Alkyl and Alkenyl Substituted Azides

The easiest organic azide and smallest member of azidomethanes, CH3N3, was first prepared by O. Dimroth in 1905 by simple methylation of sodium azide with dimethyl sulfate. Methyl azide has been proven to be more explosive than originally reported (same accounts for ethyl azide). The much more hazardous diazidomethane, CH2(N3)2 and triazidomethane, CH(N3)3, are accessible by rather time-consuming slow reactions of dichloro/dibromomethane and tribromomethane with a polymeric ammonium azide reagent. Several reports on the potential risk when working with azides in dichlorometh-ane exist, and are attributed to the potential formation of diazidomethane (please see appropriate references cited in ref. °). 

The synthesis of the ionic triazidocarbenium cation was accomplished as the hexachlo-roantimonate salt, which was later also structurally characterized, being the first and up to date the only X-ray structurally characterized polyazidomethane compound. Further triazidocarbenium salts with energetic counterions such as dinitramide and perchlorate, have been prepared and characterized in detail.  

The trinitroazidomethane was one compound among some selected energetic molecules, which were used in a recent study to predict heats of formation of energetic materials from quantum mechanical calculations.  

The very symmetrical hexakis(azidomethyl)benzene, C6(CH2N3)g, can be prepared easily by bromine/azide exchange, and the explosive properties have been investigated.  

The corresponding aliphatic per-azidomethyl derivative, pentaerythrityl tetraazide, C(CH2N3)4, has been well-known for several years and the crystal structure was recently reinvestigated. The synthesis of the silicon analogue, tetrakis(azidomethyl) silane, Si(CH2N3)4, was reported very recently and can be established in a similar fashion as the carbon analogue by treatment of the chloro derivative with excess sodium azide.  

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