Exchange Of Building Blocks Research Articles

A Practical, Component-Based Synthetic Route to Methylthiolincosamine Permitting Facile Northern-Half Diversification of Lincosamide Antibiotics.

The development of a flexible, component-based synthetic route to the amino sugar fragment of the lincosamide antibiotics is described. This route hinges on the application and extension of nitroaldol chemistry to forge strategic bonds within complex amino sugar targets and employs a glycal epoxide as a versatile glycosyl donor for the installation of anomeric groups. Through building-block exchange and late-stage functionalization, this route affords access to a host of rationally designed lincosamides otherwise inaccessible by semisynthesis and underpins a platform for the discovery of new lincosamide antibiotics.

Irreversible Amide‐Linked Covalent Organic Framework for Selective and Ultrafast Gold Recovery

AbstractDesign of stable adsorbents for selective gold recovery with large capacity and fast adsorption kinetics is of great challenge, but significant for the economy and the environment. Herein, we show the design and preparation of an irreversible amide‐linked covalent organic framework (COF) JNU‐1 via a building block exchange strategy for efficient recovery of gold. JNU‐1 was synthesized through the exchange of 4,4′‐biphenyldicarboxaldehyde (BA) in mother COF TzBA consisting of 4,4′,4′′‐(1,3,5‐triazine‐2,4,6‐triyl)trianiline (Tz) and BA with terephthaloyl chloride. The irreversible amide linked JNU‐1 gave good stability, unprecedented fast kinetics, excellent selectivity and outstanding adsorption capacity for gold recovery. X‐ray photoelectron spectroscopy along with thermodynamic study and quantum mechanics calculation reveals that the excellent performance of JNU‐1 for gold recovery results from the formation of hydrogen bonds C(N)−H⋅⋅⋅Cl and coordinate interaction of O and Au. The rational design of irreversible bonds as both inherent linkage and functional groups in COFs is a promising way to prepare stable COFs for diverse applications.

Irreversible Amide-Linked Covalent Organic Framework for Selective and Ultrafast Gold Recovery.

Design of stable adsorbents for selective gold recovery with large capacity and fast adsorption kinetics is of great challenge, but significant for the economy and the environment. Herein, we show the design and preparation of an irreversible amide-linked covalent organic framework (COF) JNU-1 via a building block exchange strategy for efficient recovery of gold. JNU-1 was synthesized through the exchange of 4,4'-biphenyldicarboxaldehyde (BA) in mother COF TzBA consisting of 4,4',4''-(1,3,5-triazine-2,4,6-triyl)trianiline (Tz) and BA with terephthaloyl chloride. The irreversible amide linked JNU-1 gave good stability, unprecedented fast kinetics, excellent selectivity and outstanding adsorption capacity for gold recovery. X-ray photoelectron spectroscopy along with thermodynamic study and quantum mechanics calculation reveals that the excellent performance of JNU-1 for gold recovery results from the formation of hydrogen bonds C(N)-H⋅⋅⋅Cl and coordinate interaction of O and Au. The rational design of irreversible bonds as both inherent linkage and functional groups in COFs is a promising way to prepare stable COFs for diverse applications.

A building block exchange strategy for the rational fabrication of de novo unreachable amino-functionalized imine-linked covalent organic frameworks

A building block exchange strategy was developed for the fabrication of de novo unreachable ICOFs-NH2.

Mechanism of Building Block Exchange in Stacks of Self-Replicating Macrocycles

Self-replicating molecules containing labile reversible covalent bonds are becoming increasingly topical. Yet their robustness to component exchange and the threat of loss of information has received very little attention. We show here that supramolecular interactions can efficiently protect self-replicating molecules from otherwise rapid component exchange.

ChemInform Abstract: Constitutional Dynamic Chemistry: Bridge from Supramolecular Chemistry to Adaptive Chemistry

AbstractReview: 159 refs.

Par-delà la synthèse : l’auto-organisation

Abstract The evolution of the universe from the particle to the thinking organism has taken place through self-organization. Chemistry has a major role to play in understanding these processes leading to the generation of complex matter. Chemistry has developed a highly powerful molecular synthetic chemistry, mastering the combination and recombination of atoms into increasingly complex molecules through selective chemical reactions. Supramolecular chemistry is harnessing intermolecular forces for the generation of informed supramolecular systems and processes through supramolecular synthetic chemistry implementing molecular information carried by electromagnetic interactions. Supramolecular chemistry has been actively exploring systems undergoing self-organization, i.e., systems capable of spontaneously generating well-defined functional supramolecular architectures by self-assembly from their components, under the control of interactional molecular recognition events, thus behaving as programmed chemical systems. Molecular chemistry may similarly take advantage of the selectivity of covalent reactions to assemble complex molecular architectures through self-organization processes implementing functional molecular recognition. Supramolecular/non-covalent and molecular/covalent SELF-ORGANIZATION may thus be considered as the ULTIMATE SYNTHETIC CHEMISTRY, whereby chemical objects at both levels are generated on the basis of recognition processes involving either interactional or reactional features. Illustrations from the supramolecular domain will serve as illustrations. Supramolecular entities as well as molecules containing reversible bonds are able to undergo a continuous change in constitution by reorganization and exchange of building blocks. This capability defines a Constitutional Dynamic Chemistry (CDC) on both the molecular and supramolecular levels. CDC introduces a paradigm shift with respect to constitutionally static chemistry. It takes advantage of dynamic constitutional diversity to allow variation and selection and thus leads towards the emergence of adaptive and evolutive chemistry.

Towards Complex Matter: Supramolecular Chemistry and Self-organization

Chemistry has developed from molecular chemistry, mastering the combination and recombination of atoms into increasingly complex molecules, to supramolecular chemistry, harnessing intermolecular forces for the generation of informed supramolecular systems and processes through the implementation of molecular information carried by electromagnetic interactions. Supramolecular chemistry is actively exploring systems undergoing self-organization, i.e. systems capable of spontaneously generating well-defined functional supramolecular architectures by self-assembly from their components, on the basis of the molecular information stored in the covalent framework of the components and read out at the supramolecular level through specific molecular recognition interactional algorithms, thus behaving as programmed chemical systems. Supramolecular entities as well as molecules containing reversible bonds are able to undergo a continuous change in constitution by reorganization and exchange of building blocks. This capability defines a Constitutional Dynamic Chemistry (CDC) on both the molecular and supramolecular levels. CDC introduces a paradigm shift with respect to constitutionally static chemistry. It takes advantage of dynamic constitutional diversity to allow variation and selection and thus adaptation. The merging of the features of supramolecular systems – information and programmability; dynamics and reversibility; constitution and structural diversity – points towards the emergence of adaptive chemistry. A further development will concern the inclusion of the arrow of time, i.e. of non-equilibrium, irreversible processes and the exploration of the frontiers of chemical evolution towards the establishment of evolutive chemistry, where the features acquired by adaptation are conserved and transmitted. In combination with the corresponding fields of physics and biology, chemistry thus plays a major role in the progressive elaboration of a science of informed, organized, evolutive matter, a science of complex matter.

Chiral separation machinery using new crystalline inclusion hosts: Match/mismatch in the enantiomer recognition of (R,S)-1-methoxy-2-propanol effected by a borneol/fenchol building block exchange in the host molecule

New chiral host molecules 1 and 2 involving a bulky terpenoid unit and aromatic ethyne spacer groups were synthesized using Pd-catalyzed cross-coupling reactions of (+)-2α-ethynyl-2β-hydroxybornane (4) or (+)-2α-ethynyl-2β-hydroxyfenchane (5) with 9,10-dibromoanthracene. Host compounds 1 and 2 from crystalline inclusions with 1-methoxy-2-propanol (3) in 1:1 and 1:2 stoichiometry, respectively. In the case of 1, complete enantiomer resolution (ee > 99%) of 3 is effected in one cocrystallization step. However, constitutional isomer 2 failed in the enantiomer separation of 3, which might be explained due to the different crystal lattice buildup of these cocrystals. Chirality 9:203–210, 1997. © 1997 Wiley-Liss, Inc.