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Synthesis and antioxidant evaluation of enantiomerically pure bis-(1,2,3-triazolylmethyl)amino esters from modified α-amino acids.

Sarmiento-Sánchez JI, Ochoa-Terán A, Rivero IA - ScientificWorldJournal (2014)

Bottom Line: The antioxidant activity of compounds 6 was assayed by DPPH method.The compound 6c with an IC50 of 75.57 ± 1.74 μg mL(-1) was the most active.Technically, this methodology allows the preparation of a combinatorial library of analogues with different structural characteristics depending on the nature of the modified α-amino acids employed in the synthesis.

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Affiliation: Facultad de Ingeniería, Universidad Autónoma de Sinaloa, Boulevard de las Américas S/N, 80040 Culiacán, SIN, Mexico.

ABSTRACT
The efforts for synthesis of enantiomerically pure bis-(1,2,3-triazolylmethyl)amino esters 6 are reported in good yields from an in situ generated α-azidomethyl ketone. Optimum experimental conditions were established for preparation of α-halomethyl ketones 10 and α-N,N-dipropargylamino esters 11, all derived from α-amino acids. The starting materials reacted under conventional click chemistry conditions, revealing a specific reactivity of bromomethyl ketones over chloromethyl ketones. The antioxidant activity of compounds 6 was assayed by DPPH method. The compound 6c with an IC50 of 75.57 ± 1.74 μg mL(-1) was the most active. Technically, this methodology allows the preparation of a combinatorial library of analogues with different structural characteristics depending on the nature of the modified α-amino acids employed in the synthesis.

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Synthesis of starting compounds from α-amino acids.
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sch2: Synthesis of starting compounds from α-amino acids.

Mentions: The synthesis of enantiopure α-halomethyl ketones 10 and α-N,N-dipropargylamino esters 11 can be achieved following the methodology depicted in Scheme 2. α-Amino acids 7 were esterified with excellent yields using trimethylsilyl chloride (TMSCl) and methanol or ethanol as solvent. Then, compounds 8 are alkylated under basic conditions using benzyl bromide to obtain N,N-dibenzylamino esters 9, which react with methyllithium chloride or methyllithium bromide in situ generated in order to obtain the enantiopure compounds 10. The α-halomethyl ketones synthesized only were characterized for NMR and immediately used for the next step in the reaction. Yields for the α-halomethyl ketones synthesized with this procedure are shown in Table 1.


Synthesis and antioxidant evaluation of enantiomerically pure bis-(1,2,3-triazolylmethyl)amino esters from modified α-amino acids.

Sarmiento-Sánchez JI, Ochoa-Terán A, Rivero IA - ScientificWorldJournal (2014)

Synthesis of starting compounds from α-amino acids.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4216715&req=5

sch2: Synthesis of starting compounds from α-amino acids.
Mentions: The synthesis of enantiopure α-halomethyl ketones 10 and α-N,N-dipropargylamino esters 11 can be achieved following the methodology depicted in Scheme 2. α-Amino acids 7 were esterified with excellent yields using trimethylsilyl chloride (TMSCl) and methanol or ethanol as solvent. Then, compounds 8 are alkylated under basic conditions using benzyl bromide to obtain N,N-dibenzylamino esters 9, which react with methyllithium chloride or methyllithium bromide in situ generated in order to obtain the enantiopure compounds 10. The α-halomethyl ketones synthesized only were characterized for NMR and immediately used for the next step in the reaction. Yields for the α-halomethyl ketones synthesized with this procedure are shown in Table 1.

Bottom Line: The antioxidant activity of compounds 6 was assayed by DPPH method.The compound 6c with an IC50 of 75.57 ± 1.74 μg mL(-1) was the most active.Technically, this methodology allows the preparation of a combinatorial library of analogues with different structural characteristics depending on the nature of the modified α-amino acids employed in the synthesis.

View Article: PubMed Central - PubMed

Affiliation: Facultad de Ingeniería, Universidad Autónoma de Sinaloa, Boulevard de las Américas S/N, 80040 Culiacán, SIN, Mexico.

ABSTRACT
The efforts for synthesis of enantiomerically pure bis-(1,2,3-triazolylmethyl)amino esters 6 are reported in good yields from an in situ generated α-azidomethyl ketone. Optimum experimental conditions were established for preparation of α-halomethyl ketones 10 and α-N,N-dipropargylamino esters 11, all derived from α-amino acids. The starting materials reacted under conventional click chemistry conditions, revealing a specific reactivity of bromomethyl ketones over chloromethyl ketones. The antioxidant activity of compounds 6 was assayed by DPPH method. The compound 6c with an IC50 of 75.57 ± 1.74 μg mL(-1) was the most active. Technically, this methodology allows the preparation of a combinatorial library of analogues with different structural characteristics depending on the nature of the modified α-amino acids employed in the synthesis.

Show MeSH