Inosamines, acetyl

Selective replacement of hydroxyl groups by bromine has been reported for some inositols and inosamines. DL-2-Amino-2-deoxy-epi-inositol hydrochloride plus acetyl bromide in acetic anhydride gave, after 6 hours at 150°, DL-4-acetamido-l,2,6-tri-0-acetyl-3,5-dibromo-3,4,5-trideoxy-c/uro-inositol in 32% yield, the bromine atoms having been introduced with inversion.407 Under related conditions, DL-epi-... 

Aminocyclite (Inosamine) lassen sich selektiv oxydieren, wenn man die Aminogruppe durch geeignete Substituenten wie Carbobenzoxy- oder Acetyl-Gruppen schiitzt. 

In ahnlicher Weise wird auch bei N-Acetyl-l-desoxy-myo-inosamin-4 (72a) und N-Acetyl-l-desoxy-N-methyl-myo-inosamin-4 (72b) nur die axiale Hydroxylgruppe in eine Ketogruppe iibergefiihrt 83, ss). 

Beim N-Acetyl-D,L-inosamin-l (74), das zwei axiale Hydroxyl-gruppen enthalt, wird nur die meta -standige Gruppe angegriffen... 

In all of the deaminations of inosamines just referred to, the substitution product was formed with inversion of configuration, but in no report was a product analysis given, and so, when a product was isolated in low yield, its significance is uncertain. In 1969, Angyal and Murdoch127 made a valuable contribution to these studies when they reported the results of detailed product-analysis for several inosamine deaminations. They confirmed that rearrangement is minimized by the use of O-acetyl derivatives, and their results for equatorial amines are summarized in Table II. The crystalline O-acetyl... 

Deamination of O-Acetylated Inosamines having Equatorially Attached Amino Groups127... 

The rates of displacement of the sulphonate group by azide ion in DMF at 110 °C have been measured for a series of toluene-p-sulphonyl and p-bromo-benzenesulphonyl derivatives of 3-0-methyl-cA/ra-inositol and 4-0-methyl-tf//< -inositol in these compounds, the arylsulphonate group was located at position 4 (or 3), and the substituents at positions 1,2, 5, and 6 were isopropylidene, acetyl, methyl, and cyclic carbonate. All of the resulting azides (except the unreactive penta-O-methyl-c/j/ra derivative) could be converted into one of two inosamine penta-acetates, viz. lL-2-amino-2-deoxy-l-0-methyl-a//o-inositol and 1d-3-amino-3-deoxy-4-0-methyl-c/ /ra-inositol penta-acetates. The results were discussed in terms of currently held views on displacement reactions with carbohydrate and related sulphonates. 

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