Guadinomine

1. Discovery, producing organism and structures1,2)
Guadinomines were found from the culture broth of the actinomycete strain K01-0509 as inhibitors of Type III secretion system (TTSS), which is a common virulence system present in many
gram-negative bacteria. Guadinomines A-D consist of a carbamoylated cyclic guanidinyl moiety,an alkyl chain moiety and an L-Ala-L-Val moiety in common. While guadinomic acid is a smaller molecule consisting of a carbamoylated cyclic guanidinyl moiety and a hydroxyl hexanoatemoiety.2) The total synthesis of guadinomic acid and guadinomines B and C2 have been reportedby Ōmura’s group3,5,6) (See Appendix-I).

H2N
O

Streptomyces sp. K01-0509
Bar: 1 µm

R1N
HN

NHOH
OH

O

R3H
N
R2H3C
O
CH3CH3N
H

OH
O
H 2N

R1R2

R3Guadinomine A

OH

NH2NH2

Guadinomine B

H

NH2NH2

Guadinomines C1 and C2(diastereomers at C-6')

H

H3C

O
NH

Guadinomine D

H

HN
O
HN

CH3O

N
HN

OH
NHOH

O

Guadinomic acid

NH22. Physical data (Guadinomine A)
White powder. C20H38N8O8; mol wt 518.56. Sol. in H2O, MeOH. Insol. in EtOAc, CHCl3.
3. Biological activity1)
1) Guadinomines A and B showed potent inhibition of TTSS-induced hemolysis with IC50 valuesof 0.02 and 0.007 µg/ml, respectively. Guadinomine D showed moderate activity (IC50: 8.5 µg/ml), but guadinomines C1, C2 and guadinomic acid exhibited no activity.

Guadinomine A ( ▲ ), B ( ■ ) and D ( ● ) and tetracycline ( ○ )2) All guadinomines showed no antimicrobial activity against yeasts, fungi and gram-positiveand gram-negative bacteria at 10 µg/6 mm disk by the paper disk method.

4. Biosynthesis4)
The biosynthetic gene cluster for guadinomine was identified and the biosynthetic pathway wasproposed. Guadinomines are synthesized from a unique guanidinoacetate starter unit by a chimeric multimodular polyketide synthase, a nonribosomal peptide synthetase, carbamoyltransferase
and tailoring enzymes.
5. Total synthesis5,6)
Below is scheme of the total synthesis of guadinomine C2 achieved by Ōmura’s group (See Appendix-I).
1) VinylMgBr, CuI,
98%O

BnO

BnO

2) BH 3•Me 2S; H 2O2
87%

OOHOH

1) BnBr, TBAI, NaH
89%

OHClNOOOTBDPSOOOOTBDPSO

OEt

p-NsN HOOO

TBDPSOO1) LiOH
H N
2) PyBOP, HOBt 2
DIPEA,
70% in 2 steps

O

O O
HN

O OO
O

3) TBAF, 79%

NH

Ot-Bu

1) SO 3•Py, DMSO, TEA
2) MeNO 2, DIPEA

NBoc

53%

O

BocN

NHBoc

3) I 2, PPh 3, imidazole
88%

OH

NH HN

HNONH HNNH

HN
O

Guadinomine C2t-Bu

O OO
HN
BocN

NBoc OONH HN
NBocHNOOH•TFA
Total steps; 34 steps from (R)-benzylglycidol
Overall yield; 0.42%

2) NaN 3
93% in 2 steps2) Boc 2O
68% in 2 steps

BrOt-Bu

HO1) p-NsCl, DMAP,TEA

1) PPh 3, TEA; H 2O

N3HN

OOEt

OEt

O

1) HCO 2NH 4, Pd / C2), MeCN
NN
57% in 2 steps

OH

HN

TBDPSO
Br

CHOO

N
H O

OOO

TBDPSOO

3) PPh 3, 76%O

3) 2,2-Dimethoxypropane
TsOH, 92%OOOH ONO

1) NaH, EtOH, 88%2) NaN 3, NH 4Cl,86% (2 cycles) TBDPSO

1) VinylMgBr
84% in 2 steps2) 4M HCl, 94%

OTBSOHC

1) TBDPSCl, imidazole2) H 2, Pd(OH) 2
78% in 2 steps
3) (COCl) 2, DMSO, TEA

OBn1) PhSH, DIPEA
65%O OON

2) PyBOP HO
DIPEA
95%O

NBocO

H 2NBn

OH O

N3OEt

HN

(+)-243

O2N

ClO

n-Bu2BOTf, TEA
65% in 2 steps

OO

Bn

OTBS

3) (COCl) 2, DMSO, TEAHO2) BH 3•Me 2S;
then BaBO 3,69%O

1) TBSCl, imidazole
95%2) H 2, Pd/C, 96%HNOt-BuCoNHOt-Bu

Ot-Bu

1) PMP isocyanate
2) CAN3) TFA
72% in 3 steps

t-Bu6. References
1. [1016] M. Iwatsuki et al., J. Antibiot. 61, 222-229 (2008)
2. [1017] M. Iwatsuki et al., J. Antibiot. 61, 230-236 (2008)
3. [925] S. Tsuchiya et al., Org. Lett. 8, 5577-5580 (2006)
4. [1132] T. C. Holmes et al., J. Am. Chem. Soc. 134, 17797-17806 (2012)
5. [1006] T. Hirose et al., Chem. Eur. J. 14, 8220-8238 (2008)
6. [1109] T. Hirose et al., J. Syn. Org. Chem., Jpn. 69, 775-788 (2011)