1-(3',4'-Dimethylphenyl)-5-methyltetrazole

The Mechanism of Acid Hydrolysis of Guanidines

“…-It has been observed that for solutions of similar water activities (and acidity) that the rates of A2 reactions are faster in hydrochloric and sulfuric acids than in perchloric acid, while the reverse is observed for A1 reactions.11 The data of Table II indicate that the relative rates of hydrolysis of lysidine in the indicated concentrations of perchloric, sulfuric, and hydrochloric acids are 1:2.7:3.1. This order is consistent with that observed for other A2 reactionsfor both amidesllb and esters110 the rates of hydrolysis are twice as fast in 4 M sulfuric acid as in 4 M perchloric acid.…”

“…Because solvation effects on the chemical shifts are expected to be small and TMGH+ has a pKa of 13.6,3 4 the large downfield shift in the methyl singlet of tetramethylguanidine above 84% H2S04 (Table III) suggests protonation of TMGH+ to a diprotonated tetramethylguanidine, TMGíF24•.1 A plot of the chemical (3) V. C. Armstrong, E. W. Farlow, and R. B. Moodie, J. Chem, Soc. B, 1099 (1968).…”

“…of 0.78 and 0.83 at 108.1 and 138.5°, respectively, are consistent with fast preequilibrium protonation of the substrate as indicated in eq 1. For the hydrolysis of lysidine in 4 M sulfuric acid at 90°, ÜhíSOi/d2so« is 0.71.2 Entropies of Activation.-From the rates of hydrolysis of TMG in 4 M sulfuric acid at 108.1 and 138.5°, activation parameters of AS = -25 eu and AH' = 27 kcal/mol may be calculated for the second-order rate constant fci/[H2S04], The entropy of activation is very similar to that observed for the acid hydrolysis of lysidine, -26 eu, and other A2 reactions.2…”

The Chemistry of Formazans and Tetrazolium Salts

“…It seems opportune, therefore, to survey the broader aspects of their chemistry, since this has not previously been done in any detail. obtained by the action of methyl iodide on 5-methyl-l-(3,4-dimethylphenyl)tetrazole (32).…”

Formation of 2-Alkyl-5-phenyltetrazoles from 1-Alkyl-5 phenyltetrazoles

“…After filtration, methylene chloride was evaporated to give 0.2160 g (99%) of colorless liquid identified as 2-ethyl-5-phenyltetrazole (6). There was no detection of the starting ingredient 5 in the product by nmr analysis: bp 123°( 5 mm); nMd 1.5536; nmr (CDClg) 1.68 (t, 3 H), 4.67 (q, 2 ), 7.50 (m, 3 H, meta and para protons), 8.15 ppm (m, 2 H, ortho protons); uv (EtOH) Xmax 239 nm (cmax 15,800).…”