Heterocyclic compounds containing four-membered rings having one oxygen atom as the only ring hetero atoms [2]
305
/
02
•
not condensed with other rings [2]
305
/
04
•
•
having no double bonds between ring members or between ring members and non-ring members [2]
305
/
06
•
•
•
with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached to the ring atoms [2]
305
/
08
•
•
•
with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring atoms [2]
305
/
10
•
•
having one or more double bonds between ring members or between ring members and non-ring members [2]
305
/
12
•
•
•
Beta-lactones [2]
305
/
14
•
condensed with carbocyclic rings or ring systems [2]
307
/
00
Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom [2]
307
/
02
•
not condensed with other rings [2]
307
/
04
•
•
having no double bonds between ring members or between ring members and non-ring members [2]
307
/
06
•
•
•
with only hydrogen atoms or radicals containing only hydrogen and carbon atoms, directly attached to ring carbon atoms [2]
307
/
08
•
•
•
•
Preparation of tetrahydrofuran [2]
307
/
10
•
•
•
with substituted hydrocarbon radicals attached to ring carbon atoms [2]
307
/
12
•
•
•
•
Radicals substituted by oxygen atoms [2]
307
/
14
•
•
•
•
Radicals substituted by nitrogen atoms not forming part of a nitro radical [2]
307
/
16
•
•
•
•
Radicals substituted by carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals [2]
307
/
18
•
•
•
with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms [2]
307
/
20
•
•
•
•
Oxygen atoms [2]
307
/
22
•
•
•
•
Nitrogen atoms not forming part of a nitro radical [2]
307
/
24
•
•
•
•
Carbon atoms having three bonds to hetero atoms with at the most one bond to halogen [2]
307
/
26
•
•
having one double bond between ring members or between a ring member and a non-ring member [2]
307
/
28
•
•
•
with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached to ring carbon atoms [2]
307
/
30
•
•
•
with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms [2]
307
/
32
•
•
•
•
Oxygen atoms [2]
307
/
33
•
•
•
•
•
in position 2, the oxygen atom being in its keto or unsubstituted enol form [5]
307
/
34
•
•
having two or three double bonds between ring members or between ring members and non-ring members [2]
307
/
36
•
•
•
with only hydrogen atoms or radicals containing only hydrogen and carbon atoms, directly attached to ring carbon atoms [2]
307
/
38
•
•
•
with substituted hydrocarbon radicals attached to ring carbon atoms [2]
307
/
40
•
•
•
•
Radicals substituted by oxygen atoms [2]
307
/
42
•
•
•
•
•
Singly bound oxygen atoms (two oxygen atoms bound to the same carbon atom C 07 D 307/46) [2]
307
/
44
•
•
•
•
•
•
Furfuryl alcohol [2]
307
/
45
•
•
•
•
•
•
Oxygen atoms acylated by a cyclopropane containing carboxylic acyl radical, e.g. chrysanthemumates [3]
307
/
46
•
•
•
•
•
Doubly bound oxygen atoms, or two oxygen atoms singly bound to the same carbon atom [2]
307
/
48
•
•
•
•
•
•
Furfural [2]
307
/
50
•
•
•
•
•
•
•
Preparation from natural products [2]
307
/
52
•
•
•
•
Radicals substituted by nitrogen atoms not forming part of a nitro radical [2]
307
/
54
•
•
•
•
Radicals substituted by carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals [2]
307
/
56
•
•
•
with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms [2]
with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached to carbon atoms of the hetero ring [2]
307
/
80
•
•
•
•
Radicals substituted by oxygen atoms [2]
307
/
81
•
•
•
•
Radicals substituted by nitrogen atoms not forming part of a nitro radical [2]
307
/
82
•
•
•
with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to carbon atoms of the hetero ring [2]
307
/
83
•
•
•
•
Oxygen atoms [2]
307
/
84
•
•
•
•
Carbon atoms having three bonds to hetero atoms with at the most one bond to halogen [2]
307
/
85
•
•
•
•
•
attached in position 2 [2]
307
/
86
•
•
•
with an oxygen atom directly attached in position 7 [2]
