Example of Soft (but highly useful) Information Available on the Internet.
Refer: Structure Determination by Powder Diffractometry Round Robin [http://fluo.univ-lemans.fr:8001/SDPDRR/]
Searching on the molecular formula for sample 2. using "Inference find"
C22H24N2O8 - and C22H24N2O8.HCL) reveals not only the name and connectivity in pages such as
TR-344 Toxicology and Carcinogenesis Studies of Tetracycline Hydrochloride
(CAS No. 64-75-5) in F344/N Rats and B6C3F1 Mice (Feed Studies)
but also a starting molecule in MDL Mol File format
- - - - Gif from Webpage - - - - - Chemdraw derived MDL Mol file Directly in Rasmol
Compared to Connectivity Derived from Expensive Commercial Database