Are there alternatives to O-[(Diaminomethylene)amino]-L-homoserine sulfate (CAS: 2219-31-0) in synthesis?

There are alternative reagents and starting materials that can be used in the synthesis of compounds similar to O-[(Diaminomethylene)amino]-L-homoserine sulfate (CAS: 2219-31-0). For instance, using other amino acids or their derivatives can offer similar functional groups for modification. Common alternatives include L-serine or D-serine, which can be modified to create functional analogs with similar chemical properties.