L. Rajender Reddy

A Mild and Efficient Method for Tetrahydropyranylation/Depyranylation of Alcohols and Phenols Under Neutral Conditions

Abstract Alcohols and phenols are tetrahydropyranylated rapidly in high yields in the presence of lithium bromide and dichloromethane at room temperature. Deprotection of these THP ethers can also be effected readily by mere change of the solvent to methanol and refluxing with excess lithium bromide. Due to neutral reaction conditions employed, the method is also compatible with compounds having acid sensitive functional groups.

AN EFFICIENT BIOMIMETIC CLEAVAGE OF GEM-DIACETATES TO ALDEHYDES BY β-CYCLODEXTRIN UNDER NEUTRAL CONDITIONS IN AQUEOUS MEDIUM*

ABSTRACT The cleavage of gem-diacetates to aldehydes, a widely used protecting group in organic synthesis, has been achieved for the first time under neutral conditions in aqueous medium using β-cyclodextrin as catalyst. The main advantage of the present methodology is that it can be used with compounds having a variety of functional groups since the cleavage is carriedout under neutral conditions in aqueous medium. *IICT Communication No. 4655.

Selective deprotection of tetrahydropyranyl ethers catalysed by β-cyclodextrin in water

The hydrolysis of tetrahydropyranyl ethers to alcohols catalysed by β-cyclodextrin proceeds in water under neutral conditions.

Dynamic kinetic asymmetric synthesis of β-aminoalcohols from racemic epoxides in cyclodextrin complexes under solid state conditions

It has been shown for the first time that enantiopure β-aminoalcohols can be prepared from racemic epoxides by dynamic kinetic resolution involving enantio-differentiating racemisation in cyclodextrin complexes under solid state conditions.

The First Selective 2,6-Per -O-Cinnamoylation Of β-Cyclodextrin1

Abstract 2,6-Per-O-cinnamoylated β-cyclodextrin has been synthesised for the first time by the reaction of cinnamoyl esters with β- cyclodextrin in presence of sodium hypochlorite in water.

A NOVEL AND EFFICIENT BIOMIMETIC HYDROLYSIS OF OXIRANES TO 1,2-DIOLS CATALYSED BY β-CYCLODEXTRIN IN WATER UNDER NEUTRAL CONDITIONS

The 1 ,2-diol functionality has great sigmficance in pharmaceutical and industrial chemistry’ due to its utility in the synthesis of bacteriostatic2 and antifogging agents: P-blockers? perfumes5 and in the polymer industry: However, the facile synthesis of these commercially important 1 ,2-diols consists of the ring opening of the easily accessible epoxides under acidic conditions at room temperature or at high temperatures under basic conditions.’ Since these harsh experimental conditions involving either acid or base are not suitable for the epoxides bearing labile substituents, there is need to develop milder methods. Cyclodextrins (CDs) which are cyclic oligosaccharides, exert microenvironmental effect leading to selective reactions. They catalyze reactions by supramolecular catalysis through non-covalent bonding as in enzymes. These biomimetic reactions can be carried out efficiently in water.8 This biomimetic approach of chemical reactions involving supramolecular catalysis has several advantages over chemical methodologies since these reactions can be carried out under mild and neutral conditions in water. Hence, in our effort to develop biomimetic approaches of chemical reactions involving cyclodextrins? the synthesis of 1 ,2-diols from epoxides (derived from cyclic and terminal alkenes) catalyzed by cyclodextrins (a and P) in water under neutral conditions was developed.

A new fluorescent chemosensor: synthesis and molecular recognition by sulfamidopyrrolidinylidene modified β-cyclodextrin

Mono[6-deoxy-6-(1-methyl-2-pyrrolidinylidenesulfamido)-β-cyclodextrin synthesised as new artificial receptor has shown molecular recognition with remarkable sensitivity to various organic compounds with variation of fluorescence upon guest binding.