1.2 Cyclic Systems
59
e) The next priority criterion deals with ring size. If the most senior element is found in the larger as well as in the smaller ring the larger ring
wins as parent component, regardless of the nature and number of other
hetero elements present, with the exception of nitrogen, of course (see b).
4H- [1,3,2]Dioxasilolo[ 4,5-c ]pyran
f) If the assignment is still ambiguous the larger number of (any) hetero
elements becomes decisive.
[1,3] Oxaphospholo [4,5-d] [1,3,2] oxarsaborole
g) If criterion f) is insufficient, the greater variety of hetero atoms becomes valid, if necessary with respect to the "a" term Table 4 (p. 52).
N
N
I Pyrimido[4,5-b][I,4]azasiline
CJC
~
::-...
h N3
Si
H
8~0""'02
1
-I
.I 6H,8H-[1,2,4]Dioxazino[4,3-c][I,3,2]oxazaphosphinine
0, /N~
P 5
H
h) Next, the greatest number of senior atoms according to Tables 4, 20 is
to be considered.
[1,2,7] Oxadiazepino [4,5-fl [1,3,5] dioxazepine
59
e) The next priority criterion deals with ring size. If the most senior element is found in the larger as well as in the smaller ring the larger ring
wins as parent component, regardless of the nature and number of other
hetero elements present, with the exception of nitrogen, of course (see b).
4H- [1,3,2]Dioxasilolo[ 4,5-c ]pyran
f) If the assignment is still ambiguous the larger number of (any) hetero
elements becomes decisive.
[1,3] Oxaphospholo [4,5-d] [1,3,2] oxarsaborole
g) If criterion f) is insufficient, the greater variety of hetero atoms becomes valid, if necessary with respect to the "a" term Table 4 (p. 52).
N
N
I Pyrimido[4,5-b][I,4]azasiline
CJC
~
::-...
h N3
Si
H
8~0""'02
1
-I
.I 6H,8H-[1,2,4]Dioxazino[4,3-c][I,3,2]oxazaphosphinine
0, /N~
P 5
H
h) Next, the greatest number of senior atoms according to Tables 4, 20 is
to be considered.
[1,2,7] Oxadiazepino [4,5-fl [1,3,5] dioxazepine