Investigations into the bioorganic chemistry of sterol synthesis have led to various advances
in both the organic and biological provinces. Along organic lines, there have been …

After a quiet period of over two decades in the study of the mechanistic details of the
cyclization step in sterol biosynthesis, there has recently been a renaissance in this field due …

In attempts to simulate the obligatory end double bond oxidation triggering the over-all
biological conversion of squalene to sterols, van Tamelen and Curphey (1) observed …

Past studies have revealed that inthe nonenzymic generation of the AB2 and ABC3 ring
systems of polycyclicterpenoids (including the lanosterol type) from polyene terminal …

Figure 1. X-Ray structure of (p-bromophenyl) urethane 5. Hydrogen atoms have been
included at C (5), C (8), C (9), C (13), and C (14) in order to indicate the stereochemistry at …

The enzymatic cyclizations of squalene (1) and oxidosqualene (2)(Chart I) are the most
remarkable steps in the biosynthesis of steroids and triterpenoids. Woodward and Bloch first …

This article reviews the design and study, in our own laboratory and others, of new steroidal
triterpenes with a modified lanosterol or cycloartenol frame. These compounds, along with a …

Cell-free systems from the protozoon Tetrahymena pyriformis and the bacterium
Alicyclobacillus acidocaldarius normally convert squalene into pentacyclic triterpenes of the …

Abstract The 2, 3-oxido squalene (SO) cyclases represent a group of enzymes which convert
SO into polycyclic triterpenoids such as lanosterol, cycloartenol, cucurbitadienol and β …

The question is rarely asked, why is it that only certain chemical structures and not others
are present in living systems? Or, put differently, can we rationalize the detailed design and …