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Glycosylidene Carbenes. Part 5. Synthesis of Glycono‐1,5‐lactone Tosylhydrazones as Precursors of Glycosylidene Carbenes
Author(s) -
Mangholz Sissi E.,
Vaseha Andrea
Publication year - 1991
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19910740845
Subject(s) - chemistry , anomer , acrylonitrile , carbene , pyridinium , oxidizing agent , medicinal chemistry , glycoside , organic chemistry , photodissociation , catalysis , polymer , copolymer
The benzyl‐ and the acyl‐protected glyconolactone tosylhydrazones 6 , 9 , 12 , 16 , and 19 ( Scheme 1 ) were prepared in good yields by treating the hemiacetals 4 , 7 , 10 , 14 , and 17 with N ‐tosylhydrazine, to give the N ‐glycosylhydrazines 5 , 8 , 11 , 15 , and 18 , and by oxidizing these hydraz tries with N ‐bromosuccinimide (NBS) in the presence of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU), with CrO 3 –dipyridine complex or with pyridinium dichromate. Photolysis of the sodium sail 20 of 6 ( Scheme 2 ) in the presence of N ‐phenylmaleimide, dimethyl fumarate, or acrylonitrile gave the corresponding cyctopropanes 21 – 28 in satisfactory yields. Phololytic or thermolytic glycosidation of phenol and 4‐melhoxyphenol by 20 yielded the anomeric glycosides 29 / 30 and 31 / 32 , yields being marginally higher for the Ihermolytic process. Phololytic glycosidation of propan‐2‐ol gave the glycosides 33 and 34 in low yields only. Yields and ratios of products were compared to those obtained with the diazirine 1 as a source of glycosylidene carbenes. While the yields from 20 are lower, the ratios of products obtained in the photolytic reactions are in agreement with the formation of a common intermediate from both carbene precursors.