Nitriles esters

Formal oxidation of pyrrolidine to the succinimide stage affords a series of compounds used as anticonvulsant agents for treatment of seizures in petit mal epilepsy. Knoevnagel condensation of benzaldehyde with ethyl cyanoacetate affords the unsaturated ester, 9. Conjugate addition of cyanide ion leads to the di-nitrile ester (10). Hydrolysis in mineral acid affords the succinic acid (11), presumably by decarboxylation of the intermediate tricarboxyllie acid. Lactamization with methylamine gives phensuximide (12). ... 

It has been reported that an allylic C-Si bond can be cleaved by tetrabutylammonium fluoride to give an anionic allylic species, which chemoselectively adds to carbonyl compounds (nitriles, esters, and epoxides failed) to form homoallylsilyloxy compounds13. 

The catalytic conditions (aqueous concentrated sodium hydroxide and tetraalkylammonium catalyst) are very useful in generating dihalo-carbenes from the corresponding haloforms. Dichlorocarbene thus generated reacts with alkenes to give high yields of dichlorocyclopropane derivatives,16 even in cases where other methods have failed,17 and with some hydrocarbons to yield dicholromethyl derivatives.18 Similar conditions are suited for the formation and reactions of dibromocar-benc,19 bromofluoro- and chlorofluorocarbene,20 and chlorothiophenoxy carbene,21 as well as the Michael addition of trichloromethyl carbanion to unsaturated nitriles, esters, and sulfones.22... 

Rovis and co-workers have also shown that pre-catalyst 129 is competent with a wide range of Michael acceptors including oc,P-unsaturated aldehydes, amides, nitriles, esters, thioesters, vinylphosphonates and vinylphosphine oxides (Scheme 12.25) [58,60],... 

Formazans are stable in alkaline solution. Alkaline hydrolysis of functionalities on formazans such as nitriles, esters, and amides leads to the acids (Section 7.3.1.1). The case of 3-nitroformazans (198) is unique. Reaction with hydroxide ion gives 3-hydroxy formazan (199) which can be readily oxidized to the tetrazolium betaine. In the presence of hydrosulfide, a reduction of the nitro group takes place giving 3-aminoformazan (200) with traces of the 3-mercaptoformazan (201), which by contrast is the main product when ammonium polysulfide is used (Scheme 30).45,346... 

The addition-elimination adducts (143)-(145) are also useful precursors to imidazo[4,5-b]pyridines. Thus, the malonate derived products (143) on treatment with hot ethanolic HC1 [92JCS(P1)2789] or hot ethanolic triethylamine (78H241) gave the imidazo[4,5-b]pyridones (157). The dinitrile derivatives (144) gave the ortho amino nitriles (158) by treatment with hot methanolic sodium hydroxide solution and the nitrile esters (145)... 

Toward the Reduction of Simple Ketones, Nitriles, Esters and Aromatics with Monodentate Phosphine Systems... 

Two yohimbine stereoisomers [( )-445 and ( )-446] having epialloyohim-bane skeletons have been synthesized from the previously prepared (220) epiallo nitrile ester 405, using the following reaction sequence Dieckmann condensa-... 

Starting materials which are only sparingly soluble in water may require solvents that are either partially or entirely organic. Diazotization can either be carried out as usual with an aqueous sodium nitrite solution, or alternatively with nitrosylsul-furic acid or an organic nitrite. Appropriate solvents must be stable to the reactants. Examples include aromatic hydrocarbons, chlorohydrocarbons, glycol ethers, nitriles, esters, and dipolar aprotic solvents, such as dimethyl formamide, dimethyl sulfone, tetramethylene sulfone, tetramethyl urea, and N-methylpyrroli-done. 

Direct coupling of carbon nucleophiles with 1,3-dinitrobenzene is promoted by ultraviolet irradiation in the presence of quaternary ammonium fluorides, which can act not only as the base to generate the carbon nucleophile, but also as a proton transfer agent in the rearomatization step [83], The dinitrobenzene acts as the electron acceptor in the photochemical step. No reaction occurs in the absence of the fluoride and, surprisingly, although simple ketones, nitriles, esters and fl-kcto esters react, pentan-2,4-dione does not. 

Selected examples of the alkylation of aliphatic nitriles, esters and ketones... 

Carboxylic acids can be prepared by oxidising primary alcohols and aldehydes and hydrolysing nitriles, esters and amides. 

Similarly, lipase-catalyzed kinetic resolution has also been applied to intermediate nitrile alcohol 46 (Scheme 14.14). Best results were obtained by using immobilized Pseudomonas cepacia (PS-D) in diisopropyl ether, leading to excellent yield and enantiomeric excess of the desired (5)-alcohol 46a, along with (/J)-nitrile ester 47. Reduction of 46a with borane-dimethylsulhde complex, followed by conversion to the corresponding carbamate and subsequent lithium aluminum hydride reduction gave rise to the desired (S)-aminoalcohol intermediate 36, a known precursor of duloxetine (3). 

Die Herstellung von 5-Amino-4-aminocarbonyl-74b 76, 5-Amino-4-alkoxycarbonyl-73b,"74a.b soWje 5-Amino-4-cyan-imidazolen73a-b-74b aus Derivaten von Amino-malonsau-re-amid-nitril, -ester-nitril bzw. -dinitril, Orthocarbonsaure-triestern und Ammoniak bzw. Aminen ist verwandt mit den auf S.46ff., 49f. beschriebenen Reaktionen. 

The 3-methyl group of nitrile 2b selectively activates C-2 for intramolecular electrophilic substitution so that only one isomer [3b (30%)]18 is formed. Cydization of nitrile esters 4 in the presence of hydrogen chloride did not lead to the expected ketenimmonium chlorides, l-amino-3//-pyrrolizines (5) being formed instead. This may be caused by conjugation of the 1-amino and the 2-alkoxycarbonyl groups on the 1,2-double bond. The dihydropyrrolizinone (6a) could be obtained from compound 5 (R = Me)19 only under drastic conditions.20... 

During synthetic studies on the benzophenanthridine alkaloids, the nitrile ester 1 was treated with sodium hydride in THF in the expectation that a Thorpe-Dieckmann type of reaction would... 

Reduction of thiol esters. Thiol esters, R COSR2, are reduced to primary alcohols, R CH2OH, in high yield by NaBH4 in C2H5OH without reduction of nitrile, ester, and amide substituents.7... 

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