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4 article(s) from Sharma, Amit Raj

Tenacibactins K–M, cytotoxic siderophores from a coral-associated gliding bacterium of the genus Tenacibaculum

Yasuhiro Igarashi,
Yiwei Ge,
Tao Zhou,
Amit Raj Sharma,
Enjuro Harunari,
Naoya Oku and
Agus Trianto

Full Research Paper
Published 13 Jan 2022

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1. Graphical Abstract
2. Figure 1: Structures of tenacibactins K–M (1–3).
  
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3. Figure 2: Key 2D-NMR correlations for 1–3.
  
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4. Figure 3: (a) Partial ¹H NMR spectra of 1 at 25 and 50 °C in DMSO-d₆; (b) magnified HMBC spectrum of 1 at 25 ...
  
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5. Figure 4: MS/MS spectrum of 1 acquired on a quadrupole time-of-flight mass spectrometer in the negative ion m...
  
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6. Scheme 1: MS/MS fragmentation pathway for compound 1.
  
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Graphical Abstract

Beilstein J. Org. Chem. 2022, 18, 110–119, doi:10.3762/bjoc.18.12

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Nocarimidazoles C and D, antimicrobial alkanoylimidazoles from a coral-derived actinomycete Kocuria sp.: application of ¹J_C,H coupling constants for the unequivocal determination of substituted imidazoles and stereochemical diversity of anteisoalkyl chains in microbial metabolites

Md. Rokon Ul Karim,
Enjuro Harunari,
Amit Raj Sharma,
Naoya Oku,
Kazuaki Akasaka,
Daisuke Urabe,
Mada Triandala Sibero and
Yasuhiro Igarashi

Full Research Paper
Published 05 Nov 2020

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1. Graphical Abstract
2. Figure 1: Structure of the nocarimidazoles 1–4 and the bulbimidazoles 5–7.
  
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3. Figure 2: COSY and key HMBC correlations for 1 and 2.
  
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4. Scheme 1: Synthesis of the model compounds 8 and 9.
  
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5. Figure 3: ¹J_C,H coupling constant for the imidazole ring of the natural products 1 and 5 and the model compou...
  
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6. Figure 4: Determination of the absolute configuration of 1 (a), 4 (b), and 5 (c) by the Ohrui–Akasaka method.
  
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7. Figure 5: Stereochemical diversity of the anteiso-chain chirality in microbial metabolites.
  
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Graphical Abstract

Beilstein J. Org. Chem. 2020, 16, 2719–2727, doi:10.3762/bjoc.16.222

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Two antibacterial and PPARα/γ-agonistic unsaturated keto fatty acids from a coral-associated actinomycete of the genus Micrococcus

Amit Raj Sharma,
Enjuro Harunari,
Naoya Oku,
Nobuyasu Matsuura,
Agus Trianto and
Yasuhiro Igarashi

Full Research Paper
Published 02 Mar 2020

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1. Graphical Abstract
2. Figure 1: Structures of (6E,8Z)- and (6E,8E)-5-oxo-6,8-tetradecadienoic acids (1 and 2).
  
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3. Figure 2: COSY and key HMBC correlations for 1 and 2.
  
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4. Figure 3: Spin system simulation for the C8–C9 double bond of 2.
  
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5. Figure 4: Natural keto fatty acids of various origins.
  
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6. Figure 5: PPAR activation by 1 and 2.
  
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Graphical Abstract

Beilstein J. Org. Chem. 2020, 16, 297–304, doi:10.3762/bjoc.16.29

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Isolation and biosynthesis of an unsaturated fatty acid with unusual methylation pattern from a coral-associated bacterium Microbulbifer sp.

Amit Raj Sharma,
Enjuro Harunari,
Tao Zhou,
Agus Trianto and
Yasuhiro Igarashi

Full Research Paper
Published 30 Sep 2019

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1. Graphical Abstract
2. Figure 1: Structure of (2Z,4E)-3-methyl-2,4-decadienoic acid (1).
  
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3. Figure 2: COSY and key HMBC correlations for 1.
  
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4. Figure 3: Methylation pattern that can occur in fatty acids and polyketides.
  
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5. Scheme 1: C-Methylation of alkenyl carbon in sphingolipid biosynthesis.
  
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6. Figure 4: Incorporation of ¹³C-labeled precursors into 1.
  
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7. Scheme 2: Biosynthesis of tuberculostearic acid in Mycobacterium.
  
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8. Scheme 3: Possible methylation mechanism for compound 1.
  
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Graphical Abstract

Beilstein J. Org. Chem. 2019, 15, 2327–2332, doi:10.3762/bjoc.15.225

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