Gowravaram Sabitha

A novel TMSI-mediated synthesis of Hantzsch 1,4-dihydropyridines at ambient temperature ☆

The synthesis of various substituted Hantzsch 1,4-dihydropyridines has been achieved using the classical Hantzsch procedure and modified Hantzsch conditions for the first time at room temperature in the presence of iodotrimethylsilane (TMSI) generated in situ in CH3CN, in excellent yields.

Vanadium(III) chloride catalyzed Biginelli condensation: solution phase library generation of dihydropyrimidin-(2H)-ones

The three component condensation of an aldehyde, a β-keto ester and urea (thiourea) in the presence of a catalytic amount of VCl 3 is disclosed for the solution phase synthesis of dihydropyrimidinones. The ease of synthesis and work-up allowed the parallel synthesis of a 48-membered library of dihydropyrimidinones quickly and efficiently in good yields.

Highly regioselective ring opening of epoxides and aziridines using cerium(III) chloride

A wide variety of epoxides and aziridines were converted to the corresponding β-halohydrins and β-haloamines using cerium(III) chloride and the cerium(III) chloride/NaI system in acetonitrile. The reactions were highly regioselective and efficient with excellent yields under mild and neutral reaction conditions.

Stereoselective total synthesis of (+)-artemisinin ☆ ☆☆

The total synthesis of the novel antimalarial drug, a sesquiterpene endoperoxide, (+)-artemisinin is described. The approach is flexible and stereoselective. The use of an intermolecular radical reaction on an intermediate iodolactone and a Wittig reaction on a ketone were employed for the synthesis.

Addition of pyrroles to electron deficient olefins employing InCl3

Pyrroles undergo conjugate addition with electron deficient olefins in the presence of a catalytic amount of indium trichloride at ambient temperature to afford the corresponding Michael adducts in excellent yields with high selectivity without polymerisation.

Cerium(III) Chloride–Catalyzed One-Pot Synthesis of Tetrahydrobenzo[b]pyrans

Abstract Efficient one-pot synthesis of 4H-benzo[b]pyrans via a three-component cyclocondensation of aryl aldehydes, malononitrile, and dimedone has been reported using CeCl3·7H2O as catalyst.

InCl3-catalyzed regioselective opening of aziridines with heteroaromatics

A variety of N-tosylaziridines undergo ring opening with pyrrole, furan, thiophene and indole in the presence of a catalytic amount of indium trichloride at ambient temperature to afford the corresponding β-aminoheterocycles in good yields with high regioselectivity.

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.

Bismuth(III) chloride-catalyzed intramolecular hetero-Diels–Alder reactions: a novel synthesis of hexahydrodibenzo[b,h][1,6]naphthyridines☆

BiCl3 efficiently catalyzed the intramolecular hetero-Diels–Alder reactions of aldimines generated in situ from aromatic amines and the N-allyl derivative of o-aminobenzaldehyde in refluxing acetonitrile to afford a novel class of hexahydrodibenzo[b,h][1,6]naphthyridine derivatives. The products are isolated as mixtures of trans and cis diastereoisomers in a 1:1 ratio, in good to excellent yields.

Deprotection of sulfonamides using iodotrimethylsilane

The deprotection of sulfonamides is achieved under neutral conditions by reaction with iodotrimethylsilane in acetonitrile at reflux.