The phrasing of the question is confusing. Is this translated?
to produce 700mg of compound 1 (RMM of 250g/mol) to compound 2 (RMM of 260g/mol)
This doesn't make sense, does it mean:
to
reduce 700 mg of compound 1 to compound 2
or
to produce 700 mg of
compound 2 from compound 1or something else?
I suspect it is the second option, i.e. the reaction is 1
2, the yield is 90% and you need 700 mg of the product 2 - is that correct?
If so:
Hint: How many mmol of 2 are produced? Based on a 90% yield, how many mmol of 1 do you need to produce that?