摘要:
Process to reduce stereoselectively 3alpha-hydroxy-7-keto-5beta-cholanic acid to 3alpha,7beta-dihydroxy-5beta-cholanic acid in ter.alcohols by using, as reducing agent, sodium metal in the presence of other metal salts.Examples of metal salts particularly useful are: potassium, cesium and rhubidium organic salts and, more particularly, potassium acetate or potassium ter.butylate.
摘要:
A process is described for the preparation of 2-methoxy-6-propionyl-naphthalene, an intermediate in the synthesis of naproxen.The process consists of Friedel-Crafts acylation of 2-methoxy-naphthalene, and obviates the drawbacks related to the use of nitrobenzene as solvent.
摘要:
Process for carboxylating 2',4'-difluoro-4-hydroxy-1,1'-diphenyl or a derivative thereof with an alkaline alkylcarbonate at atmospheric pressure to afford 2',4'-difluoro-4-hydroxy-(1,1'-diphenyl)-3-carboxylic acid.
摘要:
A stereoselective process is described for preparing optically active alpha,beta-disubstituted carbonyl compounds, comprising forming an acetal between an alpha,beta-unsaturated aldehyde or ketone and tartaric acid or a derivative thereof, halogenating the product thus obtained, and restoring the carbonyl compound.
摘要:
A process is described for the preparation of alpha-hydroxyl-alkanoic acids of formula ##STR1## which are known anti-inflammatory agents or intermediates for known pharmaceutical products. The process consists essentially in the rearrangement of phenolates of formula ##STR2## wherein Ar is an unsubstituted or substituted phenyl or naphthyl, in aqueous environment or in an organic medium, at temperatures comprised within the range of from 0.degree. to 100.degree. C. and within short times, followed by either acid or alkaline hydrolysis.
摘要:
A process for the preparation of 5-(2,4-difluorophenyl)-salicylic acid comprising the reaction of an organometallic derivative with a suitable substituted benzene in the presence of a transition-metal based catalyst is described.
摘要:
A process for the preparation of 5-(2,4-difluorophenyl)-salicylic acid comprising the reaction of an organometallic derivative with a suitable substituted benzene in the presence of a transition-metal based catalyst is described.
摘要:
The invention relates to a new process for the production and/or purification of the salt of the compound (S)-2-[4-(2-fluorobenzyloxy)benzylamino]propanamide, i.e. ralfinamide, or the respective R-enantiomer, with methanesulfonic acid in high yields and very high enantiomeric and chemical purity in the form of the crystalline anhydrous polymorph identified as form A, wherein said salt is substantially free from impurities having genotoxic effect, such as (C1-C5)alkanylmethanesulfonates, and residual solvents known as potential precursors thereof, such as (C1-C5)alkanols or esters thereof with lower alkanoic acids.The process foresees (i) production and/or crystallization of the salt, from water, acetone, an aliphatic ketone of 4-5 carbon, atoms or mixtures thereof with water, or (ii) slurring the solid salt with (a) water, (b) a mixture of water with acetone or an aliphatic ketone of 4-5 carbon atoms, (c) acetone, an aliphatic ketone of 4-5 carbon atoms or a mixture thereof, or (iii) exposure of the solid salt to air stream having high degree of relative humidity, and, when the obtained product consists as a whole or in part of crystalline hemihydrate pseudopolymorph form H crystals, converting said product into anhydrous form A crystals by submitting it to water removal.The crystalline hemihydrate pseudopolymorph form H of ralfinamide methanesulfonate, or its R-enantiomer, is a useful intermediate for obtaining the crystalline anhydrous polymorph A free from the above impurities having genotoxic effect and/or residual solvents known as precursors thereof, and exhibits a physicochemical profile conferring significant advantages in the design and development of solid dosage forms, in particular, of modified release formulations.
摘要:
A process is described for the preparation of arylpyridine compounds by aryl-aryl cross-coupling reactions between a halopyridine and an arylmagnesium halide carried out in the presence of a catalytic amount of a zinc salt and a catalytic amount of palladium. The zinc salt is preferably selected from ZnCl2, ZnBr2 and/or Zn(OAc)2, while the palladium is preferably used in the form of Pd(PPh3)4 or Pd(OAc)2 +4 PPh3. The reaction can also be carried out in the presence of bidentate phosphines, such as, for example, 1,3-bis(diphenylphosphine)propane or 1,4-bis(diphenylphosphine)-butane. It is thus possible to obtain molar yields higher than 97% (calculated relative to the halopyridine) and a catalyticity of more than 2000.