Aminomethyl cycloalkanes

The original Demjanov reaction is the conversion of an aminomethyl-cycloalkane into a cycloalkanol consisting of a carbocyclic ring that is expanded by one carbon center e.g. the reaction of aminomethylcyclohexane 8 with nitrous acid leads to formation of cycloheptanol 9 ... 

Reduction of cycloalkane-condensed 2-phenyl-5,6-dihydro-4//-l,3-benzoxazines 144 with lithium aluminium hydride (LAH) afforded A -benzyl-substituted 2-(aminomethyl)cycloalkanols 145 in a reductive ring opening via the ring-chain tautomeric tetrahydro-l,3-oxazine intermediates. Catalytic reduction of 1,3-oxazines 144 under mild conditions in the presence of palladium-on-carbon catalyst similarly resulted in formation of the A -benzyl-1,3-amino alcohols 145. When the catalytic reduction was performed at elevated temperature at hydrogen pressure of 7.1 MPa, the N-unsubstituted 2-(aminomethyl)cycloalkanols 146 were formed in good yields (Scheme 22) <1998SC2303>. 

The range of amines includes normal and branched-chain alkylamines (e.g. isopropylamine), diaminoalkanes (ethylenediamine, propanediamine and their substituted derivatives), heterocyclic (ethyleneimine), alicyclic (cyclohexylamine), disubstituted cycloalkane diamines (l,2-diaminocyclo hexane) and aromatic diamines (ophenylenediamine), as well as 2-substi-tuted (amino and aminomethyl) pyridines and analogues [9]. 

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