How to get agent name?

I write a reactor  as the following image ,I use the method getAgent(),I can get the agent count .but i can not use getPreferredIUPACName() ,it has exception.How can I get "R2"?Thanks!

Exception information:

chemaxon.marvin.plugin.PluginException: chemaxon.marvin.io.MolExportException: Name generation failed: chemaxon.marvin.io.formats.name.nameexport.IUPACNamer$UnsupportedError: Naming is not supported on this structure: unknown pseudo-atom #134

java code:

int num=mol.getAgentCount();

  for(int jj=0;jj<num;jj++){

  plugin.setMolecule(mol.getAgent(jj));

  plugin.run();

   String preferredIUPACNames  = plugin.getPreferredIUPACName();

  }

The agent cannot be named, because it contains an unknown pseudo-atom (see the error message: "Naming is not supported on this structure: unknown pseudo-atom #134"). I suggest you to catch the PluginException in the for loop, and use SMARTS or some other format instead of name if the exception is thrown.

mol.getAgent(jj).toFormat("smarts"); 

Zsolt

mol.getAgent(jj).toFormat("smarts"); 

Thanks.I have tried all Molecule formats,but I  can not get "R2".and I find another problem that ：if the structure has pseudo-atom ,use  "plugin.getPreferredIUPACName()", also throw exception.

The agent ("R2") seems to be an R-group. Without R-group definition (I can't see it on the image) it's absolutely useless. If there is an R-group definition in the molecule, then you can enumerate it with the Markush Enumeration plugin, and then use the result of the enumeration for generating the agent name.

Zsolt