Notizen: Vereinfachter Zugang zu 5-Acetyltetrazol / An Expedient Synthesis of 5-Acetyltetrazole

Abstract

5-Tetrazolecarbonitrile, Grignard Reaction, 5-Acetyltetrazole 5-Acetyltetrazole can be obtained in 75% yield by reacting 5-tetrazolecarbonitrile (the latter available by an efficient literature procedure) with an excess o f methylmagnesium iodide.

On the Preparation of 5-(α-DiazoethyI)tetrazoles

“…This route was given preference over a literature m ethod that starts from the carboxylic ester (17: C 0 2Et in place of CN) [8], because in that case * Reprint requests to Prof. Dr. D. Moderhack. the educt (likewise made via ring methylation) was later shown to consist of an inseparable 1:1 mix ture of 1-and 2-methyl isomers [7,9] and, hence, has been used impure [8], For the ketone 10, an expedient synthesis (akin to that shown for 6) has lately been published [10].When the tosylhydrazone 3 was treated in the m anner described for the analogous aldehyde de rivative [4], only traces of the desired diazo com pound 1 (if any) were formed, although for this reaction the more favourable (£')-isomer of 3 was employed [11], In the case of 11, the variant that earlier proved effective with the ring-unsubsti tuted aldehyde congener [1] was tried [i.e., brief heating (< 5 min) with DBN ( 1,5-diazabicyclo-[4.3.0]non-5-ene) in DMSO as solvent], but here too our efforts remained unrewarded. Since under these conditions also both 3 and 7 [the latter avail able in (Z)-form only] turned out to be unsuitable candidates, we converted the above ketones into the hydrazones 4, 8 and 12 [12], When these deriv atives were treated with silver(I) oxide in the pres ence of sodium hydroxide, a smooth reaction oc curred to produce the expected m aterials 1, 5 and 9 in reasonable yield.…”

“…The isomer 6 could easily be made from the nitrile 17 (obtain able as m ajor product by methylation of 16 [7]). This route was given preference over a literature m ethod that starts from the carboxylic ester (17: C 0 2Et in place of CN) [8], because in that case * Reprint requests to Prof. Dr. D. Moderhack. the educt (likewise made via ring methylation) was later shown to consist of an inseparable 1:1 mix ture of 1-and 2-methyl isomers [7,9] and, hence, has been used impure [8], For the ketone 10, an expedient synthesis (akin to that shown for 6) has lately been published [10].…”