Aminocyclitols. III. Synthesis of diaminocyclohexanediols

Reaction of N,N′-diethoxycarbonyl-2,5-dideoxystreptamine (1b) with thionyl chloride produced the iminoether dihydrochloride 8 which, upon simple treatment with water gave the di-N,O-carbonyl compound 9. Acidic hydrolysis of 9 yielded the aminocyclitol 2a. Alternatively, 2a was prepared from N,N′-dibenzoyl-2,5-dideoxystreptamine (1c) via the oxazoline 10 followed by acidic hydrolysis. Treatment of 1c with triethyl orthoacetate in the presence of boron trifluoride etherate produced the oxazoline 11 and the latter product was hydrolyzed to give 3a. By the same reaction sequence, 1e and 1h were converted to the oxazolines 12 and 13 which upon acidic hydrolysis provided the enantiomeric aminocyclitols 4 and 5. Ring-opening reactions of cis- and trans-1,4-diepoxycyclohexanes (14 and 16) with sodium azide to the diazido compounds 15 and 17, followed by reduction, afforded the aminocyclitols 6 and 7.