The palatial home, at 8 East 62nd Street, was the most expensive closed sale in New York City this month. Other closings included one of Brooklyn’s priciest properties.

After more than six years and a few price cuts, the real estate developer Keith Rubenstein finally sold his lavish, Beaux-Arts mansion on the Upper East Side.

The imposing limestone building, at 8 East 62nd Street, with rooftop views of nearby Central Park, was bought by an anonymous buyer for $48 million. It was New York City’s most expensive closed sale in September, though deeply discounted from the initial $84. 5 million asking price in early 2016.

Mr. Rubenstein, who runs the development company Somerset Partners, and his wife, Inga Rubenstein , a Russian-born former model and serious art collector, paid $35 million for the home in 2007. They poured millions more into top-to-bottom, opulent renovations — like Hermès leather walls in the billiards room and a lower-level spa that has a gym, massage room, cold-plunge pool plus sauna.

Throughout the city, several other notable houses also changed ownership during the month. Some sold faster than others.

It took the fashion designer Zoran Ladicorbic almost seven years to find a buyer for his unusual TriBeCa property, a townhouse that connects to a third-floor loft apartment across the street via the only private skybridge within the city. The combined sale was $24 million.

In Turtle Bay, Olivier Sarkozy, a banker and the half brother of the former French president Nicolas Sarkozy , sold his double-wide townhouse a year after listing it, and after his divorce from Mary-Kate Olsen , the former child actor and now a fashion designer. In Brooklyn Heights, the cryptocurrency executive Joseph Lallouz and his wife, Chloe Thevenoz , snapped up the townhouse with a separate carriage house, paying above selling price.

Prominent apartment transactions included a brand-new penthouse in Hudson Yards that sold for $35 million — the month’s second-most expensive sale — and a Fifth Avenue penthouse purchased by the fashion designer Reed Krakoff, formerly of the luxury brand Coach, and his wife, Delphine Krakoff , an interior designer, from the civil rights lawyer Eleanor Jackson Piel.

The particular month’s top sale , the Upper East Side estate that closed at $48 million, is as big as a typical boutique hotel — and probably with a lot more amenities.

Built in the early 1900s, the structure extends 14, 825 square feet over six levels, counting the ground-floor spa, where there’s also a wine cellar with custom oak millwork.

It has five main bedrooms, seven full bathrooms and five powder rooms.

Tina Fineberg for The New York Times

The grand entrance gallery, which featured some of the Rubensteins’ vast collection of oversize contemporary art, has restored malachite and mosaic floors; a fireplace with a large carved mantel, one of four hearths in the house; and a marble spiral staircase with decorative wrought-iron and brass balustrades.

Besides the leather-lined billiards room, there’s also a bedroom-turned-smoking room, equipped with an exhaust system, a media room with a wet bar, along with a study off an extra-large kitchen that features a breakfast area and butler’s pantry.

One of the best parts of the house, at least for this time of year, is the landscaped rooftop terrace, which has a full outdoor kitchen, along with areas carved out for dining and lounging.

The new owner purchased the house, which was most recently listed at $55 million, through the limited liability company Aston Fifth.

The nondisclosure agreement prevented the particular seller’s broker, Adam D. Modlin of the Modlin Group, from further discussing the transaction.

The skybridge property in TriBeCa, offered by Mr. Ladicorbic, included a three-story, 25-foot-wide property at 9 Jay Street, closing at $20 mil, and an one-bedroom, one-bathroom loft combined from two units at 67 Hudson Road, at $4 million.

The frequently photographed windowed footbridge, suspended over Staple Street, was erected in 1907 for the expanding downtown clinic of New York Hospital, now known as NewYork-Presbyterian Hospital.

Mr. Ladicorbic, whose fashion brand is called Zoran , bought the townhouse in 1985 with a $499, 000 mortgage, and the Hudson Street apartments reportedly a few months later. He had used the townhouse as a work space and the loft as a residence. He first put the properties, totaling more than 8, 000 square feet, including a good unfinished rooftop terrace, on the market in 2015 for $50 million. Its most recent sale price was $26 million, according to Sotheby’s International Realty, the listing broker.

The buyer was the David C. Butterfield and Alfonso Deb. Rubio Memorial Foundation, a charitable organization based in Aspen, Colo.

Dimitrios Kambouris/Getty Images

The townhouse sold by Mr. Sarkozy is at 226-228 East 49th Street, between Second and Third Avenues in the Turtle Bay Gardens Historic District . It sold for nearly $10. 3 million, below the preliminary $11. 5 million asking price in August 2021.

Mr. Sarkozy never actually lived there. He bought the house from the artist David Deutsch for $13. 5 mil in 2014, shortly before marrying Ms. Olsen. But the major renovation that he and Ms. Olsen had planned stalled, and the couple divorced last year.

The house, which contains five wood-burning fireplaces and original millwork throughout, had been marketed as is, or as the Corcoran listing noted, “for endless options dependent on your needs. ”

The new owner, the limited liability company Flying Cloud Properties, will certainly have plenty to work with: The house — 38 feet wide with about 8, 700 square feet of space over five floors — is actually two buildings that were combined in the 1910s by the railroad heiress Charlotte Hunnewell Sorchan to create her primary residence.

Residents of the Turtle Bay Gardens enclave share a common garden filled with fountains, shrubbery and trees. And the proprietor of 226-228 East 49th Street has another coveted amenity: an one-car garage.

Within Brooklyn Heights , Mister. Lallouz and Ms. Thevenoz paid $18. 3 million for a five-story townhouse with a separate carriage house, at 88 Remsen Street. This was above the most recent $15 mil asking price and among the borough’s most expensive residences ever marketed.

The seller was Andrew Vogel, whose family business, Intership, provides offshore accommodations on international drilling projects.

The home, with a classic front stoop, has six bedrooms, eight full bathrooms and three powder rooms; its current configuration includes a garden-floor residence and a large top-floor home office.

Meticulously restored and updated, the home has many original architectural flourishes, like the inlaid wood floors, crown moldings and three fireplaces on the parlor floor plus updates, including a media and games room on the lower level.

There are two terraces — off the kitchen and a fifth-floor bedroom — and a rooftop deck with views of New York Harbor. Behind the house is a landscaped garden where you’ll find the one-bedroom, one-bathroom carriage house, replete having a full kitchen and grotto-style lower-level with a screening space.

And there’s that garage, too.

Mr. Lallouz is a founder of Bison Trails, the blockchain infrastructure platform that was acquired last year by the crypto exchange Coinbase.

Gabby Jones for The New York Times

Now for the apartment sales. The sponsor penthouse at 35 Hudson Yards, which sold for 35 dollars million, takes up an entire floor, encompassing 10, 171 square feet. The Corcoran listing called it a “compound in the sky. ” The unit has five bedrooms and 8 and a half bathrooms, among its many rooms, along with a 454-square-foot terrace off the great room. Then there are the amazing picturesque views — of the Hudson River, Midtown skyline, Central Park and beyond — through just about every corner. The buyer was your aptly named limited liability company Sky Palace.

Across town, the Krakoffs paid nearly $6 million for their Central Park-facing penthouse at 1115 Fifth Avenue, between East 92nd and 93rd Streets. The house has three bedrooms plus three and a half bathrooms, and pretty vistas, too. On its east side is really a terrace that provides scenic urban views; on the west, with the oversize windows, it almost feels like a country home overlooking the Central Recreation area Reservoir.