The disclosure provides compounds having formula (I):

##STR00001##

and the pharmaceutically acceptable salts thereof, wherein R.sub.1, R.sub.2, R.sub.2, and X are as defined as set forth in the specification. Compounds having formula (I) are prodrugs that release glutamine analogs, e.g., 6-diazo-5-oxo-L-norleucine (DON). The disclosure also provides compounds having formula (I) for use in treating cancer.

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.

The present invention provides compounds of Formula (I):

##STR00001##

or a stereoisomer, or a pharmaceutically acceptable salt thereof, wherein all of the variables are as defined herein. These compounds are monoacylglycerol acyltransferase type 2 (MGAT2) inhibitors which may be used as medicaments.

The present invention provides compounds of Formula (I):

##STR00001##

or a stereoisomer, or a pharmaceutically acceptable salt thereof, wherein all of the variables are as defined herein. These compounds are monoacylglycerol acyltransferase type 2 (MGAT2) inhibitors which may be used as medicaments.

Methods of conjugating two molecules are disclosed herein in which a non-polymeric aliphatic dialdehyde or non-polymeric aromatic dialdehyde is reacted with a compound comprising an amine (NH.sub.2) moiety to form a stable product under mild conditions.

Novel compounds of formula (II) are disclosed. Compounds of formula (II) comprise ornithine derivatives or compounds that may metabolize to ornithine. Also disclosed are methods for the treatment of neurodegenerative diseases such as Alzheimer's Disease using compounds of formula (II).

##STR00001##

Novel compounds of formula (II) are disclosed. Compounds of formula (II) comprise ornithine derivatives or compounds that may metabolize to ornithine. Also disclosed are methods for the treatment of neurodegenerative diseases such as Alzheimer's Disease using compounds of formula (II).

##STR00001##

Provided are compositions that include a platelet-activating factor antagonist, pharmaceutical compositions including the platelet-activating factor antagonist, methods of treating a modulating the proliferation of a glioma or a pathological condition resulting from patient having a glioma.

Provided are compositions that include a platelet-activating factor antagonist, pharmaceutical compositions including the platelet-activating factor antagonist, methods of treating a modulating the proliferation of a glioma or a pathological condition resulting from patient having a glioma.