- Directed metalation?£?cross-coupling strategies. Total syntheses of the alleged and the revised phenanthrene natural product gymnopusin
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The total synthesis of gymnopusin (2) is described. The originally assigned structure for gymnopusin 1a was found to be incorrect by total synthesis using the Directed ortho-Metalation (DoM)?£?Cross- Coupling?£?Directed remote Metalation (DreM) sequence, a demonstrable key strategy for the regioselective construction of the 9-phenanthrol core. The revised structure of gymnopusin (2) was confirmed by synthesis by adopting the same strategy but involving a key remote anionic Fries-rearrangement step. Both routes highlight methodologies and concepts which may be of value in the regiocontrolled synthesis of phenanthrenoids specifically and in complex polycyclic aromatics in general. Copyright
- Wang, Xin,Fu, Jian-Min,Snieckus, Victor
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p. 2680 - 2694
(2013/03/13)
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- Palladium-catalyzed cross-coupling of N-benzenesulfonyl-3,4-dibromopyrrole and its application to the total syntheses of lamellarins O, P, Q, and R
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Palladium-catalyzed Suzuki-Miyaura coupling of N-benzenesulfonyl-3,4-dibromopyrrole with a variety of arylboronic acids gave the corresponding 3,4-diarylpyrroles in high yields. The 3,4-differentially arylated pyrroles could also be prepared by stepwise cross-coupling approach. The total syntheses of lamellarins O, P, Q, and R have been achieved by using the cross-coupling and the directed lithiation as key reactions.
- Fukuda, Tsutomu,Sudo, Ei-ichi,Shimokawa, Kozue,Iwao, Masatomo
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p. 328 - 338
(2008/04/01)
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- Heterocyclic compounds
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The invention concerns pharmaceutically useful compounds of the formula I, in which A1, A2, A3, A4, B1, m, Ar, W, X, Y, Z and R1 have any of the meanings defined herein, and their pharmaceutically acceptable salts, and pharmaceutical compositions containing them. The novel compounds possess endothelin receptor antagonist activity and are useful, for example, in the treatment of diseases or medical conditions in which elevated or abnormal levels of endothelin play a significant causative role. The invention further concerns processes for the manufacture of the novel compounds and the use of the compounds in medical treatment.
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- PHENYL SULFONAMIDE ENDOTHELIN ANTAGONISTS
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Compounds of the formula STR1 inhibit the activity of endothelin. The symbols are defined as follows: R 1, R 2 and R. sup.3 are each independently(a) hydrogen, except that R. sup.1 is other than hydrogen;(b) alkyl, alkenyl, alkynyl, alkoxy, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, aryl, aryloxy, aralkyl or aralkoxy, any of which may be substituted with Z 1, Z 2 and Z. sup.3 ;(c) halo;(d) hydroxyl;(e) cyano; (f) nitro; (g)--C(O)H or--C(O)R 6 ;(h)--CO 2 H or--CO 2 R 6 ; (i)--SH,--S(O) n R 6,--S(O) m--OH,--S(O) m--OR 6,--O--S(O) m--R 6,--O--S(O) m OH or--O--S(O) m--OR. sup.6 ;(j)--Z. sup.4--NR 7 R 8 ; or (k)--Z 4--N(R 11--Z 5--NR 9 R 10 ; and the remaining symbols are as defined in the specification.
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