I ran a reaction the other day which gave me two very similar products. That's not so uncommon, but this one really shouldn't have been able to do that. (For the chemists in the audience, these two so similar, in fact, that the usual LC/MS conditions only showed one peak. NMR tells you different, though, and a painstaking multiple-elution TLC in some nonstandard solvent mixtures resolves the two spots).
I thought about the problem a bit, and decided that the first thing to do was to check my starting material. And there they were: two very similar starting materials, together in the same jar. Mind you, there's only one structure on the label. No wonder the stuff was so sticky. I'd received the Special Extended Edition without knowing it - odds are, the supply company sent it to me without knowing it, either, although that'll change when they get my e-mail. One of the components, anyway, seems to be the right stuff, so I suppose it could be worse.
This happens more often than it should, often enough that every working chemist has a similar story or two. And it doesn't correlate that well with the size or renown of the company you're ordering from, since everyone sources material from all over the place. Little mom-and-pop operations have sent me plenty of fluffy, flawless stuff, while Aldrich has on occasion mailed me goo. (On another occasion they mailed me a perfectly empty sealed ampoule with a label on it, but since the label didn't read "Air", I thought I had reason to complain). That doesn't mean that reputations don't vary. Even though they're now part of the same company as Aldrich and Sigma, those Swiss fanatics at Fluka do this sort of thing to you comparatively less often than their cohorts.
Not all the unopened slime you encounter is necessarily the fault of the company that shipped it. Some things just aren't stable, or at least aren't so stable in the back of an unventilated truck or sitting out in the sun on a loading dock. And the longer it is after an order's been received, the more the problem is likely to be with the receiver. A look at the condition of the vials in a drug company's compound repository will convince anyone that the kinds of molecules we like may not have indefinite shelf lives.
In this case, it's going to be easier to clean up the starting material and run the reaction again than it would be to clean up my dueling products. Easier yet would be to get a bottle of the right stuff from the supplier, but this one isn't exactly a high-volume compound, and I suspect that it's all the same nasty batch on their shelves. Worth a try, though. And thus does science stagger on.