Preparation of Unsymmetrically Labeled Hydroperoxides. A Hydroxamate Ester−Nitrosation Approach
摘要:
Reaction of O-tertiary alkyl arylhydroxamate esters with nitrosyl chloride gives O-tertiary alkyl aryl peresters that can be hydrolyzed to the hydroperoxide. If the hydroxamate ester carbonyl oxygen or nitrosyl chloride is labeled with O-18, the label appears in the product hydroperoxide's terminal oxygen. This strategy, which derives from the pioneering work of Koenig, permits the preparation of a variety of(2-O-18) hydroperoxides, including tertiary alkyl and cumyl hydroperoxides. tert-Butyl alpha-hydroperoxyisobutyrate, 27, prepared in this way with an O-18 label in the terminal oxygen, serves as a useful precursor for the preparation of other unsymmetrically labeled peroxides and hydroperoxides. Hydroperoxide 27 is protected as a perketal with 2-methoxypropene, and a six-step sequence involving Dibal-H reduction, oxidation (PDC), and Wittig chemistry provides the allylic hydroperoxide 12 that is used in mechanistic studies. Hydroxamate esters that give peresters prone to undergo the Criegee rearrangement upon reaction with NOCl do not give useful yields of product hydroperoxides in the transformation and one hydroxamate ester 17 that reacts via an allylalkoxyl radical gives epoxides 20a and 20b as the major isolable products of reaction.
We report the synthesis and biological properties of novel inhibitors of the Na(+),K(+)-ATPase as positive inotropic compounds. Following our previously described model from which Istaroxime was generated, the 5alpha,14alpha-androstane skeleton was used as a scaffold to study the space around the basic chain of our lead compound. Some compounds demonstrated higher potencies than Istaroxime on the receptor
AMINO DERIVATIVES OF ANDROSTANES AND ANDROSTENES AS MEDICAMENTS FOR CARDIOVASCULAR DISORDERS
申请人:Cerri Alberto
公开号:US20110053902A1
公开(公告)日:2011-03-03
Compounds of formula (I) wherein: the groups are as defined in the description, are useful for the preparation of medicaments for the treatment of cardiovascular disorders, in particular heart failure and hypertension. The compounds are inhibitors of the enzymatic activity of the Na
+
, K
+
-ATPase. Said compounds are used for the preparation of a medicament for the treatment of a disease caused by the hypertensive effects of endogenous ouabain, such as renal failure progression in autosomal dominant polycystic renal disease (ADPKD), preeclamptic hypertension and proteinuria and renal failure progression in patients with adducin polymorphisms.
Preparation of Unsymmetrically Labeled Hydroperoxides. A Hydroxamate Ester−Nitrosation Approach
作者:Ned. A. Porter、Sarah E. Caldwell、Jennifer R. Lowe
DOI:10.1021/jo980654e
日期:1998.8.1
Reaction of O-tertiary alkyl arylhydroxamate esters with nitrosyl chloride gives O-tertiary alkyl aryl peresters that can be hydrolyzed to the hydroperoxide. If the hydroxamate ester carbonyl oxygen or nitrosyl chloride is labeled with O-18, the label appears in the product hydroperoxide's terminal oxygen. This strategy, which derives from the pioneering work of Koenig, permits the preparation of a variety of(2-O-18) hydroperoxides, including tertiary alkyl and cumyl hydroperoxides. tert-Butyl alpha-hydroperoxyisobutyrate, 27, prepared in this way with an O-18 label in the terminal oxygen, serves as a useful precursor for the preparation of other unsymmetrically labeled peroxides and hydroperoxides. Hydroperoxide 27 is protected as a perketal with 2-methoxypropene, and a six-step sequence involving Dibal-H reduction, oxidation (PDC), and Wittig chemistry provides the allylic hydroperoxide 12 that is used in mechanistic studies. Hydroxamate esters that give peresters prone to undergo the Criegee rearrangement upon reaction with NOCl do not give useful yields of product hydroperoxides in the transformation and one hydroxamate ester 17 that reacts via an allylalkoxyl radical gives epoxides 20a and 20b as the major isolable products of reaction.