituted‐3‐methyl‐2‐methylimino‐Δ4‐thiazolines 5a‐d reacted with ethyl bromoacetate in refluxing benzene, giving the corresponding N‐alkylated salts 8a‐d, while the products obtained from the reaction with 2‐bromoacetophenone in the presence of base were pyrrolothiazines 10b‐d.
1,2,3‐Triazolo[4,5‐d]‐1,2,4‐triazolo[4,3‐b]pyridazines
Authors: Biagi Giuliana , Giorgi Irene , Livi Oreste , Manera Clementina , Scartoni Valerio 
Published: April 2009

AbstractSome new 1,2,3‐triazolo[4,5‐d]‐1,2,4‐triazolo[4,3‐b]pyridazines were prepared starting from the corresponding 1,2,3‐triazolo[4,5‐d]pyridazines via the formation of the 1,2,4‐triazole ring, by condensation of an appropriate monocarbon fragment with the 4‐hydrazino substituent and the nitrogen atom in the 5 position of the heterocycle. Condensation of 4‐phenylhydrazino substituted derivatives with formic acid gave zwitterionic compounds.
Synthesis of alkyl 2‐phenylnicotinates
Authors: Yamauchi M. , Shirota M. , Tsugane A. 
Published: April 2009

AbstractVarious alkyl 6‐ethoxy‐2‐phenyl‐5,6‐dihydro‐4H‐pyran‐3‐carboxylate 2A are easily converted to the corresponding nicotinates 3 by reaction with hydroxylamine hydrochloride in refluxing absolute ethanol.
Synthesis of imidazo[4,5‐b]pyridines from aminoimidazolecarbaldehydes
Authors: Perandones Francisco , Soto Jose L. 
Published: April 2009

Abstract4‐Amino‐1,2‐dimethylimidazole‐5‐carbaldehyde (1) and 5‐amino‐1‐methylimidazole‐4‐carbaldehydes 3 were prepared by reduction of the corresponding aminoimidazolecarbonitriles 2 and 4. Condensation of 1 and 3 with carbonitriles, ketones and polyfunctional carbonyl compounds bearing the‐CH2CO‐moiety afforded to the imidazo[4,5‐b]pyridine derivatives.
Gas phase thermolysis of pyrazolines. 5. Electronic structure and gas phase thermolysis of tetrazole derivatives studied by photoelectron spectroscopy
Authors: Awadallah Adel , Kowski Klaus , Rademacher Paul 
Published: April 2009

AbstractThe photoelectron spectra of substituted tetrazoles 1–3, 1,4‐dihydro‐5H‐tetrazol‐5‐ones 4–9, and 1,4‐dihydro‐5H‐tetrazole‐5‐thiones 10–15 have been recorded. Based on PM3 and some ab initio calculations, the ionization potentials have been assigned to molecular orbitals. Gas‐phase thermolyses of 1–15 have been studied by real‐time gas analysis controlled by photoelectron spectroscopy. Compounds 1 and 2 lose formaldehyde and thioformaldehyde, respectively, leaving unsubstituted tetrazole (16), which decomposes mainly through extrusion of a nitrogen molecule and formation of cyanamide. Thiirane is split off from 3, and the remaining molecule decomposes into smaller products. Compounds 4–9 are cleaved by [3+2] cycloreversion to isocyanates and azides. Some of the unsymmetrically substituted compounds exhibit a marked selectivity in this reaction. For thiones 10–15 [3+2] cycloreversion is the main way of decomposition affording isothiocyanates and azides. In addition, the sulfur atom can split off and dimerize or abstract hydrogen atoms to form hydrogen sulfide. Some products like thiirene, formaldehyde, thioformaldehyde and acetaldehyde are generated solely from substituents. Photoelectron spectroscopy proved to be an excellent method for such thermolysis studies.
Synthesis and DNA binding properties of bis‐9‐acridinyl derivatives containing mono‐, di‐and tetra‐viologen units as a connector of bis‐intercalators
Authors: Takenaka Shigeori , Sato Hirotaka , Ihara Toshihiro , Takagi Makoto 
Published: April 2009

AbstractBis‐9‐acridinyl derivatives 1–3 containing mono‐, di‐and tetra‐viologen units as a rigid connector were synthesized. The binding studies of these intercalators for natural and synthetic DNAs showed that these compounds act as bis‐intercalators where viologen moieties lie in the minor groove of the DNA duplex. The DNA binding affinity of the intercalators was enhanced with an increase in the number of the viologen unit.
Furopyridines. XX. Wittig‐horner reaction of a phosphonate of reissert analogues of furo[3,2‐c]‐, ‐[2,3‐c]‐ and ‐[3,2‐b]pyridines
Authors: Shiotani Shunsaku , Tsukamoto Youichi , Kitagawa Yasuyuki 
Published: April 2009

AbstractFuro[3,2‐c]‐(1a), ‐[2,3‐c]‐ (1b) and ‐[3,2‐b]pyridine (1c) were reacted with isopropyl chloroformate and trimethyl phosphite to give dimethyl 5‐isopropoxycarbonyl‐4,5‐dihydrofuro[3,2‐c]pyridine‐4‐phosphonate (2a), dimethyl 6‐isopropoxycarbonyl‐6,7‐dihydrofuro[2,3‐c]pyridine‐7‐phosphonate (2b) and dimethyl 4‐isopropoxycarbonyl‐4,7‐dihydrofuro[3,2‐b]pyridine‐7‐phosphonate (2c) as unstable syrups. Reaction of 2b and 2c with n‐butyllithium and then with benzaldehyde, p‐methoxybenzaldehyde, p‐cyanobenzalde‐hyde or propionaldehyde afforded the normal Wittig reaction products 5b‐H, 5b‐OMe, 5b‐CN, 5b‐Et, 5c‐H, 5c‐H, 5c‐OMe and 5c‐CN, except for 2b with propionaldehyde. While, the same reactions of compound 2a and the reaction of 2b with propionaldehyde afforded the unexpected products, 5‐isopropoxycar‐bonylfuro[3,2‐c]pyridinio‐4‐aryl‐(or ethyl)methoxides 3a‐H, 3a‐OMe, 3a‐CN and 3a‐Et, 4‐(1′‐aryl(or ethyl)‐1′‐hydroxymethyl)furo[3,2‐c]pyridines 4a‐H, 4a‐OMe, 4a‐CN and 4a‐Et accompanying formation of the normal products. Treatment of the normal Wittig reaction products with lithium diisopropylamide and then with acetone gave the derivatives alkylated at the 2‐or the benzylic positions.
Photochemical reactions of 1‐methyl‐4,6‐diaryl‐2(1H)‐pyrimidinones in the presence of thiols
Authors: Nishio Takehiko , Kato Michiyo 
Published: April 2009

AbstractPhotochemical reactions of 1‐methyl‐4,6‐diaryl‐2(1H)pyrimidinones 1a‐b in the presence of thiols 2 are described. Irradiation of 1‐methyl‐4,6‐diaryl‐2(1H)‐pyrimidinones 1a‐b in benzene in the presence of thiols 2 gave the unexpected 2:1‐adducts, 3‐methyl‐4,6‐diaryl‐5‐aralkylthio‐6‐(1′‐methyl‐4′,6′‐diaryldihydro‐pyrimidin‐2‐on)yl‐1,3‐diazabicyclo[2.2.0]hexan‐2‐ones 3‐6, of 1 and 2, whereas irradiation of 1a‐b alone in benzene resulted in recovery of the unchanged 1a‐b.
Study on the structures of 2‐substituted iminothiazolidine derivatives
Authors: Sakae Masatoshi , Katsurada Masanori , Watanabe Mayumi , Yoneda Fumio , Nishigaki Sadao , Ishida Toshimasa 
Published: April 2009

AbstractThe reaction of 2‐bromoethylamine 1 with methylisothiocyanate 2 under mild condition gave 2‐methyl‐amino‐2‐thiazoline 3 as the major product together with two kinds of byproducts, 3‐(N‐methylthiocar‐bamoyl)‐2‐methyliminothiazolidine 4 and N,N′‐dimethyl‐N‐(2‐thiazolin‐2‐yl)thiourea 5. Thermal isomer‐ization of 5 to 4 was observed. The structures of the byproducts were confirmed by X‐ray crystallography.
Synthesis of unsymmetrically substituted dodecakis(trifluoroethoxy)‐phthalocyaninato vanadyl complexes
Authors: Tian Minquan , Wada Tatsuo , Sasabe Hiroyuki 
Published: April 2009

AbstractThree novel unsymmetrical vanadyl dodecakis(2,2,2‐trifluoroethoxy)phthalocyaninates with nitro, amino or with no substitution were synthesized by a statistical condensation of 3,4,5,6‐tetrakis(2,2,2‐trifluoroethoxy)phthalonitrile with 4‐nitro, 4‐amino or 4‐unsubstituted phthalonitrile, and separated by common column chromatography. These highly soluble phthalocyanines were characterized by elemental analysis, ir and 1H‐nmr, uv‐visible and fast‐atom‐bombardment mass spectroscopy. Their uv‐visible absorption spectra in solution and in doped poly(methyl methacrylate) films showed that they were less aggregated unsymmetrical phthalocyanines.
1,3‐Dipolar cycloaddition reactions of cyclooctyne with pyridinium dicynomethylides
Authors: Matsumoto Kiyoshi , Ohta Ryuji , Uchida Takane , Nishioka Hiroyasu , Yoshida Maki , Kakehi Akikazu 
Published: April 2009

AbstractCyclooctyne smoothly underwent 1,3‐dipolar cycloaddition with pyridinium dicyanomethylides to afford the corresponding indolizines (8‐cyario‐7‐azatricyclo[7.6.0.02,7]pentadeca‐1,3,5,8‐tetraenes) in excellent yields.
Direct determination of pKa values of cationic acids conjugated to heterocyclic amine N‐oxides in polar aprotic and amphiprotic solvents
Authors: Chmurzyński Lech , Wawrzyniak Grażyna , Warnke Zygmunt , Pawlak Zenon 
Published: April 2009

AbstractThe applicability of the direct method of pKa determination in the case of protonated heterocyclic amine N‐oxides in a series of polar non‐aqueous (aprotic and amphiprotic) solvents has been tested. The method is based on the pH determination of the non‐aqueous solution of complex salt (the semiperchlorate in this case) formed by the N‐oxides studied. The direct method not only provides for quick (one data point per each pKa determined), but also relatively accurate estimates of acidic dissociation constants. It has been experimentally shown on the example of substituted pyridine N‐oxides that this method is precise enough in all studied non‐aqueous solvents when applied to compounds of not too low basicity (the pKa being of the order of 5 or higher). To prove this, the pKa values of protonated monocyclic N‐oxides obtained by the direct method have been compared with those resulting from the potentiometric titration curve. The agreement between the results found by using both methods is very good in most cases, the differences being within standard deviations. Based upon this observation it can be inferred that the pKa values of protonated bicyclic N‐oxides in solvents studied determined by using the direct method can be also considered reliable, especially in the case of polar aprotic solvents.
Intramolecular cyclization of amido acids into pyrrolidinothieno(or [1]benzothieno)[3]azepinediones
Authors: Othman Mohamed , Netchitailo Pierre , Decroix Bernard 
Published: April 2009

AbstractThe synthesis of pyrrolidino[2,1‐b]thieno[3,2(2,3)‐f][3]azepinediones 7a,b and pyrrolidino[2,1‐b]‐[1]benzothieno[3,2(2,3)‐f][3]azepinediones 7c,d are described starting from thiophenes or [1]benzothio‐phenes acetic acids. Their selective reduction using triethylsilane led to the corresponding azepinones 17a‐d.
Synthesis of certain alkenyl purines and purine analogs as inhibitors of tumor necrosis factor alpha (TNFα)
Authors: Rao T. Sudhakar , Ojwang Joshua O. , Marshall Hélène B. , Revankar Ganapathi R. 
Published: April 2009

AbstractThe preparation of 2‐penten‐1‐yl and 3‐methyl‐2‐buten‐1‐yl derivatives of adenine 2a,b, 7‐deazaadenine 2c,d, 2‐aminopurine 4a,b and 5a,b, 4‐aminopyrazolo[3,4‐d]pyrimidine 7a,b and 7‐amino‐v‐triazolo‐[4,5‐d]pyrimidine 8a–10a and 8b‐10b is described. The synthesis of compounds 2a‐d was accomplished by the functional group transformation reaction, whereas the synthesis of 4a‐8a and 4b‐8b was performed by the alkylation of the sodium salt of the heterocycles with alkenyl bromides. These alkenyl derivatives prepared as congeners of pentoxifylline (methylxanthine) were evaluated for their anti‐tumor necrosis factor a activity in human monocytic leukemia cells. Only compounds 7a and 7b exhibited significant activity and a poor toxicity profile in this assay. In peripheral blood mononuclear cells, compounds 7a and 7b, inhibited tumor necrosis factor a production in a dose dependent manner.
Alkyl 2‐(2‐benzoyl‐2‐ethoxycarbonyl‐1‐ethenyl)amino‐3‐dimethylaminopropenoates in the synthesis of heterocyclic systems
Authors: Strah Sonja , Stanovnik Branko , Grdadolnik Simona Golič 
Published: April 2009

AbstractAlkyl 2‐(2‐benzoyl‐2‐ethoxycarbonyl‐1‐ethenyl)amino‐3‐dimethylaminopropenoates 4a,b were prepared. They react with C‐nucleophiles such a 2‐pyridinylacetonitrile 5 and methyl‐2‐quinolinylacetate 8, cyclohexane‐1,3‐dione 10 and its derivatives 12 and 14, resorcinol derivative 16, 2‐naphtol 18, 2‐pyranone derivatives 20 and 22, and 4‐hydroxypyridin‐2(1H)‐one 24, to form substituted amino derivatives of quinolizine 6, benzo[c]quinolizine 9, tetrahydrobenzopyran‐2‐one 11, 13, 15, naphto[2,1‐b]pyran‐3‐one 19, pyranopyranones 21, 23, and pyrano[3,2‐c]pyridine 25.
Unusual sensitivity to the concentration of ethanol in the boron trifluoride/ethanol‐catalyzed synthesis of 5,10,15,20‐tetrakis‐(4‐cyano‐2,6‐dimethylphenyl)porphyrin by the lindsey method
Authors: Steiger Beat , Anson Fred C. 
Published: April 2009

AbstractThe boron trifluoride/ethanol‐catalyzed condensation of 4‐cyano‐2,6‐dtmethylbenzaldehyde 1b with pyrrole by the Lindsey method to give the new, ortho‐disubstituted 5,10,15,20‐tetrakis(4‐cyano‐2,6‐dimethylphenyl)porphyrin 2 was found to be highly sensitive to the concentration of ethanol. In the absence of ethanol the yield of porphyrin is only 1%. Yields can be increased to 20–25% with ethanol concentrations of 0.05–0.1% (v/v) but they decrease rapidly at higher concentrations of ethanol. Optimized procedures for the preparation of both 1b and 2 are described and the newly synthesized molecules are characterized by nmr (1H and 13C), mass spectra and elemental analysis.
Porphyrins with exocyclic rings. Part 8. Synthesis of nitrogen‐15 and carbon‐13 labeled 2,3:7,8:12,13:17,18‐tetrabutanoporphyrin
Authors: Chen Shaohua , Lash Timothy D. 
Published: April 2009

AbstractNitrogen‐15 labeled butyl 4,5,6,7‐tetrahydro‐2H‐isoindoIe‐1‐carboxylate was prepared via butyl iso‐cyanoacetate from 15N‐glycine in an overall 46% yield. This bicyclic intermediate was converted into nitrogen‐15 and carbon‐13 labeled 2,3:7,8:12,13:17,18‐tetrabutanoporphyrin, a useful model system for the sedimentary tetrahydrobenzoporphyrins.
A general synthetic route to 4‐substituted‐2,2′‐bithiophenes
Authors: Rasmussen Seth C. , Pickens Jason C. , Hutchison James E. 
Published: April 2009

AbstractA new synthetic route to 4‐substituted‐2,2′‐bithiophenes has been developed utilizing 4‐bromo‐2,2′‐bithiophene (1). Formation of the bithienyllithium adduct via halogen‐metal exchange was found to be problematic and resulted in complex mixtures of products. The Grignard reagent of 1 can be obtained easily via the “entrainment” method, allowing the production of 4‐substituted‐2,2′‐bithiophenes (where sub‐stituent = octyl, hydroxyethyl, hydroxymethyl, carboxy, carbomethoxy, acetoxyethyl, and acetoxymethyl).
Saturated heterocycles. 251. Determination of σ+ values of heteroaryl‐substituted phenyl groups via ring‐chain tautomerism
Authors: Fülöp Ferenc , Forró Enikö , Bernáth Gábor , Miskolczi István , Vainiotalo Pirjo , Martinsen Aarne 
Published: April 2009

AbstractThe Hammett‐Brown electrophilic substituent constants σ+ for five heteroaryl‐substituted phenyl groups were estimated via the ring‐chain tautomeric equilibria of three sets of oxazolidines and 1,3‐oxazines in deuteriochloroform solution. For oxazolidines derived from norephedrine and norpseudoephedrine, the σ+ values were also determined via the gas‐phase ring‐chain equilibria, by means of mass spectrometry. The results show that the heteroaromatic substituents studied have a slight electron‐withdrawing character, with σ+ in the range ‐0.03 to 0.59. The gas‐phase σ+ values are significantly higher than the solution values.
The complete 1H and 13C chemical shift assignments of a cyclopropylpyrroloindole analog: Adozelesin
Authors: Walker G. S. , Fagemess P. E. , Farley K. A. , Mizsak S. A. 
Published: April 2009

AbstractThe 1H and 13C nmr spectral assignments of [7bR]‐N‐[2‐[(4,5,8,8a‐tetrahydro‐7‐methyl‐4‐oxocyclo‐propa[c]pyrrolo[3,2‐e]indol‐2(1H)‐ylcarbonyl]‐1H‐indol‐5‐yl]‐2‐benzofurancarboxamide (Adozelesin) (1) are described. Complete and unambiguous assignments of the hydrogen and carbon spectra were made using a combination of conventional homonuclear and gradient‐selected inverse‐detected heteronuclear nmr experiments: double quantum filtered 1H‐1H correlation spectroscopy (COSY), gradient‐selected heteronuclear single quantum coherence spectroscopy (gs‐HSQC), and gradient‐selected heteronuclear multiple bond coherence spectroscopy (gs‐HMBC). The enhanced sensitivity of these experiments allowed a smaller sample concentration and shorter spectral collection times for a full nmr analysis of this compound. The nmr data corroborates the published structure of this compound.
Synthesis and binding properties of 2H‐1‐benzopyran‐2 one fluorophore‐linked calcium channel antagonist nifedipine (1,4‐dihydropyridine) analogs
Authors: Padmanabhan Seetharamaiyer , Peri Ravikumar , Rutledge Aleta , Triggle David J. 
Published: April 2009

AbstractNifedipine analogs I, II and III with the 2H‐1‐benzopyran‐2‐one (coumarin) fluorophore linked at the 2, 2 and 6 and 4 positions of the dihydropyridine ring were synthesized by the modified Hantzch condensation procedures. Attempts to synthesize dihydropyridine with the fluorophore at position 3 (IV) were unsuccessful.
13C‐NMR study on the tautomerism of 3‐(arylhydrazono)methyl‐2‐oxo‐1,2‐dihydroquinoxalines between the hydrazone imine and diazenylenamine forms
Authors: Kurasawa Yoshihisa , Takano Akiko , Kato Kyoko , Kim Ho Sik , Okamoto Yoshihisa 
Published: April 2009

AbstractThe 13C‐nmr study was carried out for the tautomerism of the 3‐(arylhydrazono)methyl‐2‐oxo‐1,2‐dihy‐droquinoxalines 1a‐g and 2a‐e between the hydrazone imine A and diazenylenamine B forms, providing the carbon chemical shifts for the tautomers A and B of compounds 1a‐g and 2a‐e. The comparison of the carbon chemical shifts for the tautomer B of compounds 1d, 1f, and 2b in deuteriodimethyl sulfoxide with those in deuteriotrifluoroacetic acid showed that the C4a, C5, and diazenyl carbons were considerably shielded presumably due to the azo N‐deuteration in deuteriotrifluoroacetic acid.
Synthesis of 6‐substituted 1‐alkoxy‐5‐alkyluracils
Authors: Kim Dae‐Kee , Kim Young‐Woo , Kim Key H. 
Published: April 2009

AbstractSynthesis of 6‐substituted 1‐alkoxy‐5‐alkyluracils 2a‐c have been achieved from readily accessible 2‐alkyl‐3,3‐di(methylthio)acryloyl chlorides 4a,b in high overall yields. Treatment of 4a,b with silver cyanate followed by reaction of the resulting isocyanates 5a,b with an appropriate alkoxyamine afforded N‐alkoxy‐N′‐[2‐alkyl‐3,3‐di(methylthio)acryloyl]ureas 6a,b in 85–88% yields. Cyclization of 6a,b in acetic acid containing methanesulfonic acid followed by oxidation with 3‐chloroperoxybenzoic acid gave high yields of 1‐alkoxy‐5‐alkyl‐6‐(methylsulfonyl)uracils 9a,b. Nucleophillic addition‐elimination reaction of 9a,b with sodium azide, phenylthiol, or phenylselenol produced 6‐azido‐1‐butoxythymine (2a, 98%), 5‐ethyl‐1‐(2‐phenoxyethoxy)‐6‐(phenylthio)uracil (2b, 95%), or 5‐ethyl‐1‐(2‐phenoxyethoxy)‐6‐(phenylselenenyl)uracil (2c, 91%).
Antimalarials: Synthesis of 4‐aminoquinolines that circumvent drug resistance in malaria parasites
Authors: De Dibyendu , Byers Larry D. , Krogstad Donald J. 
Published: April 2009

AbstractThe strategies described here have permitted the synthesis of a series of 4‐aminoquinoline antimalarials. Substantive improvements over previous syntheses include nucleophilic substitution with neat amine rather than in phenol, regioselective reductive alkylation to convert the terminal primary amine (12a–20a) on the diaminoalkane side chain to a diethylamino group, and purification by column chromatography with basic alumina. The 1H nmr spectra obtained after regioselective reductive alkylation with sodium borodeuteride (in comparison with sodium borohydride) demonstrated that this reductive alkylation proceeds via formation and subsequent reduction of the corresponding diamides in situ.
Selective, one‐pot synthesis of 2,3,6‐trisubstituted pyridine and 2‐cyclohexen‐1‐one derivatives from bicyclic ketals
Authors: Jun Jong‐Gab , Ha Tae Hee 
Published: April 2009

AbstractBoron difluoromethanesulfonate, prepared from 5 equivalents of trimethylsilyl methanesulfonate and 1 equivalent of boron trifluoride etherate, has proved to be an active Lewis acid catalyst for the one‐pot transformation reaction of bicyclic ketals in the 6,8‐dioxabicyclo[3.2.1]octane series to 2,3,6‐trisubstituted pyridine or 2‐cyclohexen‐1‐one selectively, depending on conditions. A 1,5‐diketone was the reaction intermediate for both products. Pyridine was formed selectively by using a nitrile as a solvent or a reagent, but cyclohexenone was prepared in methylene chloride instead of a nitrile.
Base promoted transformation on thiadiazolopyridinium chlorides
Authors: Martinez Ana , Castro Ana , Fayet J. P. 
Published: April 2009

Abstract1,2,4‐Thiadiazolo[2,3‐a]pyridinium chlorides undergo a very facile base promoted transformation to give bispyridilimino‐1,2,4‐thiadiazolidines. The unequivocal structural assignment of these last compounds was achieved by spectroscopic 1H, 13C and 15N two dimensional methods.