Chlorination of 4-acetoxybenzoic acid and subsequent substitution with hydrosulfide

10.1039/sp766 ◽  
2014 ◽  
Author(s):  
Amol Jadhav ◽  
Manoj Uphade ◽  
Raju Thombal
Keyword(s):  
Subsequent Substitution

Direct formation and subsequent substitution of remote ketone-functionalized organocopper reagents

1991 ◽  
Vol 56 (15) ◽  
pp. 4744-4747 ◽  
Author(s):  
Greg W. Ebert ◽  
Walter R. Klein
Keyword(s):  
Direct Formation ◽  
Subsequent Substitution

Formation of organosilicon compounds 117:1 C-brominated 1,3,5-trisilacyclohexanes and their reactions with BuLi

2000 ◽  
Vol 78 (11) ◽  
pp. 1388-1395 ◽  
Author(s):  
G Fritz ◽  
M Keuthen ◽  
F Kirschner ◽  
E Matern ◽  
H Goesmann ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
Molecular Structures ◽  
Ring Closure ◽  
Organosilicon Compounds ◽  
Structure Investigation ◽  
X Ray ◽  
Nmr Data ◽  
High Yields ◽  
Subsequent Substitution ◽  
Preparative Route

The photobromination of 1,1,3,3,5,5-hexamethyl-1,3,5-trisilacyclohexane (1) almost exclusively attacks CH2 groups and results in 2,2-dibromo-trisilacyclohexane (2) as well as 2,2,4,4-tetrabromo-trisilacyclohexane (3) in high yields. Starting from a mixture of C-brominated trisilacyclohexanes the isomeric 2,2,9-tribromo-1,3,3,5,5,8,8,10,10,13,13-undecamethyl-1,3,5,8,10,13-hexasilabicyclo[7.2.2]tridec-6-yne (6) had been obtained in very low yield in an attempt to establish a preparative route to adamantanes with a C4Si6 skeleton, i.e., with C bridgeheads and SiR2 bridges. By ICl-cleavage of a Si—methyl bond in 2 and subsequent substitution with Br3CLi, the trisilacyclohexane 4 with functional groups in opposite positions of the ring can be obtained. Linking the step-by-step synthesized Cl-Me2Si-C=C-SiMe2-CH2-SiMe2-Ph to the CBr3 group of 4 results after HBr-cleavage of the Si—Ph bond in (ω-bromo-octynyl)-trisilacyclohexane (12). A ring closure of 12 would result in an isomeric hexasila bicyclo[7.2.2]tridec-6-yne. The compounds were characterized by 1H, 13C, and 29Si NMR spectra. Additionally, the molecular structures of 4 and 6 were confirmed by X-ray single crystal investigations.Key words: 1,1,3,3,5,5-hexamethyl-1,3,5-trisilacyclohexane, bromination, 2,2,9-tribromo-1,3,3,5,5,8,8,10,10,13,13-undecamethyl-1,3,5,8,10,13-hexasilabicyclo[7.2.2]tridec-6-yne, carbosilane synthesis, NMR data, crystal structure investigation.

scholarly journals Preparation of the Key Dolutegravir Intermediate via MgBr2-Promoted Cyclization

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2850
Author(s):  
Jiahui Kong ◽  
Haijian Xia ◽  
Renbao He ◽  
Hao Chen ◽  
Yongping Yu
Keyword(s):  
Intramolecular Cyclization ◽  
Oxalyl Chloride ◽  
Dimethyl Acetal ◽  
Selective Hydrolysis ◽  
Excellent Yield ◽  
Novel Approach ◽  
Hydrolysis Of ◽  
Subsequent Substitution

A novel approach for synthesizing the key dolutegravir intermediate is described via MgBr2-promoted intramolecular cyclization. Condensation of commercially available methyl oxalyl chloride and ethyl 3-(N,N-dimethylamino)acrylate afforded the vinylogous amide in an excellent yield. Subsequent substitution by aminoacetaldehyde dimethyl acetal and methyl bromoacetate gave rise to the expected precursor for cyclization, which was promoted by MgBr2 to highly selectively convert into pyridinone diester. The key dolutegravir intermediate was finally prepared by the selective hydrolysis of the corresponding diester via LiOH.

Analysis of upstream activation of thevnfHpromoter ofAzotobacter vinelandii

1998 ◽  
Vol 44 (5) ◽  
pp. 405-415 ◽  
Author(s):  
Umesh K Bageshwar ◽  
Ramesh Raina ◽  
Nirupam Roy Choudhury ◽  
H K Das
Keyword(s):  
Azotobacter Vinelandii ◽  
Dna Bending ◽  
Polyacrylamide Gel Electrophoresis ◽  
Upstream Region ◽  
Curved Dna ◽  
Low Concentrations ◽  
The Face ◽  
Dna Fragment ◽  
Ofazotobacter Vinelandii ◽  
Subsequent Substitution

BAL-31 deletion products of the DNA fragment containing the vnfH promoter and upstream region, when cloned in a transcriptional fusion vector and analyzed for vnfH expression in Azotobacter vinelandii, revealed that the upstream activator sequence of the vnfH promoter lies about 140 nucleotides upstream of the promoter. Subsequent substitution and deletion analysis by oligonucleotide-directed mutagenesis in the upstream region of the vnfH promoter showed that sequences 5'-GTACCATGCGGAAC-3' and 5'-GTACCTGCGGGTAC-3', located 170 and 140 nucleotides upstream of the vnfH promoter, respectively, are both required for vnfH expression. Addition of four nucleotides in the intervening sequence between the vnfH promoter and the putative VnfA (analog of NifA of the conventional molybdenum-dependent nitrogen-fixation pathway) binding site resulted in a drastic reduction of expression from the vnfH promoter in Azotobacter vinelandii, where as addition of 10 nucleotides in the intervening sequence did not affect the expression. Therefore, the face of the helix-dependent contact appeared to be important. DNA bending seemed to play a crucial role in expression from vnfH promoter. The intervening sequence exhibited characteristics of sequence-dependent intrinsically curved DNA, as shown by anomalous low gel mobility with polyacrylamide gel electrophoresis, electron microscopy, and computer simulated curvature analysis. Distamycin at very low concentrations significantly reduced the anomaly in electrophoretic mobility of the intervening DNA sequence.Key words: Azotobacter vinelandii, vnfA, vnfH, promoter-lacZ fusion, DNA bending.

A kinetic study of the reactions of dimethyl sulfide bridged tetramethylplatinum(II) and octamethylplatinum(IV) complexes with dimethyl sulfide and bidentate ligands

1998 ◽  
Vol 76 (1) ◽  
pp. 62-70
Author(s):  
Katsuyuki Nakayama ◽  
Yuichi Kondo ◽  
Koji Ishihara
Keyword(s):  
High Pressure ◽  
Reaction Mechanism ◽  
Dimethyl Sulfide ◽  
Activation Parameters ◽  
Bidentate Ligand ◽  
Direct Reaction ◽  
Bidentate Ligands ◽  
High Pressure Kinetics ◽  
Subsequent Substitution ◽  
Rapid Conversion

Kinetics for the reactions of [1] [PtIV2Me8 (μ - SMe2 )2] + 2 Me 2S kf<-->kd 2[PtIVMe4 (SMe2 ) 2] [2] [PtII2Me4 (μ - SMe2 )2] + 2 Me 2S kf--> 2[PtIIMe2(SMe2 ) 2 ] and [3] [PtIV2Me8 (μ - SMe2 ) 2 ] + 2NN --> 2 [PtIVMe4 (NN)]+2Me2S where NN = bipy or 4,4'-Me2-bipy, have been studied at various temperatures and pressures. Reaction [3] was shown to consist of the rapid conversion of the dimer to a monomer and the much slower subsequent substitution of the dimethyl sulfide with bidentate ligand NN: [PtIV2Me8 (μ - SMe2 )2] + 2 Me 2S <--> 2 [PtIVMe4 (SMe2 ) 2 ] and [PtIVMe4(SMe2)2] + NN --> [PtIVMe4(NN)] + 2 Me2S The rate constants and activation parameters for the reactions are as follows: kf = 3.16 ± 0.06 M-1 s-1 (25°C), Δ H doubledaggerf= 51.8 ± 1.7 kJ mol-1, Δ S doubledaggerf= -61.0 ± 5.8 J mol-1 K-1, kd = 1.18 ± 0.22 M-1 s-1 (25°C), Δ H doubledaggerd= 65 ± 22 kJ mol-1, Δ S doubledaggerd= -26 ± 73 J mol-1 K-1 for reaction [1] in n-hexane; kf = 6.68 ± 0.06 M-1 s-1 (25°C), Δ H doubledaggerf= 58.0 ± 3.1 kJ mol-1, Δ S doubledaggerf= -34.5 ± 10.5 J mol-1 K-1, Δ V doubledaggerf= -10.7 ± 1.3 cm3 mol-1 for reaction [2] in dichloromethane; k2 = (7.09 ± 1.89) x 10-4 M-1 s-1, Δ H doubledagger2= 95 ± 21 kJ mol-1, and Δ S doubledagger2= 18 ± 70 J mol-1 K-1, Δ V doubledagger2= 9 ± 9 cm3 mol-1 for reaction [3] with bipy, and k1 = (1.10 ± 0.10) x 10-2 s-1, k3/k-1 = (4.33 ± 0.30) x 10-2, and k2 = (6.09 ± 1.35) x 10-4 M-1 s-1 for reaction [3] with 4,4'-Me2-bipy. It was shown that reactions [1] and [2] proceed nucleophilically without any intermediates, and reaction [3] proceeds through a mainly k2 path for NN = bipy and through both k1 and k2 paths for NN = 4,4'-Me2-bipy, without appreciable participation of the direct reaction between the dimer and NN as shown by the following reaction scheme.Key words: octamethylplatinum(IV) dimer, tetramethylplatinum(II) dimer, reaction mechanism, high-pressure kinetics.

Synthese und fungizide Eigenschaften von Phosphorsäureethylesterdiamiden/Synthesis and Fungicidal Properties of Phosphorodiamidates

1985 ◽  
Vol 40 (2) ◽  
pp. 298-304 ◽  
Author(s):  
Rainer Schaller ◽  
Hilmar Mildenberger ◽  
Burkhard Sachse
Keyword(s):  
Broad Spectrum ◽  
Fungicidal Activity ◽  
Morpholine Derivatives ◽  
Subsequent Substitution

Abstract Secundary amines - especially 2-aryloxyethyl-n-propylamines and 4-arylpiperazines were treated with ethyldichlorophosphate yielding ethylchlorophosphamides. Subsequent substitution of the chloroatom by morpholine derivatives, imidazole or triazole formed new ethylphosphorodiamidates with a broad-spectrum-fungicidal activity. Experimental details as well as the fungicidal properties are reported.

Die (1-Cyclohepta-2,4,6-trienyl)thiolato-verbrüuckten Zweikernkomplexe – Mn2(CO)8(μ2-SC7H7)2 und Mn2(CO)6(C≡NtBu)2(μ2-SC7H7)2 / The (1-Cyclohepta-2,4,6-trienyl)thiolato-Bridged Dinuclear Complexes Mn2(CO)8(μ2-SC7H7)2 and Mn2(CO)6(C≡NtBu)2(μ2-SC7H7)2

2004 ◽  
Vol 59 (6) ◽  
pp. 673-680 ◽  
Author(s):  
Max Herberhold ◽  
Wolfgang Milius ◽  
Jinnan Liu
Keyword(s):  
Structural Parameters ◽  
Molecular Structures ◽  
Dinuclear Complexes ◽  
X Ray ◽  
Carbonyl Ligands ◽  
Tert Butyl ◽  
X Ray Crystallography ◽  
Centrosymmetric Dimers ◽  
Subsequent Substitution

The reactions of either Mn2(CO)10 (under irradiation) or Mn(CO)5X (X = Cl, Br) with di(1-cyclohepta-2,4,6-trienyl) sulfide, S(C7H7)2 (1), led to the organothiolato-bridged dimer [Mn(CO)4(μ2-SC7H7)]2 (2) in addition to ditropyl, (C7H7)2. Subsequent substitution of two carbonyl ligands in 2 for tert-butyl isocyanide gave [Mn(CO)3(C≡NtBu)(μ2-SC7H7)]2 (3). The molecular structures of the centrosymmetric dimers 2 and 3 have been determined by X-Ray crystallography. Both 2 and 3 contain a planar Mn2S2 core with the 1-cyclohepta-2,4,6-trienyl substituents in anti-position. The structural parameters of dinuclear carbonylmanganese complexes containing organothiolato or thioether bridges are discussed.

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