Their starting proteins hydroxylated

In the production of acid hydrolysates of proteins using hydrochloric acid, the residual sterols and their esters occurring in the starting materials yield small amounts of 3-chloro derivatives by replacement of the C-3 hydroxyl group with chlorine. Possible intermediates in the formation of 3-chlorosterok maybe 3,5-dienes derived from sterols (Figure 3.91). 

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