Tag: 200-300

Rh-Catalyzed Asymmetric Hydrogenation of α,β- and β,β-Disubstituted Unsaturated Boronate Esters was written by Yan, Qiaozhi;Shen, Xin;Zi, Guofu;Hou, Guohua. And the article was included in Chemistry – A European Journal in 2020.Recommanded Product: 653-92-9 This article mentions the following:

Chiral phenethyl boronates ArCHRCH₂Bpin and ArCH₂CHRBpin were prepared by asym. hydrogenation of α- and β-substituted β-styrylboronates. A highly enantioselective hydrogenation of α,β-unsaturated boronate esters catalyzed by Rh-(S)-DTBM-Segphos complex has been developed. Both (Z)-α,β- and β,β-disubstituted substrates can be successfully hydrogenated to afford chiral boronates with excellent enantioselectivities, up to 98% ee. Furthermore, the obtained chiral boronate esters, as important versatile synthetic intermediates are successfully transformed to the corresponding chiral alcs., amines and other important derivatives with maintained enantioselectivities. In the experiment, the researchers used many compounds, for example, Methyl 2-bromo-4-fluorobenzoate (cas: 653-92-9Recommanded Product: 653-92-9).

Methyl 2-bromo-4-fluorobenzoate (cas: 653-92-9) belongs to organobromine compounds. Bromo compounds are employed in a variety of metal-catalyzed coupling reactions. They are also ideal candidates for the synthesis of Grignard reagents that have wide-applicability in organic synthesis. alpha-Bromoesters are employed in the Reformatsky reaction for the synthesis of beta-hydroxyesters. Many of the alkyl bromine derivatives are excellent alkylating agents since bromides are good leaving groups. Tribromides, like tetrabutylammonium tribromide, are used as a solid source of bromine. N-bromosuccimide (NBS) is used for the selective bromination of allylic bonds.Recommanded Product: 653-92-9

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary

Synthesis of pyrazolo[1,5-c]quinazoline derivatives through the copper-catalyzed domino reaction of o-alkenyl aromatic isocyanides with diazo compounds was written by Liu, Lu;Li, Lei;Mao, Shukuan;Wang, Xin;Zhou, Ming-Dong;Zhao, Yu-long;Wang, He. And the article was included in Chemical Communications (Cambridge, United Kingdom) in 2020.SDS of cas: 76437-44-0 This article mentions the following:

A novel copper-catalyzed domino reaction between o-alkenyl aromatic isocyanides and diazo compounds was developed under mild reaction conditions. Various o-alkenyl aromatic isocyanides were prepared from readily available reactants. The reaction provided a general and efficient method for synthesis of pyrazolo[1,5-c]quinazolines I [R¹ = cyclohexyl, 2-thienyl, 2-naphthyl, etc.; R² = H, 8-MeO, 7-Cl, etc.; R³ = OEt, OBn, 4-ClC₆H₄, etc.] by the formation of two rings and three new bonds in a single step from readily available acyclic starting materials. A mechanism involving a tandem (3+2) cyclization/elimination/intramol. aza-addition sequence was proposed. In the experiment, the researchers used many compounds, for example, 1-(Bromomethyl)-4-fluoro-2-nitrobenzene (cas: 76437-44-0SDS of cas: 76437-44-0).

1-(Bromomethyl)-4-fluoro-2-nitrobenzene (cas: 76437-44-0) belongs to organobromine compounds. Bromine is more electronegative than carbon (2.9 vs 2.5). Consequently, the carbon in a carbon–bromine bond is electrophilic, i.e. alkyl bromides are alkylating agents. The reactivity of organobromine compounds resembles but is intermediate between the reactivity of organochlorine and organoiodine compounds. For many applications, organobromides represent a compromise of reactivity and cost.SDS of cas: 76437-44-0

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary

Selenium-Catalyzed Carbonylative Synthesis of 3,4-Dihydroquinazolin-2(1H)-one Derivatives with TFBen as the CO Source was written by Zhou, Rong;Qi, Xinxin;Wu, Xiao-Feng. And the article was included in ACS Combinatorial Science in 2019.Recommanded Product: 76437-44-0 This article mentions the following:

An efficient and general carbonylative procedure for the synthesis of 3,4-dihydroquinazolin-2(1H)-one from 1-(halomethyl)-2-nitrobenzenes and aryl/alkyl amines have been explored. In this approach, to avoid of using toxic CO gas, a solid and stable CO precursor, TFBen (benzene-1,3,5-triyl triformate), was utilized. With elemental selenium as the catalyst, a variety of aryl/alkyl amines has been tolerated well to afford the corresponding 3,4-dihydroquinazolin-2(1H)-one products in moderate to excellent yields under mild reaction condition. In the experiment, the researchers used many compounds, for example, 1-(Bromomethyl)-4-fluoro-2-nitrobenzene (cas: 76437-44-0Recommanded Product: 76437-44-0).

1-(Bromomethyl)-4-fluoro-2-nitrobenzene (cas: 76437-44-0) belongs to organobromine compounds. Most organobromine compounds, like most organohalide compounds, are relatively nonpolar. In the pharmaceutical industry organo bromine derivatives are used as sedatives, vasodilators, antiseptic agents, and anticancer agents.Recommanded Product: 76437-44-0

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary

Construction of Complex Bisether-Bridged Medium-Sized Cyclic Compounds from o-(1-(Acyloxy)propargyl)benzaldehydes under Base and Acid Catalysis was written by Zhao, Yun-Long;Cheng, Ying. And the article was included in Journal of Organic Chemistry in 2019.Reference of 85118-24-7 This article mentions the following:

The authors report herein the authors’ serendipitous discovery of the rapid and straightforward accesses to unprecedented diverse complex mol. structures from readily available starting materials. Catalyzed by 1,8-diazabicyclo[5.4.0]undec-7-ene under mild conditions, o-(1-(acyloxy)propargyl)benzaldehyde underwent efficient and selective dimerization reactions to produce novel complex bisether-bridged tricyclic products. The reactions proceeded most probably through dimerizations between 3-methylene-3H-isochromene intermediate and its zwitterionic resonance structures which were generated from a concerted 6-π electrocyclic ring closure reaction from the initially formed (2-formylphenyl)allene intermediates derived directly from o-(1-(acyloxy)propargyl)benzaldehydes. Treatment of the resulting product simply with NaOEt in ethanol and aqueous HCl, resp., enabled further development of complex mol. diversities. In the experiment, the researchers used many compounds, for example, 2-Bromo-4-(trifluoromethyl)benzaldehyde (cas: 85118-24-7Reference of 85118-24-7).

2-Bromo-4-(trifluoromethyl)benzaldehyde (cas: 85118-24-7) belongs to organobromine compounds. Most organobromine compounds, like most organohalide compounds, are relatively nonpolar. When the molecular ion is detected, the bromine and chlorine isotope patterns are very distinct, but caution is to be exercised for certain mixed chlorinated/brominated compounds, which can look similar to homohalogen patterns.Reference of 85118-24-7

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary

A transient directing group strategy enables enantioselective reductive Heck hydroarylation of alkenes was written by Oxtoby, Lucas J.;Li, Zi-Qi;Tran, Van T.;Erbay, Tugce G.;Deng, Ruohan;Liu, Peng;Engle, Keary M.. And the article was included in Angewandte Chemie, International Edition in 2020.Category: bromides-buliding-blocks This article mentions the following:

Metal-coordinating directing groups have seen extensive use in the field of transition-metal-catalyzed alkene functionalization; however, their waste-generating installation and removal steps limit the efficiency and practicality of reactions that rely on their use. Inspired by developments in asym. organocatalysis, where reactions rely on reversible covalent interactions between an organic substrate and a chiral mediator, we have developed a transient-directing-group approach to reductive Heck hydroarylation of alkenyl benzaldehyde substrates that proceeds under mild conditions. Highly stereoselective migratory insertion is facilitated by in situ formation of an imine from catalytic amounts of a com. available amino acid additive. Computational studies reveal an unusual mode of enantioinduction by the remote chiral center in the transient directing group. Metal-coordinating directing groups have seen extensive use in the field of transition-metal-mediated functionalization of alkenes; however, their waste-generating installation and removal steps limit the efficiency and practicality of reactions that rely on their use. Inspired by developments in the field of C-H activation, herein we report a transient directing group approach to reductive Heck hydroarylation of alkenyl benzaldehyde substrates that proceeds under mild conditions. Highly stereoselective migratory insertion is facilitated by in situ formation of an imine from catalytic amounts of com. available amino acid additive. Computational studies reveal an unusual mode of enantioinduction by the remote chiral center in the transient directing group. In the experiment, the researchers used many compounds, for example, 2-Bromo-4-(trifluoromethyl)benzaldehyde (cas: 85118-24-7Category: bromides-buliding-blocks).

2-Bromo-4-(trifluoromethyl)benzaldehyde (cas: 85118-24-7) belongs to organobromine compounds. A variety of minor organobromine compounds are found in nature, but none are biosynthesized or required by mammals. Organobromine compounds have fallen under increased scrutiny for their environmental impact. The principal reactions for organobromides include dehydrobromination, Grignard reactions, reductive coupling, and nucleophilic substitution.Category: bromides-buliding-blocks

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary

In silico prediction of the β-cyclodextrin complexation based on Monte Carlo method was written by Veselinovic, Aleksandar M.;Veselinovic, Jovana B.;Toropov, Andrey A.;Toropova, Alla P.;Nikolic, Goran M.. And the article was included in International Journal of Pharmaceutics (Amsterdam, Netherlands) in 2015.Related Products of 35065-86-2 This article mentions the following:

In this study QSPR models were developed to predict the complexation of structurally diverse compounds with β-cyclodextrin based on SMILES notation optimal descriptors using Monte Carlo method. The predictive potential of the applied approach was tested with three random splits into the sub-training, calibration, test and validation sets and with different statistical methods. Obtained results demonstrate that Monte Carlo method based modeling is a very promising computational method in the QSPR studies for predicting the complexation of structurally diverse compounds with β-cyclodextrin. The SMILES attributes (structural features both local and global), defined as mol. fragments, which are promoters of the increase/decrease of mol. binding constants were identified. These structural features were correlated to the complexation process and their identification helped to improve the understanding for the complexation mechanisms of the host mols. In the experiment, the researchers used many compounds, for example, 3-Bromophenyl acetate (cas: 35065-86-2Related Products of 35065-86-2).

3-Bromophenyl acetate (cas: 35065-86-2) belongs to organobromine compounds. Bromine is more electronegative than carbon (2.9 vs 2.5). Consequently, the carbon in a carbon–bromine bond is electrophilic, i.e. alkyl bromides are alkylating agents. The reactivity of organobromine compounds resembles but is intermediate between the reactivity of organochlorine and organoiodine compounds. For many applications, organobromides represent a compromise of reactivity and cost.Related Products of 35065-86-2

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary

A C-to-O atom-swapping reaction sequence enabled by Ni-catalyzed decarbonylation of lactones was written by Luu, Quang H.;Li, Junqi. And the article was included in Chemical Science in 2022.Name: 2-Bromo-4-(trifluoromethyl)benzaldehyde This article mentions the following:

Advances in site-selective functionalization reactions have enabled single atom changes on the periphery of a complex mol., but reaction manifolds that enable such changes on the core framework of the mol. remain sparse. Here, authors disclose a strategy for carbon-to-oxygen substitution in cyclic diarylmethanes and diarylketones to yield cyclic diarylethers. Oxygen atom insertion is accomplished by methylene and Baeyer-Villiger oxidations To remove the carbon atom in this C-to-O “atom swap” process, authors developed a nickel-catalyzed decarbonylation of lactones to yield the corresponding cyclic diaryl ethers. This reaction was enabled by mechanistic studies with stoichiometric nickel(II) complexes that led to the optimization of a ligand capable of promoting a challenging C(sp2)-O(aryl) reductive elimination. The nickel-catalyzed decarbonylation was applied to 6-8 membered lactones (16 examples, 32-99%). Finally, a C-to-O atom-swapping reaction sequence was accomplished on a natural product and a pharmaceutical precursor. In the experiment, the researchers used many compounds, for example, 2-Bromo-4-(trifluoromethyl)benzaldehyde (cas: 85118-24-7Name: 2-Bromo-4-(trifluoromethyl)benzaldehyde).

2-Bromo-4-(trifluoromethyl)benzaldehyde (cas: 85118-24-7) belongs to organobromine compounds. Bromo compounds are employed in a variety of metal-catalyzed coupling reactions. They are also ideal candidates for the synthesis of Grignard reagents that have wide-applicability in organic synthesis. alpha-Bromoesters are employed in the Reformatsky reaction for the synthesis of beta-hydroxyesters. Bromine-containing agents predominate because not only are they more efficient than similar chlorine-containing species, but also the high atomic weight of bromine ensures that it is present in a high mass fraction within most organobromine compounds.Name: 2-Bromo-4-(trifluoromethyl)benzaldehyde

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary

Monobromination of primary arylamines by NBS-DMF system was written by Yang, Hongqin;Cai, Junchao. And the article was included in Zhongguo Yaowu Huaxue Zazhi in 1995.SDS of cas: 615-55-4 This article mentions the following:

The reaction between equimolar N-bromosuccinimide (NBS) and some primary arylamines in dry DMF was systematically studied and it was found that NBS in DMF was ideal for the monobromination of primary arylamines. E.g., treating Et p-aminobenzoate with NBS in DMF at room temp gave 92% Et 2-bromo-4-aminobenzoate. In the experiment, the researchers used many compounds, for example, 3,4-Dibromoaniline (cas: 615-55-4SDS of cas: 615-55-4).

3,4-Dibromoaniline (cas: 615-55-4) belongs to organobromine compounds. Bromo compounds are employed in a variety of metal-catalyzed coupling reactions. They are also ideal candidates for the synthesis of Grignard reagents that have wide-applicability in organic synthesis. Commercially available organobromine pharmaceuticals include the vasodilator nicergoline, the sedative brotizolam, the anticancer agent pipobroman, and the antiseptic merbromin. SDS of cas: 615-55-4

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary

Visible Light-Mediated C-H Difluoromethylation of Electron-Rich Heteroarenes was written by Su, Yi-Ming;Hou, Yu;Yin, Feng;Xu, Yue-Ming;Li, Yan;Zheng, Xiaoqi;Wang, Xi-Sheng. And the article was included in Organic Letters in 2014.Application In Synthesis of Methyl 4-bromo-1-methyl-1H-pyrrole-2-carboxylate This article mentions the following:

In the presence of tris(2,2′-bipyridinyl)ruthenium(II) dichloride, electron-rich heteroarenes such as pyrroles, indoles, furans, and thiophenes underwent regioselective visible-light photochem. (phenylsulfonyl)difluoromethylation with PhSO₂CF₂I mediated by dipotassium hydrogen phosphate in CH₂Cl₂; desulfonylation with magnesium yielded the corresponding difluoromethylated products for nine of the (phenylsulfonyl)difluoromethylated products. Attempted (phenylsulfonyl)difluoromethylation of N-methylpyrrole in the presence of TEMPO, the exclusive formation of cyclization and ring-opening (phenylsulfonyl)difluoromethylated products derived from diallyl ether and (S)-(-)-β-pinene, resp., and the chemoselectivity of the (phenylsulfonyl)difluoromethylation were consistent with an electrophilic radical-mediated mechanism for the photochem. (phenylsulfonyl)difluoromethylation. In the experiment, the researchers used many compounds, for example, Methyl 4-bromo-1-methyl-1H-pyrrole-2-carboxylate (cas: 1196-90-3Application In Synthesis of Methyl 4-bromo-1-methyl-1H-pyrrole-2-carboxylate).

Methyl 4-bromo-1-methyl-1H-pyrrole-2-carboxylate (cas: 1196-90-3) belongs to organobromine compounds. A variety of minor organobromine compounds are found in nature, but none are biosynthesized or required by mammals. Organobromine compounds have fallen under increased scrutiny for their environmental impact. One prominent application of synthetic organobromine compounds is the use of polybrominated diphenyl ethers as fire-retardants, and in fact fire-retardant manufacture is currently the major industrial use of the element bromine.Application In Synthesis of Methyl 4-bromo-1-methyl-1H-pyrrole-2-carboxylate

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary

The effects of ortho substituents on reactivity. I. The alkaline hydrolysis of substituted ethyl phenylacetates was written by Watkinson, J. G.;Watson, William;Yates, B. L.. And the article was included in Journal of the Chemical Society in 1963.SDS of cas: 2178-24-7 This article mentions the following:

Rates of hydrolysis of ethyl phenylacetate and 24 nuclear-substituted derivatives have been measured at 24.8° in aqueous ethanol (85.4% by weight of ethanol). All the ortho substituents examined retard hydrolysis, even the nitro group which from the para position greatly accelerates it. Measurements at other temperatures show that the low rates are associated with high activation energies, and that the pre-exponential factor of the Arrhenius equation does not vary with substituents beyond the limits of exptl. error. Comparison of the results with those obtained with aqueous acetone (56% by weight of acetone) and with aqueous ethanol of different compositions as solvents reveals that the effects of substituents, and in particular of ortho substituents, are affected by the solvent. It is therefore suggested that an important factor in the retarding influence of ortho substituents in the alk. hydrolysis of ethyl phenylacetates is steric interference with solvation of the transition state. In the experiment, the researchers used many compounds, for example, Ethyl (2-bromophenyl)acetate (cas: 2178-24-7SDS of cas: 2178-24-7).

Ethyl (2-bromophenyl)acetate (cas: 2178-24-7) belongs to organobromine compounds. Bromine is more electronegative than carbon (2.9 vs 2.5). Consequently, the carbon in a carbon–bromine bond is electrophilic, i.e. alkyl bromides are alkylating agents. Bromine-containing agents predominate because not only are they more efficient than similar chlorine-containing species, but also the high atomic weight of bromine ensures that it is present in a high mass fraction within most organobromine compounds.SDS of cas: 2178-24-7

Referemce:
Bromide – Wikipedia,
bromide – Wiktionary