701-81-5Relevant academic research and scientific papers
PHENYL SULFONAMIDE ENDOTHELIN ANTAGONISTS
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, (2008/06/13)
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.
Distinction between polar and electron-transfer routes. A mechanistic study on the wittig reactions of nonstabilized ylides
Yamataka, Hiroshi,Nagareda, Katsushi,Takatsuka, Tsutomu,Ando, Katsuhiro,Hanafusa, Terukiyo,Nagase, Shigeru
, p. 8570 - 8576 (2007/10/02)
The Wittig reaction of nonstabilized ylides with benzaldehyde and benzophenone was investigated in detail by means of carbonyl-14C kinetic isotope effects, substituent effects, and isotope-scrambling and probe experiments. The reaction with benzophenone gave the carbon isotope effects and the Hammett ρ values of considerable magnitude both in Li salt-free and salt-present conditions. In contrast, they are quite small for the reaction with benzaldehyde. Enone-isomerization and dehalogenation probe experiments indicated that the nonstabilized ylide has enough ability to transfer an electron to benzaldehyde and benzophenone. These results were interpreted in a self-consistent manner by the mechanism that the Wittig reaction of nonstabilized ylides proceeds via initial electron transfer from the ylide to the carbonyl compounds. The electron-transfer step is rate-determining for benzaldehyde, while radical coupling following the electron-transfer step is rate determining for benzophenone. From the probe experiments together with the isotope effects and the substituent effects reported previously, the reaction of semistabilized ylides was concluded to proceed through a polar nucleophilic addition mechanism.
