adoc to pdf conversion is nowadays related mainly to export of Asciidoctor documents to PDF format, something that can be easily done with the program.
Another type of this conversion might be related to Authentica Secure Office, but unless there is a way in the original software to export ADOC files as PDF document, you probably cannot convert adoc to pdf by any means. Considering ADOC format was a specially designed as protected document, it would make sense that it is not possible to convert it at all.