Specific Isotope Enrichment of Methyl Methacrylate

Specific13C Isotope Enrichment of Isoprene

“…The starting materials used are methyl methacrylate [8] and methyl iodide. The synthesis of isoprene labelled with 13 C at the C-1 and C-2 positions, respectively, has been described before.…”

“…[8] Methyl methacrylate (2) was reduced with LiAlH 4 and subsequently oxidized with MnO 2 . Direct reduction of 2 to give methacrolein (4) is possible with diisobutylaluminium hydride (Dibal-H), but the yield of the two separate reactions together was higher, and the cost of Dibal-H is also higher.…”

“…We have described the preparation of methyl methacrylate 13 C-enriched at any of its four carbon positions and in any combination of positions, in a yield of 30% from acetic acid. [8] The fifth carbon atom in isoprene originates from methyl iodide, which is also available with a 13 C isotope.…”

“…[2Ϫ6] In our group a number of important labelled monomers have already been prepared with 99% 13 C enrichment, namely acrylonitrile, [3] styrene, [3] ethyl acrylate, [7] maleic anhydride, [2,3] and methyl methacrylate. [8] Our purpose of preparing 13 C-labelled isoprene is to use it in anionic block copolymer synthesis. We have prepared block copolymers from isoprene and methyl methacrylate.…”

“…The synthetic scheme is based on the recently developed scheme to synthesize 13 C-labelled methyl methacrylate. [8] The synthesis of isoprene from methyl methacrylate allows the isoprene molecule to be labelled with 13 C at any desired carbon position or in any combination of carbon positions. According to this scheme (4-13 C)isoprene was prepared in a 99% isotopically enriched form.…”