Assembling of medium/long chain-based β-arylated unnatural amino acid derivatives via the Pd(II)-catalyzed sp3 β-C-H arylation and a short route for rolipram-type derivatives

Tomar, Radha; Bhattacharya, Debabrata; Babu, Srinivasarao Arulananda

doi:10.1016/j.tet.2019.03.018

Cited by 17 publications

(15 citation statements)

References 95 publications

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“…Unhindered, linear, aliphatic substrates with alkyl, (hetero)aryl, amine, alcohol and (thio)ether substituents generally afford good hydrolysis/alcoholysis yields ( 19 – 30 , Scheme 4 Ci), [14, 28–36] however certain functional groups are incompatible with strongly Brønsted acidic/basic conditions (see also Scheme 7). For instance, phthaloyl protecting groups are hydrolyzed concomitantly with the AQ directing group ( 20 ) [29] .…”

Section: Nucleophilic Cleavage Of the Amide Bondmentioning

confidence: 99%

“…For instance, phthaloyl protecting groups are hydrolyzed concomitantly with the AQ directing group ( 20 ) [29] . Alcoholysis conditions can be slightly more compatible ( 21 ), [30] and Lewis acidic (see Section 1.2.1) or oxidative CAN conditions (see Section 2.2) can offer a milder alternative to preserve some of these functionalities.…”

Section: Nucleophilic Cleavage Of the Amide Bondmentioning

confidence: 99%

“…Carbamate 102 reacts with ethylamine to give a free phenol ( 103 ) after cleavage of the auxiliary [52] . The proximity effect of intramolecular nucleophilic functional groups discussed above can also be exploited to facilitate AQ transamidation to yield β‐ and γ‐lactams, albeit under relatively forcing conditions ( 106 , 108 – 112 ) [30, 77] . Notably, AQ‐amide 105 is activated towards nucleophilic attack of the pendant amine by addition of a Lewis acid—further examples of this type of reactivity are discussed in the next section.…”

Section: Nucleophilic Cleavage Of the Amide Bondmentioning

confidence: 99%

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A Guide to Directing Group Removal: 8‐Aminoquinoline

Fitzgerald

O’Duill

2021

Chemistry A European J

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The use of directing groups allows high levels of selectivity to be achieved in transition metal‐catalyzed transformations. Efficient removal of these auxiliaries after successful functionalization, however, can be very challenging. This review provides a critical overview of strategies used for removal of Daugulis’ 8‐aminoquinoline (2005–2020), one of the most widely used N,N‐bidentate directing groups. The limitations of these strategies are discussed and alternative approaches are suggested for challenging substrates. Our aim is to provide a comprehensive end‐users’ guide for chemists in academia and industry who want to harness the synthetic power of directing groups—and be able to remove them from their final products.

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Section: Nucleophilic Cleavage Of the Amide Bondmentioning

confidence: 99%

Section: Nucleophilic Cleavage Of the Amide Bondmentioning

confidence: 99%

Section: Nucleophilic Cleavage Of the Amide Bondmentioning

confidence: 99%

See 1 more Smart Citation

A Guide to Directing Group Removal: 8‐Aminoquinoline

Fitzgerald

O’Duill

2021

Chemistry A European J

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“…Of particular interest, Daugulis, [13a] Qin, [15a,b] Bach, [15c] and Babu [15d] have independently reported examples of Pd(II)‐catalyzed, 8‐aminoquinoline‐directed arylation of the β ‐C(sp 3 )−H bonds of various short/medium/long chain‐based amino alkanoic acid derivatives 3 (Scheme 2). In our earlier paper, [15d] we reported some synthetic transformations with the newly assembled β ‐C−H arylated N ‐(quinolin‐8‐yl)butanamides ( 4′ , γ ‐aminobutyric acid derivatives). Accordingly, we reported a short route for assembling rolipram, its analogues ( 2 i ) and 3‐arylated GABA derivatives such as baclofen, phenibut and tolibut.…”

Section: Introductionmentioning

confidence: 99%

Direct Lactamization of β‐Arylated δ‐Aminopentanoic Acid Carboxamides: En Route to 4‐aryl‐2‐Piperidones, Piperidines, Antituberculosis Molecule Q203 (Telacebec) and its Analogues

2022

Self Cite

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We report the synthesis of 4-aryl-2-piperidone, 4arylpiperidine motifs, antituberculosis molecule Q203 (Telacebec) and its analogues. Direct lactamization of β-CÀ H arylated N-phthaloyl δ-aminopentanoic acid carboxamides yielded 4aryl-2-piperidone (4-aryl-δ-valerolactam) scaffolds. The required β-CÀ H arylated N-phthaloyl δ-aminopentanoic acid carboxamides were assembled via the Pd(II)-catalyzed, 8aminoquinoline-aided, sp 3 β-CÀ H activation and arylation method. The β-CÀ H arylated N-phthaloyl δ-aminopentanoic acid carboxamides containing both 8-aminoquinoline and Nphthaloyl protecting groups directly underwent the hydrazine-mediated lactamization to afford 4-aryl-2-piperidones. 4-Aryl-2-piperidone scaffolds were then converted into N-functionalized 4-aryl-2-piperidones, 4-arylpiperidines, which are structurally closer to bio-active 4-aryl-2-piperidone and piperidine motifs. A synthetic route for assembling antituberculosis molecule Q203 and its analogues from the corresponding 4-aryl-2-piperidones was also shown.

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“…Alpha, omega-dicarboxylic acids have also been used as precursors or building blocks for the synthesis of interesting bioactive compounds such as inhibitors of CDK4/6-mediated cancer [8], DNA sequence-specific ligands [9], and hydroxyproline analogs showing anti-breast cancer activity [10]. Omega-aminocarboxylic acids including 11-aminoundecanoic acid are useful intermediates for the syntheses of fusidic acid derivatives [11], rolipram-type derivatives [12], and ocotillol-type derivatives [13] with interesting biological activities.…”

Section: Introductionmentioning

confidence: 99%

Bioenzymatic and Chemical Derivatization of Renewable Fatty Acids

Akula

Kwon

2019

Biomolecules

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In addition to our previous efforts toward bioenzymatic and chemical transformations of ricinoleic acid and oleic acid to their corresponding α,ω-dicarboxylic acids via their ester intermediates driven in Escherichia coli cells, several efficient oxidation conditions were investigated and optimized for the conversion of ω-hydroxycarboxylic acids to α,ω-dicarboxylic acids. Pd/C-catalyzed oxidation using NaBH4 in a basic aqueous alcohol and Ni(II) salt-catalyzed oxidation using aqueous sodium hypochlorite were considered to be excellent as a hybrid reaction for three successive chemical reactions (hydrogenation, hydrolysis, and oxidation) and an eco-friendly, cost-effective, and practical approach, respectively. Omega-hydroxycarboxylic acids and ω-aminocarboxylic acid were also easily prepared as useful building blocks for plastics or bioactive compounds from the bioenzymatically driven ester intermediate. The scope of the developed synthetic methods can be utilized for large-scale synthesis and various derivatizations.

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Assembling of medium/long chain-based β-arylated unnatural amino acid derivatives via the Pd(II)-catalyzed sp3 β-C-H arylation and a short route for rolipram-type derivatives

Cited by 17 publications

References 95 publications

A Guide to Directing Group Removal: 8‐Aminoquinoline

A Guide to Directing Group Removal: 8‐Aminoquinoline

Direct Lactamization of β‐Arylated δ‐Aminopentanoic Acid Carboxamides: En Route to 4‐aryl‐2‐Piperidones, Piperidines, Antituberculosis Molecule Q203 (Telacebec) and its Analogues

Bioenzymatic and Chemical Derivatization of Renewable Fatty Acids

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