Methods for preparing isotopically modified 1,4-diene systems from non-isotopically modified 1,4-dienes involve selective oxidation of one or more bis-allylic position(s), or the preparation of isotopically modified 1,4-diene systems via trapping pi-allylic complexes with a source of deuterium or tritium. Such methods are useful for preparing isotopically modified polyunsaturated lipid including polyunsaturated fatty acids and polyunsaturated fatty acid derivatives.

In one aspect, the invention provides a method for synthesizing a fatty olefin derivative. The method includes: a) contacting an olefin according to Formula I ##STR00001##
with a metathesis reaction partner according to Formula IIb ##STR00002##
in the presence of a metathesis catalyst under conditions sufficient to form a metathesis product according to Formula IIIb: ##STR00003##
and b) converting the metathesis product to the fatty olefin derivative. Each R.sup.1 is independently selected from H, C.sub.1-18 alkyl, and C.sub.2-18 alkenyl; R.sup.2b is C.sub.1-8 alkyl; subscript y is an integer ranging from 0 to 17; and subscript z is an integer ranging from 0 to 17. In certain embodiments, the metathesis catalyst is a tungsten catalyst or a molybdenum catalyst. In various embodiments, the fatty olefin derivative is a pheromone. Pheromone compositions and methods of using them are also described.

In one aspect, the invention provides a method for synthesizing a fatty olefin derivative. The method includes: a) contacting an olefin according to Formula I ##STR00001##
with a metathesis reaction partner according to Formula IIb ##STR00002##
in the presence of a metathesis catalyst under conditions sufficient to form a metathesis product according to Formula IIIb: ##STR00003##
and b) converting the metathesis product to the fatty olefin derivative. Each R.sup.1 is independently selected from H, C.sub.1-18 alkyl, and C.sub.2-18 alkenyl; R.sup.2b is C.sub.1-8 alkyl; subscript y is an integer ranging from 0 to 17; and subscript z is an integer ranging from 0 to 17. In certain embodiments, the metathesis catalyst is a tungsten catalyst or a molybdenum catalyst. In various embodiments, the fatty olefin derivative is a pheromone. Pheromone compositions and methods of using them are also described.

Methods for preparing isotopically modified 1,4-diene systems from non-isotopically modified 1,4-dienes involve selective oxidation of one or more bis-allylic position(s), or the preparation of isotopically modified 1,4-diene systems via trapping pi-allylic complexes with a source of deuterium or tritium. Such methods are useful for preparing isotopically modified polyunsaturated lipid including polyunsaturated fatty acids and polyunsaturated fatty acid derivatives.

Methods for preparing isotopically modified 1,4-diene systems from non-isotopically modified 1,4-dienes involve selective oxidation of one or more bis-allylic position(s), or the preparation of isotopically modified 1,4-diene systems via trapping pi-allylic complexes with a source of deuterium or tritium. Such methods are useful for preparing isotopically modified polyunsaturated lipid including polyunsaturated fatty acids and polyunsaturated fatty acid derivatives.

An improved method for preparing squalene from a squalene-containing composition, said method comprising the steps of (a) a purification distillation carried out at a temperature T.sub.1 (b) a denaturing distillation carried out at a temperature T.sub.2; wherein steps (a) and (b) may be performed in either order; T.sub.1 and T.sub.2 are sufficient to cause squalene to boil; T.sub.2>T.sub.1; and T.sub.2>200 C.

An improved method for preparing squalene from a squalene-containing composition, said method comprising the steps of (a) a purification distillation carried out at a temperature T.sub.1 (b) a denaturing distillation carried out at a temperature T.sub.2; wherein steps (a) and (b) may be performed in either order; T.sub.1 and T.sub.2 are sufficient to cause squalene to boil; T.sub.2>T.sub.1; and T.sub.2>200 C.

An improved method for preparing squalene from a squalene-containing composition, said method comprising the steps of (a) a purification distillation carried out at a temperature T.sub.1 (b) a denaturing distillation carried out at a temperature T.sub.2; wherein steps (a) and (b) may be performed in either order; T.sub.1 and T.sub.2 are sufficient to cause squalene to boil; T.sub.2>T.sub.1; and T.sub.2>200 C.

An improved method for preparing squalene from a squalene-containing composition, said method comprising the steps of (a) a purification distillation carried out at a temperature T.sub.1 (b) a denaturing distillation carried out at a temperature T.sub.2; wherein steps (a) and (b) may be performed in either order; T.sub.1 and T.sub.2 are sufficient to cause squalene to boil; T.sub.2>T.sub.1; and T.sub.2>200 C.

The present disclosure provides novel polypeptides with 3-buten-2-ol dehydratase activity, polypeptides with catalytic activity in the conversion of 3-methyl-3-buten-2-ol to isoprene, and crystal structure data for one of such polypeptides. Methods of making and using the polypeptides and their related crystal structure data are also provided.