Reduction of 2-, 3- and 4-methylquinolines, 2-, 3- and 4-quinolylmethanols and corresponding quinolinecarboxaldehydes with triethylammonium formate

Abstract

Reduction of the compounds mentioned in the title with triethylammonium formate gave 1-formyl-C-methyl-1,2,3,4-tetrahydroquinolines IIa-IIc. On reduction of derivatives substituted in the position 3 and 4 (Ib, Ic, Ie, If, Ih, Ii) the products of 1,2-addition are also formed i.e. IIIa, IIIb, and on reduction of 3-quinolylmethanol (Ie) and 3-quinolinecarboxaldehyde (Ih) the products of 1,4-addition, i.e. IVa, IVb also result. Alcohol If and aldehyde Ii also give the product of the reduction of the functional groups, i.e. 4-methylquinoline (Ic). When 3-quinolylmethanol (Ie) was prepared by reduction of aldehyde Ih with sodium borohydride 1,2,3,4-tetrahydro-3-quinolylmethanol (IIe) was also isolated.