Search results
Results from the WOW.Com Content Network
An example of a reaction proceeding in a S N 1 fashion is the synthesis of 2,5-dichloro-2,5-dimethylhexane from the corresponding diol with concentrated hydrochloric acid: [8] As the alpha and beta substitutions increase with respect to leaving groups, the reaction is diverted from S N 2 to S N 1.
Walden inversion is the inversion of a stereogenic center in a chiral molecule in a chemical reaction. Since a molecule can form two enantiomers around a stereogenic center, the Walden inversion converts the configuration of the molecule from one enantiomeric form to the other.
The Fischer indole synthesis is a chemical reaction that produces the aromatic heterocycle indole from a (substituted) phenylhydrazine and an aldehyde or ketone under acidic conditions. [19] [20] The reaction was discovered in 1883 by Hermann Emil Fischer. The Fischer indole synthesis. The choice of acid catalyst is very important.
In the second step, the nucleophilic reagent (Nuc:) attaches to the carbocation and forms a covalent sigma bond. If the substrate has a chiral carbon, this mechanism can result in either inversion of the stereochemistry or retention of configuration. Usually, both occur without preference. The result is racemization.
A polymerase chain reaction is a form of enzymatic DNA synthesis in the laboratory, using cycles of repeated heating and cooling of the reaction for DNA melting and enzymatic replication of the DNA. DNA synthesis during PCR is very similar to living cells but has very specific reagents and conditions.
As DNA synthesis continues, the original DNA strands continue to unwind on each side of the bubble, forming a replication fork with two prongs. In bacteria, which have a single origin of replication on their circular chromosome, this process creates a "theta structure" (resembling the Greek letter theta: θ). In contrast, eukaryotes have longer ...
Mitotic DNA synthesis (MiDAS) is a process of irregular DNA replication where DNA synthesis, naturally occurring in the S phase, takes place in the M phase of the cell cycle. Mitotic DNA synthesis is known to occur when cells are experiencing stress related to DNA replication . [ 151 ]
The Darzens reaction (also known as the Darzens condensation or glycidic ester condensation) is the chemical reaction of a ketone or aldehyde with an α-haloester in the presence of a base to form an α,β-epoxy ester, also called a "glycidic ester".