A concise synthesis of chiral 2-methyl chroman-4-ones : Stereo selective build-up of the chromanol moiety of anti-HIV agent calanolide A

Rao, A. V. Rama; Gaitonde, A. S.; Prakash, K. R. C.; Rao, S. P.

doi:10.1016/s0040-4039(00)73429-0

Cited by 48 publications

(9 citation statements)

References 12 publications

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“…Perkin condensation of 2,4‐dihydroxybenzaldehyde and 4‐methoxyphenylacetic acid in a mixture of pyridine and acetic anhydride gave derivative 8 , which was deacetylated under basic conditions resulting in 9 . Methyl ( S )‐(−)‐lactate was now coupled to 9 using the Mitsunobu protocol to retain the chiral information via Mitsunobu inversion . In contrast to the two aforementioned Mitsunobu reactions, di‐ tert ‐butyl azodicarboxylate was used, because the previously used DIAD furnished diisopropyl hydrazine‐1,2‐dicarboxylate, which could not be separated from the product of this reaction.…”

Section: Resultsmentioning

confidence: 99%

“…Methyl (S)-(À)-lactate was now coupled to 9 using the Mitsunobu protocol to retain the chiral information via Mitsunobu inversion. 32 In contrast to the two aforementioned Mitsunobu reactions, di-tert-butyl azodicarboxylate was used, because the previously used DIAD furnished diisopropyl hydrazine-1,2-dicarboxylate, which could not be separated from the product of this reaction. Alkaline hydrolysis of 10 gave the free carboxylic acid 11, suitable for coupling to different chiral amines after activation.…”

Section: Resultsmentioning

confidence: 99%

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Synthesis and Evaluation of Two Coumarin‐Type Derivatization Reagents for Fluorescence Detection of Chiral Amines and Chiral Carboxylic Acids

Mertens

Gütschow

2013

Chirality

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The synthesis of two fluorescent coumarin-type chiral derivatization agents (4 and 11) is reported. A chiral side chain was introduced at position 7 of the coumarin via Mitsunobu reaction. The two coumarins bear in this side chain either a free amino group or a carboxyl group, making them useful for further transformations. Conjugates of chiral prototype drugs with 4 or 11 were prepared by amide coupling of the analyte's carboxyl group to the reagent's amine group, or vice versa. The separation of seven diastereomeric conjugates through achiral high-performance liquid chromatography (HPLC) on a common C18 column is demonstrated.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Synthesis and Evaluation of Two Coumarin‐Type Derivatization Reagents for Fluorescence Detection of Chiral Amines and Chiral Carboxylic Acids

Mertens

Gütschow

2013

Chirality

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“…In the 1 H NMR spectrum, 3-benzoyl-flavanones characteristically display two doublet resonances corresponding to the methine hydrogens present at the dihydropyranone ring (~5.17 ppm and 6.02 ppm, respectively). Rao et al described the synthesis of both cis and trans 7-methoxy-2,3-dimethylchroman-4-one and showed that the coupling constant for the cis compound to be approximately 3.4 Hz and the trans being larger around 11.5 Hz [14]. The trans configuration was, therefore, attributed to compounds 2a-z based on comparison of their coupling constants with similar compounds in the literature given that the coupling constant for 3-benzoyl-flavanones was 12 Hz.…”

Section: Synthesis Of 3-benzoyl Flavanonesmentioning

confidence: 99%

Trypanocidal Activity of Flavanone Derivatives

et al. 2020

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Chagas disease, also known as American trypanosomiasis, is classified as a neglected disease by the World Health Organization. For clinical treatment, only two drugs have been on the market, Benznidazole and Nifurtimox, both of which are recommended for use in the acute phase but present low cure rates in the chronic phase. Furthermore, strong side effects may result in discontinuation of this treatment. Faced with this situation, we report the synthesis and trypanocidal activity of 3-benzoyl-flavanones. Novel 3-benzoyl-flavanone derivatives were prepared in satisfactory yields in the 3-step synthetic procedure. According to recommended guidelines, the whole cell-based screening methodology was utilized that allowed for the simultaneous use of both parasite forms responsible for human infection. The majority of the tested compounds displayed promising anti-Trypanosoma cruzi activity and the most potent flavanone bearing a nitrofuran moiety was more potent than the reference drug, Benznidazole.

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“…[58] (This compound was later methylated for analytical purposes.) In the intermolecular version of this reaction, phloroglucinol ( 52 ) and ( S )-3-hydroxybutyronitrile ( 53 ) were subjected to Houben–Hoesch conditions, which generated chromanone 54 .…”

Section: Carbon–heteroatom Bond Formationmentioning

confidence: 99%

“…[35b,36,38,46,58] In their synthesis, Noda and Watanabe generated dithiane 59 , which was lithiated with n BuLi and added to either ( S )- or ( R )-styrene oxide to generate diol 60 (Scheme 28). [62] Finally, Mitsunobu inversion and desulfurization generated the enantio-enriched flavanone.…”

Section: Carbon–heteroatom Bond Formationmentioning

confidence: 99%

Asymmetric Methods for the Synthesis of Flavanones, Chromanones, and Azaflavanones

2011

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Flavanones, chromanones, and related structures are privileged natural products that display a wide variety of biological activities. Although flavanoids are abundant in nature, there are a limited number of available general and efficient synthetic methods for accessing molecules of this class in a stereoselective manner. Their structurally simple architectures belie the difficulties involved in installation and maintenance of the stereogenic configuration at the C2 position, which can be sensitive and can undergo epimerization under mildly acidic, basic, and thermal reaction conditions. This review presents the methods currently used to access these related structures. The synthetic methods include manipulation of the flavone/flavanone core, carbon-carbon bond formation, and carbon–heteroatom bond formation.

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A concise synthesis of chiral 2-methyl chroman-4-ones : Stereo selective build-up of the chromanol moiety of anti-HIV agent calanolide A

Cited by 48 publications

References 12 publications

Synthesis and Evaluation of Two Coumarin‐Type Derivatization Reagents for Fluorescence Detection of Chiral Amines and Chiral Carboxylic Acids

Synthesis and Evaluation of Two Coumarin‐Type Derivatization Reagents for Fluorescence Detection of Chiral Amines and Chiral Carboxylic Acids

Trypanocidal Activity of Flavanone Derivatives

Asymmetric Methods for the Synthesis of Flavanones, Chromanones, and Azaflavanones

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