Synthesis of 23-, 25-, 27-, and 29-Membered (Z)-Selective Unsaturated and Saturated Macrocyclic Lactones from 16- and 17-Membered Macrocyclic Lactones and Bromoalcohols by Wittig Reaction, Yamaguchi Macrolactonization, and Photoinduced Decarboxylative Radical Macrolactonization

2019 ◽  
Vol 84 (12) ◽  
pp. 8019-8026 ◽  
Author(s):  
Tomoya Iwasaki ◽  
Yuka Tajimi ◽  
Kenta Kameda ◽  
Callum Kingwell ◽  
William Wcislo ◽  
...  
Keyword(s):  
Wittig Reaction ◽  
Macrocyclic Lactones ◽  
Yamaguchi Macrolactonization

scholarly journals Synthesis of higher sugars as precursors for the synthesis of chiral polyhydroxylated macrocyclic lactones

2000 ◽  
Vol 65 (7) ◽  
pp. 497-505 ◽  
Author(s):  
Momcilo Miljkovic ◽  
Margaret Habash-Marino
Keyword(s):  
Wittig Reaction ◽  
Model Compound ◽  
Carbohydrate Chain ◽  
Macrocyclic Lactones ◽  
General Method

A general method for the synthesis of higher sugars that can be used as precursors for the synthesis of polyhydroxylated macrocyclic lactones (macrolides) was described. The extension of the carbohydrate chain of a hexopyranose was effected at its C(6) hydroxymethyl carbon by coupling of two carbohydrate precursors via Wittig reaction. In this way 6,7-dideoxy-2,3,4,5,8,9,10-hepta-O-methyl-11-O-triphenylmethyl-D-arabino-D-glucoundecanose diethyl dithioacetal (1) was synthesized as a model compound.

Double Ring-Closing Approach for the Synthesis of 2,3,6,7-Substituted Anthracene Derivatives

2020 ◽  
Author(s):  
Birgit Meindl ◽  
Katharina Pfennigbauer ◽  
Berthold Stöger ◽  
Martin Heeney ◽  
Florian Glöcklhofer
Keyword(s):  
Wittig Reaction ◽  
Condensation Reaction ◽  
Synthetic Methods ◽  
Anthracene Derivative ◽  
Double Ring ◽  
Mild Conditions ◽  
Wide Range ◽  
Anthracene Derivatives

Anthracene derivatives have been used for a wide range of applications and many different synthetic methods for their preparation have been developed. However, despite continued synthetic efforts, introducing substituents in some positions has remained difficult. Here we present a method for the synthesis of 2,3,6,7-substituted anthracene derivatives, one of the most challenging anthracene substitution patterns to obtain. The method is exemplified by the preparation of 2,3,6,7-anthracenetetracarbonitrile and employs a newly developed, stable protected 1,2,4,5-benzenetetracarbaldehyde as the precursor. The precursor can be obtained in two scalable synthetic steps from 2,5-dibromoterephthalaldehyde and is converted into the anthracene derivative by a double intermolecular Wittig reaction under very mild conditions followed by a deprotection and intramolecular double ring-closing condensation reaction. Further modification of the precursor is expected to enable the introduction of additional substituents in other positions and may even enable the synthesis of fully substituted anthracene derivatives by the presented approach.<br>

Macrocyclic Lactones for Parasite Control in Equids

2012 ◽  
Vol 13 (6) ◽  
pp. 1070-1077 ◽  
Author(s):  
E. T. Lyons ◽  
S. C. Tolliver
Keyword(s):  
Parasite Control ◽  
Macrocyclic Lactones

Resistance to Macrocyclic Lactones

2012 ◽  
Vol 13 (6) ◽  
pp. 873-887 ◽  
Author(s):  
Adrian J. Wolstenholme ◽  
Ray M. Kaplan
Keyword(s):  
Macrocyclic Lactones

Computational Study on the Kinetics and Mechanisms of Unimolecular Reactions of (Z)-(Z)-N-(λ5-phosphanylidene) Formohydrazonic Formic Anhydride: Intramolecular aza-Wittig Reaction in Competition with Mumm Rearrangement

2020 ◽  
Vol 17 (11) ◽  
pp. 884-889
Author(s):  
Somayeh Mirdoraghi ◽  
Hamed Douroudgari ◽  
Farideh Piri ◽  
Morteza Vahedpour
Keyword(s):  
Rate Constants ◽  
Density Functional ◽  
Wittig Reaction ◽  
Computational Study ◽  
Single Step ◽  
Low Energy ◽  
Coupled Cluster ◽  
Unimolecular Reaction ◽  
Single Step Reaction ◽  
Good Agreement

For (Z)-(Z)-N-(λ5-phosphanylidene) formohydrazonic formic anhydride, Aza-Wittig reaction and Mumm rearrangement are studied using both density functional and coupled cluster theories. For this purpose, two different products starting from one substrate are considered that are competing with each other. The obtained products, P1 and P2, are thermodynamically favorable. The product of the aza-Wittig reaction, P1, is more stable than the product of Mumm rearrangement (P2). For the mentioned products, just one reliable pathway is separately proposed based on unimolecular reaction. Therefore, the rate constants based on RRKM theory in 300-600 K temperature range are calculated. Results show that the P1 generation pathway is a suitable path due to low energy barriers than the path P2. The first path has three steps with three transition states, TS1, TS2, and TS3. The P2 production path is a single-step reaction. In CCSD level, the computed barrier energies are 14.55, 2.196, and 10.67 kcal/mol for Aza-Wittig reaction and 42.41 kcal/mol for Mumm rearrangement in comparison with the corresponding complexes or reactants. For final products, the results of the computational study are in a good agreement with experimental predictions.

scholarly journals Tackling Pristinamycin IIB Problems: Synthetic Studies toward Some Fluorinated Analogs

2020 ◽  
Vol 3 (1) ◽  
pp. 107
Author(s):  
Assia Chebieb ◽  
Chewki Ziani-Cherif
Keyword(s):  
Chemical Structure ◽  
Wittig Reaction ◽  
Antimicrobial Agents ◽  
Synthetic Approach ◽  
Solubility In Water ◽  
Fluorinated Analogs ◽  
Human Therapy ◽  
Primary Structures ◽  
Synthetic Studies

Streptogramins are potent antibiotics against numerous highly resistant pathogens and therefore are used in last-resort human therapy. These antibiotics are formed of both A- and B-group compounds named pristinamycins that differ in their basic primary structures. Although pristinamycin IIB is among the most interesting antibiotics in this family, it presents numerous problems related to its chemical structure, such as instability at most pH levels, weak solubility in water, and resistance by bacteria. As a response to the need for developing new antimicrobial agents, we have designed a new analog of pristinamycin IIB, based most importantly on the introduction of fluorine atoms. We conjectured indeed that the introduced modifications may solve the above-mentioned problems exhibited by pristinamycin IIB. Our multistep synthetic approach relies on few key reactions, namely a Wittig reaction, a Grubbs reaction, and dihydroxy, -difluoro API (Advanced Pharmaceutical Intermediate) synthesis

scholarly journals Stereoselective Synthesis of Tetraalkyl Cyclobutene-1,2,3,4-tetracarboxylates. Synthesis of Tetraalkyl (Z,Z)-Buta-1,3-diene-1,2,3,4-tetracarboxylates

1999 ◽  
Vol 23 (8) ◽  
pp. 512-513
Author(s):  
Issa Yavari ◽  
Farahnaz Nourmohammadian
Keyword(s):  
Ring Opening ◽  
Wittig Reaction ◽  
Stereoselective Synthesis ◽  
Intramolecular Wittig Reaction ◽  
Ring Opening Reactions ◽  
Boiling Toluene

Tetraalkyl cyclobutene-1,2,3,4-tetracarboxylates, prepared by intramolecular Wittig reaction between a vinylphosphonium salt and diethyl 2-oxobutanedioate, undergo electrocyclic ring-opening reactions, in boiling toluene, to produce highly electron-deficient 1,3-dienes.

Theoretical Calculations on the Wittig Reaction Revisited

1998 ◽  
Vol 120 (30) ◽  
pp. 7530-7536 ◽  
Author(s):  
Hiroshi Yamataka ◽  
Shigeru Nagase
Keyword(s):  
Wittig Reaction ◽  
Theoretical Calculations
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