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Chemistry Forums for Students => Organic Chemistry Forum => Organic Chemistry Forum for Graduate Students and Professionals => Topic started by: Nescafe on June 14, 2013, 05:13:53 PM

Title: Glucose Coupling and confusing mass spec
Post by: Nescafe on June 14, 2013, 05:13:53 PM

Hello,

I have been trying to get this gycosyl ester product (couple on a tert-O-benzyl protected alpha-D-glucose) to a free benzoic acid functionality on a body of my molecule which is quite a simple structure. So after a couple of attempts managed to get it to work by activating the acid using isobutyl chloroformate, Nmethylmorpholine and introducing the protected glucose (with tertbutoxide) in THF. Nice one spot, based on NMR pretty promising as well.

Just did a mass spec ESI (+ ve) and I see a mass of 1103 which is 29 short of what I expect (1132). Anyone here experienced enough with glucose to know whether it undergoes a particular rearrangement in ESI that could result in a loss of 28-30 m/z units? (CH2=O?)

Cheers,

Nescafe.

Title: Re: Glucose Coupling and confusing mass spec
Post by: MOTOBALL on August 20, 2013, 04:11:20 PM

If this is still an issue, can you post the mass spectrum in the range of about m/z 900-1200.