PubMed:16182263 JSONTXT

{"project":"sentences","denotations":[{"id":"TextSentencer_T1","span":{"begin":0,"end":146},"obj":"Sentence"},{"id":"TextSentencer_T2","span":{"begin":147,"end":423},"obj":"Sentence"},{"id":"TextSentencer_T3","span":{"begin":424,"end":554},"obj":"Sentence"},{"id":"TextSentencer_T4","span":{"begin":555,"end":686},"obj":"Sentence"},{"id":"T1","span":{"begin":0,"end":146},"obj":"Sentence"},{"id":"T2","span":{"begin":147,"end":423},"obj":"Sentence"},{"id":"T3","span":{"begin":424,"end":554},"obj":"Sentence"},{"id":"T4","span":{"begin":555,"end":686},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"text":"Stable spiro-endoperoxides by sunlight-mediated photooxygenation of 1,2-O-alkylidene-5(E)-eno-5,6,8-trideoxy-alpha-D-xylo-oct-1,4-furano-7-uloses.\nSunlight-mediated photooxygenation of 3-O-acetyl and 3-O-methyl derivatives of 1,2-O-alkylidene-5(E)-eno-5,6,8-trideoxy-alpha-D-xylo-oct-1,4-furano-7-uloses (1a-e) in carbon tetrachloride solution gave stable 4,7-epidioxy derivatives in 4R (2a-e) and 4S (3a-e) configurations. The presence of an endo alkyl, on the 1,2-O-alkylidene group and its size, resulted in an increase of the yield of the 4S isomers. 3-O-acetyl derivatives yielded products as a mixture of C-7 anomers, whereas 3-O-methyl derivatives gave pure single stereoisomers."}