Rates of N-methylation of N-methylpyrazole, isothiazole and isoxazole and their 2,1- and 1,2-benzologues

1974 ◽  
Vol 27 (6) ◽  
pp. 1221 ◽  
Author(s):  
M Davis ◽  
LW Deady ◽  
E Homfeld
Keyword(s):  
Methyl Iodide ◽  
Dimethyl Sulphate ◽  
Dimethyl Sulphoxide ◽  
New Compounds

The rates of quaternization of N-methylpyrazole, isothiazole and isoxazole and of their 2,l- and 1,2-benzologues with methyl iodide in dimethyl sulphoxide and with dimethyl sulphate are reported. All compounds quaternized at 33� and a number of new compounds were isolated. The order of reactivity in each series is NMe > S > O. Benzofusion was shown to be rate-diminishing with one exception. 2,l-Benzisoxazole reacted faster than did isoxazole and the reason for this behaviour is discussed.

Rates of N-methylation of azoles with methyl iodide and dimethyl sulphate

1973 ◽  
Vol 26 (9) ◽  
pp. 1949 ◽  
Author(s):  
LW Deady
Keyword(s):  
Methyl Iodide ◽  
Dimethyl Sulphate ◽  
Inductive Effect ◽  
Reaction Rates ◽  
Dimethyl Sulphoxide ◽  
The Other

The rates of quaternization of various azoles and their benzo derivatives with dimethyl sulphate, and with methyl iodide in dimethyl sulphoxide, are reported. Reaction rates are controlled mainly by the inductive effect of the other hetero atom and there is a good correlation between rate of quaternization and basicity of the azole.

THE REACTION OF ALKYL IODIDES WITH IODO-ARSINES IN THE PRESENCE OF MERCURY

1961 ◽  
Vol 39 (3) ◽  
pp. 420-424 ◽  
Author(s):  
M. M. Baig ◽  
W. R. Cullen
Keyword(s):  
Methyl Iodide ◽  
Ethyl Iodide ◽  
Compound C ◽  
Alkyl Iodides ◽  
New Compounds ◽  
Derivatives Of

The reaction of alkyl iodides with iodo-arsines in the presence of mercury generally gives arsonium derivatives of triiodomercury (II). Thus tetramethylarsonium triiodomercury (II) is obtained from the reactions of methyl iodide with the compounds (CH3)3−nAsIn (n = 1,2,3). Phenyl-iodo-arsines give the new compounds C6H5AsR3HgI3 and (C6H5)2AsR2HgI3 (R = CH3 or C2H5) from similar reactions. However, the reaction of iododimethylarsine with ethyl iodide gives the 1:1 arsine complex (CH3)2AsC2H5.HgI2. The compounds (C2H5)4AsI and (C2H5)4 AsHgI3 were reinvestigated, and used to prepare the compound ((C2H5)4As)2HgI4.

Crystal chemistry of high-Tc superconductors

1990 ◽  
Vol 48 (4) ◽  
pp. 1118-1119
Author(s):  
Maryvonne Hervieu
Keyword(s):  
Oxygen Deficiency ◽  
Large Family ◽  
Copper Oxides ◽  
High Tc Superconductors ◽  
High Tc ◽  
Single Mechanism ◽  
Square Planar ◽  
History Of ◽  
Bismuth Cuprates ◽  
New Compounds

Four years after the discovery of superconductivity at high temperature in the Ba-La-Cu-O system, more than thirty new compounds have been synthesized, which can be classified in six series of copper oxides: La2CuO4 - type oxides, bismuth cuprates, YBa2Cu3O7 family, thallium cuprates, lead cuprates and Nd2CuO4 - type oxides. Despite their quite different specific natures, close relationships allow their structures to be simply described through a single mechanism. The fifth first families can indeed be described as intergrowths of multiple oxygen deficient perovskite slabs with multiple rock salt-type slabs, according to the representation [ACuO3-x]m [AO]n.The n and m values are integer in the parent structures, n varying from 0 to 3 and m from 1 to 4; every member of this large family can thus be symbolized by [m,n]. The oxygen deficient character of the perovskite slabs involves the existence or the co-existence of several types of copper environment: octahedral, pyramidal and square planar.Both mechanisms, oxygen deficiency and intergrowth, are well known to give rise easily to nonstoichiometry phenomena. Numerous and various phenomena have actually been characterized in these cuprates, strongly depending on the thermal history of the samples.

Evaluation of New Compounds for Opioid Activity: Annual Report (1993)

1994 ◽  
Author(s):  
J. C. Woods ◽  
◽  
C. P. France ◽  
F. Medzihradsky ◽  
C. B. Smith ◽  
...  
Keyword(s):  
Annual Report ◽  
Opioid Activity ◽  
New Compounds

A common mechanism links activities of butyrate in the colon

2017 ◽  
Author(s):  
Mohit S. Verma ◽  
Michael J. Fink ◽  
Gabriel L Salmon ◽  
Nadine Fornelos ◽  
Takahiro E. Ohara ◽  
...  
Keyword(s):  
Stem Cells ◽  
Histone Deacetylases ◽  
Biological Activities ◽  
Short Chain Fatty Acids ◽  
Common Mechanism ◽  
Epithelial Stem Cells ◽  
Degree Of Unsaturation ◽  
Structure Activity ◽  
Starting Point ◽  
New Compounds

Two biological activities of butyrate in the colon (suppression of proliferation of colonic epithelial stem cells and inflammation) correlate with inhibition of histone deacetylases. Cellular and biochemical studies of molecules similar in structure to butyrate, but different in molecular details (functional groups, chain-length, deuteration, oxidation level, fluorination, or degree of unsaturation) demonstrated that these activities were sensitive to molecular structure, and were compatible with the hypothesis that butyrate acts by binding to the Zn<sup>2+</sup> in the catalytic site of histone deacetylases. Structure-activity relationships drawn from a set of 36 compounds offer a starting point for the design of new compounds targeting the inhibition of histone deacetylases. The observation that butyrate was more potent than other short-chain fatty acids is compatible with the hypothesis that crypts evolved (at least in part), to separate stem cells at the base of crypts from butyrate produced by commensal bacteria.

Deep Reinforcement Learning for Multiparameter Optimization in de novo Drug Design

2019 ◽  
Author(s):  
Niclas Ståhl ◽  
Göran Falkman ◽  
Alexander Karlsson ◽  
Gunnar Mathiason ◽  
Jonas Boström
Keyword(s):  
Reinforcement Learning ◽  
Short Term Memory ◽  
De Novo ◽  
De Novo Drug Design ◽  
Generative Process ◽  
New Methods ◽  
Multiparameter Optimization ◽  
Long Short Term Memory ◽  
New Compounds

<p>In medicinal chemistry programs it is key to design and make compounds that are efficacious and safe. This is a long, complex and difficult multi-parameter optimization process, often including several properties with orthogonal trends. New methods for the automated design of compounds against profiles of multiple properties are thus of great value. Here we present a fragment-based reinforcement learning approach based on an actor-critic model, for the generation of novel molecules with optimal properties. The actor and the critic are both modelled with bidirectional long short-term memory (LSTM) networks. The AI method learns how to generate new compounds with desired properties by starting from an initial set of lead molecules and then improve these by replacing some of their fragments. A balanced binary tree based on the similarity of fragments is used in the generative process to bias the output towards structurally similar molecules. The method is demonstrated by a case study showing that 93% of the generated molecules are chemically valid, and a third satisfy the targeted objectives, while there were none in the initial set.</p>

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