Month: December 2022

Hueckel, Walter published the artcileRates of cleavage and dipole moments of 1,2-dibromides, Quality Control of 594-81-0, the publication is Justus Liebigs Annalen der Chemie (1963), 17-30, database is CAplus.

cf. following abstract The rates of Br cleavage from 1,2-dibromocyclohexane, 1,2- (I), 2,3- (II), and 9,10-dibromo-trans-decalin (III), 2,3-dibromo-cis-decalin cleavage from 1,2-dibromocyclohexane, 1,2-, 2,3-, and 9,10-dibromo-trans-decalin (I), (II), and (III), 2,3-dibromo-cis-decalin (IV), 1,2-dibromo-1-methylcyclohexane, Me₂CBrCHBrMe, 1,2-dibromo-1,2-dimethylcyclohexane, and Me₂CBrCBrMe₂ by iodine-absolute MeOH were measured at 15-75° and related to the dipole moment. The rate depended on the type of CBr bond (secondary-secondary < secondary-tertiary < tertiary-tertiary; the rate constants of each group differed from those of the previous group by a factor of approx. 10². The conformation as derived from the dipole moment appeared of secondary significance. Quant., the differences in rate constant were too small to verify the 4-center principle for the transition state (Rice and Teller, CA 32, 7405⁶). Suitable, simple, isomeric trans-dibromides with the same C skeleton and fixed axial-axial, axial-equatorial, and equatorial-equatorial positions could not be obtained. The reaction product of 200 g. benzoquinone and 75 l. H₂C:CHCH:CH₂ was reduced without isolation, with 350 g. Zn dust in 900 ml. glacial HOAc to give 215 g. octalindione, m. 100-2° (1:1 petr. ether-C₆H₆), of which 60 g. treated with 70 g. KOH and 60 ml. 80% N₂H₄.H₂O in 500 ml. HOCH₂CH₂OH gave 33.5 g. Octalin, b. 67-73°, n²⁰_D 1.4847, n²⁵_D 1.4824. Of this 43 g., distilled through a spinning band column, collecting 2 g. fractions, gave: fractions 2-12, pure trans-Δ²-octalin, b₁₀ 67.5-8.0° (redistilled over Na, d₂₀ 0.89151, n²⁰_D 1.4815, n²⁵_D 1.4792, MR_D 43.52, m. -3.5°), and fractions 18-21, pure cis-Δ²-octalin, b₁₀ 73° (redistilled over Na, d₂₀ 0.92152, n²⁰_D 1.4936, MR_D 43.01). The appropriate octalin (10 g.) in 50 ml. anhydrous CHCl₃ was treated with 12 g. Br in 50 ml. CHCl₃ under anhydrous conditions, and the reaction mixture washed with NaHSO₃ and H₂O, dried, and evaporated to give a residue which was crystallized from EtOH and recrystallized to give the following decalins: II, m. 84.5-5.5° (EtOH or Me₂CO); I, m. 46° (EtOH, petr. ether, or Me₂CO); 2,3-dibromo-trans-decalin, m. 61° (30-50° petr. ether); trans-1,2-dibromo-cis-decalin, m. 37° (EtOH). 2,3(a,a)-Dibromo-trans-decalin heated 20 hrs. at 120° gave an equilibrium mixture which was separated by chromatography on Kieselgel eluting with petr. ether (b. 50-6°) to give starting material and 2,3(e,e)-dibromo-trans-decalin, m. 60°, which was reduced with Zn dust in EtOH at 65° to give pure trans-Δ²-octalin.

Justus Liebigs Annalen der Chemie published new progress about 594-81-0. 594-81-0 belongs to bromides-buliding-blocks, auxiliary class Bromide,Aliphatic hydrocarbon chain, name is 2,3-Dibromo-2,3-dimethylbutane, and the molecular formula is C6H12Br2, Quality Control of 594-81-0.

Referemce:
https://en.wikipedia.org/wiki/Bromide,
bromide – Wiktionary

Choi, Junwon published the artcileEngineering Orthogonal Polypeptide GalNAc-Transferase and UDP-Sugar Pairs, Quality Control of 69361-41-7, the publication is Journal of the American Chemical Society (2019), 141(34), 13442-13453, database is CAplus and MEDLINE.

O-Linked α-N-acetylgalactosamine (O-GalNAc) glycans constitute a major part of the human glycome. They are difficult to study because of the complex interplay of 20 distinct glycosyltransferase isoenzymes that initiate this form of glycosylation, the polypeptide N-acetylgalactosaminyltransferases (GalNAc-Ts). Despite proven disease relevance, correlating the activity of individual GalNAc-Ts with biol. function remains challenging due to a lack of tools to probe their substrate specificity in a complex biol. environment. Here, we develop a “bump-hole” chem. reporter system for studying GalNAc-T activity in vitro. Individual GalNAc-Ts were rationally engineered to contain an enlarged active site (hole) and probed with a newly synthesized collection of 20 (bumped) uridine diphosphate N-acetylgalactosamine (UDP-GalNAc) analogs to identify enzyme-substrate pairs that retain peptide specificities but are otherwise completely orthogonal to native enzyme-substrate pairs. The approach was applicable to multiple GalNAc-T isoenzymes, including GalNAc-T1 and -T2 that prefer nonglycosylated peptide substrates and GalNAcT-10 that prefers a preglycosylated peptide substrate. A detailed investigation of enzyme kinetics and specificities revealed the robustness of the approach to faithfully report on GalNAc-T activity and paves the way for studying substrate specificities in living systems.

Journal of the American Chemical Society published new progress about 69361-41-7. 69361-41-7 belongs to bromides-buliding-blocks, auxiliary class PROTAC Linker,Aliphatic Linker, name is (4-Bromobut-1-yn-1-yl)trimethylsilane, and the molecular formula is C7H13BrSi, Quality Control of 69361-41-7.

Referemce:
https://en.wikipedia.org/wiki/Bromide,
bromide – Wiktionary

Kahovec, L. published the artcileRaman effect. CXVII. Rotation isomerism. 9. Polyhaloalkanes, Recommanded Product: 2,3-Dibromo-2,3-dimethylbutane, the publication is Z. physik. Chem. (1940), 48-54, database is CAplus.

Results were obtained for Me₂CX₂, X = Br, I; MeCHXCH₂X, X = Cl, Br; ICH₂CH₂CH₂I; MeCHI₂; BrCH₂CHBr₂; MeCH₂CHMe₂; XMe₂CCMe₂X, X = Cl, Br. Increase in the number of frequencies around 800 cm.^-1 in the series of dihalopropanes and for the CX valence vibrations in the trihaloethanes is attributed to rotation isomerism.

Z. physik. Chem. published new progress about 594-81-0. 594-81-0 belongs to bromides-buliding-blocks, auxiliary class Bromide,Aliphatic hydrocarbon chain, name is 2,3-Dibromo-2,3-dimethylbutane, and the molecular formula is C6H12Br2, Recommanded Product: 2,3-Dibromo-2,3-dimethylbutane.

Referemce:
https://en.wikipedia.org/wiki/Bromide,
bromide – Wiktionary

Kminek, Ivan published the artcileLow-band gap copolymers containing thienothiadiazole units: synthesis, optical, and electrochemical properties, Recommanded Product: 2,5-Dibromo-3,4-dinitrothiophene, the publication is Journal of Polymer Science, Part A: Polymer Chemistry (2010), 48(13), 2743-2756, database is CAplus.

Novel low-band gap alternating copolymers consisting of 9,9-bis(2-ethylhexyl)fluorene and 4,6-di(2-thienyl)thieno[3,4-c][1,2,5]thiadiazole and its 3,3”-dialkyl derivatives were synthesized by Suzuki copolymerization reaction, and their photophys. and electrochem. properties were studied. The copolymers possess small optical band gap 1.3-1.4 eV. The absorption covers the whole visible spectral region. The long-wavelength absorption maxima in thin films located at approx. 750-785 nm are significantly red shifted compared with those in solution, indicating strong intermol. interactions. The introduction of alkyl chains to the thiophene units increases the mol. weights of soluble fractions and solubility of the final copolymers, leading to the improved processability of thin films. Polymer solutions exhibited solvatochromism and thermochromism, which is strongly supported by the involvement of the alkyl chains. The copolymers exhibited ambipolar redox properties and reversible electrochromic behavior. The electronic properties are influenced only slightly by alkyl substituents.

Journal of Polymer Science, Part A: Polymer Chemistry published new progress about 52431-30-8. 52431-30-8 belongs to bromides-buliding-blocks, auxiliary class Liquid Crystal &OLED Materials, name is 2,5-Dibromo-3,4-dinitrothiophene, and the molecular formula is C4Br2N2O4S, Recommanded Product: 2,5-Dibromo-3,4-dinitrothiophene.

Referemce:
https://en.wikipedia.org/wiki/Bromide,
bromide – Wiktionary

Cimrova, Vera published the artcileDonor-acceptor copolymers containing bithiophene and dithiophenylthienothiadiazole units with fast electrochromic response, Quality Control of 52431-30-8, the publication is Journal of Materials Chemistry C: Materials for Optical and Electronic Devices (2019), 7(28), 8575-8584, database is CAplus.

New low-bandgap donor-acceptor (D-A) functional copolymers, CDTDBT and CEHTDBT, composed of a 3,3′-didodecyl-2,2′-bithiophene donor and 4,6-bis(3′-dodecylthiophene-2′-yl)thieno[3,4-c][1,2,5]thiadiazole (DT) or 4,6-bis(3′-(2-ethylhexyl)thiophene-2′-yl)thieno[3,4-c][1,2,5]thiadiazole (EHT) acceptor structural units, resp., were synthesized by Stille coupling of the corresponding comonomers. The influence of decyls or branched 2-ethylhexyls chains attached to the thiophenes of the 4,6-bis(3′-alkylthiophene-2′-yl)thieno[3,4-c][1,2,5]thiadiazole on the photophys., thermochromic, electrochem., and spectroelectrochem. properties are reported and discussed in comparison to a series of D-A copolymers with various donor units and the corresponding dithiophenylthienothiadiazole (DT or EHT) acceptor units. The new copolymers, CDTDBT and CEHTDBT, exhibit interesting electrochromic behaviors with fast response times, which reach full optical contrast in 0.3 s. These new copolymers have the potential to be used for optical switching.

Journal of Materials Chemistry C: Materials for Optical and Electronic Devices published new progress about 52431-30-8. 52431-30-8 belongs to bromides-buliding-blocks, auxiliary class Liquid Crystal &OLED Materials, name is 2,5-Dibromo-3,4-dinitrothiophene, and the molecular formula is C4Br2N2O4S, Quality Control of 52431-30-8.

Referemce:
https://en.wikipedia.org/wiki/Bromide,
bromide – Wiktionary

Vereshchagin, A. N. published the artcileAnisotropy of polarizability and dipole moments of some 1,2-dibromoethane derivatives, Quality Control of 594-81-0, the publication is Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya (1973), 163-5, database is CAplus.

Kerr constants and dipole moments of BrRR1CCR2R3Br (I, R-R3 = H, Me, Ph) were reported. The trans conformers of such compounds had effective dipole moments that could not be described by the simple moment-additive scheme. The Me-substituted I in solution were mainly in transform whereas Ph shifted the conformational equilibriumsubstantially by destabilizing the trans location of the 2 Br atoms probably by gauche interaction of Ph and Br components. This interaction was ∼1.2 cal/mole.

Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya published new progress about 594-81-0. 594-81-0 belongs to bromides-buliding-blocks, auxiliary class Bromide,Aliphatic hydrocarbon chain, name is 2,3-Dibromo-2,3-dimethylbutane, and the molecular formula is C38H24F4O4P2, Quality Control of 594-81-0.

Referemce:
https://en.wikipedia.org/wiki/Bromide,
bromide – Wiktionary

Lednicer, Daniel published the artcile4-Amino-4-arylcyclohexanones and their derivatives: a novel class of analgesics. 2. Modification of the carbonyl function, Quality Control of 18928-94-4, the publication is Journal of Medicinal Chemistry (1981), 24(4), 404-8, database is CAplus and MEDLINE.

The cyclohexanols I (R = H, alkyl, alkenyl, alkynyl, PhCH₂, PhCH₂CH₂, etc.; R¹ = H, Cl, Br, Me), prepared by the reduction of or addition of nucleophiles to the corresponding cyclohexanones, were separated into cis and trans isomers and tested for analgesic activity. The trans (OH and N) isomers were invariably more potent than the cis. I (R = PhCH₂CH₂) are among the most potent opioids reported to date; possibly the ring system may be providing an addnl. binding site for these compounds, and thus greatly enhance their affinity for the opioid receptor.

Journal of Medicinal Chemistry published new progress about 18928-94-4. 18928-94-4 belongs to bromides-buliding-blocks, auxiliary class Bromide,Aliphatic cyclic hydrocarbon, name is (2-Bromoethyl)cyclopentane, and the molecular formula is C7H13Br, Quality Control of 18928-94-4.

Referemce:
https://en.wikipedia.org/wiki/Bromide,
bromide – Wiktionary

Dower, William V. published the artcileThermal conversion of 1,5,9-triynes. [2 + 2 + 2] Cycloadditions or [3.3]sigmatropic shifts?, Product Details of C7H13BrSi, the publication is Tetrahedron (1986), 42(6), 1873-81, database is CAplus.

The gas phase pyrolysis products [labeled and unlabeled naphthalene and [1,2:4,5]dicyclobutabenzene or hexaradialene] of RCC(CH₂)₂CC(CH₂)₂CCR [R = H, D (I)] and HCC(CH₂)₂¹³C¹³C(CH₂)₂CCH (II) or 1,5,9-cyclododecatriyne (III) and III–1,10–¹³C₂ (IV), examined at 400-600°/10^-4-40 tor with ∼1 ms-15 s contact times, show that the mechanism involves a series of [3.3] sigmatropic shifts; [2 + 2 + 3] cycloadditions of the alkyne units do not occur. The preparation of I, II, III, and IV are discussed.

Tetrahedron published new progress about 69361-41-7. 69361-41-7 belongs to bromides-buliding-blocks, auxiliary class PROTAC Linker,Aliphatic Linker, name is (4-Bromobut-1-yn-1-yl)trimethylsilane, and the molecular formula is C7H13BrSi, Product Details of C7H13BrSi.

Referemce:
https://en.wikipedia.org/wiki/Bromide,
bromide – Wiktionary

Donkervoort, Johannes G. published the artcileNovel organomanganese(II) complexes active as homogeneous catalysts in manganese(II)/copper(I) catalyzed carbon-carbon bond formation reactions, Name: (4-Bromobut-1-yn-1-yl)trimethylsilane, the publication is Recueil des Travaux Chimiques des Pays-Bas (1996), 115(11/12), 547-548, database is CAplus.

Novel organomanganese complexes 2,6-(Me₂NCH₂)₂C₆H₂X (I; X = MnLiCl₂), prepared from I (X = Li) and MnCl₂, reacted with RLi (R = Me, Bu, Ph) to give the corresponding I (X = R). These new complexes are active catalysts with CuCl for cross-coupling reactions of R¹Br [R¹ = n-C₈H₁₇, BuCO(CH₂)₁₀, EtO₂CCH₂CH₂, CH₂:CHCH₂CH₂. Me₃SiCCCH₂CH₂] with R²MgCl (R² = Me₂CH, Bu, EtCHMe, Me₃C, n-C₁₄H₂₉) to give 8 corresponding R¹R² in 75-92% yield.

Recueil des Travaux Chimiques des Pays-Bas published new progress about 69361-41-7. 69361-41-7 belongs to bromides-buliding-blocks, auxiliary class PROTAC Linker,Aliphatic Linker, name is (4-Bromobut-1-yn-1-yl)trimethylsilane, and the molecular formula is C7H13BrSi, Name: (4-Bromobut-1-yn-1-yl)trimethylsilane.

Referemce:
https://en.wikipedia.org/wiki/Bromide,
bromide – Wiktionary

Donkervoort, Johannes G. published the artcileNovel tridentate diamino organomanganese(II) complexes as homogeneous catalysts in manganese(II)/copper(I) catalyzed carbon-carbon bond forming reactions, Name: (4-Bromobut-1-yn-1-yl)trimethylsilane, the publication is Journal of Organometallic Chemistry (1998), 558(1-2), 61-69, database is CAplus.

The new, paramagnetic arylmanganese(II) complex Li[MnCl₂(NCN)] (2, NCN = [C₆H₃(CH₂NMe₂)₂-2,6]^–) was obtained in high yield from the reaction of MnCl₂ and [Li(NCN)]₂ in a 2:1 molar ratio. In THF solution, 2 is likely an ionic species [Li(THF)_n][MnCl₂(NCN)] (mol. weight determination and conductivity measurements), while magnetic measurements indicate that a high spin d⁵ Mn(II) center is present. Subsequent reaction of 2 with RLi afforded [MnR(NCN)] (R = Me, Bu). Complex 2, using CuCl as a co-catalyst, is an effective catalyst system for cross-coupling of Grignard reagents with alkyl bromides and the 1,4-addition of organomagnesium halides to α,β-unsaturated ketones. No further additives or co-solvents are necessary. For both reactions a dramatic decrease in reaction times is observed when compared to standard Mn/Cu systems. Alkyl bromides with unsaturated or heteroatom functionalities can be cross-coupled. Also, excellent reactivity towards normally unreactive β,β-disubstituted ketones was observed in the 1,4-addition reaction.

Journal of Organometallic Chemistry published new progress about 69361-41-7. 69361-41-7 belongs to bromides-buliding-blocks, auxiliary class PROTAC Linker,Aliphatic Linker, name is (4-Bromobut-1-yn-1-yl)trimethylsilane, and the molecular formula is C7H13BrSi, Name: (4-Bromobut-1-yn-1-yl)trimethylsilane.

Referemce:
https://en.wikipedia.org/wiki/Bromide,
bromide – Wiktionary