Signage is up at 364 Union Street, a brownstone conversion project in Carroll Gardens. Sales will launch this spring, and the website is now up. There will be five condo units — four three-bedroom units and one garden duplex, with prices ranging from $1.15 to $1.6 million. Sales will launch this spring, and the website is now up. Over the fall a story came out about these developers, East River Partners, who buy up multi-families in Park Slope and Carroll Gardens and renovate them as small condo developments. So far they’ve had lots of success, with their units going at ask or above.