PubMed:2765031 JSONTXT

{"target":"https://pubannotation.org/docs/sourcedb/PubMed/sourceid/2765031","sourcedb":"PubMed","sourceid":"2765031","source_url":"http://www.ncbi.nlm.nih.gov/pubmed/2765031","text":"Preparation and calculated conformations of the 2'-, 3'-, 4'-, and 6'-deoxy, 3'-O-methyl, 4'-epi, and 4'- and 6'-deoxy-fluoro derivatives of methyl 4-O-alpha-D-galactopyranosyl-beta-D-galactopyranoside (methyl beta-D-galabioside).\nThe glycosyl chlorides of the 3-O-methyl (6) and 4-deoxy-4-fluoro (8) O-benzylated derivatives of D-galactopyranose and 2,3,4,6-tetra-O-benzyl-D-glucopyranose were condensed with methyl 2,3,6-tri-O-benzoyl-beta-D-galactopyranoside to give, after deprotection, the 3'-O-methyl (23), 4'-deoxy-4'-fluoro (25), and 4'-epi (27) derivatives, respectively, of methyl beta-D-galabioside (1). The glycosyl fluorides of 2,3,4-tri-O-benzyl-D-fucopyranose and the 3-deoxy (12) and 4-deoxy (16) O-benzylated derivatives of D-galactopyranose were condensed with methyl 2,3,6-tri-O-benzyl-beta-D-galactopyranoside (21), to give, after deprotection, the 6'-deoxy (31), 3'-deoxy (34), and 4'-deoxy (37) derivatives of 1, respectively. The 2'-deoxy (41) derivative of 1 was prepared by N-iodosuccinimide-induced condensation of 3,4,6-tri-O-acetyl-D-galactal and 21 followed by deprotection. Treatment of methyl 2,3,6-tri-O-benzoyl-4-O-(2,3-di-O-benzoyl-alpha-D-galactopyranosyl)-beta -D- galactopyranoside with Et2NSF3 (DAST), followed by deprotection, provided the 6'-deoxy-6'-fluoro (46) derivative of 1. Molecular mechanics calculations yielded conformations for 23, 25, 27, 31, 34, 37, 41, and 46 with small deviations from the calculated conformation for 1 (phi H/psi H: -40 degrees/-6 degrees).","tracks":[{"project":"sentences","denotations":[{"id":"TextSentencer_T1","span":{"begin":0,"end":230},"obj":"Sentence"},{"id":"TextSentencer_T2","span":{"begin":231,"end":614},"obj":"Sentence"},{"id":"TextSentencer_T3","span":{"begin":615,"end":948},"obj":"Sentence"},{"id":"TextSentencer_T4","span":{"begin":949,"end":1103},"obj":"Sentence"},{"id":"TextSentencer_T5","span":{"begin":1104,"end":1319},"obj":"Sentence"},{"id":"TextSentencer_T6","span":{"begin":1320,"end":1513},"obj":"Sentence"},{"id":"T1","span":{"begin":0,"end":230},"obj":"Sentence"},{"id":"T2","span":{"begin":231,"end":614},"obj":"Sentence"},{"id":"T3","span":{"begin":615,"end":948},"obj":"Sentence"},{"id":"T4","span":{"begin":949,"end":1103},"obj":"Sentence"},{"id":"T5","span":{"begin":1104,"end":1319},"obj":"Sentence"},{"id":"T6","span":{"begin":1320,"end":1513},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"attributes":[{"subj":"TextSentencer_T1","pred":"source","obj":"sentences"},{"subj":"TextSentencer_T2","pred":"source","obj":"sentences"},{"subj":"TextSentencer_T3","pred":"source","obj":"sentences"},{"subj":"TextSentencer_T4","pred":"source","obj":"sentences"},{"subj":"TextSentencer_T5","pred":"source","obj":"sentences"},{"subj":"TextSentencer_T6","pred":"source","obj":"sentences"},{"subj":"T1","pred":"source","obj":"sentences"},{"subj":"T2","pred":"source","obj":"sentences"},{"subj":"T3","pred":"source","obj":"sentences"},{"subj":"T4","pred":"source","obj":"sentences"},{"subj":"T5","pred":"source","obj":"sentences"},{"subj":"T6","pred":"source","obj":"sentences"}]},{"project":"NCBITAXON","denotations":[{"id":"T1","span":{"begin":359,"end":366},"obj":"OrganismTaxon"}],"attributes":[{"id":"A1","pred":"db_id","subj":"T1","obj":"100829"},{"subj":"T1","pred":"source","obj":"NCBITAXON"}]}],"config":{"attribute types":[{"pred":"source","value type":"selection","values":[{"id":"sentences","color":"#9398ec","default":true},{"id":"NCBITAXON","color":"#b2ec93"}]}]}}