Allene nitrile

In the first method a secondary acetylenic bromide is warmed in THF with an equivalent amount of copper(I) cyanide. We found that a small amount of anhydrous lithium bromide is necessary to effect solubilization of the copper cyanide. Primary acetylenic bromides, RCECCH Br, under these conditions afford mainly the acetylenic nitriles, RCsCCHjCsN (see Chapter VIII). The aqueous procedure for the allenic nitriles is more attractive, in our opinion, because only a catalytic amount of copper cyanide is required the reaction of the acetylenic bromide with the KClV.CuCN complex is faster than the reaction with KCN. Excellent yields of allenic nitriles can be obtained if the potassium cyanide is added at a moderate rate during the reaction. Excess of KCN has to be avoided, as it causes resinifi-cation of the allenic nitrile. In the case of propargyl bromide 1,1-substitution may also occur, but the propargyl cyanide immediately isomerizes under the influence of the potassium cyanide. 

Note 2. If the addition is performed at too fast a rate, all of the copper cyanide may dissolve temporarily. The free KCN, present in the solution may cause partial resinification of the allenic nitrile. 

A synthetic approach to hyperevolutin A 421, prenylated bicyclo[3.3.1] nonanone derivative, with an acylated phloroglucinol-type fragment, has been described (464). Intramolecular allene-nitrile oxide cycloaddition of 422 has been used to construct the bicyclic framework and the vicinal quaternary centers in cycloadduct 423. 

Allenic nitriles 570 reacted with nBu2CuLi to give /),y-unsaturated allylic nitriles 571 [262]. 

Allenic nitrile 9 gave unsymmetrical head-to-tail cycloadduct 10 as a mixture of Z- and -isomers [10],... 

Allenic nitriles and esters provide nonconjugated products (equations 54 and 55).76... 

Allenic ketones and esters are found to react with azides by addition, preferentially to the activated double bond in the a, -position to the ester or keto group, although no regioselectivity is observed.254 Allenic nitriles undergo similar additions, and unstable methylene triazolines are obtained (Scheme 78).301... 

Landor and his colleagues studied the reaction of 2-aminopyridines with allenic nitriles and phenylpropynenitrile [81TL4127 88JCS(P1)975]. 

The reaction of 2-aminopyridine hydrochlorides and allenic nitriles either neat at 90°C for 20 hours or in boiling methylene chloride for 15 hours afforded unstable 2-imino-2//-pyrido[l,2-a]pyrimidine hydrochlorides 71, which could be isolated as hydrates in about 50% yield [88JCS(P1)975]. If the reactions were carried out in boiling 95% ethanol for 72 hours, the initially formed 2-imino-2//-pyrido[ 1,2-a Ipyrimidines 71 were hydrolyzed and 2-pyridyl ketones 73 could be isolated. Under the latter conditions 3-hydroxy-2-aminopyridine gave 2-iminopyridopyrimidines 74, which were stabilized by the formation of zwitterionic structures (Scheme 5). [Earlier the ring-opened products 73 (R = H, 3-NH2) were described as a 4-imino-4/7-pyrido[ 1,2-a]pyrimidine derivative 72 (81TL4127)]. 

The reaction of allenic nitrile and 2-amino-6-methyl- and -4,6-dimethyl-pyridine gave a mixture of mono- and bis-adducts tentatively formulated as 75, 76, and 77 [88JCS(P1)975], while 2-amino-3-nitro-, 2,6-diamino-, and 2-amino-3,5-dibromopyridines do not react even after refluxing for 120 hours. 

Hydration of attenic nitriles. 4,4-Dialkyl-substitutcd allenic nitriles (1) are converted into allenic amides (2) in 60 70% yield by reaction with hydrogen peroxide in alcoholic sodium hydroxide. 

Similarly, treatment of ynones with DECP and LiCN leads to the corresponding cyanophosphate, which, on reaction with cuprates in THF at low temperature, give the allenic nitrile by elimination of phosphate. Only a few reports describe the properties of DECP as a phosphorylation reagent for imidazoline nitrogen atoms, phenols, and Grignard reagents. ... 

Yoneda. R.. Inagaki, N.. Harusawa, S., and Kurihara, T., A new synthesis of allenic nitriles from ynones via cyano phosphates, Chem. Pharm. Bull., 40, 21, 1992. 

A synthesis of 7,8-dioxygenated isoquinolines (found in cularine alkaloids) requires o-metallation of the Af-protected -phenylethylamine. The primary amine is protected by reaction with two equivalents of trimethylsilyl chloride. Phenylhydroxylamine and the allenic nitrile (53.7) react in boiling ethanol over 48 h to give a high yield of 4-aminoquinoline—an important intermediate for the synthesis of some antimalarial drugs. 

The mode of reaction of allenes with 1,2-diamines seems to be strongly dependent on the substituents on the allene. Allenic nitriles give imidazoles via double Michael addition but the 1,3-diester (114), on reaction with o-phenylenediamine, gave only the 1,5-benzodiazepine (116). The enamine intermediate (115) apparently strongly favours a 1-exo-trig cyclization over the competing 5-exo-trig alternative. ... 

Hydrolysis of (63) (formed from 2-aminopyridines and allenic nitriles) under mild basic conditions afforded (64) (Equation (11)) <89JCS(P1)609>. Two ring substituents of bicyclic (65) participated in a transformation with nitrous acid. Diazotation followed by cyclization afforded the tricyclic compound (66) (Equation (12)) <86JCS(Pl)7ll>. 

Monosubst. acetylene Disubst. acetylene C==C=CH2 Allene Nitrile, aliphatic Nitrile, aromatic... 

Allen -Nitril-Yliden ist eine auffallend langwellig (4,58-4,70 p) ver-schobene Nitrilbande gemeinsam. 

Fomum and co-workers reported a novel synthesis of biologically active pyrimido[l,2-ajbenzimidazoles 10 from aminobenzimidazoles 8 and allenic nitriles 9 in good yields. Some of these heterocycles showed modest antibiotic and antiarrhythmic properties <01JCS(P1)457>. 

The well known palladium-catalysed insertion of carbon monoxide into substituted aryl halides has been elaborated to provide a useful synthesis of benzo-diazepinones, and the reaction of 1,2-diamines with allenic nitriles has been... 

The method of formation of (326) involves a 1,3-dipolar cycloaddition, and the overall transformation is somewhat similar to those discussed earlier in references 27, 62, and 102. The addition of 2-aminoethanethiol to allene nitriles gives adducts which, on heating, cyclize to form thiazOlines (327). However, when... 

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