bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of 4(5)‐hydroxymethylimidazoles by hydroxymethylation and decarboxylation of imidazole‐4(5)‐carboxylic acids
Authors: Kim Choong S. , Lee Kee J. , Kim Hong S. , Chae Yung B.
Published: March 2009

4(5)‐Hydroxymethylimidazoles were prepared by hydroxymethylation and decarboxylation of imidazole‐4(5)‐carboxylic acid esters. The reaction was simply carried out with aqueous formaldehyde solution in the presence of base.
A new synthesis of naphtho[2,3‐C]pyrroles. Conversion of naphtho[2,3‐C]thiophene‐4,9‐diones to naphtho[2,3‐C]pyrrole‐4,9‐diones
Authors: Marecki Paul E. , Butke Gregory P.
Published: March 2009

A series of 2‐substituted‐4,9‐dihydronaphtho[2,3‐c]pyrrole‐4,9‐diones was prepared by the reaction of 4,9‐dihydronaphtho[2,3‐c]thiophene‐4,9‐diones with primary amines under mild conditions. The presence of halogen in the naphtho[2,3‐c]thiophene‐4,9‐dione and the presence of hydroxyl, ether, or tertiary amine functions in the amine reagent do not interfere with the course of the reaction.
Furan derivatives. Part 8 On substituent effects in the synthesis of 4,5‐dihydro‐3H‐naphtho[1,8‐bc]furans
Authors: Horaguchi Takaaki , Yagoh Hiroaki , Tanemura Kiyoshi , Suzuki Tsuneo
Published: March 2009

4,5‐Dihydro‐3H‐naphtho[1,8‐bc]furans 4 and 6 which have various substituents (R1 and R2) have been synthesized from 8‐oxo‐5,6,7,8‐tetrahydro‐1‐naphthyloxyacetic acids 1 and 3 or their ethyl esters 2. The reaction of acids 1 and 3 with sodium acetate in acetic anhydride gave a mixture of furans 4 and 6 and lactones 5 and 7. The ratios of the products were varied according to the types of substituents (R1 and R2) in acids 1 and 3. As the substituent R1 (R2 = hydrogen) in acids 1 was changed from hydrogen to a methyl, ethyl or isopropyl group, production of furans 4 became more difficult. However, when a phenyl group was used as the substituent, furan 4 was obtained in good yield. Similarly, as the substituent R2 (R1 = hydrogen) in acids 1 was changed from hydrogen to a methyl, ethyl or isopropyl group, furan formation was more difficult. In contrast, acids 3 which had electron‐withdrawing substituents such as chlorine, bromine or a nitro group at the 4‐position afforded furans 6 in good yield. 4,5‐Dihydro‐3H‐naphtho[1,8‐bc]furans 4 and 4,5‐dihydro‐3H‐naphtho[1,8‐bc]furan‐2‐carbocylic acids 8 were synthesized from the reaction of esters 2 and potassium hydroxide in dioxane. When the substituents R1 or R2 in esters 2 were varied from hydrogen to a methyl, ethyl or isopropyl group the total yields of furans 4 and furancarboxylic acids 8 were reduced.
Synthesis and acylation of 2‐nitro‐11H‐dibenzo[b,e][1,4]dioxepin
Authors: Hagmann William K. , O'Grady Laura A. , Dorn Conrad P. , Springer James P.
Published: March 2009

A one‐pot synthesis of the 11H‐dibenzo[b,e]1,4]dioxepin ring system from catechol and an o‐chlorobenzyl chloride is described. Friedel‐Crafts acylation occurs at the 7‐position as shown by X‐ray analysis.
Annelated derivatives of 2‐phenylquinoline, 2‐(2′‐pyridyl)quinoline and 2‐phenyl‐1,8‐naphthyridine
Authors: Thummel Randolph P. , Decloitre Yves , Lefoulon Francois
Published: March 2009

Annelated derivatives of 2‐phenylquinoline, 2‐(2′‐pyridyl)quinoline, and 2‐phenyl‐1,8‐naphthyridine have been prepared where the bridging unit contains from one to four methylene units. The conformational properties of these molecules have been analyzed by 1H nmr and uv spectroscopy as well as by pKa determinations.
The benzoin condensation catalysis by bis(azolin‐2‐ylidene)s and bis(azolidin‐2‐ylidene)s and its interpretation within the context of nucleophilic carbene chemistry
Authors: Castells J. , López‐Calahorra F. , Geijo F. , Pérez‐Dolz R. , Bassedas M.
Published: March 2009

The preparation of bis(thiazolin‐2‐ylidene)s by passing a methanol solution of the corresponding thiazolium salt through an ion exchange column (basic form) is reported and the use of these “dimers” as benzoin condensation catalysts is studied. The “dimers” show better catalytic activity than the corresponding thiazolium salt plus base. A general discussion of the benzoin condensation catalysis within the framework of nucleophilic carbene chemistry is carried out and as a result of it the important role played by the “dimers” is emphasized. Mechanistic suggestions related with this fact are put forward.
Polycondensed heterocycles. II. A new preparative route to 11‐Oxo‐5H,11H‐pyrrolo[2,1‐c][1,4]benzothiazepine
Authors: Nacci V. , Garofalo A. , Fiorini I.
Published: March 2009

6‐Methylthio‐10‐oxo‐5H,10H‐pyrrolo[1,2‐b]isoquinoline 11 was isolated in an attempted synthesis of 11‐oxo‐5H,11H‐pyrrolo[2,1‐c][1,4]benzothiazepine 1 from 1‐(2‐methylthiobenzyl)pyrrole‐2‐carboxylic acid chloride 9, obtained using as starting material o‐methylthiobenzyl bromide 3 and passing through 1‐(2‐methylthiobenzyl)pyrrole‐2‐carbonitrile 5, by cyclization with aluminum chloride. However the successful demethylation with sodium in dimethylacetamide of 1‐(2‐methylthiobenzyl)pyrrole‐2‐carboxyamide 12, formed by hydrolysis of nitrile 5, allowed us to prepare by another way the corresponding thiol 13 and consequently the 1‐(2‐mercaptobenzyl)pyrrole‐2‐carboxylic acid 14, which when subjected to intramolecular ring closure by CDI in place of DCC gave 1 in higher yield, 69% instead of 43%. Finally, the direct cyanation of 1‐(2‐ethoxycarbonylthiobenzyl)pyrrole 16, prepared utilizing the 1‐(2‐mercaptobenzyl)pyrrole 15 obtained by demethylation of the corresponding thioanisol 4 which was carried out as above, afforded the unexpected 1‐(2‐ethylthio‐benzyl)pyrrole‐2‐carbonitrile 17.
The insertion and extrusion of heterosulfur bridges. XVI. Synthesis of triphenyleno[1,12‐bcd:4,5‐b'c'd']dithiophene
Authors: Klemm L. H. , Hall Eliot , Cousins Lisa , Klopfenstein C. E.
Published: March 2009

Triphenyleno[1,12‐bcd]:4,5‐b′c′d′]dithiophene (3) is synthesized in low yield (2.5% maximum) from a mixture of triphenylene (1) and triphenyleno[4,5‐bcd]thiophene or from 1 alone by means of heterogeneously catalyzed sulfur bridging by hydrogen sulfide at 500–550°. Compound 3 is characterized by spectral and other properties. Hückel molecular orbital calculations for the formation and reaction of 3 are presented.
Regio‐ and stereoselectivity of cycloadditions of C‐(Trifluoromethyl)nitrone with olefins
Authors: Tanaka Kiyoshi , Sugimoto Yasuhiko , Okafuji Yoshiaki , Tachikawa Masahiro , Mitsuhashi Keiryo
Published: March 2009

N‐Methyl‐C‐(trifluoromethyl)nitrone (1) cycloadds with various olefins to give 2‐methyl‐3‐trifluoromethyl‐isoxazolidines. Predominant formation of 5‐substituted isoxazolidines in the cycloadditions with monosubstituted olefins is observed and this high regioselectivity is attributed to the dipole‐LUMO controlled interaction, being rationalized on the basis of molecular orbital calculation of 1. ‘Anti’‐favorable approach of 1 to olefin in the transition state is considered from the configuration of the cycloadducts, pointing out the very weak secondary orbital interaction between trifluoromethyl group and olefin‐substituents including phenyl or ester group.
Synthesis of some benzimidazole‐, pyridine‐ and imidazole‐derived chelating agents
Authors: Wahlgren Curtis G. , Addison Anthony W.
Published: March 2009

Procedures are described for the preparation of various bidentate and potentially tridentate chelating agents. These incorporate pyridyl, benzimidazole, imidazole or phenolic moieties. Phillips condensations of carboxylic acids with o‐phenylenediamines were carried out in 4 M hydrochloric acid. Syntheses are reported for 2, 6‐bis(N′‐methylimidazol‐2′‐ylthiomethyl)pyridine, 2, 6‐bis(benzimidazol‐2′‐ylthiomethyl)pyridine, 2‐(4′‐piperidyl)benzimidazole, 2‐(3′‐piperidyl)benzimidazole, 2‐(3‐N′‐methylpiperidyl)benziinidazole, 2‐(3‐N′‐methylpiperidyl)‐N‐methylbenzimidazole, 2‐(2′‐hydroxybenzyl)benzimidazole and 2‐(2′‐hydroxyben‐zyl)N‐methylbenzimidazole. The compounds were characterized where appropriate by their mass, uv, and 1H‐nmr spectra. 2‐(2′‐Hydroxybenzyl)benzimidazole hydrochloride acts as a gelling agent in aqueous solution.
On pyrrolidine derivatives I. An efficient synthesis of 3‐substituted (2S,5S)‐pyrrolidine‐2, 5‐dicarboxylic acids
Authors: Honma Tsunetoshi , Tada Yukio , Adachi Ikuo , Igarashi Kikuo
Published: March 2009

(2S,5S)‐3‐Alkylpyrrolidine‐2, 5‐dicarboxylic acid derivatives I were stereoselectively synthesized by means of an efficient method starting from L‐aspartic acid (1). Dieckmann reaction of 4‐benzyl 1‐t‐butyl N‐t‐butyl‐oxycarbonyl‐N‐ethoxycarbonylmethyl‐L‐aspartate (4) provided product 5 which consisted of a mixture of (2S,5S)‐ and (2R,5S)‐1‐t‐butyloxycarbonyl‐3‐oxopyrrolidine‐2, 5‐dicarboxylates in a ratio of 95:5. Treating 1‐t‐butyl 6‐ethyl 2‐L‐(t‐butyloxycarbonyl)anuno‐5‐diazo‐4‐oxoadipate (8), prepared from 1, with rhodium(II) acetate dimer also afforded a good yield of 5. The Wittig reaction of 5, followed by catalytic hydrogenation and then deprotection provided compound I.
Derivation of fluorine‐containing pyridine dicarboxylates. II. Elaboration at the 4‐position
Authors: Chupp John P. , Molyneaux John M.
Published: March 2009

In response to the bio‐activity found in fluorine‐containing 4‐alkyl‐3, 5‐pyridinedicarboxylates, a series of novel 4‐substituted derivatives, not directly available by Hantzsch sequences, were prepared. Starting 4‐alkylpyridines, 1, were converted via enamine 2 to materials 3–8. Derivatives 9–16 in turn were derived from aldehyde 3, while acid derivatives 28–36 were prepared from 14. Addition of oxygen, sulfur, and carbenoids effected conversion of 4‐allylpyridine 16 to epoxy and cyclopropyl derivative 16–22. A number of neighboring group effects were noted, including those forming the fused‐ring systems 23‐27.
The synthesis of a new 8‐azaprostanoid
Authors: Biaggio Francisco C. , Barreiro Eliezer J.
Published: March 2009

The synthesis of a new 8‐azaprostanoid is described, using 2‐carboethoxycyclopentanone as starting material.
Synthesis of 4H‐benzo[a]phenoselenazin‐4‐ones as near‐ir dyes
Authors: Ishida Tetsuya , Sakakibara Makoto , Ueno Yoshio , Hasegawa Kan‐Ichi
Published: March 2009

The condensation of 2‐bromo‐ or 2, 6‐dibromo‐4, 8‐bis(alkylamino)‐1, 5‐naphthoquinones with zinc 2‐amino‐benzeneselenolates gave 1, 5‐bis(alkylamino)‐4H‐benzo[a]phenoselenazin‐4‐one and the 3‐ and/or 10‐substituted compounds. These phenoselenazone derivatives absorb nearly infrared light and can be used as optical recording media for a laser beam.
Studies of benzylisoquinolines. Comparison of the reactivity of the methylene group in 1‐benzyl and 4‐benzylisoquinolines
Authors: Vaccher Claude , Berthelot Pascal , Devergnies Monique , Debaert Michel , Bonte Jean‐Paul , Viel Claude
Published: March 2009

While examining the oxidation of 4‐benzylisoquinolines to the corresponding 4‐benzoylisoquinolines as well as the reactivity of these ketones towards hydroxylamine, reduction reagents and Grignard's reagents, there was found a definite difference in the behavior of the methylene group for these compounds as compared to that of papaverine (1‐benzylisoquinolines).
A simple synthesis of dimethyl 2‐pyridone‐4, 5‐dicarboxylate derivatives
Authors: Kawahara Norio , Shimamori Takako , Itoh Tsuneo , Takayanagi Hiroaki , Ogura Haruo
Published: March 2009

1‐Hydroxyphenyl‐2‐pyridone derivatives 8, 10 and 11 were easily prepared by treatment of methyl isocro‐tonate derivatives 6 with base at room temperature in good yields.
Preparation of benzofuroxans and benzofurazans of 2,3,4,5‐tetrahydrobenzo[b] [1,4]dioxocin and related compounds
Authors: Takakis Ioannis M. , Hadjimihalakis Phaedon M.
Published: March 2009

The novel benzofuroxans 1d, 2 and benzofurazans 3,4 have been prepared in good yields. Nitration of 5c furnished the mononitro‐derivatives 6a and 6b in the unusually high relative ratio 6a:6b of 23:77. Direct nitration of 5c or 6a + 6b afforded the unexpected dinitro‐derivative 8b as the major product along with the isomeric 8a, 8c and 8d. Improvement in the yield of 5c (to 86%) is reported.
Synthesis of new imidazole derivatives as potential inhibitors of thromboxane synthetase
Authors: Banfi Aldo , Sala Alberto , Soresinetti P. Angelo , Russo Giovanni
Published: March 2009

The preparation of new imidazole derivatives containing a carboxylic moiety such as succinic, adipic or benzoic into the side chain, is reported starting from the suitable imidazole intermediates.
Nitrogen bridgehead compounds. Part 77. Addition reaction of 9‐methylene‐6,7,8,9‐tetrahydro‐4H‐pyrido[1,2‐a]pyrimidin‐4‐ones
Authors: Tóth Gábor , Janke Frank , Hermecz István , Bitter István
Published: March 2009

Addition of bromine or thioacetic acid onto 6‐methyl‐9‐methylenetetrahydro‐4H‐pyrido[1,2‐a]pyrimidin‐4‐ones is stereoselective and gives the cis 6‐Me,9‐CH substituted products. Addition is also stereoselective in respect to the C(9) and C(10) centers, and gives as the primary product the erythro diastereomer, which may then undergo epimerization to the threo isomer. Relative configuration and predominant conformation of the products were determined by 1D and 2D nmr methods.
Synthesis of (‐)‐(S)‐3‐sec‐butyl‐ and (+)‐(S)‐5‐sec‐butyl‐2(1H)‐pyridinone
Authors: Chelucci Giorgio , Giacomelli Giampaolo
Published: March 2009

Optically active (+)‐(S)‐5‐sec‐butyl‐ and (‐)‐(S)‐3‐sec‐butyl‐2(1H)‐pyridinone are synthesized and the relationship between optical activity and minimum optical purity of the latter is determined.
Mass spectrometric synthesis. V. The gas‐phase ion‐molecule dimerization of some sulfur containing heterocycles
Authors: Audisio Guido , Catellani Marinella , Destri Silvia , Pelli Beatrice , Traldi Pietro
Published: March 2009

The gas‐phase, ion‐molecule reactions occurring in the ion source of a mass spectrometer between differently substituted thiazoles, employed as starting compounds for synthesis of polymers exhibiting semiconducting properties, have been studied in detail. The structural characterization of the dimeric moieties so obtained has been carried out by exact mass measurements, linked scans for metastable analysis and collisional spectroscopy.
Studies on pyrazines. 19 . A novel formation of alkenynylpyrazines in palladium‐catalyzed reaction of 2‐chloropyrazine and its N‐oxide with acetylenes
Authors: Sato Nobuhiro , Hayakawa Akemi , Takeuchi Ryo
Published: March 2009

Reaction of 3‐chloropyrazine 1‐oxide (1) with 1‐hexyne (2a) in the presence of tetrakis(triphenylphosphine)‐palladium(O) and potassium acetate in DMF afforded 3‐(1‐hexynyl)pyrazine 1‐oxide (3a) and 3‐(2‐butyl‐1‐octen‐3‐ynyl)pyrazine 1‐oxide (4a). The novel formation of 4a was elucidated to result from codimerization of 3a with 2a. The details of reaction are discussed on the basis of findings in palladium(O)‐catalyzed reaction of other chloroheterocycles.
The synthesis and biological activity of 8‐fluoro‐9‐(4‐methyl‐1‐piperazinyl)‐6‐oxo‐6H‐benzo[c]quinolizine‐5‐carboxylic acid
Authors: Ziegler Carl B. , Moran Daniel B. , Fenton Thomas J. , Lin Yang‐I.
Published: March 2009

A one‐pot synthesis of ethyl 8,9‐difluoro‐6‐oxo‐6H‐benzo[c]quinolizine‐5‐carboxylate 11 has been developed. The condensation of ethyl 2‐pyridylacetate and 2,4,5‐trifluorobenzoyl chloride followed by intramolecular nucleophilic aromatic substitution gave the desired ring system. This intermediate was converted to the title compound and its in vitro biological activity is reported.
Synthesis of linear polyquaternary salts derived from 4,4′‐Bipyridine
Authors: Summers Lindsay A. , Andriopoulos Nicolaos , Channon Anne‐Louise
Published: March 2009

1,1″‐(1,3‐Propanediyl)bis‐4,4′‐bipyridinium dibromide is converted to 1,1″‐(1,3‐propanediyl)bis[1′‐(3‐hydroxypropyl)‐4,4′‐bipyridinium] tetrabromide by reaction with 1,3‐dibromopropane in hot aqueous dimethylformamide. The tetraquaternary salt participates in a dequaternization and coupling reaction on treatment with hot aqueous hydrobromic acid to afford an octaquaternary salt, which is readily converted to decaquaternary and dodecaquaternary derivatives. The 1,4‐butanediyl analogue participates in a similar sequence of reactions.
Novel syntheses of dihydroxanthyletin and dihydroseselin derivatives
Authors: Jetter Michele M. , Heindel Ned D. , Laskin Jeffrey D.
Published: March 2009

In a one‐step alkylation, ring‐closure 7‐hydroxycoumarins are condensed in acid media with allyl and homoallyl halides or alcohols to linear 6,7‐dihydro‐2H,8H‐benzo[1,2–6:5,4‐b']dipyran‐2‐ones. If both carbon‐6 and carbon‐8 are unsubstituted in the original coumarin, cyclization to angular isomers 9,10‐dihydro‐2H,8H‐benzo[1,2–6:3,4‐b']dipyran‐2‐ones competes. These compounds are higher ring homologs of psoralens and angelicins commonly employed in phototherapy of skin disorders.
The synthesis of novel polycyclic heterocyclic ring systems via photocyclization. 2 . Benzo[h][1]benzothieno[2,3‐c]quinoline and benzo[h][1]benzothieno[2,3‐c]quinoline
Authors: Luo Jiann‐Kuan , Castle Raymond N.
Published: March 2009

The synthesis of two previously unknown unsubstituted heterocyclic ring systems namely, benzo[h][1]benzothieno[2,3‐c]quinoline (6) and benzo[f][1]benzothieno[2,3‐c]quinoline (12) is reported. These two novel ring systems have been assembled by photocyclization of the appropriate amides.
Synthesis and reaction of methylbenzo[a]quinolizinium salts
Authors: Arai Sadao , Yamazaki Masuo , Hida Mitsuhiko
Published: March 2009

All isomers of (monomethyl)benzo[a]quinolizinium salts including five new monomethyl derivatives were prepared by photocyclization, sulfur extrusion, or cyclodehydration reaction, and their aldol‐type condensation was examined. The 2‐ and 4‐methyl derivatives 3b and 3c reacted with p‐methoxybenzaldehyde in the presence of piperidine to yield trans‐(p‐methoxystyryl)benzo[a]quinolizinium salts 11. The other methyl derivatives did not react with the aldehyde. The methyl group was reactive at the 2‐ and 4‐positions, located para and ortho to the azonia ring nitrogen, respectively; however, it was unreactive at the 6‐position located at another ortho position.
Synthesis of 17β‐hydroxy‐1′‐H‐5α‐androst‐2‐eno[3,2‐b]pyrrole and 17β‐hydroxy‐1′‐H‐5α‐androst‐3‐eno[3,4‐b]pyrrole from O‐(2‐hydroxyethyl)ketoxime precursors
Authors: Ellames George J. , Johnston David , Smith David I.
Published: March 2009

Pyrrolosteroids such as 17β‐hydroxy‐1′‐H‐5α‐androst‐2‐eno[3,2‐b]pyrrole (1) and the novel 17β‐hydroxy‐1′‐H‐5α‐androst‐3‐eno[3,4‐b]pyrrole (12) can be synthesized from the corresponding O‐(2‐hydroxyethyl)ketoxime precursors. In the case of 1, yields compare favourably with previously reported literature methods.
Pteridines bearing acetylene‐containing sidechains at c‐2:Preparation and attempted cycloaddition reactions
Authors: Haider Norbert , Van Der Plas Henk C.
Published: March 2009

The preparation of a series of pteridine derivatives 1a‐d bearing S‐, O‐, or C‐linked ω‐alkynyl side chains at C‐2 is described. Furthermore, an improved synthesis of 2‐chloropteridine is proposed. Compounds 1a‐d were found not to undergo intramolecular cycloaddition reactions under thermolytic conditions.
Synthesis of 1,2,4‐triazolo[4′,3′:1,6]pyridazino[4,5‐b]quinoline derivatives
Authors: Vomero S. , Anzini M. , Cappelli A.
Published: March 2009

This paper reports the synthesis of 10‐phenyl‐2H‐pyridazino[4,5‐b]quinoline‐1‐thione 10 and its further transformation into the hitherto unknown 12‐phenyl‐1,2,4‐triazolo[4′,3′:1,6]pyridazino[4,5‐b]quinoline 4. 3‐Carbethoxy‐2‐dichloromethyl‐4‐phenylquinoline 8 was reacted with hydrazine to give 9 which in turn was transformed by the Lawesson Reagent into the corresponding thione 10. On treating 10 with anhydrous hydrazine, 11 was obtained and subsequently cyclized in the presence of formic or acetic acids to afford the tetracyclic derivatives 4a and 4b, respectively, in satisfactory yields. When 3‐carbethoxy‐2‐chloromethyl‐4‐phenylquinoline 5 was reacted with hydrazine, compound 7 was the sole isolated product.
An alternate synthesis, x‐ray crystal structure and p388 activity of 1,2‐bis(dibenzophospholyl‐1)ethane
Authors: Sutton Blaine M. , Girard Gerald R. , Eggleston Drake S. , Baures Paul W. , Faucette Leo F. , Johnson Randall K. , Hill David T.
Published: March 2009

Synthesis of 1,2‐bis(dibenzophospholyl‐l)ethane (2) in 45% yield was accomplished in a single step via the coupling of 2,2′‐dilithiobiphenyl with 1,2‐bis(dichlorophosphino)ethane. The dilithio reagent was generated in situ by the metalation of 2,2′‐dibromobiphenyl with n‐butyl lithium. The 31P[1H] nmr chemical shift of 2 at δ 11.2 ppm (deuteriochloroform) is slightly upfield from the δ 12.8 ppm observed for 1,2‐bis(diphenylphosphino)ethane, the nonconstrained analog 1, relative to external trimethyl phosphate (δ 31P 2.0 ppm). X‐ray crystallography showed 2 crystallized in space group P21/c with lattice constants a = 5.752(1) Å, b = 12.891(2) Å, c = 13.675(3) Å and β = 100.74(2)° with Z = 2. Compound 2 formed a bis[chlorogold(I)] complex in a fashion similar to the known metal complexing ligand 1. Evaluation of 2 in an ip P388 leukemia mouse model resulted in an increased life span (ILS) of 70% relative to controls, at a maximally tolerated dose (MTD) of 20.2 μmol/kg. By comparison 1 afforded an ILS of 100% at an MTD of 40 μmol/kg.
Methyltriazolocoumarins: New furocoumarin isosters as potential photochemotherapeutic agents
Authors: Rodighiero P. , Chilin A. , Pastorini G. , Guiotto A. , Manzini P.
Published: March 2009

A number of new methyltriazolocoumarins with a linear psoralen‐like structure or an angular angelicin‐like structure were synthetized. The syntheses were performed starting from the appropriate methylated 7‐aminocoumarins which were nitrated, reduced and successively diazotized with concomitant cyclization to form the condensed triazolo ring. The new methyltriazolocoumarins show promising spectroscopic properties which are potentially predictive of their photochemical and photobiological behaviour.
An efficient synthesis of the novel triazoloquinazoline adenosine antagonist, CGS 15943
Authors: Gelotte Karl O. , Mason David N. , Meckler Harold , Shieh Wen‐Chung , Starkey Colleen M.
Published: March 2009

An efficient synthesis of the novel triazoloquinazoline adenosine antagonist, CGS 15943, is reported in five steps in approximately 50% overall yield. A key reaction in the synthetic sequence is the double cyclization of an N‐(substituted‐2‐cyanophenyl)carbamate with a carboxylic acid hydrazide to afford a [1,2,4]triazolo‐[1,5‐c]quinazolin‐5(6H)‐one in high yield without either a Dimroth or “translocative” rearrangement occurring. Another key reaction is the condensation of a 2‐(1H‐1,2,4‐triazol‐5‐yl)benzenamine with cyanamide under acidic conditions to prepare a guanidine.
Reactions of triacetylmethane with monosubstituted hydrazines and amidine analogues. Syntheses of 4‐acetyl‐3,5‐dimethylpyrazole amidinohydrazone and 1,3,5‐triazine derivatives
Authors: Takagi Kaname , Bajnati Abdelilah , Hubert‐Habart Michel
Published: March 2009

Triacetylmethane (1) reacts with amidinohydrazines in acidic medium to afford 4‐acetyl‐3,5‐dimethylpyrazole amidinohydrazone derivatives 2,4. However, a similar reaction of 1 with thiosemicarbazide or semicarbazide led mainly to 3,5‐dimethylpyrazole (6). The great propensity of 1 to hydrolysis accounts for this last transformation, as well as for the fact that with guanidine it led to 2‐amino‐4,6‐dimethylpyrimidine (10) and with S‐methylisothiourea it provided the unexpected 2‐amino‐4‐methyl‐6‐methylthio‐1,3,5‐triazine (11).
Potassium fluoride‐promoted reaction of (2‐chloro‐2‐nitroethenyl)benzenes with 1,3‐dicarbonyl compounds. A general synthesis of 6,6‐dimethyl‐2‐nitro‐3‐phenyl‐3,5,6,7‐tetrahydro‐4(2H)benzofuranones and some analogs
Authors: Dauzonne Daniel , Demerseman Pierre
Published: March 2009

A convenient procedure to prepare in good yields 6,6‐dimethyl‐2‐nitro‐3‐phenyl‐3,5,6,7‐tetrahydro‐4(2H)‐benzofuranones starting from (2‐chloro‐2‐nitroethenyl)benzenes and 5,5‐dimethyl‐1,3‐cyclohexanedione in the presence of potassium fluoride is reported. This method also proved efficient with other 1,3‐dicarbonyl compounds, and has been successfully extended to 1,3‐cyclohexanedione, 2,5‐pentanedione, dibenzoylmethane and ethyl acetoacetate.
Cycloaddition‐elimination reactions of 5‐imino‐1,2,4‐dithiazolidin‐3‐ones with heterocumulenes
Authors: L'Abbé Gerrit , Vandendriessche Anna
Published: March 2009

5‐Benzylimino‐1,2,4‐dithiazolidin‐3‐one (2a) reacts with heterocumulenes (isocyanates, isothiocyanates, ketenes) with elimination of carbonyl sulfide, yielding the heterocycles 6–8. The thiadiazolidine 6a, obtained from 2a and phenyl isocyanate, underwent similar reactions but under milder conditions, indicating that phenyl isocyanate is a better leaving group than carbonyl sulfide.
A new and unexpected aminoisoquinoline formed under bischler‐napieralski reaction conditions provides for A new synthesis of 3‐aminoisoquinolines
Authors: Markovich Kimberly M. , Hamada Akihiko , Miller Duane D.
Published: March 2009

Treatment of an amide, 1, of a substituted 2‐phenethylamine using Bischler‐Napieralski reaction conditions with acetonitrile as a solvent, gave the desired dihydroisoquinoline 2 as well as an unexpected 3‐aminoisoquinoline product 3. The applicability of this finding as a method of synthesizing 3‐aminoisoquinoline derivatives was examined.
Chemistry of thienopyridines. XXXVIII. Diels‐Alder reactions of thienopyridine sulfones. Part 2
Authors: Klemm L. H. , Sur Sandip K. , Louris John N. , Tran Long K. , Yee Sidney , Hamilton Steven R.
Published: March 2009

Thieno[3,2‐b]pyridine 1,1‐dioxide (2) undergoes Diels‐Alder condensation with the dienophiles cyclopentadiene, anthracene, and naphthacene in a manner analogous to its isomer thieno[2,3‐b]pyridine 1,1‐dioxide (1). Compound 2 dimerizes in refluxing xylene with the loss of sulfur dioxide plus either the loss or transfer of hydrogen to give a small yield (ca. 2%) of pyrido[2′,3′:4,5]thieno[3,2‐f]quinoline 7,7‐dioxide (7) and its 5,6‐dihydro derivative 12. Formation of 7 and 12 are compared and contrasted with products reported from dimerization of 1 and of benzo[b]thiophene 1,1‐dioxide and its derivatives.
On the methylation of 5‐(4‐alkoxyphenyl)‐15‐(4‐pyridyl)porphyrins
Authors: Roeterdink F. , van der Plas H. C.
Published: March 2009

Mixed condensation of 3,3′‐diethyl‐4,4′‐dimethyl‐2,2′‐dipyrrolylmethane 1 with 4‐formylpyridine 2 and 4‐alkoxybenzaldehyde 3 in acid medium and subsequent oxidation of the reaction mixture with DDQ gives, among other compounds, title compound 5. An efficient methylation procedure of the pyridyl group in 5‐(4‐alkyoxyphenyl)‐15‐(4‐pyridyl)porphyrins is described. Mixed condensation of 1 with N‐methyl‐4‐formylpyridinium salt 9 and 3 yields among other compounds 5‐(4‐N‐methylpyridiniumiodide)porphyrin 10.
Thiophene systems. 11. The synthesis of novel thieno[4,3,2‐de] tricyclic ring systems
Authors: Russell Ronald K. , Rampulla Richard A. , van Nievelt Caroline E. , Klaubert Dieter H.
Published: March 2009

The synthesis of thieno[4,3,2‐de] tricyclic compounds is described. The N‐1 alkylation of I produced the alkanoic ester precursors. After hydrolysis, the corresponding carboxylic acids were cyclized to the title compounds II. This cyclization step was accomplished with 1:10 phosphorus pentoxide‐methanesulfonic acid. The ketones II were further modified to introduce additional functionality onto this novel tricyclic ring system.
A convenient large scale synthesis of 2,6‐dimethyl‐4‐(trimethylstannyl)pyridine
Authors: Singh Baldev , Lesher George Y. , Pennock Patrick O.
Published: March 2009

Reaction of phosphorus oxychloride with 2,6‐dimethylpyridine N‐oxide hydrochloride (1) gave a mixture of 2‐(chloromethyl)‐6‐methylpyridine (2) and 4‐chloro‐2,6‐dimethylpyridine (3). Treatment of this mixture with triethylamine converted 2 to the quaternary salt 4 which was separated by water extraction leaving 3 which was subsequently reacted with trimethylstannyl sodium to yield 2,6‐dimethyl‐4‐(trimethylstannyl)pyridine (6).
Isolation of keto‐s‐phenylthioxime of [23]cyclophane‐1,2‐dione. Re‐visited contraction of 1,2,5‐thiadiazole ring incorporated in a [23]cyclophane bridge by phenylmagnesium bromide
Authors: Hatta Taizo , Mataka Shuntaro , Tashiro Masashi , Numano Katsutoshi , Tanimoto Satoshi , Tori‐I Akiyoshi
Published: March 2009

[23]Paracyclophane derivative 3 of keto‐S‐phenylthioxime which is the hydrolyzed product of the hypothetical intermediate in the reaction of 1,2,5‐thiadiazole with organometallic reagents, was obtained, together with diketone 1, in the reaction of 1,2,5‐thiadiazolo[23]paracyclophane 2 with two equivalents of phenylmagnesium bromide. Contrary, [23]metacyclophane 7 gave only diketone 12 in the reaction with phenylmagnesium bromide under the same conditions.
The synthesis and transformations of 2H‐naphtho‐[1,2‐b]pyran‐2‐one derivatives. Naphtho[2′,1′:5,6]‐pyrano[3,4‐d][1,3]oxazines and naphtho[1′,2′:5,6]pyrano[3,4‐d]‐pyrimidines, derivatives of two new heterocyclic systems
Authors: Fajgelj Simona , Stanovnik Branko , Tišler Miha
Published: March 2009

1,4‐Naphthoquinone (1) was transformed with alkyl 2‐aminofumarates 2 into 2H‐naphtho[1,2‐b]pyran‐2‐ones 3 and 4, which served as intermediates in the synthesis of 7, 8 and 13, which are derivatives of two new heterocyclic systems: naphtho[2′,1′:5,6]pyrano[3,4‐d][1,3]oxazine and naphtho[1′,2′:5,6]pyrano[3,4‐d]pyrimidine.
Hydroxylation of 5H‐3‐Oxo‐2,3,6,7,8,9‐hexahydroimidazo[1,2‐a]azepine derivatives by molecular oxygen
Authors: Campagna Francesco , Carotti Angelo , Casini Giovanni
Published: March 2009

O‐Methylcaprolactim 3 reacts in hot dimethylsulfoxide with α‐amino acids 4 to give 5H‐3‐oxo‐2,3,6,7,8,9‐hexahydroimidazo[1,2‐a]azepines 6 and, unexpectedly, hydroxylated derivatives 7a,c and 8c. The structures of the hydroxylated compounds have been elucidated by spectroscopic means and, when necessary, further confirmed by an independent unequivocal synthesis. The formation of 7 as well as the isomerization of 7c to 8c are discussed in detail.
Protected 2‐indoleacetaldehyde derivatives from 2‐acylindoles
Authors: Bonjoch Josep , Linares Ana , Pérez M.‐Lluïsa , Bosch Joan
Published: March 2009

The conversion of tetracyclic 2‐acylindoles 1 to the protected 2‐indoleacetaldehydes 4 and 6 is reported. 2‐Indoleacetaldehydes 5 undergo oxidation to the corresponding 2‐acylindoles 1.
Pyrrolopyridazine nucleosides. The synthesis of certain 1‐β‐D‐ribofuranosyl‐1H‐pyrrolo[2,3‐d]pyridazin‐4(5H)‐ones
Authors: Girgis Nabih S. , Robins Roland K. , Cottam Howard B.
Published: March 2009

Nucleosides of pyrrolo[2,3‐d]pyridazin‐4(5H)‐ones were prepared by the single‐phase sodium salt glycosylation of appropriately functionalized pyrrole precursors. The glycosylation of the sodium salt of ethyl 4,5‐dichloro‐2‐formyl‐1H‐pyrrole‐3‐carboxylate (4), or its azomethino derivative 7, with 1‐bromo‐2,3,5‐tri‐O‐benzoyl‐D‐ribofuranose in acetonitrile afforded the corresponding substituted pyrrole nucleosides ethyl 4,5‐dichloro‐2‐formyl‐1‐(2,3,5‐tri‐O‐benzoyl‐β‐D‐ribofuranosyl)‐1H‐pyrrole‐3‐carboxylate (5) and ethyl 4,5‐dichloro‐2‐phenylazomethino‐1‐(2,3,5‐tri‐O‐benzoyl‐β‐D‐ribofuranosyl)‐1H‐pyrrole‐3‐carboxylate (8), respectively. The latter, upon treatment with hydrazine, afforded the annulated product 2,3‐dichloro‐1‐β‐D‐ribofuranosyl‐1H‐pyrrolo[2,3‐d]pyridazin‐4(5H)‐one (6), in good yield. The unsubstituted analog 1‐β‐D‐ribofuranosyl‐1H‐pyrrolo[2,3‐d]pyridazin‐4(5H)‐one (9), was obtained upon catalytic dehalogenation of 6. This report represents the first example of the synthesis of nucleosides of pyrrolopyridazines.
On the mechanism of thermal decomposition of 4‐alkyl‐5‐sulfonylimino‐Δ2‐1,2,3,4‐thiatriazolines
Authors: L'abbé Gerrit , Bosman Joris
Published: March 2009

The kinetics of the thermal decomposition of several sulfonyl substituted thiatriazolinimines 1a‐g were investigated in different solvents both in the presence and in the absence of trapping reagents. The first‐order rate constants observed in all cases, are dependent on the inductive effect of the sulfonyl substituent (R), as well as on solvent polarity, but independent on the nature and concentration of the co‐reagent. These results, and the low activation energy, are rationalized by assuming an anchimeric assistance of the sulfonyl group during thermolysis. This would give the intermediate 7, which collapses to the thiaziridinimine 2 before being trapped by the co‐reagent.
Synthesis of 8‐amino‐4‐methylthio‐6‐methyl‐2‐(β‐D‐ribofuranosyl)‐2,6‐dihydro‐1,2,3,5,6,7‐hexaazaacenaphthylene and an unusual reductive ring‐opening of the 1,2,3,5,6,7‐hexaazaacenaphthylene ring system
Authors: Kawasaki Andrew M. , Townsend Leroy B.
Published: March 2009

The tricyclic nucleoside 8‐amino‐4‐methylthio‐6‐methyl‐2‐(β‐D‐ribofuranosyl)‐1,2,3,5,6,7‐hexaazaacenaphthylene (3) was synthesized from 3‐cyano‐4,6‐bis(methylthio)‐1‐(β‐D‐ribofuranosyl)pyrazolo[3,4‐d]pyrimidine (1). Attempts to synthesize 8‐amino‐6‐methyl‐2‐(β‐D‐ribofuranosyl)‐1H‐2,6‐dihydro‐1,2,3,5,6,7‐hexaazaacenaphthylene (5) ([an aza analog of 6‐amino‐4‐methyl‐8‐(β‐D‐ribofuranosyl)‐1,3,4,5,8‐pentaazaacenaphthylene (TCN)], which is a potent antitumor agent), by the treatment of 3 with Raney nickel did not afford the desired aza analog of TCN. Instead, it was established that a reductive cleavage of the pyridazine moiety of 3 had occurred to give 4‐methylamino‐6‐methylthio‐1‐(β‐D‐ribofuranosyl)‐1H‐pyrazolo[3,4‐d]pyrimidine‐3‐carboxamidine (6). Assuming that solubility was a problem in the reductive step, the isopropylidene derivative of 3, 8‐amino‐6‐methyl‐4‐methylthio‐2‐(2,3‐O‐isopropylidene‐β‐D‐ribofuranosyl)‐2,6‐dihydro‐1,2,3,5,6,7‐hexaazaacenaphthylene (8), was treated with Raney nickel, only to observe that a similar reductive ring cleavage of 8 had occurred to afford 4‐methylamino‐6‐methylthio‐1‐(2,3‐O‐isopropylidene‐β‐D‐ribofuranosyl)‐1H‐pyrazolo[3,4‐d]pyrimidine‐3‐carboxamidine (10) and 4‐methylamino‐1‐(2,3‐O‐isopropylidene‐β‐D‐ribofuranosyl)‐1H‐pyrazolo[3,4‐d]pyrimidine‐3‐carboxamidine (11). Structural assignments for all products were established by physico‐chemical procedures.
A study on m‐chloroperbenzoic acid and lead tetraacetate oxidation of some 1‐aroyl‐4,5‐dihydro‐4,4‐dimethyl‐5‐methylene‐1H‐pyrazoles
Authors: Mitkidou Sophia , Stephanidou‐Stephanatou Julia
Published: March 2009

1‐Aroyl‐4,5‐dihydro‐5‐methylene‐1H‐pyrazoles 1 are converted upon oxidation with m‐chloroperbenzoic acid to the pyrazolones 2. The same aroyl enamides 1 are also oxidized with LTA to form the acetoxy derivatives 7 and 8. The reaction mechanisms are discussed.
Chemistry of thienopyridines. XXXIX. Synthesis of benzothieno[2,3‐h]isoquinoline and related studies
Authors: Klemm L. H. , Severns Bryon , Wynberg Hans
Published: March 2009

Benzo[b]thiophene‐2‐carboxaldehyde undergoes condensation with 4‐methylpyridine and with 2‐methylquinoline to produce trans‐diarylethenes (52% and 76%, respectively). The former alkene photocyclizes in cyclohexane to yield [1]benzo[2,3‐h]isoquinoline (35%), while the latter alkene does not give successful, analogous cyclization.
Some fatty acids having an O‐heterocycle in their terminal positions. II. ω‐(3‐Coumarinyl)alkanoic acids and ω‐(2‐chromonyl)alkanoic acids
Authors: Yamaguchi Seiji , Saitoh Miyuki , Kawase Yoshiyuki
Published: March 2009

Some ω‐3‐coumarinyl)alkanoic acids 1a, n = 3‐6 were synthesized by cyclization of corresponding ethyl o‐formylphenyl alkanedioate 3 with DBU followed by hydrolysis. By a similar cyclization, some ω‐(2‐chromonyl)alkanoic acids 2a, n = 3‐6 were also obtained from the cyclization of corresponding o‐acetylphenyl ethyl alkanedioate 4.
Nouveaux hétérocycles à partir d'esters cyaniques. Arylimino‐2 et arylamino‐2 4H‐benzoxazin‐1,3 ones‐4, leur tautomérie et étude de leur alkylation régiosélective
Authors: Hedayatullah Mir , Lion Claude , Pailler Jacques
Published: March 2009

Une nouvelle série de benzoxazinones substituées en position 2 a été obtenue par action d'amines aromatiques primaires sur les cyanates d'aryle renfermant en position ortho un groupe éthoxycarbonyle. L'étude de leurs spectres ir et de rmn a montré que leur forme tautomère prépondérante correspond à une structure d'arylimino‐2 4H‐benzoxazin‐1,3 one‐4. La synthèse régiosélective de leurs dérivés alkylés sur les azotes cyclique et extracyclique, par alkylation en milieu d'éthanol, de diméthylformamide et en catalyse par transfert de phase solide‐liquide a été réalisée.
Synthesis and 1H NMR characterization of substituted 1‐amino‐9‐imino‐4‐nitro‐9,10‐dihydr oacridines as potential antitumor agents
Authors: Cholody Wieslaw M. , Konopa Jerzy , Antonini Ippolito , Martelli Sante
Published: March 2009

A convenient method for the synthesis of unsubstituted and substituted 1‐amino‐9‐imino‐4‐nitro‐9,10‐dihydroacridines, 9 and 10, respectively, is reported. Their 1H nmr data are reported and discussed in order to confirm the imino tautomeric structure.
Polycyclic N‐hetero compounds. XXXIV. Syntheses and evaluation of antidepressive activity of benzofuro‐[2,3‐e]imidazo[1,2‐c]pyrimidines and their precursors
Authors: Hirota Takashi , Sasaki Kenji , Tashima Yohsuke , Nakayama Taiji
Published: March 2009

Syntheses of 2,3‐dihydrobenzofuro[2,3‐e]imidazo[1,2‐c]pyrimidine and its 5‐substituted derivatives, corresponding to B‐nor‐6‐oxa‐11,13,15‐triazasteroids, are described. These products and their precursors were screened to evaluate the antidepressive activity.
Acid‐catalysed rearrangement of 1‐oximinoacridine‐1,9‐diones. synthesis of novel 4,5‐dihydro‐3H‐isoxazolo[3,4,5‐kl]acridines
Authors: Venugopalan B. , Bapat C. P. , De Souza E. P. , De Souza N. J.
Published: March 2009

A polyphosphoric acid (PPA) catalysed internal cyclization of 1‐oximinoacridine‐1,9‐diones 2 to novel isoxazolo[3,4,5‐kl]acridines 3 is reported. Some of the compounds displayed antimalarial activity in animal models.
Synthesis of α‐(aminomethylene)‐9H‐purine‐6‐acetic acid derivatives
Authors: Hamamichi Norimitsu , Miyasaka Tadashi
Published: March 2009

α‐(Aminornethylene)‐9H‐purine‐6‐acetamide (3a) and the corresponding ethyl acetate 9 have been synthesized by catalytic hydrogenation of 6‐cyanomethylenepurine derivatives 2 and 7 which were obtained by the substitution of 6‐chloropurine derivatives with α‐cyanoacetamide and ethyl cyanoacetate, respectively. Substitution of α‐(aminomethylene)‐9‐(tetrahydrofuran)‐9H‐purine‐6‐acetamide (3b) with amines gave the corresponding N‐alkyl‐ and N‐arylamines 5, which were treated with acid to give N‐substituted α‐(aminomethylene)‐9H‐purine‐6‐acetamides 6. Substitution of 9 with amines gave the corresponding N‐alkyl‐ and N‐aryl substituted amines 10.
1,3‐Dipolar cycloaddition reactions of nitrile oxides and nitrile imines with 2‐methoxyvinyl phenyl ketone
Authors: Coutouli‐Argyropoulou E. , Thessalonikeos E.
Published: March 2009

Nitrile oxides react regioselectively with 2‐methoxyvinyl phenyl ketone 1 to give 4‐benzoylisoxazoles 4 via elimination of methanol from the primary cycloadducts 3. After heating with an excess of nitrile oxide bis‐cycloadducts 5 were also formed. Reactions of nitrile imines with 1 are less regioselective yielding both 4‐benzoylpyrazoles 9 and 5‐benzoytpyrazoles 10, whereas no bis‐cycloadducts were isolated.
Ring transformation of 4‐amino‐1H‐1,5‐benzodiazepine‐3‐carbonitrile and ethyl 4‐amino‐1H‐1,5‐benzodiazepine‐3‐carboxylate into benzimidazole derivatives with amines
Authors: Aotsuka Tomoji , Okamoto Yoshihisa , Takagi Kaname , Hubert‐Habart Michel
Published: March 2009

The ring contraction of 4‐ammo‐1H‐1,5‐benzodiazepine‐3‐carbonitrile hydrochloride 1 and ethyl 4‐amino‐1H‐1,5‐benzodiazepine‐3‐carboxylate hydrochloride 2 with aromatic primary amines into benzimidazole derivatives 3 and 4 was readily accomplished by heating in methanol. Benzodiazepine 1 also reacted with methylamine and ethylamine at about 40° to give ring‐opened amine adducts 7 which were recyclized to 1 with hydrochloric acid.
Condensed heterocyclic lactams. I. Study on the cyclization methods resulting in 4‐aryl‐3,4‐dihydroquinolin‐2(1H)‐ones
Authors: Hazai László , Deák Gyula , Sohár Pál , Tóth Gábor , Tamás József
Published: March 2009

Cyclization reactions with polyphosphoric acid of 3‐aryl‐3‐hydroxypropionanilides carrying a p‐nitro‐ 7a or p‐amino substituent 10 on the C‐3 phenyl group were investigated. In the case of p‐nitro substitution the preferred reaction is, instead of cyclization, the elimination of water to give the corresponding cinnamic acid derivative. On the other hand, reaction of the p‐amino‐substituted analogue gave the new compound 4‐(4‐aminophenyl)‐3,4‐dihydroquinolin‐2(1H)‐one (2b) in a good yield. The intermediate product of the cyclization was isolated and its structure established.
Stepwise approach to the 2,3‐dihydroimidazo[1,2‐a]pyridine and 5‐oxo‐1,2,3,5‐tetrahydroimidazo[1,2‐a]pyridine ring systems
Authors: Podhorez David E.
Published: March 2009

The syntheses of 2,3‐dihydro‐8‐fluoro‐6‐trifluoromethylimidazo[1,2‐a]pyridine‐3‐carbonitrile (2), 8‐fluoro‐6‐trifluoromethylimidazo[1,2‐a]pyridine‐3‐carbonitrile (9) and 5‐oxo‐8‐trifluoromethyl‐1,2,3,5‐tetrahydroimidazo[1,2‐a]pyridine‐3‐carbonitrile (3) are described. These compounds are constructed in a stepwise approach starting from the properly substituted 2‐halopyridines.
Studies on polycyclic thiaarenes: Part II. An improved synthesis of phenanthro[1,2‐b]thiophene and a synthesis of acenaphtho[1,2‐b]naphtho‐[2,3‐d]thiophene, a novel polynuclear thiaarene
Authors: Kar Gandhi K. , Karmakar Arun C. , Ray Jayanta K.
Published: March 2009

An improved synthesis of phenanthro[1,2‐b]thiophene (6) from 1‐chloro‐3,4‐dihydrophenanthrene‐2‐aldehyde (2) by condensation with thioglycolate followed by hydrolysis, decarboxylation and dehydrogenation is described. A new polycyclic thiophene derivative 14 has also been prepared from acenaphthothiophene (7) by Friedel‐Craft's reaction with phthalic anhydride followed by lactonisation of the keto carboxylic acid 9 and then reduction and finally cyclisation of the resultant aldehyde 13.
Deoxydative substitution of pyridine 1‐oxides by thiols. Part XX. Reactions of (2, 3, and 4‐phenyl)‐, 3‐acetamido‐, 3‐bromo‐, 3‐acetoxy‐, 3‐ethoxypyridine 1‐oxides with 1‐adamantanethiol in acetic anhydride
Authors: Prachayasittikul Supaluk , Doss George , Bauer Ludwig
Published: March 2009

Substitutions of 2, 3, and 4‐substituted pyridine 1‐oxides by 1‐adamantanethiol in acetic anhydride takes place at available α‐, to a lesser degree at β‐, and rarely at γ‐ring carbons. It was found that 2‐phenylpyridine 1‐oxide produces a mixture of 5‐ and 6‐(1‐adamantylthio)‐2‐phenylpyridines, and 4‐phenylpyridine 1‐oxide a mixture of 2‐ and 3‐isomeric sulfides. Substitutions of the 1‐oxides of 3‐phenyl‐, 3‐acetamido‐, 3‐acetoxy‐, 3‐bromo‐, and 3‐ethoxypyridine by 1‐adamantanethiol in acetic anhydride led to mixtures consisting predominantly of 2‐ and 6‐sulfide, and to a lesser extent, the 5‐sulfide. When triethylamine is present in otherwise identical reaction mixtures, the ratio of α to β‐sulfides increases. From the reactions of 3‐ and 4‐phenylpyridine 1‐oxides, there were isolated some N‐acetyl hydroxy (or acetoxy) 1‐adamantylthio substituted 1,2,3,4‐and 1,2,3,6‐tetrahydropyridines, whose structures are discussed.
Intramolecular photocyclization of N‐[(2‐haloaryl)methyl]pyridinium and n‐(arylmethyl)‐2‐halopyridinium salts
Authors: Park Y.‐T. , Joo C.‐H. , Choi C.‐D. , Park K.‐S.
Published: March 2009

Various N‐[(2‐haloaryl)methyl]pyridinium, N‐(arylmethyl)‐2‐halopyridinium and N‐(2‐halobenzyl)iso‐quinolinium salts have been synthesized and their intramolecular photocyclization reactions studied. Upon irradiation the aqueous solution of N‐[(2‐haloaryl)methyl]pyridinium, and N‐arylmethyl‐2‐halopyridinium salts 1, 2 were cyclized to give isoindolium salts. In contrast to the pyridinium salts 1, 2, the aqueous solution of N‐(2‐halobenzyl)isoquinolinium salts 3 appear not to undergo photocyclization. N‐Benzyl‐2‐chloropyridinium salts 1c is more reactive than N‐(2‐chlorobenzyl)pyridinium salt 1a in the photocyclization. N‐(2‐Chlorobenzyl)‐2‐chloropyridinium salt 1d is three times more reactive than 1c. A mechanism of π‐complex formation of the halogen moiety of the pyridinium ring with the phenyl ring is suggested for the reactive pyridinium salt. The triplet energy of the isoquinolinium salts 3 is tool low to photocyclize.
6‐Substituted‐9‐(3‐formamidobenzyl)‐9H‐purines. Benzodiazepine receptor binding activity
Authors: Kelley James L. , Mclean Ed W. , Ferris Robert M. , Howard James L.
Published: March 2009

A series of 6‐substituted‐9‐(3‐formamidobenzyl)purines were synthesized and studied for benzodiazepine receptor (BZR) binding activity. Most of the target compounds were prepared by reaction of 6‐chloro‐9‐(3‐formamidobenzyl)‐9H‐purine (17) with the appropriate amine, alcohol or other nucleophilic reagent. Alternatively, the 6‐cyclopropylaminopurine 5 was synthesized via the nitrobenzyl precursor 22, and the 6‐alkyl‐thiopurines 14 and 15 were prepared by alkylation of the appropriate purine with 3‐formamidobenzyl bromide. Purines with a variety of 6‐substituents retained potent BZR binding properties, although certain bulky 6‐substituents led to compounds with diminished activity. None of the compounds exhibited significant activity on a modified Geller‐Seifter Conflict schedule.
Carbazoledioxazines having long alkyl groups. 2. Synthesis of carbazoledioxazines with angular type structure
Authors: Ikeda Masaaki , Kitahara Kiyoshi , Nishi Hisao
Published: March 2009

Carbazoledioxazines with an angular type structure (5,15‐dialkyl‐7,17‐dialkyloxy‐9,19‐dichloro‐5,15‐dihydrodiindolo[2,3‐c:2′,3′‐n]triphenodioxazines) were selectively synthesized by electrochemical oxidative ring closure of precursors (2,5‐bis(9‐alkyl‐2‐alkyloxy‐3‐carbazolylamino)‐3,6‐dichloro‐1,4‐benzoquinones). The structure was confirmed by 1H‐nmr and other instrumental analyses. Their thermal properties and solubilities were investigated and were compared with those of carbazoledioxazines with a linear type structure.
Reaction of enaminones with carbon disulfide: Synthesis of heterocycles using enamino dithiocarboxylates
Authors: Tominaga Yoshinori , Okuda Hiroto , Kohra Shinya , Mazume Hisako
Published: March 2009

Reaction of various types of enaminones, which are prepared by the condensation of 1,3‐dicarbonyl compounds with aromatic amines, with carbon disulfide in the presence of sodium hydroxide as the base in dimethyl sulfoxide to give the corresponding enamino dithiocarboxylates, 1,3‐thiazines and trithiones. Enamino dithiocarboxylates are cyclized under refluxing in diphenyl ether to give the fused quinoline derivatives. The reaction of 6‐arylamino‐1,3‐dimethyluracils with excess carbon disulfide in the presence of sodium hydroxide and subsequent methylation with dimethyl sulfate gave directly the corresponding 1,3‐dimethyl‐5‐methylthiopyrimido[4,5‐b]quinoline‐2,4(1H,3H)‐diones.
Photocyclization reactions. Part 2 Synthesis of dihydrobenzofuranols using photocyclization of ethyl 2‐formylphenoxyacetates and ethyl 2‐acetylphenoxyacetates
Authors: Horaguchi Takaaki , Tsukada Chikara , Hasegawa Eietsu , Shimizu Takahachi , Suzuki Tsuneo , Tanemura Kiyoshi
Published: March 2009

Photocyclization reactions were carried out on ethyl 2‐formylphenoxyacetates 1a‐e and ethyl 2‐acetylphenoxyacetates 2a‐e in acetonitrile. Irradiation of 1a‐e gave dihydrobenzofuranols 3 in 20–46% yields. Similarly, irradiation of 2a‐e afforded dihydrobenzofuranols 6 and their derivatives 7, 8 in 40–86% yields. Substituent effects on photocyclization and reaction pathways are discussed.
The wolff‐kishner reduction of 2‐acetonyl pyrazines and pyridines. A novel rearrangement
Authors: Paine John B.
Published: March 2009

Wolff‐Kishner reduction of 1‐(6‐methylpyrazin‐2‐yl)‐2‐propanone leads to the formation of 2‐isopropyl‐6‐methylpyrazine (2a), in addition to the expected 6‐methyl‐2‐n‐propylpyrazine. The by‐product 2a is suggested to arise via a spirocyclopropylidene aza‐anion, which serves as a conduit between the initial less‐stable secondary 1‐(2‐pyrazinyl)‐2‐propyl carbanion and the more stable primary 2‐(2‐pyrazinyl)‐1‐propyl carbanion. Similar results were observed for the 1‐(3‐methylpyrazin‐2‐yl) and 1‐(6‐methylpyridin‐2‐yl)‐2‐propanones. The extent of by‐product formation diminished in the pyridine ring system. Electrophilic activation of the ring appears essential since the benzene analog phenylacetone gave no detectable cumene under identical reaction conditions.