679788-76-2Relevant academic research and scientific papers
Selective esterifications of alcohols and phenols through carbodiimide couplings
Shelkov, Rimma,Nahmany, Moshe,Melman, Artem
, p. 397 - 401 (2007/10/03)
Esterification of carboxylic acids capable of forming ketene intermediates upon treatment with carbodiimides permits the selective acylation of alcohols in the presence of phenols lacking strong electron-withdrawing groups. The selectivity of acylations involving highly acidic phenols could be reversed through the addition of catalytic amount of acid. Esterification of other carboxylic acids was found to proceed through the formation of symmetric anhydrides and provide the opposite chemoselectivity. In both cases the relative acylation rates of substituted phenols are consistent with a reaction mechanism involving an attack of phenolate anions on electrophilic intermediates such as ketenes and symmetric anhydrides, with the carbodiimides serving both as an activating reagent and as a basic catalyst.
Barbituric acid derivatives, processes for their production and pharmaceutical agents containing these compounds
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, (2008/06/13)
PCT No. PCT/EP96/05766 Sec. 371 Date Aug. 26, 1998 Sec. 102(e) Date Aug. 26, 1998 PCT Filed Dec. 20, 1996 PCT Pub. No. WO97/23465 PCT Pub. Date Jul. 3, 1997Compounds of formula I, useful as matrix metalloprotease inhibitors, wherein X, Y and Z are each oxygen; R1 is selected from the group consisting of (a) n-octyl, (b) n-decyl, (c) biphenyl and (d) (4-phenoxy)phenyl, wherein the terminal monocycle for moieties (c)-(d) is unsubstituted or substituted by a substituent selected from the group consisting of -NH2, -NO2, -SO2NH2, -SO2CH3, acetyl, hydroxy, methoxy, ethoxy, cyano and halogen; R2 and R3 are each hydrogen; and R4 and R5, together with the nitrogen atom to which they are bound, form a piperazinyl or piperidyl ring, wherein the piperazinyl ring is substituted in the 4-position with a substituent selected from the group consisting of (a) a 6-membered aromatic monocycle having 0, 1 or 2 nitrogen atoms and the remainder of the atoms in the monocycle being carbon and (b) hydroxy-C1-C6 alkyl, wherein the monocycle is unsubstituted or substituted by a substituent selected from the group consisting of halogen, -NH2, -NO2, -SO2NH2, -SO2CH3, acetyl and cyano.
