97945-17-0Relevant academic research and scientific papers
Flash vacuum pyrolysis (fvp) of some hexahydroquinazolin-4(1H)-ones
Peláez, Walter J.,Szakonyi, Zsolt,Fül?p, Ferenc,Yranzo, Gloria I.
, p. 1049 - 1057 (2008/09/17)
Some cis/trans-2-thioquinazolin-4-ones and their 2,4-dione analogs were subjected to flash vacuum pyrolysis. The cis- and trans-thio compounds reacted at lower temperatures than the cis- and trans-dioxo analogs, showing a lower thermal stability. All of these compounds afforded similar reactions: ring opening to the corresponding iso(thio)cyanate, the loss of H{radical dot} and {radical dot}NCS to form three isomeric cyclohexadienes and then aromatization to form the corresponding benzamide. The cis-dioxo compound also underwent a competitive retro Diels-Alder (RDA) reaction to form 3-phenylpyrimidine-2,4(1H,3H-dione(3-phenyluracil)) and butadiene. Kinetic measurements of the ring opening reaction supported a concerted β-elimination as the most probable mechanism.
STEREOCHEMICAL STUDIES, 74. SATURATED HETEROCYCLES, 61. SYNTHESIS AND CONFORMATIONAL ANALYSIS OF 3-SUBSTITUTED-CIS- AND TRANS-4-OXO-4a,5,6,7,8,8a-HEXAHYDROQUINAZOLINE-2(1H)-THIONES AND 4-OXO-4a,5,8,8a-TETRAHYDROQUINAZOLINE-2(1H)-THIONES
Pintye, Janos,Bernath, Gabor,Mod, Laszlo,Sohar, Pal
, p. 71 - 78 (2007/10/02)
cis- and trans-4-Oxo-4a,5,6,7,8,8a-hexahydroquinazoline-2(1H)-thiones (5a,b; 6a,b) and 4-oxo-4a,5,8,8a-tetrahydroquinazoline-2(1H)-thiones (11a,b; 12a,b) were synthesized from cis- and trans-2-amino-1-cyclohexanecarboxylic acid (1,2) and cis- and trans-2-amino-4-cyclohexene-1-carboxylic acid (7,8) by reaction with isothiocyanates (R = Me, Ph).The dependence of the ring closure reaction on the HCl concentration was studied by UV spectroscopy.The conformations of the title compounds were established by 1H and 13C NMR spectroscopy.It was found that compounds 5a,b and 11a,b exist in conformational equilibrium, because of the flexibility of the rings containing the conjugated -CO-NR-CS-NH-system.
