81712-02-9Relevant academic research and scientific papers
2-HALOVINYL ARYL SULFONES: NEW COUPLING REAGENTS FOR CARBOXAMIDE FORMATION
Shimagaki, Masayuki,Koshiji, Hiroko,Oishi, Takeshi
, p. 45 - 58 (2007/10/02)
E-2-Chlorovinyl p-nitrophenyl sulfone 6 and 2-bromo-2-trifluoromethylvinyl phenyl sulfone 7a reacted with carboxylic acids in the presence of a molar equiv of Et3N affording the corresponding 2-acyloxyvinyl sulfones 8, 11, 17, 18, 22, 25, 28 and 29.The latter, on treatment with amines, gave amides 9, 13, 19, 23 and 26 and peptides 30 and 32.These reagents 6 and 7a were also used for the formation of N-methylanilides 13d, 13e, 19d, 23 and 26.Particularly, 6 was successfully used for synthesis of a macrocyclic lactam 23 involving a N-methylanilide moiety.The amidation reac tions proceeded under essentially neutral conditions.Therefore, base-sensitive β-hydroxycarboxy-N-methylanilides such as 26, whose structural unit was involved in maytansine 5, could be prepared by the present method.The reagent 6 was also effective for the preparation of peptides such as Val-N-MeVal derivatives (e.g.32), which were difficult to prepare by other methods.
A NEW EFFICIENT COUPLING REAGENT FOR CYCLIC N-METHYLANILIDE FORMATION
Shigamaki, Masayuki,Koshiji, Hiroko,Oishi, Takeshi
, p. 49 - 52 (2007/10/02)
Treatment of the reagent (5) with the amino acid (11) in DMF afforded the active ester (12), which was added slowly to toluene at 95-100 deg C to produce the 15-membered cyclic N-methylanilide (13).The reaction proceeds under essentially neutral condition
