MIDTOWN Losing its flea market By STEVE CUOZZO

BIG changes are coming to West 42nd Street between Sixth and Seventh avenues. The miserable-looking south midblock is finally going to be redeveloped this year, and the ugly-duckling "Building That Times Square Forgot" to its east will soon come down. Marwan Dalloul, principal of American Properties, says demolition of the flea market between Bush Tower at 130 W. 42nd St. and 1466 Broadway will start this spring. The site is directly across from where Douglas Durst's giant One Bryant Park is now going up.

"If everything goes well, we should be starting by April or May" on 140 W. 42nd St., the office and retail project he's had on the drawing board for several years, Dalloul said. American Properties owns Bush Tower as well as the low-rise discount bazaar next door. The new 140 W. 42nd, designed by architects Gruzen Samson, will have 180,000 square feet, including 12,000 square feet of stores. It was designed in 2004 but Dalloul was waiting for the right market.

The whole of 42nd Street is booming, nowhere more so than between Madison Avenue and Broadway where more than 6 million square feet of new offices have been built and mostly leased in 6 different towers over the past few years. Among the success stories is 275,000-foot 505 Fifth Ave., which Axel Stawski built on spec and is now mostly leased to anchor tenant CIT and other financial firms. Dalloul, who also plans to build before he signs tenants, said, "Stawski's project was definitely inspiring in some ways. We can only hope to repeat the success he had. He timed it perfectly, and the timing is good today, too."

Dalloul is confident about financing but declined to be specific. He said the only thing that might delay construction would be engineering issues involved with connecting the new building with Bush Tower. Meanwhile, dorky, six-story 124 W. 42nd St. just east of Bush Tower will finally come down. Sources say that Equity Office Properties, which bought the former Verizon tower at 1095 Sixth Ave. at the corner, is buying the long vacant eyesore from the Kassover family.

The purchase will give Equity elbow room to expand the plaza at the foot of 1095 Sixth. It will get rid of a blight next door to the tower on which it's about to spend $260 million for a new façade and capital improvements.