How do I overwrite a string with an accent for another without?

I wanted to replace the accented characters with other ones without and generate a new string, but there seems to be something wrong in the comparison I'm trying to do in the extractAcento function. I looked at the ASCII table, but I still did not get the error. Maybe it's the use of the pointer, I do not know.

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>

/* run this program using the console pauser or add your own getch, system("pause") or input loop */

#define num_moveis 4
#define max_caracteres 256
char retiraAcento(char * nome, int tam);
int verificaNome(char * nome, int tam);
char leValidaNome(char * prodAux);
void menu(char moveis[][256]);
int main(int argc, char *argv[]) {
    char moveisDisponiveis[num_moveis][max_caracteres] = {{"sofa"}, {"mesa"}, {"estante"}, {"escrivaninha"}};
    char prodAux[max_caracteres];
    menu(moveisDisponiveis);
    leValidaNome(prodAux);





    return 0;
}
void menu(char moveis[][256]){
    int i=0;
    printf("Relacao dos moveis disponiveis\n\n");
    for(i=0; i < num_moveis; i++){
        printf("%s\n", moveis[i]);
    }
}
char leValidaNome(char * prodAux){
    int tam = 0, flag = 1;
    do{
        //system("cls");
        printf("\nInforme o produto desejado:");
        scanf(" %[^\n]s", prodAux);
        *prodAux = tolower(*prodAux);
        tam = strlen(prodAux);
        retiraAcento(prodAux, tam);
        //printf("%s", prodAux);
        flag = verificaNome(prodAux, tam);
        system("cls");
        if(flag == 0){
            printf("\nNome vazio ou com numeros!\n");
        }



    }while(!flag);

    return *prodAux;
}
int verificaNome(char * nome, int tam){

    int i=0, flag = 1;
    if(tam == 0){
        flag = 0;
    }else{
        for(i; i < tam; i++){
            if(isdigit(nome[i])){
                flag = 0;
            }else{
                flag = 1;
            }
        }
    }
    //printf("%d", flag);
    return flag;
}
char retiraAcento(char * nome, int tam){
//á = 225, à =224 , é=233, è=232, í=237, ì=236, ó=243, ò = 242, ú = 250, ù = 249
//falta acrescentar mais alguns caracteres  
    unsigned char i;

    for(i=0; i < tam; i++){
        if(nome[i] == 225 || nome[i] ==  224){
            nome[i] = 97;
        }else if(nome[i] == 233 || nome[i] == 232){
            nome[i] = 101;
        }else if(nome[i] == 237 || nome[i] == 236){
            nome[i] = 105;
        }else if(nome[i] == 243 || nome[i] == 242){
            nome[i] = 111;
        }else if(nome[i] == 250 || nome[i] == 249){
            nome[i] = 117;
        }
    }
    //printf("%s", nome);
    return *nome;
}