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Efectos conformamentales en la reactividad de los glucósidos: estudio del conformador altamente reactivo de la
Ciaran McDonnell1, Oscar López, Paul Murphy
1Department of Chemistry, University College Dublin, Ireland.
Journal of the American Chemical Society
|September 30, 2004
Resumen
La conformación de los glucósidos tiene un impacto significativo en su reactividad. Específicamente, la conformación (1)C(4) aumenta drásticamente las tasas de hidrólisis, apoyando las teorías sobre los efectos del grupo hidroxilo axial.
Área de la Ciencia:
- Química de los carbohidratos Química de los carbohidratos
- Química orgánica es la química orgánica.
- Química biofísica y bioquímica.
Sus antecedentes:
- La conformación de los glucósidos es crucial para comprender la reactividad de los carbohidratos.
- Se propone la conformación (1)C(4) para mejorar la reactividad.
- Estudios previos sugieren que los grupos hidroxilo axiales influyen en la retirada de electrones.
Objetivo del estudio:
- Para investigar el efecto de la conformación en la reactividad de los glucósidos.
- Utilizar 3,6-anhidroglucósidos como modelos para la conformación reactiva (1)C(4) de la glucosa.
- Para comparar la reactividad de diferentes derivados de anhidroglucósidos.
Principales métodos:
- Síntesis de metil 3,6-anhidroglucósidos y oligosacáridos relacionados.
- Estudios de la velocidad de hidrólisis en condiciones controladas.
- Análisis conformacional de los glucósidos estudiados.
Principales resultados:
- Metil 3,6-anhidro-beta-D-glucopiranósido hidrolizado 200-400 veces más rápido que los (4) C(1) glucósidos de metilo.
- El metil 3,6-anhidro-beta-D-galactopiranósido mostró una reactividad reducida en comparación con el metil beta-D-galactopiranósido.
- Los oligosacáridos sintetizados reaccionaron selectivamente con el residuo anhidro.
Conclusiones:
- La conformación (1)C(4) de los glucósidos los convierte en especies altamente reactivas.
- Esta mayor reactividad apoya la hipótesis de que los grupos OH axiales son menos recolectores de electrones que los grupos OH ecuatoriales.
- Los efectos de conformación son un determinante clave en las tasas de hidrólisis de los glucósidos.
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