bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of pyrazolo[1,5‐a]pyridines and pyrazolo[1,5‐c]pyrimidines by reaction of heterocyclic amidrazones with 1,3‐dicarbonyl compounds
Authors: Köckritz Peter , Riemer Beate , Michler Anke , Hassoun Ahmed , Liebscher Jürgen
Published: March 2009

1,3‐Dicarbonyl compounds 2 react with 1‐amino‐2(1H)‐pyridin‐2‐imines or 1‐amino‐2(1H)‐pyrimidin‐2‐imines 1 giving new pyrazolo[1,5‐a]pyridines or pyrazolo[1,5‐c]pyrimidines 5 respectively by addition, oxidation and condensation. Isolation of an intermediate 3 shows that surprisingly the addition of the CH acidic 1,3‐dicarbonyl compound to position 6 of the pyrimidine 1 is the initial step.
Preparation, structure, and reactivity of 1,3,4,6‐tetrakis‐(isopropylthio)thieno[3,4‐c]thiophene‐palladium complex with tetracyanoethylene
Authors: Tsubouchi Akira , Nakamura Naomi , Sugimoto Akira , Inoue Hiroo , Adachi Tomohiro
Published: March 2009

The reaction of 1,3,4,6‐tetrakis(isopropylthio)thieno[3,4‐c]thiophene (1) with the palladium complex Pd2(dba)3CHCl3 (dba = dibenzylideneacetone) and tetracyanoethylene (TCNE) gave a new palladium complex in which two isopropylthio groups of 1 and the double bond of TCNE were trigonally coordinated to palladium. The X‐ray analysis revealed the electron donation from palladium to TCNE, leading to a lengthening of the CC double bond in TCNE and distortion of TCNE from planarity. The radical cation of 1 and the radical anion of TCNE were detected by ESR spectroscopy in methylene dichloride solution of the complex, although the radical content was estimated from the paramagnetic susceptibility to be less than 1%. The reaction of the complex with aniline gave the same product as that in the reaction of the radical cation of 1 with aniline.
NMR spectra and conformational analysis of some 4,5‐dihydro‐s‐triazolo[3,4‐d][1,5]benzothiazepine derivatives
Authors: Ambrogi Valeria , Grandolini Giuliano , Perioli Luana , Kajtàr‐Peredy Maria , Radics Lajos
Published: March 2009

High field 1H and 13C nmr spectra of a series of 1‐substituted‐4,5‐dihydro‐s‐triazolo[3,4‐d][1,5]benzothiazepine derivatives have been recorded. These have shown that, unless X = H or O, the molecules occur as a mixture of two slowly interconverting conformers at ambient temperatures. Variable temperature nmr experiments disclosed that the energy barrier to interconversion varies with the size of the substituent X located at position 1 of the fused s‐triazole ring.
Synthesis of 9‐(trifluoromethyl)pyrido[1′,2′:1,2]‐imidazo[4,5‐b]quinoxalines
Authors: Iwata Satoru , Sakajyo Mitsumasa , Tanaka Kiyoshi
Published: March 2009

9‐(Trifluoromethyl)pyrido[1′,2′:1,2]imidazo[4,5‐b]quinoxalines (9‐CF3‐PIQs) were obtained from the cyclization of 2‐amino‐3‐chloro‐6‐(trifluoromethyl)quinoxaline (1a) with some substituted pyridines. 3‐[2‐(4‐Pyridyl)ethenyl]‐9‐CF3‐PIQ, one of thus obtained 9‐CF3‐PIQs, cyclized with another molecule of 1a to produce the dihydro bis‐PIQ‐ethene derivative.
Conversion of 1‐benzyl‐4‐aminotetrahydropyridine‐3‐carboxylic acid methyl ester to antithrombotic pyrido[4,3‐d]pyrimidine‐2,4‐diones and to (2‐oxotetrahydropyrimidin‐4‐ylidene)acetic acid methyl esters
Authors: Furrer H. , Wagner R. , Fehlhaber H.‐W.
Published: March 2009

6‐Benzyl‐3‐methyl‐5,6,7,8‐tetrahydro‐1H‐pyrido[4,3‐d]pyrimidine‐2,4‐dione 2, a representative of new antithrombotic compounds with favourable cerebral and peripheral effects has been synthesized from enamine 1 in good yield by two methods. The thermal fusion of 1 with ureas gave the pyrido[4,3‐d]‐pyrimidine‐2,4‐diones 5a, 2 and 5b and unexpectedly the esters 6 and 7. The structure of 6 was deduced from its spectroscopic properties and was proven by ozonolysis to cleavage products 9 and 10 and by oxidative hydrolysis to pyrimidin‐2‐one 13. The (Z)‐configured 6 was converted to (E)‐configured 7 by methylation. The products 5a, 5b and 5c were synthesized by independent methods. Hydrogenolysis of 2 led to the secondary amine 15 which was alkylated to the base of 16.
Synthesis of new guanidine derivatives from 2′,3′,4′,9′‐tetrahydrospiro[piperidine‐4,1′‐[1H]pyrido[3,4‐b]indole]
Authors: Domány Gy. , Gizur T. , Barta‐Szalai G. , Schön I. , Szántay Cs. , Hegedüs B.
Published: March 2009

The reaction of the isothiourea derivative 2 with methylaminc or pyrrolidine resulted in guanidines 3a‐3b. Using hydrazine under the same conditions the tetrazole derivative 4 was obtained. On reacting 2 with piperidine, morpholine, methylhydrazine, phenylhydrazine, hydroxylamine or sodium hydroxide, cycliza‐tion took place leading to the novel 4‐cyanimino‐1,2,3,4,6,7,12,12b‐octahydro‐3,12b‐ethanopyrim‐ido[1′,6′:1,2]pyrido[3,4‐b]indole (5). Some structural aspects of 5 and other model compounds were analysed mainly by 13C nmr spectroscopy.
Lewis acid assisted cyclization of arylcyanoguanidines to 2,4‐diaminoquinazolines
Authors: Jones Michael L. , Kuyper Lee F. , Styles Virgil L. , Caddell J. Marc
Published: March 2009

The mild preparation of N‐cyano‐N‐(1‐H‐indol‐5‐yl)guanidine and its cyclization to 1,3‐diamino‐7H‐pyrrolo[3,2‐f]quinazoline is described. Whereas previously reported methods of cyclization employed high temperatures to effect ring closure, we found that certain Lewis acids, such as boron trifluoride etherate, induce cyclization at moderate temperatures.
Synthesis of 2‐(1‐chloroalkyl)‐1,3‐benzodithioles and 2‐alkylidene‐1,3‐benzodithioles
Authors: Bellesia Franco , Boni Monica , Ghelfi Franco , Pagnoni Ugo M.
Published: March 2009

Boron trifluoride promoted transdithioacetalization of α‐chloroacetals with 1,2‐benzodithiol affords good yields of 2‐(1‐chloroalkyl)‐1,3‐benzodithioles, which dehydrochlorinates very satisfactorily to the corresponding 2‐alkylidene‐1,3‐benzodithioles.
Syntheses of substituted 1‐methyl‐2‐(1,3,4‐thiadiazol‐2‐yl)‐4‐nitropyrroles and 1‐methyl‐2‐(1,3,4‐oxadiazol‐2‐yl)‐4‐nitropyrroles
Authors: Firoozi F. , Javidnia K. , Kamali M. , Fooladi A. , Foroumadi A. , Shafiee A.
Published: March 2009

Starting from readily available ethyl‐4‐nitropyrrole‐2‐carboxylate (1), substituted 1‐methyl‐2‐(1,3,4‐thiadiazol‐2‐yl)‐4‐nitropyrroles and 1‐methyl‐2‐(1,3,4‐oxadiazol‐2‐yl)‐4‐nitropyrroles were prepared. The reaction of 1 with diazomethane gave ethyl 1‐methyl‐4‐nitropyrrole‐2‐carboxylate (2). Reaction of compound 2 with hydrazine hydrate afforded the corresponding hydrazide 3. The reaction of 3 with formic acid yielded 1‐(1‐methyl‐4‐nitropyrrole‐2‐carboxyl)‐2‐(formyl)hydrazine (7). Refluxing of the latter with phosphorus pentasulfide in xylene yielded compound 6 in 40% yield. Reaction of compound 7 with phosphorus pentoxide afforded compound 9. Reaction of compound 3 with 1,1′‐carboxyldiimidazole in the presence of triethylamine yielded 2‐(1‐methyl‐4‐nitro‐2‐pyrrolyl)‐1,3,4‐oxadiazoline‐4(H)‐5‐one (11). Refluxing compound 3 with cyanogen bromide in methanol gave compound 12. Compound 13 could be obtained through the reaction of compound 3 with carbon disulfide in basic medium. Alkylation of compound 13 afforded the correspanding alkylthio derivative 14. Reaction of 1‐methyl‐4‐nitropyrrole‐2‐carboxylic acid (15) with thiosemicarbazide and phosphorus oxychloride gave 2‐amino‐5‐(1‐methyl‐4‐nitro‐2‐pyrrolyl)‐1,3,4‐thiadiazole (16). Sandmeyer reaction of compound 16 yielded 2‐chloro‐5‐(1‐methyl‐4‐nitro‐2‐pyrrolyl)‐1,3,4‐thiadiazole (17). Refluxing of the latter with thiourea afforded 2‐(1‐methyl‐4‐nitro‐2‐pyrrolyl)‐1,3,4‐thiadiazoline‐4(H)‐5‐thione (18). Alkylation of compound 18 gave the corresponding alkylthio derivative 19. Oxidation of the latter with hydrogen peroxide in acetic acid yielded 2‐(1‐methyl‐4‐nitro‐2‐pyrrolyl)‐5‐methylsulfonyl‐1,3,4‐thiadiazole (20).
Synthesis and resolution of 2‐arylalkyl‐2‐(tetrazol‐5‐yl)‐N‐arylalkyl‐carboxamides. A new class of chiral sterically hindered tetrazole derivatives
Authors: Moriarty Robert M. , Levy Stuart G.
Published: March 2009

Chiral, racemic 2‐arylalkyl‐2‐(tetrazol‐5‐yl)‐N‐arylalkylcarboxamides 3 were conveniently prepared from ethyl cyanoacetate in four steps. The synthetic methodology developed is a facile way of introducing bulky substituents into a peptide‐like framework, affording intermediate α‐arylalkyl‐α‐amidonitriles. These nitriles were sufficiently activated to give, upon treatment with ammonium azide in dimethylformamide at 145° for twenty‐four to thirty hours, the corresponding tetrazoles in good yields. It has been determined that an optically pure α‐arylalkyl‐α‐amidonitrile epimerized to give diastereomeric products under the above conditions. A procedure for the fractional crystallization of the (S)‐(‐)‐α‐methylbenzylamine salts 4 of the tetrazoles to give the optically enriched tetrazoles 5 was also developed.
Preparation of trifluoromethylated pyrazoles and 1,4‐thiazine 1,1‐dioxides from trifluoromethylated sulfone derivatives
Authors: Takahashi Masahiko , Chigira Keiko
Published: March 2009

Trifluoromethylated sulfones, 3‐amino‐2‐arylsulfonyl‐4,4,4‐trifluoro‐3‐hydroxybutanenitrile (3) and 3‐(aroylmethyl)sulfonyl‐1,1,1‐trifluoropropane‐2,2,‐diols 12, were prepared and cyclized to 4‐arylsulfonyl‐5‐trifluoromethyl‐3‐hydrazinopyrazoles 9 and 5‐arylsulfonyl‐3‐trifluoromethyl‐3‐hydroxy‐2,3‐dihydro‐4H‐1,4‐thiazine 1,1‐dioxides 13, respectively.
Syntheses of substituted 1‐(2‐phenethyl)pyrazoles
Authors: Nazarinia M. , Sharifian A. , Shafiee A.
Published: March 2009

Alkylation of 3‐methylpyrazole with 2‐phenethyl p‐toluenesulfonate gave 3‐methyl‐1‐(2‐phenethyl)pyrazole (2a) and 5‐methyl‐1‐(2‐phenethyl)pyrazole (3a) in low yield. Reaction of 5‐chloro‐1,3‐dimethylpyrazole (5) with substituted‐benzaldehydes afforded compounds 7. Reduction of the latter afforded compound 2 in high yield. Compound 3 could be obtained from the reaction of substituted‐2‐(phenethyl)hydrazine hydrochloride 9 with acetoacetaldehyde dimethylacetal in moderate yield.
Studies on the reactivity and structure of phenyl 7‐fluoro‐4‐chromone‐3‐sulfonate
Authors: Löwe Werner , Bischoff Susan , Weber Manuela , Perpetuo Genivaldo , Luger Peter
Published: March 2009

The new, fluorinated benzoxathiinopyrazole 4 and the hitherto unknown fluorinated benzoxathiinodihydropyridine 5 can be produced by reacting the title compound 1 with cyanoacetic hydrazide (3) in the presence of sodium acetate. The structures of the compounds 4 and 5 were confirmed with the help of spectroscopic techniques, and their respective paths of formation have been discussed. The structure of the ester 1 was extensively studied by single crystal X‐ray analysis, then compared with that of the unfluorinated phenylsulfonate 2.
A facile synthesis of 3‐alkoxy phthalides by the palladium catalyzed carbonylative cyclization of o‐bromobenzaldehyde
Authors: Shim Sang Chul , Lee Dong Yub , Jiang Li Hong , Kim Tae Jeong , Cho Sung‐Dong
Published: March 2009

The palladium catalyzed carbonylative cyclization of o‐bromobenzaldehyde 1 in alcoholic solution gave 3‐alkoxyphthalides 3a‐e in 61–85% isolated yields via intramolecular cyclization induced by the coordinated formyl group on the palladium.
Amino acids in the synthesis of heterocyclic systems. Synthesis of γ‐(5‐(1,2,4‐Triazinylidene))‐α,β‐dehydro‐α‐amino acid derivatives and 6H‐pyrido[1,2‐d][1,2,4]triazin‐6‐ones
Authors: Stanovnik Branko , Tišler Miha , Čopar Anton
Published: March 2009

5‐(1,2,4‐Triazinyl) substituted enamines 3 react with 5(4H)‐oxazolones 4 in acetic anhydride to give acetylated products 5, while in toluene‐acetic acid mixture nonacetylated products 9 are formed. Both types of products were isolated as (E,Z) mixtures. Compounds 5 and 9 rearrange into 6H‐pyrido[1,2‐d]‐[1,2,4]triazin‐6‐ones 12 by heating in formic acid or in xylene, respectively. Compounds 5 are transformed in the presence of nucleophiles, such as sodium alkoxides or sodium amides via anionic form 10 into corresponding esters 13 and amides 14 of γ‐(5‐(1,2,4‐triazinylidene)) substituted derivatives of α‐amino‐2‐butenoic acid, which exist in 2‐(Z),4‐(Z) form.
Diels‐alder reactions of 2‐ and 3‐vinyl‐1‐(phenylsulfonyl)pyrroles
Authors: Xiao Dong , Ketcha Daniel M.
Published: March 2009

Regioselectively produced 2‐ and 3‐acetyl‐1‐(phenylsulfonyl)pyrroles can be reduced to the corresponding alcohols and subsequently dehydrated to afford N‐protected vinylpyrroles. These remarkably stable vinylpyrroles can then serve as heterodienes in [4 + 2] cycloaddition reactions with electron deficient dienophiles to afford tetrahydroindole derivatives.
The vilsmeier reaction in the synthesis of 3‐substituted [1]benzopyrano[4,3‐b]pyridin‐5‐ones. An unusual pyridine ring closure
Authors: Heber D. , Ivanov I. C. , Karagiosov S. K.
Published: March 2009

Starting from 4‐chlorocoumarin‐3‐carbaldehyde (1) and Wittig phosphoranes 2a‐d the title compounds 6a‐c have been synthesized via a four‐step sequence. The intermediate 4‐alkylamino‐3‐vinylcoumarins 5a‐k have been prepared by the reaction of 4‐chloro‐3‐vinylcoumarins 3a‐d with primary amines 4a‐h. The coumarin derivatives 5 (except 5k) underwent an unusual pyridine ring closure under Vilsmeier conditions to form the benzopyrano[4,3‐b]pyridines 6. When the aminoaldehydes 7 were treated with the Wittig reagent 2b the fused N‐alkyl‐2(1H)‐pyridinones 8 have been obtained as expected.
Synthesis of dibenzocrown ethers with pendant thioamide groups
Authors: Jang Youngchan , Bartsch Richard A.
Published: March 2009

The synthesis of eighteen crown ether compounds with pendant thioamide, N‐alkylthioamide, and N,N‐dialkylthioamide groups is reported. The new crown ether compounds are obtained by one‐step reactions from the corresponding sym‐dibenzo‐16‐crown‐5‐oxyacetamides and sym‐(propyl)dibenzo‐16‐crown‐5‐oxyacetamides with Lawesson's reagent.
A facile synthesis and spectral (ir, 1H, 13C, 31P nmr) studies of 2,10‐dichloro‐6‐aryloxy‐12H‐dibenzo[d,g][1,3,2]dioxaphosphocin 6‐sulfides
Authors: Devendranath Reddy C. , Mallikarjuna Reddy P. , Ramasubba Reddy D. , Nagalakshmamma M. , Anuradha K. , Raju C. Naga , Berlin K. Darrell , Couch Kevin M. , Tyagi Sameer
Published: March 2009

The synthesis of new 2,10‐dichloro‐6‐aryloxy‐12H‐dibenzo[d,g][1,3,2]dioxaphosphocin 6‐sulfides 4 was achieved in two steps with high yields from the simple materials 5,5′‐dichloro‐2,2′‐dihydroxydiphenyl‐methane (1) and thiophosphoryl chloride (2) which produced the key intermediate 2,6,10‐trichloro‐12H‐dibenzo[d,g][1,3,2]dioxaphosphocin 6‐sulfide (3). Treatment of 3 with substituted phenols under phase transfer catalytic (PTC) conditions led to members of 4. Long range coupling [5J(P,H) = 3.6 Hz] was observed between phosphorus and one of the bridged methylene protons in 4. A 13C nmr analysis revealed 2J(P,O,C), 3J(P,O,C) 4J(P,O,C) and 5J(P,O,C) couplings. All 31P nmr chemical shifts for thirteen members of these new heterocycles are reported for the first time. The nmr data are not totally definitive to confirm a boat‐chair as the major conformer for the central eight‐membered dioxaphosphocin ring, but such a conformer is tentatively suggested as favored.
A numerical measure of the degree of oxidation (DOX) of an organic molecule, with special attention to heteroatoms and heterocyclic compounds
Authors: Klemm L. H.
Published: March 2009

The degree of oxidation (DOX) of an organic compound CnHmEp, where E is any one or more of eleven elements more electronegative than hydrogen, is defined with respect to an alkane CnH2n+2 (DOX = 0) as a reference, One can calculate DOX either from the molecular or the structural formula of the compound by the relationship DOX = DU + p, where DU is the degree of unsaturation (i.e. index of hydrogen deficiency) in the molecule. The concept is developed for E is oxygen, and is extended to other chalcogens, as well as to halogens, nitrogen, phosphorus, and arsenic. Particular examples of heterocyclic compounds are considered. It is noted that addition of a simple hydride of E to an organic compound or elimination of the hydride from CnHmEp leaves DOX unchanged.
The synthesis of several novel triazine ring hydrolysis products of n‐[[(4‐methoxy‐6‐methyl‐1,3,5‐triazin‐2‐yl)amino]carbonyl]‐2‐(3,3,3‐trifluoropropyl)benzenesulfonamide
Authors: Heard Nina E. , Overman Monica C.
Published: March 2009

The syntheses of four hydrolysis products isolated from environmental studies on the title compound are reported. Spectral comparison of these synthetic standards with study isolates provided proof for sulfonyl urea intact triazine ring hydrolysis.
Propenethioamides in the synthesis of heterocyclic systems. Synthesis of pyrrole and 1,4‐thiazepine derivatives
Authors: Cocco Maria Teresa , Congiu Cenzo , Onnis Valentina
Published: March 2009

The reaction of propenethioamides 1 with bromoketones 2 and 3 led in acidic medium to the formation of 1,4‐thiazepines 6 and 7. The pyrrole derivatives 4 and 5 were obtained by reaction of 1 with 2 and 3 in basic medium.
The synthesis of cis‐6,12‐Diaryl‐6H,12H‐dibenzo[b,f][1,5]dithiocin‐6,12‐imine and cis‐6,12‐Diphenyl‐6,12‐epoxy‐6H,12H‐dibenzo[b,f][1,5]dithiocin
Authors: Brieaddy Lawrence E. , Donaldson Kelly H.
Published: March 2009

When treated with concentrated hydrochloric acid or heated beyond its melting point, the versatile thioimine 2 2‐mercaptobenzhydrylidenamine was unexpectedly converted to the title ring system. Also, this imine can be converted to 3‐phenyl‐1,2‐benzisothiazoles by prolonged exposure to air.
Sommelet‐hauser rearrangement of an ammonium ylide derived from the HIV‐1 reverse transcriptase inhibitor nevirapine
Authors: Klunder Janice M.
Published: March 2009

Functionalization at the 3‐position of the dipyridodiazepinone nevirapine (1) has been accomplished by Sommelet‐Hauser rearrangement of an ylide derived from 1. Treatment of N‐cyanomethylpyrrolidinium salt 4 with potassium tert‐butoxide in a mixture of dimethylsulfoxide and tetrahydrofuran at −10°, followed by acid hydrolysis, afforded a mixture of compounds 5 and 6 in a ratio of 1:1.8. Upon treatment of 4 with sodium amide in liquid ammonia, 5 and 6 were obtained in a ratio of 1.5:1 and a combined yield of 83%. Compound 5 is the desired product resulting from Sommelet‐Hauser rearrangement of 4, whereas 6 derives from competing Stevens rearrangement and intramolecular cyclization of the aldehyde produced upon hydrolysis. Baeyer‐Villiger oxidation of 5 afforded the 3‐hydroxy derivative 2, a recently identified metabolite of nevirapine.
Reaction of oligomethylene di(3‐oxobutanoate) with 1,1‐disubstituted alkenes and molecular oxygen in the presence of manganese(II and/or IE) acetate
Authors: Ouyang Jie , Nishino Hiroshi , Kurosawa Kazu
Published: March 2009

The reactions of 1,1‐disubstituted ethenes with oligomethylene di(3‐oxobutanoate) in the presence of manganese(II and/or III) acetate and atmospheric oxygen yielded an ω‐(3‐oxobutanoyloxy)alkyl 6,6‐diaryl‐3‐hydroxy‐3‐methyl‐1,2‐dioxane‐4‐carboxylate, oligomethylene di(6,6‐diaryl‐3‐hydroxy‐3‐methyl‐1,2‐dioxane‐4‐carboxylate)s, ω‐hydroxyalkyl 6,6‐diaryl‐3‐hydroxy‐3‐methyl‐1,2‐dioxane‐4‐carboxylates, an ω‐(3‐oxobutanoyloxy)alkyl 5,5‐diaryl‐2‐methyl‐4,5‐dihydrofuran‐3‐carboxylate, oligomethylene di(5,5‐diaryl‐2‐methyl‐4,5‐dihydrofuran‐3‐carboxylate)s, ω‐hydroxyalkyl 5,5‐diaryl‐2‐methyl‐4,5‐dihydrofuran‐3‐carboxylates, and an ohgomethylene diester bearing a substituted 1,2‐dioxane ring and a substituted 4,5‐dihydrofuran ring. The reaction of the 1,2‐dioxan‐3‐ols with acid gave the corresponding compounds bearing furan rings. The reaction of 1,1,6,6‐tetraaryl‐1,5‐hexadienes with oligomethylene di(3‐oxobutanoate) in the presence of manganese(III) acetate yielded macrocyclic diesters bearing two 4,5‐dihydrofuran rings.
New access to 4‐phenyl‐6H‐pyrrolo[1,2‐a]thieno[3,2‐f]‐[1,4]diazepines
Authors: Foloppe Marie‐Paule , Sonnet Pascal , Bureau Isabelle , Rault Sylvain , Robba Max
Published: March 2009

Pyrrolo[1,2‐a]thieno[3,2‐f][1,4]diazepines were obtained in an original one step synthesis by treatment of imines 1 with paraformaldehyde in refluxing ethanol. The intermediate Mannich bases were also converted into the thienooxadiazocines 12 and the diazepine N‐oxide 13.
5‐(α‐Fluorovinyl)tryptamines and 5‐(α‐Fluorovinyl)‐3‐(N‐methyl‐1′,2′,5′,6′,‐tetrahydropyridin‐3′‐ and ‐4′‐yl)indoles—5‐(α‐Fluorovinyl)tryptamines
Authors: Gharat Laxmikant A. , Martin Arnold R.
Published: March 2009

5‐(α‐Fluorovinyl)tryptamines 4a, 4b and 5‐(α‐fluorovinyl)‐3‐(N‐methyl‐1′,2′,5′,6′‐tetrahydropyridin‐3′‐ and ‐4′‐yl) indoles 5a, 5b were synthesized using 5‐(α‐fluorovinyl)indole (7). The target compounds are bioisosteres of 5‐carboxyamido substituted tryptamines and their tetrahydropyridyl analogs.
Synthesis of new azepino[3,4,5‐cd]indole derivatives
Authors: Hayes J. F. , Hayler J. D. , Walsgrove T. C. , Wicks C.
Published: March 2009

New 2‐oxoazepino[3,4,5‐cd]indole derivatives were formed by the reaction of the tosylate SK&F 98339 with N‐alkyl and N‐arylidenepropylamines in moderate yield.
An unusual formation of 1H‐s‐triazole N‐imines from reactions of 1,3,4‐oxadiazin‐6‐ones and nitrilimines
Authors: Argyropoulos Nikolaos G. , Corobili Ecaterini , Raptopoulou Ecaterini P.
Published: March 2009

A new, unusual way to obtain polysubstituted 1H‐S‐triazole N‐imine derivatives is described from reactions of the readily available 1,3,4‐oxadiadin‐6‐one derivatives and nitrilimines. Besides an hydrazide derivative of phenylglyoxylic acid is also formed. Both adducts were characterised by X‐ray crystal structure analysis.
1,4‐Benzoxazin‐2‐ones, benzo[d]oxazoles and 2H‐1,4‐benzoxazines from the reaction of 2‐(methoxyimino)benzen‐1‐ones with arylacetates, arylacetic acids and trans‐ stilbene
Authors: Nicolaides Demetrios N. , Awad R. Wajih , Varella Evangelia A.
Published: March 2009

10‐(Methoxyimino)phenanthrene‐9‐one 1 reacts thermally with the arylacetic derivatives 2(a‐j) to yield the corresponding 1,4‐benzoxazin‐2‐ones 4(a‐d,f) and benzo[d]oxazoles 5(a‐e,g). Similarly, reaction of the monoximes 7a, 7b with compounds 2a, 2d respectively affords 8a, 8b, while action of trans‐stilbene on the monoximes 1, 7a, 7b leads to the 1,4‐benzoxazines 10, 11, 13, obtained along with the corresponding 2‐phenyloxazoles 5a, 8a, 8c and compound 12.
Transformations of the pyrido[1,2‐a]pyrazine ring system into imidazo[1,2‐a]pyridines, imidazo[1,2‐a]pyrimidines and 2‐oxa‐6a, 10c‐diazaaceanthrylenes
Authors: Kolar Patrik , Tišler Miha , Pizzioli Alessandro
Published: March 2009

Transformations of methyl 3‐dimethylamino‐2‐(1‐methoxycarbonyl‐4‐oxo‐4H‐pyrido[1,2‐a]pyrazin‐3‐yl)acrylate with some cyanomethylenecarbonyl group containing compounds or cyanamide into imidazo‐[1,2‐a]pyridines, irmdazo[1,2‐a]pyrimidines and 2‐oxa‐6a, 10c‐diazaaceanthrylenes are described.
17O NMR studies of electronic and steric interactions of substituted quinoxaline‐2(1H),3(4H)‐diones
Authors: Gerothanassis Ioannis P. , Varvounis George
Published: March 2009

17O nmr studies, at natural abundance, of substituted quinoxaline‐2(1H),3(4H)‐diones demonstrate that the 17O chemical shift data can provide new insights into steric and electronic interactions due to long range substituent effects on the aromatic ring. The role of considerable “keto” character and torsion angle deformation of the diamide group in solution is emphasized.
Adducts of phenanthrene 9,10‐imine and of benz[a]anthracene 5,6‐imine to some nitrogen heterocycles
Authors: Shalom Yosef , Blum Jochanan , Harvey Ronald G.
Published: March 2009

N‐4‐Pyridinyl‐, N‐2‐quinolinyl‐, and 2‐pyrazinylphenanthrene 9,10‐imines 4–6, as well as N‐4‐pyridinyl‐ and N‐2‐pyrazinylbenz[a]anthracene 5,6‐imines 12 and 13 were prepared by sodium hydride‐mediated interaction of the parent arene imines, 1 and 10, and the respective chloropyridine, chloroquinoline or chloropyrazine. N‐Nicotynoyl‐, N‐2‐pyridinoyl‐ and N‐6‐quinolinoylphenanthrene 9,10‐imines 7–9 were obtained by interaction of N‐trimethylsilylphenanthrene 9,10‐imine (2) and the appropriate pyridine‐ or quinolinecarbonyl chlorides. Reaction of N‐methylsulfonylphenanthrene 9,10‐imine with thymine, cytosine, 5‐fluorocytosine, purine, 6‐chloropurine and adenine afforded, in the presence of either potassium carbonate or 1,5‐diazabicyclo[3.4.0]non‐5‐ene, adducts 16–22, respectively. The structures of the adducts were conformed by multinuclear nmr and by NOESY and C‐H correlation 2D nmr spectrometry.
Aminonitropyridines and their N‐oxides
Authors: Hollins Richard A. , Merwin Lawrence H. , Nissan Robin A. , Wilson William S. , Gilardi Richard
Published: March 2009

2,6‐Diamino‐3,5‐dinitropyridine 1‐oxide has been prepared by mixed acid nitration of 2,6‐diaminopyridine, followed by oxidation using hydrogen peroxide in acetic acid. 3,5‐Dinitro‐2,4,6‐triaminopyridine has been prepared by oxidative amination of 2‐chloro‐3,5‐dinitropyridine or 2,6‐diamino‐3,5‐dinitropyridine using potassium permanganate in liquid ammonia, or by “vicarious nucleophilic amination” of 2,6‐diarnino‐3,5‐dinitropyridine using hydroxylamine in aqueous potassium hydroxide. 3,5‐Dinitro‐2,4,6‐triaminopyridine 1‐oxide has been prepared by oxidation of 3,5‐dinitro‐2,4,6‐triaminopyridine using hydrogen peroxide in acetic acid, and by “vicarious nucleophilic amination” of 2,6‐diamino‐3,5‐dinitropyridine 1‐oxide. Nmr spectroscopy and single crystal X‐ray diffraction studies have shown that these compounds have the planar structures and intra‐ and inter‐molecular hydrogen bonding necessary to confer on the materials the high density, the thermal and chemical stability, and the explosive insensitivity required for new insensitive energetic materials.
Synthesis and structure elucidation of new cytotoxic azathioxanthones
Authors: Varvaresou A. , Tsotinis A. , Papadaki‐Valiraki A. , Siatra‐Papastaikoudi Th.
Published: March 2009

A series of new cytotoxic azathioxanthones 7a‐h was synthesized and characterized by their spectral data.
Efficient syntheses and crystal structures of new benzene‐containing cryptands
Authors: Bordunov Andrei V. , Dalley N. Kent , Kou X. , Bradshaw Jerald S. , Pastushok Victor N.
Published: March 2009

Seven new cryptands 3–9 containing two or three aromatic rings in one bridge were prepared in good yields by treating N,N'‐bis(p‐chlorophenol)‐substituted diaza‐18‐crown‐6 (2) with three oligoethylene glycol ditosylates, 1,3‐propanediol ditosylate, 2,6‐pyridinedimethanol ditosylate, α,α'‐dibromo‐o‐xylene and α,α'‐dibromo‐p‐xylene. Because of the convenient synthesis of 2 from N,N'‐bis(methoxymethyl)diaza‐18‐crown‐6 (1) and the relative ease of isolation of the cryptand products, this is an excellent method for the design of three‐dimensional cavities containing aromatic fragments. In an attempt to better understand the synthetic route to the cryptands, the crystal structures of KI·2 and Na Picrate·2 were determined using X‐ray analysis. In addition, crystal structure analyses of cryptands 3, 6 and 8 were used to establish their structures.
Pyrimidines. XXXIII. Synthesis and properties of new fervenulin derivatives
Authors: Werner‐Simon Susanne , Pfleiderer Wolfgang
Published: March 2009

A series of new 3‐substituted fervenulin (6,8‐dimethylpyrimido[5,4‐c]‐1,2,4‐triazine‐5,7‐dione) (1) derivatives have been synthesized by modifying the 3‐alkyl‐ and aralkyl side‐chains. Brominations of 3‐methyl‐15, 3‐ethyl‐16‐ and 3‐benzylfervenulin (17) led to mono‐ and dibromo derivatives 22, 23, 25–27, which are prone to various nucleophilic displacement reactions 24, 28–35. Periodate oxidation and ozonolysis, respectively, of 3‐styrylfervenulin (20) afforded fervenulin‐3‐carboxaldehyde (36) which was transformed to a folic acid analog (39). Potassium permanganate oxidation of 3‐alkylfervenulins 15–19 afforded only ring‐contraction to 3‐alkyl‐5,7‐dimethylimidazo[4,5‐e]‐1,2,4‐triazin‐6‐ones 42–46 which are also formed as mixtures with its 2,4a‐dihydro derivatives 47–50 on treatment with ethanolic sodium hydroxide. Fervenulin‐3‐carboxylic acid (55) can be converted to the corresponding acid chloride 58 which reacts with amines to fervenulin‐3‐carboxamides 59, 64–67 and/or 2,4a‐dihydro‐5,7‐dimethylimidazo[4,5‐e]‐1,2,4‐triazin‐6‐one‐biscarboxamides 60–64.
9‐Substituted acridines. Demethoxylation of 9‐methoxyacridine and dechlorination of 9‐chloroacridine in hydroxylic solvents
Authors: Kalatzis Evangelos , Konga Zoi , Geronikolou Konstantina
Published: March 2009

In methanol‐water mixtures containing sodium or potassium hydroxide (up to 2.00M) the demethoxylation of 9‐methoxyacridine to 9‐acridone is of first order in both the free form of 9‐methoxyacridine and the hydroxyl ion. The rate of the reaction is increased with an increase in the concentration of water. Sodium perchlorate has a small retarding effect on the reaction. In methanol‐water mixtures containing perchloric or hydrochloric acid (up to 3.45M) the demethoxylation is of first order with respect to the protonated form of 9‐methoxyacridine. The rate of the reaction decreases with an increase in the concentration of the acid or of sodium perchlorate, but when the concentration of water is increased (≈︁1.7 to 50M) and that of the acid is not changed, it reaches a maximum value in mixtures containing 8 to 10M‐water. The dechlorination of 9‐chloroacridine to 9‐methoxyacridine in methanol containing sodium hydroxide or methoxide (up to 0.31 M) is of first order in both the 9‐chloroacridine and the hydroxyl or methoxyl ions.
Synthesis and biological evaluation of some 4‐(isoxazolinyl or 1,2,4‐oxadiazolyl) coumarins
Authors: Nicolaides Demetrios N. , Fylaktakidou Konstantina C. , Litinas Konstantinos E. , Hadjipavlou‐Litina Dimitra
Published: March 2009

Reaction of compound 3 with nitrile oxide 4a affords compounds 5a and 6 in 73% and 3% yield respectively, while reaction of 3 with 4b affords only compound 5b (85%). Reactions of compound 8 with the nitrile oxides 4a,b result in compounds 9a,b. The compound 10, prepared from 1 and O‐methylhydroxylamine, reacts with nitrile oxide 4b to give the oxadiazole derivative 12. The above referred coumarins are screened for antiinflammatory activity in vivo using the carrageenin rat paw edema and in vitro through their antiproteolytic activity and their ability to inhibit β‐glucuronidase and 12‐Lipoxygenase.
A novel photoaddition of 2‐phenylbenzimidazole
Authors: Jones Richard H. , Ramsden Christopher A. , Rose Helen L.
Published: March 2009

Irradiation of 2‐phenylbenzimidazole (3) in the presence of methyl acrylate (20 equivalents) using a medium pressure mercury lamp gives methyl 2‐(2‐phenylbenzimidazol‐1‐yl)propionate (4) (75%) whose structure has been confirmed by an X‐ray analysis. A similar reaction using acrylonitrile gave only a low yield (1%) of the corresponding propionitrile derivative 5. A mechanism involving photoexcitation of 2‐phenylbenzimidazole (3) followed by sequential single electron transfer, proton transfer and radical coupling is proposed to account for the formation of the novel photoadducts 4 and 5.
Furopyridines. XVII. Cyanation, chlorination and nitration of furo[3,2‐b]pyridine N‐oxide
Authors: Shiotani Shunsaku , Taniguchi Katsunori
Published: March 2009

The N‐oxide 2 of furo[3,2‐b]pyridine (1) was cyanated by the Reissert‐Henze reaction with potassium cyanide and benzoyl chloride to give 5‐cyano derivative 3, which was converted to the carboxamide 4, carboxylic acid 5, ethyl ester 6 and ethyl imidate 8. Chlorination of 2 with phosphorus oxychloride yielded 2‐9a, 3‐ 9b, 5‐ 9c and 7‐chloro derivative 9d. Reaction of 9d with sodium methoxide, pyrrolidine, N,N‐dimethylformamide and ethyl cyanoacetate afforded 7‐methoxy‐ 10, 7‐(1‐pyrrolidyl)‐ 11 and 7‐dimethylaminofuro[3,2‐b]pyridine (14) and 7‐(1‐cyano‐1‐ethoxy‐carbonyl)methylene‐4,7‐dihydrofuro[3,2‐b]pyridine (12). Nitration of 2 with a mixture of fuming nitric acid and sulfuric acid gave 2‐nitrofuro[3,2‐b]pyridine N‐oxide (15).
Studies on pyrrolidinones. synthesis of N‐(2‐nitrobenzyl)pyroglutamic acid
Authors: Rigo BenoǏT , Dolaine RÉGis , Ghammarti Samira El , Couturier Daniel
Published: March 2009

While methyl N‐(4‐nitrobenzyl)pyroglutamate can be obtained from methyl N‐trimethylsilylpyroglutamate, the best way to obtain methyl N‐(2‐nitrobenzyl)pyroglutamate is to react 4‐nitro benzyl bromide with the iminoether derived from methyl pyroglutamate.
Haloacetylated enol ethers. 6 [5]. Synthesis of 4,5‐trimethylene‐4,5‐dihydroisoxazoles
Authors: Martins Marcos A. P. , Flores Alex F. C. , Freitag Rogério A. , Zanatta Nilo
Published: March 2009

The investigation of the effect of the cyclopentane ring on the regiochemistry of the reactions of 2‐acetylcyclopentanones 1a‐d and β‐methoxyvinyl trifluoromethyl ketone derivative 2a with hydroxylamine hydrochloride is reported. The reactions give regiospecifically the 4,5‐trimethylene‐4,5‐dihydroisoxazoles 3a‐d in good yields.
Synthesis of some 6‐S‐heterocyclic derivatives of 1,2:3,4‐di‐O‐isopropylidene‐α‐D‐galactopyranose
Authors: Alho M. A. Martins , D'Accorso N. B. , Thiel I. M. E.
Published: March 2009

We applied nucleophilic substitution to 6‐O‐tosyl‐1,2:3,4‐di‐O‐isopropylidene‐α‐D‐galactopyranose using sulphur nucleophiles and obtained 6‐S‐derivatives of 1,2:3,4‐di‐O‐isopropylidene‐α‐D‐galactopyranose. We present the physical and spectroscopic characterization of these heterocyclic compounds as well as other related compounds obtained by substitution, using other substrates. The conformational studies of all products are presented and discussed.
Synthesis and characterization of new 1,1′‐diester, diketone, and dinitrile derivatives of 2,2′‐biimidazole
Authors: Barnett Mark , Secondo Paula , Collier Harvest
Published: March 2009

Substituted 1,1′‐diester, diketone and dinitrile derivatives are prepared from 2,2′‐biimidazole. The reactions involved include: Michael addition with halogenated olefins; nucleophilic substitution with ketones, nitriles, and esters; and condensation with amines.
Synthesis of [1,3,4]thiadiazolo[3,2‐a]pyrimidines in the presence of formic acid
Authors: Takenaka Keiko , Tsuji Tadakazu
Published: March 2009

Formic acid‐phosphorus pentoxide was effective for the preparation of 5,7‐dimethyl[1,3,4]thiadiazolo‐ and ‐[1,3]thiazolo[3,2‐a]pyrimidin‐4‐ium salts. Further, the pyrimidine ring transformation and the isocyanation of 5imino‐6H‐[1,3,4]thiadiazolo‐ and ‐[1,3]thiazolo[3,2‐a]pyrimidin‐7‐ones were carried out in the presence of formic acid and triethyl orthoformate, respectively.
Alkylation of non‐electron rich nitrogen heterocycles by alkyl orthoformates: Quantum chemistry calculations
Authors: Guccione Salvatore , Russo Filippo , Langer Thierry
Published: March 2009

Results of semiempirical MO calculations of N1‐ and N2‐alkyl pyrazolotriazolopyrimidin‐4‐ones originating from alkylation by trimethyl and triethyl orthoformate are presented.
Synthesis of 3‐glycosyl‐5‐substituted‐2‐isoxazolines
Authors: Fascio Mirta L. , D'Accorso Norma B.
Published: March 2009

The synthesis of eight 3‐glycosyl‐5‐substituted‐2‐isoxazolines is described. They are obtained by 1,3‐dipolar cycloaddition from some 2‐deoxy‐sugar oximes. A side product was isolated. The physical and spectroscopycal characterization of all compounds are reported.
Reaction of 4,5‐dichloro‐3‐nitropyridazin‐6‐one with dimethylchloromethyleneammonium chloride
Authors: Kweon Deok‐Heon , Cho Su‐Dong , Kirn Sung‐Kyu , Chung Joo‐Wha , Yoon Yong‐Jin
Published: March 2009

3,4,5‐Trichloropyridazin‐6‐one, 3,4,5,6‐tetrachloropyridzine and 4,5‐dichloro‐3‐(N,N‐dimethylamino)‐pyridazin‐6‐one were synthesized from 4,5‐dichloro‐3‐nitropyridazin‐6‐one and dimethylchloromethylene‐ammonium chloride selectively.
Saturated heterocycles. 242. Synthesis of 2‐substituted‐6‐(6′,7′‐dimethoxy‐3′,4′‐dihydro‐1′‐isoquinolyl)‐5,6,7,8‐tetrahydro‐ quinazolin‐4(3H)‐one Derivatives
Authors: Bernáth Gábor , Lázár János , Fülöp Ferenc , Kóbor Jenó
Published: March 2009

In the reactions of the recently synthesized β‐ketoesters 1‐[(3′‐methoxycarbonyl‐ and 1‐[(3′‐ethoxycarbonyl‐4′‐oxo)‐1′‐cyclohexyl]‐3,4‐dihydroisoquinoline 4, 5 with amidines or cyclic guanidines, a number of 2‐substituted‐6‐(6′,7′‐dimethoxy‐3′,4′‐dihydro‐1′‐isoquinolyl)‐5,6,7,8‐tetrahydroquinazolin‐4(3H)‐one derivatives 6–8 were prepared. The new compounds possess various pharmacological actions.
Novel pyrrole‐annulated heterocyclic systems. Synthesis of 10H‐pyrrolo[1,2‐b][1,2,6]benzothiadiazocin‐11(12H)‐one 5,5‐dioxide
Authors: Santo Roberto Di , Costi Roberta , Artico Marino , Massa Silvio
Published: March 2009

Intramolecular cyclization of 1‐(2‐aminophenylsulfonyl)‐1H‐pyrrole‐2‐acetic acid 5 gave 10H‐pyirolo[1,2‐b][1,2,6]benzothiadiazocin‐11(12H)‐one 5,5‐dioxide 4, a novel heterocyclic system of pyrrolobenzothiadiazocine family. Compound 5 was obtained starting from 2‐nitrobenzenesulfonyl chloride with ethyl 1H‐pyrrole‐2‐(α‐oxo)acetate, which were condensed to afford 1‐(2‐nitrophenylsulfonyl)‐1H‐pyrrole‐2‐(α‐oxo)acetate 13. Reduction of 13 gave the amino ester 7, which was hydrolyzed to the required aminoacid 5. The synthesis of 7‐chloro‐10H‐pyrrolo[1,2‐b][1,2,6]benzothiadiazocin‐11(12H)‐one 5,5‐dioxide 16 is also described.
Stereoselective synthesis of 2β‐carbomethoxy‐3β‐phenyltropane derivatives. Enhanced stereoselectivity observed for the conjugate addition reaction of phenylmagnesium bromide derivatives with anhydro dichloromethane
Authors: Xu Lifen , Trudell Mark L.
Published: March 2009

The use of dichloromethane as a solvent for the conjugate addition reaction of preformed etheral solutions of phenylmagnesium bromide derivatives with anhydroecgonine methyl ester (2) was found to enhance the stereoselectivity of the reaction and provide the 2β‐carbomethoxy‐3β‐phenyltropane derivatives 3a‐d in high yield.
Synthesis of a 9‐acridinyl nonapeptide containing the DNA recognizing region of 434 phage repressor protein
Authors: Takenaka Shigeori , Iwamasa Kenji , Takagi Makoto , Nishino Norikazu , Mihara Hisakazu , Fujimoto Tutomu
Published: March 2009

A peptide‐intercalator conjugate was synthesized by connecting acridine with a Gln‐Gln‐Ser‐Ile‐Glu‐Gln‐Leu‐Glu‐Asn sequence representing the DNA recognizing region of 434 phage repressor protein. This conjugate 7 binds to DNA in spite of its anionic character with the aid of the intercalator.
Synthesis of new dihydrooxathiino[2,3‐b]quinoline
Authors: Hahn Hoh‐Gyu , Chang Kee Hyuk , Lee Wha Suk , Yoo Ji Uk
Published: March 2009

A synthesis of new dihydrooxathiinoquinoline 4 is described. The key compound 6 was prepared by known methods from acetoacetanilide 1. A condensation of β‐chlorosulfide 6 in 75% aqueous sulfuric acid gave quinolone 5. Conversion of 5 to 4 was achieved by treatment with potassium hydroxide in ethanol solution.
2,4,6‐trichloropyrimidine. Reaction with 4‐substituted phenolate ions
Authors: Delia Thomas J. , Nagarajan A.
Published: March 2009

A systematic investigation of the reactivity of 2,4,6‐trichloropyrimidine with phenoxide nucleophiles has been conducted. Conditions have been described which lead to mono‐, di‐, and trisubstituted‐pyrimidines. Unexpected product distributions for mono‐ and disubstituted products were observed and explanations for these results are offered.
Synthesis and central nervous system stimulant activity of 5,8‐methanoquinazolines fused with 1,2,4‐triazole, tetrazoleand 1,2,4‐triazine
Authors: Nagai Shin‐Icbi , Ueda Taisei , Sugiura Satoe , Nagatsu Akito , Murakami Nobutoshi , Sakakibara Jinsaku , Fujita Michiko , Hotta Yoshiki
Published: March 2009

5,8‐Methanoquinazolines fused with 1,2,4‐triazole 4–5, tetrazole 6, and 1,2,4‐triazine 8 were prepared starting from 2‐hydrazino‐5,8‐methanoquinazoline 3. Compound 3 and 6 showed the most potent central nervous system (CNS) stimulant activities.
Reaction of 5‐aminopyrazoles with β‐dimethylaminopropiophenones. Synthesis of new pyrazolo[3,4‐b]pyridines
Authors: Quiroga J. , Insuasty B. , Cruz S. , Hernandez P. , Bolaños A. , Moreno R. , Hormaza Angelina , de Almeida Regina H. S.
Published: March 2009

Several new pyrazolo[3,4‐b]pyridines were obtained from the reaction of 5‐amino‐1‐aryl‐3‐methylpyrazoles 1 with β‐dimemylaminopropiophenones 2 in pyridine. The structure elucidation of 4,5‐dihydropyrazolo[3,4‐b]pyridines 3 is based on nmr measurements and X‐ray diffraction. The treatment of compounds 3 with N‐bromosuccinimide led to the formation of pyrazolo[3,4‐b]pyridines 4.
Reaction of N1,N2‐diarylacetamidines with (2,4,7‐trinitro‐9H‐fluoren‐9‐ylidene)propanedinitriles
Authors: Gomaa Mohsen Abdel‐Motaal , Döpp Dietrich
Published: March 2009

Novel spiro[fluorene‐9,4′‐(1′,2′,3′,4′‐tetrahydropyridine)]‐5′‐carbonitriles 6a‐c have been obtained from the reaction of N1,N2‐diarylacetamidines 1a‐c with (2,4,7‐trinitro‐9H‐fluoren‐9‐ylidene)propanedinitrile (2) in ethyl acetate solutions at ambient temperature for 6a,b or under reflux for 6c, respectively.
Synthesis of 1‐methyl‐7‐(trifluoromethyl)‐1H‐pyrido[2,3‐c][1,2]thiazin‐4(3H)‐one 2,2‐dioxide
Authors: Coppo Frank T. , Fawzi Maged M.
Published: March 2009

The reaction of methyl 2‐bromo‐6‐(trifluoromethyl)‐3‐pyridinecarboxylate (1) with methanesulfonamide gave methyl 2‐[(methylsulfonyl)amino]‐6‐(trifluoromethyl)‐3‐pyridine‐carboxylate (2). Alkylation of compound 2 with methyl iodide followed by cyclization of the resulting methyl 2‐[methyl(methylsulfonyl)amino]‐6‐(trifluoromethyl)‐3‐pyridinecarboxylate (3) yielded 1‐methyl‐7‐(trifluoromethyl)‐1H‐pyrido[2,3‐c][1,2]thiazin‐4(3H)‐one 2,2‐dioxide (4). The reaction of compound 4 with α,2,4‐trichlorotoluene, methyl bromopropionate, methyl iodide, 3‐trifluoromethylphenyl isocyanate, phenyl isocyanate and 2,4‐dichloro‐5‐(2‐propynyloxy)phenyl isothiocyanate gave, respectively, 4‐[(2,4‐dichlorophenyl)methoxy]‐1‐methyl‐7‐(trifluoromethyl)‐1H‐pyrido[2,3‐c][1,2]thiazine 2,2‐dioxide (5), methyl 2‐[[1‐methyl‐2,2‐dioxido‐7‐(trifluoromethyl)‐1H‐pyrido[2,3‐c][1,2]thiazin‐4‐yl]oxy]propanoate (6), 1,3,3‐trimethyl‐7‐(trifluoromethyl)‐1H‐pyrido[2,3‐c][1,2]thiazin‐4(3H)‐one 2,2‐dioxide (7), 4‐hydroxy‐1‐methyl‐7‐(trifluoromethyl)‐N‐[3‐(trifluoromethyl)phenyl]‐1H‐pyrido[2,3‐c][1,2]thiazine‐3‐carboxamide 2,2‐dioxide (8), 4‐hydroxy‐1‐methyl‐7‐(trifluoromethyl)‐N‐phenyl‐1H‐pyrido[2,3‐c][1,2]thiazine‐3‐carboxamide 2,2‐dioxide (9) and N‐[2,4‐dichloro‐5‐(2‐propynyloxy)phenyl]‐4‐hydroxy‐1‐methyl‐7‐(trifluoromethyl)‐1H‐pyrido[2,3‐c][1,2] thiazine‐3‐carboxamide 2,2‐dioxide (10).
The reactions of heterocyclic isothiocyanates bearing an ortho ester group with aminoalcohols
Authors: Urleb Uroš
Published: March 2009

Heterocyclic isothiocyanates 1,5,9, bearing an o‐ester group were converted to thiourea derivatives 2a‐c, 6a‐b, and 10a‐b, respectively, using β‐aminoalcohols, and to the fused ring systems, e.g., thieno[3,2‐d]pyrimidine 4a‐b, pyrido[2,3‐d]pyrimidine 8, pteridine 11a, thiazolo[3,2‐a]pyrido[2,3‐d]pyrimidine 7a‐b, and thiazolo[3,2‐a]mieno[3,2‐d]pyrirnidine 3a‐c, derivatives.
Synthesis and antibacterial activity of 1‐(substituted‐benzyl)‐6‐fluoro‐1,4‐dihydro‐4‐oxoquinoline‐3‐carboxylic acids and their 6,8‐difluoro analogs
Authors: Sheu Jia‐Yuh , Chen Yeh‐Long , Fang Kuo‐Chang , Wang Tai‐Chi , Tzeng Cherng‐Chyi , Peng Chien‐Fang
Published: March 2009

Alkylation of 6,7‐difluoro‐4‐hydroxyquinoline‐3‐carboxylic acid ethyl ester with substituted‐benzyl chlorides gave 1‐(substituted‐benzyl)‐6,7‐difluoro‐1,4‐dihydro‐4‐oxoquinoline‐3‐carboxylic acid ethyl esters. Their treatment with piperazine or N‐methylpiperazine in pyridine yielded 1‐(substituted‐benzyl)‐6‐fluoro‐1,4‐dihydro‐4‐oxo‐7‐(l‐piperazinyl)quinoline‐3‐carboxylic acid ethyl esters which were hydrolyzed with aqueous sodium hydroxide and then acidified with hydrochloric acid afforded the desired 1‐(substituted‐benzyl)‐6‐fluoro‐1,4‐dihydro‐4‐oxo‐7‐(1‐iperazinyl)quinoline‐3‐carboxylic acids. The 6,8‐difluoro analogs were prepared similarly using 6,7,8‐trifluoro‐4‐hydroxyquinoline‐3‐carboxylic acid ethyl ester as a starting material. Some of these quinolones demonstrated fairly good antibacterial activities. Among them, 6‐fluoro‐1‐(4‐fluorophenylmethyl)‐1,4‐dihydro‐7‐(1‐iperazinyl)‐4‐oxoquinoline‐3‐carboxylic acid (7d) and 6,8‐difluoro‐1‐(3‐fluorophenylmethyl)‐1,4‐dihydro‐7‐(1‐piperazinyl)‐4‐oxoquinoline‐3‐carboxylic acid (8c) are two of the best.
New supramolecular transition metal catalysts
Authors: Reetz Manfred T.
Published: March 2009

The covalent connection of a catalytically active transition metal center with a water‐soluble receptor (host molecule) generates a new type of supramolecular catalyst in which the features of molecular recognition, phase transfer catalysis and transition metal catalysis are combined in a single system. The first examples of this principle make use of commercially available β‐cyclodextrin (β‐CD) as the receptor and rhodium complexes of diphosphanes as the catalytically active center, these being covalently connected to one another via a spacer. In competitive hydrogenation of certain olefins, unusual degrees of substrate selectivity based on molecular recognition are observed, not possible by conventional transition metal catalysts. The two‐phase (water/organic) hydrogenation of nitro‐aromatics also is a smooth process catalyzed by these supramolecular complexes. They also constitute an unusually active catalyst system for the selective hydroformylation of higher olefins such as 1‐octene in a two‐phase system. Dendrimers having diphosphane moieties on the surface provide ligands for transition metals, the corresponding metal complexes (e.g., Pd) functioning as efficient catalysts which can be recycled due to their nanoscopic properties.
Synthesis, characterization and in vitro anthelmintic activity against Nippostrongylus brasiliensis of new 5‐aryl‐2‐phenyl‐6,7‐dihydropyrazolo[1,5‐a]pyrimidines
Authors: Quiroga Jairo , Insuasty Braulio , Hormaza Angelina , Gamenara Daniela , Dominguez Laura , Saldaña Jenny
Published: March 2009

Several new pyrazolo[1,5‐a]pyrimidines were obtained from the reaction of 1H‐5‐amino‐3‐phenylpyrazole (1) with β‐dimethylaminopropiophenones 2 in pyridine. The structure elucidation of 6,7‐dihydropyrazolo[1,5‐a]pyrimidines 3 is based on nmr measurements. These compounds showed moderate anthelmintic in vitro activity against the Nipposirongylus brasiliensis model.
Haloacetylated enol ethers. 13. Synthesis of N‐[1‐aryl(alkyl)‐3‐oxo‐4,4,4‐trichloro‐1‐buten‐1‐yl]‐o‐phenylenediamines and 2‐trichloromethyl‐4‐aryl‐3H‐1,5‐benzodiazepines
Authors: Bonacorso Helio Gauze , Bittencourt Sandra R. T. , Wastowski Arci D. , Wentz Alexandre P. , Zanatta Nilo , Martins Marcos A. P.
Published: March 2009

The synthesis and isolation of the intermediates N‐[1‐aryl(alkyl)‐3‐oxo‐4,4,4‐trichloro‐1‐buten‐1‐yl]‐o‐phenylenediamines 2a‐f and the corresponding 2‐trichloromethyl‐4‐aryl‐3H‐1,5‐benzodiazepines 3c‐g or benzimidazoles 4a‐b derivatives obtained from the intramolecular cyclization of 2a‐f or from direct cyclo‐condensation reaction of β‐alkoxyvinyl trichloromethyl ketones 1a‐g with o‐phenylenediamine, is reported. Depending of the structure of the β‐alkoxyvinyl trichloromethyl ketones or the N‐[1‐aryl(alkyl)‐3‐oxo‐4,4,4‐trichloro‐buten‐1‐yl]‐o‐phenylenediamines and the reactions conditions, benzimidazoles or 3H‐1,5‐benzodiazepines were obtained.
Synthesis and characterization of some heterocyclic derivatives from 1,2:3,4‐Di‐o‐isopropylidene‐α‐d‐galacto‐1,6‐hexadialdo‐1,5‐pyranose oxime
Authors: Alho M. A. Martins , D'accorso N. B.
Published: March 2009

We report the synthesis of 5‐[5′‐(1′,2′:3′,4′‐di‐O‐isopropylidene‐β‐L‐arabinopyranosyl)]tetrazole, from 1,2:3,4‐di‐O‐isopropylidene‐α‐D‐galacto‐1,6‐hexodialdo‐1,5‐pyranose oxime via 1,2:3,4‐di‐O‐isopropylidene‐α‐D‐galcturononitrile as intermediate by 1,3‐dipolar cycloaddition. We also report the synthesis of 5‐methyl‐ and 5‐phenyl‐2‐[5′‐(1′,2′:3′,4′‐di‐O‐isopropylidene‐β‐L‐arabinopyranosyl)]‐1,3,4‐oxadiazole from the tetrazole derivative.

The physical and spectroscopic characterizations of the heterocyclic derivatives as well as the intermedi ate nitrile and the principal by product are described and we discuss its possible formation pathway. We present the preferential conformation in solution using computational calculation and spectroscopic data.