Maleic anhydride 2-methyl derivative

Similarly, proximate-parallel bishydrazine 442 can be transferred to 443 by direct acylation with maleic anhydride. Analogous derivative 445 can be obtained from the same starting compound by treatment with methyl 3,4-epoxy-butanoate to provide 444, followed by mesylation and elimination of the intermediate mesylate (Scheme 73) <2005EJ01311>. 

In this paper a generalized approach is presented to the derivation of H-H-S equations for multispecies polymers created by addition polymerization across single double bonds in the monomers. The special cases of copolymers and terpolymers are derived. This development is combined with experimental results to evaluate the numerical parameters in the equations for poly(styrene-acrylonitrile ) (SAN) in three separate solvents and for poly(styrene-maleic anhydride-methyl methacrylate) (S/HA/MM) in a single solvent. The three solvents in the case of SAN are dimethyl formamide (DMF), tetrahydrofuran (THF), and methyl ethyl ketone (MEK) and the solvent for S/HA/HH is HER. 

Chitanu, G.C., Popescu, I. Carpov, A. (2007). Synthesis and Characterization of Maleic Anhydride Copolymers and Their Derivatives. 3 Synthesis and Characterization of Maleic Anhydride-Methyl Methacrylate Copolymers. Revue Roumaine de Chimie, Vol. 52, No. 1-2, (January - February 2007), pp. (135-141), ISSN 0035-3930... 

Poly(methyl vinyl ether-i o-maleic anhydride) and their monoalkyl ester derivatives have been shown on rabbits to be neither primary irritants nor primary sensiti2ers to skin and eyes. The acute oral toxicities on white rats of the two copolymers are, respectively, 29 g/kg and 25 g/kg body weight. 

Ethoxy)-allylidenecyclopropane (136a) readily underwent Diels-Alder reaction with activated dienophiles under mild conditions (Table 14) [33]. Only one regioisomer was formed with unsymmetrically substituted dienophiles such as methyl maleic anhydride (137), and quinones 138-141 (entries 2 and 3-6). AH the cycloadducts 143-147 derive from an endo approach between the two reagents. Two site-isomers were obtained in 96 4 ratio with 3-isopropyl-6-methyl-p-quinone (141) (entry 6) and the high site-selectivity observed in this... 

In Scheme 39, new pathways to fused [l,4]thiazines are shown. The oxadiazolone derivative with a mercapto-methyl side chain (308) was reported to react with maleic anhydride to the fused product 309 in high yield <1996M549>. The acetylene substituted triazole 310, when reacted with 2molarequiv of phenylisocyanate, afforded a polysubstituted triazolothiazine derivative 311 via a fairly complicated reaction pathway <1998CJC635>. 

However, treatment of 109a-d with maleic anhydride leads to the appropriately substituted 0x0 derivatives llla-d <1998T5753>. 6-Aminouracil and the iV-methyl or -dimethyl analogs proceed under identical conditions to form the corresponding iV-methylated analogs of 111 <1998T5753>. 

The pioneer work on this subject using simple 1-azadienes is due to Ghosez et al. (82TL3261 85JHC69) they succeeded in reacting 1-azadienes as 47r-electron components in Diels-Alder cycloadditions. Thus, l-dimethylamino-3-methyl-l-azabuta-l,3-diene (a,/3-unsaturated hydrazone) 54 did undergo [4 + 2] cycloaddition to typical electron-poor dienophiles, e.g., methyl acrylate, dimethyl fumarate, acrylonitrile, maleic anhydride, and naphthoquinone, producing pyridine derivatives 55-57 (Scheme 14). 

The parent compound (4), a derivative of o-quinodimethane, is unstable in solution it reacts almost instantaneously with typical dienophiles like maleic anhydride and methyl vinyl ketone to give the corresponding Diels-Alder adducts (Section III). Simple HMO calculations show that the total ji-electron energy of 4 is smaller than that of benzo[h]furan (8). It can be... 

Dibenzofuro[4,5-c]tropone (8H-dibenzo[a,e]furo[3,4-c]cyclohepten-8-one 368, X = CO) and the corresponding thiepin-5,5-dioxide (8//-dibenzo-[6,/]furo[3,4-retro Diels-Alder route. In refluxing benzene, the intermediate (367, X = CO) can be isolated. Further routes to 368 (X = CO) by retro Diels-Alder reaction exist. The 1-methyl derivative of 368 (X = CO) has been trapped as a maleic anhydride adduct. ... 

H- 1,3-oxazine was obtained along with the 3,4-dihydro derivative as previously described190 [Eq. (44)]. When methyl isocyanate (R = Me) was used for cyclization, only the 2,3-dihydro derivative resulted, along with the azetidinone [Eq. (44)]. Halogenated 2,6-dioxo derivatives were obtained by reacting trimethylsilylazide with halogenated maleic anhydride.192... 

Tetrahydro derivatives, such as compounds 156-158, some possessing biological activity, have been prepared by the routes shown in Eqs. (20)-(22).216-219 Another compound with a reduced pyrrole ring is the product obtained from the reaction of Ar-methyl-2-pyridone with maleic anhydride, formulated as the (unlikely) structure 159. It is very labile, dissociating to Ar-methyl-2-pyridone and maleic acid in polar solvents.220... 

Abbreviations arene, i/6-benzene or substituted benzene derivative bipy, 2,2 -bipyridyl Bu, Bu", Bu, iso-, n-, or rerf-butyl COD, 1,5-cyclo-octadiene Cp, /5-C5H5 DAD, dimethyl-acetylene dicarboxylate dam, 1,2-bis(diphenylarsino)methane DBA, dibenzylideneacetone DMF, A. A -dimethylformamide dpe, l,2-bis(diphenylphosphino)ethane dpen, os-l,2-bis(di-phenylphosphino)ethylene dpm, 1,2-bis(diphenylphosphino)methane ESR, electron spin resonance F6-acac, hexafluoroacetylacetone FN, fumaronitrile MA, maleic anhydride Me, methyl MLCT, metal ligand charge transfer phen, 1,10-phenanthroline Pr , Pr", iso- or n-propyl py, pyridine RT, room temperature TCNE, tetracyanoethylene tetraphos, (Ph2PCH2CH2)jP THF, tctrahydrofuran Xylyl, 2,6-Me2C6H3. 

There is no easy and/or effective method for the preparation of 1,2,3,4-tetrasubstituted naphthalenes starting from a simple naphthalene derivative and based on classical substitution methodology. A clever new route, based on the now common concept of "tandem" reactions, is illustrated as follows. Heating of the sulfoxide 1 with acetic anhydride at 120°C in the presence of maleic anhydride gave an adduct 2, C20H16O4S, in 87% yield as a mixture of diastereomers. Reaction of the adduct 2 with PTSA in THF at 25°C gave the naphthalene derivative 3 in quantitative yield. Use of methyl propiolate in place of maleic anhydride did not result in isolation of an adduct the product was the tetralone 4 (51%). 

Maleimide also forms 2 1 adducts with acceptor compounds such as benzonitrile, acetophenone, and methyl benzoate [46], This behavior contrasts with that of maleic anhydride, which neither exhibits charge-transfer absorption with nor photoadds to benzenes bearing strong electron-acceptor substituents. It clearly demonstrates that formation of a ground-state charge-transfer complex is not essential in the formation of 2 1 adducts from maleimide and benzene derivatives. 

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