A D.C. Superior Court judge yesterday rejected pleas for leniency and sentenced two Northwest Washington teen-agers to a minimum of 16 years in prison for the May 28 murder of the owner of a popular Capitol Hill delicatessen.

Judge Robert M. Scott sentenced William A. Jackson, 18, of 1151 New Jersey Ave. NW, and Spencer A. Wade, 19, of 2911 13th St. NW, to serve from 16 to 48 years for the beating death of 64-year-old Charles Solomon as well as for attempted robbery of the restaurant and an unrelated burglary two weeks before the murder.

Solomon, who usually closed the restaurant at 4 p.m., returned there by chance several hours later on an errand, surprising Jackson, who worked there as a busboy, and Wade in the middle of a burglary, testimony showed. Both teen-agers originally gave police conflicting statements of the incident, each depicting the other as more involved in actually striking Solomon.

During the emotional 40-minute hearing yesterday, defense attorneys Sarah Brown and Timothy Junkin engaged in a polite but sharp dispute with Scott over what type of sentence should be imposed and whether the youths were capable of rehabilitating themselves.

The lawyers asked that the youths be sentenced under a law which would give corrections officials discretion on when to release them and that Scott sentence them to a federal institution where they might receive substantial vocational training.

The lawyers argued that the two youths, both of whom had spent most of their lives shuttling from one foster home or youth institution to another, had no intention of meeting Solomon in the restaurant. "Mr. Solomon was a wonderful man," Brown quoted Jackson as telling her.

"I am asking you to sentence him Wade as a criminal, not a murderer," Junkin pleaded. "Don't lock him up and throw away the key . . . he's only 19."

Jackson and Wade each expressed remorse for the incident. "I never intended to hurt him," Jackson said. "I'm deeply sorry for what I've done." Wade also said he was sorry for the crime and requested that Scott send him to an institution where he could get vocational training.

Scott interrupted the youths and their lawyers several times to cite portions of their original statements to police which indicated that Solomon had been beaten severely with a crowbar. " 'Jackson said he had to kill him,' " Scott said, quoting Wade's statement.

Both youths, he said, had long criminal records as juveniles. Scott said he agreed with the prosecutor, Assistant U.S. Attorney Alan Strasser, that neither youth would benefit from shorter sentences at a federal institution.

"This was a very vicious, brutal, nasty, mean beating of a man," Scott said before setencing each youth to the lengthy terms. Each will be eligible for parole in 16 years.