https://www.selleckchem.com/products/unc-3230.html The multiconfiguration time-dependent Hartree (MCTDH) method and its generalization, the multilayer MCTDH (ML-MCTDH), result in equations of motion (EOMs) that are singular when there are virtual orbitals-the unoccupied single-particle functions-in the wave function expansion. For decades this singularity had been numerically removed by regularizing the reduced density matrix. In this Perspective we discuss our recent proposal to regularize the coefficient tensor instead, which has significant impact on both the efficiency and correctness of the EOMs in MCTDH and ML-MCTDH for challenging problems. We further demonstrate that when the system becomes large such that it is necessary to use ML-MCTDH with many layers, it is much more important to employ this new regularization scheme. We illustrate this point by studying a spin-boson model with a large bath that contains up to 100 000 modes. We show that even in the weak coupling regime the new regularization scheme is required to quickly rotate the virtual orbitals into the correct directions in Hilbert space. We argue that this situation can be common for applying a time-dependent tensor network approach to any large enough system.The multistep synthesis of a novel ADP-7-azido-7-deoxy-l-glycero-β-d-manno-heptopyranoside 2a and several analogues as heptosyltransferase ligands is described. The synthesis of the key intermediate heptoside-1-β-phosphate 3a involved a β-stereoselective phosphorylation of lactol 4 employing diallyl chlorophosphate as a phosphorylating reagent. Five deprotected nucleotide sugars were generated by this synthetic sequence and evaluated as heptosyltransferase substrates (KM, kcat).Activation of anthrone via benzylic deprotonation in the presence of triethylamine paves the way for the 1,2-addition reaction with imines to provide the desired functionalized anthrones in good to excellent yields under mild and operationally simple reaction condition