113016-74-3

Upstream product

• 67-56-1 methanol 
• 100-39-0 benzyl bromide 
• 87318-96-5 (S)-1-((R)-2,2-Dimethyl-[1,3]dioxolan-4-yl)-pent-4-en-2-ol 
• 14241-58-8 (1R,3S,5S)-6,8-dioxabicyclo[3.2.1]octan-3-ol 
• 95641-15-9 1,6-anhydro-3-O-benzyl-2,4-dideoxy-β-D-threo-hexopyranoside 
• 50880-93-8 levoglucosan tritosylate 
• 32233-44-6 2-[(4S)-2,2-dimethyl-1,3-dioxolan-4-yl]acetaldehyde 

Downstream Products

• 112996-03-9 methyl 2,4-dideoxy-3,6-di-O-benzyl-α- and β-D-threo-hexopyranoside 
• 112996-03-9 methyl 2,4-dideoxy-3,6-di-O-benzyl-α-D-threo-hexopyranoside 
• 112996-05-1 2,4-dideoxy-3,6-di-O-benzyl-α- and β-D-threo-hexopyranoses 
• 88096-46-2 (4S,6S)-4-benzyloxy-6-benzyloxymethyltetrahydropyran-2-one 
• 87319-09-3 (4S,6R)-4-Benzyloxy-6-[2-(tert-butyl-diphenyl-silanyloxy)-ethyl]-2-((Z)-(3S,4R,5S)-4-hydroxy-3,5-dimethyl-hept-1-enyl)-tetrahydro-pyran-2-ol 
• 87319-08-2 (4S,6R)-4-Benzyloxy-6-[2-(tert-butyl-diphenyl-silanyloxy)-ethyl]-2-((3S,4R,5S)-4-hydroxy-3,5-dimethyl-hept-1-ynyl)-tetrahydro-pyran-2-ol 
• 87319-10-6 {2-[(2R,4S,6S,8R,9S)-4-Benzyloxy-8-((S)-sec-butyl)-9-methyl-1,7-dioxa-spiro[5.5]undec-10-en-2-yl]-ethoxy}-tert-butyl-diphenyl-silane 
• 87319-11-7 2-[(2R,4S,6S,8R,9S)-4-Benzyloxy-8-((S)-sec-butyl)-9-methyl-1,7-dioxa-spiro[5.5]undec-10-en-2-yl]-ethanol 
• 87318-95-4 (4S,6R)-4-Benzyloxy-6-[2-(tert-butyl-diphenyl-silanyloxy)-ethyl]-tetrahydro-pyran-2-one 

Relevant academic research and scientific papers

Towards a New Type of HMG-CoA Reductase Inhibitors: Part II: Dramatic Substituent Effects in the C-5 Epimerisation of Carbohydrate Derivatives

In the course of our search for a new class of HMG-CoA reductase inhibitors, the synthesis of reaction intermediate analogues was investigated.Compound 2, having the C-5 (R) configuration of natural mevinic acids, was prepared in enantiomerically pure form starting from levoglucosan.During this synthesis, an epimerisation of the olefinic intermediate 16 was observed and was found to depend strongly both on the axial or equtorial orientation and on the nature of the C-3 substituent.Biological activity of compound 2 is reported.Keywords: HMGCoA reductase, inhibitor, carbohydrate, base catalyzed epimerisation, O-silyl protecting group.

Synthesis of a Structurally Modified Glycal. (-)-(2R,4S)-2-Methyl-2-vinyl-4-(benzyloxy)-3,4-dihydro-2H-pyran

A synthetic procedure for the transformation of levoglucosan (4) to (-)-(2R,4S)-2-methyl-2-vinyl-4-(benzyloxy)-3,4-dihydro-2H-pyran (1) in 11 steps is described.The scheme relies on selective deoxygenation of the pair of α-hydroxyl groups, blocking of the β-hydroxyl, and formation of ester 16.The presence of the carboxylate group allows for stereocontrolled methylation of the enolate anion, conversion of ester to vinyl, and ultimate eliminative removal of the methoxyl substituent in methyl glycoside 25.This key transformation takes advantage of regioselective acetal cleavage by trimethylsilyl iodide and in situ dehydroiodination of the product so formed with hexamethyldisilazane.Certain unsuccessful attempts to form the α-lithio anion of 1 are also discussed.

Preparation of a Chiral Lactone from Leavoglucosan; a Key Intermediate for Synthesis of the Spiroacetal Moietes of the Avermectins and Milbemycins

A synthesis of two diprotected (4S,6S)-4-hydroxy-6-hudroxymethyltetrahydropyran-2-ones has been developed from laevoglucosan.Reaction of these lactones with a substituted chiral lithium acetylide followed by hydrogenation and acid-catalysed cyclisation led to formation of the spiroacetal moiety of milbemycin α1 and α3.The acetylene was prepared by resolution of racemic material obtained from reaction of lithium acetylide and cis-butene epoxide.Alternatively a stereocontrolled synthesis was developed from (S)-methyl-3-hydroxy-2-methylpropionate which involved 'chelation controlled' addition of lithium dimethylcuprate to the corresponding tetrahydropyranyloxy aldehyde.

Stereocontrolled Synthesis of the Spiro Ketal Unit of Avermectin B1a Aglycon

A stereocontrolled total synthesis of the 1,7-dioxaspiroundecene subunit of the avermectin B1a aglycon is presented based on the "chiron" approach which utilizes optically active starting materials.