Continuous, homogeneous and rapid synthesis of 4-bromo-3-methylanisole in a modular microreaction system

4-Bromo-3-methylanisole is mainly used to synthesize black fluorane dye(2-anilino-3-methyl-6-dibutylaminofluorane, ODB-2), which is one of the most important heat and pressure-sensitive dyes in the manufacture of thermal papers. Compared to the industrial heterogeneous batch process, a continuous homogeneous bromination technology in a modular microreaction system has been developed, and 4-bromo-3-methylanisole has been successfully prepared through high-selective mono-bromination of 3-methylanisole with Br2 solution in CHCl3. In optimal conditions, the content of bis-brominated byproducts can be controlled less than 0.5%,which is superior to the industrial standard with 99.5% 3-methylanisole conversion at very short residence time and mild reaction temperature.

Synthesis of 1-Bromo-3-methoxy-4-propoxy-5-iodobenzene——A Novel Efficient Process for the Synthesis of Brominated Aromatic Compound

The reaction of aromatic carboxylic acid with oxalyl chloride gives rise to the corres- ponding acid chloride which without purification is treated with the sodium salt of mercapto- pyridine oxide in the presence of 2,2-azo-bisisobutyronitrile (AIBN), radical initiator to give a brominated aromatic compound. After etherification and oxidation, 5-iodovaniline was converted to trisubstituted benzene carboxylic acid which give 1-bromo-3-methoxy-4-propoxy-5-iodo- benzene by this new brominating process with a yield of 74 %.

Synthesis,Crystal Structure and Anticancer Property of (Z)-N-(4-Bromo-5-ethoxy-3,5-dimethyl-furan-2(5H)-ylidene)-4-methylbenzenesulfonamide

The novel title compound（Z）-N-（4-bromo-5-ethoxy-3,5-dimethylfuran-2（5H）-yli-dene）-4-methylbenzenesulfonamide 1（C15H18BrNO4S） has been unexpectedly synthesized by the aminohalogenation reaction of ethyl 2-methylpenta-2,3-dienoate with TsNBr2,and characterized by mp,IR,1H NMR,EIMS,ESIHRMS and single-crystal X-ray diffraction.It crystallizes in mono-clinic,space group P21/c with a = 11.714（5）,b = 14.106（5）,c = 10.402（4） ,β = 97.298（8）°,V = 1704.9（12） 3,Mr = 388.27,Z = 4,Dc = 1.513 g/cm3,μ（MoKα） = 2.549 mm-1,F（000） = 792,the final R = 0.033 and wR = 0.062 for 3098 observed reflections（Ⅰ 〉 2σ（Ⅰ））.

Synthesis, Crystal Structure and Biological Activities of 3-Bromo-5-(4-chlorophenyl)-4-cyanopyrrole-N,N-dimethyl-2-carboxamide

The title compound 3-bromo-5-（4-chlorophenyl）-4-cyanopyrrole-N,N-dimethyl-2-amide（3） was synthesized with 4-bromo-2-（4-chlorophenyl）-5-（trifluoromethyl）-1H-pyrrole-3-carbonitrile（1） and N,N-dimethylformamide（2） by the α-C acylation reaction catalyzed by potassium t-butoxide, and characterized by IR, 1H-NMR and X-ray single-crystal diffraction. It crystallizes in monoclinic, space group P2（1/n）with a = 12.789（2）, b = 13.783（2）, c = 17.980（3） °, β = 109.230（3）°, V = 2992.5 A3, Mr = 352.62, Dc = 1.565 mg/m3, Z = 8, m = 2.924 mm-1, F（000） = 1408, the final R = 0.0424 and w R = 0.0973 for 3518 observed reflections with I 〉 2σ（I）. A total of 23559 reflections were collected, of which 6242 were independent（Rint = 0.0566）. The insecticidal, herbicidal and antibacterial activities of compound 3 were determined, and the experimental results showed that the mortality of 3 at the concentration of 100 ppm on the Fipronil against Linnaeus was 76.6%, the growth inhibition rate of 3 against Cynodon Dactylon under the condition of 100 ppm was 35.8% and the inhibitory activity of 3 at the concentration of 25 ppm against Fusarium graminearum reached 50.9%. Hence, the title compound has the value of further research and application prospect.

Theoretical Study on the Reaction Mechanism of 2-Methoxybenzaldehyde,4-Bromo-indanone,Malononitrile and Ammonium Acetate One-pot to Form 6-(2-Methoxyphenyl)-2-amino-6-bromo-5H-indeno[1,2-b]pyridine-3-carbonitrile

The reaction mechanism of 2-methoxybenzaldehyde, 4-bromo-indanone, malononitrile and ammonium acetate one-pot to form 6-（2-methoxyphenyl）-2-amino-6-bromo-5 Hindeno[1,2-b]pyridine-3-carbonitrile was studied by density functional theory. The geometries of the reactants, transition states, intermediates and products were optimized at the PW91/DNP level. Vibration analysis was carried out to confirm the transition state structure. Reaction pathways were investigated in this study. The result indicates that the reaction Re→ TSB1→IMB1→ TSB2→ IMB2→TSB3→IMB3→TSB4→IMB4→TSB5→IMB5→TSB6→IMB6→TSB7→IMB7→ TSB8→IMB8→TSB9→IMB9→P2 is the main pathway, the activation energy of which is the lowest. The dominant product predicted theoretically is in agreement with the experiment results.

Synthesis and Crystal Structure of 4-Bromo-5-ethoxy-3-methyl-5- (naphthalen-1-yl)-1-tosyl-1H-pyrrol-2(5H)-one

The title compound 4-bromo-5-ethoxy-3-methyl-5-（naphthalen-l-yl）-l-tosyl-lH- pyrrol-2（5H）-one 1 （C24H22BrNO4S, Mr = 500.40） has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction analysis. It crystallizes in monoclinic, space group P21/n with a = 8.8562（15）, b = 18.118（3）, c = 14.055（2）A, β = 99.855（3）^o, V= 2221.9（6）A3, Z = 4, Dc = 1.496 g/cm^3,μ= 1.975 mm^-1, 2 = 0.71073A, F（000） = 1024, R = 0.0607 and wR = 0.1371.

Synthesis of 6-Alkylidene-5,6-dihydro-4H-1,3-thiazine Derivatives via the Cyclization of N-3-Bromo-3-alkenylthioamides

By the treatment of N-3-bromo-3-alkenylthioamides with sodium hydroxide in DMF-H2O in the presence of tetra-butylammonium bromide,series of 6-alkylidene-5,6-dihydro-4H-1,3-thiazine derivatives were prepared in moderate to good yields.The cyclization is supposed to proceed via both the intramolecular vinylic nucleophilic substitution and the elimination-addition mechanisms(formation of acetylenic intermediates)in a competitive manner.

Facile One-pot Synthesis of Ethyl 3-Alkyl-4-hydroxy-2-thioxothiazolidine-4-carboxylates

Ethyl 3-alkyl-4-hydroxy-2-thioxothiazolidine-4-carboxylates were prepared in excellent yields from the reaction of corresponding primary amines with carbon disulfide and ethyl 3-bromo-2-oxopropanoate in the presence of anhydrous potassium phosphate in DMF at room temperature within 1 h. The structures of the highly functionalized products were corroborated spectroscopically （IR, ^1H NMR, ^13C NMR, EI-MS） and by elemental analyses. A plausible mechanism for such type of cyclization was proposed.

A New Poly Brominated Dibenzylphenol from Rhodomela confervoides

A new poly brominated dibenzylphenol named as rhodomevoidin was isolated from Rhodomela confervoides. Its structrue was elucidated as 3-bromo-4, 5-bis (2, 3-dibromo-4, 5- dihydroxybenzyl)pyrocatechol by spectroscopic methods including IR, HRFABMS, 1D and 2D NMR techniques.

A Green and Novel Method for the Synthesis of 4,4-Difluoro-3- oxo-2-（triphenylphosphoranylidene） 5-Lactones by Reformatsky Reaction

In the presence of In/CuCl, ethyl 4-bromo-4,4-difluoro-3-oxo-2-（triphenylphosphoranylidene）butanoate reacted with various aldehydes in aqueous medium at room temperature to give the a,a-difluorinated β-hydroxy carbonyl compounds. Furthermore, treating Reformatsky addition compounds with 1 equiv, of sodium hydroxide in the mixture of tetrahydrofuran and water afforded gem-difluoromethylenated 2-triphenylphosphoranylidene δ-lactones in excellent yields.

Competition of Aromatic Bromination and Nitration in Concentrated Sulfuric Acid

Composition of bromine and nitric acid in concentrated sulfuric acid is effective for bromination of strongly deactivated aromatic compounds and for nitration and bromination of moderately deactivated compounds in one stage. The question why brominating agent is more reactive than nitrating agent in relation to strongly deactivated aromatic compounds and is less reactive in relation to moderate deactivated ones is discussed.

Aromatic Bromination in Concentrated Nitric Acid

Action of bromine in concentrated nitric acid allows carrying out mono- and polybromination of moderately deactivated aromatic compounds. 4-Chloronitrobenzene and isophthalic acid turnes into 3-bromo-4-chloronitrobenzene and 5-bromoisophthalic acid at reaction with bromine in concentrated nitric acid at 20°C whereas in absence of bromine in the same conditions 4-chloro-1, 3-dinitrobenzene and 5-nitroisophthalic acid are formed accordingly. Presence of bromine in concentrated nitric acid changes nitrating capacity to brominating one. Terephthalic acid and phthalic anhydride at heating with bromine in concentrated nitric acid can be transformed to appropriating tetrabromo substituted compounds.