Date of Award

12-1-1979

Degree Type

Thesis

University or Center

Atlanta University (AU)

Degree Name

M.S.

Department

Chemistry

First Advisor

Professor Malcom B. Polk

Abstract

The attempted synthesis of p-nitrobenzyloxycarbonyl-L
phenylalanyl-N-carbobenzoxy--L-histidyl-L- leucine methyl ester,
an intermediate in the synthesis of p-nitrobenzyloxycarbonyl-L
phenylalanyl-N-carbobenzoxy-L-histidyl-L-leucine_4_hydroxy3-
methoxybenzyl ester is described. This tripeptide intermediate
will be important in the development of a tripeptide fluorogenic
substrate for angiotensin-converting enzyme because of its fluore
scent probe.
Analyses indicate that L-phenylalanyl-N-carbobenzoxy-L
histidyl-L-leucine methyl ester hydrochloride tetrahydrate was
obtained as a result of cleavage of the p-nitrobenzyloxycarhonyl
group from p-nitrobenzyloxycarbonyl-L-phenylalanyl-N-carbohenzoxy
L-histidyl-L-leucinemethyl ester.
We attempted to prepare the tripeptide intermediate by the
use of the stepwise approach starting from the carboxyl terminal
end and adding one N-protected acid after the other. Dicarbobenzoxy
L—histidine and L-leucine methyl ester were coupled by the dicyclo—
hexylcarbodiimide method to form dicarbobenzoxy-L-histidyl-L
leucine methyl ester. The latter was treated with hydrobromic acid
in dioxane and the crude dihydrobromide, after neutralization, was
reacted with p-nitrobenzyloxycarbonyl-L-phenylalanjne to form
p_nitrobenzyloxycarbonyl-L-phenylalany1-N-carbobenzoxy-L-histidy1-
L-leucine methyl ester.

Included in

Chemistry Commons

Share

COinS