نتایج جستجو برای: flotaion reagents

تعداد نتایج: 28930  

2002
Paul Knochel

Organocopper reagents constitute a key class of organometallic reagents, with numerous applications in organic synthesis [1]. Their high reactivities and chemoselectivities have made them unique intermediates. Most reports use organocopper reagents of type 1 or 2, which are prepared from organolithiums. This transmetalation procedure confers optimal reactivity, but in many cases it permits only...

2003

INTRODUCTION Trifluoroacetic acid (TFA) is commonly used in the manufacturing process to release synthesized peptides from solid-phase resins. TFA or acetate is also used during reversed-phase HPLC purification of peptides. TFA is manufactured using acetate and fluoride as precursors, and residual levels of these compounds may be present whenever TFA is used. Residual TFA, fluoride, and, to a m...

Journal: :The Extractive Industries and Society 2022

Drawing on recent experimental and commercial developments, this review reappraises potential substitute leach reagents for cyanide in the gold mining sector. In addition to extraction, application of these processing, pre-treatment purification stages is explored. The main objective here discuss how extraction process can be more sustainable, with a view developing greener leaching reagents.

2006
F. BICKELHAUPT

Aliphatic ,w-dibromides can be converted to the corresponding c,w-di—Grignard reagents; for those members carrying less than four carbon atoms between the functions, special procedures are required. The synthesis, structure and applications of the di-Grignard reagents are discussed; particular emphasis is placed on the structures of the corresponding cyclic dialkylmagnesiums, and on the use of ...

Journal: :ACS Catalysis 2021

We describe a general catalytic methodology for the enantioselective dearomative alkylation of pyridine derivatives with Grignard reagents, allowing direct access to nearly enantiopure chiral dihydro-4-pyridones yields up 98%. The involves dearomatization in situ-formed N-acylpyridinium salts, employing alkyl organomagnesium reagents as nucleophiles and copper (I) complex catalyst. Computationa...

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