PECULIARITIES OF ISOCYANATES INTERACTION WITH HYDRAZINE DERIVATIVES

The results of studies on chemical transformations of organic and organosilicon isocyanates in their interaction with hydrazine derivatives have been summarized in this review. It is shown that hydrazine and its derivatives including organosilicon compounds reacting with organic isocyanates form corresponding semicarbazides readily enough. The reaction conditions that effect the composition, structure and yield of the resulting target products are presented. A significant difference in the interaction of trimethylsilyl isocyanate with organic and organosilicon derivatives of hydrazine is demonstrated. It is demonstrated that the reason for the impossibility to isolate trimethylsilyl derivatives of semicarbazide is their low hydrolytic stability, as well as high silylating ability. Peculiarities of the reaction of trimethylsilyl isocyanate and dimethylchloromethyl isocyanate silane with 1,1-dimethylhydrazine, its trimethylsilyl analog and isoniazid are given. Possible schemes for the formation of a previously unknown O-trimethylsilyl-1,1-dimethylhydrazinecarboximidoate are presented. The results of using carbofunctional organosilicon isocyanates in these processes are discussed. Basic trends in practical use of the prepared compounds as physiologically active preparations in polymer chemistry and agriculture are shown.

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The Use of Electrophilic Cyclization for the Preparation of Condensed Heterocycles

Synthesis ◽

10.1055/s-0040-1706036 ◽

2021 ◽

Author(s):

Mikhailo Slivka ◽

Mikhailo Onysko

Keyword(s):

Biological Effects ◽

Electrophilic Cyclization ◽

Chemical Transformations ◽

Cyclization Reactions ◽

Reaction Conditions ◽

Electrophilic Reaction ◽

Partially Saturated ◽

Current State ◽

Derivatives Of ◽

Condensed Heterocycles

AbstractCondensed heterocycles are well-known for their excellent biological effects and they are undeniably important compounds in organic chemistry. Electrophilic cyclization reactions are widely used for the synthesis of mono-heterocyclic compounds. This review highlights the utility of electrophilic cyclization reactions as an effective generic tool for the synthesis of various condensed heterocycles containing functional groups that are able to undergo further chemical transformations, such as nucleophilic substitution, elimination, re-cyclization, cleavage, etc. This review describes the reactions of unsaturated derivatives of different heterocycles with various electrophilic agents (halogens, arylsulfanyl chlorides, mineral acids) resulting in annulation of an additional partially saturated heterocycle. The electrophilic reaction conditions, plausible mechanisms and the use of such transformations in organic synthesis are also discussed. The review mainly focuses on research published since 2002 in order to establish the current state of the art in this area. 1 Introduction2 Electrophilic Cyclization Pathways Involving a Nitrogen Nucleophilic Center3 Electrophilic Cyclization Pathways Involving a Chalcogen Nucleophilic Center3.1 Sulfur Centers3.2 Oxygen Centers3.3 Selenium Centers4 Strategies and Mechanisms5 Conclusion

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Peculiarities of the reactions of a,b-unsaturated g-bromoketones with hydrazine derivatives

French-Ukrainian Journal of Chemistry ◽

10.17721/fujcv6i1p56-66 ◽

2018 ◽

Vol 6 (1) ◽

pp. 56-66 ◽

Cited By ~ 1

Author(s):

Lyudmyla Potikha

Keyword(s):

Hydrazine Hydrate ◽

Aliphatic Ketone ◽

Reaction Conditions ◽

Hydrazine Derivatives ◽

Michael Type Addition ◽

Derivatives Of ◽

Reaction Result ◽

Reaction Schemes

The reaction result of a,b-unsaturated g-bromoketones with hydrazines depends on the structure of the reagents. Reaction with hydrazine hydrate leads to the mixture of 3,5- di(R)pyridazine, 3,6-di(R)pyridazine and 2,4-di(R)-1H-pyrrol-1-amine derivatives. The formation of three types of products is due to the structure of the unsaturated aliphatic ketone. Two competing reaction schemes of ketones with hydrazines are considered, which include condensation or Michael-type addition in the first stage. The main products of the reactions of halogen-substituted derivatives of g-bromodipnone with arylhydrazines are 1,3,5-triaryl-1,6-dihydropyridazines, which easily form aromatic salts under reaction conditions (when heated in EtOH).

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New iodine derivatives of flavonol and isoflavone

Anais da Academia Brasileira de Ciências ◽

10.1590/s0001-37652009000100004 ◽

2009 ◽

Vol 81 (1) ◽

pp. 21-28 ◽

Cited By ~ 1

Author(s):

Mário G. de Carvalho ◽

Virginia C. da Silva ◽

Tânia M.S. da Silva ◽

Celso A. Camara ◽

Raimundo Braz-Filho

Keyword(s):

Mass Spectra ◽

Chemical Interaction ◽

2D Nmr ◽

Racemic Mixture ◽

Reactive Site ◽

Reaction Conditions ◽

Unsaturated Ketones ◽

Significant Difference ◽

Stereo Selectivity ◽

Derivatives Of

The reaction of the flavonol 3,7,3', 4'-tetra-O-methylquercetin (1) and of the isoflavone 7,4'-di-O-methylgenistein (2) with alkaline iodine in methanol afforded four new iodine derivatives: 8-iodo-5-hydroxy-3,7,3', 4'-tetramethoxy- flavone (1a) and 6-iodo-5-hydroxy-3,7,3', 4'-tetramethoxyflavone (1b) from 1; 2 afforded a mixture of two compounds, identified as a racemic mixture of (±)-trans-5-hydroxy-2,3,7,4'-tetramethoxy-8-iodo-isoflavanone (2a) and (±)-trans-5-hydroxy-2,3,7,4'-tetramethoxy-6,8-diiodo-isoflavanone (2b). The formation of these different products reveals a significant difference involving the chemical interaction between the reactive site of α, β-unsaturated ketones of flavonol and isoflavone under the tested reaction conditions (using I2/KOH/MeOH). Furthermore, the trans stereo selectivity is noteworthy in the nucleophylic addition of methanol at the isoflavone α, β-unsaturated system. The structures were identified on the basis of spectral data, mainly 1D and 2D NMR and mass spectra.

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Synthesis of polymeric derivatives of lactic acid by chemical transformations of polyacrylamide

International Journal of Pharmaceutical Research ◽

10.31838/ijpr/2020.12.01.395 ◽

2020 ◽

Vol 12 (01) ◽

Keyword(s):

Lactic Acid ◽

Chemical Transformations ◽

Derivatives Of

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Cleavage of the Epimines of 1,6-Anhydrohexoses with Fluoride Anion

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20052075 ◽

2005 ◽

Vol 70 (12) ◽

pp. 2075-2085 ◽

Cited By ~ 5

Author(s):

Jiří Kroutil ◽

Klára Jeništová

Keyword(s):

Fluoride Anion ◽

Ring Cleavage ◽

Protecting Group ◽

Reaction Conditions ◽

Aziridine Ring ◽

Cleavage Reactions ◽

Derivatives Of ◽

Fluoro Derivatives

Aziridine ring cleavage reactions of five N-nosylepimines (2-6) having D-talo, D-galacto, D-manno, and D-allo configurations with potassium hydrogendifluoride under various reaction conditions have been performed. The cleavage regioselectively afforded diaxial isomers of vicinal amino-fluoro derivatives of 1,6-anhydro-β-D-gluco- and mannopyranose 7-11 in 51-94% yields. Removal of 2-nitrobenzenesulfonyl protecting group with benzenethiol has been attempted in the case of compound 10.

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ChemInform Abstract: TRIMETHYLSILYL DERIVATIVES OF TITANIUM

Chemischer Informationsdienst ◽

10.1002/chin.197819245 ◽

1978 ◽

Vol 9 (19) ◽

Author(s):

G. A. RAZUVAEV ◽

V. N. LATYAEVA ◽

L. I. VYSHINSKAYA ◽

A. V. MALYSHEVA ◽

G. A. VASI'EVA

Keyword(s):

Trimethylsilyl Derivatives ◽

Derivatives Of

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Enzymatic synthesis and phosphorolysis of 4(2)-thioxo- and 6(5)-azapyrimidine nucleosides by E. coli nucleoside phosphorylases

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.12.254 ◽

2016 ◽

Vol 12 ◽

pp. 2588-2601 ◽

Cited By ~ 3

Author(s):

Vladimir A Stepchenko ◽

Anatoly I Miroshnikov ◽

Frank Seela ◽

Igor A Mikhailopulo

Keyword(s):

Purine Nucleoside Phosphorylase ◽

Reaction Conditions ◽

E Coli ◽

No Formation ◽

Structural Peculiarities ◽

Substrate Properties ◽

Nucleoside Phosphorylases ◽

Derivatives Of

The trans-2-deoxyribosylation of 4-thiouracil (4SUra) and 2-thiouracil (2SUra), as well as 6-azauracil, 6-azathymine and 6-aza-2-thiothymine was studied using dG and E. coli purine nucleoside phosphorylase (PNP) for the in situ generation of 2-deoxy-α-D-ribofuranose-1-phosphate (dRib-1P) followed by its coupling with the bases catalyzed by either E. coli thymidine (TP) or uridine (UP) phosphorylases. 4SUra revealed satisfactory substrate activity for UP and, unexpectedly, complete inertness for TP; no formation of 2’-deoxy-2-thiouridine (2SUd) was observed under analogous reaction conditions in the presence of UP and TP. On the contrary, 2SU, 2SUd, 4STd and 2STd are good substrates for both UP and TP; moreover, 2SU, 4STd and 2’-deoxy-5-azacytidine (Decitabine) are substrates for PNP and the phosphorolysis of the latter is reversible. Condensation of 2SUra and 5-azacytosine with dRib-1P (Ba salt) catalyzed by the accordant UP and PNP in Tris∙HCl buffer gave 2SUd and 2’-deoxy-5-azacytidine in 27% and 15% yields, respectively. 6-Azauracil and 6-azathymine showed good substrate properties for both TP and UP, whereas only TP recognizes 2-thio-6-azathymine as a substrate. 5-Phenyl and 5-tert-butyl derivatives of 6-azauracil and its 2-thioxo derivative were tested as substrates for UP and TP, and only 5-phenyl- and 5-tert-butyl-6-azauracils displayed very low substrate activity. The role of structural peculiarities and electronic properties in the substrate recognition by E. coli nucleoside phosphorylases is discussed.

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