| 201/00 | Preparation, separation, purification, or stabilisation of unsubstituted lactams |
| 201/02 | Preparation, separation, purification, or stabilisation of unsubstituted lactams Preparation of lactams |
| 201/04 | Preparation, separation, purification, or stabilisation of unsubstituted lactams Preparation of lactams from or via oximes by Beckmann rearrangement |
| 201/06 | Preparation, separation, purification, or stabilisation of unsubstituted lactams Preparation of lactams from or via oximes by Beckmann rearrangement from ketones by simultaneous oxime formation and rearrangement |
| 201/08 | Preparation, separation, purification, or stabilisation of unsubstituted lactams Preparation of lactams from carboxylic acids or derivatives thereof, e.g. hydroxy carboxylic acids, lactones, nitriles |
| 201/10 | Preparation, separation, purification, or stabilisation of unsubstituted lactams Preparation of lactams from cycloaliphatic compounds by simultaneous nitrosylation and rearrangement |
| 201/12 | Preparation, separation, purification, or stabilisation of unsubstituted lactams Preparation of lactams by depolymerising polyamides |
| 201/14 | Preparation, separation, purification, or stabilisation of unsubstituted lactams Preparation of salts or adducts of lactams |
| 201/16 | Preparation, separation, purification, or stabilisation of unsubstituted lactams Separation or purification |
| 201/18 | Preparation, separation, purification, or stabilisation of unsubstituted lactams Stabilisation |
| 203/00 | Heterocyclic compounds containing three-membered rings with one nitrogen atom as the only ring hetero atom |
| 203/02 | Heterocyclic compounds containing three-membered rings with one nitrogen atom as the only ring hetero atom Preparation by ring-closure |
| 203/04 | Heterocyclic compounds containing three-membered rings with one nitrogen atom as the only ring hetero atom not condensed with other rings |
| 203/06 | Heterocyclic compounds containing three-membered rings with one nitrogen atom as the only ring hetero atom not condensed with other rings having no double bonds between ring members or between ring members and non-ring members |
| 203/08 | Heterocyclic compounds containing three-membered rings with one nitrogen atom as the only ring hetero atom not condensed with other rings having no double bonds between ring members or between ring members and non-ring members with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached to the ring nitrogen atom |
| 203/10 | Heterocyclic compounds containing three-membered rings with one nitrogen atom as the only ring hetero atom not condensed with other rings having no double bonds between ring members or between ring members and non-ring members with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached to the ring nitrogen atom Radicals substituted by singly bound oxygen atoms |
| 203/12 | Heterocyclic compounds containing three-membered rings with one nitrogen atom as the only ring hetero atom not condensed with other rings having no double bonds between ring members or between ring members and non-ring members with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached to the ring nitrogen atom Radicals substituted by nitrogen atoms not forming part of a nitro radical |
| 203/14 | Heterocyclic compounds containing three-membered rings with one nitrogen atom as the only ring hetero atom not condensed with other rings having no double bonds between ring members or between ring members and non-ring members with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached to the ring nitrogen atom with carbocyclic rings directly attached to the ring nitrogen atom |
| 203/16 | Heterocyclic compounds containing three-membered rings with one nitrogen atom as the only ring hetero atom not condensed with other rings having no double bonds between ring members or between ring members and non-ring members with acylated ring nitrogen atoms |
| 203/18 | Heterocyclic compounds containing three-membered rings with one nitrogen atom as the only ring hetero atom not condensed with other rings having no double bonds between ring members or between ring members and non-ring members with acylated ring nitrogen atoms by carboxylic acids, or by sulfur or nitrogen analogues thereof |