487-25-2Relevant articles and documents
Transfer Hydrogenation of Flavanones and ortho-Hydroxychalcones to 1,3-Diarylpropanols Catalyzed by CNN Pincer Ruthenium Complexes
Soto, Martín,Gotor-Fernández, Vicente,Rodríguez-Solla, Humberto,Baratta, Walter
, p. 2152 - 2157 (2021/03/03)
The transfer hydrogenation of flavanones and ortho-hydroxychalcones catalyzed by ruthenium pincer complexes RuCl(CNNPh)(disphosphine) has allowed the synthesis of ortho-hydroxy 1,3-diarypropanols in 80–88 % yield, under mild reaction conditions and short reaction times (1 h) in 2-propanol. The amount of the co-catalyst NaOiPr has been found crucial for the selective reduction of flavanones to ortho-hydroxy 1,3-diarypropanols vs. flavan-4-ols. Preliminary results show that with pincer catalysts bearing (S,R)-Josiphos, flavanone is reduced to the corresponding (S)-alcohol in moderate conversion (36 %) and up to 92 % ee.
B regioselective and chemoselective biotransformation of 2′-hydroxychalcone derivatives by marine-derived fungi
Nitschke, Marcia,Porto, André Luiz Meleiro,de Matos, Iara Lisboa
, (2021/08/06)
Eight fungal strains (Penicillium raistrickii CBMAI 931, Cladosporium sp. CBMAI 1237, Aspergillus sydowii CBMAI 935, Penicillium oxalicum CBMAI 1996, Penicillium citrinum CBMAI 1186, Mucor racemosus CBMAI 847, Westerdykella sp. CBMAI 1679, and Aspergillus sclerotiorum CBMAI 849) mediated the biotransformation of the 2′-hydroxychalcone 1a. The main products obtained were from hydrogenation, hydroxylation, and cyclization reactions. Penicillium raistrickii CBMAI 931 catalyzed the chemoselective reduction of 1a to produce 2′-hydroxydihydrochalcone 2a (72%) in 7 days of incubation in phosphate buffer (pH 7). Aspergillus sydowii CBMAI 935 promoted the hydroxylation of 1a to yield 2′,4-dihydroxy-dihydrochalcone 5a (c = 42%) in 7 days of incubation in phosphate buffer (pH 8). The reaction using P. citrinum CBMAI 1186 and M. racemosus CBMAI 847 presented main cyclization products in phosphate buffer (pH 8), but the reactions with these fungi did not present enantioselectivity. Marine-derived fungi were effective and versatile biocatalysts for biotransformation of the 2′-hydroxychalcones yielding different products according to the conditions and microorganism used.
Oxygen mediated highly efficient cobalt(ii) porphyrin-catalyzed reduction of functional chromones: experimental and computational studies
Poonam,Kumari, Pratibha,Grishina, Maria,Potemkin, Vladimir,Verma, Abhishek,Rathi, Brijesh
, p. 5228 - 5238 (2019/03/29)
The highly efficient oxygen mediated reduction of functional chromones with sodium borohydride (NaBH4) catalyzed by cobalt(ii) porphyrins afforded biologically active chroman-4-ols as the reduction products in 80-98% yields. Oxygen assists in the formation of hydridocobalt(iii) porphyrin as a key intermediate, which releases hydride rapidly to reduce the chromones. Additionally, the correlation between quantum calculation results of the catalysts' conversions, yields, times and logarithms of the rate constants for the oxygen assisted reduction reaction was studied. The mechanism of the reaction was also justified by establishing a quantitative relationship between the rate constant, the α-HOMO orbital of the catalytic complex and the stabilization energy of the complex with oxygen.
