1275576-89-0Relevant articles and documents
New spiro (thio) barbiturates based on cyclohexanone and bicyclo [3.1.1]heptan-6-one by nonconcerted [1+5] cyclo addition reaction and their conformational structures
Pesyan, Nader Noroozi,Noori, Sirons,Poorhassan, Soodabeh,ahin, Ertan
, p. 423 - 440 (2014)
Crossed-aldol condensation reaction of aromatic aldehydes with ketones such as; acetone and cyclohexanone leads to the efficient formation of cross conjugated α,β-unsaturated ketones in excellent yield. The intermolecular and then intramolecular Michael addition reaction of α,β-unsaturated ketones derived from acetone and cyclohexanone with (thio)barbituric acids lead to synthesis new type of 7,11-diaryl-2,4-diazaspiro[5.5]undecane-1,3,5,9-tetraone and 2,4-diaryl-1'H-spiro[bicyclo[3.3.l]nonane-3,5'-pyrimidine]-2',4',6',9(3'H)-tetraone, respectively in good yield. Structure elucidation is carried out by 1H NMR, 13C NMR, FT-IR, UV-Visible, mass spectroscopy and X-ray crystallography techniques. A possible mechanism of the formation is discussed. The structural conformation also demonstrated by coupling constants derived from dihedral angles between vicinal and geminal protons. The 1H NMR spectra of NH protons of spiro compounds derived from barbituric acid show a broad singlet peak instead, these protons in the spiro compounds derived from thiobarbituric acid show two distinct peaks.
Lewis acid mediated diastereoselective synthesis of fused fluorinated spiroketal as potential biologically active compounds
Agbaje, Oluropo C.,Fadeyi, Olugbeminiyi O.,Okoro, Cosmas O.
scheme or table, p. 5297 - 5300 (2011/10/30)
A series of substituted dibenzalacetones prepared using standard procedures were condensed with 5-methyl, 5-phenyl, and 5-trifluoromethyl-1,3- cyclohexanediones respectively, in toluene containing BF3·OEt as the Lewis acid catalyst. The reaction was found to be highly diastereoselective (dr, 9:1). The resulting spiroketals 1a-r were formed in moderate to good yields. In addition, a synthetically and biologically useful by-product identified as chromenone 7 was observed.
