Croatica Chemica Acta, Vol. 46 No. 2, 1974.
Izvorni znanstveni članak
Glycosyl Esters of Amino Acids. VI. Synthesis and Properties of Unprotected Glucosyl and Glucuronic Esters of Glycine and Alanine
D. Keglević
; Tracer Laboratory, Institute »Ruder Boskovic«, 41000 Zagreb, Croatia, Yugoslavia
Dj. Ljevaković
; Tracer Laboratory, Institute »Ruder Boskovic«, 41000 Zagreb, Croatia, Yugoslavia
S. Valenteković
; Tracer Laboratory, Institute »Ruder Boskovic«, 41000 Zagreb, Croatia, Yugoslavia
Sažetak
Treatment of 1-0-(N-tert-butyloxycarbonyl-glycyl- and -L-
alanyl)-~-n-glucopyranose s with trifluoroacetic acid at - 10 °C,
led to a clean removal of the BOC-protecting group without
affecting the C-1 ester linkage. The corresponding unprotected
glucosyl esters I and II were isolated as trifluoroacetate salts
and characterized by phyisical methods and by conversion into the
known N-acetyl derivatives III and IV. In the gluc;uronic ester
series, conditions for selective deprotection of the sugar moiety were
examined with benzyl 2,3,4-tri-O-benzyl-1-0-(N-acetyl-L-alanyland
-1-0-(N -tert-butyloxycarbonyl-L-alanyl)-o-glucopyranuronates
(V and VI). Catalytic hydrogenation of the ~ anomers of V
and VI gave the corresponding 1-0-acylaminoacyl-~-n-glucopyranuronic
acids VII and VIII; for characterization purposes, VIII
was converted into methyl 2,3,4-tri-0-acetyl-1-0-(N-tert-butyloxycarbonyl-
L-alanyl)-~-n-glucopyranuronate (IX-~), prepared
also by an alternative route. Complete deprotection of VIII afforded
1-0-(L-alanyl)-~-o-glucopyranuronic acid trifluoroacetate salt
(X) which was also obtained by catalytic hydrogenation of
benzyl 2,3,4-tri-O-benzyl-1-0-(N -benzyloxycarbonyl-L-alanyl)-~-D-
glucopyranuronate (XI) in the presence of trifluoroacetic acid.
Selective deprotection of the hydroxyl and carboxyl functions in
the a anomer of VI by catalytic hydrogenation, led to a concomitant
1-+ 2 acyl migration; the rearrangement product was
characterized as methyl l ,3,4-tri-O-acetyl-2-0-(N-tert-butyloxycarbonyl-
L-alanyl)-o-glucopyranuronaie (XII), highly enriched in
the a anomer.
Ključne riječi
Hrčak ID:
196826
URI
Datum izdavanja:
1.11.1974.
Posjeta: 520 *