CHM 2123 Lecture Notes - Lecture 4: Glucoside, Benzene, Triethylamine
17 Dec 2017
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Document Summary
Experiment 4: benzylidene acetals as a protecting group. Oligosaccharides and glycoconjugates: shape of cells and organs. Structure and function via dna, rna, atp and glycoproteins. Present on cell surfaces for cell recognition and signaling (by glycans) Glycans: targets for carb-biding proteins and changes it to signal disease progression. Tumors produce unique carb sequences on their surfaces relative to healthy cells. Good way for diagnosis, vaccination and therapeutic remedies. Dissolving in aqueous base: keto-enol tautomerization leading to isomerization. Acetals protect alcohols, aldehydes, and ketones from being reduced, undergoing nucleophilic additions, or reacting with bases. Acetals are stable to nu because they do not have a good leaving group for an sn2. They are stable to bases because they do not have a remove-able proton. Aldehydes and ketones will react (reversibly) with alcohols + acid cat. to give acetals. Acetal: carbon bound to to 2 alkoxy groups (or) Hemiacetal: carbon bound to one alkoxy, and one hydroxyl.
