for the following products
(+)-N,N,N',N'-Tetramethyl-L-tartaric acid diamide | (+)-N,N,N,N-Tetramethyl-L-tartaramide | (2R,3R)-2,3-dihydroxy-N1,N1,N4,N4-tetramethylsuccinamide | (R,R)-(+)-2,3-Dihydroxy-N,N,N',N'-tetramethylsuccinamide | N,N,N',N'-Tetramethyltartramide and N,N,N',N'-Tetramethyl-L-tartramide
