Preparation of new reactive methylene monomers

Acryloylacetone, methacryloylacetone, and related monomers have been synthesized by using cyclopentadiene as a blocking agent during the Claisen condensation.     

Reactions of some diazoazoles with reactive methylene and other groups

Reactions of some heteroaromatic diazo compounds with 1,3-dicarbonyl compounds, amines and thiophenol to give bi- and tricyclic heterocycles are studied. Decomposition of heterocyclic diazo compounds, triazenes and related compounds are investigated.     

Reaction of tetrachloropyrazine with active methylene compounds

When tetrachloropyrazine was allowed to react with the anions formed from diethyl malonate and malonitrile, the normal alkylation took place. When the anions from ethyl acetoacetate and N,N-diethylacetoacetamide were used, alkylation was followed by enolization and ring formation to give furo [2,3-b] pyrazines. The structure proof and reaction of the furo [2,3-b] pyrazines are discussed.     

Photoelectron spectra of organic compounds—VI : Exocyclic methylene compounds

The photoelectron spectra of methylene and dimethylene derivatives of bridged and unbridged cyclohexane and cyclohexene were recorded and interpreted on the basis of an LCBO model. The conjugative interaction is found to be appreciably smaller for exocyclic cis-dienes than for the corresponding endocyclic cis-dienes, whereas the homoconjugative interaction between exocyclic and endocyclic double bonds and between two endocyclic double bonds is about the same.     

The reactions of some bromo-derivatives of compounds having reactive methylene groups with thioureas,and of some resultant thiouronium salts with base

Whereas α-bromocarbonyl compounds react with thiourea to give thiazole derivatives, bromomalononitrile and bromobis(phenylsulphonyl)methane underwent protodebromination. With N,N,N',N'-tetramethylthiourea many of the bromo-compounds gave thiouronium salts but protodebromination sometimes supervened. N,N'-Disubstituted thioureas provided examples of salt formation, protodebromination and cyclisation reactions. The only thiouronium salt to provide an ylide on treatment with base was the S- [bis(phenylsulphonyl)methyl]-N,N,N',N'-tetramethythiouronium bromide. N,N'-Disubstituted salts gave isothioureas rather than ylides. Thiouronium dicyanomethylide underwent cyclisation rather than a Wittig reaction when heated with p-nitrobenzaldehyde, and the aldehyde condensed with the resultant 2-aminothiazole.     

Acylaminoacetyl derivatives of active methylene compounds. 4

Meldrum's acid has been found to be effectively acylated using the imidazolides of N-protected glycines, X-NHCH₂COOH (X = -COPh, -COMe, -Z, -Boc, -COOMe and -COOEt). The corresponding C-acylation compounds were isolated in high yields and were readily converted to the N-protected tetramic acids. It was shown by pmr spectroscopy that these acids exist as the enol tautomers in DMSO-d₆ solution, whereas in deuteriochloroform solution both the enol and keto tautomers can be observed.     

Reaction of thiopyrylium ion with active methylene compounds

The reaction of 2,4,6-triphenylthiopyrylium ion with several active methylene compounds in the presence of base has been found to yield 2,4,6-triphenylbenzene derivatives. In the case of the reaction of 2,4,6-triphenylthiopyrylium fluoroborate with nitromethane, an alkali treatment gave 2,4,6-triphenylnitrobenzene, and an acid treatment afforded 2,4,6-triphenylbenzene, respectively. From these results, the reaction behaviour of the thiopyrylium ion has been discussed.     

Reaction of 3-azidoisoxazoles with active methylene compounds

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Introduction of functionalized substituents into active methylene compounds

Condensation of active methylene compounds with variously functionalized carbon two unit Michael acceptors ($\text{1}$–$\text{5}$) afforded the corresponding adducts, respectively. Reaction of such Michael adducts with NBS to afford the vinyl ($\text{15}$, $\text{16}$, and $\text{17}$) and ethynyl ($\text{21}$) bromides will also be described.     

Carbon-carbon bond formation from ethyl cyanoformate and active methylene compounds

A new methodology which leads to α,β-unsaturated α-amino acids has been developed through a carbon-carbon forming reaction using ethyl cyanoformate and active methylene compounds in the presence of zinc chloride and triethyl amine.     

Reaction of 1-alkylthioisoquinolinium salts with active methylene compounds

2-Alkyl-1-alkylthioisoquinolinium salts were readily prepared from 2-alkyl-1(2H)-isoquinolones via 2-alkyl1(2H)-thioisoquinolones in two steps. Under mild conditions, the reaction of 2-alkyl-1-alkylthioisoquinolinium salts with active methylene compounds in the presence of sodium hydride afforded 2-alkyl-1-(substituted methylene)iso-quinolines in good yields. Pyrrolo[2,1-a]isoquinolines were synthesized by the cyclization of 2-benzyl-1-(substituted methylene)isoquinolines using acetic anhydride.     

Reactions of quaternized imidazo-quinazoline and-pyridopyrimidine with active methylene compounds

Summary Syntheses of 1-methylimidazo[1,2-c]quinazolinium iodide (3) and 1-methylimidazo[2,1-f]pyrido[3,2-d]pyrimidinium iodide (4) are described. These tricyclic compounds react with nucleophiles derived from active methylene compounds to give the corresponding open-chain enamines.

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Reaktionen von quaternisierten Imidazo-Chinazolinen und -Pyridopyrimidinen mit Verbindungen mit reaktiven Methylengruppen

Zusammenfassung Synthesen von 1-Methylimidazo[1,2-c]chinazoliniumjodid (3) und 1-Methylimidazo[2,1-f]pyrido[3,2-d]pyrimidiniumjodid (4) werden beschrieben. Diese tricyclischen Verbindungen reagieren mit einigen Carbanionen aus Verbindungen mit reaktiven Methylengruppen, wobei die offenkettigen Enamine entstehen.

     

Indium-catalyzed addition of active methylene compounds to 1-alkynes

An active methylene compound adds to a 1-alkyne in high to quantitative yield upon heating in the presence of 0.05-5 mol % of In(OTf)3 to give an alpha-alkenylated carbonyl compound.     

Synthesis of highly reactive organosulfur compounds

Application of novel bowl‐type and dendrimer‐type steric protection groups to the first synthesis of stable aromatic S‐nitrosothiols is described. These compounds showed remarkable thermal stability whereas they easily reacted with appropriate reagents. X‐ray crystallographic analysis established their structures, where the C S N O linkage adopts only the syn conformation. Synthesis of a stable sulfenic acid by taking advantage of the bowl‐type substituent is also delineated. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:414–418, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10068     

有机磷化合物的研究IX.某些具有活泼亚甲基化合物的碳磷酰化反应

The formation of P -- C bond is one of the important problems in synthetic organophosphorous chemistry. This paper describes the study of the formation of P -- C linkage via phosphorylation of carbon atom containing active hydrogen. p-Substituted phenylacetonitrile possessing an active methylene group undergoes stepwise C -- phosphorylation smoothly with diethyl phosphoryl chloride in the presence of naphthalene-sodium. Phosphonyl chloride reacts analogously. Being a deprotonizing agent naphthalene-sodium is distinguished by its availability, effectiveness and mild reaction conditions. The presence of an electron-withdrawing group in the benzene ring reduces the yield of phosphorylation seriously. The chemical shift of ^3^1P NMR of the resulted α-cyano-benzylphosphonates (1) correlates linearly with the Hammett \s\ constants of the substituents. As indicated by ^1H NMR studies the protons in the ester ethyl groups are magnetically nonequivalent. Compound 1 can be alkylated with alkyl halide or condensed with aromatic aldehyde by Hornor-Wittig type reaction due to the presence of active hydrogen atom. The structure-reactivity studies of diethyl phosphoryl chloride on reacting with various β- and β-diketones and β-keto esters (5) as regiospecific reaction were reported. The influences of metal ions in the enolates on the reactivity of the latter were examined and discussed. Only vinyl phosphates with predominantly Z configuration have been isolated exclusively. The C atom with an active hydrogen in the β-diketones investigated is inert to phosphorylation. These experimental results are well supported by reaction selectivity in terms of Eqo/Ecoc based on EHMO calculation.