Soley, Jacob published the artcileMild, Rapid, and Chemoselective Procedure for the Introduction of the 9-Phenyl-9-fluorenyl Protecting Group into Amines, Acids, Alcohols, Sulfonamides, Amides, and Thiols, Formula: C11H22N2O4, the publication is Journal of Organic Chemistry (2020), 85(4), 2068-2081, database is CAplus and MEDLINE.
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 Me esters of amino acids, as well as into alcs. 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 quant. yields, by treatment with N,O-bis(trimethylsilyl)acetamide (BSA) and then PhFCl/NMM/AgNO3. Primary alcs. can be protected with the PhF group in the presence of secondary alcs. in moderate yield. Using PhFCl/AgNO3, a primary alc. 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 alc. (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.
Journal of Organic Chemistry published new progress about 2418-95-3. 2418-95-3 belongs to amides-buliding-blocks, auxiliary class Chiral,Carboxylic acid,Amine,Aliphatic hydrocarbon chain,Ester,Amino acide derivatives, name is H-Lys(Boc)-OH, and the molecular formula is C38H74Cl2N2O4, Formula: C11H22N2O4.
Referemce:
https://en.wikipedia.org/wiki/Amide,
Amide – an overview | ScienceDirect Topics