5-Amino-l//-tetrazole

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-... 

Similarly, 5-picrylamino-l,2,3,4-tetrazole (PAT) (116) " " and 5,5 -styphnylamino-1,2,3,4-tetrazole (SAT) (117) " have been synthesized by condensing picryl chloride and styphnyl chloride with 5-amino-l,2,3,4-tetrazole in methanol respectively. A comparison of thermal and explosive properties of newly synthesized PAT (calculated VOD 8126 m/s) and SAT (calculated VOD 8602 m/s) reveals that PAT is more thermally stable than SAT but more sensitive to impact and friction. " ... 

The thermal isomerization of substituted 5-amino-l,2,3,4-tetrazoles in ethylene glycol, viz. 

Agrawal and co-workers reported the synthesis of two tetrazole-based explosives, namely, 5-picrylamino-l,2,3,4-tetrazole " (PAT) (149) and 5,5 -styphnylamino-l,2,3,4-tetrazole (SAT) (150) from the reaction of 5-amino-1,2,3,4-tetrazole (148) with picryl chloride and styphnyl chloride respectively. These explosives have been studied for their thermal and explosive properties. The thermal stability of SAT (exotherm peak at 123 °C) is lower than PAT (exotherm peak at 185 °C), which is possibly attributed to the decreased electron-withdrawing power of the picryl group by being attached to two tetrazole units. PAT and SAT have calculated VODs of 8126 m/s and 8602 m/s respectively. ... 

The procedure is essentially similar to that described for the preparation of 5-amino-l,2,3,4-thiatriazole. Freund and Hempel6,7 have reported observing that the initial diazotization products of 4-aryl-substituted thiosemicarba-zides lead to the formation of tetrazoles, while the corresponding 4-alkyl-substituted thiosemicarbazides were considered by Freund and Schwarz8 to be thiatriazoles. However, Oliveri-Mandala,9 on the basis of his study of the reaction of alkyl and aryl isothiocyanates with hydrazoic acid, concluded that the initial diazotization product of either 4-aryl or 4-alkyl thiosemicarbazides were open-chain thiocarbamyl azides, RNHC( S)N3. Lieber, Pillai, and Hites10 have recently clarified this situation and have shown... 

Cefoperazone Cefoperazone, (6/ ,7/ )-7-[(/ )-2-(4-ethyl-2,3-dioxo-l-piperazincarboxam-ido)-2-(p-hydroxyphenyl)acetamido]-3-[[(l-methyl-l//-tetrazol-5-yl)thio]methyl]-8-oxo-5-thia-l-azabicyclo[4.2.0]oct-2-en-2-carboxylic acid (32.1.2.84), is synthesized by acylating 7-amino-3-(l-methyl-l,2,3,4-tetrazol-5-yl)-thiomethyl-3-cefem-4-carboxylic acid (32.1.2.24) with a mixed anhydride synthesized from ethyl chloroformate and a-(4-ethylpiperazin-2,... 

Bamberger, Padova, and Ormerod reported in 1926 an interesting but incomplete study of several unusual products obtained from 5-amino-2,3-diaryl-l,2,3,4-tetrazolium salts (400). Recently this topic has been the subject of a detailed study by I. S. Smith, and the existence of several derivatives of meso-ionic l,2,3,4-tetrazol-5-imines (399) has now been firmly established. Comparison of Smith s recent results with the earlier results of Bamberger et alP is instructive. 

The first representative of this class of meso-ionic heterocycles was the 1,3-dimethyl derivative (293, R1 = R2 = Me, R3 = H) obtained by methylation of 5-amino-2-methyltetrazole with methyl benzene-sulfonate.208 Meso-ionic l,2,3,4-tetrazol-5-acylimides (293, R1 = R2 = Me, R3 = Me.CO, p-Me.C6H4.S02, p-Cl.C5H4.SO2) have been prepared by methylation of the corresponding 1-methyltetrazole using dimethyl sulfate.209,210 The sequence 293, R1 = R2 = Me, R3 = Me.CO - R3 = H - R3 = p-Me.C6H4S02, was achieved by acid hydrolysis followed by tosylation. The substances (293, R1 = R2 =Me, R3 = H) prepared by the two routes are identical.208,210... 

Amino-l-p-ethoxyphenyla-viC tetra ole or l-p-Ethox ypbenyl-5-amino- 1H- 1,2,3,4-tetrazole, (p-C2 H, O CgH4)... 

Fig. 2.4 Structures of agonists and antagonists of kainate receptors. 5-1 Will, 5-iodowillardiine (a) SYM 2081, (25,4R)-4-methylglutamate (b) 2S,AR isomer of 4-cinnamylglutamic acid (c) AMOA, (RS)-2-amino-3-(3-carboxymethoxy)-5-methylisoxazol-4-yl]propionic acid (d) AMNH, (RS)-2-amino-3-[2-(3-hydroxy-5-methylisoxazol-4-yl)-methyl-5-methyl-3-oxoisoxazo-lin-4-yl)]propionic acid (e) and LY 294486, (3SR,4aRS,6SR,8aRS)-6-[(lH-tetrazol-5-yl)methoxymethyl]-l,2,3,4,4a,5,6,7,8,8a-decahydroisoquinoline-3-carboxylic acid (f)...

Amination at an azole ring nitrogen is known for N-unsubstituted azoles. Thus, 1,2,3-triazole and 4,5-diphenyl-l,2,3-triazole with hydroxylamine-O-sulfonic acid give 1-amino 145 and 2-amino 146 derivatives in a ratio of 4 1 and 1 3, respectively. 3-Amino-5-/isy/-butylpyrazole affords 147 and indazole and tetrazole give comparable amounts of the 1- and 2-amino derivatives, and ethyl benzothiazol-2-ylcarboxylate reacts at room temperature <2001JOC8528>. Pyrazole is easily N-nitrated with nitrogen dioxide in the presence of ozone <1996JCR(S)388>. 

Amino-l-ethyl-1/f-tetrazole, in A-70202 5-Amino-2-ethyl-2/f-tetrazole, in A-70202 1,4-Dihydro-5-imino-3,4-dimethyltctrazole, in A-70202... 

Aminocephalosporanic acid 22 condenses with 1-methyl-1,2,3,4-tetrazol-5-thiol in the presence of chloro- or fluorosulfonic acid in acetonitrile at RT to give 7-amino-3-(l-methyltetrazol-5-ylthiomethyl)-3-cephem-4-carboxylic acid (23, 90% yield) (Equation 1) ... 

It should be emphasized that the correct description of the peculiar effect brought about by the presence of two or more sp -nitrogen centers within a molecule can be reproduced reliably only by high level ah initio calculations accounting for electron correlation. This conclusion is well justified by the examples of benzotriazole, 3-amino-l,2,4-triazole, and tetrazole, as described in Sections II,B,3 II,B,4 and II,B,5, respectively. 

---