Replication data for synthesis of: "Natural and Nature-Inspired Catechol Siderophores: A Promising Strategy for Rice Blast Management"

For the preparation of catechol-bearing natural compounds protected 2,3-dihydroxybenzoic acid was used as a key precursor. Aminochelin was obtained as a trifluoroaceatate by reaction with N-Boc-1,4-diaminobutane using HATU and DIPEA in THF. The protecting groups were removed by hydrogenation (10% Pd/C catalyst), followed by treatment with TFA in dichloromethane.
The analogue containing a hydroxy group in place of the amino group on the side chain was obtained following a similar procedure with different aminobutanols. Same procedure for analogues containing the 3,4-dihydroxy substituted moiety in place of the 2,3-substituted one were obtained starting from the protected 3,4-dihydroxybenzoic
acid. The protecting groups were removed by hydrogenation (10% Pd/C catalyst).
Azotochelin was synthesized via amide coupling between protected 2,3-dihydroxybenzoic acid and L-lysine, followed by deprotection of the phenolic groups. In this case, the use of BBr3 resulted to be more advantageous than hydrogenation, which did not give a complete deprotection.
The reaction of protected 2,3-dihydroxybenzoic acid with L-lysine ethyl ester gave an intermediate, which was reduced with LiBH4 to obtain another compound which the removal of benzyl protecting groups by BBr3 afforded Myxochelin A.
Myxochelin A analogues were prepared following the same synthetic pathway reported above.
The reaction of the protected 2,3-dihydroxybenzoic acid with pentane-1,5-diamine,
followed by removal of the protecting group by BBr3 in dichloromethane, gave the corresponding diamide, which contained the same skeleton of Azotochelin and Myxochelin A, without the substituent on the connecting chain. The same approach was
followed to obtain other analogs.