D. Subhas Bose

New approaches to pyrrolo[2,1-c][1,4]benzodiazepines: synthesis, DNA-binding and cytotoxicity of DC-81

Two routes to the naturally occurring DNA-binding antitumour antibiotic DC-81 are described, one of which involves a novel cyclization process based on acid resin. The second route involves the synthesis of a new compound, 6-nitrovanillic acid, a key A-ring component of many naturally occurring PBDs. These routes have provided a sufficient quantity of DC-81 to allow complete characterization and evaluation in DNA-binding and in vitro cytotoxicity studies.

Effect of linker length on DNA-binding affinity, cross-linking efficiency and cytotoxicity of C8-linked pyrrolobenzodiazepine dimers

An efficient synthesis of a homologous series of C8-linked pyrrolobenzodiazepine dimers is reported; compounds with an odd number of methylenes (n= 3 or 5) in the linker show a higher affinity for DNA, enhanced cross-linking efficiency, and are more cytotoxic compared with compounds with either n= 4 or 6.

Diversity-Oriented Synthesis of Quinolines via Friedlander Annulation Reaction under Mild Catalytic Conditions

An efficient and practical method has been manifested for the diversity-oriented synthesis of quinolines via Friedländer annulation reaction for the generation of a wide range of structurally interesting and pharmacologically significant compounds by using ceric ammonium nitrate as a catalyst (10 mol %) at ambient temperature in 45 min. A variety of functional groups are introduced at various positions of the quinoline moiety, and further the diversity of the core skeleton was expanded at R(1) and R(2) positions by the synthesis of various hybrids. Initial screening of the compounds for cytotoxicity against a series of cancer cell lines showed promising results.

Water-tolerant and Reusable Catalyst for the One-pot Synthesis of Dihydropyrimidin-2(1H)-ones under Solvent-free Conditions

An efficient and eco-friendly synthesis of 3,4-dihydropyrimidin-2(1H)-ones, has been achieved by a three-component condensation reaction of an aldehyde, β-ketoester and urea, in the presence of K 5 CoW 12 O 40 .3H 2 O (0.01 equiv. or 1.0 mol %) as catalyst under solvent-free conditions. The catalyst exhibited remarkable reusable activity. The scope of this method is utilized for the synthesis of mitotic kinesin EG5 inhibitor monastrol.

Boron trifluoride promoted cleavage of benzyl carbamates

Abstract A new efficient method for the cleavage of benzyl carbamates (CBZ protective groups) is described that involves a hard acid (BF3.OEt2) - soft nucleophile (EtSH) system. Unlike other available methods, this combination avoids the reduction of olefins, acetylenes, imines, halides and nitro groups, or the possibility of carboxylic ester hydrolysis.

Sn(III)Cl2-induced regiospecific opening of the 1,3-benzodioxole ring system: A route to the novel DNA-interactive, ligand) iso-DC-81

A novel tin-catalysed regiospecific cleavage of a 1,3-benzodioxole ring system is reported that has been applied to the synthesis of a uniquely-substituted DNA-binding pyrrolo[2,1-c][1,4]benzodiazepine antitumour agent, iso-DC-81(4a).