Synthesis of the Demospongic Compounds, (6Z, 11Z)-Octadecadienoic Acid and (6Z, 11Z)-Eicosadienoic Acid

Kulkarni, B. A.; Chattopadhyay, Sharmila; Chattopadhyay, Angshuman; Mamdapur, V. R.

doi:10.3390/jan97p2

Cited by 16 publications

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

Wittig Reaction

2010

Comprehensive Organic Name Reactions and Reagents

View full text Add to dashboard Cite

The synthesis of an olefin from the reaction between a carbonyl compound (aldehyde or ketone) and a phosphonium ylide, via either a betaine and/or oxaphosphetane intermediate is generally known as the Wittig reaction. Occasionally, it is also referred to as the Wittig alkenylation or Wittig process. The extension of this reaction by the application of a phosphine oxide carbanion, instead of a phosphonium ylide is known as the Horner reaction or Wittig Horner reaction, while the preparation of olefin from a phosphonate carbanion is commonly referred to as the Horner–Wadsworth–Emmons olefination. Several other extensions of this reaction have been addressed. All the reaction steps of the Wittig reaction have been discussed. The reversible process to give the carbonyl compound and phosphorane is also possible, and such reversible reaction is known as the retro ‐Wittig reaction. The most important feature of the Wittig reaction is probably the easy control of stereochemistry of olefins (i.e., either Z ‐ or E ‐configuration). It has been observed that ultimate configuration of olefins depends on many factors, such as the structure of phosphoranes, the base and the solvent used, the concentration of ylide, and the reaction temperature. In particular, the Z ‐selectivity from nonstabilized ylides can be further enhanced by replacement of the phenyl group in triphenylphosphane moiety with either a 2‐pyridyl or 2‐furyl group. It has been reported that even the replacement of one phenyl ring by a pyridyl group can apparently increase the Z ‐selectivity without affecting the yields of olefins. It has been reported that E ‐olefin is the major product in the protic solvent, whereas Z ‐olefin predominates in the Wittig reactions when carried out in aprotic media. Other facets of the Wittig reaction have also been discussed, which include, application of the catalysts and the enhancement of reactivity in organic solvent by the application of a phase‐transfer catalyst or promotion of the reaction by photochemical or microwave irradiation. This reaction has very wide applications in organic synthesis, such as transformation of unprotected carbohydrates and preparation of artificial carbon‐linked (1,6)‐oligosaccharides.

show abstract

Wittig Reaction

2010

Comprehensive Organic Name Reactions and Reagents

View full text Add to dashboard Cite

show abstract

Porifera (Sponges)–5

Kornprobst

2014

Encyclopedia of Marine Natural Products

View full text Add to dashboard Cite

A reanalysis of phospholipid fatty acids as ecological biomarkers for methanotrophic bacteria

et al. 2009

View full text Add to dashboard Cite

Aerobic methane-oxidizing bacteria (MB) are the primary terrestrial sinks for the greenhouse gas methane. A distinct characteristic of MB is the presence of specific phospholipid ester-linked fatty acids (PLFA) in their membranes that differentiate them from each other and also from all other organisms. These distinct PLFA patterns facilitate microbial ecology studies. For example, the assimilation of C from methane into PLFA can be traced in environmental samples using stable isotope ( 13 C) probing (SIP), which links the activity of MB to their community composition in situ. However, the phylogenetic resolution of this method is low because of a lack of PLFA profiles from cultured MB species. In this study, PLFA profiles of 22 alphaproteobacterial (type II) MB were analysed after growth on methane, methanol or both substrates together. Growth on different substrates did not affect the PLFA profiles of the investigated strains. A number of Methylocystis strains contained novel C18:2 fatty acids (x7c,12c and x6c,12c) that can be used as diagnostic biomarkers. The detection of these novel PLFA, combined with the analyses of multiple type II strains, increased the phylogenetic resolution of PLFA analysis substantially. Multivariate analysis of the expanded MB PLFA database identified species groups that closely reflected phylogenies based on 16S rRNA and pmoA gene sequences. The PLFA database therefore provides a robust framework for linking identity to activity in MB communities with a higher resolution than was previously possible.

show abstract

Synthesis of the Demospongic Compounds, (6Z, 11Z)-Octadecadienoic Acid and (6Z, 11Z)-Eicosadienoic Acid

Cited by 16 publications

References 14 publications

Wittig Reaction

Wittig Reaction

Porifera (Sponges)–5

A reanalysis of phospholipid fatty acids as ecological biomarkers for methanotrophic bacteria

Contact Info

Product

Resources

About