Study of the reactivity of 1,1’-dimethylbistetrazole towards catalytic hydrogenation and chemical reduction

Abstract

Investigating the possibility of a straightforward formation of tetrazoline and/or tetrazolidine structures, the reactivity of a tetrazole derivative towards reducing conditions has been studied. The catalytic hydrogenation of 1,1'-dimethylbistetrazole (DMBT) was carried out using various catalysts (Pd/C, Pt/C, Rh/C, Pd/Pt/C, Lindlar, PtO 2 and Raney Ni) over a wide range of hydrogen pressure (35 to 150 bars) and a temperature range from 20 to 60°C. This exhaustive study enabled to find the optimal conditions for DMBT hydrogenation and to suggest a plausible reaction mechanism. The chemical reduction of DMBT was conducted using several hydrides (BH 3 , NaBH 4 , DIBAL and LiAlH 4 ). The reduction products were identified subsequently to conditions optimizing. The suggested reaction mechanism, featuring a retro-[3+2]-cycloaddition, was validated by both experimental and theoretical approaches.

Copper-Catalyzed Diboron-Mediated cis-Semi-Hydrogenation of Alkynes under Facile Conditions

“…Semi-hydrogenation of alkynes by Pb(OAc) 2 -modified Pd/CaCO 3 , widely known as Lindlar reduction, is the first developed alkyne semi-hydrogenation reaction, and has been widely used in total synthesis [ 25 ]. In addition to Lindlar catalysts, a variety of homogeneous or heterogeneous catalytic hydrogenation systems for semi-hydrogenation based on Pd [ 26 ], Ru [ 27 , 28 ], Rh [ 29 , 30 ], Ir [ 31 ], V [ 32 ], Nb [ 33 ], Co [ 34 ], Cr [ 35 ], Mn [ 36 ], and Fe [ 37 ] have been developed ( Figure 2 a). Nevertheless, the existing Lindlar-type reactions inevitably use high-pressure hydrogen as the hydrogen source, which poses a number of limitations to the reaction, such as potential explosion hazards, cumbersome operations for the use of high-pressure hydrogen, possible over-hydrogenation, and isomerization side reactions.…”