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Specialty Chemistry Forums => Biochemistry and Chemical Biology Forum => Topic started by: danyrs on September 24, 2016, 02:01:07 PM

Title: why is phenylalanine ring deactivated?
Post by: danyrs on September 24, 2016, 02:01:07 PM

in the xanthoproteic test, my book says it only reacts with 2 of the 3 aromatic aminoacids, my question is why?, why is deactivated the ring?, bc i understand that an alkyl group (the closest CH2 the ring has) is an activating group. Thanks.

Title: Re: why is phenylalanine ring deactivated?
Post by: AWK on September 25, 2016, 12:58:00 AM

This is a problem of reactivity. Phenyl ring in Phe is not deactivated, it is insufficiently activated.
Phenol is nitrated by pure HNO₃ (sometimes even diluted), where us benzene or toluene - by a nitrating mixture (conc. HNO₃ + conc. H₂SO₄)