The Adolph Coors Co. has ruled out building a brewery in North Carolina and now says a southern Virginia site is its "primary interest" for an East Coast plant.

The Colorado brewer disclosed yesterday it has dropped its options on land in Anson County, N.C., but is extending its rights to buy a brewery site in Rockingham County, Virginia.

Coors' officials said the company has negotiated six-month extensions on options to buy about 2,300 acres of land along the Shenandoah River near Elkton. The options were to have expired this month.

The Rockingham County Board of Supervisors has already agreed to rezone the property to permit construction of the brewery. Opponents have appealed the ruling to the Virginia Supreme Court, claiming the supervisors illegally held secret meetings to discuss the controversial issue.

While saying the Virginia site is at the top of their list, Coors officials continued to insist they are only looking for "a potential site for a second brewery" and have made no decision to expand into the East.

Coors now makes all its beer at a Golden, Colo., plant that is the largest brewery in the world. But its output is not enough to supply the whole country, so Coors now restricts its official distribution network to the western states. The beer is sold by some Washington area liquor stores who buy supplies outside the company's regular dealer network.

Coors executives have hinted that the East Coast plant might brew a "superpremium" beer under a different name, to distinguish it from the Colorado-brewed brand.

Advertising Age reported this week that the company is considering calling the new brand "Herman Joseph's" beer, after Coors' founder, Adolph Herman Joseph Coors.

Coors' spokesman said yesterday the brewery has set no timetable for making a decision on its East Coast expansion, but the six-month extension on the Rockingham County option seemed to set a July 1 deadline.

A site near Vonore, Tenn., is also being studied by Coors, but only as a back-up in case problems develop in Virginia, he said. Coors decided against the North Carolina site because of water supply problems and failure to reach agreements with two large land owners.