code: static void updateAromaticTypesInSixMemberRing(int[] cycle, String[] symbs) {
          for (final int v : cycle) {
              if (NCN_PLUS.equals(symbs[v]) || "N+=C".equals(symbs[v]) || "N=+C".equals(symbs[v]))
                  symbs[v] = "NPD+";
              else if ("N2OX".equals(symbs[v]))
                  symbs[v] = "NPOX";
              else if ("N=C".equals(symbs[v]) || "N=N".equals(symbs[v]))
                  symbs[v] = "NPYD";
              else if (symbs[v].startsWith("C")) symbs[v] = "CB";
          }
      }
docs: Update aromatic atom types in a six member ring. The aromatic types here are hard coded from
  the 'MMFFAROM.PAR' file.
  
  @param cycle 6-member aromatic cycle / ring
  @param symbs vector of symbolic types for the whole structure