Activation tetrazoles

In general 1,5-dialkyltetrazoles, in which the A(l)-substituent has four to six carbons, show activity on the central nervous system. When the 1- and 5-positions are bridged by a methylene chain, the activity is maximized. Pentamethylene tetrazole (244), which is probably the most important biologically active tetrazole, is a standard drug in this area... 

Biologically Active Tetrazoles (—CN4H versus—C02H) 355... 

The reactive amidite and activator (tetrazole) are generally dissolved in dry acetonitrile. The quality of anhydrous acetonitrile used in dissolving amidite is as important as the equivalent of reagents delivered and amount required for fluidization to achieve good-quality synthesis. Any contamination with water can reduce the reactivity of an amidite, hence lowering the coupling efficiency and resulting in a poor-quality... 

Furthermore, the decrease in effectiveness of an amidite in solution owing to the presence of moisture also depends on time. A 50 omol solution of an amidite with 100 ppm water content over the lapse of time may not even be a 35.0 pmol solution. Therefore, it is recommended that reagents and solutions be freshly prepared in anhydrous solvent. Especially, amidite solutions should be prepared from good-quality and anhydrous acetonitrile, which many vendors supply. The presence of moisture in an activator tetrazole solution also effects the quality of synthesis. The effect of moisture can be eliminated by placing a trap-bag in this solution. 

Alkyl groups and halogen atoms in tetrazoles are not highly activated unless the ring is quaternized. 

Chromone, 3-(tetrazol-5-yl)-antiallergic activity, 5, 836 degradation, 5, 815 Chromone, 3,5,7-trimethoxy-2-methyl-photolysis, 3, 695... 

Tetrazole, 5-phenoxy-l -phenyl-mass spectra, 5, 801 photolysis, 5, 811 Tetrazole, 1-phenyl-deuterium-hydrogen exchange, 5, 806 mercuration, 5, 59 NMR, 5, 798 tautomerism, 5, 804 UV spectra, 5, 798 Tetrazole, 2-phenyl-NMR, 5, 798 tautomerism, 5, 804 UV spectra, 5, 798 Tetrazole, 5-phenyl-alkylation, 5, 818 anti-inflammatory activity, 5, 835 blowing agent, 1, 410 reactions... 

Tetrazole, l-(p-substituted phenyl)-antimicrobial activity, 5, 835 Tetrazole, 5-thio-rearrangements, 5, 823 Tetrazole, 2-thioacyl-reactions, 5, 109 Tetrazole, 5-(o-tolyl)-tautomerism, 5, 804 Tetrazole, 5-(p-tolyl)-dipole moments, 5, 795 tautomerism, 5, 804 Tetrazole, 5-(trimethylsilylamino)-synthesis, 5, 832 Tefrazolecarbaldehydes reactions, 5, 820 Tetrazole-5-carbaldehydes reactions, 5, 820 Tetrazolecarbonitriles reactions, 5, 820 Tetrazole carbonyl compounds reactions, 5, 820 Tetrazolecarboxylic acid, 5-aryl-acidity, 5, 816... 

Tetrazole synthesis (torn azides by dipolar cycloadd ition with activaled n ltnies or intramolecularly with nitriles in the presence of acids. 

The free energy of activation at the QCISD(T)/6-31 H-- -G(d,p) level amounts to 21.1 kcal/mol. According to the authors, the large electron density redistribution arising upon cyclization makes it necessary to use extended basis sets and high-order electron correlation methods to describe the gas-phase thermodynamics, which indicates clearly the gas-phase preference of the azido species. However, the equilibrium is shifted toward the tetrazole as the polarity of a solvent is increased. For instance, SCRF calculations (e = 78.4) yield a relative free energy of solvation with respect to the cw-azido isomer of —2.4 kcal/mol for the tmns-zziAo compound and of —6.8 kcal/mol for the tetrazole isomer. At a much lower level, the... 

Conversion of m-bromobenzonitrile to the tetrazole and addition of the elements of acrylic acid gives 7S, starting material for the patented synthesis of the antiinflammatory agent, bropera-mole (76). The synthesis concludes by activation with thionyl chloride and a Schotten-Baumann condensation with piperidine. 

Tachykinins, 43 (2005) 50 Tetrahydroisoquinolines, B-adrenomimetic activity, 18 (1981) 45 Tetrazoles, 17 (1980) 151 Thalidomide as anti-inflammatory agent,... 

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