ISSN:
0947-3440
Schlagwort(e):
Tetrahydropyranyl-ethers
;
ortho-Lithiation
;
ortho-Alkylation
;
1,4-Benzoquinones, alkyl-methoxy
;
1,4-Benzoquinones, alkyl-hydroxy-methoxy-
;
Chemistry
;
Organic Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
Synthesis of Natural Compounds with Alkyl-methoxy-1,4-benzoquinone StructureThe 1,4-benzoquinones 1-7 occurring in various plants and having interesting biological properties have been synthesized from the tetrahydropyranyl ethers 17 and 21. Reaction with n-butyllithium gave selectively the ortho-lithiated compounds. These could be alkylated with the haloalkenes 13-16 and haloalkanes to give the substituted phenols 18-20 and 22-25 in high yield after methanolysis. Alkylations of the methoxyisopropylether 8 of 10-undecyn-1-ol with bromobutane and bromohexane gave 9 and 10. These alkynols could be selectively hydrogenated with Lindlar-Palladium catalyst to give the (Z)-alkenols 11 and 12 which could be converted into the bromoalkenes 13, 14 and the iodoalkenes 15, 16. Oxidation of the phenols 18-20 and 22-25 with molecular oxygen in the presence of salcomine as catalyst produced the substituted 1,4-benzoquinones 1-3 and 26-29 in high yield. Selective hydrolysis with perchloric acid converted 26-29 into the natural products 4-7.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/jlac.199519950118
Permalink
