I have a six-tone scale with the notes A#,B,C,D,D#,G. As far as I'm aware this is not contained in any other well known scale. What should I call it?
These notes are (enharmonically) a subset of the 8-note major Bebop scale with root Eb:
Eb (F) G (Ab) Bb B C D
where the notes in parentheses are the ones that you leave out to get your six-note scale.
Here's a few guidelines for naming scales:
Well, it's a gapped scale (less than seven notes in the octave). You might call it a hextonic scale.
Most scales are named after the gap between the first and third elements. A# to a C is a diminished third.
Scales are always spelled sequentially, so there shouldn't be 2 D's, the second one is an Eb.
So you could call it as Diminished Hextonic.
Another approach is to find a chord which fits these notes and just name it for the chord.There's a Cminor chord in there (C, Eb, G), so look at how that's extended. with a major 7th (B), so it's now a Cminor(maj7). Then the A#, which could also be spelled as a Bb, is a minor seventh. So perhaps Cm7(+M7).
However, none of these are a standard, well-known scale, so I'd declare what notes it has explicitly. Or if you're writing standard score, just write in all the accidentals as they're used.