Alkyl-Bridged Bis-5-azidotetrazoles: A Safe Way of Preparation

The general, high-yielding synthesis of extremely dangerous alkylated bis-5-azidotetrazoles is presented. The preparation using 5-bromotetrazoles for the generation of tetrazolyl hydrazines, which are then converted into the corresponding bis-5-azidotetrazoles, presents a safe, large-scale preparation of alkylated bis-5-azidotetrazoles. In this work, 1,2-bis(5-azido-1H-tetrazol-1-yl)ethane, 1,2-bis(5-azido-1H-tetrazol-1-yl)-1-methylethane, and 1,4-bis(5-azido-1H-tetrazol-1-yl)butane were synthesized and characterized by H-1, C-13, and N-15 NMR spectroscopy, vibrational spectroscopy (IR), and mass spectrometry. The crystal structure of 1,2-bis(5-azido-1H-tetrazol-1-yl)ethane was determined by single-crystal X-ray diffraction. In addition, the thermal behavior of the bis-5-azidotetrazoles was investigated by differential scanning calorimetry and their sensitivity towards friction and impact were determined. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)