Preparation of Benzyl and p-Nitrobenzyl Esters of Amino Acids¹

Solid-phase acyl donor as a substrate pool in kinetically controlled protease-catalysed peptide synthesis

“…Esterification of H-His-OH*2 BzSO 3 H with HONb to obtain H-His-ONb*2 BzSO 3 H was performed according to Shields et al [16]. All other amino acids derivatives were purchased from BACHEM Biochemica GmbH (Heidelberg, Germany) or taken from our laboratory stock.…”

Metal Complexes of Biologically Important Ligands, CLXXII [1]. Metal Ions and Metal Complexes as Protective Groups of Amino Acids and Peptides – Reactions at Coordinated Amino Acids

“…A first example was reported by Synge [16], e. g. the synthesis of L-valyl-L-ornithine by reaction of carbobenzoxy-L-valyl chloride with N δ -carbobenzoxy-L-ornithine methyl ester. For the selective reaction at the side chain under protection of the α-amino group of lysine, ornithine and (rather rarely) 1,4-diamino butyric acid in their copper complexes the following reagent were used: Ethylformate [17], acetic acid anhydride [14], phenylacetyl chloride [18], benzoyl chloride [6, 9c], carbobenzoxy chloride (benzyloxycarbonyl chloride, benzyl formic acid chloride) [14, 16, 19 -23], p-nitrobenzyl chloroformate [24], p-nitrophenyl-o-bromobenzyl carbonate [25], o-chlorobenzyl chloroformate [26], di-tertbutyl dicarbonate((Boc) 2 O) [27 -34] (which was introduced by Moroder and Wünsch [27]), tert-butylazidoformate (tert-butyloxycarbonylazide BocN 3 ) [35], tert-butyloxycarbonyl fluoride (BocF) [36], allyl chloroformate [37,38], p-(p -methoxyphenyl-azo)-benzyloxycarbonyl chloride (to give colored derivatives) [39], β ,β ,β -trichloro-ethyloxycarbonyl chloride [40], fluorenylmethoxycarbonyl azide (Fmoc-N 3 ) [41], biotin acid chloride [42], isonicotinyl-p-nitrophenyl carbonate [43], 2-(trimethylsilyl)ethyl-4-nitrophenyl carbonate [44].…”

Synthesis and Properties of [A19-(p-Fluorophenylalanine)] Insulin

“…Their purification was efficiently achieved by column chromatography on Sephadex LH-20. The Α-chain analogue was assembled from the protected segments [1][2][3][4][5][6][7][8][9][10][11][12] and [13][14][15][16][17][18][19][20][21]. A synthesis of the former segment [1][2][3][4][5][6][7][8][9][10][11][12] has been reported earlier ' 6] .…”

“…A synthesis of the former segment [1][2][3][4][5][6][7][8][9][10][11][12] has been reported earlier ' 6] . The C-terminal segment [13][14][15][16][17][18][19][20][21] was prepared from the intermediate segments [13][14][15], [16][17][18][19] and [20][21] as shown in Scheme 1. In the earlier synthesis this segment was assembled from [13][14][15][16], [17][18][19] and [20][21] [6J .…”

“…The C-terminal segment [13][14][15][16][17][18][19][20][21] was prepared from the intermediate segments [13][14][15], [16][17][18][19] and [20][21] as shown in Scheme 1. In the earlier synthesis this segment was assembled from [13][14][15][16], [17][18][19] and [20][21] [6J . This change in the synthetic scheme was done to enable the synthesis of the segment Bpoc-Leu-Glu(OBu f )--Asn-Phe(F)-OH (III, position [16][17][18][19] with a free C-terminal carboxyl function without resorting to alkaline saponification.…”