135415-91-7

Upstream product

• 135415-90-6 (R)-2-hydroxy-2,4-dimethylpentanenitrile 
• 135362-76-4 (R)-2-Hydroxy-2,5-dimethyl-hexanenitrile 
• 3639-23-4 2-hydroxy-2,4-dimethylpentanoic acid 
• 108-10-1 4-methyl-2-pentanone 

Relevant academic research and scientific papers

Process Development and Crystallization in Oiling-Out System of a Novel Topical Antiandrogen

An efficient route to (S)-N-(2-bromo-6-methoxypyridin-4-yl)-2-hydroxy-2,4-dimethylpentanamide 1, a new topical antiandrogen, is described. The target compound has been manufactured on kilogram scale with an overall yield of 25% (HPLC purity 98.8% and >99% ee) from citrazinic acid. The key amide coupling between aminopyridine 4 and α-hydroxy-acid 6 was performed using a temporary protecting group to facilitate the acyl chloride formation. Aminopyridine 4 was manufactured from commercially available citrazinic acid via dibromide formation using phosphorus(V) oxybromide followed by mono SNAr reaction with sodium methoxide and a final Hofmann rearrangement. Enantiopure α-hydroxy-acid 6 was obtained using an enantioselective cyanosilylation followed by salt resolution with (S)-α-methyl benzylamine. The absolute configuration of compound 1 was determined with anomalous scattering and the final crystallization of API was performed after seeding a liquid-liquid mixture below the monotectic temperature and afforded a crystalline powder presenting a "desert rose" shape clusters.

METHOD FOR SYNTHESIZING ENANIOMERICALLY PURE N-(PYRIDIN-4-YL)-2-HYDROXY-ALKYLAMIDE DERIVATIVES

The present invention relates to a novel process for preparing enantiomerically pure compounds of N-(pyrid-4-yl)-2-hydroxyalkylamide type corresponding to the general formula (C) below: and also to processes for preparing the reaction intermediates used i

Enzyme-catalyzed synthesis of (R)-ketone-cyanohydrins and their hydrolysis to (R)-α-hydroxy-α-methyl-carboxylic acids

(R)-Ketone-cyanohydrins (R)-2 are obtained with high enantioselectivity from aliphatic ketones 1 and HCN in organic solvents using (R)-oxynitrilase ( EC 4.1.2.10) as catalyst. Acid catalyzed hydrolysis of the cyanohydrins (R)-2 affords the corresponding (R)-α-hydroxy-α-methyl-carboxylic acids (R)-3 without measurable racemization.