Shareholder distributions from an S-corp are not compensation from the S-corp. Your compensation from the S-corp available to support an IRA contribution is only what is reported in box 1 of your W-2 from the S-corp and only your compensation supports an IRA contribution.
If you made elective deferrals to a 401(k) plan of the S-corp, the amount in box 1 of your W-2 from the S-corp has already been reduced by the amount of your elective deferrals, so the amount in box 1 of your W-2 from the S-corp remains the amount available to support an IRA contribution.
