bluuebunny/crossref_metadata_2025_split huggingface dataset:
Steroidal imidazopyridines and lactam imidazopyridines
Authors: Nikolaropoulos Sotirios , Catsoulacos Panayotis 
Published: April 2009

AbstractCondensation of 17β‐acetoxy‐2α‐bromo‐5α‐androstan‐3‐one with unsubstituted and substituted amino‐pyridines, gives the corresponding 17β‐acetoxy‐5α‐androstanimidazo[1,2‐a]pyridines. Treatment of 16α‐bromo‐3‐aza‐A‐homo‐4α‐androsten‐4,17‐dione with 2‐aminopyridine or methyl‐2‐aminopyridine produces the corresponding 3‐aza‐A‐homo‐4α‐androsten[16,17:2′,3′]imidazo[1,2‐a]pyridines. Similarly, from 2α‐bromo‐17β‐acetamido‐5α‐androstan‐3‐one and methylaminopyridine the 17β‐acetamido‐5α‐androstan[2,3:2′,3′]imidazo[1,2‐a]methylpyridine has been obtained.The structure of the compounds was apparent from their chemical properties and spectral data (ir, uv and nmr).
Imidazolyl derivatives of the thiochroman ring
Authors: Cozzi Paolo , Pillan Antonio 
Published: April 2009

AbstractThe synthesis of 2‐(1H‐imidazol‐1‐yl)‐4H‐1‐benzothiopyran‐4‐ones 3 from 3‐bromo‐4H‐1‐benzothiopyran‐4‐ones 1 and imidazole is described. The reaction of 1 with secondary amines gives the corresponding 3‐amino‐thiochromones 11. Compounds 3 can be oxidized to the sulfones 4 from which the thiochromanols 5 and thiochromene 7 can be easily obtained. 3‐Bromo‐2,3‐dihydro‐6‐methyl‐4H‐1‐benzothiopyran‐4‐one 12 and imidazole led by dehydrohalogenation to thiochromone, while the ketal 13 rearranged to benzo[b]thiophene 16.
Investigation of the reactions of 2‐hydrazino‐benzimidazoles with β‐diketones: Synthesis of 2‐(3,5‐disubstituted‐ 1H‐pyrazol‐1‐yl)benzimidazoles
Authors: Joshi Krishna C. , Jain Renuka , Dandia Anshu , Sharma Kanti 
Published: April 2009

AbstractReaction of 2‐hydrazinobenzimidazoles with β‐diketones in neutral and acidic media revealed that 2‐(3,5‐disubstituted‐1H‐pyrazol‐1‐yi)benzimidazoles are formed in the former case, whereas hydrazones are obtained in acidic medium. Further the alkylation of > NH of the title compound was investigated. Characterisation of these products have been done by elemental analysis, ir, pmr, 19F nmr, 13C nmr and mass spectral studies.
Antimykotische wirkstoffe. XXI. Aliphatisch und alicyclisch substituierte chlor‐diallylamino‐1l,3,5‐triazine
Authors: Kreutzberger Alfred , Schläfer Irmtraut 
Published: April 2009

AbstractAus der nucleophilen Substitution eines Chloratoms in 2,4‐Dichlor‐6‐(diallylamino)‐1,3,5‐triazin (1) durch Amine (2a‐g) gehen die Alkylamino‐ und Cycloalkylamino‐chlor‐(diallylamino)‐1,3,5‐triazine (3a‐g) hervor. Von den zur Untermauerung des Strukturtyps 3 herangezogenen spektroskopischen Daten sind besonders charakteristisch die durch das 1,3,5‐Triazinringsystem hervorgerufene IR‐Bande bei 800 cm−1, die den Allylgruppen zuzuordnenden vier 1H‐NMR‐Signale zwischen 4,1–6,1 ppm und das beim massenspektroskopischen Abbau auftretende Rumpfkation m/e 158. Auffallend ausgeprägt sind in Verbindungsklasse 3 antimykotische, trichomonazide und herbizide Wirksamkeit.
Mannich reactions of heterocycles with dimethyl(methylene) ammonium chloride: A high yield, one‐step conversion of estazolam to adinazolam
Authors: Gall Martin , Kamdar Bharat V. , Lipton Michael F. , Chidester Connie G. , Duchamp David J. 
Published: April 2009

AbstractThe readily prepared ammonium salt, (CH3)2N+ = CH2Cl−, 4, functionalized heterocycles differently, but in a predictable fashion, under neutral, basic or acidic conditions. Triazolo‐ and imidazobenzophenones 1b′ and 5, which primarily underwent intramolecular isomerization to indolols 2a′ and 6a rather than intermolecular electrophilic substitution under conditions of the normal aqueous Mannich reaction, were converted with 4 to the desired benzophenone derivatives, 1c′ and 7, respectively, in moderate yields. The 1‐unsubstituted triazolo‐ or imidazobenzodiazepines, 10a (estazolam) and 10b, were transformed to the corresponding 1‐(dimethylamino)methyl derivatives, 11a (adinazolam) and 11b, in good to moderate yields (61% and 32%, respectively.) Under acidic reaction conditions, 1‐methyl triazolobenzodiazepine, 10d (alprazolam), afforded 12e, the product of attack at C‐4 of the triazolo[4,3‐a][1,4]benzodiazepine ring system. Under strongly basic conditions in which the anion of 10d was generated prior to reaction with 4, both 12e and its isomer, 15, were formed. These results complement the report that 4 may be used to functionalize the 1‐methyl position of triazolobenzodiazepines, and further demonstrate the versatility of reagent 4 in heterocyclic synthesis.
Synthesis of 2‐hetaryl‐6H‐pyrazolo[3,4‐d]‐1,2,3‐triazoles
Authors: Rangnekar D. W. , Dhamnaskar S. V. 
Published: April 2009

AbstractA novel efficient synthesis of 2‐hetaryl‐4‐methyl‐6‐phenyl‐6H‐pyrazolo[3,4‐d]‐1,2,3‐triazoles was achieved by the reaction of 5‐amino‐3‐methyl‐4‐nitroso‐1‐phenyl‐1H‐pyrazole with heterocyclic amines followed by air oxidation in the presence of cupric acetate.
1,3‐Dipolar cycloadditions of azomethine ylides with dipolarophiles. II. Synthesis of pyrrolizidines
Authors: Orsini F. , Pelizzoni F. , Forte M. , Sisti M. , Merati F. , Gariboldi P. 
Published: April 2009

AbstractSubstituted pyrrolizidines have been synthesized by 1,3‐dipolar cycloaddition of various dipolarophiles with the azomethine ylide generated by treatment of proline with benzaldehyde in dimethylsulfoxide. The regio‐ and stereochemical outcome of the reaction as well as the stability of the isomers obtained are discussed.
2‐(methylpyridyl)‐X‐azolo[4,5‐b]pyridines: Bases, salts and polymethine dyes
Authors: Savarino Piero , Carpignano Rosarina , Viscardi Guido , Barni Ermanno , Di Modica Gaetano 
Published: April 2009

AbstractA series of heterocyclic bases containing 2‐(methyl‐3‐pyridyl)‐X‐azolo[4,5‐b]pyridine was synthesized and the obtained bases were then quaternized. The structures of the salts were assessed by nmr and uv spectroscopy. From quaternary salts, styryl dyes were prepared and similarly characterized. The physical and spectroscopic data of the compounds were compared with those of other isomers, previously described, and of the corresponding benzo‐X‐azole derivatives.
4‐Diazomethylcoumarins and related stable heteroaryldiazomethanes. Thermal conversion into condensed pyrazoles
Authors: Ito Keiichi , Maruyama Junko 
Published: April 2009

Abstract4‐Diazomethyl‐substituted coumarins, 1‐methyl‐2(1H)‐quinolinones,1‐thiocoumarin and their tricyclic analogs were found to be easily cyclized into the corresponding pyrazole isomers condensed with heteroaromatics. Thermodependent feature of these conversions and the remarkably accelerating effect of the alkyl substituent peri to the diazomethyl group were realized. Some other diazomethyl compounds connected with 2‐pyridinone, 3‐pyrazolone, chromone and 1‐thiochromone were prepared, and their stability and thermal properties were compared.
6‐(substituted phenyl)‐5‐methyl‐4,5‐dihydro‐pyridazin‐3(2H)‐ones of medicinal interest. The synthesis of SK&F 94836 and SK&F 95654
Authors: Burpitt B. E. , Crawford L. P. , Davies B. J. , Mistry J. , Mitchell M. B. , Pancholi K. D. , Coates W. J. 
Published: April 2009

AbstractTwo synthetic routes to the dihydropyridazinone‐cyanoguanidine 4 (SK&F 94836) are described, both proceeding via the anilino compound 6. An efficient synthesis of the dihydropyridazinone‐pyridone 5 (SK&F 95654) is reported. This synthesis proceeds via the fluoro‐keto‐acid 24, with subsequent displacement of the fluoro substituent by 4‐pyridone. The surprising effectiveness of water as a solvent in this reaction has been highlighted.
Amidomethylation of phenanthridines: Synthesis and structure determination by 1H NMR
Authors: Freter K. R. , Grözinger K. G. , Kriwacki R. W. 
Published: April 2009

AbstractPhenanthridine reacts with N‐(hydroxymethyl)phthalimide to give, in two steps, three monosubstituted aminomethylphenanthridines. The three isomers were separated by chromatography on silica gel. The position of substitution was determined using one‐ and two‐dimensional 1H nmr methods.
Preparation and characterization of nickel(II), copper(II) and palladium(II) complexes with 5,14‐dihydro‐7,16‐diethyl‐dipyrazo[b,i][1,4,8,11]tetraazacyclotetradecine
Authors: Hashimoto Mamoru , Izuchi Nobuko , Sakata Kazunori 
Published: April 2009

AbstractA novel macrocycle, 5,14‐dihydro‐7,16‐diethyldipyrazo[b,i][1,4,8,11]tetraazacyclotetradecine, has been synthesized from 1,2‐diaminopyrazine and 2‐ethyl‐3‐ethoxyacrolein. The absorption bands appearing in the energy range greater than 20000 cm−1 were attributable to the π → π transitions. The bands in the range of the 20100–23300 cm−1 show more bathochromic shift and greater intensity than those observed for corresponding 5,14‐dihydro‐7,16‐diethyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecine and/or 5,14‐dihydro‐7,16‐diethyl‐(Z)‐dipyrido[b,i][1,4,8,11]tetraazacyclotetradecine. The nickel(II), copper(II) and palladium(II) complexes of 5,14‐dihydro‐7,16‐diethyldipyrazo[b,i][1,4,8,11]tetraazacyclotetradecine have been synthesized using a metal template reaction. In 1H and 13C nmr spectra, the signals of annulene skeleton for metal‐free ligand and its complexes were found to observe in the lower field than those of the dibenzoanalogue.
Pyridazines with heteroatom substituents in position 3 and 5. 2. Regioselective introduction of mercapto groups in pyridazines
Authors: Olesen Preben H. , Kappe Thomas , Becher Jan 
Published: April 2009

AbstractThe nucleophilic substitution of halogen in 3,5‐dichloro‐6‐phenylpyridazine 1, 5‐chloro‐2‐methyl‐6‐phenylpyridazin‐3(2H)‐one 13 as well as in 3‐chloro‐2‐methyl‐6‐phenylpyridazin‐5(2H)‐one 14 with methoxy, ethoxy and the 2‐methyl‐2‐propanethiolate anion is described. In the last type of compounds the t‐butylthio groups can be eliminated regioselectively with Lewis acids, resulting in the formation of monomercapto and mono‐thiopyridazines.
Benzimidazole condensed ring systems. 2. New synthesis of substituted 1‐oxo‐1H,5H‐pyrido[1,2‐a]benzimidazole‐4‐carbonitriles and related derivatives
Authors: Rida Samia M. , Soliman Farid S. G. , Badawey El‐Sayed A. M. , Kappe Thomas 
Published: April 2009

AbstractThe synthesis of some 3‐substituted and 2,3‐disubstituted‐1‐oxo‐1H,5H‐pyrido[1,2‐a]benzimidazole‐4‐carbo‐nitriles 5,6 by fusing 1H‐benzimidazole‐2‐acetonitrile 1 with some β‐keto esters 2,4 in the presence of ammonium acetate or with ethyl β‐aminocrotonate 3 is described. The tricyclic compounds were converted to their N‐5 methyl of N‐5 ethyl derivatives 8,9. Vilsmeir‐Haack formylation of 3‐methyl‐1‐oxo‐1H,5H‐pyrido[1,2‐a]‐benzimidazole‐4‐carbonitrile 5a afforded its 2‐formyl derivative 10. Chlorination of 5 and 6 with phosphorus oxychloride yielded the respective 1‐chloropyrido[1,2‐a]benzimidazole‐4‐carbonitriles 11,12 which were utilized to prepare the 1‐azido, 1‐amino, 1‐piperidino and 1‐methoxy derivatives of the ring system. Compound 11a exhibited strong in vitro activity against S. aureus. Four compounds were screened against P‐388 lymphocytic leukemia in mice but were inactive.
Synthesis of N(3‐dimethylaminopropyl)‐6‐substituted naphtho[2,1‐b]thiophene‐4‐carboxamides
Authors: Ming Yang , Boykin David W. 
Published: April 2009

AbstractA series of N‐(3‐dimethylaminopropyl)‐6‐substituted naphtho[2,1‐b]thiophenes‐4‐carboxamides have been synthesized. 6‐Substituted naphtho[2,1‐b]thiophene‐4‐carboxylic acids were obtained upon oxidative‐photo‐cyclization of α‐(2‐thienyl)‐β‐arylacrylic acids. The naphtho[2,1‐b]thiophene carboxylic acids were converted to the corresponding amides through their acid chlorides or, in one case, by use of 1,1‐carbonyldiimidazole coupling of the amine and the acid.
Synthesis of 2‐amino‐6,7‐dihydrothieno‐[3′,2′:5,6]pyrido[2,3‐d]pyrimidin‐4‐one
Authors: Taylor Edward C. , Pont Joseph L. , Warner John C. 
Published: April 2009

Abstract2‐Amino‐6,7‐dihydrothieno[3′,2′:5,6]pyrido[2,3‐rf]pyrimidin‐4‐one (1) was prepared in three steps from S‐(3‐butynyl)thiosemicarbazide hydroiodide (3) and diethyl ketomalonate. The featured step in this synthetic sequence was an intramolecular Diels‐Alder reaction of the in situ generated 3‐(3‐butynylthio)‐6‐carboethoxy‐5‐chloro‐1,2,4‐triazine (9) to provide the key intermediate 5‐carboethoxy‐6‐chloro‐2,3‐dihydrothieno‐[2,3‐b]pyridine (6). In the course of studies directed toward the preparation of 1, thermolysis of 3‐(3‐butynyl‐thio)‐6‐carboethoxy‐1,2,4‐triazin‐5(2H)‐one (2) was found to involve competitive intramolecular Diels‐Alder and intramolecular coplanar cycloamination processes, providing the 2,3‐dihydrothieno[2,3‐b]pyridin‐6(7H)‐one (4) and the 1,3‐thiazino[3,2‐b]‐1,2,4‐triazin‐3‐one (5) derivatives, respectively.
Difference in thermal behaviour between 1‐ and 2‐alkyl‐5‐(methoxycarbonyldiazomethyl)tetrazoles
Authors: L'Abbé Gerrit , Gelinne Marleen , Toppet Suzanne 
Published: April 2009

AbstractIn continuation of previous work, isomeric diazoester‐substituted alkyltetrazoles 5 and 6 have been synthesized by the diazo‐transfer method and studied in thermolysis reactions. Whereas the N‐1 alkyl derivatives 5 give norcaradienes 7 in benzene solution and imidazotetrazoles 12 in acetonitrile, the more thermostable N‐2 alkyl isomers 6 yield fluxional norcaradiene‐cycloheptatriene systems, 10 – 11, and ox‐azoles 13.
The reaction of 2‐substituted‐4,5‐dichloro‐3(2H)‐pyridazinones with alkoxides and alkylthiolates
Authors: Lyga John W. 
Published: April 2009

AbstractThe reaction of 2‐substituted‐4,5‐dichloro‐3(2H)‐pyridazinones 1a‐b with alkoxides and alkylthiolates was investigated. Regiospecific displacement of either the 4 or 5 chlorine atom could be achieved in most cases by appropriate selection of the reaction solvent.
A convenient one pot synthesis of substituted 4‐aminobenzopyrano[3,4‐c]pyridinones
Authors: Rangnekar D. W. , Dhamnaskar S. V. 
Published: April 2009

AbstractA new synthesis of substituted 4‐aminobenzopyrano[3,4‐c]pyridinones was achieved in one pot by the condensation of an o‐hydroxyaraldehyde and a cyclic or acylic methyl ketone in the presence of ammonium acetate in refluxing ethanol followed by the treatment of malononitrile and subsequent hydrolysis with hydrochloric acid in situ.
Synthesis of a novel tricyclic 4‐quinolone. Incorporation of a spiro‐cyclopropyl group at N1 by bridging to C2
Authors: Schroeder Mel C. , Kiely John S. 
Published: April 2009

AbstractAn important pharmacophore in many quinolone antiinfectives is the N1 cyclopropane. By incorporating the cyclopropane into a N1 to C2 bridge, the first quinolone substrate incorporating a spiro fused cyclopropane, 8,9,10‐trifluoro‐2,3,4,6‐tetrahydro‐6‐oxospiro[1H‐benzo[c]quinolizine‐1,l‐cyclopropane]‐5‐carboxylic acid, ethyl ester (8), was prepared.
A stereochemical investigation of 1,3‐diphenyl‐4‐methyl‐1,3‐diazolidines and its related compounds via NMR
Authors: Nishiyama Tomihiro , Nanno Yukio , Yamada Fukiko 
Published: April 2009

AbstractFour 1,3‐diphenyl‐4‐methyl‐1,3‐diazolidines and two isomeric 2,5‐diphenyl‐3‐methyl‐1,2,5‐thiadiazolidine 2‐oxides were prepared. The pmr and cmr spectra of these compounds were obtained. On the basis of the chemical shifts due to the γ and δ‐effects, the Stereochemical structures are discussed.
Synthesis and reactions of 1,2‐fused 3‐cyanoindolizines
Authors: Matsumoto Kiyoshi , Uchida Takane , Aoyama Kinuyo , Nishikawa Masahiko , Kuroda Takeshi , Okamoto Tadashi 
Published: April 2009

AbstractWith the intention that annulation of carbo‐ or heteroaromatic rings at the 1,2‐positions can activate 3‐cyanoindolizines as 1,3‐dipolar species, 6‐cyanobenz[a]indolizines, pyridazino[4,5‐a]indolizines and 5‐cyano‐1,3‐diphenylthiopheno[3,4‐a]indolizine were prepared. 6‐Cyanobenz[a]indolizines smoothly ‐underwent 1,3‐dipolar cycloaddition on to dibenzoylacetylene and diacetylacetylene to afford the corresponding indolizino[3,4,5‐ab]isoindoles, whereas 5‐cyano‐1,4‐diphenylpyridazino[4,5‐a]indolizine reacted with dimethyl acetylenedicarboxylate to give the 1:2 adduct. Only a 3% yield of 5‐cyano‐1,3‐diphenylthiopheno[3,4‐a]indolizine formed upon phosphorus pentasulfide treatment of 1,2‐dibenzoyl‐3‐cyanoindolizine.
Reactions of 3‐hydrazino‐5,6‐diphenyl‐1,2,4‐triazine with 4‐arylidene‐2‐phenyl‐5(4H)‐oxazolones and 4‐benzylidene‐3‐methyl‐5(4H)‐isoxazolone
Authors: Eid Mohga M. , Badawy M. A. , Mansour A. K. 
Published: April 2009

Abstract3‐Hydrazino‐5,6‐diphenyl‐1,2,4‐triazine reacts with 4‐arylidene‐2‐phenyl‐5(4H)‐oxazolones in toluene to give substituted acrylic acid hydrazides, and in glacial acetic acid to give substituted imidazolones. On the other hand the hydrazinotriazine reacts with 4‐benzylidene‐3‐methyl‐5(4H)‐isoxazolone, probably via a 1,4 addition reaction followed by an elimination reaction, to give benzaldehyde 5,6‐diphenyl‐1,2,4‐triazin‐3‐ylhydrazone and 3‐methyl‐5(4H)‐isoxazolone.
Entzündungshemmende wirkstoffe. XI. Ringschlußreaktion an 5‐phenyl‐2‐thiobiuret
Authors: Kreutzberger Alfred , Daus Silva 
Published: April 2009

AbstractDie Umsetzung von 5‐Phenyl‐2‐thiobiuret (1) mil α‐Chlorcarbonylverbindungen 2 führt zu den N‐Phenyl‐N′‐(2‐thiazolyl)harnstoffen (3). Unter den neuen Verbindungen finden sich besonders die entzundungshemmende, anthelminthische und trichomonazide Wirksamkeit stark ausgeprägt.
A one step synthesis of 4‐substituted imidazoles. An important observation when N‐alkylating imidazoles
Authors: Whitten Jeffrey P. , Matthews Donald P. , Mccarthy James R. , Barbuch Robert J. 
Published: April 2009

AbstractImidazoles substituted in the 2‐position with methyl, 1e, phenyl, 1a, 2‐imidazole, 1b‐d, or t‐butyldiphenylsilyl, If, react with soft electrophiles 2 to give modest yields of 4(5)‐C‐alkylated‐imidazoles 3 and N‐alkylated products 5. These two products are readily separated by flash chromatography.
Synthesis and single‐crystal X‐ray diffraction studies of 1‐β‐D‐ribofuranosyl‐1,2,4‐triazole‐3‐sulfonamide and certain related nucleosides
Authors: Hanna Naeem B. , Dimitrijevich Slobodan D. , Larson Steven B. , Robins Roland K. , Revankar Ganapathi R. 
Published: April 2009

Abstract1‐β‐D‐Ribofuranosyl‐ 21, 1‐(2‐deoxy‐β‐D‐erytftro‐pentofuranosyl)‐ 27 and 1‐β‐D‐arabinofuranosyl‐ 29 derivatives of 1,2,4‐triazole‐3‐sulfonamide (19) have been prepared. Glycosylation of the silylated 19 with 1,2,3,5‐tetra‐0‐acetyl‐β‐D‐ribofuranose (5) in the presence of trimethylsilyl triflate gave the corresponding blocked nucleoside (20), which on ammonolysis afforded 1‐β‐D‐ribofuranosyl‐1,2,4‐triazole‐3‐sulfonamide (21). Stereospecific glycosylation of the sodium salt of 19 with either 1‐chloro‐2‐deoxy‐3,5‐di‐O‐p‐toluoyl‐α‐D‐erythro‐pentofuranose (22) or 1‐chloro‐2,3,5‐tri‐0‐benzyl‐α‐D‐arabinofuranose (23) provided the corresponding protected nucleosides 26 and 28. Deprotection of 26 and 28 furnished 1‐(2‐deoxy‐β‐D‐erythro‐pentofuranosyl)‐1,2,4‐triazole‐3‐sulfonamide (27) and 1‐β‐D‐arabinofuranosyl‐1,2,4‐triazole‐3‐sulfonamide (29), respectively. 2‐0‐D‐Ribofuranosyl‐1,2,4‐triazole‐3(4H)‐thione (7) and 4‐β‐D‐ribofuranosyl‐1,2,4‐triazole‐3(2H)‐thione (9) were also prepared utilizing either an acid catalyzed fusion of 1,2,4‐triazole‐3(1H,2H)‐thione (4) with 5, the reaction of 5 with silylated 4 in the presence of trimethylsilyl triflate, or by ring closure of 4‐(2,3,5‐tri‐0‐benzoyl‐β‐D‐ribofuranosyl)thiosemicarbazide (10) with mixed anhydride and subsequent deacylation. The synthesis of 1‐β‐D‐ribofuranosyl‐3‐benzylthio‐1,2,4‐triazole (15) has also been accomplished by the silylation procedure employing 3‐benzylthio‐1,2,4‐triazole (13) and 5 to give 1‐(2,3,5‐tri‐0‐acetyl‐β‐D‐ribofuranosyl)‐3‐benzylthio‐1,2,4‐triazole (14). Deacetylation of 14 furnished 15. The structural assignments of 7, 14 and 21 were made by single‐crystal X‐ray diffraction analysis and their hydrogen bonding characteristics have been studied. The sulfonamido‐1,2,4‐triazole nucleosides are devoid of any significant antiviral or antitumor activity in cell culture.
A facile and improved synthesis of tubercidin and certain related pyrrolo[2,3‐d]pyrimidine nucleosides by the stereospecific sodium salt glycosylation procedure
Authors: Ramasamy Kandasamy , Imamura Nobutaka , Robins Roland K. , Revankar Ganapathi R. 
Published: April 2009

AbstractA simple synthesis of tubercidin (1), 7‐deazaguanosine (2) and 2′‐deoxy‐7‐deazaguanosine (14) has been accomplished using the sodium salt glycosylation procedure. Reaction of the sodium salt of 4‐chloro‐ and 2‐amino‐4‐chloro‐pyrrolo[2,3‐d]pyrimidine, 3 and 4, respectively, with 1‐chloro‐2,3‐0‐isopropylidene‐5‐0‐(t‐butyl)dimethylsilyl‐α‐D‐ribofuranose (5) gave the corresponding protected nucleosides 6n and 7 with β‐anomeric configuration. Deprotection of 6 provided 8, which on heating with methanolic ammonia gave tubercidin (1) in excellent yield. Functional group transformation of 7, followed by deisopropylidenation gave 2‐aminotubercidin (10) and 2‐amino‐7‐β‐D‐ribofuranosylpyrrolo[2,3‐d]pyrimidine‐4(3H)‐thione (11). Treatment of 7 with 1N sodium methoxide followed by exposure to aqueous trifluoroacetic acid, and ether cleavage furnished 7‐deazaguanosine (2). 2′‐Deoxy‐7‐deazaguanosine (14) and 2′‐deoxy‐7‐deaza‐6‐thioguano‐sine (18) were also prepared by using similar sequence of reactions employing 4 and 1‐chloro‐2‐deoxy‐3,5‐di‐O‐p‐toluoyl‐α‐D‐erythro‐pentofuranose (15).
A convenient synthesis of 2′‐deoxy‐6‐thioguanosine,ara‐guanine,ara‐6‐thioguanine and certain related purine nucleosides by the stereospecific sodium salt glycosylation procedure
Authors: Hanna Naeem B. , Ramasamy Kandasamy , Robins Roland K. , Revankar Ganapathi R. 
Published: April 2009

AbstractA simple and high‐yield synthesis of biologically significant 2′‐deoxy‐6‐thioguanosine (11),ara‐6‐thioguanine (16) andaraG (17) has been accomplished employing the Stereospecific sodium salt glycosylation method. Glycosylation of the sodium salt of 6‐chloro‐ and 2‐amino‐6‐chloropurine (1and2, respectively) with 1‐chloro‐2‐deoxy‐3,5‐di‐O‐(p‐toluoyl)‐α‐D‐erythro‐pentofuranose (3) gave the corresponding N‐9 substituted nucleosides as major products with the β‐anomeric configuration (4and5, respectively) along with a minor amount of the N‐7 positional isomers (6and7). Treatment of4with hydrogen sulfide in methanol containing sodium methoxide gave 2′‐deoxy‐6‐thioinosine (10) in 93% yield. Similarly,5was transformed into 2′‐deoxy‐6‐thioguanosine (β‐TGdR,11) in 71 % yield. Reaction of the sodium salt of2with 1‐chloro‐2,3,5‐tri‐O‐benzyl‐α‐D‐arabinofuranose (8) gave N‐7 and N‐9 glycosylated products13and9, respectively. Debenzylation of9with boron trichloride at −78° gave the versatile intermediate 2‐amino‐6‐chloro‐9‐β‐D‐arabinofuranosyl‐purine (14) in 62% yield. Direct treatment of14with sodium hydrosulfide furnishedara‐6‐thioguanine (16). Alkaline hydrolysis of14readily gave 9‐β‐D‐arabinofuranosylguanine (araG,17), which on subsequent phosphorylation with phosphorus oxychloride in trimethyl phosphate affordedaraG 5′‐monophosphate (18).
Synthesis of some heterocyclic skeletons via organoiron complexes. Crystal and molecular structure of (5a,6,7,8,9,9a‐η6‐1,4‐benzoxathiino[3,2‐b]pyridine)(η5‐cyclopentadienyl)iron hexafluorophosphate
Authors: Sutherland Ronald G. , Piórko Adam , Lee Choi Chuck , Simonsen Stanley H. , Lynch Vincent M. 
Published: April 2009

AbstractSynthesis of the heterocyclic skeletons of some biologically active compounds from (η6‐o‐dichlorobenzene)(η5‐cyclopentadienyrl)iron hexafluorophosphate in a two step procedure is described. Cyclopentadienyliron hexafluorophosphate complexes of 1,4‐benzodioxino[2,3‐b]pyridine, 1,4‐benzoxathiino[3,2‐b]pyridine, 10H‐pyrido[3,2‐b]benzoxazine, benzo[b]naphtho[2,3‐e][1,4]dioxin, 4‐methylbenzo[b]benzopyran‐2‐one[7,6‐e][1,4]dioxin and benzo[b]anthracen‐9,10‐diono[1,2‐e][1,4]dioxin were isolated and characterized. Upon pyrolytic sublimation of these complexes the free heterocycles were obtained and characterized. (η6‐1,4‐Benzoxathiino[3,2‐b]pyridine)(η5‐cyclopentadienyl)iron hexafluorophosphate crystalizes in the orthothombic system, space group Pbca; the dihedral angle between the planes of outer rings was found to be 176.8 (1).