Transformation of tertiary amines into alkylating reagents by treatment with 2-chloro-4,6-dimethoxy-1,3,5-triazine. A synthetic application of side-reaction accompanying coupling by means of 4-(4,6-dimethoxy-[1,3,5] triazin-2-yl)-4-methyl-morpholin-4-ium chloride (DMTMM)