Spectinomycin modification. II. Spectinomycin C-3'-modification via diazoketone intermediates.

The C-3'-carbonyl group of N-protected spectinomycin is efficiently converted into a diazo group via base treatment of the corresponding tosylhydrazone. The diazo group imparts a new synthetically useful reactivity pattern on the sugar ring of the molecule. The synthesis of C-3'-deoxo-, monohalo- and dihalospectinomycins via the intermediacy of these diazo compounds is described. The reduced bioactivity of these analogs as compared to the parent and the C-3'-dihydro and aminospectinomycins established the need for hydrogen bonding groups in this region of the molecule for good activity, further refining the structure activity relationships in the spectinomycin series.