High Fidelity Kinetic Self-Sorting in Multi-Component Systems Based on Guests with Multiple Binding Epitopes
摘要:
The molecular recognition platforms of natural systems often possess multiple binding epitopes, each of which has programmed functional consequences. We report the dynamic behavior of a system comprising CB[6], CB[7], and guests cyclohexanediammonium (1) and adamantanealkylammonium (2) that we refer to as a two-faced guest because it contains two distinct binding epitopes. We find that the presence of the two-faced guests-just as is observed for protein targeting in vivo-dictates the kinetic pathway that the system follows toward equilibrium. The influence of two-faced guest structure, cation concentration, cation identity, and individual rate and equilibrium constants on the behavior of the system was explored by a combination of experiment and simulation. Deconstruction of this system led to the discovery of an anomalous host-guest complex (CB[6]center dot 1) whose dissociation rate constant (k(out) = 8.5 x 10(-10) s(-1)) is approximate to 100-fold slower than the widely used avidin, biotin affinity pair. This result, in combination with the analysis of previous systems which uncovered extraordinarily tight binding events (K-a >= 10(12) M-1), highlights the inherent potential of pursuing a systems approach toward supramolecular chemistry.
N-alkylation of tert-alkylamines applying aliphatic amines is described for the first time. In the presence of the Shvo catalyst 1, tert-octylamine 4 and 1-adamantylamine 5 are alkylated using primary, secondary, and even tertiary amines to give the corresponding monoalkylated tert-alkylamine in moderate to very good yields and excellent selectivity. This novel reaction proceeds without an additional
High Fidelity Kinetic Self-Sorting in Multi-Component Systems Based on Guests with Multiple Binding Epitopes
作者:Pritam Mukhopadhyay、Peter Y. Zavalij、Lyle Isaacs
DOI:10.1021/ja063390j
日期:2006.11.1
The molecular recognition platforms of natural systems often possess multiple binding epitopes, each of which has programmed functional consequences. We report the dynamic behavior of a system comprising CB[6], CB[7], and guests cyclohexanediammonium (1) and adamantanealkylammonium (2) that we refer to as a two-faced guest because it contains two distinct binding epitopes. We find that the presence of the two-faced guests-just as is observed for protein targeting in vivo-dictates the kinetic pathway that the system follows toward equilibrium. The influence of two-faced guest structure, cation concentration, cation identity, and individual rate and equilibrium constants on the behavior of the system was explored by a combination of experiment and simulation. Deconstruction of this system led to the discovery of an anomalous host-guest complex (CB[6]center dot 1) whose dissociation rate constant (k(out) = 8.5 x 10(-10) s(-1)) is approximate to 100-fold slower than the widely used avidin, biotin affinity pair. This result, in combination with the analysis of previous systems which uncovered extraordinarily tight binding events (K-a >= 10(12) M-1), highlights the inherent potential of pursuing a systems approach toward supramolecular chemistry.