Palladium catalyzed C<sub>sp2</sub>–H activation for direct aryl hydroxylation: the unprecedented role of 1,4-dioxane as a source of hydroxyl radicals
作者:Kapileswar Seth、Manesh Nautiyal、Priyank Purohit、Naisargee Parikh、Asit K. Chakraborti
DOI:10.1039/c4cc06864e
日期:——
Direct aryl hydroxylation has been achieved via palladium-catalysed Csp2–H activation using versatile directing groups through unprecedented hydroxyl transfer from 1,4-dioxane.
Synthesis, structures and speciation studies of ruthenium(<scp>iii</scp>) hydroxamate/hydroximato complexes. Crystal and molecular structure of hydrated [Ru(H<sub>2</sub>edta)(2-methoxyphenylhydroxamate)], the first structurally characterised ruthenium(<scp>iii</scp>)–hydroxamate complex
作者:Jedd Comiskey、Etelka Farkas、Krystyna A. Krot-Lacina、Robin G. Pritchard、Charles A. McAuliffe (the late)、Kevin B. Nolan
DOI:10.1039/b310193m
日期:——
first reported structure of a Ru(III)–hydroxamate, the carboxylato groups of the tetradentate H2edta are trans to each other and the amino nitrogen and hydroxamate oxygen donor atoms are roughly coplanar. Relevant bond lengths (Å) are: Ru–O(carboxylato) 2.016(4) and 2.044(3), Ru–O(hydroxamato O−) 1.964(4), Ru–O (hydroxamato CO) 2.019(4), Ru–N 2.060(4) and 2.156(4). Addition of R-PhaH to an aqueous solution
K [Ru(Hedta)Cl]·1.5H 2 O与各种苯基异羟肟酸R-PhaH在水溶液中反应,得到异羟肟酸酯络合物[Ru(H 2 edta)(R-Pha)]· x H 2 O,已经确定其中之一即水合的[Ru(H 2 edta)(2-OMe-Pha)]的晶体和分子结构,其中2-OMe-Pha = 2-甲氧基苯基异羟肟酸酯。在这个复合物中,Ru(III)–的第一个报告结构异羟肟酸酯中,四齿H的羧酸根基团2 EDTA是反式于彼此和氨基 氮和异羟肟酸酯的氧供体原子大致共面。相关的键长(A)为:钌-O(羧酸根)2.016(4)和2.044(3),RU-O(hydroxamatoø -)1.964(4),RU-O(hydroxamato CO)2.019(4),钌–N 2.060(4)和2.156(4)。在K [Ru(Hedta)Cl]·1.5H 2 O的水溶液中添加R-PhaH导致[Ru(edta)(R-Pha)]
Hydroxamic acid and its derivatives as inhibitors of melanocyte tyrosinase for topical skin lighteners
申请人:Integriderm, Inc.
公开号:US20030199558A1
公开(公告)日:2003-10-23
Methods, compounds, and formulations are provided to reduce pigmentation in mammalian skin, comprising hydroxamic acid and its derivatives, and especially benzohydroxamic acid and its derivatives. The compounds preferably inhibit pigment synthesis in melanocytes through inhibition of melanocyte tyrosinase. The methods can be used for lightening skin, and for treating uneven skin complexions, which result from hyperpigmentation-related medical conditions such as melasma, age spots, freckles, ochronosis, and lentigo. The compounds can be used medically or cosmetically, and preferably as topical formulations.
This invention relates to compounds of formula I their salts, and pharmaceutically acceptable derivatives thereof, pharmaceutical compositions comprising these compounds and their use in the treatment of picornavirus infections in mammals as well as novel intermediates useful in the preparation of the compounds of formula I.
This invention relates to compounds of formula I
their salts, and pharmaceutically acceptable derivatives thereof, pharmaceutical compositions comprising these compounds and their use in the treatment of picornavirus infections in mammals, as well as novel intermediates useful in the preparation of the compounds of formula I.