Synthesis of 2-Methoxy-4-(methylsulfanyl)benzoic Acid — An Intermediate Product in the Preparation of the Cardiotonic Drugs Sulmazole and Isomazole
摘要:
Readily available 4-methyl-3-nitrobenzenesulfonic acid and 2-methyl-5-nitrophenol were used to develop two alternative approaches to the synthesis of 2-methoxy-4-(methylsulfanyl)benzoic acid in total yields of 17% and 37%, respectively. The synthesis starting from 2-methyl-5-nitrophenol is more process-oriented and can be used in the resynthesis of Sulmazole and Isomazole.
Synthesis of 2-Methoxy-4-(methylsulfanyl)benzoic Acid — An Intermediate Product in the Preparation of the Cardiotonic Drugs Sulmazole and Isomazole
摘要:
Readily available 4-methyl-3-nitrobenzenesulfonic acid and 2-methyl-5-nitrophenol were used to develop two alternative approaches to the synthesis of 2-methoxy-4-(methylsulfanyl)benzoic acid in total yields of 17% and 37%, respectively. The synthesis starting from 2-methyl-5-nitrophenol is more process-oriented and can be used in the resynthesis of Sulmazole and Isomazole.
The subject of the present invention is a method for the hydroxylation of phenol by hydrogen peroxide. The method of the invention for the hydroxylation of phenol to pyrocatechol and hydroquinone in a pyrocatechol/hydroquinone ratio between 1.7 and 2.3, by reaction of the phenol with hydrogen peroxide, in the presence of a catalyst, is characterized by the fact that the reaction is carried out in the presence of an effective amount of a hydroxyaromatic sulfonic acid.
Method for hydroxylating phenols and phenol ethers
申请人:Garel Laurent
公开号:US20140073818A1
公开(公告)日:2014-03-13
A method for hydroxylating phenols and phenol ethers using hydrogen peroxide and specifically, a method for hydroxylating phenol using hydrogen peroxide. The method for hydroxylating a phenolic substrate selected from a phenol or a phenol ether by reacting such phenolic substrate with hydrogen peroxide in the presence of an acid catalyst comprises the following steps, implemented consecutively or simultaneously: a first step consisting of mixing a phenolic substrate with a hydrogen peroxide solution under conditions in which the temperature is sufficient for the initial phenolic substrate to remain liquid and for minimizing the conversion rate of the hydrogen peroxide; a second step consisting of carrying out the phenolic substrate hydroxylation reaction under adiabatic conditions, the acid catalyst being added at the mixing stage and/or at the beginning of the hydroxylation reaction; and a third step, if necessary, consisting of recovering the hydroxylated product.
METHOD FOR THE HYDROXYLATION OF PHENOLS AND PHENOL ETHERS
申请人:Garel Laurent
公开号:US20140221698A1
公开(公告)日:2014-08-07
The present invention relates to a method for the hydroxylation of phenols and phenol ethers by means of hydrogen peroxide. The invention specifically relates to a method for the hydroxylation of phenol by means of the hydrogen peroxide. The method of the invention for the hydroxylation of a phenol ether by means of reacting said phenol or phenol ether with the hydrogen peroxide in the presence of an acid catalyst is characterized in that it includes mixing a phenol or phenol ether with a hydrogen peroxide solution in a mixing device under conditions enabling the conversion rate of the hydrogen peroxide to be minimized, and in that said reaction mixture is then placed in a piston flow reactor where the reaction leading to the production of the hydroxylated material takes place, the acid catalyst being fed into the mixing device and/or into the piston flow reactor.
PROCESS FOR THE HYDROXYLATION OF PHENOLS AND OF PHENOL ETHERS
申请人:Garel Laurent
公开号:US20120035397A1
公开(公告)日:2012-02-09
A process for the hydroxylation of phenols and of phenol ethers by hydrogen peroxide is described. More particularly a process for the hydroxylation of phenol by hydrogen peroxide is described. The described process can include hydroxylation of a phenol or of a phenol ether having at least one hydrogen atom at the ortho and para position of the hydroxyl group or of the ether group, by reaction of said phenol or phenol ether, with hydrogen peroxide, in the presence of an acid catalyst, wherein the reaction is carried out in the presence of an effective amount of a catalyst which is a mixture of at least two strong acids and wherein one of the acids is chosen from strong protonic acids and the other acid is chosen from superacids.
A photochromic compound suitable for use as a single substance for photochromic tinting of a transparent plastic article so that the tinted article has a neutral gray or brown color in the excited state, is made by fusing at least two non-identical photochromic sections to an aromatic structure. The photochromic sections are selected so that the different absorption wavelengths of the excited photochromic sections give rise to a neutral gray or brown color in the plastic material and are selected from the group consisting of oxazines and pyrans. At least one of the photochromic sections is not an indolino spiropyran. The aromatic structure to which the photochromic sections are fused is selected from the group consisting of benzene, biphenyl, naphthalene, anthracene and phenanthrene. The positions of fusion of the photochromic sections on the aromatic structure are directly adjacent to the oxygen atom of the pyran or the oxygen or nitrogen atom of the oxazine.