1- amino-5-azido-tetrazole

A rather surprising and unusual result was observed in an attempt to prepare 1-amino-5-azido-tetrazole from triaminoguanidinium chloride (Scheme 13.17). ... 

Compound 961 has been converted into 3-amino-6-azido-5(2//)[ 1,2,4]tri-azinone 1041, which was employed in a study of azide-tetrazole equilibrium affording 6-amino-8(5//)tetrazolo[5,1-/][1,2,4]triazinone 1042 (79JHC555) (Scheme 196). 

A very similar rearrangement has been reported for the conversion of 5-amino-l,2,3,4-tetrazole (4) into the 5-(substituted amino)-l,2,3,4-tetra-zole (5) and vice versa (Scheme IV.6) [53JOC779 53JOC1283 54JA88 71JCS(CC)674]. The reaction proceeds via the intermediacy of an azido-... 

Azido-2H-l,2,4-triazin-3-ones (56a) also cyclize to give the tetrazolo[5,l-d]-[l,2,4]triazin-3-ones (56b) (71RRC135, 71RRC311). Nitrosation of 3-amino-6-hydrazino-l,2,4-triazin-5-one (57) affords a compound which exhibits an intense absorption at 2140cm-1, showing that the 6-azido tautomer (58a) was isolated. When this compound was stirred for a few minutes in a polar solvent it quantitatively formed the tetrazole tautomer (58b) (79JHC555). 

Very few syntheses of tetrazoles were reported in 2003. Various a-dialkylated (3-keto esters 219 underwent Schmidt rearrangement with trimethylsilyl azide to give tetrazole 220, which could be elaborated further to azido acid 221, precursors to a-dialkylated a-amino acids <03TL3179>. Di(benzotriazolyl)methanimine 222 reacted with various secondary amines to generate 223, which when treated with sodium azide in the presence of acetic acid yielded N,N-disubstituted 5-aminotetrazoles 224 in moderate to good yields <03JOC4941>. 

Cyclopropan 1-Azido-l-dimethyl-amino- E17b, 1593 (OH - N3) Guanidin 4-Cyan-l-propyl- E4,1299 (OR - NH-C3H7) lH-Tetrazol 1-Butyl- E8d, 679 [HC(OR)3 + R-NH2/NaN3] 4H-1,2,4-Triazol... 

Most unusual is the synthesis of y/c-triazolo[4,5-i/]pyrimidine (262) by heating 6-azido-l,3-dimethyluracil with potassium carbonate in DMF. Whereas intramolecular cyclization of an azide function onto C=N to give tetrazoles is well known, the corresponding formation of triazoles by addition to C=C is extremely rare. Also noteworthy are the 5-diazo-6-amino-uracils (263 R = Me, Et, or Ph), which, although table in boiling acetic acid, cyclize (with loss of nitrogen) in hot DMF to indolo[2,3-d]pyrimidines (264). Far superior are the photodecompositions of (263) which furnish the indolo-pyrimidines in quantitative yield. 

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