La diferencia entre so y such ya la hemos explicado aquí. Al usar estas partículas de comparación con un infinitivo se debe añadir el infinitivo con to.

Presentación de forma esquemática
so + Adjektiv + as + to + Infinitiv
such + Substantiv + as + to + Infinitiv
Ejemplos
He is not so stupid as to eat this food.
We are not so tired as to stay home all evening.
She is not such a fool as to give you money.
They are such thickheads as to understand the good idea.