01912nas a2200253   4500008004100000022001400041245013700055210006900192260007300261300001000334490000800344520099500352653001201347653002301359653001601382653000601398653001701404653002301421653001601444100002201460700001801482700002901500856012901529       2005                        eng d  a1381-116900aSelective synthesis of N,N-dimethyl aniline derivatives using dimethyl carbonate as a methylating agent and onium salt as a catalyst0 aSelective synthesis of NNdimethyl aniline derivatives using dime  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcFEB  a49-560 v2263 a<p>N-Alkylation of anilines by dimethyl carbonate (DMC) catalyzed by onium salts has been demonstrated. The work presented here shows that a simple catalytic system consisting of onium salts in the presence of a small amount of water is extremely effective in enhancing the DMC mediated N-alkylation of anilines to dialkylated products. The effect of reaction conditions on the synthesis of N,N-dimethyl aniline (NNDMA) from aniline and DMC has been investigated. Under the optimized conditions highest yield of NNDMA obtained was 99.8%, which is the best reported for liquid phase N-alkylation of aniline using DMC. The role of water in enhancing the yield of NNDMA is explained and a reaction-networking scheme is constructed, which summarizes the chemistry behind liquid phase N-alkylation of anilines by DMC. The catalyst has been shown to recycle up to five times and at the end of fifth recycle almost 98% of NNDMA yields were obtained. (C) 2004 Elsevier B.V. All rights reserved.</p>10aAniline10aDimethyl carbonate10amethylation10aN10aN-alkylation10aN-dimethyl aniline10aonium salts1 aShivarkar, A., B.1 aGupte, S., P.1 aChaudhari, Raghunath, V.  uhttp://library.ncl.res.in/content/selective-synthesis-nn-dimethyl-aniline-derivatives-using-dimethyl-carbonate-methylating-002403nas a2200217   4500008004100000245009700041210006900138260000900207300000700216490000700223520165600230653001601886653001601902653001601918653002301934653003701957653000801994100002802002700003602030856011902066       2021                        eng d00aMethylation as a key regulator of Tau aggregation and neuronal health in Alzheimer's disease0 aMethylation as a key regulator of Tau aggregation and neuronal h  cMAY   a510 v193 a<p>Neurodegenerative diseases like Alzheimer's, Parkinson's and Huntington's disease involves abnormal aggregation and accumulation of toxic proteins aggregates. Post-translational modifications (PTMs) of the causative proteins play an important role in the etiology of disease as they could either slow down or accelerate the disease progression. Alzheimer disease is associated with the aggregation and accumulation of two major protein aggregates-intracellular neurofibrillary tangles made up of microtubule-associated protein Tau and extracellular Amyloid-beta plaques. Post-translational modifications are important for the regulation of Tau`s function but an imbalance in PTMs may lead to abnormal Tau function and aggregation. Tau methylation is one of the important PTM of Tau in its physiological state. However, the methylation signature on Tau lysine changes once it acquires pathological aggregated form. Tau methylation can compete with other PTMs such as acetylation and ubiquitination. The state of PTM at these sites determines the fate of Tau protein in terms of its function and stability. The global methylation in neurons, microglia and astrocytes are involved in multiple cellular functions involving their role in epigenetic regulation of gene expression via DNA methylation. Here, we have discussed the effect of methylation on Tau function in a site-specific manner and their cross-talk with other lysine modifications. We have also elaborated the role of methylation in epigenetic aspects and neurodegenerative conditions associated with the imbalance in methylation metabolism affecting global methylation state of cells.</p>10aAggregation10aEpigenetics10amethylation10aMethyltransferases10apost-translational modifications10aTau1 aBalmik, Abhishek, Ankur1 aChinnathambi, Subashchandrabose  uhttp://library.ncl.res.in/content/methylation-key-regulator-tau-aggregation-and-neuronal-health-alzheimers-disease