摘要:
The present invention provides a process for preparing halogenated sulfones by reacting a halogenating agent with a salt of a hydroxysulfone. The halogenated sulfones are useful as an intermediate for vitamin A or its carboxylic acid esters employed as medicines or feed additives.
摘要:
A process for producing geranylgeraniol is provided, which comprises the steps of subjecting a mixture of at least one ester derivative wherein one or more carbon-carbon double bonds in the molecule are in cis form represented by the general formula (1):
wherein R represents an aromatic group which can be substituted with at least one substituent, or a higher aliphatic group having from 7 to 25 carbon atoms, and wavy lines, respectively, represent a state where each carbon-carbon double bond can be present in cis or trans form, and an ester derivative of the general formula (2):
wherein R is as defined above, to crystallization to obtain the ester derivative of the formula (2) selectively, and hydrolyzing the thus obtained ester derivative.
摘要:
A process for producing vitamin A acid, having useful biological activity, which comprises oxidizing vitamin A aldehyde with an aqueous solution of an alkali metal chlorite in the presence of an acid.
摘要:
The present invention provides a process for preparing halogenated sulfones by reacting a halogenating agent with a salt of a hydroxysulfone. The halogenated sulfones are useful as an intermediate for vitamin A or its carboxylic acid esters employed as medicines or feed additives.
摘要:
Provided is a process for producing canthaxanthin comprising the step of oxidizing β -carotene with an alkali metal chlorate or an alkali metal bromate in water and an organic solvent immiscible with water, wherein the oxidization reaction is started by adding:
a) an iodine halide or iodine, and b) a metal iodide, to a mixture of β-carotene, water, the organic solvent immiscible with water, and the alkali metal chlorate or the alkali metal bromate, which process can produce canthaxanthin for a short time, with efficiency and in an industrially advantageous manner.