Malononitrile salts

Malononitrile salts. Electrosynthesis of air-stable potassium and ammonium salts of / -cycanophenyl malononitrile in liquid ammonia on a platinum grid electrode was reported Treating 10 with aliphatic alcohols and hydrohalic acids at elevated pressures gave dialkyl propanediimidate dihydrohalidesAcid addition salts (p-toluenesulfonate, methanesulfonate and hydrochloride) of aminomalononitrile were prepared ". Bis(methylthio)methylene-indanedione 123 reacted with 10 to yield 124 ". ... 

P4S10 to yield pyridinethione 140, which by methylation afforded 141. Dichloro-malononitrile was cyclized to give 2,5-dichloronicotinonitrile. Arylazomalononitrile 142 was reacted with guanidinium salt 143 to yield arylazopyrimidine 144170,171 Perhydropyrimidines and -triazines were prepared from (H2N)2C=N—CN 2-ethyl-2-phenylmalononitrile. Tetracyanoperhydropiperazines were obtained from amino-malononitrile salts and aromatic aldehydes... 

Health and Safety Factors. Malononitrile is usually available as a soHdifted melt in plastic-Hned dmms. Remelting has to be done carefully because spontaneous decomposition can occur at elevated temperatures, particularly above 100°C, in the presence of impurities such as alkaHes, ammonium, and 2inc salts. Melting should be carried out by means of a water bath and only shordy before use. Occupational exposure to malononitrile mainly occurs by inhalation of vapors and absorption through the skin. Malononitrile has a recommended workplace exposure limit of 8 mg/m, an LD q (oral, rats) of 13.9 mg/kg, and is classified as slight irritant (skin irritation, rabbits). Transport classification RID/ADR 61, IMDG-Code 6.1, lATA/ICAO 6.1. 

Hydrochlorides of. V-(2-cyanovinyI)benzene-l,2-diamine, prepared from benzenc-1,2-diamine and (ethoxymethylene)malononitrile or ethyl cyano(ethoxymethylene)acetate, cyclize to salts of 3//-l,5-benzodiazepin-2-amine 1 on heating.254a b... 

As stated above under TNMe, in Ger during WWII, the prepn of TeNMe by this process was scaled up for use as an intermediate and as a substitute for nitric acid in the V-2 rocket (Ref 26). A pilot plant was built at Newark, NJ for prodn using this procedure. It was destroyed by an expln in 1953 and not rebuilt (Refs 33 44). Other prepns of lesser importance are by the action of Ag nitrite on iodotrinitro-methane (Ref 3) by the action of 90% nitric acid and 25% oleum on malononitrile, yield 45% (Ref 40) by the action of mixed acid on a number of aromatic nitrocompounds, of which nitrobenzene, dinitrobenzene, and nitronaphtha-lene gave the best yields (Ref 13a) and by the action of nitryl chloride on salts of TNMe. 

Unlike such unstable intermediates, the first, rare example of reversible dissociation of a carbon-carbon a bond into a stable carbocation and carbanion was reported for a nitro-dicyano compound (20) prepared from trimethyl- and triphenyl-cyclopropenylium tetrafluoroborate ([4" ]BF4 and [5 JBFJ) with the potassium salt of p-substituted-phenylmalononitrile anions (Arnett et al., 1983 Troughton et al., 1984 Arnett and Molter, 1985). Other ionically dissociative malononitrile derivatives have been prepared from such carbocations as the tropylium [S ] (Arnett and Troughton, 1983) and the tris(p-methoxyphenyl)methylium [93 j (Arnett and Troughton, 1983) ions. 

Reactions of a,(3-unsaturated acylzirconocene chlorides with stable carbon nucleophiles (sodium salts of dimethyl malonate and malononitrile) at 0°C in THF afford the Michael addition products in good yields (Scheme 5.38). Direct treatment of the reaction mixture with allyl bromide in the presence of a catalytic amount of Cul -2LiCl (10 mol%) in THF at 0 °C gives the allylic ketone in a one-pot reaction. This sequential transformation implies the electronic nature of a,P-unsaturated acylzirconocene chloride to be of type E as shown in Scheme 5.37. 

The treatment of isopropylidene phenylaminomethylenemalonates (1319) with ethyl cyanoacetate or malononitrile in the presence of potassium hydroxide in DMF at 90°C afforded the potassium salts of derivatives of Meldrum s acid in 74% yields, which were converted without isolation to pyridones (1320) in 91% yield on the action of aqueous hydrochloric acid [78ZN(B)1550]. 

Several 9-(2, 3 -0-isopropylideneglycerolyl)-8-azahypoxanthine and 8-aza-adenines were synthesized by a 1,3-dipolar cycloaddition of racemic or (5)-l-azidoglycerolyl derivative 1084 with the sodium salt of malononitrile or cyanoacetamide to afford the intermediate triazoles 1085 and 1088, which... 

Condensation of ester (44e) with the anion of malononitrile gave the alkene (44g) <91JPR35>. Oxadiazole (43e) and triethyl phosphite gave a methane phosphate which underwent a Wittig reation with aldehydes ArCHO to form alkenes (43f). When the alkyl side chain contained an active methylene group, as in (43g), reaction with arenediazonium salts ArN2X yielded arylhydrazones (43h) <88LA909>. 

The salts (294) with malononitrile and triethylamine in boiling acetonitrile yield the new class of meso-ionic heterocycles in which the exocyclic carbanionoid residue is a biscyanomethylene group. The diphenyl derivative (296, R = R = Ph) has a dipole moment of 9.54 D in benzene solution. ... 

The 6//-l,3-thiazin-6-iminium hydroperchlorate salts 78-81 give interesting products when treated with nucleophiles <2003H(60)2273>. Hydrolysis of 6-imino-6//-l,3-thiazine hydroperchlorate 78 affords (2Z,4Z)-2-cyano-5-hydroxy-5-phenyM-azapenta-2,4-dienethioamide 82 in excellent yield, while treatment with morpholine gives 2-(morpholinomethylene)malononitrile 83 and thiobenzamide. The 5-(ethoxycarbonyl) -(methylthio)-2-aryl-6/7-l,3-thiazin-6-iminium salts 79 and 80 react with hydroxide or morpholine to afford ethyl 4-(methylthio)-2-aryl-6-thioxo-l,6-dihydropyrimidine-5-carboxylates 84 and 85. In the case of the 4-chloro analogue 80, the (Z)-ethyl 2-(5-(4-chlorophenyl)-37/-l,2,4-dithiazol-3-ylidene)-2-cyanoacetate 87 is also formed for the reaction with sodium hydroxide. The 1,2,4-dithiazoles 86 and 87 can be obtained as the sole product when 79 and 80 are treated with sodium acetate in DMSO. Benzoxazine 88 is isolated when the iminium salt 81 is treated with morpholine or triethylamine. Nitrile 89 is formed as a ( /Z)-mixture when 6-imino-67/-l,3-thiazine hydroperchlorate 79 is reacted with triethylamine and iodomethane in methanol <2003H(60)2273>. 

The constrained bis(oxazolines) 9a and 9b can be constructed beginning with malononitrile 32 as shown by Ghosh and co-workers. Thus, treatment of 32 with anhydrous hydrochloric acid in dioxane, as shown by Lehn and co-workers, yielded imidate salt 33 (Fig. 9.9). Condensation of the imidate salt with commercially available (15,2/ )-l-aminoindan-2-ol afforded the conformationally constrained bis(oxazoline) inda-box 9a. Alkylation at the bridging methylene of 9a was carried out by Davies and co-workers.Treatment of 9a with lithium diisopropylamide followed by alkylation with methyl iodide afforded 9b. Alternatively, alkylation with diiodoalkanes incorporated ring systems at the bridging position (structures 34a-d). 

Treatment of the bromide 93 with the potassium salt of 1,1-dicyanothioacetanide 94 gave the dihydrothiadiazole 95 via initial nucleophilic displacement of the bromine by the sulfur atom in 94, cyclization and then loss of malononitrile <99JCR(S)184>. 

The same zwitterions can give pyrid-2-ones (798) when treated with dimethyl acety-lenedicarboxylate (71AG(E)925). Quaternary pyrimidinium salts are attacked by the anions from diethyl malonate or malononitrile to produce pyrid-2-ones (799) or 2-aminopyridines (800) respectively (74RCT233). Quinazoline Af-oxide (801) reacts with ketones on heating to give quinolines the reaction is assumed to be initiated by attack at C-4, with subsequent... 

Thiophenes can be synthesized from a sequence involving the reaction of activated methylene compounds with carbon disulfide in base. The resulting disulfide salts, without isolation, are reacted with phenacyl bromide to afford highly substituted thiophenes, 78. Compound 78 reacts with ethyl cyanoacetate, malononitrile, or acrylonitrile to afford thieno[3,2-/ ]pyridine derivatives <1995CCC1578>. 

Synthesis of tetrahydropyrido[2,3-,y pyrimidin-7-ones 537 in a microwave-assisted one-pot cyclocondensation of a,/3-unsaturated esters with active methylene compounds (malononitrile or methyl cyanoacetate) and amidine salts (guanidine or benzamidine) in NaOMe/MeOH for 10min has been reported <2003TL5385>. 

In a 12-1. three-necked, round-bottomed flask, fitted with a powerful stirrer (Note 1) and a reflux condenser, are placed 1260 g. (15 moles) of cyanoacetamide,1 1 kg. of salt (Note 2), and 5 1. of ethylene dichloride. After the mixture has been stirred rapidly for 15 minutes, 800 ml. (8.75 moles) of phosphorus oxychloride is added and the mixture is refluxed for 8 hours in an oil bath (Note 3). After the mixture has been cooled to room temperature, it is filtered and the solid is washed with 500 ml. of ethylene dichloride. The solvent is distilled from the combined filtrates in a 12-1. flask, and the residual crude nitrile is decanted into a 1-1. flask (Note 4) from any solid that may have separated. A fractionating column, condenser, and fractionating receiver are attached, and the mal-ononitrile is distilled under reduced pressure. The fraction boiling at 113-118°/25 mm. weighs 570-654 g. (57-66%) (Note 5). This material may be freed from a small amount of phosphorus oxychloride which is present by redistillation. After a fore-run of about 5 ml., the malononitrile distils smoothly at 92-94°/8 mm. 

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