26 CFR 301.6501(n)-2: (n)-2 Certain contributions to section 501(c)(3) organizations.

If a private foundation makes a contribution to a section 501(c)(3) organization as provided in section 4942(g)(3), and a deficiency of tax of such foundation occurs due to the failure of the section 501(c)(3) organization to make the distribution prescribed by section 4942(g)(3), then such deficiency may be assessed within one year after the expiration of the period within which a deficiency may be assessed for the taxable year with respect to which the contribution was made.