Claims
- 1. A compound represented by the structural formula ##STR13## wherein R.sub.1 is selected from straight chain alkyl groups and aryl groups having up to about 8 carbon atoms,
- R.sub.2 is an alkyl or aryl group having up to about 8 carbon atoms, and
- R.sub.3 and R.sub.4 are independently selected from alkyl groups having up to about 4 carbon atoms.
- 2. The compound of claim 1 wherein both R.sub.3 and R.sub.4 are methyl.
- 3. The compound of claim 1 wherein R.sub.1 and R.sub.2 each are a straight chain alkyl group of up to about 8 carbon atoms.
- 4. The compound of claim 1 wherein R.sub.1 and R.sub.2 are methyl and R.sub.3 and R.sub.4 are methyl.
CROSS REFERENCE APPLICATION
This application is a division of application Ser. No. 542,621, filed June 25, 1990, now U.S. Pat. No. 5,061,799.
US Referenced Citations (6)
Divisions (1)
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Number |
Date |
Country |
Parent |
542621 |
Jun 1990 |
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