NOVELTY - Preparing (3R,4R)-(1-benzyl-4-methylpiperidin-3-yl)-methylamine (IIa) comprises: (a1) N-acylating 3-amino-4-methyl pyridine (III); (a2) quartenizing nitrogen of pyridine system of resultant product of step (a1); (a3) partially reducing resultant product of step (a2); (a4) hydrolyzing 1,2,5,6-tetrahydropyridine system of resultant product of step (a3) to prepare substituted 4-methyl-3-oxo-piperidin-1-ylmethyl compounds (VIIa); (a5) carrying out reductive amination of (VIIa) to prepare (1-benzyl-4-methylpiperidin-3-yl)-methylamine (VIIIa); and (a6) carrying out further resolution of (VIIIa).    USE - The process is useful for preparing (3R,4R)-(1-benzyl-4-methylpiperidin-3-yl)-methylamine (IIa) (claimed) which is useful as an intermediate for preparing 3-((3R,4R)-4-methyl-3-(methyl(7H-pyrrolo(2,3-d)pyrimidin-4-yl)amino)piperidin-1-yl)-3-oxo-propanenitrile, 2-hydroxypropane-1,2,3-tricarboxylate that is useful for treating rheumatoid arthritis.    ADVANTAGE - The process: is cost-effective, environment friendly and energy economic process; and prepares (IIa) at a better overall yield.    DETAILED DESCRIPTION - Preparing (3R,4R)-(1-benzyl-4-methylpiperidin-3-yl)-methylamine of formula (IIa) comprises: (a1) N-acylating 3-amino-4-methyl pyridine of formula (III) with alkyl, aryl or substituted aryl acid chloride or acid anhydride to prepare substituted 4-methyl-pyridin-3-ylcarbamoyl compounds of formula (IVa) and optionally isolating (IVa); (a2) quartenizing nitrogen of pyridine system in (IVa), using benzyl or substituted aryl benzyl halide in an organic solvent to prepare substituted 3-formylamino-1,4-dimethyl-pyridinium compounds of formula (Va) and optionally isolating (Va); (a3) partially reducing (Va) to produce 1,2,5,6-tetrahydropyridine system of substituted N-(1,4-dimethyl-1,2,5,6-tetrahydro-pyridin-3-yl)-formamide compounds of formula (VIa) in presence of a reducing agent or any alkali metal borohydride agent in a solvent, at an ambient temperature; (a4) hydrolyzing 1,2,5,6-tetrahydropyridine system of (VIa) in presence of an acid or mixture of acids to prepare substituted 4-methyl-3-oxo-piperidin-1-ylmethyl compounds of formula (VIIa) at an ambient temperature; (a5) carrying out reductive amination of (VIIa) using methylamine in presence of any Lewis acids in an organic solvent and/or an aqueous solvent followed by reduction using any reducing agent or any alkali metal borohydride derivatives to prepare (1-benzyl-4-methylpiperidin-3-yl)-methylamine of formula (VIIIa) at an ambient temperature; and (a6) carrying out further resolution of (VIIIa) in presence of any resoluting agent in an organic solvent and/or an aqueous solvent to prepare (IIa).    R1 = aryl (optionally substituted) or alkyl, preferably methyl;    R2 = aryl (optionally substituted) or 3-10C alkyl, where R2 is not isopropyl or phenyl;    R11 = aryl (optionally substituted), preferably phenyl; and    X1- = halide e.g. Cl-, Br-, I-, or any leaving group e.g. tosyloxy or mesyloxy.    INDEPENDENT CLAIMS are also included for:    (1) substituted 4-methyl-pyridin-3-ylcarbamoyl compounds (IVa) or their salts;    (2) substituted 3-formylamino-1,4-dimethyl-pyridinium compounds (Va) or their salts; and    (3) substituted N-(1,4-dimethyl-1,2,5,6-tetrahydro-pyridin-3-yl)-formamide compounds (VIa) or their salts.