Chemistry Reference
In-Depth Information
O
O
O
O
O
O
O
O
O
O
N
Me
NH
NH
NH
NH
NH
H
N
N
Pip
Aib
Pip
Aib
Aib
Leu
β
-Ala
Gly
Acc
(A)
(B)
O
N
O
O
O
O
O
O
O
N
N
NH
NH
NH
NH
NH
NH
NH
Me
N
3M-Pro
Aib
Aib
Pip
Aib
Gly
Leu
Iva
X
(F)
(C)
(D)
(E)
Figure 10.2
Structures of efrapeptin D (4) (amino acidwith underline shows variable residues)
10.2.1.3
Pyrostatins
Imada et al. reported the isolation of pyrostatins A and B from culture broth of strain
Streptomyces sp. SA-3501 isolated from a marine sediment [19,20]. The structures were
determined as 2-iminopyrrolidine carboxylic acid derivatives 7-8. These compounds showed
specific inhibitory activity against N-acetylglucosaminidase but no antimicrobial activity.
Recently, Castellanos et al. [21] reported the isolation of a compound with same structure as
pyrostatin B (8) fromCaribbeanmarine spongeCliona tenuis; however, the spectral datawere
not identical with those published for pyrostatin B. Total synthesis of the compound with the
structure of 8 was achieved to demonstrate that the synthesized 8 was identical with the
compound isolated by Castellanos but not with pyrostatin B previously isolated by Imada
et al. Further searching of the literature lead to the conclusion that the actual NMR data
reported for pyrostatin B matched those of ectoine (9) [22,23], another amidine alkaloid
isolated from extremely halophilic species of the bacterial genus Ectothiorhodospira [24].
Isolations of noformycin (10) [25] with antiviral activity [26] and an inhibitory effect
towards inducible-nitric oxide synthase [27] and other iminopyrroglutamic acid derivatives
11-13 have also been reported. The latter were inhibitors towards Erwinia amylovora,a
bacterium responsible for the fire light disease of apple and pear trees [28] (Figure 10.3).
Table 10.1
Amino acid residues in efrapeptins and neoefrapeptins
neoefra-
peptins
efrapeptins
(A)
(B)
(C)
(D)
(E)
(F)
(A)
(B)
(C)
(D)
(E)
(F)
C(
)
Aib Aib Aib Pip Gly Aib A (
)
Iva Aib Acc Pip
Gly Iva
3
6
D(
)
Aib Aib Aib Pip Gly Iva B
Iva Iva Acc Pip
Gly Iva
4
E(
)
Iva Aib Aib Pip Gly Iva C
Iva Aib Acc Pip
Gly Iva
5
F
Aib Aib Aib Pip Ala
Iva
F
Iva Aib Acc 3M-Pro Gly Iva
G
Iva Aib Alb Pip Ala
Iva
I
Iva Iva Acc 3M-Pro Gly Iva
