According to the ACS style guide [1, p. 240]
Chemical names are not capitalized unless they are the first word of a sentence or
are part of a title or heading. Then, the first letter of the syllabic portion is capitalized, not the locant, stereoisomer descriptor, or positional prefix.
Therefore, the following capitalization is correct:
3,5-Dinitrosalicylic acid can reduce sugars with aldehyde or ketone functionality.
Reference
- The ACS Style Guide: Effective Communication of Scientific Information, 3rd ed.; Coghill, A. M., Garson, L. R., Eds.; American Chemical Society; Oxford University Press: Washington, DC; Oxford; New York, 2006. DOI: 10.1021/ed083p1603.1, ISBN 978-0-8412-3999-9.