Deoxy derivatives, properties

The properties of various flexible 2,3- and 3,4-anhydropyranoses, and their deoxy derivatives have been studied. Methyl 2,3-anhydro-4-... 

The CD and conformational properties of acyclic derivatives of fructose, sorbose, tagatose, and four deoxy derivatives of fructose have been reviewed [14],... 

For over a decade, hormonal activity of any consequence was thought to be limited to steroids containing a A4-3-keto group. A recent development of much interest, therefore, is the removal of the 3-ketone from VIII (R = X = H) via thioketal formation and reduction with sodium in liquid ammonia. Subsequent oxidation and ethinylation afforded the 3-deoxy derivatives of XIII and XV (20). The latter, lynestrenol, possesses marked progestational properties. High potency was also found when the ketone (XV, R = X = H) was reduced... 

Compounds of this class, for example, hexopyranose derivatives having the general formula (123) (see Table II), have most frequently been prepared from the corresponding 6-deoxy-6-iodo or 6-bromo-6-deoxy derivatives of suitably protected aldohexoses or aldohexosides by allowing them to react at room temperature with silver fluoride in pyridine. Alternatively, for example, the 5,6-unsaturated derivative of 1,2 3,4-di-O-iso-propylidene-a-D-galaotopyranose was prepared from the 6-deoxy-6-iodo compound by heating at 130° with sodium methoxide in methanol. Properties of some members of this class are given in Table II. 

Chapter 20, and to n.m.r. spectroscopy of fluorinated oligosaccharides in Chapter 21. The 4.", 6"-dideoxy-4", 6"-difluoro-, 4",6"-di-deoxy-4"-fluoro-, 6"-deoxy-6"-fluoro-, and 6"-deoxy-derivatives of 4"-epi-kanamyoin A have been synthesized from the 4" 6"-ditriflate and 6"-broaylated-4"-triflate derivatives of kanamycin A and their antibacterial properties examined. A discussion of the conversion of hydroxy groups into chloro-, bromo-, and iodo-deoxy groups... 

The chiroptical properties of aldohexono- and aldopentono-1,4-lactones and some of their 2- and 3-deoxy derivatives have been discussed in terms of the conformation of the five-membered lactone ring, It is possible to decide whether these y-Iactones exist in solution in an or Ez conformation from c.d. measurements - for example, o-ribono- and D-allono-1,4-lactones prefer an E conformation (517), while D-talono-l,4-Iactone prefers an conformation (518). 

Amide derivatives have proved especially useful sugars for study by c.d. spectroscopy. The amide substituent is the same as the chromophore found in proteins, so that its optical properties have been extensively studied both experimentally and theoretically. 2-Acetamido sugars are found in many glycoproteins. The structure of 2-acetamido-2-deoxy-a-D-glucopyranose is given as an example in formula 7. 

The taste properties of the di-O-methylhexopyranosyl derivatives, like those of the corresponding deoxy sugars, are never sweet, and always bitter. As with the deoxy sugars, this is possibly the result of increased lipophilicity of the molecule. In sucrose, however, the presence of two methyl groups on the D-glucopyranosyl or the D-fructofuranosyl group does not seem to cause any marked bitterness (see Table XVIII). 

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