Find and kill active connections to Database

select DB_NAME(dbid), ('kill ' + convert(nvarchar(10), spid) ) as kill_statement, * 

from sys.sysprocesses where DB_NAME(dbid) = 'DBNAME'
--or:

DECLARE @SQL nvarchar(max) 
SELECT @SQL=COALESCE(@SQL,'') +'Kill '+CAST(spid AS nvarchar(10))+ '; '  
FROM sys.sysprocesses WHERE DB_NAME(dbid) = 'DBNAME'