Synthesis and biological evaluation of 1H-pyrrolo[2,3-d]pyrimidine-1,2,3-triazole derivatives as novel anti-tubercular agents.

A series of novel 1H-pyrrolo[2,3-d]pyrimidine-1,2,3-triazole derivatives have been synthesized in good to excellent yields. Through the copper-catalyzed azide-alkyne cycloaddition via reaction of 7-(prop-2-ynyl)-7H-pyrrolo[2,3-d]pyrimidine and aryl, heteroaryl and alkyl azides in the presence of CuSO·5HO and sodium ascorbate. These compounds were evaluated for their in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv strain.

Synthetic studies toward the marine metabolite prorocentin-4: synthesis of the C1-C23 fragment.

A synthetic study of the construction of the C1-C23 fragment of prorocentin-4, a novel linear polyketide, is described. The synthetic highlights include the acid catalyzed epoxide opening, Gilman reaction, Pd(OH)2 catalyzed transformation of a primary propargylic alcohol into an aldehyde, Oxa-Michael cyclization, and Horner-Wadsworth-Emmons (HWE) olefination reaction as key steps.

Synthesis and biological evaluation of 1-amino isochromans from 2-bromoethyl benzaldehyde and amines in acid medium.

We have developed a facile and efficient synthetic route to substituted isochromans for the first time by reacting 2-(2-bromoethyl)benzaldehyde with a variety of aryl, heteroaryl amines in AcOH. The reaction is catalyst/additive free and takes place at reflux conditions with short reaction time to furnish products in good to excellent yields. All the compounds have been characterized by spectral techniques such as IR, H NMR and Mass etc.

First stereoselective total synthesis of brevipolide M.

The first stereoselective total synthesis of a cytotoxic brevipolide M, which shares a pyrone framework bearing a tetrahydrofuran moiety and a cinnamate group with the readily available (-)-DET, is described. The key steps involved in the synthesis are the epoxide-opening, Brown's allylation, and the RCM reaction to install an α,β-unsaturated lactone ring and the inversion of the C-6' stereogenic hydroxyl group using the Mitsunobu reaction.

A diastereoselective synthesis of tetrahydro- and dihydro-pyrido[2,3-c]coumarin derivatives via a one-pot three-component Povarov reaction catalyzed by bismuth(III) chloride.

A diastereoselective synthesis of tetrahydro- and dihydro-pyrido[2,3-c]coumarin derivatives has been achieved via a one-pot three-component aza-Diels-Alder reaction of aromatic aldehydes, 3-aminocoumarin and dienophiles catalyzed by BiCl. NOE studies proved that exo-isomers were obtained in all cases with high selectivity. The reaction proceeded at room temperature providing good yields of products as well as applicability on a wide range of substrates.

Total Synthesis of Anticancer Agent EBC-23.

Total synthesis of spiroketal EBC-23 has been described by two divergent approaches from three simple building blocks. Gold-catalyzed cycloisomerization of alkynol and acid-mediated spirocyclization of diketalketone were successfully utilized to effect spiroketal formation. A Cu(I)-P(Cy)3-catalyzed protocol for the highly regio- and stereocontrolled hydroboration of internal propargylic alcohol was effectively applied toward the β-hydroxy ketone via vinylboronates.

The first total synthesis of (+)-goniothalesacetate and syntheses of (+)-altholactone, (+)-gonioheptolide A, and (-)-goniofupyrone by an asymmetric acetate aldol approach.

The first stereoselective total synthesis of (+)-goniothalesacetate and total synthesis of several bioactive styryl lactones, (+)-altholactone, (+)-gonioheptolide A, and (-)-goniofupyrone have been achieved from an advanced intermediate, which can be derived from L-(+)-DET.

Synthesis of the C1-C25 southern domain of spirastrellolides B and F.

Synthesis of the C1-C25 ABC spiroketal ring system of spirastrellolides B and F has been executed. The synthetic strategy relied on radical cyclization, HWE olefination, (BDP)CuH conjugate reduction and spiro acetalization reactions.

Palladium hydroxide catalyzed isomerization of primary allylic alcohols to aldehydes: application to the formal synthesis of (-)-brevisamide.

The Pd-catalyzed isomerization of primary allylic alcohols into the corresponding saturated aldehydes has been achieved at room temperature for the first time in good to excellent yields under mild conditions. The functional group compatibility in this reaction is studied, and this new methodology has been successfully applied in the synthesis of a C5-C13 tetrahydropyran ring system of (-)-brevisamide in seven steps.

Synthesis of (3R,5R)-harzialactone A and its (3R,5S)-isomer.

The total synthesis of (3R,5R)-harzialactone A (1) and its (3R,5S)-isomer (2) is described. Epoxide opening with thioacetal and diastereoselective reductions are used as key reactions.

Cerium(III) chloride promoted highly regioselective ring opening of epoxides and aziridines using NaN(3) in acetonitrile: a facile synthesis of 1,2-azidoalcohols and 1,2-azidoamines.

A convenient and efficient synthesis of 1,2-azidoalcohols and 1,2-azidoamines has been achieved by ring opening of epoxides and aziridines using cerium(III) chloride and sodium azide in acetonitrile. The reaction is highly regioselective and afforded the corresponding products in good to excellent yields under mild and neutral reaction conditions. The method is very rapid and equally compatible for both epoxides and aziridines.