Solid Supported Peptide Catalyst for the Synthesis of Flavanone and Azaflavanones

Sakirolla, Raghavendra; Lee, Yean Kee; Macharla, Venkataramana

doi:10.12723/mjs.49.3

Cited by 3 publications

(2 citation statements)

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“…Cyclization of 2'-aminochalcones (70) was also carried out using 0.3 equiv of solid support proline peptide to give azaflavanones (71) (Scheme 31). 56 The catalyst was removed by filtration and reused up to three times without any appreciable loss in catalytic activity.…”

Section: Cyclization Of 2'-aminochalcones Using Ionic Liquid or Prolinementioning

confidence: 99%

A review of the syntheses of flavanones, thioflavanones, and azaflavanones from 2'‐substituted chalcones

Lee

2021

Bulletin Korean Chem Soc

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Flavanones have been prepared by the cyclization of 2'-hydroxychalcones using acidic reagents, such as H 2 SO 4 , HX, CF 3 COOH, CH 3 SO 3 H, KF-celite, or SiO 2 . Treatment of 2'-hydroxychalcones with bases, such as LiOH, KOH, NaOAc, K 2 CO 3 , pyridine, Et 3 N, or N-methylimidazole afforded flavanones. The conversion of 2'-hydroxychalcones to flavanones has been conducted using Co(salpr), K 3 Fe (CN) 6 , CuO, or Ni(Tfacac) 2 . Thioflavanones have been prepared by deprotecting and cyclizing S-protected chalcones using AgNO 3 , HBr, CF 3 COOH, or NaOH and by adding NaSH or KCS 2 OEt to 2'-halochalcones and subsequent substitution. Azaflavanones have been prepared by cyclizing 2'-aminochalcones using acidic reagents, such as H 3 PO 4 , HCl, silica chloride, or K-10 clay. Furthermore, treatment of 2'-aminochalcones with Lewis acids, such as ZnCl 2 , SbCl 3 , Yb(OTf) 3 , InCl 3 , TaBr 5 , or CeCl 3 afforded azaflavanones, and chiral azaflavanones were prepared by cyclizing 2'-aminochalcones in the presence of per-6-ABCD, chiral amine, BINOL-phosphoric acid, or thiourea catalyst.

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Section: Cyclization Of 2'-aminochalcones Using Ionic Liquid or Prolinementioning

confidence: 99%

A review of the syntheses of flavanones, thioflavanones, and azaflavanones from 2'‐substituted chalcones

Lee

2021

Bulletin Korean Chem Soc

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“…[27][28][29][30][31] Flavanone structure is an important framework for the development of lead compounds with important biological activities, [32,33] whereby it has been intensively used for research and development during the last three decades, by synthetic and medicinal chemists. [34][35][36][37] Thus, a large number of methodologies considering the starting material for their obtention have been reported and they can be classified into four categories as follows (Scheme 1): 1) two steps Claisencyclization, [27,28,[38][39][40][41][42][43] 2) cyclization from chalcones, [3,4,[44][45][46][47][48] 3) one pot procedures starting from substituted benzaldehydes and 2hydroxyacetophenones [8,[49][50][51][52][53][54][55][56][57] and 4) Miscellaneous (a-d). [58][59][60] Among them, cyclization from chalcone (category 2) is the most used methodology.…”

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confidence: 99%