Benzo[b]thioxanthenes, heterocyclic compounds related to tetracenes and tetracyclines can be obtained by the reaction of 2H-benzo[b]thiete (1) and 1,4-naphthoquinones (3a-g). The primary cycloadducts 4a-g undergo an autoxidation process leading to the quinones 6a-g. The dihydroxy compound 4e shows an additional isomerization by a tetra-fold H transfer (4e --> 5e'). Another preparative route to benzo[b]thioxanthenes makes use of the cycloadditon reaction of 1 and 1,4-epoxynaphthalenes (7a-d). The primary adducts can be transformed to the title compounds by catalytic dehydration processes (8a-d --> 9a-d). An alternate regioselective opening of the oxygen bridge can be performed by the action of trimethyliodosilane (8a --> 10a). Methylation of 9a furnishes the sulfonium salt 14a which rearranges in a strongly alkaline medium to 16a; in the presence of oxygen ketone 17a is generated.
Synthesis of Alkyl- and Alkyloxy-Substituted 2,3-Naphthalocyanines
摘要:
Four novel differently substituted 2,3-dicyanonaphthalenes (6-(hexyloxy)-2,3-dicyanonaphthalene (5), 5-(hexyloxy)-2,3-dicyanonaphthalene (11), 6,7-bis(hexyloxy)-2,3-dicyanonaphthalene (17), and 5,8-diheptyl-2,3-dicyanonaphthalene (22)) and the respective peripherally substituted (bis(tert-butylisocyano)-2,3-naphthalocyaninato)iron(II) compounds 23-26 were synthesized and characterized.
Synthesis and Stereochemistry of Diepoxynaphthacenes and Tetraepoxyheptacenes
作者:Herbert Meier、Bernd Rose
DOI:10.1002/jlac.199719970407
日期:1997.4
Cycloadditionreactions of 1,4-dihydro-1,4-epoxynaphthalenes (2) and benzo[c]furans (4), generated in situ from the tetracyclone adducts of 2, yield the diepoxynaphthacenes 5 (Schemes 1, 2). Out of 4 possible stereoisomers an exo-exo and an exo-endo geometry (A and C in Scheme 3) can be realized. The ratio A:C varies from pure A to pure C depending on the substituents of 2 and 4. Stereoisomeric heptacenes
1,4-二氢-1,4-环氧萘(2)和苯并[ c ]呋喃(4)的环加成反应是由四环酮加合物2原位生成的,生成双环氧萘5(方案1、2)。在4种可能的立体异构体中,可以实现exo-exo和exo-endo几何形状(方案3中的A和C)。比值A:C从纯A到纯C取决于取代基而变化2和4。立体异构庚烯7可以通过相同类型的两倍环加成获得(方案4)。反应性炔烃(例如环辛炔或炔二羧酸酯)只有一个π键能够加成4(方案5、6)。
Angular benzobisthietes
作者:Herbert Meier、Norbert Rumpf
DOI:10.1016/s0040-4039(98)02265-5
日期:1998.12
The angular benzobisthietes 3 and 5 could be prepared by synthetic sequences in which the final step was in both cases a twofold dehydration of the corresponding bis(hydroxymethyl)dimercaptobenzenes 10 and 14, respectively. Flash vacuum pyrolysis conditions were used for the generation and isolation of 3 and 5 which are highly reactive bisdiene systems. Cycloaddition reactions with the dienophiles 15 and 18a,b led to the adducts 16, 17, and 19a,b. (C) 1998 Elsevier Science Ltd. All rights reserved.