Amino-acids and peptides. Part 41. An examination of some new amino-protecting groups

Protected Amino Acids in Peptide Synthesis

“…THF (pH 4.2, 30 min, 86%, or pH 5.5-7.2, 18h, 96%) [125]; -1.70V, O.1M LiCI0 4 , (85%) [126,127]. Reported cleavage conditions are: catalytic hydrogenolysis in acetic acid; electrolysis (200 rnA [131,132]. Lys(Troc)] might also be cleaved by catalytic hydrogenolysis [128].…”

Novel Conversion of 4-Aminoquinolines to New Tricyclic (<i>R,S</i>)-3-Methylazeto[3,2-<i>c</i>] Quinolin-2(2a<i>H</i>)-Ones and Versatile One Step Synthesis of <i>N</i>-(Quinolin-4-yl) Carbamates from 4-Aminoquinolines

“…This strategy was later utilized to prepare biologically active compounds including: 1) pyridyl urea analogues as cardioselective anti-ischemic ATP-sensitive potassium channel openers; 2) N-(ureidoalkyl)-benzyl-piperidines as potent CC chemokine receptor-3 (CCR-3) antagonists; 7,8 and 3) anticancer nitrogen mustard prodrugs linked glutamic acid residue via a urea or carbamate spacer for antibody-directed enzyme prodrug therapy (ADEPT). [9][10][11][12] Previous studies also revealed that reaction of 1 with 2-, 3-, or 4-aminopyridine (10) afforded corresponding pyridin-2-, 3-, or 4-yl carbamic acid 4-nitrophenyl ester (11). 7,8 While reaction of 1 or 3,4,5-trichlorophenyl chloroformate with di-2-pyridylmethanol (12) resulted in the formation of 5-(2′-pyridyl)pyrido [1,2-c]oxazol-2-one (13) via N-acylation followed by intramolecular cyclization.…”

“…[9][10][11][12] Previous studies also revealed that reaction of 1 with 2-, 3-, or 4-aminopyridine (10) afforded corresponding pyridin-2-, 3-, or 4-yl carbamic acid 4-nitrophenyl ester (11). 7,8 While reaction of 1 or 3,4,5-trichlorophenyl chloroformate with di-2-pyridylmethanol (12) resulted in the formation of 5-(2′-pyridyl)pyrido [1,2-c]oxazol-2-one (13) via N-acylation followed by intramolecular cyclization. 13 On the other hand, Devraj et al 14 reported that reaction of naturally occurring anticancer ellipticine (14) with 1 followed by in situ reduction of the Nacylated intermediate gave 2-acyl-1,2-dihydroellipticine (15).…”

Novel Conversion of 4-Aminoquinolines to New Tricyclic (<i>R,S</i>)-3-Methylazeto[3,2-<i>c</i>] Quinolin-2(2a<i>H</i>)-Ones and Versatile One Step Synthesis of <i>N</i>-(Quinolin-4-yl) Carbamates from 4-Aminoquinolines

“…[9][10][11][12] Previous studies also revealed that reaction of 1 with 2-, 3-, or 4-aminopyridine (10) afforded corresponding pyridin-2-, 3-, or 4-yl carbamic acid 4-nitrophenyl ester (11). 7,8 While reaction of 1 or 3,4,5-trichlorophenyl chloroformate with di-2-pyridylmethanol (12) resulted in the formation of 5-(2′-pyridyl)pyrido[1,2-c]oxazol-2-one (13) via N-acylation followed by intramolecular cyclization.…”