Ring open analogues of deoxynucleotides

The synthesis of acyclic analogues of 2′-deoxyadenosine and 2′-deoxythymidine which lack only the 2′-CH₂ of the sugar is described. The synthesis of dinucleotides from these analogues is also described.     

Synthesis of new pyridine intermediates as precursors for the elaboration of streptonigrin analogues by the metalation-cross-coupling strategy

Starting from available 2-amino-6-chloro-3-nitropyridine, synthesis of 3-amino-6-pyridinecarboxylic acid derivatives precursor for pyridine ring C of streptonigrin analogues is described.     

A new synthesis of atanine,khaplofoline and their analogues

A facile synthesis of Atanine, Khaplofoline and their analogues is described. The method involves condensation of an appropriately substituted 2-quinolone-3-acetic acid with isobutryaldehyde, as the starting point.     

Synthesis of difluorinated carbocyclic analogues of 5-deoxypentofuranoses

The synthesis of difluorinated carbocyclic analogues of 5-deoxypentofuranoses is described. The sequence involves an addition of PhSeCF₂TMS to carbohydrate-derived aldehydes followed by a radical cyclization, and provides a secure strategy for a future synthesis of pentofuranoses and nucleoside analogues.     

Nouvelle voie d'acces au diethylacetal de l'amino-2 cyano-3 formyl-5 pyrazine

An unequivocal two step synthesis of 2-amino-3-cyano-5-formylpyrazine diethylacetal, starting from dimethylaminoacrolein and O-tosylisonitrosomalononitrile, is described. This pyrazine is a key intermediate for the preparation of folic acid and various analogues.     

Synthesis and Properties of Some Spin Labeled Uridine and 2′-Deoxyuridine Analogues

The synthesis of the spin-labeled uridine and 2′-deoxyridine analogues RUGT 2 , DUGT 3 , l-RUGT 4 , and l-DUGT 5 is described. DUGT 3 showed some activity against the leukemia P388 cell line.     

Streptonigrin and related compounds IV. Precursors for the a-ring

The synthesis of streptonigrin or its tricyclic (ABC) analogues by the Friedlander condensation requires a 2-nitrobenzaldehyde with all the necessary functionalities. A number of alternative syntheses are examined. It is shown that oxidation of 8-amino-5,6-dimethoxy-2,2-pyridylquinoline leads to 8-amino-2,2-pyridylqunoline-5,6-dione instead of 6-methoxy-2,2-pyridylquinoline-5,8-dione. The synthesis of two useful precursors: 4-bromo-3-hydroxy-5,6-dimethoxy-2-nitrobenzaldehyde and 4-bromo-3-hydroxy-5-methoxy-2-nitrobenzaldehyde is described.     

Parallel approach for solution-phase synthesis of 2-quinoxalinol analogues and their inhibition of LPS-induced TNF-alpha release on mouse macrophages in vitro

A parallel solution-phase synthesis of 2-quinoxalinol analogues is described. The key step-simultaneous reductions of m-Ar(NO(2))(2) to m-Ar(NH(2))(2) was investigated extensively. We obtained preliminary pharmacological activity of those analogues for the inhibition of LPS-induced TNF-alpha release on mouse macrophage in vitro. Two compounds revealed inhibitory activity, with IC(50) values of 0.40 microM (7-amino-6-[(3-methoxypropyl)amino]-3-methyl-2-quinoxalinol) and 2.2 microM (7-amino-6-[(3-butoxypropyl)amino]-3-methyl-2-quinoxalinol), respectively.     

Synthesen neuer Phosphono-Analoga von Pantethein-derivaten

Syntheses of New Phosphono Analogues of Pantetheine Derivatives The phosphono analogues 5 and 13 of pantothenate 4′-(dibenzyl phosphate) and pantetheine 4′-(dibenzyl phosphate), respectively, are prepared as intermediates for the synthesis of a coenzyme-A phosphono analogue (Schemes 1 and 2). The synthesis of phosphono analogues 20 and 21 of oxapantetheine, which are structurally similar compounds to the phosphono analogue of pantetheine, is also described (Scheme 3).     

Synthesis and conformational analysis of new cyclobutane-fused nucleosides

[structure: see text]. A stereselective synthesis of 3-oxabicyclo[3.2.0]heptane nucleoside analogues, which were designed as conformational mimics of the anti-HIV agents 2',3'-didehydro-2',3'-dideoxythimidine (stavudine, d4T) and 2',3'-didehydro-2',3'-dideoxyadenosine (d4A), is described. The target compounds were prepared by condensation of a common intermediate bicyclic acetate, derived from a homochiral 2(5H)-furanone, with pyrimidine and purine bases under modified Vorbrüggen conditions. The conformational behavior of the synthesized nucleoside analogues was studied by NMR spectroscopy and X-ray crystallography.     

A new method for the synthesis of plurisubstituted pyrroles

A versatile method for the synthesis of pyrroles is described using an intramolecular [3+2] cycloaddition reaction. This method allows the expedient preparation of ‘plurisubstituted’ compounds in which functionality is incorporated by choice, using appropriate readily available starting materials. Polycyclic pyrrole derivatives as well as 2-aryl monocyclic analogues are described. Several families of compounds are synthesized by sequential transformations. The method is designed to allow the creation of libraries with increased diversity of functionality by combinatorial or parallel synthesis.     

Renin inhibitors. I. Synthesis and structure-activity relationships of transition-state inhibitors containing homostatine analogues at the scissile bond.

The synthesis and structure-activity relationships of transition-state renin inhibitors containing the homostatine analogues at the scissile bond are described. These inhibitors incorporate the amino acid side chains corresponding to positions 7-12 (P4-P2') of angiotensinogen. Ethyl, 2-hydroxyethyl and 3-hydroxypropyl groups at position 2 of the homostatine analogues (P1') are more effective for increasing potency than the isopropyl group. A combination of residues at P1, P3 and P4 is important for potency and this result suggests that S1, S3 and S4 form a huge hydrophobic core together in renin.     

An efficient synthesis of (Z)-α-fluorochalcones via the palladium-catalyzed cross-coupling reaction of (Z)-α-fluorocinnamoyl chloride with boronic acids

An efficient synthesis of α-fluorochalcones (1,3-diphenyl-2-fluoroprop-2-en-1-one) based on the Suzuki–Miyaura palladium-catalyzed cross-coupling reaction of arylboronic acids with α-fluorocinnamoyl chlorides in the presence of Cs₂CO₃ in toluene is described. This approach allows the synthesis of fluorinated analogues of functionalized natural chalcones.     

Synthesis of novel KDR kinase inhibitors through catalytic reductive cyclization of o-nitrobenzylcarbonyl compounds

An efficient synthesis of o-nitrobenzylcarbonyl compounds is demonstrated through the Swern-type oxidation of readily accessible phenethanol analogues. Reductive cyclization of o-nitrobenzylcarbonyl 3 using catalytic Raney nickel gives 1H-indol-2-yl-1H-quinoline 2 in 95% yield. Hydrolysis of 2 affords the KDR kinase inhibitor 1 in quantitative yield. The examination of the reductive cyclization reaction and optimization of conditions is described.     

Synthesis of 8-aryl-substituted coumarins based on ring-closing metathesis and Suzuki-Miyaura coupling: synthesis of a furyl coumarin natural product from Galipea panamensis

The synthesis of 7-methoxy-8-(4-methyl-3-furyl)-2H-chromen-2-one, a natural product with antileishmanial activity recently isolated from the plant Galipea panamensis, is described. The key step is a Suzuki-Miyaura coupling of a furan-3-boronic acid and an 8-halocoumarin, which is advantageously synthesized using a ring-closing metathesis reaction. Several non-natural analogues are also available along these lines.     

11-deoxyhomoprostacyclin analogues

A short synthesis of 11-deoxyhomoprostacyclin analogues 3 and 3 is described. The key step involves an organocuprate conjugate addition - enolate alkylation reaction.     

Synthesis of migration-resistant hydroxyethoxy analogues of lysophosphatidic acid

[reaction: see text] The susceptibility of lysophosphatidic acid (LPA) to intramolecular acyl migration impedes the determination of specific receptor activation by the sn-1 and sn-2 LPA regioisomers. An efficient enantioselective synthesis of hydroxyethoxy (HE)-substituted analogues of sn-1-acyl and 2-acyl LPA derivatives that possess palmitoyl and oleoyl chains is described. While the palmitoyl derivatives fail to activate calcium release in cells transfected with LPA(2) or LPA(3) G-protein-coupled receptors, the LPA(3) receptor is activated by both 1-HE and 2-HE oleoyl LPA analogues with a potency 10-fold lower than that of the parent oleoyl LPA.     

Sequential Electrophilic Trifluoromethanesulfanylation-Cyclization of Tryptamine Derivatives: Synthesis of C(3)-Trifluoromethanesulfanylated Hexahydropyrrolo[2,3-b]indoles

A practical and efficient synthesis of C(3)-trifluoromethanesulfanylated hexahydropyrrolo[2,3-b]indoles 5 from tryptamine derivatives was described. The features of this synthesis included electrophilic activation of C(3) of tryptamine derivatives with "CF(3)S(+)" and cascade ring cyclization by carbamate nucleophile attacking at C(2). Surprisingly, when Lewis acid (BF(3)·OEt(2)) was used as activator instead of proton acid (TsOH·H(2)O) for the electrophilic trifluoromethanesulfanylation of tryptamine derivatives, the uncyclized product 6 was formed preferentially. This sequential trifluoromethanesulfanylation-cyclization protocol was used to synthesize several pyrrolidinoindolinic alkaloid analogues. The cytotoxicity activities of these trifluoromethanesulfanylated alkaloid analogues were evaluated against three cancer cell lines (K562, HeLa, L929).     

Synthesis of a 3,4,5-trimethoxybenzoyl ester analogue of epigallocatechin-3-gallate (EGCG): a potential route to the natural product green tea catechin, EGCG

The synthesis of a trimethoxybenzoyl ester (D-ring) analogue of epigallocatechin-3-gallate (EGCG) is described. The versatile synthesis route can be used to synthesize A, B, and D ring analogues of EGCG and involves a key cyclization of the chalcone to the 3-flavene. This synthesis provides a possible route to the polyphenolic green tea natural product EGCG.     

Synthesis of indole alkaloid analogues: novel domino stereoselective electrophile addition--cyclizations of tryptophan-derived alpha-amino nitriles

The synthesis of new indole alkaloid analogues, containing a 1,2,4,5,10b,10c-hexahydropyrrolo[1',2',3':1,9a,9]imidazo[1,2-a]indole skeleton, via highly stereoselective novel domino cyclative halogenation or prenylation reactions of tryptophan-derived alpha-amino nitriles, is described.