Adicet Bio 10-Q 2012 Q2 Quarterly report

Exhibit 32.1

CERTIFICATION

In connection with the Quarterly Report of Aceto Corporation, a New York corporation (the “Company”), on Form 10-Q for the period ended December 31, 2011 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Albert L. Eilender, Chairman and Chief Executive Officer, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that to my knowledge:

(1) The Report fully complies with the requirements of Section 13(a) and 15(d) of the Securities Exchange Act of 1934; and

(2) The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

/s/ Albert L. Eilender

Chairman and Chief Executive Officer (Principal Executive Officer)

February 9, 2012