caa a22 4500 467991634 CHVBK 20180323112546.0 cr unu---uuuuu 170328e19900701xx s 000 0 eng 10.1007/BF00509699 doi (NATIONALLICENCE)springer-10.1007/BF00509699 Oxidative opening of the 2,5-dihydroxy-3,4,6,7-tetrachlorocoumaran ring [Elektronische Daten] [G. Karlivan, V. Zin'kovskaya, R. Valter, R. Kampare] A method has been developed for the synthesis of (3,5,6-trichloro-1,4-benzoquinone-2-yl)chloroacetaldehyde by the oxidative ring opening of 2,5-dihydroxy-3,4,6,7-tetrachlorocoumaran with nitrogen oxides. The ion-radical salt of (3,5,6-trichloro-1,4-benzoquinone-2-yl)chloroacetaldehyde with N,N,N′,N′-tetramethyl-p-phenylenediamine (1∶1) has been synthesized. The reaction of 2,5-dihydroxy-3,4,6,7-tetrachlorocoumaran-3-yl) with pyridine gave N-(2,5-dihydroxy-4,6,7-trichlorocoumaran-3-yl)pyridine chloride, which is also formed from the opening of the coumaran ring. Plenum Publishing Corporation, 1991 Karlivan G. Riga Technical University, 226355, Riga aut Zin'kovskaya V. Riga Technical University, 226355, Riga aut Valter R. Riga Technical University, 226355, Riga aut Kampare R. Riga Technical University, 226355, Riga aut Chemistry of Heterocyclic Compounds Kluwer Academic Publishers-Plenum Publishers 26/7(1990-07-01), 743-745 0009-3122 26:7<743 1990 26 10593 https://doi.org/10.1007/BF00509699 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00509699 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Karlivan G. Riga Technical University, 226355, Riga aut NATIONALLICENCE 700 1- Zin'kovskaya V. Riga Technical University, 226355, Riga aut NATIONALLICENCE 700 1- Valter R. Riga Technical University, 226355, Riga aut NATIONALLICENCE 700 1- Kampare R. Riga Technical University, 226355, Riga aut NATIONALLICENCE 773 0- Chemistry of Heterocyclic Compounds Kluwer Academic Publishers-Plenum Publishers 26/7(1990-07-01), 743-745 0009-3122 26:7<743 1990 26 10593 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer