I've ran into a few chemists out there that wonder if aryl nitrostyrenes are really all that stable. Reference to Rhodium states that nitropropenes are really only stable for a week or so before decomp. I've had similar questions about the nature of the same principle applying to the nitrostyrenes. Would there be trimers present in an almost 4 year old product of nitrostyrene? Here's what a certain pstain did...

A small milligram sample of pumpkin orange 2,5-dimethoxynitrostyrene crystals were removed from storage after 4 years in a tight glass mason jar sitting in roughly room temp conditions in a dark drawer. The original sample came from a batch that was prepared from the henry reaction of the aryl aldehyde with nitromethane and an ammonium acetate catalyst without further recrystallization.

This sample was applied to a melting point block. At exactly 112-113C the sample quickly melted into a dark, almost brown liquid conclusive with the literature MP of 112-113C...couldn't have been more spot on.  Just thought I'd share for those interested.

It's listed in PIHKAL at 119-120C before recrystallisation and 120-121C recrystallised from ethyl acetate. Bethlab MSDS lists it at 112-113C while quoting a litterature value of 116-120C.

Toady was just wondering this himself actually. Beat him to posting though. A sample of 2,5-dimethoxy-4-methyl-beta-nitrostyrene has been sitting out in the air for a while, a couple of months, and the color has noticeably become more orange. It was rextylized from methanol and washed with 2H2O several times until bright, clear yellow, free of orange tints, left out for a couple of months, and around the edges and on exposed surfaces here and there of crystals the orange color (oxidation product, he presumes? dimers?...wonder if the nitro group might promote an autooxidation process perhaps...)

In fact, Toady is going to seal it in a screw-top vial for now, until he gets some more dry IPA to recrystallize it from prior to getting out the LAH.

The stability of the 2,5-dimethoxy-beta-nitrostyrenes is...dubious, at least to some degree, in Toady's opinion.

Anyone happen to know the EtOAc solubility of 2C-D nitrostyrene? He could always whip up a fresh batch of course, but buggered if its going to bee scrapped when it can be cleaned up without too much fuss.

Thanks, Although Tsathoggua was already aware of the possibility of salting out dilute IPA. Anhydrous IPA doesn't appear to be needed for purification of these nitrostyrenes though, the soluability of 2C-D nitrostyrene in dH2O is abysmal, indeed, water was used to wash the nitro prior to recrystallization from MeOH.

He has stuck the nitrostyrene under Ar, in a small glass vial for now.
What he meant, was he needs to get more IPA, full stop. As he has completely run out. Not a problem though.

A sample that was stored from the same batch of 2C-D-nitrostyrene in a small glass vial at room temperature exhibited no change in color,  still bright yellow.