Borohydride reduction of the bi-enone (1 ) gave the structurally and mechanistically interesting compounds (4) and (5a-c) resulting from intramolecular carbon-carbon coupling.
Intramolecular photocycloaddition in the bienone(1) has been reported to be inefficient presumably because of the competing facile , b' C-C cleavage> With a view to preparing the biallylic alcohol (2), required for further studies of intramolecular photocycloadditions, we reduced the bienone (1) with sodium borohydride in tetrahydrofuran (THF). The biallylic alcohol (2) (m.p.-f 212-215 O C ; m / e 444) was obtained in only 15% yield. The major products were the hemiacetal (3) (35%;
Oxidation of bis(2-hydroxy-1-naphthyl)methane (4a) with 2,3-dichloro-5,6-dicyano-l,4-benzoquinone (DDQ) has been shown to give the novel compounds, cis-and trans-dispiro(naphtha1ene-1,2'(1'H)-naphtho[2,1-b)pyran-3',1 "-naphthalene}-2(1 H),2"(1 "H)-dione (1 2a) and (13a) together with the quinone methide dimer (6a) and the spiroketone (5a). Compounds (12a) and (13a) were characterised on the basis of their spectral properties and the structures were finally confirmed by an Xray crystal structure analysis of (1 2a). Hydrogenation of compounds (I 2a) and (1 3a) has been shown t o give the dihydroxy compound (14) via CC bond cleavage. An alternative synthesis of the dispironaphthalenones (12a) and (13a) was achieved by oxidation of the dihydroxy compound (14), prepared by an independent method. The generality of the oxidation of bisnaphthols of type (4a) to give novel products of the type (1 2a) and (13a) has been shown by studying the oxidation of the variously substituted bisnaphthols (4b-d,f) with DDQ. A mechanism has been proposed invoking the intermediacy of the quinol ethers (22) and (24).
Rearrangements
Rearrangements O 0140Ecofriendly Solvent-Free Microwave Enhanced Thermal Fries Rearrangement of Anilides and Phenyl Ureas. -Fries rearrangement of anilides and phenylureas under microwave irradiation in the presence of an appropriate Lewis acid adsorbed on an inert solid support provides selectively p-aminoaryl ketones [cf. (II), (IV)] or p-aminoaryl amides (VI), resp., in excellent yields within 3 to 5 minutes. -(EASWARAMURTHY, M.; RAVIKUMAR, R.; LAKSHMANAN, A. J.; RAJU*, G. J.; Indian J. Chem., Sect. B: Org. Chem. Incl. Med. Chem. 44 (2005) 3, 635-637; Dep. Chem., Gov. Arts Coll., Ooty, Tamil Nadu, India; Eng.) -A. Forchert 28-041
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.