3754-51-6

Upstream product

• 1309972-81-3 3-(3-bromophenyl)-3-hydroxy-1-(2-hydroxyphenyl)propan-1-one 
• 3132-99-8 m-bromobenzoic aldehyde 
• 118-93-4 o-hydroxyacetophenone 
• 3754-50-5 3-(3-bromophenyl)-1-(2-hydroxyphenyl)prop-2-en-1-one 
• 491-38-3 1-benzopyran-4(4H)-one 
• 89598-96-9 (3-bromophenyl)boronic acid 
• 108440-17-1 (2E)-3-(3-bromophenyl)-1-(2-hydroxyphenyl)prop-2-en-1-one 

Downstream Products

• 108440-17-1 (2E)-3-(3-bromophenyl)-1-(2-hydroxyphenyl)prop-2-en-1-one 
• 3754-53-8 3'-Bromoflavone 

Relevant academic research and scientific papers

Stereoselective reduction of flavanones by marine-derived fungi

Biotransformation is an alternative with great potential to modify the structures of natural and synthetic flavonoids. Therefore, the bioreduction of synthetic halogenated flavanones employing marine-derived fungi was described, aiming the synthesis of flavan-4-ols 3a-g with high enantiomeric excesses (ee) of both cis- and trans-diastereoisomers (up to >99% ee). Ten strains were screened for reduction of flavanone 2a in liquid medium and in phosphate buffer solution. The most selective strains Cladosporium sp. CBMAI 1237 and Acremonium sp. CBMAI1676 were employed for reduction of flavanones 2a-g. The fungus Cladosporium sp. CBMAI 1237 presented yields of 72–87% with 0–64% ee cis and 0–30% ee trans with diastereoisomeric ratio (dr) from 52:48 to 64:36 (cis:trans). Whereas Acremonium sp. CBMAI 1676 resulted in 31% yield with 77–99% ee of the cis and 95–99% ee of the trans-diastereoisomers 3a-g with a dr from 54:46 to 96:4 (cis:trans). To our knowledge, this is the first report of the brominated flavon-4-ols 3e and 3f. The use of fungi, with emphasis for these marine-derived strains, is an interesting approach for enantioselective reduction of halogenated flavanones. Therefore, this strategy can be explored to obtain enantioenriched compounds with biological activities.

Palladium-catalyzed asymmetric conjugate addition of arylboronic acids to heterocyclic acceptors

Flava Flavanone: Asymmetric conjugate additions to chromones and 4-quinolones are reported utilizing a single catalyst system formed in situ from Pd(OCOCF3)2 and (S)-tBuPyOX. Notably, these reactions are performed in wet solvent under ambient atmosphere, and employ readily available arylboronic acids as the nucleophile, thus providing ready access to these asymmetric heterocycles (see scheme).

Synthesis of chiral flavanones from tricarbonyl (η6- Arylbenzaldehyde)chromium(0)

A synthesis of chiral flavanones via the condensation of tricarbonyl(η6-arylbenzaldehyde)chromium(0) and o-hydroxyacetophenone in a shorter time at room temperature have been developed. The tricarbonylchromium(0) group was removed by virtue of light and the enantioenriched flavanones was formed with highly enantioselectivity (> 95 % ee).

Synthetic approach to flavanones and flavones via ligand-free palladium(ii)-catalyzed conjugate addition of arylboronic acids to chromones

The remarkable catalytic effects of Fe(OTf)3 in the context of the Pd(ii)-catalyzed conjugate addition of arylboronic acids to chromones were observed to yield a variety of flavanones under mild conditions. The addition of catalytic amounts of DDQ and KNO2 to the reactions exclusively yielded flavone analogs. The reaction scope for the transformation was fairly broad, affording good yields of a wide range of flavanones and flavones, which are privileged structures in many biologically active compounds.

Environmentally benign syntheses of flavanones

Mild and environmentally benign methods for the syntheses of flavanones are described. The reaction of o-hydroxyacetophenones (1) and benzaldehydes (2) in water in the presence of DABCO at room temperature gave 3-hydroxy-1-(2- hydroxylphenyl)-3-arylpropan-1-ones (3a-i) as intermediates. Followed by an intramolecular dehydration of the 3a-i with the modified Mitsunobu's reaction, the target flavanones (4a-i) were obtained. Moreover, the reaction of 1 and 2 at the same conditions but at reflux gave flavanones in one pot with good yields.

Thermal Isomerization Equilibrium between 2'-Hydroxychalcones and Flavanones

Nine substituted 2'-hydroxychalcones and the corresponding flavanones were heated separately at 230 +/- 0.2 deg C in nitrogen atmosphere.Both materials were mutually isomerized under these reaction conditions and the equilibrium constants of this isomerization were measured by means of HPLC analyses.The substituent effect on the equilibrium is discussed and thermodynamic functions (ΔG, ΔH, and ΔS) are calculated.