[Sami.allmed]

Hi , i am working as medical system engineer and working on cyclotron project, while reading its chemical process one confusion occur related to mannose triflate which i am unable to solve uptill now, so please help me,

i want to know why mannose triflate is written as

 1,3,4,6–O–Acetyl–2–O–trifluoro-methanesulfonyl–beta–D–mannopyranose (mannose triflate).

and why 1,3,4,5–O–Acetyl–2–O–trifluoro-methanesulfonyl–beta–D–mannopyranose (mannose triflate) is not correct

because acetyl group is on 5th carbon not on sixth and also there is something unsual on sixth carbon i.e oxygen inplace of carbon,

Kindly help me in understanding this formula.

link for mannose triflate formula is here

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3097819/figure/F7/

Thanks

[mjc123]

Look more carefully. The substituent on C5 is not OAc, it is CH₂OAc. Hence the OAc is on C6.

[Sami.allmed]

Thank you so much