You would have to quote the string, but simplest way is putting JSON data in a file and asking cURL to read from it:
C:\WINDOWS\system32>curl.exe -D- -u fred:fred -X POST --data @data_to_send.json -H "Content-Type: application/json" http://ABCD.com:XXXX/rest/api/2/issue/
Note the @
before file name.