3-(Benzothiazol-2-ylthio)- and 3-(Benzoxazol-2-ylthio)-1,2-benzisothiazole 1,1-Dioxides; New, Reactive Condensing Agents for the Synthesis of Amides and Esters
<i>N</i>,<i>N</i>′-Carbonyldi[2(3<i>H</i>)-benzoxazolethione]: New, Reactive Condensing Agent for the Synthesis of Amides, Esters, Peptides, and Polyamides
作者:Mitsuru Ueda、Naomi Kawaharasaki、Yoshio Imai
DOI:10.1246/bcsj.57.85
日期:1984.1
N′-carbonyldi[2(3H)-benzoxazolethione] (3), was readily prepared by the reaction of 2-benzoxazolethiol and trichloromethyl chloroformate in benzene. The condensing agent 3 is shown to be useful for the preparation of amides, esters, and dipeptides under mild conditions. A successful polyamide synthesis by the polycondensation of isophthalic acid with diamines using 3 is also described.
New activating agents, 3,3′-(phenylphosphinylidene)bis[2(3H)-benzoxazolone] (4) and 3,3′-(phenylphosphinylidene)bis[2(3H)-benzothiazolone] (5), were readily prepared by the reaction of phenylphosphonic dichloride (3) with 2(3H)-benzoxazolone (1) and 2(3H)-benzothiazolone (2) respectively in the presence of triethylamine at room temperature. The new activating agents 4 and 5 were found to be useful
2-benzisoxazol-3(2H)-one] (6), was readily prepared by the reaction of 1,2-benzisoxazol-3-ol and trichloromethyl chloroformate in toluene. The condensing agent 6 was shown to be very useful for the preparation of amides, esters, and dipeptides under mild conditions. A successful polyamide synthesis by one-pot polycondensation of isophthalic acid with diamines using 6 was also described.
Diphenyl (2,3-Dihydro-2-thioxo-3-benzoxazolyl)phosphonate: A New, Reactive Condensing Agent for the Synthesis of Amides, Esters, Peptides, and β-Lactams via Condensation
作者:Mitsuru Ueda、Hideharu Mori
DOI:10.1246/bcsj.65.1636
日期:1992.6
Diphenyl (2,3-dihydro-2-thioxo-3-benzoxazolyl)phosphonate (1) prepared from 2-benzoxazolethiol and diphenyl phosphorochloridate was proved to be a very useful condensing agent. A variety of amides, esters, and dipeptides were obtained in excellent yields. Furthermore, this reagent was successfully applied to the synthesis of β-lactams from β-amino acids.
One-pot ester and thioester formation mediated by pentafluoropyridine (PFP)
作者:Liam N. D. Beardmore、Steven L. Cobb、William D. G. Brittain
DOI:10.1039/d2ob01268e
日期:——
Acyl fluorides are valuable synthetic intermediates, but in some cases they can be challenging to handle and difficult to isolate given their susceptibility to degradation. In addition, many reagents utilised to prepare acyl fluorides are incompatible with in situ generation strategies and require the acyl fluoride to be isolated before any further reaction can take place. The combination of these