Jan. 31, 2013 ? Safe and inexpensive iron catalysts yield a ‘greener’ choice to standard curative prolongation methods.
More than one-quarter of all famous pharmaceuticals enclose a chemical organisation famous as amides: carboxylic poison derivatives subsequent from ammonia or amines. Most methods for synthesizing amides, however, are emasculate and use dangerous reagents. New work from Anqi Chen and co-workers during a A*STAR Institute of Chemical and Engineering Sciences in Singapore promises to make amide chemistry some-more careful and tolerable than before1. The group has unclosed a proceed to modify aldehydes and amine ipecac into amides regulating iron(II) sulfate — a harmless, inexpensive piece as a matter to perform this mutation well and with small waste.
Most choice methods to furnish amide molecules use costly eminent steel catalysts such as palladium and ruthenium, that are exclusive with industrial final for cost-efficiency. Funded by a GlaxoSmithKline (GSK)-Singapore Economic Development Board (EDB) capacity on tolerable drug manufacturing, a researchers investigated a opposite proceed famous as ‘direct oxidative amidation’. This process couples an aldehyde and an amine salt in a participation of a matter and an oxidant, generating an amide in one step.
Nontoxic and inexpensive catalysts with sufficient chemical activity for amide mutation are tough to find. To brand an fit and inexpensive catalyst, a group screened a operation of iron compounds and detected that iron(II) sulfate (see image), a addition for anemia that costs reduction than a dollar per kilogram, has clever intensity to catalyze amide arrangement from aldehydes with amine salts.
Apart from a environmentally soft iron catalyst, a mutation uses an inexpensive oxidant famous as tert-butyl hydroperoxide and really inexpensive calcium carbonate, a categorical combination of limestone, as a base. By mixing these inexpensive mixture together, a researchers achieved glorious amide yields underneath conditions available for both laboratory and industrial operations.
Further experiments suggested a flexibility of this amide synthesis. A operation of amine ipecac and aldehydes with opposite constructional and electronic facilities could be remade into amides with good-to-excellent yields. Importantly, ipecac subsequent from healthy amino acids such as valine and proline also underwent oxidative amidation but disrupting their chirality or ‘handedness’ — a vicious constructional materialisation for drug molecules and peptides.
The group demonstrated a intensity of this iron-catalyzed amidation for drug production by synthesizing a antiarrhythmic drug N-acetylprocainamide in a one-step procession that is some-more fit than prior multiple-step routes. “This environmentally soft process has poignant advantages over required techniques,†says Chen, “and we intend to brand curative targets where this earnest process could move about poignant cost-savings and softened sustainability.â€
The A*STAR-affiliated researchers contributing to this investigate are from a Institute of Chemical and Engineering Sciences
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The above story is reprinted from materials supposing by The Agency for Science, Technology and Research (A*STAR), around ResearchSEA.
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Journal Reference:
- Subhash Chandra Ghosh, Joyce S. Y. Ngiam, Christina L. L. Chai, Abdul M. Seayad, Tuan Thanh Dang and Anqi Chen. Iron-catalyzed fit singularity of amides from aldehydes and amine hydrochloride salts. Advanced Synthesis Catalysis, Volume 354, Issue 8, May 21, 2012, Pages: 1407%u20131412 DOI: 10.1002/adsc.201200020
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