New Methods of Preparative Organic Chemistry IV . Cyclization of Dialdehydes with Nitromethane

Condensation of nitromethane with suitable diadehydes in alkaline medium provides a general method of cyclization, in which the methyl group of the nitromethane is incorporated into the ring. This method leads to 5‐, 6‐, and 7‐membered rings and is equally applicable to aliphatic, aromatic, and sugar dialdehydes. For example, glyoxal is converted into 1,4‐dideoxy‐1,4‐dinitro‐neo‐inositol, and glutaraldehyde into trans‐2‐nitrocyclohexane‐1,3‐diol, while the corresponding cyclization of xylo‐trihydroxyglutaraldehyde leads to deoxy‐nitroinositols having the scyllo, myo‐1, and muco‐3 configurations.‐In the case of aromatic dialdehydes, the cyclization is accompanied by elimination of water. Thus, phthalaldehyde, naphthalene‐2,3‐dicarboxaldehyde, and homophthalaldehyde yield, respectively, 2‐nitroindenol, 2‐nitrobenzindenol, and 2‐nitronaphthalene. ‐Application of the method to sugar dialdehydes (aldehydic diglycol derivatives of monosaccharides formed by periodate oxidation) constitutes an excellent synthesis of 3‐amino sugars, since 3‐deoxy‐3‐nitropyranoses are formed smoothly on cyclization, and the corresponding 3‐amino derivatives are obtained by hydrogenation. Thus, the reaction sequence: periodate oxidation → cyclization with nitromethane → hydrogenation, leads in the case of α‐and β‐ D ‐pentosides to 3‐amino‐3‐deoxy‐ D ‐and‐ L ‐pentosides, respectively, with ribo, xylo, and arabino configurations. α‐ D ‐hexosides give derivatives with gluco, manno, and galacto configurations. 3‐Amino‐3,6‐dideoxyglucosides of the D ‐and L ‐series are obtained from 6‐deoxy‐ D ‐or‐ L ‐hexosides, respectively, and 3‐aminohexosans with gulo, ido, and altro configurations are obtained from 1,6‐anhydro sugars. Cyclization of the dialdehydes obtained from sedoheptulose and methyl 4,6‐O‐ethylidene‐α‐ D ‐glucoside by periodate oxidation, leads to 3‐nitro and, after hydrogenation, to 3‐amino derivatives of 3‐deoxyheptopyranoses.