Two Natural Acetylenic Aromatic Carotenoids

Synthesis of High Carbon Materials from Acetylenic Precursors. Preparation of Aromatic Monomers Bearing Multiple Ethynyl Groups1

The synthesis of polyethynyl aromatics as starting materials for the preparation of highly cross-linked organic solids containing high atom fractions of carbon is described. Treatment of bromoand iodoaromatic compounds with (trimethylsily1)acetylene (TMSA) in the presence of palladium(0) and copper(1) in amine solvents yields (trimethylsily1)ethynyl-substituted aromatics. The TMS protecting gro...

Molecular folding of C60 acetylenic cyclophanes: pi-stacking of superimposed aromatic rings.

[structure: see text] The syntheses of two distinct families of phenylyne helical cyclophanes with potential for organic materials are described. The meta-bonded atropisomers afford interesting bowtie-like and butterfly-like conformers from a palladium(0), copper-mediated coupling sequence. Molecular modeling revealed the contrasting stereochemistry in these systems from differential molecular ...

Two-photon absorption spectra of carotenoids compounds

Use of natural carotenoids for pigmentation in fishes

Pigmentation is one of the important quality attributes of the fish for consumer acceptability. Carotenoids are responsible for pigmentation of muscle in food fish and skin colour in ornamental fish. As fish is not capable of synthesizing carotenoids de novo there is a need to incorporate carotenoids in the diet of cultured species. Since synthetic carotenoids are known to have deteriorating ef...

Recent advances in the chemistry of natural carotenoids.

INTRODUCTION One may regard the first epoch in the structural studies of naturally occurring carotenoids as terminated with the authoritative monograph by Karrer and Jucker1 in 1948. In the classical period structural determinations of carotenoids, derived mainly from plant sources, were carried out by semi-micro methods by means of chemical degradation. Useful methods such as various types of ...