benzyl 3,5-di-O-benzyl-2-deoxy-1,4-dithio-d-erythro-pentofuranoside → 3',5'-di-O-benzyl-4'-thio-thymidine

HRID 1707951Notes

Reaction equation

HRID 1707951 reaction equation
[CH2:1]([O:8][C@@H:9]1[C@@H:21]([CH2:22][O:23][CH2:24][C:25]2[CH:30]=[CH:29][CH:28]=[CH:27][CH:26]=2)[S:20][CH:11](SCC2C=CC=CC=2)[CH2:10]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[Si]([N:35]1[C:40](=[O:41])[C:39]([CH3:42])=[CH:38][N:37]([Si](C)(C)C)[C:36]1=[O:47])(C)(C)C>C(=O)([O-])[O-].[Cd+2].C1(C)C=CC=CC=1>[CH2:1]([O:8][C@@H:9]1[C@@H:21]([CH2:22][O:23][CH2:24][C:25]2[CH:26]=[CH:27][CH:28]=[CH:29][CH:30]=2)[S:20][C@@H:11]([N:37]2[CH:38]=[C:39]([CH3:42])[C:40](=[O:41])[NH:35][C:36]2=[O:47])[CH2:10]1)[C:2]1[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=1

Participants

5

Reactant 2

HCID 11026498benzyl 3,5-di-O-benzyl-2-deoxy-1,4-dithio-d-erythro-pentofuranosideHCID 11807780Bis-trimethylsilyl-thymine

Product 1

HCID 108954453',5'-di-O-benzyl-4'-thio-thymidine

Reagents, catalysts & solvents 2

HCID 10564Cadmium carbonate (CdCO3)CatalystHCID 1140TolueneSolvent

Procedure

A suspension of benzyl 3,5-di-O-benzyl-2-deoxy-1,4-dithio-D-erythro-pentofuranoside (22.5 g, 51.6 mmol), bis TMS-thymine (46 g, 170 mmol), mercuric bromide (20.5 g, 56.7 mmol), cadmium carbonate (29.3 g, 170 mmol) and dry toluene (1 L) was boiled under reflux, with stiring, for 24 hours. The hot mixture was then filtered and the solids were washed with toluene. The filtrate was successively washed with potassium iodide solution (30%) and water and then evaporated. The residue was taken up in 4:1 methanol-water, stirred for 30 minutes, the suspension filtered and the filtrate evaporated. The residue was applied to a silica gel column (hexane-ethyl acetate (1:1)) and combination of the appropriate fractions gave the title product as a clear colourless syrup. 1H NMR indicated the ratio of α- to β- anomers to be 2.8:1. Further column chromatography gave more of the separated anomers. The first compound to be eluted from the column was 3',5'-di-O-benzyl-4'-thio-thymidine as a colourless syrup. This could be crystallised from methanol to give colourless crystals m.p. 140°-142° C.

Workup

  1. temperatureunder reflux, with stiring, for 24 hours
  2. filtrationThe hot mixture was then filtered
  3. washthe solids were washed with toluene
  4. washThe filtrate was successively washed with potassium iodide solution (30%) and water
  5. customevaporated
  6. filtrationthe suspension filtered
  7. customthe filtrate evaporated

Sources & evidence

ORD record
ord-6590732d98d64fbdad87184254b2f8e8
Source dataset
uspto-grants-1994_10
Patent number
US05356882

Reaction notes

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