Protective strategies, Influence

Emergency response has a significant influence on a company s fire protection strategy. The question is "to fight, or not to fight" fires at a facility. Emergency response is one of the last layers of protection available to a facility (CCPS, 2001a). 

Replacement of methionine by norleucine is a common way to eliminate unwanted side reactions (oxidation and alkylation) that can be observed especially when using a Boc protection strategy. Owing to the similarity of Met and Nle side chains, the exchange usually has no significant influence on the structure of peptides. 

This revised strategy demonstrates that a simple change in hydroxyl protecting groups can markedly influence reactivity and selectivity. While formation of the Wittig salt 51 could now be achieved at atmospheric pressure, its coupling with aldehyde 45 only proceeded in moderate yield and selectivity. 

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