摘要:
Processes for preparing N-methyl-L-alanine derivatives and novel intermediates of the process. The derivatives and intermediates are useful for preparing cell-binding agent/maytansinoid complexes.
摘要:
A process for the preparation of highly pure 1-(mercaptomethyl)-cyclopropaneacetic acid is described. Treatment of 1-(hydroxymethyl)-cyclopropaneacetonitrile with an acid provides the corresponding imino ester and/or halo-amide, which when reacted with thiourea provides the corresponding amide-isothiuronium salt. Hydrolysis of the amide-isothiuronium salt followed by an in situ oxidation allows the facile isolation and purification of 1-[1-(carboxymethyl)-cyclopropanemethyldisulfanylmethyl]-cyclopropaneacetic acid (also known as 1-(mercaptomethyl)-cyclopropaneacetic acid disulfide). Reduction of the 1-(mercaptomethyl)-cyclopropaneacetic acid disulfide under mild conditions provides the 1-(mercaptomethyl)-cyclopropaneacetic acid with high purity.
摘要:
A process which can be used to produce an organic disulfide is provided. The process comprises contacting a mercaptan in the presence of an oxygen-containing fluid, a catalyst, optionally a cocatalyst, and further optionally a solvent or a surfactant or combination of a solvent and surfactant under a condition sufficient to oxidize the mercaptan to an organic disulfide.
摘要:
A process for producing an organic polysulfide compound comprises contacting, in th presence of a catalyst, a mercaptan with elemental sulfur to produce a product medium and contacting the product medium with a material comprising carbon dioxide or a carbon dioxide-generating compound wherein the catalyst comprises a base and optionally a surfactant and the organic polysulfide contains about 3 or more sulfur atoms per molecule.
摘要:
The present invention discloses a process for the preparation of aromatic thiophenol represented by the formula (I):
Y n -Ar-(SH) m (I)
wherein Ar represents an aromatic hydrocarbon residue; Y represents at least one kind of substituent bonded to a carbon atom constituting the aromatic ring of Ar, which is selected from the group consisting of halogeno, nitro, nitrile, sulfone, sulfamoyl and hydrocarbylsulfonyl groups; m is an integer of 1 or more; and n is 0 or an integer of 1 or more, which comprises reacting aromatic thioether represented by the formula (II):
Y n -Ar-(SR) m (II)
wherein R represents a monovalent secondary or tertiary hydrocarbyl, or a monovalent primary hydrocarbyl group represented by the formula:
-CH 2 -R 1 or -CH 2 -CR 2 =C(R 2 ) 2 ;
where R 1 represents a monovalent aromatic ring group optionally substituted by a monovalent hydrocarbyl group, and each of R 2 may be the same as or different from each other and represents hydrogen or a monovalent hydrocarbyl group;
Y, Ar, m and n have the same meanings as defined above, in the presence of (A) a Lewis acid or a protonic acid provided that in the case of a protonic acid, primary hydrocarbyl group is excluded from R, and a solvent, and, if necessary, hydrolyzing the reaction product.
摘要:
A method for achieving improved conversion rates and/or a faster reaction rate, particularly in reaction (a), than those achievable with prior art resins.
摘要:
A composition comprising a base and an alkoxylated compound selected from an alkoxylated alcohol and alkoxylated mercaptan is disclosed. The composition can be used to catalyze the reaction of a mercaptan and an elemental sulfur to produce a polysulfide compound. The polysulfide compound can be further treated with an alkylene oxide to reduce the mercaptan sulfur content of the polysulfide compound.