scholarly journals A synthetic approach to resistomycin

1977 ◽  
Vol 55 (5) ◽  
pp. 785-791 ◽  
Author(s):  
John F. Kingston ◽  
Larry Weiler
Keyword(s):  
Synthetic Approach ◽  
Synthetic Route ◽  
Acid Catalyzed ◽  
Key Steps

An outline of a synthetic route to the antibiotic resistomycin is presented. We report the successful construction of an intermediate containing all of the carbon atoms in resistomycin with requisite functionalities. The key steps involved an aldol type condensation of the dianion from 2,4,6-trimethoxybenzoylacetone and a suitable acetophenone. This was followed by a novel acid-catalyzed cyclization–condensation to form the naphthalene intermediate required in our scheme.

Synthetic studies towards bruceantin. Part 2. The synthesis of a pentacyclic intermediate

1991 ◽  
Vol 69 (4) ◽  
pp. 723-731 ◽  
Author(s):  
Sultan Darvesh ◽  
Andrew S. Grant ◽  
David I. MaGee ◽  
Zdenek Valenta
Keyword(s):  
Key Words ◽  
Michael Reaction ◽  
Sigmatropic Rearrangement ◽  
Synthetic Approach ◽  
Forming Strategy ◽  
Acid Catalyzed ◽  
Synthetic Studies ◽  
Key Steps

In a synthetic approach to the quassinoid bruceantin (2), the key intermediate 8 obtained via alkylation of a dianion has been transformed into the pentacyclic intermediate 33 via an ABDC ring forming strategy. The key steps involved in this route are as follows: a unique acid catalyzed cyclization, 19 → 20; an intramolecular Michael reaction, 24 → 28; and an allyl sulfoxide [2,3]-sigmatropic rearrangement to introduce the axial C12 alcohol, 31 → 33. Key words: bruceantin, quassinoids, cyclization, sulfoxides, sigmatropic rearrangement.

scholarly journals Studies on the Enantioselective Synthesis of E-Ethylidene-bearing Spiro[indolizidine-1,3′-oxindole] Alkaloids

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 428
Author(s):  
Nihan Yayik ◽  
Maria Pérez ◽  
Elies Molins ◽  
Joan Bosch ◽  
Mercedes Amat
Keyword(s):  
Ring System ◽  
Enantioselective Synthesis ◽  
Synthetic Route ◽  
Hydroxymethyl Group ◽  
Hydride Reduction ◽  
Lactam Carbonyl ◽  
Key Steps ◽  
Oxindole Alkaloids

A synthetic route for the enantioselective construction of the tetracyclic spiro[indolizidine-1,3′-oxindole] framework present in a large number of oxindole alkaloids, with a cis H-3/H-15 stereochemistry, a functionalized two-carbon substituent at C-15, and an E-ethylidene substituent at C-20, is reported. The key steps of the synthesis are the generation of the tetracyclic spirooxindole ring system by stereoselective spirocyclization from a tryptophanol-derived oxazolopiperidone lactam, the removal of the hydroxymethyl group, and the stereoselective introduction of the E-ethylidene substituent by acetylation at the α-position of the lactam carbonyl, followed by hydride reduction and elimination. Following this route, the 21-oxo derivative of the enantiomer of the alkaloid 7(S)-geissoschizol oxindole has been prepared.

Enantioselective Synthesis of the Sex Pheromone of Lichen Moth, Miltochrista calamine, and Its Diastereomer

Synlett ◽  
2021 ◽  
Author(s):  
Jiangchun Zhong ◽  
Gucheng Yuan ◽  
Jiawei Liu ◽  
Shihang Yu ◽  
Xueyang Wang ◽  
...  
Keyword(s):  
Sex Pheromone ◽  
Enantioselective Synthesis ◽  
Synthetic Approach ◽  
Chiral Auxiliaries ◽  
Synthetic Sex Pheromone ◽  
Key Steps

AbstractThe synthesis of a Miltochrista calamine sex pheromone and its diastereomer has been developed. The key steps of the synthetic approach involved Evans’ chiral auxiliaries and the addition of alkyne to aldehyde, which were firstly applied to prepare this sex pheromone and its diastereomer. The synthetic sex pheromone could be used to trap insects and study physiological and ecological questions of the lichen moth.

Post-synthetic methods for functionalization of imidazole-fused porphyrins

2018 ◽  
Vol 22 (08) ◽  
pp. 619-631 ◽  
Author(s):  
Inna A. Abdulaeva ◽  
Kirill P. Birin ◽  
Yulia G. Gorbunova ◽  
Aslan Yu. Tsivadze ◽  
Alla Bessmertnykh-Lemeune
Keyword(s):  
Aromatic Aldehyde ◽  
Synthetic Methods ◽  
Synthetic Approach ◽  
Synthetic Route ◽  
Bond Forming ◽  
The Core ◽  
Material Chemistry ◽  
Bond Forming Reactions ◽  
Palladium Catalyzed

Several methods for the post-synthetic modification of imidazo[4,5-[Formula: see text]]porphyrins are reported. First, a synthetic approach to the isomeric difunctionalized porphyrins, containing two [Formula: see text]-fused 2-aryl-1[Formula: see text]-imidazole cycles at adjacent or opposite pyrrole rings of the macrocycle is developed. The core chemistry of this synthetic route is the transformation of 2-aryl-1[Formula: see text]-imidazo[4,5-[Formula: see text]]porphyrins into corresponding imidazodioxochlorins followed by Debus–Radziszewski condensation with aromatic aldehyde. Next, 2-(4-bromophenyl)-1[Formula: see text]-imidazo[4,5-[Formula: see text]]-5,10,15,20-tetramesitylporphyrin was transformed into useful carboxy- and phosphonato-substituted precursors for material chemistry according to palladium-catalyzed C–C and C–P bond forming reactions.

A Concise Enantioselective Synthesis of (S)-Preclamol via Asymmetric Catalytic Negishi Cross-Coupling Reaction

Synlett ◽  
2019 ◽  
Vol 30 (07) ◽  
pp. 860-862 ◽  
Author(s):  
Yun Zhou ◽  
Chunxiao Liu ◽  
Lifeng Wang ◽  
Leng Han ◽  
Shicong Hou ◽  
...  
Keyword(s):  
Total Yield ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Enantioselective Synthesis ◽  
Synthetic Approach ◽  
Chiral Drugs ◽  
Asymmetric Catalytic ◽  
Cross Coupling Reaction ◽  
Tertiary Carbon ◽  
Key Steps

A novel, concise, and efficient enantioselective synthesis of (S)-preclamol (87% ee, 51% total yield) has been developed. The key steps of this synthetic approach included cobalt-catalyzed asymmetric catalytic cross-coupling of α-bromo ester with arylzinc and the reduction of chiral ester to diol with a tertiary carbon atom. Moreover, it was demonstrated that our enantioselective Negishi cross-coupling was a powerful tool to construct stereogenic benzylmethyl center in chiral drugs on a gram scale.

scholarly journals Synthesis of the Trans-Syn-Trans Perhydrobenzo[f]chromene Ring System

2021 ◽  
Author(s):  
Amjad Ayad Qatran AlKhdhairawi ◽  
Syahrul Imran ◽  
Nurhuda Manshoor ◽  
Geoffrey A. Cordell ◽  
Narendra Babu Shivanagere Nagojappa ◽  
...  
Keyword(s):  
Stereoselective Synthesis ◽  
Ring System ◽  
Unsaturated Ketone ◽  
Target Compound ◽  
Reductive Alkylation ◽  
Acid Catalyzed ◽  
Key Steps ◽  
Chromene Ring

<p>A stereoselective synthesis of the <i>trans</i>-<i>syn</i>-<i>trans </i>perhydrobenzo[<i>f</i>]chromene skeleton is presented. The target compound <b>3 </b>was achieved in six steps starting from the (<i>S</i>)-(+)-Wieland-Miescher ketone. Key steps include the sp<sup>2</sup> alkylation at the a-carbon of an unsaturated ketone, Birch-type reductive alkylation, and an acid-catalyzed cyclization. </p>

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