Photo-oxygenation of Phytol and the Structure Revision of Phytene-1,2-diol from Artemisia annua to Phytene-1-ol-2-Hydroperoxidek

2002 ◽  
Vol 2002 (1) ◽  
pp. 30-33 ◽  
Author(s):  
Ho-Fai Wong ◽  
Geoffrey D. Brown
Keyword(s):  
Double Bond ◽  
Singlet Oxygen ◽  
Natural Product ◽  
Spectral Properties ◽  
Artemisia Annua ◽  
Type Reaction ◽  
Structure Revision

Photo-oxygenation of racemic phytol has yielded two secondary allylic hydroperoxides and an endoperoxide hemi-acetal, which are the expected products from the “ene-type” reaction of singlet oxygen with the tri-substituted double bond in phytol. Spectral properties for one of the diastereoisomers of phytene-1-ol-2-hydroperoxide obtained from synthesis are shown to be identical with those of a natural product previously reported from Artemisia annua, which, it is concluded, was wrongly assigned as phytene-1,2-diol.

Alkyne-Forming Furan Fragmentation: A General Method to Convert Furans into Alkynoic Acids

Synlett ◽  
2019 ◽  
Vol 30 (06) ◽  
pp. 642-646
Author(s):  
Jinghan Gui ◽  
Jiachen Deng
Keyword(s):  
Reaction Mechanism ◽  
Double Bond ◽  
Singlet Oxygen ◽  
Natural Product ◽  
Organic Synthesis ◽  
Bond Cleavage ◽  
Historical Context ◽  
Natural Product Synthesis ◽  
Fragmentation Reaction ◽  
General Method

Furans are readily available and highly reactive heterocycles that serve as versatile four-carbon synthons in organic synthesis. Recently, we discovered that furans, upon oxidation with singlet oxygen, can be transformed into alkynes via dual C–C double-bond cleavage. This Synpacts article presents an overview of the historical context and the development of this furan fragmentation reaction. We also discuss its application in natural product synthesis and a plausible reaction mechanism.1 Introduction2 Background of Alkyne-Forming Furan Fragmentation3 Reaction Development4 Conclusion

scholarly journals Synthesis, Structure Revision, and Absolute Configuration of (+)-Didemniserinolipid B, a Serinol Marine Natural Product from a Tunicate Didemnum sp.

ChemInform ◽  
2003 ◽  
Vol 34 (3) ◽  
Author(s):  
Hiromasa Kiyota ◽  
Darren J. Dixon ◽  
Christine K. Luscombe ◽  
Stephan Hettstedt ◽  
Steven V. Ley
Keyword(s):  
Natural Product ◽  
Absolute Configuration ◽  
Marine Natural Product ◽  
Structure Revision

Short Synthesis of 3-(Hydroxymethyl)xylitol and Structure Revision of the Anti-diabetic Natural Product from Casearia esculenta

2013 ◽  
Vol 15 (21) ◽  
pp. 5610-5612 ◽  
Author(s):  
Ruomeng Wang ◽  
Michael N. Paddon-Row ◽  
Michael S. Sherburn
Keyword(s):  
Natural Product ◽  
Structure Revision ◽  
Short Synthesis

An Example of Ketone Olefination via Praseodymium-Mediated Barbier Reaction in the Presence of Diethyl Phosphite

Synlett ◽  
2019 ◽  
Vol 30 (12) ◽  
pp. 1437-1441
Author(s):  
Xu yan Cao ◽  
Fei Huang ◽  
Songlin Zhang
Keyword(s):  
Double Bond ◽  
Bond Formation ◽  
Point Of View ◽  
Diethyl Phosphite ◽  
Reaction Conditions ◽  
One Pot ◽  
Type Reaction ◽  
Mild Conditions ◽  
Allyl Halides ◽  
Barbier Reaction

The first example of carbon double-bond formation via praseodymium-mediated Barbier type reaction of ketones and allyl halides in the presence of diethyl phosphite is reported. The reaction is highly α-regioselective and conveniently carried out under mild conditions in a one-pot fashion. From a synthetic point of view, a series of conjugated alkenes were obtained in moderate to good yields in this one-pot reaction with practical reaction conditions.

Synthesis, Structure Revision, and Absolute Configuration of (+)-Didemniserinolipid B, a Serinol Marine Natural Product from a TunicateDidemnumsp.

2002 ◽  
Vol 4 (19) ◽  
pp. 3223-3226 ◽  
Author(s):  
Hiromasa Kiyota ◽  
Darren J. Dixon ◽  
Christine K. Luscombe ◽  
Stephan Hettstedt ◽  
Steven V. Ley
Keyword(s):  
Natural Product ◽  
Absolute Configuration ◽  
Marine Natural Product ◽  
Structure Revision

scholarly journals Computed Regioselectivity and Conjectured Biological Activity of Ene Reactions of Singlet Oxygen with the Natural Product Hyperforin

2017 ◽  
Vol 93 (2) ◽  
pp. 626-631 ◽  
Author(s):  
Inna Abramova ◽  
Benjamin Rudshteyn ◽  
Joel F. Liebman ◽  
Alexander Greer
Keyword(s):  
Biological Activity ◽  
Singlet Oxygen ◽  
Natural Product ◽  
Ene Reactions

scholarly journals Synthesis-Guided Structure Revision of the Sarcodonin, Sarcoviolin, and Hydnellin Natural Product Family

2011 ◽  
Vol 76 (4) ◽  
pp. 1013-1030 ◽  
Author(s):  
David W. Lin ◽  
Takeshi Masuda ◽  
Moritz B. Biskup ◽  
Jonathan D. Nelson ◽  
Phil S. Baran
Keyword(s):  
Natural Product ◽  
Product Family ◽  
Structure Revision

Stability of PPV Derivatives: The Effect of Side Group Functionalities

1995 ◽  
Vol 413 ◽  
Author(s):  
B. H. Cumpston ◽  
K. F. Jensen ◽  
F. Klavettert ◽  
E. G. J. Staring ◽  
R. C. J. E. Demand
Keyword(s):  
Double Bond ◽  
Singlet Oxygen ◽  
Degradation Pathway ◽  
Phenylene Vinylene ◽  
Conjugation Length ◽  
Trans Stilbene ◽  
Thin Polymer ◽  
Singlet Oxygen Reaction ◽  
Semi Empirical

ABSTRACTWe have identified excited-state singlet oxygen as a reactive intermediate in the solid state photo-oxidation of two poly(p-phenylene vinylene) (PPV) derivatives, poly(2,5-bis(5,6- cholestanoxy)-1,4-phenylene vinylene) (BCHA-PPV) and poly(2-methoxy,5-(2'-ethyl-hexoxy)- 1,4-phenylene vinylene) (MEH-PPV). Singlet oxygen is photosensitized via energy transfer from the polymer and undergoes 1,2-cycloaddition across the electron-rich vinyl double bond in the backbone of the polymer resulting in the formation of highly oxidized species such as esters. Volatile carbonyl species are also formed, and, consequently, the film thins. This degradation pathway occurs when the polymer film is exposed in air to light having energy above the bandgap of the polymer, from either a low-pressure UV mercury lamp or an Ar+ laser operating at 514 or 457 nm. Interestingly, the singlet oxygen reaction does not take place in model compounds with similar structures such as trans-stilbene. In an effort to understand which properties of the polymer make it susceptible to singlet oxygen attack, we have studied the effect of conjugation length and side groups on the reactivity of thin polymer films. Specifically, the role of electron withdrawing groups, steric protection of the vinyl double bond, and conjugation length effects have been investigated using both FrIR spectroscopy and semi-empirical computational chemistry calculations.

Synthesis, properties and singlet oxygen generation of thiazolidinone double bond linked porphyrin at meso and β-position

RSC Advances ◽  
2016 ◽  
Vol 6 (42) ◽  
pp. 36090-36095 ◽  
Author(s):  
Sohail Ahmad ◽  
Kumar Karitkey Yadav ◽  
Uma Narang ◽  
Soumee Bhattacharya ◽  
Sarangthem Joychandra Singh ◽  
...  
Keyword(s):  
Double Bond ◽  
Singlet Oxygen ◽  
Carbon Disulfide ◽  
Knoevenagel Condensation ◽  
Free Base ◽  
One Pot ◽  
Ethyl Chloroacetate ◽  
Oxygen Generation ◽  
Singlet Oxygen Generation ◽  
Synthesis Properties

Meso and β-substituted free base and zinc metallated thiazolidinone–porphyrin conjugates were synthesized by one pot four component Knoevenagel condensation by utilizing substituted amines, carbon disulfide, ethyl chloroacetate and porphyrin aldehydes.

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