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The Ugi reaction has been applied in combination with an intramolecular Diels-Alder reaction [16] in an extended multistep reaction. A reaction in its own right is the Ugi–Smiles reaction with the carboxylic acid component replaced by a phenol. In this reaction the Mumm rearrangement in the final step is replaced by the Smiles rearrangement. [17]
These strategies can be grouped into approaches for managing reaction sequences. Reaction Sequences: Multistep synthesis involves sequential chemical reactions, each requiring its own work-up to isolate intermediates before proceeding to the next stage. [4] For example, the synthesis of paracetamol typically requires three separate reactions.
Using the twenty natural amino acids, for example, in a tripeptide creates 8,000 (20 3) possibilities. Solid-phase methods for small molecules were later introduced and Furka devised a "split and mix" approach [2] [4] In its modern form, combinatorial chemistry has probably had its biggest impact in the pharmaceutical industry. [5]
In organic chemistry, a cross-coupling reaction is a reaction where two different fragments are joined. Cross-couplings are a subset of the more general coupling reactions. Often cross-coupling reactions require metal catalysts. One important reaction type is this:
Salt metathesis reaction; Salt-free reduction; Scavenger resin; Screaming jelly babies; SEA Native Peptide Ligation; Self-assembling peptide; Semiclassical transition state theory; Shiina esterification; Side reaction; Single displacement reaction; Small molecule sensors; Solid-state reaction route; Spin-forbidden reactions; Stripping reaction ...
The Barton reaction involves a homolytic RO–NO cleavage, followed by δ-hydrogen abstraction, free radical recombination, and tautomerization to form an oxime. [3] Selectivity for the δ-hydrogen is a result of the conformation of the 6-membered radical intermediate. Often, the site of hydrogen atom abstraction can be easily predicted.
A multi-component reaction (or MCR), sometimes referred to as a "Multi-component Assembly Process" (or MCAP), is a chemical reaction where three or more compounds react to form a single product. [1] By definition, multicomponent reactions are those reactions whereby more than two reactants combine in a sequential manner to give highly selective ...
Nef reaction in combination with Michael addition. In carbohydrate chemistry, they are a chain-extension method for aldoses, as in the isotope labeling of C 14-D‑mannose and C 14-D‑glucose from D‑arabinose and C 14 ‑nitromethane (the first step here is a Henry reaction): The Nef reaction: chain extension. The opposite reaction is the ...