Pyranone compounds useful to treat retroviral infections

The compound of the formula VI ##STR3## wherein R.sub.2 is a) H.sub.3 C--CH.sub.2 --, or

• b) phenyl-(CH.sub.2).sub.2 --;
• wherein R.sub.3 is the moiety of formula X ##STR4## wherein R.sub.6 is a) H.sub.3 C--(CH.sub.2).sub.2 --, or
• b) phenyl-(CH.sub.2).sub.2 --;
• wherein R.sub.7 is H.sub.3 C--CH.sub.2 --;
• wherein R.sub.9 is --NHSO.sub.2 --het;
• wherein het is 2-pyridinyl substituted at the 5-position by zero (0) or one (1) R.sub.10 ;
• wherein R.sub.10 is
• a) --CN,
• b) --CF.sub.3,
• c) --NH2, or
• d) --CONH.sub.2 ;
• or a pharmaceutically acceptable salt thereof.