Dinitriles synthesis

Enone formation-aromatization has been used for the synthesis of 7-hydro-xyalkavinone (716)[456]. The isotlavone 717 was prepared by the elimina-tion[457]. The unsaturated 5-keto allyl esters 718 and 719, obtained in two steps from myreene. were subjected to enone formation. The reaction can be carried out even at room temperature using dinitriles such as adiponitrile (720) or 1,6-dicyanohexane as a solvent and a weak ligand to give the pseudo-ionone isomers 721 and 722 without giving an allylated product(458]. 

Another example is the du Pont process for the production of adiponitrile. Tetrakisarylphosphitenickel(0) compounds are used to affect the hydrocyanation of butadiene. A multistage reaction results in the synthesis of dinitrile, which is ultimately used in the commercial manufacture of nylon-6,6 (144-149). 

KAISEH - JOHNSON - MIDDLETON Oinilniecyciizatlon Synthesis of heterocycles by cyciizatlon of dinitriles by means of HBr... 

Some researchers have elaborated synthesis of PCSs employing bis(nitrile oxide)s as 1,3-dipoles and diynes, dinitriles, and a number of other compounds as dipolaro-philes154-156). 

Dimethylphenol, synthesis of, 383 /V,/V-Dimorpholinodicthyl ether (DMDEE), 225, 230 Dinitrile-diamine polyamides, 158 Dioctyltin dilaurate, 232 Diol-functionahzed telechelic polymers, 457... 

The study concerns the desymmetrization of the prochiral dinitrile (16) with preferential formation of the (Ji)-17, which was known to be a chiral intermediate in the synthesis of the cholesterol-lowering therapeutic drug (18) (Lipitor, Sortis, Torvast, etc.) as shown in Scheme 2.3. 

Reactions of this type are called electrochemical hydrodimerization. They are of great value for the synthesis of various bifunctional compounds. A reaction that has found wide commercial nse is the hydrodimerization of acrylonitrile to adiponitrile (the dinitrile of adipic acid) ... 

The Gas-Phase Ammoxidation of /i-Hexane to Unsaturated 5 Dinitriles, Intermediates for Hexamethylenediamine Synthesis... 

This chapter reports about an investigation on the catalytic gas-phase armnoxidation of u-hexane aimed at the production of 1,6-Ce dinitriles, precursors for the synthesis of hexamethylenediamine. Catalysts tested were those also active and selective in the ammoxidation of propane to aciylonitrile mtile-type V/Sb and SnA /Nb/Sb mixed oxides. Several A-containing compounds formed however, the selectivity to cyano-containing aliphatic linear Ce compounds was low, due to the relevant contribution of side reactions such as combustion, cracking and formation of heavy compounds. 

Hexamethylenediamine (HMDA), a monomer for the synthesis of polyamide-6,6, is produced by catalytic hydrogenation of adiponitrile. Three processes, each based on a different reactant, produce the latter coimnercially. The original Du Pont process, still used in a few plants, starts with adipic acid made from cyclohexane adipic acid then reacts with ammonia to yield the dinitrile. This process has been replaced in many plants by the catalytic hydrocyanation of butadiene. A third route to adiponitrile is the electrolytic dimerization of acrylonitrile, the latter produced by the ammoxidation of propene. 

Zhu, D., Mukherjee, C., Biehl, E.R. and Hua, L. (2007) Nitrilase-catalyzed selective hydrolysis of dinitriles and green access to the cyanocarboxylic acids of pharmaceutical importance. AdviOU cd Synthesis and Catalysis, 349, 1667-1670. 

Porphyrazines (pz), or tetraazaporphyrins, are compounds that can be viewed as porphyrin variants in which the meso carbon atoms are replaced with nitrogen atoms, as Fig. 1 shows (1). This difference intrinsically gives porphyrazines discrete physiochemical properties from the porphyrins. In addition, despite their similar molecular architecture, porphyrazines are prepared by an entirely different synthetic route than porphyrins—by template cyclization of maleonitrile derivatives, as in Fig. 2, where the open circle with the A in it represents the peripheral substituent of the pz—rather than by the condensation of pyrrole and aldehyde derivatives (1). The pz synthetic route allows for the preparation of macrocycles with chemical and physical properties not readily accessible to porphyrins. In particular, procedures have been developed for the synthesis of porphyrazines with S, N, or O heteroatom peripheral functionalization of the macrocycle core (2-11). It is difficult to impossible to attach the equivalent heteroatoms to the periphery of porphyrins (12). In addition, the preparation and purification of porphyrazines that bear two different kinds of substituents is readily achievable through the directed cocyclization of two different dinitriles, Fig. 3 (4, 5, 13). 

Figure 3. Synthesis of unsymmetrical porphyrazines via cocyclization of two dinitriles.

Following the reports of sulfur appended porphyrazines, Fitzgerald et al. (28) reported a facile synthesis of alkyl appended porphyrazines in 1991, preparing the dialkyl dinitrile precursors from alkynes via a Rosenmund von Braun reaction. Later, these types of dinitriles were used in mixed cyclizations to prepare porphyrazines with three dipropyl substituents (6,29). An intriguing extension was the... 

Porphyrazines are typically synthesized by a templated cyclization of substituted dinitriles, Fig. 2 (2). The most common divalent metal used as the template for this reaction is Mg2+, usually as the butoxide or propoxide, although other group 1(1 A) and 2(IIA) metals have been reported (41). Mixed cyclizations, which utilize two different dinitriles, Fig. 3, in principal, would give a statistical mixture of six different products or isomers. The truly enabling synthetic foundation for modem pz chemistry is the development of strategies directed toward the synthesis... 

Sandwich complexes of porphyrazines are prepared by direct intercalation of lanthanides between two pz ligands, the route commonly utilized for the preparation of porphyrin sandwich complexes. Interestingly, the synthetic method used for the preparation of bis(phthalocyanines), starting from the dinitrile or the dilithium substituted monophthalocyanine, has never been successfully implemented for the synthesis of porphyrazines (77). 

Synthesis. The first example of a stable, soluble pz peripherally substituted with a heteroatomic moiety involved appended thioether groups, M[pz(.V-Mc)8, as reported in 1980 by Schramm and Hoffman (2) (Scheme 9, 45-48). Mg[pz(5 -Me)s], 46, was prepared in a 60% yield by a magnesium templated macrocyclization of dinitrile, 45. Demetalation with sulfuric acid gave H2[pz(5 -Me)8], 47 (65%) and remetalation with the anhydrous acetate salts of copper and nickel gave 48 (80%) and 49 (65%). 

Synthesis. Porphyrazines Mg[pz(A4)], A = S203 crown, 81a, and Mg[pz(A4)], A = S204 crown, 81e, (35%) were prepared by cyclizing the appropriate crown dinitrile 80. Compounds 81a and 81e were demetalated with trifluoroacetic acid and remetalated with either copper or manganese acetate to form compounds 81b-81d and 81f-81h (Scheme 16) (25-27). 

Synthesis. These macrocycles are prepared from seven-membered ring dinitrile complexes, 84a-84c (Scheme 17), which contain either methylene, sulfur or oxygen in the five position (129). These cyclic dinitriles are synthesized by alkylating maleonitrile dithiolate or derivatives thereof with the corresponding dihalide. The dinitriles 84a-84c can be cyclized in magnesium propoxide to form porphyrazines 85a (33%), 85b (19%), and 85c (27%) (Scheme 17), which can be demetalated with trifluoroacetic to form 86a-86c. Additionally, 86a has been remetalated with nickel (87a, 92%), copper (88a, 95%), and zinc (89a, 94%). The sulfur and oxygen derivatives 85b, 85c, 86b, and 86c are of low solubility and are not suitable for further manipulation. 

Synthesis. The synthesis of the. V-polycthcrol porphyrazines is outlined in Scheme 19. The complex Mg[pz(A4)] (95a, 18%), was prepared by cyclizing dinitrile precursor 94 with 4,7-bis(isopropyloxy)- 1,3-diaminoisoindoline... 

Synthesis. Comacrocyclization of 2,5-diiminopyrrolidine (213) with 5 equiv of bis(dimethylamino)maleonitrile (99) produced 214. Subsequent demetalation with TFA gave 215 in 5% overall yield. Similarly, mixed macrocyclization of 2,5-diiminopyrrolidine 213 with 2,3-dipropyl-maleonitrile (33) produced pz 216 (3%). The yield of this reaction could be improved by conversion of dinitrile (33) into the diiminopyrroline derivative 212 using ammonia, to provide pz 216 in 17% yield. Demetalation of 216 furnished the free base 217 (91%). 

The synthesis of dithienyl photochromes containing a maleic anhydride fragment (a furan-2,5-dione fragment) as the ethene bridge was a difficult problem. Initially, vicinal dinitriles 160 and 162 were used as the starting compounds (Scheme 49). But the latter compounds give a maleic anhydride only in the cis conformations. The separation of the cis and trans isomers is an additional time-consuming laborious problem. 

The synthesis of l,2-bis(thiophen-3-yl)maleic anhydride involves the dimerisation of a 3-cyanomethyl derivative of thiophene (1.45) by reaction with aqueous NaOH in the presence of CCl. Alkaline hydrolysis of the dinitrile (1.46) and dehydration produces the anhydride (1.47) as shown in Figure 1.12. ... 

A very popular route to piperid-4-ones is by a Dieckmann or Thorpe cyclization of appropriate diesters or dinitriles. In most cases the nitrogen atom is tertiary, to avoid the formation of amides as by-products. A simple example is provided by the synthesis of the piperidone ester (129) which, after hydrolysis and decarboxylation, gives the piperid-4-one (130) (45JOC277). The diesters are available by addition of amines to acrylates and so the two ester fragments can be different. For the production of AT-benzoylpiperid-4-one (132) the whole operation from benzamide and ethyl acrylate to the ester (131) can be achieved... 

Preparative routes to 5/7-dibenz[6,e]azepine-6,11 -diones (morphanthridinediones) are based mainly on the cyclization of 2-aminobenzophenone-2 -carboxylic acids and their derivatives (55LA(594)89). Studies on a-aminodiphenyImethane-2 -carboxylic acid reveal that cyclization to 5,11 -dibenz[6,e ]azepinone (188) is much slower at room temperature than the cyclizations of the analogous 2-aminobiphenyl-2 -carboxylic acid and the 2 -aminobiphenylacetic acid (189), which at room temperature cyclize spontaneously to phenanthridone and dibenz[f>,d]azepin-6-one (190) respectively (61JOC1329). The hydrogen bromide-induced cyclization of dinitriles (Scheme 16) is adaptable to the synthesis of 2-amino-7-bromo-3//-azepines and 5H-dibenz[c,e]azepin-7-ones (67JOC3325). Apparently, for unsymmetrical dinitriles cyclization is such as always to give the azepine with the bromo substituent attached to the carbon of the a,j8-unsaturated nitrile as exemplified in Scheme 16. 

Two processes are commonly used for the production of copper phthalocyanine the phthalic anhydride-urea process patented by ICI [33,34] and the I.G. Farben dinitrile process [48], Both can be carried out continuously or batchwise in a solvent or by melting the starting materials together (bake process). The type and amount of catalyst used are crucial for the yield. Especially effective as catalysts are molybdenum(iv) oxide and ammonium molybdate. Copper salts or copper powder is used as the copper source [35-37] use of copper(i) chloride results in a very smooth synthesis. Use of copper(i) chloride as starting material leads to the formation of small amounts of chloro CuPc. In the absence of base, especially in the bake process, up to 0.5 mol of chlorine can be introduced per mole of CuPc with CuCl, and up to 1 mol with CuCl2. 

Barnett, M. Secondo, P. Collier, H. Synthesis and characterization of new l,l -diester, diketone, and dinitrile derivatives of 2,2 -biimida-zole.J. Heterocyclic Chem. 1996, 33,1363-1365. 

Furthermore, we have extended the high-pressure polycondensation to the synthesis of condensation polymers other than polyimides. A successful example was the high-pressure synthesis of polybenzoxazoles starting from the bis-o-aminophenol (or its hydrochloride) and aliphatic dinitriles (Eq. 8) [35]. The polycondensation readily proceeded under high pressure in a closed reaction vessel with the elimination of the by-product of ammonia (or ammonium chloride). 

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