lkylation reagents to search for ether groups leading
to better chromatographic separation (Table 1). However,
these studies showed that the benzyl group was
the best (Fig. 2). Namely, only GB (3) and GC (4) reacted
with benzyl bromide, while neither GA (2) nor
GJ (5) were benzylated within the 2 h reaction condition.
Furthermore, the Rf values of both BnGB (6)
and BnGC (7) were distinct from the unreacted GA
(2) and GJ (5). Other etherifications turned out to be
not suitable for the following reasons: (i) Allyl bromide
and cinnamyl bromide lead to partial etherification of
GA (2), products of which could not be separated from
the corresponding GB derivatives; (ii) p-Methoxybenzyl
chloride provided desired products from GB (3) andGC
(4) while GA (2) and GJ (5) remained intact. However,
the Rf value of the GC derivative (Table 1, entry 3) was
identical with GA (2).