An organization described in Section 23701d which is subject to the provisions of this article, except those specified in Sections 23736, shall not be exempt from taxation under Article 1 of this chapter if it has engaged in a prohibited transaction after January 1, 1951; and an organization described in Section 23701n which is subject to the provisions of this article shall not be exempt from taxation under Article 1 of this chapter if it has engaged in a prohibited transaction after December 31, 1960.