The tert-butoxycarbonyl group is used to protect the amino...

The tert-butoxycarbonyl group is used to protect the amino group of amino acids during the Merrifield solid phase peptide synthesis procedure. The group is then removed by treatment with anhydrous acid. The mechanism of addition and removal is as follows: 1. The amino acid under basic conditions reacts with di-tert-butyl dicarbonate to give tetrahedral intermediate 1; 2. collapse of the tetrahedral intermediate gives the BOC-aa; 3. in the removal sequence, protonation from anhydrous acid gives protonated intermediate 1; 4. elimination gives alkene 2 and carboxyamino acid 2; 5. decarboxylation gives CO2 and the amino acid. di-tert-butyl dicarbonate Work out the above mechanism on a separate sheet of paper and then draw the structure of BOC-aa.

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00:01 Hi students let me explain you the question so in this question here this question it is about merrifield solid phase solid phase peptide synthesis so in merrifield solid field peptide synthesis here it is the procedure where the peptides are synthesized so synthesis of peptides or proteins so here what happens during the merrifield solid -face peptide synthesis here amino acids these amino acids are polymer supported amino acids polymer supported that is resinous polymer supported amina acid they react with peptides these are succeeding peptides succeeding peptides so they repeatedly these amina acids are along with the peptides, they repeatedly reacts with n protected amino acids.

01:08 So n protected amino acids means amino group protected amino acid.

01:12 So this repetition takes place until we'll get desired peptide or protein.

01:19 So how we'll get n protected amino acid? so usually for protecting a minor group of amino acid will use tertiary butoxic tertiary butoxy carbonyl group.

01:36 Corbinile group.

01:37 So during this particular process, so this particular tertiary butoxy carbonile group, it protects the amino group of amino acid.

01:48 So later it will be removed.

01:50 So by treatment with anhydrous acid.

01:54 So by treatment with anhydrous acid, okay? so the mechanism of addition as well as the removal.

02:02 Removal of tertiary butoxic carbonyl group how the tertiary butoxy carbonile group is attached how the tertiary butoxic carbonyl group will be removed so we have to see the mechanism here so the mechanism mechanism so this is the amino acid so amino group and amino group this is the simple amino acid so here amino group and corboxylic acid group so am i know group it first step it reacts with a di tertiary butyl dichorbinate so it undergoes reaction with di tertiary butyl di corbinator dicorporonator di territiary butile dicorbinator so here this particular reaction it occurs in basic conditions so this will be shifted here you will get partial positive charge the lone pair of electrons which are present on the nitrogen will come and attach here so it leads to the formation of tetrahedral intermediate the structure of the hetrahedral intermediate is this is the structure of tetrahedral intermediate this is c o2h here this is the amino group nitrogen will get partial positive charge then it it reacts with the carbon atom oxygen here oxygen is will be the tetrahedral intermediate structure okay then this tetrahedral this is tetrahedral intermediate structure so this tetrahedral intermediate it undergoes collapse it undergoes collapse so collapse means break down so it undergoes collapse so it undergoes collapse so how it undergoes collapse means this bond it will be shifted to here and this negative charge it will be shifted to here this point it will be shifted to here so it leads to the formation of butoxycorbonile intermediate butoxy corbynile intermediate so like this so this butoxy corbynile intermediate so this is butoxy corbinole intermediate so this is butoxy carbonyl butoxy carbonyl amino acid so like this that is n protected amino acid is formed so from this it is the removal process how the n this butoxy corbinile group will be removed so i already told you this particular protected group butoxy carbonyl group will removed from the unhydros acid so it go on reacts with unhydrous acid here what happens protonation reaction takes place that this addition of proton addition of proton so by addition of proton it leads to the formation of protonated derivative so how the addition of proton will take place this will be shifted to here and this will be shifted to here and this will be removed of so it leads to the protonated derivative.

05:50 So the structure of protonated derivative, oh h, n, h.

06:04 This is the r group, c -o -2h...

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