Aminimides

Aminimides also enter into a reaction with MA derivatives. AT-ethoxycar-bonyliminopyridinium ylide 69 gives a 73% yield of the adduct 70. N-phenylmaleimide is also reported to yield an analogous product.Dialkyl fumarate and maleate also undergo similar reaction. 

A very unusual reaction of 2-isopropyl-2-oxazoline 71 (R=H) needs mention. Nehring and Seelinge/ reported that on refluxing a 1,2-dichloroethane solution of 71 and MA, a 77% yield of the product 72 was obtained. When R = methyl, a 48% yield of a similar adduct was formed. The structure was proved by NMR, IR spectroscopy, elemental analysis, and hydrolysis studies. It is interesting to note that the hydrogen atom of the isopropyl group is so active for Michael addition, since that would be required as part of the sequence. 

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HydroxyethyUiydrazine (11) is a plant growth regulator. It is also used to make a coccidiostat, furazoHdone, and has been proposed, as has (14), as a stabilizer in the polymerization of acrylonitrile (72,73). With excess epoxide, polysubstitution occurs and polyol chains can form to give poly(hydroxyaLkyl) hydrazines which have been patented for the preparation of cellular polyurethanes (74) and as corrosion inhibitors for hydrauHc fluids (qv) (75). DialkyUiydrazines, R2NNH2, and alkylene oxides form the very reactive amineimines (15) which react further with esters to yield aminimides (16) ... 

The preparation and properties of these tertiary aminimides, as weU as suggested uses as adhesives (qv), antistatic agents (qv), photographic products, surface coatings, and pharmaceuticals, have been reviewed (76). Thermolysis of aminimides causes N—N bond mpture foUowed by a Curtius rearrangement of the transient nitrene (17) intermediate to the corresponding isocyanate ... 

Acyl aminimides have proved useful as surface-active and antimicrobial agents and as an intermediate for isocyanate preparation (50). 

JCS(P2)71]. Reportedly, perhydropyridazine-3,6-diones react with cin-namaldehyde to yield l-phenyl-l//-pyrazolo[l,2-n]pyridazines. However, the authors cited did not present convincing evidence that excludes possible formation of acyclic aminimides (83MI3). 

The reaction of aminimide 251 with electron-poor olefins affords py-razolo[1,2-a]-1,2,4-triazoles (252) [72ZOR1750 80JCS(P1)843 81JOC614] (Scheme 30). 

Lockley and Lwowski167 showed that aminimides (235) dissociate upon heating, especially if the substituent at the 4-position is bulky. 

J.J. Kabara and G.V. Haitsma, Aminimides, II, Antimicrobial effect of short chain fatty acid derivatives, J. Am. Oil Chem. Soc. 52 (1975) 444-447. 

The development of polymer latices and their pigmentation and application is still at an early stage. However, an emulsion formulation suitable as a base for paints has been given. (46) Here a difunctional aminimide(below) is included at 51 in the (CH N lT0C(CH2)gC0]r N (CH ) ... 

The reaction of ethoxycarbonyl nitrene, generated by decomposition of the azide or by the a-elimination method, with enamines gave mixtures of aminimides and a-amino ketone derivatives30.. V-Methoxycarbonyl. A -cyano and N-sulfonyl azides reacted with 1,2-31 and 1,4-dihy-dropyridines32 to afford directly the corresponding aziridines 9 and 10. The configuration of the aziridine 10, relative to the R substituent, was not determined. 

Dialkylamino isocyanates are known transient intermediates and, in the absence of other reagents, have been shown to dimerize. When the cyclic aminimide (c) was heated at 130°C under vacuum (0.3 mm) for 3 h, (d) was obtained in 89% yield. At higher temperature (d) was formed but rearranged to (e) as depicted in scheme 146. 

The chemistry of aminimides has been reviewed elsewhere (Ref. 204, 205) and the chemistry of dimethyl amino isocyanate, prepared in the form of dimer (d) through a phosphoramide synthesis, studied (206). 

In a preferred example, when UDMH in anhydrous THF was added to a solution of 1-chloroethyl chloroformate in THF at 10-20°C, the intermediate carbazate (a) was formed. After filtration to remove the UDMH hydrochloride, we accomplished a cyclisation to (b) just by refluxing the THF solution for 1 h.. The resulting hygroscopic salt (b) precipited immediately in 71 % overall yield. In solid form, (b) is stable undefinitely at room temperature. The cyclic aminimide (c) was then easily prepared from (b) by treatment with a resin supported base in high yield. The three steps of the synthesis are depicted in scheme 145. 

Scheme MS New cyclic aminimide from UDMH and ACBCI.

Table 3-25 Preparation of UDMH derivatives through reaction of cyclic carbal-koxy aminimide (c) with a nucleophile Nu-H.

Benecke, H. P., Wikel, J. H. Curtius rearrangement in aminimides. Tetrahedron Lett. 1972, 289-292. 

Fig. 13.4 Amide surrogates aminimides, phosphonamides, and sulfonamides and associated dihedral angles.

The photolysis of aminimides produces acylnitrenes, which have usually been trapped in intermolecular reactions.151,159 Again, isocyanates often accompany the reactions. The thermolysis of 2,4,6-triphenylpyridine N-acylimines at 170-250°C affords isocyanates in good yields.160... 

Urethane group containing-coatings can also be obtained from other types of compounds capable of generating Isocyanates. These are aminimides, especially those based on methacrylic acid (189-191) ... 

Aminimides decompose on heating to yield isocyanate groups as follows ... 

Aminimides can also be copolymerized with other vinyl monomers, yielding acrylic resins. Hence, either urethane homopolymers or urethane copolymers can thus be obtained. 

Photolysis of the phosphinic aminimide (83) in methanol gives the amide (85) in high yield, not via nitrene formation but by initial... 

The diazepinoindole system (62) has been synthesized, in high yield, by the reaction of the aminimide (61) with base." The full report on the thermal ring-expansion of 4- and 6-vinyl-l,2,5,6-tetrahydropyridine and 2-vinylpiperi-dine A -imides has now appeared. ... 

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