- Palladium-Catalyzed Cyclocarbonylation of o-Iodophenols and 2-Hydroxy-3-iodopyridine with Heterocumulenes: Regioselective Synthesis of Benzo[e]-1,3-oxazin-4-one and Pyrido[3,2-e]-1,3-oxazin-4-one Derivatives
-
Benzo[e]-1,3-oxazin-2-imine-4-ones (3) were synthesized by cyclocarbonylation of o-iodophenols with carbodiimides in the presence of a catalytic amount of a palladium catalyst and 1,4-bis-(diphenylphosphino)butane under CO pressure. Product yields are dep
- Larksarp, Chitchamai,Alper, Howard
-
p. 9194 - 9200
(2007/10/03)
-
- Multivariate regression with substituent shift increments. IV. 2-(4-X-phenyl)-1,3-dihydro-2H-isoindole-1,3-diones and 3-(4-X-phenyl)-3,4-dihydro-2H-1,3-benzoxazine-2,4-diones
-
Two series of para disubstituted benzenes were studied: 2-(4-X-phenyl)-1,3-dihydro-2H-isoindole-1,3-diones (1) and 3-(4-X-phenyl)-3,4-dihydro-2H-1,3-benzoxazine-2,4-diones (2). Their 1H and 13C chemical shifts were correlated with substituent shift increments (SSI) aj and zj, respectively. For 13C chemical shifts, all four zj values, zj, zo, zm, and zp, were used to check the assignment and to find out possible variables for improvement of regression equations. Significant deviations from plain additivity were observed in the case of δH3 and δC3 chemical shifts. This can be explained by changes in diamagnetic anisotropy contribution induced by different twist of 4-substituent from the benzene plane caused by variable substituent in position 1.
- Holik, Miroslav,Friedl, Zdenek,Waisser, Karel,Gregor, Jiri
-
p. 1709 - 1726
(2007/10/03)
-
- NEW GROUPS OF POTENTIAL ANTITUBERCULOTICS: 3-ARYL-2H,4H-BENZOXAZINE-2,4-DIONES. COMPARISON OF THE TOPLISS APPROACH WITH REGRESSION ANALYSIS
-
3-Phenyl-2H,4H-benzoxazine-2,4-dione (I) and its derivatives II - XI, substituted on the phenyl ring, can be regarded as a new group of potential antituberculotics.Their activity increases with increasing electron-accepting properties of the substituents.Introduction of bromine into the position 6 also positively influences the activity.The compounds are active in vitro against Mycobacterium tuberculosis and M. kansasii.The activity of some of them (VIII, IX) exceeds that of commercial tuberculostatics used as standards.
- Waisser, Karel,Kubicova, Lenka,Klimesova, Vera,Odlerova, Zelmira
-
p. 2977 - 2982
(2007/10/02)
-
- Reactions of 2-Hydroxybenzonitrile with Isocyanates
-
Triethylamine catalyzes the reaction of 2-hydroxybenzonitrile (1) with arylisocyanates to form the corresponding carbamates 2a-c, as well as the cyclization of the latter compounds to either 4--3-aryl-2H-1,3-benzoxazin-2-ones 4a-c, or 4-arylamino-2H-1,3-benzoxazin-2-ones 7a-c, depending on the reaction temperature.Under analogous conditions, the carbamates obtained from 1 and 2-chloroethyl isocyanate, 3-chloropropyl isocyanate and ethyl isocyanatoacetate undergo a double cyclization yielding imidazo- and pyrimidobenzoxazinones 13a, b, 17.Upon heating in phenyl ether, compounds 7a-c, rearrange to 2-(2-hydroxyphenyl)-4(3H)-quinazolinones 10a-c.
- Petridou-Fischer, J.,Papadopoulos, E. P.
-
p. 1159 - 1167
(2007/10/02)
-