HETEROCYCLES
An International Journal for Reviews and Communications in Heterocyclic ChemistryWeb Edition ISSN: 1881-0942
Published online by The Japan Institute of Heterocyclic Chemistry
Regular Issue
Vol. 22, No. 11, 1984
Published online:
■ The Facile Synthesis of Quinoxalinyl-2-oxyphenols
Gozyo Sakata,* Kenzi Makino, and Isao Hashida
*Central Research Institute, Nissan Chemical Industries Ltd., 722-1 Tsuboicho, Funabashi, Chiba 274-8507, Japan
Abstract
Facile synthesis of quinoxalinyl-2-oxyphenols are described. The condensation of 2-chloroquinoxalines with three molar equivalent of dihydroxybenzene in basic medium gave preferentially quinoxalinyl-2-oxyphenols, which involves nucleophilic cleavage of the initially formed bis(quinoxalinyl-2-oxy)benzenes by an excess of dihydroxybenzene.
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■ Reactions of Azomethines and Carbon Suboxide
Leonardo Bonsignore,* Salvatore Cabiddu, Giuseppe Loy, and Mario Secci
*Istituto di Chimica Farmaceutica e Tosshicologica, Università di Catania, Viale A. Doria 6, I-95125 Catania, Italy
Abstract
Some reactions with azomethines and carbon suboxide are re-examined. The results show that working with very diluted and no acid diethyl ether solutions a mixture of 1,5-benzoxazocines and 2-oxo-2H-1-benzopyran-3-carboxamides is obtained.
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■ The Tautomerism of Pyrimidine-2(1H)-one, -Thione and -N-Phenylimine in the 1H- and 13C-NMR
Choji Kashima,* Akira Katoh, Masao Shimizu, and Yoshimori Omote
*Department of Chemistry, University of Tsukuba, 1-1-1 Ten-nodai, Tsukuba-shi, Ibaraki, 305-8571, Japan
Abstract
By the 1H- and 13C-NMR spectral measurement, the structures of the predominant tautomers of 4,6-dimethylpyrimidine-2(1H)-one and -thione were regarded to be the lactam form, while the 2-anilino-4,6-dimethylpyrimidine was the main tautomer. Also, the prototropic interconversion between the tautomers was discussed.
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■ Unambiguous Synthesis of 9-Cyanamino-acridine and 10-Cyano-9-imino-acridane
Joachim G. Schantl* and Wolfgang Türk
*Institut für Organische und Pharmazeutisch Chemie, Universität Innsbruck, Innrain 52, A-6020 Innsbruck , Austria
Abstract
The reaction of cyanogen bromide with 9-amino-acridine 1 affords 10-cyano-9-imino-acridane 2; the isomeric 9-cyanamino-acridine 3 is formed from 9-methoxy-acridine 6 with cyanamide.
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■ Infrared Carbonyl Frequencies of Thiolactones and Lactones
J. Hodge Markgraf*
*Department of Chemistry, Williams College, 47 Lab Campus Drive, Williamstown, MA 01267, U.S.A.
Abstract
Infrared carbonyl frequencies of thiolactones and the carresponding lactones are tabulated according to ring size, substituents, unsaturation, heteroatoms, and solvent effects.