Day: January 6, 2023

Metallotropic transitions in organomercury derivatives of pyrazoles studied by the NMR method was written by Kravtsov, D. N.;Fedorov, L. A.;Peregudov, A. S.;Nesmeyanov, A. N.. And the article was included in Doklady Akademii Nauk SSSR in 1971.Recommanded Product: 15953-73-8 This article mentions the following:

The PMR spectra of 3,5-dimethyl-4-X-substituted-pyrazoles, in which X was selected from Cl, Br, or NO2, and their N-(phenylmercurio) derivatives, were obtained in CH2Cl2-CHCl3 solution with or without added C5H5N or CD3NO2. The signals from the Me protons in the -110° to room temperature range are tabulated. The cationotropic phenomena in this group of compounds are explained by using the spectral data. The PhHg group (or H) migration between the N atoms was little affected by addition of CD3NO2 and the small amount of acceleration showed that the rearrangement is probably intramol. with a transition state in which Hg is coordinated with both N atoms. Addition of C5H5N to the system greatly accelerated the rearrangement among the PhHg derivatives The following N-phenylmercurio-3,5-dimethylpyrazoles were prepared conventionally (X and m.p. given): Cl, 143-4°; Br, 39-40°; NO2, 184-5°. 1,2-Dimethyl-4,5-dichloroimidazole, m. 49-50°, was prepared from 2-methyl-4,5-dichloroimidazole and Me2SO4 in alk. medium. In the experiment, the researchers used many compounds, for example, 4-Chloro-3,5-dimethyl-1H-pyrazole (cas: 15953-73-8Recommanded Product: 15953-73-8).

4-Chloro-3,5-dimethyl-1H-pyrazole (cas: 15953-73-8) belongs to pyrazole derivatives. Pyrazole and its derivatives are considered a pharmacologically important active scaffold that possesses almost all types of pharmacological activities. The pyrazole ring is resistant to oxidation and reduction but the groups, such as alkyl and formyl attached to the ring, are oxidized to respective acids. Only electrolytic oxidation, ozonolysis, and a strong base cause ring opening.Recommanded Product: 15953-73-8

Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

t-Butyl as a pyrazole protecting group: preparation and use of 1-tert-butyl-3-methyl-1H-pyrazol-5-amine was written by Pollock, Patrick M.;Cole, Kevin P.. And the article was included in Organic Syntheses in 2012.Name: 1-(tert-Butyl)-3-methyl-1H-pyrazol-5-amine This article mentions the following:

Pyrazole I was prepared in one step from the cyclocondensation reaction of t-butylhydrazine hydrochloride with 3-aminocrotononitrile. Application of I in the preparation N-(5-methyl-1H-pyrazol-3-yl)-2-pyridinamine was demonstrated. In the experiment, the researchers used many compounds, for example, 1-(tert-Butyl)-3-methyl-1H-pyrazol-5-amine (cas: 141459-53-2Name: 1-(tert-Butyl)-3-methyl-1H-pyrazol-5-amine).

1-(tert-Butyl)-3-methyl-1H-pyrazol-5-amine (cas: 141459-53-2) belongs to pyrazole derivatives. Pyrazole has two ring nitrogen atoms in which N1 is pyrrolic and N2 is pyridine-like. The N1 nitrogen is not reactive but is deprotonated in the presence of a base-forming anion. Pyrazole rings have been used as core components of several leading non-steroidal anti-inflammatory drugs (NSAIDs) and antihypertensive drugs. It has also been found to be useful as a bifunctional ligand for metal catalysis.Name: 1-(tert-Butyl)-3-methyl-1H-pyrazol-5-amine

Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

The Empirical Correlation between Hydrogen Bonding Strength and Excited-State Intramolecular Proton Transfer in 2-Pyridyl Pyrazoles was written by Lin, Tsung-Yi;Tang, Kuo-Chun;Yang, Shen-Han;Shen, Jiun-Yi;Cheng, Yi-Ming;Pan, Hsiao-An;Chi, Yun;Chou, Pi-Tai. And the article was included in Journal of Physical Chemistry A in 2012.Recommanded Product: 19959-77-4 This article mentions the following:

A series of 2-pyridyl pyrazoles with various functional groups attached to either pyrazole or pyridyl moieties have been strategically designed and synthesized in an aim to probe the hydrogen bonding strength in the ground state vs. dynamics of excited-state intramol. proton transfer (ESIPT) reaction. The title compounds all possess a five-membered-ring (pyrazole)N-H···N(pyridine) intramol. hydrogen bond, in which both the N-H bond and the electron d. distribution of the pyridyl nitrogen lone-pair electrons are rather directional, so that the hydrogen bonding strength is relatively weak, which is sensitive to the perturbation of subtle chem. substitution and consequently reflected from the associated ESIPT dynamics. Various approaches such as ¹H NMR (N-H proton) to probe the hydrogen bonding strength and absorption titration to assess the acidity-basicity property were made for all the title analogs. The results, together with supplementary support provided by a computational approach, affirm that the increase of acidity (basicity) on the hydrogen bonding donor (acceptor) sites leads to an increase of hydrogen-bonding strength among the title 2-pyridyl pyrazoles. Luminescence results and the associated ESIPT dynamics further reveal an empirical correlation in that the increase of the hydrogen bonding strength leads to an increase of the rate of ESIPT for the title 2-pyridyl pyrazoles, demonstrating an interesting relationship among N-H acidity, hydrogen bonding strength, and the associated ESIPT rate. In the experiment, the researchers used many compounds, for example, 2-(5-Methyl-1H-pyrazol-3-yl)pyridine (cas: 19959-77-4Recommanded Product: 19959-77-4).

2-(5-Methyl-1H-pyrazol-3-yl)pyridine (cas: 19959-77-4) belongs to pyrazole derivatives. Pyrazole and its derivatives are considered a pharmacologically important active scaffold that possesses almost all types of pharmacological activities. Pyrazoles are commonly used scaffold molecules in drug discovery projects. The use of pyrazole derivatives is based on their analgesic, anti-inflammatory, antipyretic, antiarrhythmic, sedative, muscle relaxant, neuroleptic, anticonvulsant, monoamine oxidase inhibitory, antidiabetic and antibacterial activities.Recommanded Product: 19959-77-4

Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

Site-Selective C-H Functionalization of (Hetero)Arenes via Transient, Non-symmetric Iodanes was written by Fosu, Stacy C.;Hambira, Chido M.;Chen, Andrew D.;Fuchs, James R.;Nagib, David A.. And the article was included in Chem in 2019.COA of Formula: C5H7ClN2 This article mentions the following:

A strategy for C-H functionalization of arenes and heteroarenes has been developed to allow site-selective incorporation of various anions, including Cl, Br, OMs, OTs, and OTf. This approach is enabled by in situ generation of reactive, non-sym. iodanes by combining anions and bench-stable PhI(OAc)₂. The utility of this mechanism is demonstrated via para-selective chlorination of medicinally relevant arenes, as well as site-selective C-H chlorination of heteroarenes. Spectroscopic, computational, and competition experiments describe the unique nature, reactivity, and selectivity of these transient, unsym. iodanes. In the experiment, the researchers used many compounds, for example, 4-Chloro-3,5-dimethyl-1H-pyrazole (cas: 15953-73-8COA of Formula: C5H7ClN2).

4-Chloro-3,5-dimethyl-1H-pyrazole (cas: 15953-73-8) belongs to pyrazole derivatives. Pyrazole is a weak base, with pKb 11.5 (pKa of the conjugated acid 2.49 at 25 °C).Pyrazole used as a ligand to prepare organometallic compounds. Pyrazoles can be selectively lithiated at different carbons and subsequently react with electrophiles depending on the substitution patterns.COA of Formula: C5H7ClN2

Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

The N-alkylation and N-arylation of unsymmetrical pyrazoles was written by Grimmett, M. Ross;Lim, K. H. Richard;Weavers, Rex T.. And the article was included in Australian Journal of Chemistry in 1979.Name: 3-(4-Bromophenyl)-1H-pyrazole This article mentions the following:

Unsym. pyrazoles with alkyl, aryl, nitro and carboxyl substituents at C-3 or C-5 were methylated with Me₂SO₄-MeOH, Me₂SO₂ in basic medium, and with CH₂N₂. The ratios of the isomeric N-methylpyrazoles were determined by NMR and gas liquid chromatog. The modified Ullmann phenylation was also applied to these pyrazoles. Product orientations involve considerations of electronic and steric effects, the possible intermediacy of quaternary salts, and the likelihood that the dominant tautomer is reacting. In the experiment, the researchers used many compounds, for example, 3-(4-Bromophenyl)-1H-pyrazole (cas: 73387-46-9Name: 3-(4-Bromophenyl)-1H-pyrazole).

3-(4-Bromophenyl)-1H-pyrazole (cas: 73387-46-9) belongs to pyrazole derivatives. Pyrazole has two ring nitrogen atoms in which N1 is pyrrolic and N2 is pyridine-like. The N1 nitrogen is not reactive but is deprotonated in the presence of a base-forming anion. Pyrazoles are commonly used scaffold molecules in drug discovery projects. The use of pyrazole derivatives is based on their analgesic, anti-inflammatory, antipyretic, antiarrhythmic, sedative, muscle relaxant, neuroleptic, anticonvulsant, monoamine oxidase inhibitory, antidiabetic and antibacterial activities.Name: 3-(4-Bromophenyl)-1H-pyrazole

Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

Effects of hydrogen bond on the melting point of azole explosives was written by Wang, Jian-Hua;Shen, Chen;Liu, Yu-Cun;Luo, Jin;Duan, Yingjie. And the article was included in Journal of Molecular Structure in 2018.Safety of 3-Methyl-4-nitro-1H-pyrazole This article mentions the following:

M.p. is an important index to determine whether an explosive can be a melt cast carrier. In this study, the relationship among the mol. structure, crystal structure, and m.p. of explosives was investigated by using nitroazole compounds Hydrogen bonds influence crystal packing modes in chem. understandable ways. Hydrogen bonds also affect the changes in entropy and enthalpy in balancing melting process. Hence, different types of hydrogen bonds in explosive crystal structures were compared when the relationship between the mol. structure and the m.p. of nitroazole explosives were analyzed. The effects of Me and amino groups on intermol. hydrogen bonds were also compared. Results revealed that the Me and amino groups connected on the N(1) of the heterocyclic compound can reduce the m.p. of azole explosive. This finding is possible because Me and amino groups destroy the intermol. hydrogen bond of the heterocyclic compound In the experiment, the researchers used many compounds, for example, 3-Methyl-4-nitro-1H-pyrazole (cas: 5334-39-4Safety of 3-Methyl-4-nitro-1H-pyrazole).

3-Methyl-4-nitro-1H-pyrazole (cas: 5334-39-4) belongs to pyrazole derivatives. The strategies for the synthesis of pyrazoles generally can be applied for the construction of indazoles. Pyrazoles can be selectively lithiated at different carbons and subsequently react with electrophiles depending on the substitution patterns.Safety of 3-Methyl-4-nitro-1H-pyrazole

Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

From N-H Nitration to Controllable Aromatic Mononitration and Dinitration-The Discovery of a Versatile and Powerful N-Nitropyrazole Nitrating Reagent was written by Yang, Tao;Li, Xiaoqian;Deng, Shuang;Qi, Xiaotian;Cong, Hengjiang;Cheng, Hong-Gang;Shi, Liangwei;Zhou, Qianghui;Zhuang, Lin. And the article was included in JACS Au in 2022.Formula: C4H5N3O2 This article mentions the following:

Herein,the identification of a powerful nitrating reagent, 5-methyl-1,3-dinitro-1H-pyrazole, from the N-nitro-type reagent library constructed using a practical N-H nitration method was reported. This nitrating reagent behaved as a controllable source of the nitronium ion, enabling mild and scalable nitration of a broad range of (hetero)arenes with good functional group tolerance. Of note, this nitration method was controlled by manipulating the reaction conditions to furnish mononitrated or dinitrated product selectively. The value of this method in medicinal chem. was well established by its efficient late-stage C-H nitration of complex biorelevant mols. D. functional theory (DFT) calculations and preliminary mechanistic studies reveal that the powerfulness and versatility of this nitrating reagent were due to the synergistic “nitro effect” and “methyl effect”. In the experiment, the researchers used many compounds, for example, 3-Methyl-4-nitro-1H-pyrazole (cas: 5334-39-4Formula: C4H5N3O2).

3-Methyl-4-nitro-1H-pyrazole (cas: 5334-39-4) belongs to pyrazole derivatives. The 1H-pyrazole provides an excellent means by which to provide the requisite hydrogen bond acceptor–donor motifs, whether as a monocyclic ring or as a fused indazole ring. The pyrazole ring is resistant to oxidation and reduction but the groups, such as alkyl and formyl attached to the ring, are oxidized to respective acids. Only electrolytic oxidation, ozonolysis, and a strong base cause ring opening.Formula: C4H5N3O2

Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

Experimental Testing of Quantum Mechanical Predictions of Mutagenicity: Aminopyrazoles was written by Leach, Andrew G.;McCoull, William;Bailey, Andrew;Barton, Peter;Mee, Christine;Rosevere, Eleanor. And the article was included in Chemical Research in Toxicology in 2013.Name: 1-Ethyl-1H-pyrazol-3-amine This article mentions the following:

A computational method for predicting the likelihood of aromatic amines being active in the Ames test for mutagenicity was trialed on a set of aminopyrazoles. A virtual array of compounds was generated from the available sets of hydrazines and α-cyanoaldehydes (or ketones) and quantum mech. calculations used to compute a probability of being active in the Ames test. The compounds selected for synthesis and testing were not based on the predictions and so spanned the range of predicted probabilities. The subsequently generated results of the Ames test were in good correspondence with the predictions and confirm this approach as a useful means of predicting likely mutagenic risk. In the experiment, the researchers used many compounds, for example, 1-Ethyl-1H-pyrazol-3-amine (cas: 55361-49-4Name: 1-Ethyl-1H-pyrazol-3-amine).

1-Ethyl-1H-pyrazol-3-amine (cas: 55361-49-4) belongs to pyrazole derivatives. Pyrazole is a weak base, with pKb 11.5 (pKa of the conjugated acid 2.49 at 25 °C).Pyrazole used as a ligand to prepare organometallic compounds. Pyrazole rings have been used as core components of several leading non-steroidal anti-inflammatory drugs (NSAIDs) and antihypertensive drugs. It has also been found to be useful as a bifunctional ligand for metal catalysis.Name: 1-Ethyl-1H-pyrazol-3-amine

Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

κ²-κ³ Isomerism in Rhodium(I) Tris(pyrazolyl)borate Complexes of the Type Tp^3R,4R,5RRh(LL) (LL = 2CO, COD, and NBD) and Their Dynamic Behavior in Solution. X-ray Crystal Structure of Tp^MeRh(NBD) was written by Bucher, Urs E.;Currao, Antonio;Nesper, Reinhard;Rueegger, Heinz;Venanzi, Luigi M.;Younger, Elizabeth. And the article was included in Inorganic Chemistry in 1995.Related Products of 15953-73-8 This article mentions the following:

Rh(I) complexes Tp^3R,4R,5RRh(LL) (LL = 2 CO, NBD (norbornadiene), COD (1,5-cyclooctadiene), 3R = 4R = 5R = H; 3R = Me, 4R = 5R = H; 3R = Me, Ph, CF₃, 4R = H, 5R = Me; 3R = Me, 4R = Me, Cl, 5R = Me; 3R = ⁱPr, 4R = Br, 5R = H) were synthesized and fully characterized. Isomeric forms of three types were identified in solution for these compounds: type A, square planar complexes in which the Rh(NN)₂B six-membered ring has a boat conformation, the 3rd pyrazolyl ring being free and occupying an equatorial position; type B, compounds with a coordination geometry and chelate ring as above, but having the 3rd pyrazolyl ring in an axial position, i.e., an arrangement which can easily form pentacoordinate complexes; type C, five-coordinate species which, however, on the NMR time scale, are in a fast exchange with those B. In the carbonyl complexes (LL = 2 CO), compounds C can be distinguished from the forms A and B by IR spectroscopy. The dynamic equilibrium between the corresponding isomeric structures, A, B, and C, are solvent-dependent and can be shifted completely toward the forms B and C by placing a Me substituent in the 5-position of each pyrazole. For compounds possessing COD as a co-ligand, the formation of square-planar complexes B, with κ²-bonded pyrazolylborates is preferred, as indicated by ¹⁰³Rh NMR spectroscopy, whereas both four- and five-coordinate species are present in compounds having NBD as a co-ligand, their relative contributions being dependent on the substituents on the pyrazolyl rings. The x-ray crystal structure of the compound Tp^MeRh(NBD) (space group P2₁/c, a 18.152(3), b 16.732(4), c 20.591(4) Å; β = 141.793(7); Z = 8; R = 0.0457, R_w = 0.0412 for 3904 observed reflections) shows that the tris(pyrazolyl)borate ligand is κ³-bonded and the Rh atom has a distorted trigonal bipyramidal structure (type C), the two olefinic double bonds being in an equatorial and the an axial position, resp. In the experiment, the researchers used many compounds, for example, 4-Chloro-3,5-dimethyl-1H-pyrazole (cas: 15953-73-8Related Products of 15953-73-8).

4-Chloro-3,5-dimethyl-1H-pyrazole (cas: 15953-73-8) belongs to pyrazole derivatives. Pyrazole and its derivatives are considered a pharmacologically important active scaffold that possesses almost all types of pharmacological activities. Pyrazoles can be selectively lithiated at different carbons and subsequently react with electrophiles depending on the substitution patterns.Related Products of 15953-73-8

Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics

Screening of volatile organic pollutants in water of Almaty lake-settler by SPME-GC-MS was written by Alimzhanova, M. B.. And the article was included in Izvestiya Natsional’noi Akademii Nauk Respubliki Kazakhstan, Seriya Khimii i Tekhnologii in 2016.Quality Control of 3-Methyl-4-nitro-1H-pyrazole This article mentions the following:

Environmental problems of big cities are directly related to the high concentration of population, industry and transport in small areas, which are the cause of a large number of industrial and domestic emissions. These emissions may represent a different kind of chem. compounds: volatile,semi-volatile and toxic organic compounds, which can be merged with water and pollute it. As a result there are several so-called lake-settlers, where contaminated water is stored for further purification An annual monitoring of these lakes it is necessary carry out for to prevent the possibility of getting these compounds in drinking water and harm to the environment. The Environmental Protection Agency offered EPA 8270S method for determination volatile and semi-volatile compounds in the environmental objects by GC-MS. However, this technique is not economically profitable,since it requires the use of expensive reference materials for calibration curve and set retention times of all 210 compounds and organic solvents for extraction The aim of this work is to develop a new selective, informative and efficient green method for the detection of VOCs in water without using organic solvents for extraction and without require of use expensive standard samples. Method of solid phase microextraction and GC/MS with identification of peaks by Kovatc’s indexes is the most appropriate responding to all requests for the detection of VOCs in the environment. The green method will enable to determine VOCs in environmental objects. Results of work included the optimization of SPME parameters and calculation of retention times of n-alkanes. Using the retention times and retention indexes of n-alkanes the dependence was built, which allowed to calculate the retention times of 210 organic pollutants. Also this method was successfully applied for anal. of water from Almaty Lake-Settler “Sorbulak” and 68 main organic compounds were identified, including phenolic compounds,pesticides and polyaromatic hydrocarbons. In the experiment, the researchers used many compounds, for example, 3-Methyl-4-nitro-1H-pyrazole (cas: 5334-39-4Quality Control of 3-Methyl-4-nitro-1H-pyrazole).

3-Methyl-4-nitro-1H-pyrazole (cas: 5334-39-4) belongs to pyrazole derivatives. Pyrazole and its derivatives are considered a pharmacologically important active scaffold that possesses almost all types of pharmacological activities. The pyrazole ring is resistant to oxidation and reduction but the groups, such as alkyl and formyl attached to the ring, are oxidized to respective acids. Only electrolytic oxidation, ozonolysis, and a strong base cause ring opening.Quality Control of 3-Methyl-4-nitro-1H-pyrazole

Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics