Sometimes Espacenet is down for some reason. You can try
www.uspto.gov . The patents are in TIFF format and you need a TIFF browser plugin to view them. See what I posted in this thread for details.
Post 68327 (missing)
(Antoncho: "Reduction of nitroalkenes with SnCl2", Novel Discourse)Note: any US patents issued 17 years before today are expired and are in the public domain. Patents can't be renewed, but improvements are patentable. Sometime in the early 90's they changed the law so that any patent issued since then expires 20 years from its filing date, but since that's less than 20 years ago from the time this was posted, you don't have to worry about it for now. Some (very few) patents can be extended. Usually they're on drugs since development and approval by the FDA takes a lot of time. The ones I've seen were issued to the big drug companies (blue chips on wall street), and usually aren't extended by more than a couple years. The chemistry we're interested in here has been around since the 1800's and early 1900's. Most of the patents I've seen related to the chemistry discussed here have been expired for a long time.
Also, if you're suspected of infringing on someone's US patent, the feds aren't going to come after you and arrest you. A US patent just gives the owner(s) or assignee(s) the right to exclude others from making and using the invention, which is decided in court (ie. prosecution depends entirely on the assignee(s)). If they take you to court and they win and you still refuse to stop infringing on their patent then maybe the police will come after you. The first thing most people (usually companies) do when accused of infringing on someone's patent is to say the patent is invalid and start looking for references to invalidate it.
