Kindly suggest me where I'm I going wrong, It works perfectly fine in cURL but when i try doing in in salesforce I'm facing all these Issues

This is My cURL

```
curl -H "Authorization:Bearer 7512d7f8-2706-4dcd-a288-af482fb728ca" -H "Content-Type: application/json" -d '{"filter" :{}}' https://sandbox-api.flipkart.net/sellers/orders/search

```

Equivalent Http method 

**My Access Token : 7512d7f8-2706-4dcd-a288-af482fb728ca**

```
public static void new_version(){

        string tok = 'https://sandbox-api.flipkart.net/sellers/orders/search';
        HttpRequest req = new HttpRequest();
        req.setMethod('POST');
        req.setTimeout(60*1000);        
        req.setEndpoint(tok);

        Blob headerValue = Blob.valueOf('7512d7f8-2706-4dcd-a288-af482fb728ca');
        String authorizationHeader = 'BASIC ' + EncodingUtil.base64Encode(headerValue);
        req.setHeader('Authorization' + 'Bearer', authorizationHeader);
        req.setHeader('Content-Type', 'application/json');
        system.debug('@@@@@@@'+req);

        Http h = new Http();
        String resp;
        HttpResponse res = h.send(req);
        resp = res.getBody();        
        system.debug('@@@@@@@@@@'+res);

    }

```

Error Which I'm facing 

```
System.HttpResponse[Status=Unauthorized, StatusCode=401]

```