Pyrrole-2-ones

Ethoxypyrrolin-5-one l-Pyrrolin-5-one, 2-ethoxy- (8) 2H-Pyrrol-2-one, 5-ethoxy-3,4-dihydro- (9) (29473-56-1) tert-Butyl N-(l-ethoxycyclopropyl)carbamate Cyclopropanecar-bamic acid, 1-ethoxy-, tert-butyl ester (8) Carbamic acid, (1-ethoxycyclopropyl)-, 1,1-dimethylethyl ester (9) (28750-48-3 41879-49-6)... 

Electron Transfer Type of Dehydrogenase Sensors To fabricate an enzyme sensor for fructose, we found that a molecular interface of polypyrrole was not sufficient to realize high sensitivity and stability. We thus incorporated mediators (ferricyanide and ferrocene) in the enzyme-interface for the effective and the most sensitive detection of fructose in two different ways (l) two step method first, a monolayer FDH was electrochemically adsorbed on the electrode surface by electrostatic interaction, then entrapment of mediator and electro-polymerization of pyrrole in thin membrane was simultaneously performed in a separate solution containing mediator and pyrrole, (2) one-step method co-immobilization of mediator and enzyme and polymerization of pyrrole was simultaneously done in a solution containing enzyme enzyme, mediator and pyrrole as illustrated in Fig.22. 

Polymerization (76MI11100) of the maleimide isomer 5-(l-adamantyloxy)-2//-pyrrol-2-one (11) allows incorporation (Scheme 6) of the 4-pyrrolin-2-one ring system into a polymeric framework. In analogy with model compounds, polymers and copolymers containing the structural unit (12) undergo photochemical rearrangement to the isocyanate structure (13). Thermolysis, on the other hand, produces poly(maleimides) (14). 

Pyrrol-2-one (71) has been studied under matrix isolation conditions (95JPC15870). It is converted photochemically into acetylene, hydrogen cyanide, and carbon monoxide. 

As another important mechanistic type, fragmentation into at least three products that are formed more or less simultaneously has to be mentioned. Such [5 - 2 + 2 + 1] reactions were encountered in 2-pyrrolidinones (65, 67), certain pyrazolidine derivatives (68, 72, 73), l,2,4-triazolidine-3-ones (69) and l,2,4-triazolidine-3,5-diones (70), 2//-pyrrol-2-ones (71), 1,3-dithiolane 1-oxides (78), 1,2,3,4-thiatriazoles (74), 1,2,4-oxadiazolines (75), and in several rings containing sulfur in an oxidized state (76-79,82). Most of these molecules have an exocyclic double bond. 

Diimino-thietane-2-carboxylic acid derivatives has been detected as an intermediate in synthesis of 4-amino-5-thioxo-l,5-dihydro-pyrrol-2-ones from ethyl mercaptoacetate and oxalodiimidoyl dichloride <2006JOC2332> (Scheme 29). 

Photocycloisomerization of Boc-protected 5-alkenyl-2,5-dihydro-l H-pyrrol-2-ones. Helvetica Chimica Acta, 86, 515-521. 

An interesting and truly catalytic cycloisomerization reaction of a-allenic amides was also reported recently which, however, afforded mixtures of 2-(5//)-furanylidenamines and l,5-dihydro-2//-pyrrol-2-ones in most cases.339 339a... 

Simple pyrroles frequently give complex breakdown products. Oxidation with oxygen (UV-irradiation, a photosensitizer, or an radical initiator) produces hydroxypyrrolones <1991JOC6942, 1999TL4519, 2002TA601>. For example, pyrrole 152 (30 C) leads to 5-hydroxy-l,5-dihydro-27/-pyrrol-2-one 153 <2003T8499>. 

Oxidation of the pyrrole 886 mainly gives the pyrrol-2-one 887 (Equation 217) <2004TA259>. 

The substituted pyrrole-2-carbaldehydes 888 and the 5-(17/-pyrrol-2-ylmethyl)-l//-pyrrole-2-carbaldehydes 891 are oxidized by hydrogen peroxide under mild conditions to give pyrrol-2-ones 889, 890 and 892 (Equations 218... 

Acidic hydrolysis or methanolysis of 5-(l-ethoxyethoxy)-l//-pyrroles 1403, assembled from lithiated l-(l-ethoxy-ethoxy)-2-heptyne 1402 and isothiocyanates in one-pot (Scheme 269), leads to 2-hydroxypyrroles 1404 that, unlike the 3-hydroxy-2-(alkylsulfanyl)-l//-pyrroles 1400, exist exclusively in the form of the tautomeric l,5-dihydro-2//-pyrrol-2-ones 1405 (IR and NMR data). An unprecedented inertness of W-(2-vinyloxy)ethyl group under conditions of acidic hydrolysis (dioxane/H20, HCl, 0°C, 5min) was revealed <2002RJ0907>. 

Amidines 9 with an appropriate ortho-carbonyl substituent, which are obtained from the respective ortho-carbonyl aniline derivatives and 0-ethyl succinimide (5-ethoxy-4,5-dihydro-3//-pyrrol-2-one), are cyclized with sodium in alcohol to quinazolin-4(3// )-ones 10a and quinazolines 10b with a 2-[(alkoxycarbonyl)ethyl] substituent at C2. The reaction can also be carried out starting from anthranilates or 2-aminophenyl ketones as a simple one-pot synthesis. ... 

Alkylidenecarbenes 126 give pyrrol-2-ones via intramolecular C—H insertion. As a synthetic method, the reaction is best suited for substrates in which the nitrogen of amides 127 is symmetrically substituted (86JOC3656). 

It has been reported that [1+ 4]-cycloaddition between alkyl isocyanides and 3-benzylidene-2,4-pentadione followed by tautomerisation of the resulting iminolac-tone gives the /V- a 1 k y 1 - 2 - a m i n o fu r a n s 71 (R = cyclohexyl, Bu, PhCH2) (Scheme 14) (97MC697). However, subsequent studies have shown that the isolated products are the pyrrol-2-ones 72, which are probably formed by oxidation of the intermediate 2-aminofurans 71 (04TL1413) (see also Section Il.C.l.a). 

Cyclopropyl Isocyanates from 3,4-Dihydro-2 f-pyrrol-2-ones... 

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