Tetrazoles, structure

The tetrazole structure was featured in the stmctures of several medicinal agents whose synthesis was reported in 1996. Notable among these reports was the preparation of tetrazole-... 

No. Application Tetrazole structure tetrazole containing molecular type Ref... 

Compound (159) has an IR band at 1070 cm-1, in neutral solution or the solid state, consistent with the tetrazole structure. In trifluoroacetic acid this band is replaced by a typical azide absorption at 2140 cm-1. Only in this solvent will photolysis give a good yield (91%) of the pyrimidinoindole (160) (72JOC3216). 

Measured dipole moments for a series of substituted tetrazoles gave interesting comparisons (56JA4197). The moments for 1-ethyltetrazole (5.46 D) and 2-ethyl tetrazole (2.65 D) were at either side of the mesoionic compound (7) (4.02 D) and the dipole moments could not be used to identify mesoionic structures. The dipole moments for the 1,5-disubstituted tetrazole structure were consistently high, >5.3 D, while those of the 2,5-disubstituted structure were low, <2.65 D theoretical calculations support this (61T237). Recently, dipole moment measurements were made on 5-(p-tolyl)tetrazole in dioxane (fio 4.99), its 1-methyl isomer 6.03) and its 2-methyl isomer (jUd 2.41) (80JHC1374). These results, when applied to the annular tautomerism of 5-( p-tolyl)tetrazole, suggested 60 10% of the 1-NH form in this medium. 

Pyrazolo[5,l-d][l,2,3,5]tetrazin-4-ones synthesis, 3, 535 Pyrazolo[ 1,5-d]tetrazole structure, S, 263... 

A few papers with fused tetrazole structures were published. 

---