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 +
adjetivo + as + to + infinitivo
such
+ sustantivo + as + to + infinitivo
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.
