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Search for "hydrazines" in Full Text gives 59 result(s) in Beilstein Journal of Organic Chemistry.
Chemo-enzymatic modification of poly-N-acetyllactosamine (LacNAc) oligomers and N,N-diacetyllactosamine (LacDiNAc) based on galactose oxidase treatment
Beilstein J. Org. Chem. 2012, 8, 712–725, doi:10.3762/bjoc.8.80
- reduced with Na[BH3(CN)] to the corresponding hydrazines (15a–c and 16a). B: Elongation of biotinylated LacNAc (15a) and biotinylated tetrasaccharide (15b) by β3-N-acetylglucosaminyltransferase (β3GlcNAc-transferase) leads to an internally modified trisaccharide 16a as the enzymatic elongation of the
Synthesis of oleophilic electron-rich phenylhydrazines
Beilstein J. Org. Chem. 2012, 8, 275–282, doi:10.3762/bjoc.8.29
- increases its stability in the reaction medium. The hydrazines were isolated in 60–86% yields and purities >90%. The hydrazides 2 were obtained in 43–71% yields from aryl bromides 5, which were lithiated with t-BuLi and subsequently reacted with di-tert-butyl azodicarboxylate (DTBAD). Keywords
- deprotection of Boc-substituted hydrazines (Scheme 2), hydrazides 2, expecting that the reaction could be performed under fully homogenous conditions. Analysis of the reaction mechanism for the deprotection of 2 under acidic conditions shows that removal of the Boc group generates t-Bu+, which reacts with the
- be optimum; the purity of the hydrazine decreased with increasing reaction times. By using this protocol, hydrazines 1 were isolated as viscous oils in purities >90% and yields of 60–86%, according to 1H NMR analysis with 1,4-dimethoxybenzene as the internal standard (Scheme 3). Attempts at the
Derivatives of phenyl tribromomethyl sulfone as novel compounds with potential pesticidal activity
Beilstein J. Org. Chem. 2012, 8, 259–265, doi:10.3762/bjoc.8.27
- ammonia, amines, hydrazines and phenolates to give 2-nitroaniline, 2-nitrophenylhydrazine and diphenyl ether derivatives. Reduction of the nitro group of 4-tribromomethylsulfonyl-2-nitroaniline yielded the corresponding o-phenylenediamine substrate for preparation of structurally varied benzimidazoles
Efficient synthesis of 1,3-diaryl-4-halo-1H-pyrazoles from 3-arylsydnones and 2-aryl-1,1-dihalo-1-alkenes
Beilstein J. Org. Chem. 2011, 7, 1656–1662, doi:10.3762/bjoc.7.195
- based on the condensation of hydrazines with 1,3-dicarbonyl compounds or their equivalents. However, the 1,3-dipolar cycloaddition offers a more convenient synthetic route. Sydnones are easily accessible aromatic compounds and versatile synthetic intermediates. They can be used as unusual, alternative
Amines as key building blocks in Pd-assisted multicomponent processes
Beilstein J. Org. Chem. 2011, 7, 1387–1406, doi:10.3762/bjoc.7.163
- different approach to α,β-alkynyl ketone derivatives as pyrazole precursors. They established a four-component domino process combining various organic halides, terminal alkynes, hydrazines, and carbon monoxide at room temperature. In this case, all components are mixed at the very beginning of the process
- the intermediacy of α,β-alkynyl ketones in the four-component process could not be confirmed (TLC). In addition, their reaction with hydrazines was shown to be ineffective under the present solvent system in the presence or absence of palladium catalyst. This may suggest that if α,β-alkynyl ketones
- (after removal of excess acrylic acid) with the aid of an oligomeric alkyl carbodiimide 44 (Scheme 19) [19]. Interestingly, Willis and coworkers have shown that aryl N-aminosulfonamides may be accessed by three-component coupling of aryl iodides, hydrazines, and DABCO·(SO2)2 as a convenient source of
Continuous gas/liquid–liquid/liquid flow synthesis of 4-fluoropyrazole derivatives by selective direct fluorination
Beilstein J. Org. Chem. 2011, 7, 1048–1054, doi:10.3762/bjoc.7.120
- -diketones and hydrazines [23]. However, the synthetic methodology for the preparation of the corresponding fluoropyrazole derivatives has not been developed to any great extent despite the potential use of such systems in life science applications. Recently, we explored direct fluorination of various
Recent advances in the gold-catalyzed additions to C–C multiple bonds
Beilstein J. Org. Chem. 2011, 7, 897–936, doi:10.3762/bjoc.7.103
- application of [(R)-xylyl-binap-(AuOPNB)2] 383 in gold-catalyzed hydroaminations and hydroalkoxylations of allenes with hydroxylamines and hydrazines, which gave ee values of up to 99% [178]. Whereas chiral biarylphosphinegold(I) complexes are suitable catalysts for the enantioselective addition of nitrogen
Gold-catalyzed propargylic substitutions: Scope and synthetic developments
Beilstein J. Org. Chem. 2011, 7, 866–877, doi:10.3762/bjoc.7.99
- substitution would be followed by activation of the triple bond and addition of the remaining nucleophilic group to the alkyne (Scheme 11) [63]. Whereas no reaction occurred with bis-protected hydrazines, unexpected reactions occurred with protected (P = Cbz, PhSO2) hydroxylamines (Scheme 12). In model
Approaches towards the synthesis of 5-aminopyrazoles
Beilstein J. Org. Chem. 2011, 7, 179–197, doi:10.3762/bjoc.7.25
- involve the reactions of β-ketonitriles, malononitrile, alkylidenemalononitriles and their derivatives with hydrazines, as well as some novel miscellaneous methods. Keywords: alkylidenemalononitriles; 5-aminopyrazoles; hydrazines; β-ketonitriles; malononitriles; Review The 5-aminopyrazole system
- methods have recently appeared. Some of the important methods are outlined below. 1. Reaction of β-ketonitriles with hydrazines The most versatile method available for the synthesis of 5-aminopyrazoles involves the condensation of β-ketonitriles with hydrazines. β-Ketonitriles 1 react smoothly with
- hydrazines to yield 5-aminopyrazoles 3 [19][20][21][22][23][24][25][26][27][28]. The reaction apparently involves the nucleophilic attack of the terminal nitrogen of the hydrazine on the carbonyl carbon with the formation of hydrazones 2, which subsequently undergo cyclization by the attack of the other
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