Reaction of 2,4-Difunctional Esters of 5-tert-Butylfuran-3-carboxylic Acid with Nucleophilic Reagents

Ethyl 5-tert-butyl-4-(chloromethyl)-2-methylfuran-3-carboxylate was brominated with N-bromo-succinimide to obtain the corresponding 2-bromomethyl derivative. The latter is selectively phosphorylatedwith trimethyl, triethyl phosphites by the bromomethyl group. The resulting [4-(chloromethyl)furyl]methyl-phosphonates in the presence of secondary amines and sodium butanethiolate behave as alkylating agents,while sodium phenolate causes their decomposition. 4-Acetoxymethyl- and 4-phenoxymethyl derivatives of the starting product are also selectively brominated with N-bromosuccinimide by the 2-methyl group. The first of the 2-(bromomethyl)furans formed is smoothly phosphorylated with trimethyl phosphite, while the second one under the action of triethyl phosphite gives a mixture of phosphorylation and debromination products. In all the cases, an additional electron-acceptor group in position 4 of alkyl 2-(bromomethyl)-5-tert-butylfuran-3-carboxylate considerably accelerates the Arbuzov reaction.     

Reactions of Zinc Enolates of Substituted 1-Aryl-2,2-dibromobutanones with Alkyl Esters of 3-Oxo-3H-benzo[f]chromene-2-carboxylic Acid

Zinc enolates derived from substituted 1-aryl-2,2-dibromobutanones react with alkyl 3-oxo-3H-benzo[f]chromene-2-carboxylates to form alkyl 1-aroyl-1-ethyl-2-oxo-1,9c-dihydro-3-oxacyclopropa[c]phenanthrene-1a-carboxylate as a single geometric isomer.     

Reaction of Zinc Enolates of Alkyl Esters of Substituted 4-Bromo-3-Oxoalkanoic Acids with Aldehydes

Zinc enolates formed from ethyl 4-bromo-2,2,4-trimethyl-3-oxopentanoate react under the conditions of one- of two-stage synthesis with aliphatic, unsaturated, or aromatic aldehydes to form 6-R-2,2,4,4-tetramethyl-2,3,5,6-tetrahydropyran-2,4-diones. Zinc enolates obtained from ethyl 4-bromo-2,2-dimethyl-3-oxopentanoate, -hexanoate, and -2,2,5-trimethyl-3-oxohexanoate under the similar conditions react with aliphatic or aromatic aldehydes to give mainly 5-R¹-6-R²-3,3-dimethyl-2,3,5,6-tetrahydropyran-2,4-diones as E or Z isomers or their mixtures. Zinc enolates generated from the ethyl 4-bromo-2,2-diethyl- or 2-benzyl-2-ethyl-3-oxobutanoates react with aromatic aldehydes to give ethyl 5-R-2-R-2-ethyl-3-oxo-4-pentenoates as E isomers.     

Copper-Catalyzed Coupling Reaction of Secondary Alkyl 2-Pyridinesulfonates with Alkyl Lithium-Based Reagents

The Cu(OTf)₂-catalyzed alkyl–alkyl coupling reaction of a secondary substrate MeCH(OSO₂Py)CH₂CH₂C₆H₄(4-OMe) with a nBuLi-based reagent prepared by transmetalation with MgBr₂ ⋅ THF₃ in THF produced a coupling product in 74 % yield. The use of soluble MgBr₂ ⋅ THF₃ in THF was required for this reaction. This method was applied to sBuLi and Ph(CH₂)₄Li. In contrast, transmetalation of MeLi with soluble MgCl₂ ⋅ THF₂ in THF produced the Me reagent, which was reactive for the coupling reaction. The reaction proceeded with inversion of the stereogenic carbon. Furthermore, (S)-14-methyloctadecan-2-one, a sex pheromone produced by lichen moths, was synthesized.     

Reactions of Substituted 2,3,7-Triazabicyclo[3.3.0]oct-3-ene-4-carboxylic Acid Esters with Halogens

Substituted 2,3,7-triazabicyclo[3.3.0]oct-3-ene-4-carboxylic acid esters react with chlorine and bromine to give the corresponding 4-halo-2,3,7-triazabicyclo[3.3.0]oct-2-ene-4-carboxylates. Heating of the latter to 120°C under reduced pressure leads to elimination of nitrogen molecule and formation of 6-halo-3-azabicyclo[3.1.0]hexane-6-carboxylates.     

Reaction of Zinc Enolates Formed from 1-Aryl-2,2-dibromoalkanones and Zinc,with Substituted 2-Oxochromene-3-carbohydrazides

Zinc enolates formed from 1-aryl-2,2-dibromoalkanones and zinc react with N′-methyl-N′-phenyl- and N′-benzylidene-N-phenylhydrazides of 2-oxochromene-3-carboxylic acid to form the corresponding hydrazides of 1-alkyl-1-aroyl-2-oxo-1a,7b-dihydrocyclopropa[c]chromene-1a-carboxylic acid as a single geometric isomer.     

Reformatsky Reaction of Methyl α-Bromoisobutyrate with 2-Arylmethylidenemalonic Acid Derivatives

Reformatsky reagent obtained by treatment of methyl α-bromoisobutyrate with zinc reacts with dimethyl 2-arylmethylidenemalonates to give trimethyl 2-aryl-3-methylbutane-1,1,3-tricarboxylates. The reaction of the same compound with ethyl 3-aryl-2-(4-methylphenylcarbamoyl)acrylates yields cyclic products, ethyl 4-aryl-5,5-dimethyl-1-(4-methylphenyl)-2,6-dioxopiperidine-3-carboxylates. Treatment of the latter with morpholine and phenylhydrazine leads to the corresponding 4-aryl-5,5-dimethyl-1-(4-methylphenyl)-2,6-dioxopiperidine-3-carboxylic acid morpholides and phenylhydrazides. The products are formed as a single diastereoisomer.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 7, 2005, pp. 1034–1038.Original Russian Text Copyright © 2005 by Shchepin, Fotin.     

Reformatsky Reaction with N-Substituted 6-Bromo-2-oxochromene-3-carboxamides

Reformatsky reactions of ethyl -bromopropionate, methyl -bromobutyrate, and methyl -bromo-isobutyrate with N-substituted 6-bromo-2-oxochromene-3-carboxamides in the system diethyl ether–benzene– HMPA give N-benzyl-6-bromo-4-(1-alkoxycarbonylalkyl)-2-oxochroman-3-carboxamides, while in the system diethyl ether–benzene–HMPA–THF, 3-R¹-1-R²-1-R³-9-bromo-2,3,4,4a,5,10b-hexahydro-1H-chromeno[3,4-c]-pyridine-2,4,5-triones are obtained.     

Interaction of Nitromethane with Esters and Amides of 2-Oxo-2H-1-benzopyrane-3-carboxylic Acid

The reaction of esters as well as N,N-disubstituted amides of 2-oxo = 2H-1-benzopyran-3-carboxylic acid with nitromethane in the presence of potassium fluoride leads to the corresponding diesters and ester -amides of 2-carboxy-3-(2-hydroxyphenyl)-4-ni trobutyric acid (2a-m). The configuration and preferable conformation of the ester-amides are discussed.     

Synthesis of 4,5-Dichloroisothiazole-3-carboxylic Acid Amides and Esters

Previously unknown 4,5-dichloroisothiazole-3-carboxylic acid amides and esters were synthesized by reactions of 4,5-dichloroisothiazole-3-carbonyl chloride with ammonia, heterocyclic and aromatic amines, and functionally substituted alcohols and phenols.     

Reaction of Alkyl Sulfoxides and Phenylphosphinic Acid with Amines. Alternative Reagents for Secondary Amines N-Alkylation

Phenylphosphinic acid and dialkylsulfoxides are found to be alternative reagents for respectively the reducing reagent (formic acid) and the alkylating reagent (aldehyde) currently used for secondary amines N-alkylation. Primary amines do not react with this system, but phenylglycine is decarboxilated to benzylamine.     

Reaction of 3-Benzoyl-2,3-dibromopropionic Acid with Substituted ortho-Phenylenediamines

3-Benzoyl-2,3-dibromopropionic acid reacts with 4-substituted o-phenylenediamines to give 3-aryl-2-carboxymethylene-1,2-dihydroquinoxalines.     

Reaction of 1-Nitro-9,10-anthraquinone-2-carboxylic Acid with 2-Aminoethanol

1-Nitro-9,10-anthraquinone-2-carboxylic acid reacts with 2-aminoethanol to give 1-(2-hydroxy- ethylamino)-9,10-anthraquinone-2-carboxylic acid which undergoes intramolecular cyclization to 1,2,3,5,8,13- hexahydroanthra[1,2-e][1,4]oxazepine-5,8,13-trione on heating in acetic acid. Reactions of the cyclization product with amines result in cleavage of the seven-membered heteroring.     

Complexes of Lanthanide Nitrates with Alkyl Esters of Bromomethylenediphosphonic Acid

Complexes of lanthanide nitrates (La, Ce, Sm, Gd, Er, and Yb) with tetraethyl and tetraisopropyl esters of bromomethylenediphosphonic acid were prepared. The complexes were characterized by elemental analysis, IR spectroscopy, and, in some cases, NMR. The data confirm that diphosphonates coordinate with two P[dbnd]O groups, and there are no indications for the existence of noncoordinated P[dbnd]O groups. The structure of the complexes depends only on the ionic radius of the central metal atom and not on changes in the electronic or steric behavior of the ester groups. For the complexes of La, Ce, Sm, and Gd nitrates, the formula is LnL₂(NO₃)₃, and for Er and Yb nitrates it is Ln₂L₃(NO₃)₆ (Ln[dbnd]La, Ce, Sm, Gd, Er, Yb; L = diphosphonate).     

氨基酸衍生物催化的不对称Reformastky反应

首次使用侧链上带有配位基因的氨基酸组成的线二肽、环二肽及氨基酸酯作手性配体催化不对称的Reformatsky反应。考察了配体结构、反应底物结构以及反应条件等因素对反应产物ee值的影响。同其它两类配体相比,环肽具有更好的不对称催化效果,其中具有C2对称性的环肽3a效果最好,产物的ee值达到了64％。     

New Synthesis of Substituted Cyclopropanephosphonic Acid Esters

Abstract

Aminocyclopropane phosphonic acids are considered to be “transition state analogues” of aminocyclopropanecarboxylic acids and they may serve as enzyme inhibitors¹. We attempted to synthesise aminocyclopropane derivatives by a new route². Phosphonoacetic acid allylic esters were subjected to an intramolecular, radical cyclisation in the presence of iodine, solid potassium carbonate and phase transfer catalyst.     

Reaction with Azomethines or Azines of Reformatsky Reagents Prepared from Methyl 1-Bromocycloalkanoates and Zinc

Reformatsky reagents prepared from methyl 1-bromocycloalkanoates and zinc react with azomethines or azines to give 2,3-diaryl-2-azaspiro[3.5]nonan-1-ones, 2,3-diaryl-2-azaspiro[3.4]octan-1-ones or 2,2′ -bis(3-aryl-1-oxo-2-azaspiro[3.5]nonanes), respectively.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 4, 2005, pp. 629–631.Original Russian Text Copyright © 2005 by Kirillov, Shchepin.     

Functionally Substituted Amides and Esters of 3,4,4-Trichloro-3-butenoic Acid

Substituted amides and esters of 3,4,4-trichloro-3-butenoic acid were prepared by reactions of its chloride with appropriate amines and alcohols. Treatment of 3,4,4-trichloro-3-butenomorpholide and tert-butyl 3,4,4-trichloro-3-butenoate results in nucleophilic substitution of the internal chlorine atom with the morpholine residue, accompanied by prototropic allyl rearrangement.