Asymmetric dihydroxylation of D-glucose derived α, β-unsaturated ester: synthesis of azepane and nojirimycin analogues

The asymmetric dihydroxylation of a D-glucose derived α,β-unsaturated ester 3 afforded syn vicinal diols in good to high diastereoselectivity. The conversion of these vicinal diols to the corresponding cyclic sulfate, regio-, stereoselective nucleophilic ring opening by sodium azide, and LAH reduction afforded amino heptitols 7a,b that were converted to azepane 1c,d and nojirimycin analogues 2c,d

Synthesis of pentahydroxy indolizidine alkaloids using ring closing metathesis: attempts to find the correct structure of uniflorine A

Ring closing metathesis of D-glucose derived diene-substrate containing nitrogen functionality followed by asymmetric dihydroxylation afforded sugar substituted dihydroxylated pyrrolidines 8a-c which on 1,2-acetonide deprotection and reductive amination afforded putative uniflorine A 2a and its analogues 2b-c, respectively

Intramolecular 5-endo-trig aminomercuration of β-hydroxy-γ-alkenylamines: efficient route to a pyrrolidine ring and its application for the synthesis of (+)-castanospermine and analogues

The intramolecular aminomercuration reaction of sugar-derived β-hydroxy-γ-alkenylamines 8a-c undergoes 5-endo-trig cyclization in high yield. The sugar-substituted pyrrolidines thus obtained were elaborated to the synthesis of polyhydroxylated indolizidine alkaloids, namely, castanospermine 1a, 1-epi-castanospermine 1b, and 8a-epi-castanospermine 1c, having promising glycosidase inhibitory activities

Synthesis and evaluation of glycosidase inhibitory activity of N-butyl 1-deoxy-D-gluco-homonojirimycin and N-butyl 1-deoxy-L-ido-homonojirimycin

Conjugate addition of n-butyl amine to d-glucose derived &#945;,&#946;-unsaturated ester 4 afforded &#946;-amino esters 5a,b that on reduction of ester group, 1,2-acetonide deprotection, and reductive amination led to the formation of corresponding N-butyl 1-deoxy-d-gluco-homonojirimycin 2c and N-butyl 1-deoxy-l-ido-homonojirimycin 2d which were found to be selective &#946;-glucosidase inhibitors with an IC<SUB>50</SUB> value in millimolar range

1,3-dipolar cycloaddition reaction of D-glucose-derived nitrone with allyl alcohol: synthesis of 2-hydroxy-1-deoxycastanospermine analogues

The synthesis and evaluation of glycosidase inhibitory activity of polyhydroxylated indolizidine alkaloids namely 2-hydroxy-1-deoxycastanospermine 3a,b and 2-hydroxy-1-deoxy-8a-epi-castanospermine 3c,d is reported. The key step involves the intermolecular 1,3-dipolar cycloaddition of allyl alcohol to d-glucose-derived nitrone 4, followed by tosylation, that afforded four diastereomeric sugar-substituted isoxazolidines 5a-d with the desired regioselectivity. The one-pot conversion of 5a-d to pyrrolidines 8a-d by hydrogenolysis, removal of 1,2-acetonoide functionality, and hydrogenation afforded corresponding target molecules 3a-d

Polyhydroxylated homoazepanes and 1-deoxy-homonojirimycin analogues: synthesis and glycosidase inhibition study

The Johnson-Claisen rearrangement of D-gluco and L-ido-derived allylic orthoesters afforded γ,δ-unsaturated ester that on ester reduction, epoxidation, regioselective oxirane opening by sodium azide and hydrogenation led to sugar amino alcohols-immediate precursors for 1-deoxy-homonojirimycin 3a,b and polyhydroxylated homoazepanes 4a,b. Our synthetic approach and glycosidase inhibitory activity is reported

Synthesis of tetrahydroxy perhydroaza-azulenes: tandem Johnson-Claisen rearrangement of D-glucose-derived allylic alcohols

The Johnson-Claisen rearrangement of D-glucose-derived allylic alcohols 5a,b afforded sugar-substituted γ,δ-unsaturated ester 6 in high yield. Conversion of the ester group to an azidomethyl group, epoxidation of the double bond and hydrogenation gave pyrrolidine ring skeletons 13a and 13b, which were transformed to tetrahydroxy perhydroaza-azulenes 1a and 1b, respectively. Glycosidase inhibitory activity was also evaluated