3.3- Dimethylglutaric anhydride

Robins and Sakdarat have achieved the first reconstruction of an eleven-membered macrocyclic pyrrolizidine diester (43).16 Treatment of (+)-retronecine (13) with 3,3-dimethylglutaric anhydride gave a mixture of the 7- and 9-monoesters of (+)-retronecine. Intramolecular lactonization of this mixture via... 

The condensation of the 2,3-diaminopyridine (286) with 3,3-dimethylglutaric anhydride (287) in refluxing acetic acid afforded the 2-substituted imidazo[4,5-6]pyridine (288) in good yield (Scheme 28) (94JHC73). Compound (288) may also be prepared by the initial condensation of the pyridine (286) with the aldehyde (289) in the presence of acid to produce an intermediate Schiff base which on oxidation with iodine in 1,2-dimethoxyethane gives compound (290) which was hydrolyzed to the acid (288) <93JMC1175>. The yield in this reaction sequence was less than that from the condensation using the anhydride (287). 

The synthesis in Scheme 13.40 features a catalytic asymmetric epoxidation (see Section 12.2.1.2). By use of me30-2,4-dimethylglutaric anhydride as the starting material, the proper relative configuration at C(4) and C(6) is ensured. The epoxidation directed by the (+)-tartrate catalyst controls the configuration established at C(2) and C(3) by the epoxidation. Although the epoxidation is highly selective in... 

C7H9NO 3-amino-5-methyl phenol 76619-89-1 26.71 1.0723 2 11192 C7H10O3 2,2-dimethylglutaric anhydride 2938-48-9 25.56 1.0731 2... 

On the basis of the significant kinetic isotope effect (kMeOH/ MeOD = 2.3) in the cinchonine (1, 10 mol%)-catalyzed ring opening of cis-2,4-dimethylglutaric anhydride by methanol (20 equiv) in toluene, Oda proposed the general base catalysis mechanism depicted in Scheme 11.5 [3a, b]. Another comparative study on the reaction rates (k0bs) obtained with different bases (cinchonidine (2.26 x 10-3), quinuclidine (2.26 x 10 3), and quinoline (4.34 x 10-5)) and with different... 

A soln. of 2-pyridylhydrazine in benzene added dropwise with stirring to dimethylglutaric anhydride in benzene crude, y -dimethylglutaric mono-(2-pyridyl)hydrazide (Y 77%) heated 5 min. at 150° then slowly to 210°, and the product isolated after 20 min. l-(2-pyridylamino)-4,4-dimethylglutar-imide (Y 71%). F. e. s. J. Btichi et al., Helv. 45, 449 (1962). 

C7H8O3, 6,7-endo-Epoxy-2-oxabicyclo[3.3 0]octan-3-one, 45B, 318 C7H,o03, meso-2,4-Dimethylglutaric anhydride, 46B, 305 C7H11BF8O2, endo-2-Methyl-cis-4,5-trimethylene-l,3-dioxolan-2-ylium tetrafluoroborate, 45B, 318... 

These results may be compared with those of the experiments of Schwartz and Carter (64) and Cohen (65a) with fl-phenylglutaric anhydride. [See also the more recent results of Fujita and co-workers with meso-2,4-dimethylglutaric acid (65b).] The former group showed that a chiral amine could discriminate between attack at the pro-(/J) and pro-(S) carbonyl groups of the anhydride. The two diastereomers were formed in a ratio of 3 2, with optical purities of about 20%. 

The anhydride of a,a-dimethylglutaric acid was reacted with thiophen under Friede1-Crafts condition to give (72), which after Clemmensen reduction was ring-closed to (73) upon treatment with PPA.3 3... 

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