Directorate of Drug Substance Development

Budapest, Hungary

Directorate of Drug Substance Development

Budapest, Hungary
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Bertha F.,Directorate of Drug Substance Development | Kegl T.,University of Pécs | Fetter J.,Budapest University of Technology and Economics | Molnar B.,Directorate of Drug Substance Development | And 4 more authors.
Journal of Organic Chemistry | Year: 2017

When refluxing with sodium hydrogen carbonate in acetonitrile, 7-chloro-5-(4-fluorophenyl)-1,3-dihydro-2,3,4-benzothiadiazepine 2,2-dioxide afforded, after loss of dinitrogen and subsequent ring contraction, the corresponding sulfone in 83% yield. Similar treatment of the related thiadiazolo-fused tricycles, i.e. 9-aryl-5H,7H-[1,2,5]thiadiazolo[3,4-h][2,3,4]benzothiadiazepine 6,6-dioxides, resulted in a substantially different product mixture: formation of sultines and benzocyclobutenes was observed, while only small amounts of the sulfones were formed, if any. Density functional theory calculations support the mechanism proposed for the transformations involving a zwitterionic intermediate formed by the tautomerization of the thiadiazepine ring followed by dinitrogen extrusion. When starting from 7-chloro-substituted 2,3,4-benzothiadiazepine 2,2-dioxide, the formation of sulfone via o-quinodimethane is the preferred pathway from the zwitterion. However, in the case of thiadiazolobenzothiadiazepine 6,6-dioxides it has been found that the ring closure of the zwitterion leading to the formation of sultines was kinetically preferred over the loss of sulfur dioxide leading to o-quinodimethane, which is the key intermediate to benzocyclobutene-type products. The calculations explain the differences observed between the product distributions of the chloro-substituted and the thiadiazolo-fused derivatives. © 2017 American Chemical Society.


Kokai E.,Budapest University of Technology and Economics | Nagy J.,Budapest University of Technology and Economics | Toth T.,Budapest University of Technology and Economics | Kupai J.,Budapest University of Technology and Economics | And 3 more authors.
Monatshefte fur Chemie | Year: 2016

Abstract: A new synthetic route was elaborated at our laboratory providing a convenient access to 5,7-dihydro-6H-pyrrolo[2,3-d]pyrimidin-6-ones (diazaoxindoles), a compound family of biological relevance. Treatment of the easily available ethyl 2-(4-chloropyrimidin-5-yl)acetate derivatives with ammonia afforded the corresponding 2-(4-aminopyrimidin-5-yl)acetamides, which were finally cyclized to the target compounds. Graphical abstract: [Figure not available: see fulltext.] © 2016 Springer-Verlag Wien


PubMed | Budapest University of Technology and Economics and Directorate of Drug Substance Development
Type: Journal Article | Journal: Molecules (Basel, Switzerland) | Year: 2016

The paper provides a comprehensive review of the base-catalysed C3-alkylation of N-unprotected-3-monosubstituted oxindoles. Based on a few, non-systematic studies described in the literature using butyllithium as the deprotonating agent, an optimized method has now been elaborated, via the corresponding lithium salt, for the selective C3-alkylation of this family of compounds. The optimal excess of butyllithium and alkylating agent, and the role of the halogen atom in the latter (alkyl bromides vs. iodides) were also studied. The alkylation protocol has also been extended to some derivatives substituted at the aromatic ring. Finally, various substituents were introduced into the aromatic ring of the N-unprotected 3,3-dialkyloxindoles obtained by this optimized method.

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