Terpenes and Related Compounds. V

Some studies in the biosynthesis of terpenes and related compounds.

Cyclic terpenes as a class of natural products display a bewildering array of structural types. Well over a hundred different carbon frameworks have been detected so far, many new substances are being currently added to an already impressive list of compounds, and even several representatives of the long-sought group of sesterterpenes have at last made their appearance on the chemical scene14. ...

Coumarins, Xanthones and Related Compounds.

It has long been known that coumarins (α-pyrones) and xanthones (γ-pyrones) together form a large class of naturally occurring compounds exhibiting a wide range of biological activities. However, the interest of the scientific community for these secondary metabolites, as well as for their structural analogues, has never decreased since these “old compounds” are constantly generating promising—...

Pteroylglutamic acid and related compounds.

8ƒ¿-hydroxyflavinmononucleotide and Related Compounds

2•L,3•L,4•L-Triacetyl-FMN has been transformed by selec tive radical bromination into 2•L,3•L,4•L-triacetyl-8ƒ¿-bromo-FMN, and the following hydrolysis of the latter has afforded 8ƒ¿-hydroxy-FMN. The presence of the hydroxy group in the 8ƒ¿ position of 8ƒ¿-hydroxy FMN is confirmed by its acetylation into 2•L,3•L-dracetyl-8ƒ¿-acetoxyribofla vin-4•L,5•L-cyclophosphate. The absorption spectra of t...

III-V Compounds and Alloys: An Update.

The III-V compounds and alloys have been studied for three decades. Until recently, these materials have been commercialized for only a few specialized optoelectronic devices and microwave devices. Advances in thin-film epitaxy techniques, such as liquid phase epitaxy and chemical vapor deposition, are now providing the ability to form good quality lattice-matched heterojunctions with III-V mat...