140422-54-4Relevant articles and documents
Straightforward synthesis of fluorinated amino acids by Michael addition of ethyl bromodifluoroacetate to α,β-unsaturated α-amino acid derivatives
Kondratov, Ivan S.,Bugera, Maxym Ya.,Tolmachova, Nataliya A.,Daniliuc, Constantin G.,Haufe, Günter
, p. 100 - 108 (2018)
Copper-mediated Michael addition of ethyl bromodifluoroacetate to N-protected α,β-unsaturated α-amino acid esters was applied for straightforward synthesis of γ,γ-difluorinated analogues of glutamic acid (compound 1) and glutamine (compound 10). Moreover, a proline-based, sterically constrained analog of γ,γ-difluoroglutamic acid (compound 24) was prepared.
METHODS OF SYNTHESIZING AZTREONAM DERIVATIVES
-
Paragraph 408, (2020/11/03)
Disclosed herein are aztreonam derivatives, therapeutic methods of using the aztreonam derivatives, and methods of synthesizing aztreonam derivatives. The aztreonam derivatives can be administered orally to provide orally bioavailable aztreonam.
Mild, Rapid, and Chemoselective Procedure for the Introduction of the 9-Phenyl-9-fluorenyl Protecting Group into Amines, Acids, Alcohols, Sulfonamides, Amides, and Thiols
Soley, Jacob,Taylor, Scott D.
, (2020/02/04)
The 9-phenyl-9-fluorenyl (PhF) group has been used as an Nα protecting group of amino acids and their derivatives mainly as a result of its ability to prevent racemization. However, installing this group using the standard protocol, which employs 9-bromo-9-phenylfluorene/K3PO4/Pb(NO3)2, often takes days and yields can be variable. Here, we demonstrate that the PhF group can be introduced into the amino group of Weinreb's amides and methyl esters of amino acids, as well as into alcohols and carboxylic acids, rapidly and in excellent yields, using 9-chloro-9-phenylfluorene (PhFCl)/N-methylmorpholine (NMM)/AgNO3. Nα-PhF-protected amino acids can be prepared from unprotected α-amino acids, rapidly and often in near quantitative yields, by treatment with N,O-bis(trimethylsilyl)acetamide (BSA) and then PhFCl/NMM/AgNO3. Primary alcohols can be protected with the PhF group in the presence of secondary alcohols in moderate yield. Using PhFCl/AgNO3, a primary alcohol can be protected in good yield in the presence of a primary ammonium salt or a carboxylic acid. Primary sulfonamides and amides can be protected in moderate to good yields using phenylfluorenyl alcohol (PhFOH)/BF3·OEt2/K3PO4, while thiols can be protected in good to excellent yield using PhFOH/BF3·OEt2 even in the presence of a carboxylic acid or primary ammonium group.
