Last Thursday, The New York Observer’s website reported that the New York’s most expensive listing, an $80 million, 5,276-square-foot, 14-foot-tall, 9.5-room penthouse 15 CPW had come off the market. However, a new titanic listing has taken its place. According to two sources, an 18th-floor duplex bought last March for only $23.5 million, with about 5,870 square feet indoors and 1,112 square feet of terrace space, is quietly asking $75 mill. It’s next door to the better-known duplex that a biotech venture capitalist reportedly put on the market this year for $90 million (both duplexes are unofficial listings that don’t show up on popular real estate sites like StreetEasy-after last week’s disappearance of that $80 million penthouse, that site now shows a $30 million property as the biggest on the market in the famed building.) It’s not clear how long this fresh duplex has been available, or for how long it’s been asking $75 million, and the broker who is said to be handling it, Susan James, has not replied to The Observer’s enquiries. The apartment was bought under the name Ullman Family Partnership, which bought a high-floor unit at Trump International for $8 million in 2003 and sold another there for $6.4 million in 2004. Upon further investigation, New Jersey billing addresses and a signature on old deeds connect the 15 Central Park West duplex to the drug benefits kingpin Richard O. Ullman. In 2002, he reportedly sold his National Prescription Administrators firm to the country’s third largest drug benefits group for over $500 million.