Gleasons Gym, three blocks to the south of Madison Square Garden, is a version of hell to those who care little for the crunch of leather against mandible, for those who prefer other tints to the dank ochre of a ring canvas gone dark and sour from resin and sweat and blood.

To an A.J. Leibling, though, places like Gleasons were havens in "the realms of higher intellection;" such gyms, populated by professors named Sonny and Angie and Pep, continue to be Boxiana's Colleges of Hard Knocks.

Roberto Duran, who received his own boxing education in the streets of Panama, has endured a kind of adult re-education course at Gleasons preparing for Thursday night's World Boxing Association junior middleweight fight at Madison Square Garden against the young but formidable champion, Davey Moore. (The bout will be shown on closed-circuit at Charles Town Turf Club at about 10.)

If Duran wins, and he is not favored to do so, he will become the seventh fighter to hold three titles. He has held the lightweight and welterweight titles.

Duran forsook his welterweight belt and his image as the most intimidating puncher in the game when, in November, 1980, he quit his bout against Sugar Ray Leonard with a wave of his glove and a request of "no mas." That cry of "no more" has become the quitter's badge that Duran seems determined to rebuke.

At Duran's training camp at Great Gorge in McAfee, N.J., and at his recent workouts at Gleasons, old fight hands like matchmaker Teddy Brenner say Duran has regained the desire that some used to regard as "animal." The flashing eyes are intense once more.

In the past, Duran's discipline in training camp was suspect. He was prone to bouts with the fork and knife. But against Moore, Duran's handlers say he will fight two pounds under the 154-pound limit, an obvious expression of renewed discipline.

"I'm in better condition than I have been in a couple of years," Duran told United Press International. "I never really got myself in great shape for the past few fights. I realize the importance of this fight."

Immediately after the second Leonard fight, Duran was sullen and performed like a tired club fighter, ready to retire. He lost to an undistinguished British boxer, Kirkland Laing, and eked out a paltry victory over one Jimmy Batten. Rebuked by many of his countrymen, Duran retreated into mediocrity.

But in Los Angeles four months ago, on the night before the Super Bowl, Duran fought impressively against a proven boxer, Pipino Cuevas. On that night, Duran looked as relentless as he had the night he defeated Leonard in 15 rounds in Montreal. Duran, who has learned every nuance there is while compiling a record of 75-3-1, was his savvy self on the way to dispatching Cuevas in the fourth round.

He used his forehead, elbows and feet almost as effectively as his hands, to back Cuevas against the ropes from the opening bell. Cuevas landed no more than a half-dozen blows before being escorted from the arena. After the fight, Duran vowed a victory over Moore, though it was apparent that his true nemesis, Leonard, would never face him again, having retired.

Moore is just 24, with only a dozen victories in as many professional fights. Most boxing people consider Thomas Hearns, who holds the World Boxing Council's version of the junior middleweight championship, to be the true titlist, but Moore is well regarded for so young a fighter. He won the title in January in Tokyo against Tadashi Mihara, and has had succesful defenses against Charley Ware, Ayub Kalule and, on the same night as Duran's victory over Cuevas, Gary Guiden.

Moore, who has knocked out his last nine opponents, is a tough counterpuncher and will not try to move around the ring much against Duran. "I don't think it will be all that tough a fight," Moore said. "He passed his peak a long time ago and I'm still getting close to reaching mine."

Duran has said he will retire if he loses, but he has promised to continue his comeback by defeating Moore and facing, possibly, Hearns or Marvelous Marvin Hagler, the middleweight champion. Duran, who has switched his alliance from Don King to Arum and is working with a much smaller entourage than usual, is confident his 17 years of ring experience will be the difference. And, as the weeks in camp have shown, Duran is hungry for a third title and a cleared reuptation.

"Moore can do it all, he's the best in years," Brenner said. "A guy like Duran's gonna give him a test, though."