Glutarimide, methylation

That the methyl group in the less substituted isomer of the enamine (20) is axial was borne out by the work of Johnson et al. (18) in the total synthesis of the glutarimide antibiotic //-dehydrocycloheximide (24). The acylation of the morpholine enamine of 2,4-dimethylcyclohexanone (25) with 3-glutarimidylacetylchloride (26), followed by the hydrolysis of the intermediate product (27) with an acid buffer, led to the desired product in 35 % yield. The formation of the product in a rather low yield could most probably be ascribed to the relatively low enamine-type aetivity exhibited by the tetrasubstituted isomer, which fails to undergo the acylation reaction, and also because in trisubstituted isomer one of the CHj groups is axial. Since the methyl groups in the product are trans to each other, the allylic methyl group in the less substituted isomer of the enamine should then be in the axial orientation. 

P-METH YL- P-PHEN YL-ajo -DIC YAN O GLUTARIMIDE (Glutarimide, 2,4-dicyano-3-methyl-3-phenyl-)... 

Research has also been aimed at the development of more-transparent base-soluble matrix resins. For example, novolacs prepared from pure p-cresol absorb less strongly at 250 nm than do typical photoresist novolacs containing a mixture of cresol isomers. Unfortunately, p-cresol novolac is only sparingly soluble in aqueous base and has limited usefulness (28, 57). Other examples of more-transparent matrix resins include poly(dimethyl glutarimide) (PMGI) (58) and copolymers of methyl methacrylate (MMA) and methacrylic acid (MAA) [P(MMA-MAA)]. 

MGIM Methyl methacrylate-co-N-methyl glutarimide copolymer containing x molar percent of the latter comonomer... 

Poly(methyl methacrylate) and its Maleimide and Glutarimide Copolymers... 

Methyl Methacrylate-co-W-methyl Glutarimide Random Copolymers... 

Another series of methyl methacrylate copolymers is constituted by the methyl methacrylate-co-M-methyl glutarimide random copolymers. The chemical structure of the N-mclhyl glutarimide repeat unit is ... 

The copolymers are obtained by the reaction, in solution, of methylamine with PMMA, leading to methyl glutarimide (MCI) cycles randomly distributed along the original PMMA chain backbone. As the content of MCI units varies from 4 to 76%, it is worth considering the percentages of the different triads that can be encountered (the calculations are performed as-... 

The approach developed in this paper, combining on the one side experimental techniques (dynamic mechanical analysis, dielectric relaxation, solid-state 1H, 2H and 13C NMR on nuclei at natural abundance or through specific labelling), and on the other side atomistic modelling, allows one to reach quite a detailed description of the motions involved in the solid-state transitions of amorphous polymers. Bisphenol A polycarbonate, poly(methyl methacrylate) and its maleimide and glutarimide copolymers give perfect illustrations of the level of detail that can be achieved. 

The purpose of this paper is to investigate the mechanical properties (plastic deformation, micromechanisms of deformation, fracture) of several amorphous polymers considered in [1], i.e. poly(methyl methacrylate) and its maleimide and glutarimide copolymers, bisphenol A polycarbonate, aryl-aliphatic copolyamides. Then to analyse, in each polymer series, the effect of chemical structure on mechanical properties and, finally, to relate the latter to the motions involved in the secondary transitions identified in [ 1] (in most cases, the p transition). 

However, the situation is different when we are interested in a series in which the chemical structure of the polymer is gradually changed, as will be the case in this paper when dealing with poly(methyl methacrylate) and its maleimide and glutarimide copolymers (Sect. 3), or with the aryl-aliphatic copolyamides (Sect. 5). In these cases, one can take one of the polymers in the series as a reference and use the corresponding experimental transition temperature for determining the proportionality constant. 

Fig. 10 Optical micrograph showing a pre-crack in polyfmethyl methacrylate-co-N-methyl glutarimide)...

These copolymers will be coded MGIMx, where x indicates the molar % of the glutarimide units in the copolymer. Their Tgs and Tas at 1 Hz are given in Table 4. It is worth noting that Tgs and Tas increase much less with the MGI content than with the CMI unit one (Table 1). Indeed, the CMI cycle is more rigid than the MGI one and, furthermore, the cyclohexyl group of CMI is bulkier than the methyl one of MGI. 

The limited information available in the case of TMBPA-PC, confines the discussion to BPA-PC. However, it is possible to take advantage of the results obtained on poly(methyl methacrylate) and its maleimide and glutarimide copolymers, as described in Sect. 3. Indeed, it has been shown that the development of cooperative motions in the ft transition favours SDZs, relative to CSC s. 

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