How to convert LaTeX to expression without interpreting variables as products?

I need to convert some LaTeX code to mathematica expressions. So far I have used

ToExpression["ab", TeXForm]

yielding ab, i.e. mathematica variable with the name "ab". This is what I want. However, the LaTeX code I would like to convert may be e.g. "2 ab".Using

ToExpression["2 ab", TeXForm]

then returns 2 a b, i.e. a product of a and b. How can I avoid this?