Synthesis of new glycosyl biuret and urea derivatives as potential glycoenzyme inhibitors

Glucose derived inhibitors of glycogen phosphorylase

“…These side reactions could be circumvented by the addition of unprotected b-D-glucopyranosylamine obtained in situ from b-D-glucopyranosylammonium carbamate [46] (25) to various acyl-isocyanates to give directly the unprotected 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 27 ureas [45]. Biurets 28 [47] and 29 [42] were prepared in reactions of urea 26 with phenyl and 2-naphthoyl isocyanates, respectively.…”

Efficient preparation of β-d-glucosyl and β-d-mannosyl ureas and other N-glucosides in carbohydrate melts

“…13 C-NMR and NOE experiments (see the ESI †) confirmed the expected b-anomer as the reaction product, and the mass spectrometry analysis indicated that selective mono-condensation had taken place. Again, the reduced electronegativity and bulkiness of the urea moiety are the probable reason for the observed stereochemistry.…”

“…After stirring the melts with acidic Amberlyst 15 at 80 • C for 2 h, reaction control by 13 C-NMR showed that the 12 signals of the corresponding starting materials were reduced to 6 signals. As in the case of glucosyl-and mannosyl urea, the resonance signal for the anomeric centre disappeared and a new carbonyl resonance was detected at 160 ppm (D 2 O).…”

Acyclic and Cyclic Ureas (Update 2013)

“…Subsequent substitution of the phenolate group with an amine then yields the corresponding biuret. Both methods have been used, for example for the preparation of glycosyl biurets [296,297] or potentially pharmacologically active compounds. [298] Another method of biuret preparation involves reaction between nitrobiuret and amines at elevated temperatures.…”