A convenient and high yielding method for the cleavage and scavenging of p-methoxybenzyl protecting group of several alcohols using tert-butyl bromide in refluxing acetonitrile is described. Under these mild conditions other protecting groups such as acid sensitive allyl, benzyl, and Me3CPh2Si ethers, or isopropylidene acetals were unchanged. Interestingly, a selective alkoxy-PMB cleavage was observed
作者:Danielle L. Aubele、Christopher A. Lee、Paul E. Floreancig
DOI:10.1021/ol0359259
日期:2003.11.1
are employed as oxocarbenium ion progenitors and allylsilanes are used as nucleophiles. Cyclizations proceed efficiently inside Lewis acidic micelles in water, demonstrating that colloidal suspensions can protect highly electrophilic intermediates from hydrolysis. Reactions are experimentally facile and useful in the preparation of a variety of vinyl- and aryl-substituted tetrahydropyrans with excellent
Benzodioxane prostacyclin analogs represented by the formula: ##STR1## wherein R.sub.1 is alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, or phenoxyalkyl; R.sub.2 is hydrogen, lower alkyl, or aralkyl; R.sub.3 is hydrogen or a protecting group; A is ethylene or vinylene; and the wavy line indicates .alpha. or .beta. configuration or their mixture; or a salt thereof having an antiulcer activity and platelet aggregation inhibitory activity.
Benzodioxane prostacyclin analogues, their preparation and use
申请人:SHIONOGI SEIYAKU KABUSHIKI KAISHA
trading under the name of
SHIONOGI & CO. LTD.
公开号:EP0297923A1
公开(公告)日:1989-01-04
Benzodioxane Prostacyclin Analogues represented by the formula:
wherein R₁ is alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, or phenoxyalkyl; R₂ is hydrogen, lower alkyl, or aralkyl; R₁ is hydrogen or protecting group; A is ethylene or vinylene; and the wavy line indicates α or β configuration or their mixture; or a salt thereof having an antiulcer activity and platelet aggregation inhibitory activity.