Synthetic study of leonurine and its analogues
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Leonurine 1, isolated from Leonurus sibiricus and a .
Leonurus artemisia, was found to have uterotonic effect.
Ther~fore leonurine 2 and some of its analogues were
synthesized for pharmaceutical study.
An efficient, two-step synthesis of leonurine 3 from
syringic acid 1 and 4-amino-l-butanol 16 is described. The amino alcohol ~ was treated with S-benzyl-iso-
thiourea hydrochloride 65 affording 4-guanidino-l-butanol
hydrochloride l. Direct condensation of syringic acid 1
and 2 in the presence of DCe in HMPT or 1:1 HMPT-ether
gave in high yield of leonurine 3 which was identical in
all respect with the natural leonurine isolated from
This direct condensation of carboxylic acid' and alcohol
was extended to the synthesis of the following leonurine
analogues - twelve guanidinoalkyl esters, twenty-two
aminoalkyl esters, two imidazoylalkyl esters. and three
The effect of~phenolic group in the carboxylic acids
on the DeC promoted ester condensatio~ in HMPT as solvent
Synthesis of amino esters was achieved either by direct
condensation ofo..carboxylic acid wi th r~spec.tlv.e.;" protonated .~
amino alcohols in the presence of DCC, or by reaction of
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carboxylic acid and chloroalkylamine in triethylamine. The yield of aminoalkyl esters synthesized by these two methods
The mass spectra of leonurine 3 and its guanidino
analogues were analysed.
School:The University of Hong Kong
School Location:China - Hong Kong SAR
Source Type:Master's Thesis
Date of Publication:01/01/1979