Photochemistry of heterocyclic compounds—II

1,3-Dicarbonyl-2-ketimines. Hydrolysis of 1,3-dimethyl-5-(p-tolylimino)barbituric acid

“…ArN-*2c[HA]> ArNH, OH + = (6) buffer concentration expulsion of the amine occurs at a rate comparable to loss of water from the intermediate, so that amine expulsion is partly rate determining. If this step is much more sensitive to buffer catalysis than attack and loss of water,15 increasing the buffer concentration will increase the rate of amine expulsion more than it increases the rate of attack and loss of water, so that at moderate or high buffer concentrations amine expulsion is very fast, the attack step becomes entirely rate determining, and /ccat(eq 1) = k\c-The steadystate rate law for this mechanism is given by eq 7, where Kh…”

“…Anal. (Cl3Hl3N303) C, , N. NMR (CD3CN, Me4Si) 2.36 (s, 3 H, CH3), 3.20 (s, 3 H, NCH3), 3.36 (s, 3 H, NCH3), 6.77 (d, 2 H, aromatic), and 7.25 ppm (d, 2 H, aromatic); mass spectrum m/e 259 (M) and 261 ( + 2).…”

“…The total isolated yield of crude 2 was 112.5 mg (50%). After sublimation and repeated crystallization from carbon tetrachloride 2 was obtained as a white, crystalline solid; mp 113-116 °C; NMR (CDC13, Me4Si) 2.24 (s, 3 H, CH3), 2.95 (s, 3 H, NCH3), 3.05 (s, 3 H, NCH3) 4.23 (s, broad, 1 , NH), 5.07 (s, 1 H, CH), 6.57 (d, 2 H, aromatic), and 7.02 ppm (d, 2 H, aromatic); mass spectrum m/e 233 ( ). A similarly prepared sample of 2, after purification by recrystallization from carbon tetrachloride, sublimation, and subsequent recrystallization from ether, had mp 115-116 °C.…”

Ninhydrin in synthesis of heterocyclic compounds

“…280 The photochemistry of ninhydrin was shown to be dependent on the solvent 281 and the photochemical reaction of ninhydrin derivatives in various solvents was investigated. [282][283] In another study, it was found that indan-1,2,3-trione 2 undergoes photodecarbonylation rather efficiently to produce 216 and 217, which are in a photoequilibrium (Scheme 65). Scheme 69.…”