Methyl cyanoformate

The question of whether the commercially available benzoyl cyanide (PhCOCN), methyl cyanoformate (MeOCOCN), and R2NCOCN are formed (cf, however. Ref... 

Recently, Ohwada has employed benzoxazines as the starting precursor for various p,p-unsubstimted o-QMs (Fig. 4.4).3 In this protocol, the benzoxazine is gently warmed in some cases, 50 °C proves sufficient to expel methyl cyanoformate and... 

Cyclon Methyl Cyanoformate and Ethyl Cyanoformate Mixture CIO-A... 

D-Triazoles have been isolated from the reaction of several activated nitriles, such as cyanogen, cyanogen halides, methyl cyanoformate, and cyanic acid esters, with diazoalkanes. The reaction can formally be regarded as a 1,3-dipolar cycloaddition. The v-triazoles may be... 

Synthesis of p-Ketoesters by C-Acylation of Preformed Enolates with Methyl Cyanoformate Preparation of (la,4ag,8ao)Methyl 2-Oxo-decahydro-l-naphthoate... 

If the C=N function is attached to an electron-withdrawing group, 1,3-dipolar cycloaddition with diazoalkanes occurs leading to 1,2,3-triazoles (5, 276). When diazomethane is used, the initially formed NH-triazole is not isolated due to a rapid subsequent NH deprotonation followed by N-methylation. Consequently, a mixture of the three Wmethyltriazoles is formed when methyl cyanoformate (71) (216) or trichloroacetonitrile (276) (217) is treated with excess diazomethane (Scheme 8.51). Huisgen and co-workers found that methyl diazoacetate reacts with TCNE by a 1,3-dipolar cycloaddition at the C=C bond and not, as published earlier by other authors, at one of the nitrile functions (72). 

A mixture of 200 mg (2.35 mmol) of methyl cyanoformate and 137 mg (0.566 mmol) of benzoyl peroxide in 10 mL (77 mmol) of 2,3-dimethylbutane is placed in a Pyrex ampoule. After 5.5 h at 99 °C, analysis of the reaction mixture by vPC shows that the nitrile is the only monomeric product yield 77%. 

More recently, Hoppe et all63 also reported a stereoselective synthesis of a P -amino-u -hydroxy enone and its transformation to a 1,2-dihydroxyethylene isostere (Scheme 29). The addition of dilithium dimethylcyanocuprate to the conjugated C=C bond proceeds smoothly to produce a Z-enolate. The C-methoxycarbonylation with methyl cyanoformate forms the epimeric mixture of the 3-oxo ester. The product is then reduced with sodium cyanobo-rohyde to provide a protected form of the 1,2-dihydroxyethylene isostere. 

Transition-metal catalyzed transfer of acylcarbenes to nitriles leads to 1,3-oxazoles via nitrile ylide intermediates123. The corresponding nitrile ylide chemistry derived from acyl(silyl)carbenes still awaits a closer look, but it has been shown that the rhodium-catalyzed decomposition of 198 in the presence of methyl cyanoformate and benzaldehyde provides 1,3-oxazole 221 (equation 71) exclusively120. This implies that the carbene moiety has been transferred only to the nitrile but not to the aldehyde. 

A study of gas-phase reactions of benzyl and methoxide anions with alkyl formate and other esters has revealed some differences in behaviour of these anions of comparable basicity.184 The delocalized benzyl anion and localized methoxide ion engage in exclusive transacylation and proton transfer, respectively, on reaction with alkyl formates. However, proton transfer is sufficiently exothermic to dominate when benzyl anion reacts with methyl acetate. Both anions react with methyl benzoate, methyl trifluoroacetate, and methyl cyanoformate by competing transacylation and S 2 reactions. 

The photocatalytic radical generation was also used in additions to methyl cyanoformate 143 [240]. The product distribution was dependent on the reaction temperature. At room temperature ot-imino esters 144 were formed in 51-99% yield, while at 90 °C nitriles 145 were isolated in 59-76% yield. At low temperature, the iminyl radical 140C generated by the radical addition, abstracts a hydrogen atom from the substrate to continue a chain reaction, while its fragmentation to the nitrile prevails at high temperature, generating carbon dioxide and a methyl radical 146, which acts as a chain carrier. 

To a suspension of cuprous iodide (0.03 mol) in 100 ml THF was added 25 ml dimethyl sulfide. The solution was cooled to -78 °C, phenyl magnesium bromide (0.06 mol) dissolved in diethyl ether added, stirred one hour, and 2-cyclohexenone (0.03 mol) dissolved in 10 ml THF added. The mixture was warmed to 0°C over 2 hours then re-cooled to -78 °C. It was treated with 15 ml hexamethyl-phosphoramide, stirred 30 minutes, treated with methyl cyanoformate (0.09 mol), and warmed to ambient temperature overnight. The mixture was poured into 100 ml 2M HCl, the organic phase separated, and the aqueous phase extracted with CH2CI2. The combined organic extracts were concentrated, the residue triturated with NH4CI, water, brine, dried, and 3.2 g product isolated as an oil. 

Keto esters. Methyl cyanoformate reacts rcgiosclcctivcly with preformed lithium cnolatcs in the presence of HMPT at -78° to give (j-keto esters in generally high yield. Sodium and potassium cnolatcs arc unreactive. 

Methyl cyanoformate. Zinc, y KETO esters Cyclopropenone 1,3-propane diyl ketal. 1-Ethoxy-1-trimelhylsilyloxycy-clopropane. Methyl a-chloro-a-phenyl-thioacclate. Titanium(IV) chloride. 

Methyl cyanoformate, 0=C. (1). The reagent is readily available by reaction... 

Rhodiumcatalyzed decomposition of 10a in the presence of benzaldehyde and methyl cyanoformate does not afford the dihydrooxazole derived fi om carbonyl ylide 21, but rather the interestingly functionalized 1,3-oxazole [19]. This product is likely to arise from cyclization of the nitrile ylide intermediate 26 [20]. 

All the war gases have not been included in Table XII, but only the most important. Those not included may be easily classified into their proper groups. Acrolein, for instance, in the aldehyde group, lewisite and diphenyl cyanoarsine in that of the arsines, methyl cyanoformate and ttiethyl chloroformate in that of the esters. 

Since the war other analogous compounds have been studied, especially from the physiopathological point of view. Such are methyl cyanoformate and ethyl cyanoformate, which are powerful lachrymators but are easily decomposed by the action of water. 

Because of its strongly irritant properties, it has been used in insecticidal preparations " Zyklon A, which is a mixture of 90% of methyl cyanoformate and 10% of methyl chloroformate, and Zyklon B, a mixture of liquid hydrocyanic acid and irritant chlorinated and brominated compounds. ... 

After formation of the enolate by deprotonation with LiHMDS, the ester moiety is introduced by reaction with methyl cyanoformate to give P-ketoester 20 in 70 % yield over three steps. Structure 20 represents a 1,3-dicarbonyl compound that preferentially exists in the enol form. 

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