Two new diphenyl ethers and a new depside from the lichen Micarea prasina Fr

1984 ◽  
Vol 37 (11) ◽  
pp. 2349 ◽  
Author(s):  
JA Elix ◽  
AJ Jones ◽  
LCBJ Lajide ◽  
PW James
Keyword(s):  
Total Synthesis ◽  
Methyl Esters ◽  
Sodium Hydride ◽  
Hydroxybenzoic Acid ◽  
Type Synthesis ◽  
Enol Ethers ◽  
Diphenyl Ethers ◽  
Key Steps ◽  
Methoxybenzoic Acid

Two new diphenyl ethers, 4-(2-carboxy-3-heptyl-5-methoxyphenoxy)-2-heptyl-6-hydroxybenzoic acid (micareic acid) (13), 4-(2-carboxy-3-heptyl-5-methoxyphenoxy)-2-heptyl-6-hydroxy-3-methoxybenzoic acid (methoxymicareic acid) (27) and a new depside, 4-(2-heptyl-6-hydroxy-4-methoxybenzoyloxy)- 2-heptyl-6-hydroxybenzoic acid (prasinic acid) (34) have been detected in chemical races of the lichen Micarea prasina Fr. and isolated and characterized as the corresponding methyl esters. The structure of the latter compounds has been confirmed by total synthesis. The key steps in the synthesis of the diphenyl ethers (14), (26) involved Ullmann-like condensation between the 3-chloro 2-enone (17) and the phenols (11), (31), and subsequent aromatization of the enol ethers (23) and (32). A biomimetic-type synthesis of methyl micareate (48) has also been achieved by treatment of the depside (33) with sodium hydride in dimethylformamide.

Concise Total Synthesis of Curvulone B

Synlett ◽  
2020 ◽  
Author(s):  
Debendra K. Mohapatra ◽  
Shivalal Banoth ◽  
Utkal Mani Choudhury ◽  
Kanakaraju Marumudi ◽  
Ajit C. Kunwar
Keyword(s):  
Total Synthesis ◽  
Stereoselective Synthesis ◽  
Ring System ◽  
Bond Forming ◽  
Cross Metathesis ◽  
Bond Forming Reactions ◽  
Key Steps

AbstractA concise and convergent stereoselective synthesis of curvulone B is described. The synthesis utilized a tandem isomerization followed by C–O and C–C bond-forming reactions following Mukaiyama-type aldol conditions for the construction of the trans-2,6-disubstituted dihydropyran ring system as the key steps. Other important features of this synthesis are a cross-metathesis, epimerization, and Friedel–Crafts acylation.

First Total Synthesis of a Fluorinated Calystegin

2010 ◽  
Vol 65 (4) ◽  
pp. 445-451 ◽  
Author(s):  
René Csuk ◽  
Erik Prell ◽  
Stefan Reißmann ◽  
Claudia Korb
Keyword(s):  
Total Synthesis ◽  
Ring Opening ◽  
Competitive Inhibitor ◽  
Ring Closure ◽  
Target Compound ◽  
Metathesis Reaction ◽  
Grubbs Catalyst ◽  
Ring Opening Reaction ◽  
Ultrasound Assisted ◽  
Key Steps

A straightforward chiral pool synthesis for the first fluorinated calystegin is described. Key steps of this synthesis include an ultrasound-assisted Zn-mediated tandem ring opening reaction followed by a Grubbs’ catalyst-mediated ring closure metathesis reaction. The target compound is a selective and competitive inhibitor for a β -glycosidase.

scholarly journals Total syntheses of all tri-oxygenated 16-phytoprostane classes via a common precursor constructed by oxidative cyclization and alkyl–alkyl coupling reactions as the key steps

2017 ◽  
Vol 15 (44) ◽  
pp. 9408-9414 ◽  
Author(s):  
Jakub Smrček ◽  
Radek Pohl ◽  
Ullrich Jahn
Keyword(s):  
Total Synthesis ◽  
Oxidative Cyclization ◽  
Coupling Reactions ◽  
Total Syntheses ◽  
Common Precursor ◽  
Key Steps

A parallel total synthesis of 16-F1t-, 16-E1-phytoprostanes and a first synthesis of 16-D1t-phytoprostanes based on a common precursor are described.

scholarly journals First Total Synthesis of Artekeiskeanol A, C and Altissimacoumarin D

SynOpen ◽  
2019 ◽  
Vol 03 (02) ◽  
pp. 49-54 ◽  
Author(s):  
Anil Talakokkula ◽  
Karunakar Baikadi ◽  
A. Narsaiah
Keyword(s):  
Total Synthesis ◽  
Oxidation Reactions ◽  
Total Syntheses ◽  
Riley Oxidation ◽  
Key Steps

The total syntheses of artekeiskeanol A and C, and altissimacoumarin D have been achieved. The syntheses commenced from commercially available starting materials, 2,4-dihydroxybenzaldehyde and geraniol. The key steps involve Wittig and Riley oxidation reactions.

Total syntheses of seminolipid and its analogues by using 2,6-bis(trifluoromethyl)phenylboronic acid as protective reagent

2019 ◽  
Vol 17 (31) ◽  
pp. 7325-7329
Author(s):  
Naoyuki Shimada ◽  
Kenji Fukuhara ◽  
Sari Urata ◽  
Kazuishi Makino
Keyword(s):  
Total Synthesis ◽  
Phenylboronic Acid ◽  
Total Syntheses ◽  
Key Steps

Total synthesis of seminolipid was accomplished via regioselective protection using 2,6-bis(trifluoromethyl)phenylboronic acid followed by regioselective trichloroethyl-protected sulfation as key steps.

scholarly journals The reaction of arylmethyl isocyanides and arylmethylamines with xanthate esters: a facile and unexpected synthesis of carbamothioates

2020 ◽  
Vol 16 ◽  
pp. 159-167
Author(s):  
Narasimhamurthy Rajeev ◽  
Toreshettahally R Swaroop ◽  
Ahmad I Alrawashdeh ◽  
Shofiur Rahman ◽  
Abdullah Alodhayb ◽  
...  
Keyword(s):  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Sodium Hydride ◽  
Unexpected Formation ◽  
Key Steps

An unexpected formation of carbamothioates by a sodium hydride-mediated reaction of arylmethyl isocyanides with xanthate esters in DMF is reported. The products thus obtained were compared with the carbamothioates obtained by the sodium hydride-mediated condensation of the corresponding benzylamines and xanthate esters in DMF. To account for these unexpected reactions, a mechanism is proposed in which the key steps are supported by quantum chemical calculations.

scholarly journals Enantioselective total synthesis of decytospolide A and decytospolide B using an Achmatowicz reaction

2018 ◽  
Vol 16 (33) ◽  
pp. 5979-5986 ◽  
Author(s):  
Arun K. Ghosh ◽  
Hannah M. Simpson ◽  
Anne M. Veitschegger
Keyword(s):  
Total Synthesis ◽  
Transfer Hydrogenation ◽  
Enantioselective Total Synthesis ◽  
Key Steps ◽  
Enantioselective Syntheses

Enantioselective syntheses of decytospolides are described using an Achmatowicz rearrangement, transfer hydrogenation and Friedel–Crafts acylation as the key steps.

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