Esters methy

Diphenyl-aemicarbazid- malonyb 8 ure-(2)-UhylMt 15, 307. 2-Nitro-phenylbrenztraubenBauie-athyl ester.methy)pbeDylhydra2on 15 II 130-Methyl- [2-nim-phenyl]-brenztraaben anie-ithyleBtec-phenylhydrazon... 

The 1.3-allylic diacetate 135 can be used for the formation of the methy-lenecyclopentane 137 with the dianionic compound 136(86]. The cyclohexa-none-2-carboxylate 138 itself undergoes a similar annulation with the 1,3-allylic diacetate 135 to form the methylenecyclohexane derivative 139(90]. The reaction was applied as a key step in the synthesis of huperzin A[91]. On the other hand. C- and 0-allylations of simple J-dikctones or. 1-keto esters take place, yielding a dihydropyran 140(92]. 

The proeess used is analogous with that adopted for the sjmthesis of eryptopine (p. 298). The methyl ester of JV- -piperonylethyl-3 4-methy-lenedioxyAomophthalamie acid (I), was treated with phosphoryl ehloride and so eonverted into 2 3 9 10-6wmethylenedioxyoxyprotoberberine (II), which was reduced electrolytically to 2 3 9 10-6ismethylene-dioxytetrahydroprotoberberine (III), of which the methochloride (IV) is identical with wodihydroprotopine chloride, which can be prepared from protopine as already stated above. 

Azides can use enamines as dipolarophiles for ],3 cycloadditions to form triazolines. These azides can be formate ester azides (186), phenyl azides (187-195), arylsulfony] azides (191-193,196), or benzoylazides (197,198). For example, the reaction between phenyl azide (138) and the piperidine enamine of propionaldehyde (139) gives 1 -phenyl-4-methy l-5-( 1 -piperidino)-4,5-dihydro-l,2,3-triazole (140), exclusively, in a 53% yield (190). None of the isomeric l-phenyl-5-methyl product was formed. This indicates that the... 

Preparation of J-Methy/ Lumilysergic Acid 8-Methyl Ester-10-Methyt Ether into a suspension of 10 grams of 1-methyi-iumiiysergic acid in 600 cc of absoiute methanoi a stream of anhydrous hydrogen chloride is bubbied for 1.5 hours with strong cooiing. The stream of hydrogen chloride is stopped and the mixture is aiiowed to stand for 30 minutes at 0°C, and is evaporated in vacuo to dryness. The residue is taken up with ice-cooied water made aikaiine with concentrated ammonia and extracted with chioroform. The combined chioro-form extracts are washed first with a 5% aqueous solution of sodium bicarbonate, then with water, and are thereafter dried over anhydrous sodium sulfate and finally evaporated in vacuo to dryness. 

Asymmetric aziridination of a,P-unsaturated esters by use of N-nitrenes was studied in great detail by Atkinson and co-workers [34, 35]. Here, lead tetraacetate-mediated oxidative addition of N-aminoquinazolone 30 (Scheme 3.10) to a-methy-lene-y-butyrolactone 32 was reported to proceed with complete asymmetric indue-... 

Chlor-anilin 4-Methoxy-unilin 4-Amino-benzvesaure-methy /ester 4-Amino-benzonitril... 

As previously discussed, solvents that dissolve cellulose by derivatization may be employed for further functionahzation, e.g., esterification. Thus, cellulose has been dissolved in paraformaldehyde/DMSO and esterified, e.g., by acetic, butyric, and phthalic anhydride, as well as by unsaturated methacrylic and maleic anhydride, in the presence of pyridine, or an acetate catalyst. DS values from 0.2 to 2.0 were obtained, being higher, 2.5 for cellulose acetate. H and NMR spectroscopy have indicated that the hydroxyl group of the methy-lol chains are preferably esterified with the anhydrides. Treatment of celliflose with this solvent system, at 90 °C, with methylene diacetate or ethylene diacetate, in the presence of potassium acetate, led to cellulose acetate with a DS of 1.5. Interestingly, the reaction with acetyl chloride or activated acid is less convenient DMAc or DMF can be substituted for DMSO [215-219]. In another set of experiments, polymer with high o -celliflose content was esterified with trimethylacetic anhydride, 1,2,4-benzenetricarboylic anhydride, trimellitic anhydride, phthalic anhydride, and a pyridine catalyst. The esters were isolated after 8h of reaction at 80-100°C, or Ih at room temperature (trimellitic anhydride). These are versatile compounds with interesting elastomeric and thermoplastic properties, and can be cast as films and membranes [220]. 

CN hexahydro-1-methy 1-4-phenyl-lH-azepine-4-carboxylie acid ethyl ester citrate (1 1)... 

They have developed direct asymmetric synthesis of quaternary carbon centers via addition-elimination process. The reactions of chiral nitroenamines with zinc enolates of a-substituted-8-lactones afford a,a-disubstituted-6-lactones with a high ee through addition-elimination process, in which (5)-(+)-2-(methoxy methy l)pyrrolidine (SMP) is used as a chiral leaving group (Eq. 4.96).119 Application of this method to other substrates such as a-substituted ketones, esters, and amides has failed to yield high ee. 

Limited progress has been achieved in the enantioselective hydrogenation of a,/ -unsaturated carboxylic acid esters, amides, lactones, and ketones (Scheme 26.10). The Ru-BINAP system is efficient for the hydrogenation of 2-methy-lene-y-butyrolactone, and 2-methylene-cyclopentanone [98]. With a dicationic (S)-di-t-Bu-MeOBIPHEP-Ru complex under a high hydrogen pressure, 3-ethoxy pyr-rolidinone could be hydrogenated in isopropanol to give (R)-4-ethoxy-y-lactam in 98% ee [39]. 

Michael adduct.h Reaction over 2.5 h at 55-65°C using cetrimide results in hydrolysis of the ester f 118].c 729b Michael adduct.4 + 13% Michael adduct. 50% 4,5-dichloro-3-methy)pent-3-en-2-one. "Prolonged reaction time. 

Hept-6-en-2-ol, (E) -5 -iso-propyl- 7 - (2-methy-tetrahydro-fur-2-yl) Lf Hept-6-en-2-one, (E)-5-iso-propyl-7-(2-methyl-tetrahydro-fur-2-yl) Lf Hepta-4-(E)-6-dienoic acid, 3-iso-propyl-6-methyl, methyl ester Cured Lf 0.075 Hepta-4-6-dien-l-ol, 3-iso-propyl-6-methyl, (E) Lf ... 

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