pKa calculation for L-ascorbic acid?

Hi,

I've just installed the Marvin Sketch 6.1.4 and I am using it to calculate pKa of L-ascorbic acid. I draw the structure (see in ascorbic acid input.mrv), but when I calculated pKa, there is one H missing at the OK next to the ketone group (see in ascorbic acid.mrv). I'm wondering if this is a bug and is there anyway to fix this.

Thanks,

Sophie

Hi,

 

Yes, this is a bug. The major tautomer form generation is missed. 

I fix it asap.

 

Thanks for reporting this bug.

Jozsi 

Thanks, Jozsi.