1. N. P. Peet and S. Sunder, U. S. Patent 4,419,357 (Dec. 6, 1983).
2. 3-(1H-Tetrazol-5-yl)-4(3H)-quinazolinone sodium salt (MDL 427): a new antiallergic agent
3. Ortho Esters, Imidic Esters and Amidines. IV. The Mechanism of the Reaction of Aniline with Ethyl Orthoformate1
4. From refluxing ethyl acetate for 4 days, Dowanol PM (glycol ether products) at 100° for 4 days, refluxing toluene (in a Dean Stark apparatus for removal of solvent) for 24 hours, or from slow heating in diphenyl ether at 190°, the sole material found was unreacted amidine 11. Neither 11 nor 7 were recovered from diphenyl ether upon brief heating at 240°. Heating in N/N-dimethylformamide at 140° for 24 hours gave products of amidine bond cleavage. When fusion was attempted by brief immersion of 11 in an oil bath between 200-210°, spectra showed no 7 or 11 present. Proton nmr of spectra of aliquots concentrated from acidic media (catalytic hydrochloric acid, Dowanol PM, 80° catalytic p-toluene-sulfonic acid, refluxing toluene) showed no 11 or 7.