Tag: M.W=200-250

Hine, Jack published the artcileEffect of halogen atoms on the reactivity of other halogen atoms in the same molecule. IV. The mechanism of the transformation of vicinal dihalides to olefins by reaction with iodide ion, Computed Properties of 594-81-0, the publication is Journal of the American Chemical Society (1955), 361-4, database is CAplus.

cf. C.A. 48, 10531g. It is shown that the dehalogenation of (CH₂Br)₂, MeCHBrCH₂Br, and EtCHBrCH₂Br by iodide ions is largely initiated by an S_N2 attack to form a bromoiodide which is directly dehalogenated. The dehalogenation of the 2,3-dibromobutanes is believed to be largely direct, as previously suggested. In evidence is the fact that (CH₂Br)₂ is the most reactive of the dibromides mentioned. Furthermore it is shown that the rate constant for the reaction of (CH₂Br)₂ is in excellent agreement with that which would be predicted for the S_N2 reaction of the compound with iodide ion under the conditions employed. It is improbable that a very large fraction of the reaction follows a path involving the formation of a vicinal diiodide. It is proposed that the dehalogenation reaction proper involves the formation of an intermediate in which 1 of the halogen atoms is bound equally to 2 C atoms. F(CH₂)₂Br (about 0.01 mole) was weighed into about 48 cc. MeOH, the solution equilibrated at 40°, mixed with 50 cc. 0.1M KI in MeOH (40°), the mixture diluted to 100 cc., and the iodide ion concentration determined within a few min., by withdrawing a 5-cc. sample and titrating with KIO₃ in cold concentrated HCl; the rate constant was in 2 similar runs 5.49 ± 0.30 and 5.74 ± 0.06 × 10^-6 sec.^-1 mole^-1; no observable amount of iodine was formed in either run.

Journal of the American Chemical Society 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, Computed Properties of 594-81-0.

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

Dong, Yaxi published the artcileCu-Catalyzed C-H Allylation of Benzimidazoles with Allenes, Related Products of bromides-buliding-blocks, the publication is Organic Letters (2021), 23(17), 6765-6769, database is CAplus and MEDLINE.

CuH-catalyzed intramol. cyclization and intermol. allylation of benzimidazoles with allenes have been described. The reaction proceeded smoothly with the catalytic system of Cu(OAc)₂/Xantphos and catalytic amount of (MeO)₂MeSiH. This protocol features mild reaction conditions and a good tolerance of substrates bearing electron-withdrawing, electron-donating, or electron-neutral groups. A new catalytic mechanism was proposed for this copper hydride catalytic system.

Organic Letters published new progress about 53484-26-7. 53484-26-7 belongs to bromides-buliding-blocks, auxiliary class Bromide,Nitro Compound,Amine,Benzene, name is 4-Bromo-N-methyl-2-nitroaniline, and the molecular formula is C7H7BrN2O2, Related Products of bromides-buliding-blocks.

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

Russell, Glen A. published the artcileDirective effects in aliphatic substitutions. III. The photobromination of branched-chain hydrocarbons; the dark reaction of bromine with tertiary alkyl bromides, Recommanded Product: 2,3-Dibromo-2,3-dimethylbutane, the publication is Journal of the American Chemical Society (1955), 4025-30, database is CAplus.

The photobromination of hydrocarbons in the liquid phase is highly selective and constitutes an excellent method for the preparation of tertiary bromides from hydrocarbons which contain only primary and tertiary H atoms. The presence of secondary or an addnl. tertiary H atom in the adjacent position leads to the formation of considerable amounts of dibromides. It is proposed that these dibromides arise from an ionic or mol. reaction of Br with the tertiary bromide formed in the initial photochem. reaction. The dark reaction of Br with Me₃CBr exhibits 3rd order kinetics. No evidence could be obtained of a measurable equilibrium between olefin and hydrogen halide in solutions of Me₃CBr and Me₃CCl in refluxing SO₂ or of Me₂CBrCMe₃ (XVII) in CCl₄ at 76°. Yet Br reacts rapidly with the tertiary halides under these conditions. These results are consistent with a reaction mechanism in which a Br mol. brings about the ionization of the tertiary bromide, followed by reaction of a 2nd Br mol. with the high-energy π-complex form of the carbonium ion. Me₃CCHMe₂ (XVIII), b₇₄₅ 80.3°, n_D²⁰ 1.3895 (1 mol) irradiated with a 150-w. clear light bulb (1 in. from the flask) and treated 1.5 h. with 0.25 mol Br at 80°, 25 g. XVIII distilled off, the residue cooled, and the nearly solid crystalline mass (57 g.) washed with 50 cc. cold XVIII gave 36 g. XVII, m. 149-50° (sealed tube), and 10 g. XVIII by vacuum sublimation at 80°/25 mm. Cumene (XIX) (1 mol), b₇₄₀ 151.4-5°, n_D²⁰ 1.4915, brominated similarly 0.5 h. with 0.5 mol Br at 60°, and the mixture bubbled with N to remove the HBr and analyzed for total and hydrolyzable Br (80% EtOH at 25°) showed that 73% of the Br was present as the tertiary bromide. A similar run with 0.25 mol Br/mol XIX gave during 1.5 h. at 0° a product containing 94% of the Br as tertiary bromide; the bromide could not be crystallized from the solution at -80° and attempts to distil below 1 mm. resulted in dehydrobromination. Br (0.5 mol) added under illumination to 0.5 mol XIX in CH₂Cl₂ at 0° until the Br color persisted 2 min. after the addition of 1 drop Br and the product rectified gave 111 g. MePhCBrCH₂Br, b₁₆ 120-20.5°. Br (0.5 mol) added to 2 mol (Me₂CH)₂ (XX), n_D²⁰ 1.3749, at 55° during 6 h. at such a rate that the hydrocarbon remained colorless through the reaction, the mixture cooled, and the crystalline deposit (65 g.) sublimed at 95-100°/5 mm. gave 54 g. (Me₂CBr)₂ (XXI), m. 169-71° (sealed tube). Br (0.5 mol) added dropwise at 60° during 8 h. to 2 mol Me₂CHPr (XXII), n_D²⁰ 1.3714, at such a rate that the solution was nearly colorless at all times, and the mixture fractionated gave 64 g. mixture of 92% Me₂CHBrPr and 8% secondary bromides from XXII, and 10 g. material, b₄₀ 92-2.5°, containing 64.5% Br, largely as Me₂CBrCHBrEt. XVII (0.075 mol) in 100 g. CCl₄ treated 40 h. at 25° with 0.076 mol dry Br, the CCl₄ removed, the mixture sublimed in vacuo to remove 2 g. unchanged XVII, and the residue distilled gave 10.3 g. dibromide, b₁₀ 88.5-9.5°, presumably BrCH₂CMeBrCMe₃, and 3 g. tribromides, b₃ 107-10°. Br (0.25 mol) and 0.25 mol Me₂CBrEt in 120 cc. CCl₄ held 40 h. at 25° in the dark and the mixture distilled gave 34 g. Me₂CBrCHBrMe, b₃₀ 72.5-73°, n_D²⁰ 1.5095, and 8.5 g. tribromide, b₁₅ 110-14°. Me₂C(OH)CHMe₂ (XXIII), b₁₀₀ 65.5, n_D²⁰ 1.4182, (10.2 g.) as a 2M solution in CCl₄ treated with Br 60 h. in the dark and the product crystallized and rectified gave 18.2 g. XXI, m. 168-9°, 2.1 g. unchanged XXIII, 1 g. tribromide, b₂₅ 140-50°, and traces of a lachrymator. A similar run with 16 g. Br and 10.2 g. XXIII in the presence of 10 g. finely divided CaCO₃ showed only 80% reaction of the Br in 72 h. and gave 10 g. dibromide, 5 g. XXIII, and 4 g. high-boiling material, presumably a tribromide. Me₃CBr (40 g.) and 46 g. Br held 42 h. at 0° in the dark and the mixture distilled gave 43 g. Me₂CBrCH₂Br, b. 146-9°, and 6 g. higher-boiling material, probably the tribromide. Br (15.984 and 13.700 g. Me₃CBr diluted to 100 cc. at 0° with CCl₄, 5-cc. samples sealed in ampuls, stored in ice, and 1-cc. aliquots titrated with standard Na₂S₂O₃ at appropriate intervals gave the kinetic data for the bromination; average k₃ × 10² l.²/mol²/h. 0.52. Photobrominations at 25° were carried out with 5 mol % solutions by degassing the appropriate hydrocarbon with N, vaporizing dry Br in a stream of N, passing the Br-N mixture during 1 h. into the hydrocarbon, removing the HBr with N, and analyzing the mixture (the Br used, the total bromide, and the tertiary bromide, all in moles, given): XIX, 0.055, 0.0541, 0.0541; XVIII, 0.050, 0.0486, 0.0457; XXII, 0.051, 0.0492, 0.0443; XX, 0.051, -, 0.0214 (some dibromide crystallized during the bromination); XX, 0.031, 0.0302, 0.0238; XX (0°), 0.038, 0.0371, 0.0326. Me₃CCl (5 cc.) added during 6 h. to 15 cc. SO₂ refluxing at -12.5 ± 0.5°, and 100 cc. vapor removed under standard conditions and analyzed in a mass spectrometer showed that not more than 0.001% Me₃CCl had been dehydrochlorinated. Me₃CBr (5 g.) treated 6 h. with 25 cc. SO₂ refluxing at -14 ± 0.5°/722 mm. was less than 0.001% dehydrobrominated. XVII (500 cc. 0.2M solution in CCl₄) rectified at atm. pressure, 400 cc. CCl₄ removed during 24 h., all gases formed passed into aqueous NaOH, and the distillate extracted with H₂O indicated the complete absence of acidic materials or bromide ion. Me₂CBrEt (5 cc.), 25 cc. CH₂Cl₂, and 2 g. iodine refluxed at such a pressure that the temperature was 25°, and 100 cc. vapor removed under a high reflux ratio during 6 h. and analyzed showed less than 0.001% dehydrobromination.

Journal of the American Chemical Society 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

Davies, Jonathan A. published the artcileTotal synthesis of Kalimantacin A, Application In Synthesis of 69361-41-7, the publication is Organic Letters (2020), 22(16), 6349-6353, database is CAplus and MEDLINE.

The kalimantacins make up a family of hybrid polyketide-nonribosomal peptide-derived natural products that display potent and selective antibiotic activity against multidrug resistant strains of Staphylococcus aureus. Herein, we report the first total synthesis of kalimantacin A, in which three fragments are prepared and then united via Sonogashira and amide couplings. The enantioselective synthetic approach is convergent, unlocking routes to further kalimantacins and analogs for structure-activity relationship studies and clin. evaluation.

Organic Letters 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, Application In Synthesis of 69361-41-7.

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

Pardo-Rodriguez, Virtudes published the artcilePd-catalyzed borylative cyclisation of 1,7-enynes, HPLC of Formula: 69361-41-7, the publication is Chemical Communications (Cambridge, United Kingdom) (2012), 48(85), 10517-10519, database is CAplus and MEDLINE.

A variety of 1,7-enynes undergo nucleophilic boration and cyclization with bis(pinacolato)diboron catalyzed by Pd bis(trifluoroacetate), affording alkylidenecyclohexane-substituted homoallylic and allylic boronates by formation of C-C and C-B bonds. Reaction of CR³R⁴:CR²CH₂XYCH₂CCR¹ [X = C(CO₂Me)₂, C(SO₂Ph)₂, Y = CH₂; X = CH₂, Y = C(CO₂Me)₂, NTs] with pin₂B₂, catalyzed by Pd(TFA)₂ gave methylenecyclohexanes I (2a–i, 4a–h, R¹ = H, Me, Ph, TMS; R²-R⁴ = H, Me, CH₂OAc) together with cyclohexenylmethyl boronates II [5, Y = C(CO₂Me)₂, NTs]. The reaction mechanism comprises palladium addition to the triple bond with subsequent formation of palladaindene and elimination; the compounds 5 were rationalized as products of palladium-catalyzed isomerization of 4.

Chemical Communications (Cambridge, United Kingdom) 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, HPLC of Formula: 69361-41-7.

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

Nelson, David A. published the artcileUse of fluorescent 1,3-disubstituted 2(1H)-pyridones for environmental analysis, Category: bromides-buliding-blocks, the publication is ACS Symposium Series (1989), 383(Lumin. Appl. Biol.), 206-27, database is CAplus.

Fluorescent derivatives were prepared from a series of alkyl halides and alcs. using derivatizing reagents prepared from 3-carbamoyl-2(1H)-pyridone and 3-phenyl-2(1H)-pyridone. These derivatives were designed to be analyzed by HPLC using fluorescence detection, and they could be measured at the picomole level. The derivatization chem. is applicable to a wide variety of organic compounds Derivatives were also prepared from amines, phenols, acrylonitrile, and heptachlor. A series of 6 pyridonesulfonates was synthesized for use as fluorescent, site-specific, water-tracing compounds

ACS Symposium Series published new progress about 55788-44-8. 55788-44-8 belongs to bromides-buliding-blocks, auxiliary class Bromide,Salt,Aliphatic hydrocarbon chain,Aliphatic hydrocarbon chain, name is Sodium 3-bromopropane-1-sulfonate, and the molecular formula is C3H6BrNaO3S, Category: bromides-buliding-blocks.

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

Fan, Ye published the artcileReversible-Tuning Krafft Temperature of Selenium-Containing Ionic Surfactants by Redox Chemistry, Computed Properties of 55788-44-8, the publication is Langmuir (2020), 36(13), 3514-3521, database is CAplus and MEDLINE.

An easy, effective, and reversible strategy for tuning the Krafft temperature (K_T) of selenium-containing ionic surfactants, with head groups ranging in nature from anionic to amphoteric, has been achieved for the first time via the redox chem. of selenium. After oxidation with H₂O₂, the selenide group was converted to a more hydrophilic selenoxide group. This made the oxidized forms of the surfactants more water-soluble, which results in a marked reduction in the K_T. In contrast, the hydrophilic selenoxide was restored to its reduced form of selenide via reduction reaction, which allowed the K_T value to return to its initial value. By alternating the oxidization and reduction treatments, the K_T of the selenium-containing surfactants in this work could be reversibly switched over 5-10 cycles without causing obvious adverse distortions.

Langmuir published new progress about 55788-44-8. 55788-44-8 belongs to bromides-buliding-blocks, auxiliary class Bromide,Salt,Aliphatic hydrocarbon chain,Aliphatic hydrocarbon chain, name is Sodium 3-bromopropane-1-sulfonate, and the molecular formula is C3H6BrNaO3S, Computed Properties of 55788-44-8.

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

Cakar, Ayse Erdogan published the artcileDetermination of the surface thermodynamic characteristics and the structural isomer separation ability of new synthesized phenylbenzoate-based three-ring calamitic liquid crystals by inverse gas chromatography, HPLC of Formula: 143-15-7, the publication is Journal of Molecular Structure (2022), 133379, database is CAplus.

Two different new calamitic liquid crystals (LCs), 4-[4-(((S)-3,7-dimethyloctyloxy)phenoxy)carbonyl]phenyl 4-(n-decyloxy)benzoate (DPDEB) and 4-[4-(((S)-3,7-dimethyloctyloxy)phenoxy)carbonyl]phenyl 4-(n-dodecyloxy)benzoate (DPDOB) were synthesized and characterized using ¹H-NMR, and ¹³C-NMR. The LC behavior of the target compounds was investigated by optical polarization microscopy (PM) and differential scanning calorimetry (DSC). The selectivity coefficients, a, of the structural isomers at infinite dilution for the DPDEB and DPDOB LCs were determined for Bu acetate, Bu alc. and amyl alc. isomers. Surface energy anal. has been performed using inverse gas chromatog. (IGC). By using suitable solvents, the surface properties and separation power of isomers of DPDEB and DPDOB LCs were determined between 303.2 and 323.2 K. Experiments with LC’s have been conducted at infinite dilution to the specific adsorption enthalpy and the specific adsorption free energy. IGC measurements exhibited values of acidity constants (K_A) of 0.033 and 0.057 and basic constants (K_D) of 0.176 and 0.242 for DPDEB and DPDOB, resp. It has been found that all LCs show basic character.

Journal of Molecular Structure published new progress about 143-15-7. 143-15-7 belongs to bromides-buliding-blocks, auxiliary class Bromide,Aliphatic hydrocarbon chain, name is 1-Bromododecane, and the molecular formula is C12H25Br, HPLC of Formula: 143-15-7.

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

Hussain, Nazar published the artcileSynthesis of Sugar-Based Enones and Their Transformation into 3,5-Disubstituted Furans and 2-Acyl-Substituted 1,2,3-Trideoxy Sugars in the Presence of Lewis Acids, Recommanded Product: 2-Bromo-5-methoxybenzene boronic acid, the publication is Organic Letters (2019), 21(9), 3034-3037, database is CAplus and MEDLINE.

Pd-catalyzed carbonylative cross-coupling reactions of 2-iodoglycals have been developed for the synthesis of sugar-based arylones and ynones using formic acid as the carbonyl source. Whereas acetyl-protected arylones lead to the formation of highly substituted furan derivatives in the presence of Lewis acid, benzyl-protected arylones furnished the 3-deoxy sugar derivative In the presence of nucleophiles, an attack took place on the C-1 or C-3 carbon regio- and stereoselectively depending on the nature of the nucleophiles.

Organic Letters published new progress about 89694-44-0. 89694-44-0 belongs to bromides-buliding-blocks, auxiliary class Bromide,Boronic acid and ester,Benzene,Ether,Boronic Acids,Boronic acid and ester, name is 2-Bromo-5-methoxybenzene boronic acid, and the molecular formula is C7H8BBrO3, Recommanded Product: 2-Bromo-5-methoxybenzene boronic acid.

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

Parker, A. J. published the artcileE2C mechanism in elimination reactions. II. Substituent effects on rates of elimination from acyclic systems, SDS of cas: 594-81-0, the publication is Journal of the American Chemical Society (1971), 93(19), 4735-49, database is CAplus.

The effects of alkyl, aryl, benzyl, bromine, and carbomethoxy substituents on rates of bimol.β-eliminations are reported. A spectrum of transition states, ranging from E2H-like to E2C-like, is utilized and the response of the various transition states to substituent effects is very different. The E2C-like transition state is very product-like. E2C-like reactions give high yields of the most stable isomer (e.g., Saytzeff or trans-olefin) provided that the requirement of anti geometry of β-hydrogen and leaving group is not violated. Tetrabutylammonium acetate in acetone is an excellent base system for promoting fast clean β-elimination from secondary or tertiary acyclic systems.

Journal of the American Chemical Society 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, SDS of cas: 594-81-0.

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