dispatch_queue_t myQueue = dispatch_queue_create("get Token", NULL);
    dispatch_async(myQueue, ^{
        NSURL *myURL = [NSURL URLWithString:@"http://test.myServer.am/api/authentication/Login?username=test&password=test"];

        NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:myURL];
        [request setHTTPMethod:@"GET"];
        [request setValue:@"application/json" forHTTPHeaderField:@"Accept"];
        NSURLResponse *response = nil;
        NSError *myErr;
        NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&myErr];

NSMutableArray *_objects = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&myErr];
        dispatch_async(dispatch_get_main_queue(), ^{

// call more APIs after receiving token

        });