or r 3 can be taken together with r 4 to form cyclopropyl or cyclobutyl r 4 is selected from h and c 1 c 4 alkyl said alkyl is optionally substituted with one or more substituents selected from r u2032 r 5 is selected from h and c 1 c 4 alkyl or r 5 can be taken together with r 1 to form a monocyclic heterocycle which is optionally substituted with one or more substituents selected from r u2032 r u2033 is selected from h and c 1 c 4 alkyl wherein said alkyl is optionally substituted with one or more substituents selected from halogen and oh l 1 is a c 4 c 22 alkyl or a c 4 c 22 alkenyl and in another embodiment of this invention the cationic lipids are illustrated by the formula a r 1 and r 2 are independently selected from h methyl and ethyl wherein said methyl and ethyl are optionally substituted with one or more substituents selected from r u2032 or r 1 and r 2 can be taken together with the nitrogen to which they are attached to form a monocyclic heterocycle which is optionally substituted with one or more substituents selected from r u2032.