$re = '~"[^"]+":\s*"[^"]+"[,}]\s*(*SKIP)(*FAIL)|(?<![,:])"(?![:,]\s*["}])~';
$str = 'json_str = \'\'\'{"id":"9","ctime":"2018-02-13","content":"abcd: "efg.","hots":"103b","date_sms":"2017-11-22"}\'\'\'';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php