Access Type

Open Access Dissertation

Date of Award

1-1-2010

Degree Type

Dissertation

Degree Name

Ph.D.

Department

Chemistry

First Advisor

Peter R. Andreana

Abstract

Microwave-influenced diversity-oriented synthesis of biologically relevant small and natural-product-like molecules via multicomponent coupling reactions (MCCRs) have been investigated. Cheap, readily available starting materials in conjunction of microwave irradiation and employment of environmentally benign solvent (e.g. water) provided a common platform that allowed to access a wide array of structurally and skeletally diverse molecules. The investigation allowed us to establish a new paradigm of diversity-activity relationships (DARs) by tuning reacting components of the MCCRs and proved that in contrary to the conventional use of microwave as a rate accelerating tool, it can be used to influence reactivity of molecules. The method was also extended to develop new protecting groups (PGs, PDMAB, PMNPAB) that can be useful in carbohydrate as well as other areas of synthetic organic chemistry. Additionally, the new p-N,N-diemethylaminobenzyl (PDMAB) PG was employed to develop an alkoxide-based neutral glycosylation and further extended to study entirely neutral glycosylation via oxocarbenium ion.

We also investigated the total synthesis of the repeating tetrasaccharide unit of zwitterionic polysaccharide PS A1 using different strategies. PS A1 is known to modulate T-cell response via MHC-II pathway and shown to prevent tumor growth. The synthesis is quite challenging and we have been able to construct the trisaccharide unit of the repeating tetrasaccharide unit of PS A1.

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