Protecting group acetyl

After the N acetyl protecting group has served its purpose it may be removed by hydrolysis liberating the ammo group... 

SAMSA-fluorescein, 5- [2(and 3)-5-(acetylmercapto)-succinoyl]amino fluorescein, is a fluorescent probe containing a protected sulfhydryl group. In its protected state, the compound is unre-active. The acetyl-protecting group can be removed by treatment with dilute NaOH at pH 10.0 (Figure 9.9). The resulting free sulfhydryl derivative can be used to label thiol-reactive crosslinkers or to couple with sulfhydryl residues on proteins and other molecules. After activating... 

The resolution was then based on the enzymatic propanolysis of this derivative in dioxane as solvent. Lip Novozyme 435 selectively cleaves the L-form of the oxazolone producing an L-enriched (81-87% ee) 2-acetamido-3-(heteroaryl)propionic acid propyl ester, the dynamic aspect of the process being based on the continual racemization of the residual oxazolone. The propyl group was then removed with alkali and a second selective enzymatic step to remove the acetyl protecting group with Fluka Acylase 1 produced the L-amino acid at better than 99% ee (Scheme 13). 

Oligonucleotides containing amine groups introduced by enzymatic or chemical means may be modified with SATA (Chapter 1, Section 4.1) to produce protected sulfhydryl derivatives. The NHS ester end of SATA reacts with a primary amine to form a stable amide bond. After modification, the acetyl protecting group can be removed as needed by treatment with hydroxylamine under mildly alkaline conditions (Fig. 401). The result is terminal sulfhydryl groups that can be used for subsequent labeling with thiol-reactive probes or activated-enzyme derivatives (Kumar and Malhotra, 1992). 

In both, cases for sugar moieties the acetyl protective groups are very useful for stabilizing the O-glycosidic linkage against TFA or hydrogen fluoride... 

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