Conversion of diarylchalcones into 4,5-dihydropyrazole-1-carbothioamides: molecular and supramolecular structures of two precursors and three products

Mohammed A. E. Shaibah, Hemmige S. Yathirajan, Asma ., Nagaraja Manju, Balakrishna Kalluraya, Ravindranath S. Rathore, Christopher Glidewell

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Chalcones of type 4-XC6H4C(O)CH=CHC6H4(OCH2CCH)-4, where X = Cl, Br or MeO, have been converted to the corresponding 4,5-di­hydro­pyrazole-1-carbo­thio­amides using a cyclo­condensation reaction with thio­semicarbazide. The chalcones 1-(4-chloro­phen­yl)-3-[4-(prop-2-yn­yloxy)phen­yl]prop-2-en-1-one, C18H13ClO2, (I), and 1-(4-bromo­phen­yl)-3-[4-(prop-2-yn­yloxy)phen­yl]prop-2-en-1-one, C18H13BrO2, (II), are isomorphous, and their mol­ecules are linked into sheets by two independent C—Hπ(arene) inter­actions, both involving the same aryl ring with one C—H donor approaching each face. In each of the products (RS)-3-(4-chloro­phen­yl)-5-[4-(prop-2-yn­yloxy)phen­yl]-4,5-di­hydro­pyrazole-1-carbo­thio­amide, C19H16ClN3OS, (IV), (RS)-3-(4-bromo­phen­yl)-5-[4-(prop-2-yn­yloxy)phen­yl]-4,5-di­hydro­pyrazole-1-carbo­thio­amide, C19H16BrN3OS, (V), and (RS)-3-(4-meth­oxy­phen­yl)-5-[4-(prop-2-yn­yloxy)phen­yl]-4,5-di­hydro­pyrazole-1-carbo­thio­amide, C20H19N3O2S, (VI), the reduced pyrazole ring adopts an envelope conformation with the C atom bearing the 4-prop-2-yn­yloxy)phenyl substituent, which occupies the axial site, displaced from the plane of the four ring atoms. Compounds (IV) and (V) are isomorphous and their mol­ecules are linked into chains of edge-fused rings by a combination of N—H···S and C—H···S hydrogen bonds. The mol­ecules of (VI) are linked into sheets by a combination of N—H···S, N—H···N and C—H···π(arene) hydrogen bonds. Comparisons are made with the structures of some related compounds.
Original languageEnglish
Pages (from-to)360-365
Number of pages6
JournalActa Crystallographica Section E
Volume76
Issue number3
Early online date14 Feb 2020
DOIs
Publication statusPublished - Mar 2020

Keywords

  • Synthesis
  • Cyclocondensation
  • Chalcones
  • Heterocyclic compounds
  • Reduced pyrazoles
  • Crystal structures
  • Molecular conformation
  • Hydrogen bonding
  • Supramolecular assembly

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