Hexitols 1,6-imino

To summarize, crystalline l,4-dideoxy-l,4-imino-hexitols are readily prepared from 2,6-dibromo-2,6-dideoxy-hexonolactones in gram quantities without any use of chromatographic separations. The bromolactones may, prior to treatment with aqueous ammonia, either be converted into the 2,3-epoxides by treatment with KF or K2CO3 in acetone, or may be reduced with sodium borohydride in water to give the bromodeoxyhexitols. 

The l,2,6-trideoxy-l,6-imino-D-ara6m<9-hexitol was found to inhibita-D-glucosidase (Ki 12 pM, Bakers yeast), (3-D-glucosidase (Ki 51 pM, Almonds) and (3-D-galactosidase (Ki 13 pM, E. coli) as well, indicating the flexibility of the 7-membered ring system (14). 

Evaluation of nine l,4-dideoxy-l,4-imino-hexitols, prepared by strategies I and II, are reported elsewhere (2,12). Among other results, some interesting (22) and selective (72) a-D-mannosidases were found. 

The synthesis of 2,5-dideoxy-2,5-imino-D-ahro-hexitols 45 and 3,6-dideoxy-... 

The N-linked pseudo-disaccharide 132 has been prepared from imino-D-altro-hexitol 45 (Section 1.3.1) and this compound was found to be a potent inhibitor of P-galactosidase Ki 3.3 pm). ... 

In the synthesis of a Sialyl Lewis X analogue, l,4,5,6-tetradeoxy-l,4-imino-D-ido-hexitol (for synthesis see Section 1.3.1) was a-L-fucosylated at the less hin> dered (C-2) hydroxyl, then p-D-galactosylated at 0-3 to produce a non-sulfated precursor to the pseudo-trisaccharide 137. ... 

The preparation of deoxynojirimycin derivatives incorporating an imidazole ring is mentioned in Chapter 10 and quaternary 2,5-imino-hexitol derivatives are covered in Chapter 24. 

Galactosylated Mn porphyrins 277 have been prepared as catalysts for asymmetric epoxidation, affording predominantly epoxides of R) configuration from styrenes in up to 23% c.c.125 The apap, oa P and aaaP atropisomos of 277 were isolated. Homochiral C2-symmetric quaternary ammonium salts, e.g. 278, have been prepared from chiral 2,S-imino-hexitols as chiral phase transfer catalysts. However, these were found to give only low asymmetric induction in asymmetric epoxidation and Darzens condensations. 

Reaction of (R)/(S)-3-cyano-2-hydroxypropanal with lithium hydroxypyruvate under trans ketolase control followed by a palladium catalyzed-reductive amination afforded l,2,5-trideoxy-l,5-imino-D-arabi o-hexitol (fagomine) ... 

Treatment of 2,5-anhydro-3,4-di-0-benzyl-1 -deoxy-1 -tritylamino-D-glucitol with mesyl chloride, tosic acid-methanol, triethylamine then hydrogen-palladium catalyst affords the 1,6-imino-bridged derivative The reaction of l,2 5,6-dianhydro-3,4-0-isopropylidene-D-mannitol with ben-zylamine followed by deprotection leads only to the seven-membered azepane 52 in high yield. Other l,2 5,6-dianhydro-3,4-0-isopropylidene hexitols gave similar results. No six-membered ring products were detected as is the case with 1,2 5,6-dianhydro-3,4-di-( -benzyl-D-mannitol (see Vol. 28, p. 230, ref. 63). ... 

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