Efficient synthesis of α,β-dichlorinated ketones from α,β-dichlorinated Weinreb amides through a simple work-up procedure

Prakoso, Nurcahyo Iman; Matsuda, Fuyuhiko; Umezawa, Taiki

doi:10.1039/d1ob01379c

Cited by 7 publications

(1 citation statement)

References 30 publications

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“…Prior to the synthesis of the derivatives of 1 , we have achieved convergent total synthesis of (+)‐ 1 from optically active epoxide 6 via Wittig reaction (C1‐7 installation) followed by allylic substitution reaction (C18‐22) with Grignard reagent and copper catalyst [37] to reveal that both enantiomers of 1 show the similar toxicity against brine shrimp, indicating small effect of the absolute configurations of 1 toward the biological activity (Scheme 1). [38–40] In order to obtain more information about the biological activities, the preparations of three derivatives 10 – 12 were next planed by modification of reaction conditions at the late stage of the total synthesis (Figure 2). Tetrachloride derivative 10 , lack of chlorides at C15 and C16, is expected to have similar biological activities to 1 because Okino has demonstrated that congeners of 1 , such as A and B , containing less chlorides maintained the biological activities [28] .…”

Section: Introductionmentioning

confidence: 99%

Syntheses and Biological Activities of Danicalipin A Derivatives

Umezawa

Maeda

Akiyama

et al. 2023

Chemistry & Biodiversity

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Synthesis of three derivatives of danicalipin A, tetrachloride, trisulfate and a fluorescent probe was achieved through Wittig reaction strategy. Toxicity of the derivatives against brine shrimp (Artemia salina) as also investigated to provide useful information for the biological activity; i) less chloride derivative showed similar toxicity to danicalipin A, ii) the amphiphilic property, a characteristic feature of danicalipin A, was crucial because trisulfate considerably decreased the toxicity and iii) fluorescent derivative kept brine shrimp toxicity of danicalipin A.

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Section: Introductionmentioning

confidence: 99%

Syntheses and Biological Activities of Danicalipin A Derivatives

Umezawa

Maeda

Akiyama

et al. 2023

Chemistry & Biodiversity

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Synthesis and Conformational Analysis of α,β‐Dichlorocarbonyl Compounds

Kobayashi,

Prakoso,

Zheng

et al. 2024

Eur J Org Chem

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α,β‐Dichlorocarbonyl compounds were synthesized by facile dichlorination of α,β‐unsaturated amides with TCIA‐PPh3 and the resultant amides were converted to ketones. Conformational analyses of the products were performed to confirm our previous hypothesis regarding vicinal dichlorinated carbonyl compounds. The compounds exhibited 1H NMR signals with large coupling constants (7‐11 Hz) for the 1,2‐anti‐configuration and small coupling constants (3‐4 Hz) for the 1,2‐syn‐configuration. The syn‐pentane interaction enabled rational conformational analysis of the α,β‐dichlorinated carbonyl compounds, although some interesting exceptions were observed. Consideration of these conformations is helpful in assigning relative configurations of α,β‐dihalogenated carbonyl compounds in general.

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Methyltrimethoxysilane (MTM) as a Reagent for Direct Amidation of Carboxylic Acids

2022

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Methyltrimethoxysilane [MTM, CH 3 Si(OMe) 3 ] has been demonstrated to be an effective, inexpensive, and safe reagent for the direct amidation of carboxylic acids with amines. Two simple workup procedures that provide the pure amide product without the need for further purification have been developed. The first employs an aqueous base-mediated annihilation of MTM. The second involves simple product crystallization from the reaction mixture providing a low process mass intensity direct amidation protocol.

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Efficient synthesis of α,β-dichlorinated ketones from α,β-dichlorinated Weinreb amides through a simple work-up procedure

Abstract: An efficient synthesis of α,β-dichlorinated ketones from α,β-dichlorinated Weinreb amides is described. Quenching with nonaqueous HCl avoided side reactions. A novel reactivity of the Weinreb amide is also discussed.

Cited by 7 publications

References 30 publications

Syntheses and Biological Activities of Danicalipin A Derivatives

Syntheses and Biological Activities of Danicalipin A Derivatives

Synthesis and Conformational Analysis of α,β‐Dichlorocarbonyl Compounds

Methyltrimethoxysilane (MTM) as a Reagent for Direct Amidation of Carboxylic Acids

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