The Manahattan-based developer angling to erect an 81-story skyscraper in the heart of downtown Denver is no longer under contract to buy land where the building is supposed to go, the property’s owner said Monday.

But the developer’s attorney said the situation is a misunderstanding and his employer fully intends to buy the land and build the building.

The Six Fifty 17 project would be the tallest building in Denver as proposed, reaching a height of 1,000 feet. It would bring a combined 705,045 square feet of hotel, condo, parking and amenities space to the corner of 17th and California streets, according to documents that representatives of developer Greenwich Realty Capital submitted to city planners this month.

But Greenwich will have to make some land purchases before it can break ground on the $371 million project.

Greenwich’s contract to buy a 25,000-square-foot lot on the corner now occupied by an asphalt parking lot, where the building would sit, has expired without a deal, according to Buzz Geller, chief executive of Paradise Investment Properties, the company that owns it.

“What happened is (Greenwich) failed to close,” Geller said. “When someone fails to close, my experience in the real estate business tells me the deal is dead.”

Greenwich partners Michael Ursini and Stephen Drew were unavailable Monday because they are meeting with new capital partners for the project. But their Denver-based attorney, Thomas Ragonetti, speaking on their behalf, told The Denver Post the contract expiration was a misunderstanding and it does not reflect any change in his client’s plans.

Greenwich has been “religiously making their extension payments” on the contract, Ragonetti said, and believed the latest extension was valid through the end of February. While that was not the case, he said Greenwich is committed to buying from Geller.

“Their intention is to get back under contract and they are intending to move forward with the project,” Ragonetti said.

Denver property records show Paradise bought the land in 2002 for $3.5 million.

Geller mentioned Greenwich was “having trouble with the outlying parcels” it was seeking to add to the project site.

The concept plans submitted to the city this month show that the tower would also take up a 6,262-square-foot lot at 1630 California St. That land, located just behind the Paradise lot, also is used for parking today. It is owned by Massachusetts-based Franklin Street Properties, city records show.

Greenwich managing partner Michael Ursini told BusinessDen last week that his company had been talking to the owner for months about obtaining it.

Officials with Franklin Street did not return calls seeking comment Monday.

Greenwich contracted architects Crown Architecture and Consulting and Denver-based Davis Partnership, submitted a building concept to the city in mid-February. The 15-page document shows the base of the building occupying all of the Paradise and Franklin-owned land.

The plans also show Greenwich included the 6,262 square feet of land owned by Franklin and roughly 4,007 square feet of space that would be gained by privatizing the public alleyway the runs along the east side of the property when calculating the potential square footage of the proposed building.

It’s not uncommon for developers to enter the site development process with the city before finalizing a land purchase, Denver Community Planning and Development spokeswoman Andrea Burns said in an email Monday. But before earning city approval a finalized site plan, “must be signed by any and all owners of the property,” she said.