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Chain Compounds methanesulfonyl

An aryl carbamate replaces the tyrosine moiety in a related analogue. The preparation of this compound first involves activation of the side-chain oxygen in the same oxazole used above (21) by conversion to its mesylate (21a) by means of methanesulfonyl chloride. This intermediate... [Pg.46]

The search for endothelin antagonists as potential compounds for treating cardiovascular disease was noted in Chapter 5 (see atrasentan). A composed with a considerably simpler structure incorporates a pyrimidine ring in the side chain. Condensation of benzophenone (94) with ethyl chloro-acetate and sodium methoxide initially proceeds to addition of the enolate from the acetate to the benzophenone carbonyl. The aUcoxide anion on the first-formed quaternary carbon then displaces chlorine on the acetate to leave behind the oxirane in the observed product (95). Methanolysis of the epoxide in the product in the presence of boron triflor-ide leads to the ether-alcohol (96). Reaction of this with the pyrimidine (97) in the presence of base leads to displacement of the methanesulfonyl group by the aUcoxide from 96. Saponification of the ester group in that product gives the corresponding acid, ambrisentan (98). " ... [Pg.126]

The replacement of a carboxylic acid group by nitrile functionality can also be used for the preparation of labeled compounds, and conditions for alkaline hydrolysis which did not lead to conjugation in skipped dienes like linoleic acid were developed by the Barton group. In this case, the free-radical chain sequence is straightforward, with the methanesulfonyl (or p-toluenesulfonyl) radical acting as the chain carrier [26], This methodology also represents an interesting way for the preparation of nitriles without the necessity for amide formation followed by dehydration. [Pg.122]

The three methanesulfonyl derivatives, sulfur, selenium, and tellurium dimethanethiosulfonates, are isomorphous. Structure analyses have been carried out, starting with tellurium dimethanethiosulfonate and using tellurium as a heavy atom in the first stages. So far, the structure of the tellurium compound has been published in detail 128), and an electron density projection along the short crystal axis of the trisulfide (98) has shown the unbranched sulfur chain structure. [Pg.252]


See other pages where Chain Compounds methanesulfonyl is mentioned: [Pg.267]    [Pg.773]    [Pg.24]    [Pg.69]    [Pg.128]    [Pg.282]    [Pg.358]    [Pg.436]    [Pg.535]    [Pg.166]    [Pg.251]    [Pg.16]    [Pg.400]    [Pg.426]    [Pg.9]    [Pg.17]   


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