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The Criegee oxidation is a glycol cleavage reaction in which vicinal diols are oxidized to form ketones and aldehydes using lead tetraacetate. It is analogous to the use of periodate (Malaprade reaction) but uses a milder oxidant. This oxidation was discovered by Rudolf Criegee and coworkers and first reported in 1931 using ethylene glycol as ...
Lead(IV) acetate or lead tetraacetate is an metalorganic compound with chemical formula Pb(C 2 H 3 O 2) 4. It is a colorless solid that is soluble in nonpolar, organic solvents, indicating that it is not a salt. It is degraded by moisture and is typically stored with additional acetic acid. The compound is used in organic synthesis. [2]
Another reagent is lead tetraacetate (Pb(OAc) 4). [4] These I- and Pb-based methods are called the Malaprade reaction and Criegee oxidation, respectively. The former is favored for aqueous solutions, the latter for nonaqueous solutions. [1] Cyclic intermediate are invariably invoked. The ring then fragments, with cleavage of the carbon–carbon ...
Most commonly, including steroidal systems, the hydrogen atom is abstracted from a methyl group that has a 1,3 diaxial relationship with the alkoxyl radical. [15] In the absence of a hydrogen on the δ-carbon, or when the particular conformation of the substrate orients the ε-carbon close together, 1,6-hydrogen atom transfer is the favored ...
The Hofmann rearrangement (Hofmann degradation) is the organic reaction of a primary amide to a primary amine with one less carbon atom. [1] [2] [3] The reaction involves oxidation of the nitrogen followed by rearrangement of the carbonyl and nitrogen to give an isocyanate intermediate.
In extreme cases the periodate may be exchanged for lead tetraacetate which reacts in a similar manner and is soluble in organic solvents (Criegee oxidation). Periodate cleavage is often utilized in molecular biochemistry for the purposes of modifying saccharide rings, as many five- and six-membered sugars have vicinal diols. Historically it ...
Autoxidation (sometimes auto-oxidation) refers to oxidations brought about by reactions with oxygen at normal temperatures, without the intervention of flame or electric spark. [1] The term is usually used to describe the gradual degradation of organic compounds in air at ambient temperatures.
Lead(II) oxide is also soluble in alkali hydroxide solutions to form the corresponding plumbite salt. [2] PbO + 2 OH − + H 2 O → Pb(OH) 2− 4. Chlorination of plumbite solutions causes the formation of lead's +4 oxidation state. Pb(OH) 2− 4 + Cl 2 → PbO 2 + 2 Cl − + 2 H 2 O. Lead dioxide is representative of the +4 oxidation state ...