K. Laxma Reddy

Solid-phase synthesis of new pyrrolobenzodiazepine-chalcone conjugates: DNA-binding affinity and anticancer activity.

A new class of C8-linked pyrrolo[2,1-c][1,4]benzodiazepine-chalcone conjugates have been prepared by employing a solid-phase synthetic protocol. In this strategy an intramolecular aza-Wittig reductive cyclization approach has been utilized. Interestingly, some of these molecules have shown enhanced DNA-binding affinity and promising anticancer activity on a large number of human cancer cell lines.

An expeditious approach for the synthesis of β-hydroxy aryl α-amino acids present in vancomycin

Stereoselective synthesis of the β-hydroxyaryl amino acids which constitute C and E rings of vancomycin is described making use of benzylic oxidation and asymmetric dihydroxylation as the key steps.

Synthetic studies towards glycopeptide antibiotics: synthesis of the 16-membered cyclic tripeptide (DOEG ring) system of teicoplanin

The synthesis of the 16-membered cyclic DOEG ring system of teicoplanin, which forms the binding pocket for the carboxylate region of terminal D-Ala-D-Ala of the bacterial cell wall via macroetherification of linear tripeptide 20 is described.

STUDIES DIRECTED TOWARDS THE TOTAL SYNTHESIS OF VANCOMYCIN : FORMATION OF BIPHENYL ETHER BY MACROCYCLISATION

A simple methodology for the construction of D-O-E diphenyl ether 16-membered ring system present in Vancomycin by intramolecular dispacement of fluorine by phenoxide reaction is described.

Ortho-nitro-promoted Ullmann ether synthesis: application in the syntheses of K-13 and the isodityrosine unit of vancomycin

A nitro group in the ortho-position of the aryl halide component facilitates Ullmann ether synthesis for the syntheses of all isodityrosine units present in wide variety of natural products, first time, on the basis of a common strategy.

Efficient solid-phase synthesis of DNA-interactive pyrrolo[2,1-c][1,4]benzodiazepine antitumour antibiotics

The solid-phase synthesis of DNA-interactive pyrrolo[2,1-c][1,4]benzodiazepine (PBD) imines and biologically important pyrrolo[2,1-c][1,4]benzodiazepine-5,11-diones on Wang resin using a reduction/cyclization procedure is reported.

Efficient reduction of aromatic nitro/azido groups on solid support employing indium: synthesis of pyrrolo[2,1-c][1,4]benzodiazepine-5,11-diones

Abstract An efficient method for the reduction of aromatic nitro and azido compounds on solid support using indium/NH 4 Cl is described. This solid-phase reduction technique has been applied to the synthesis of pyrrolo[2,1- c ][1,4]benzodiazepine-5,11-diones.

A concise route to biaryls : formal synthesis of biaryl diamino diacid (AB segment) of vancomycin

An efficient approach to the AB segment of vancomycin involving triphenylphosphine-catalysed coupling of the substituted aryl lithio compound (13) with palladium complex (14) of aromatic Schiff base derived from 3,5-dimethoxybenzaldehyde is described.

Studies directed towards the synthesis of immunosuppressive agent FK-506: Construction of the tricarbonyl moiety

Abstract Alkylation of a suitably functionalised dithiane precursor with L-N-(-haloacetyl)pipecolic acid methyl ester, followed by oxidation of the active methylene group provided an easy route to 1,2,3-tricarbonyl functionality of FK-506.

ESR and other spectral studies on copper(II) complexes with 2,3-disubstituted quinazoline-(3H)-4-ones

Abstract A number of copper(II) complexes of some tridentate ONO donors and bidentate OO and ON donors in the form of 2,3-disubstituted quinazolin-(3H)-4-ones have been synthesized and characterized based on analytical, conductivity, magnetic, IR, electronic and ESR spectral data. The reaction between copper(II) acetate and tridentate ONO donor ligands such as 2-(R)-3-(X)-substituted quinazoline-(3H)-4-ones, where R = methyl/phenyl and X = 2′-hydroxyphenylamino (MHBQ/PHBQ), yielded neutral complexes of the type Cu(ONO) 2 . The bidentate OO or ON donor ligands like 2-(R)-3-(X)-substituted quinazoline-(3H)-4-ones, where R = methyl/phenyl and X = carboxymethyl (MCMQ/PCMQ), furylamino (MFQ/PFQ), acetamino (MAQ/PAQ), uramino (MUQ/PUQ) and thiouramino (MTUQ/PTUQ), yielded neutral complexes of the type Cu(OO) 2 or Cu(ON) 2 (CH 3 COO) 2 . The IR spectral data of the metal complexes indicate that the ligands like MHBQ and PHBQ act as uninegative tridentate, MCMQ and PCMQ act as uninegative bidentate and MFQ, PFQ, MAQ, PAQ, MUQ, PUQ, MTUQ and PTUQ act as neutral bidentate ligands. The reflectance spectral studies of these complexes indicate that they contain square-planar or tetragonal geometry around copper(II).