" warning: "B1" redefined" can't upload code to Nano

#define B1  13 //Corresponde a R (LED Vermelho)
#define B2  18 //Corresponde a G (LED verde)
#define B3  19  //Corresponde a B (LED azul)

To save yourself in future, think about including the comment in the literal name.
So, instead of B1, how about

#define LEDVermelho 13

.

In that way, your code is much easier to read.