Processes for preparing 5,5-dimethyl-3-methylenepyrrolidin-2-one, (S)-3,5,5-trimethylpyrrolidine-2-one, (R)-3,5,5-trimethylpyrrolidine-2-one, (S)-2,4,4-trimethylpyrrolidine, and (R)-2,4,4-trimethylpyrrolidine, and their salt forms are disclosed.

##STR00001##

The invention provides heterocyclic compounds with quaternary centers and methods of preparing compounds. Methods include the method for the preparation of a compound of Formula (II):

##STR00001##

comprising treating a compound of Formula (I):

##STR00002##

with a transition metal catalyst and under alkylation conditions as valence and stability permit.

The invention provides heterocyclic compounds with quaternary centers and methods of preparing compounds. Methods include the method for the preparation of a compound of Formula (II):

##STR00001##

comprising treating a compound of Formula (I):

##STR00002##

with a transition metal catalyst and under alkylation conditions as valence and stability permit.

Compounds and methods of modulating 15-PGDH activity, modulating tissue prostaglandin levels, treating disease, diseases disorders, or conditions in which it is desired to modulate 15-PGDH activity and/or prostaglandin levels include 15-PGDH inhibitors and 15-PGDH activators described herein.

Compounds and methods of modulating 15-PGDH activity, modulating tissue prostaglandin levels, treating disease, diseases disorders, or conditions in which it is desired to modulate 15-PGDH activity and/or prostaglandin levels include 15-PGDH inhibitors and 15-PGDH activators described herein.

The invention relates to a process for the production of amide bonds, in particular peptide bonds, with the aid of novel amide linking reagents containing an anion of the formula (I), to the novel reagents, and to the preparation thereof.

Compounds and methods of modulating 15-PGDH activity, modulating tissue prostaglandin levels, treating disease, diseases disorders, or conditions in which it is desired to modulate 15-PGDH activity and/or prostaglandin levels include 15-PGDH inhibitors and 15-PGDH activators described herein.

Compounds and methods of modulating 15-PGDH activity, modulating tissue prostaglandin levels, treating disease, diseases disorders, or conditions in which it is desired to modulate 15-PGDH activity and/or prostaglandin levels include 15-PGDH inhibitors and 15-PGDH activators described herein.

The invention relates to a process for the production of amide bonds, in particular peptide bonds, with the aid of novel amide linking reagents containing an anion of the formula (I), to the novel reagents, and to the preparation thereof.

In one aspect, the invention relates to compounds having the formula:

##STR00001##

where R.sup.1-R.sup.6, a, b, and Z are as defined in the specification, or a pharmaceutically acceptable salt thereof. These compounds have neprilysin inhibition activity. In another aspect, the invention relates to pharmaceutical compositions comprising such compounds; methods of using such compounds; and processes and intermediates for preparing such compounds.