Neosalvarsan
Other names	Sodium 3,3'-diamino-4,4'-dihydroxyarsenobenzene-N-formaldehydesulfoxylate; Neoarsphenamine
Identifiers
CAS number	457-60-3
PubChem	9980
SMILES	C1=CC(=C(C=C1[As]=[As]C2=CC(=C(C=C2)O)NCS(=O)[O-])N)O.[Na+]
Properties
Molecular formula	C13H13As2N2NaO4S
Molar mass	466.15 g/mol
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Neosalvarsan is a synthetic chemotherapeutic that is an organoarsenic compound. It became available in 1912 and superseded the more toxic and less water-soluble salvarsan as an effective treatment for syphilis. Because both of these arsenicals carried considerable risk of side-effects, they were replaced for this indication by penicillin in the 1940s.

Both salvarsan and neosalvarsan were developed in the laboratory of Paul Ehrlich in Frankfurt, Germany. Their discoveries were the result of the first organized team effort to optimize the biological activity of a lead compound through systematic chemical modifications.^[1] This scheme is the basis for most modern pharmaceutical research. Both salvarsan and neosalvarsan are prodrugs — that is, they are metabolised into the active drug in the body.

[edit] Structure

The structure of salvarsan, and of this derivative, was once believed to feature an As=As bond (as shown in the figure). In 2005, salvarsan was shown to be a mixture of the cyclic trimer and a pentamer.^[2][3] The revised structure features As-As single bonds, not double bonds.

[edit] References

1. ^ Strebhardt K, Ullrich A (May 2008). "Paul Ehrlich's magic bullet concept: 100 years of progress". Nat. Rev. Cancer 8: 473. doi:10.1038/nrc2394. PMID 18469827. 
2. ^ "accsnet.ne.jp". http://www1.accsnet.ne.jp/~kentaro/yuuki/mow/0501/salvarsan.html. Retrieved 2007-08-25. 
3. ^ Lloyd NC, Morgan HW, Nicholson BK, Ronimus RS (2005). "The composition of Ehrlich's salvarsan: resolution of a century-old debate". Angewandte Chemie International Edition in English 44 (6): 941–4. doi:10.1002/anie.200461471. PMID 15624113.