21282-65-5Relevant academic research and scientific papers
Aromatic 2-(thio)ureidocarboxylic acids as a new family of modulators of multidrug resistance-associated protein 1: Synthesis, biological evaluation, and structure - Activity relationships
H?cker, Hans-Georg,Leyers, Stefan,Wiendlocha, Jeanette,Gütschow, Michael,Wiese, Michael
supporting information; experimental part, p. 4586 - 4595 (2010/03/03)
Four series of aromatic carboxylic acids were prepared with a urea or thiourea moiety at the neighboring position to the carboxyl group and benzene or thiophene as aromatic scaffold. Using a calcein AM assay, these compounds were evaluated as inhibitors o
One-Pot Reactions of N-(Mesyloxy)phthalimides with Secondary Amines to 2-Ureidobenzamides, 2-Ureidobenzoic Acids, Ethyl 2-Ureidobenzoates, or Isatoic Anhydrides
Guetschow, Michael
, p. 5109 - 5115 (2007/10/03)
The reaction of N-(mesyloxy)phthalimides with secondary amines was examined. Transformations are accomplished by one-pot reactions to optionally afford corresponding 2-ureidobenzamides, 2-ureidobenzoic acids, ethyl 2-ureidobenzoates, or isatoic anhydrides, respectively. The mechanism of the acid-catalyzed hydrolysis (or alcoholysis) of intermediate 2-ureidobenzamides to 2-ureidobenzoic acids (or esters) is discussed. A proton transfer mechanism involving the ureido moiety as an internal acid catalyst is proposed. Intermediate 2-ureidobenzoic acids undergo a further transformation to isatoic anhydrides. The utilization of the obtained 2-ureidobenzamides, 2-ureidobenzoic acids, and ethyl 2-ureidobenzoates to prepare 3,1-benzoxazin-4-ones is demonstrated.
3,1-Benzothiazin-4-ones and 3,1-benzoxazin-4-ones: Highly different activities in chymotrypsin inactivation
Neumann,Guetschow
, p. 72 - 88 (2007/10/02)
3,1-Benzothiazin-4-ones are sulfur analogs of the potent serine protease inactivators of the 3,1-benzoxazin-4-one type, which acylate the serine residue within the active site of the enzymes. A series of 2-amino-3,1-benzothiazinones was synthesized, but these compounds showed only very little inhibitory activity toward chymotrypsin, a model serine protease. Detailed investigations revealed that benzothiazinones and benzoxazinones react with identical mechanisms, but benzothiazinones acylate chymotrypsin with much lower rate constants. Investigations of nonenzymatic hydrolysis showed the benzothiazinones to be intrinsically more stable than benzoxazinones. It was concluded from spectroscopic results, that benzoxazinones are highly activated due to the absence of ester-like resonance. 2-Benzoylamino-4H-3,1-benzoxazin-4-one was found to be a new, highly active chymotrypsin inactivator. In contrast, benzothiazinones were found to be resonance stabilized. The contribution of a resonance structure with an exocyclic oxanion to the overall structure of the benzothiazinones and its nonproductive binding to the active site explained their low reactivity toward chymotrypsin.
