Hence, unless the radical introduced be one which exercises a special attractive influence, substitution should take place in preference in the previously unsubstituted ring.
The new protocol accounts for the reversal in selectivity observed in changing from Z enol borinates to unsubstituted enol borinates to unsubstituted enol borinates.
However, the unsubstituted nucleosides could lightly yield the fragment ions of the nucleoside base and sugar ring.
It may be generally concluded that the substitution of alkyl, nitro, hydroxyl, and haloid groups for hydrogen in a molecule occasions a deformation of crystal structure in one definite direction, hence permitting inferences as to the configuration of the atoms composing the crystal; while the nature and degree of the alteration depends (1) upon the crystal structure of the unsubstituted compound; (2) on the nature of the substituting radicle; (3) on the complexity of the substituted molecule; and (4) on the orientation of the substitution derivative.