*  Patent US6930197 - Antihistaminic piperidine derivatives and intermediates for the preparation ... - Google Patents
Synthesis of 1-Substituted 4-(5-Tetrazolyl)thio-1-butanones and Related Compounds, Chem. Pharm. Bull (1989, pp. 958-961, vol. ...
http://www.google.com/patents/US6930197