Butyrolactone, opening

Rea.ctlons, Butyrolactone undergoes the reactions typical of y-lactones. Particularly characteristic are ring openings and reactions in which ring oxygen is replaced by another heteroatom. There is also marked reactivity of the hydrogen atoms alpha to the carbonyl group. 

Frequendy unique and synthetically usehil are a series of ring-opening reactions. Butyrolactone and anhydrous hydrogen haUdes give high yields of 4-halobutyric acids (164). In the presence of alcohols, esters are formed. 

Other methods include ring opening of parasorbic acid [108-54-3] (5-lactone of 5-hydroxy-2-hexenoic acid) in hydrochloric acid or in alkaline solutions (43,44), the ring opening of y-vinyl- y-butyrolactone in various catalysts (45,46), or isomerization of 2,5-hexadienoic acid esters (47,48). Other methods are described in thehterature (6,49,50). 

Figure 10. Integrated irreversible capacities of LiC in y-butyrolactone based electrolytes without (full symbols) and with (open symbols) C02 as electrolyte additive using various electrolyte salts LiCl04 (top, left), LiBF4 (top, right), LiPF6 (bottom, left), LiN(S02CF3)2 (bottom, right). Carbon Lonza KS44 synthetic graphite, i = 10 pA mg 1, cut-off 0-1.5 V vs. Li/Li+ [12],...

Cyclic carbonates have been prepared in the regiospecific ring-opening of oxiranes by butyrolactones catalysed by the quaternary ammonium salt (Scheme 3.6)... 

Figure 3. Changes in open circuit potential (OPC) with temperature for post-thermally treated BAO panels, Barex 210/N-vinylpyrrolidone (B210/NVP) and Barex 210/gamma-butyrolactone (B210/GBL) photocured coatings on BAO panels.

Ajellal N, Thomas CM, Carpentier J-F (2009) Functional syndiotacticpoly(P-hydroxyalkanoate)s via stereoselective ring-opening copolymerization of rac-P-butyrolactone and rac-allyl-P-butyrolactone. J Polym Sci A Polym Chem 47 3177-3189... 

Ajellal N, Bouyahyi M, Amgoune A, Thomas CM, Bondon A, Pillin I, Grohens Y, Carpentier J-F (2009) Syndiotactic-eirriched Poly(3-hydroxybutyrate)s via stereoselective ring-opening polymerization of racemic (3-butyrolactone with discrete yttrium catalysts. Macromolecules 42 987-993... 

Five-membered lactones (y-butyrolactones) fused to carbohydrates have proven to be convenient synthons towards branched-chain sugars through opening of the lactone unit. Velaskes et al. [208] described the synthesis of y-butyrolactones... 

A similar spiro-fused starting material was prepared to study the thermolysis of a 1,3-dioxane analog. As found for the dithia compound (cf. Section 8.11.6.3.1), a carbene-derived dimer was formed as the major detectible product (20%) <2002TL1927>. Other products, such as tricycle 185, have been identified in subsequent studies <2004CJC1769>. However, phenyl substitution at G-4 provided completely different thermolysis products, probably via formation of an open-chain bis-radical. Thus, 3-phenyl-7-butyrolactone and, after CO2 extrusion, phenylcyclo-propane are the major reaction products (Scheme 58) <2002CJC1187>. 

Ring-opening copolymerization (ROP) of (R)-/3-butyrolactone with (R)-3-methyl-4-oxa-6-hexanolide in the presence of tin(iv) chloride affords a new biodegradable copolymer (Equation 1) <1995MM406>. 

Solvents that meet all or most of the criteria are propylene carbonate, dimethyl sulfoxide, 4-butyrolactone, acetonitrile, sulfur dioxide, thionyl chloride, and phosphorus oxychloride. Certain other solvents, with fairly low s values, such as tetrahydrofuran, dimethoxyethane, and 1,3-oxolane are used in conjunction with a high s solvent, in order to reduce the viscosity without impairing excessively the other desirable properties of the co-solvent. All these solvents are on the List, with properties shown in the tables mentioned. Commercial implementation of such batteries has been highly successful, with energy densities of primary dischargeable batteries of 0.3 W h g 1 or 0.5 W h cm 3 and a self discharge rate of < 2% per year of the open-circuit battery being achieved. 

Free radical polymerization of cyclic ketene acetals has been used for the synthesis of polyfy-butyrolactone), which cannot be prepared by the usual lactone route due to the stability of the five-membered ring. The polymerization of 2-methylene-l,3-dioxalane at high temperatures (above 120 °C) gave a high molecular mass polyester [59,79]. Only 50% of the rings opened when the polymerization was carried out at 60 °C, and this led to the formation of a random copolymer. The presence of methyl substituents at the 4- or 5-position facilitated the reaction. The free radical initiators generally used in such polymerizations are ferf-butyl hydroperoxide, ferf-butyl peroxide, or cumene hydroperoxide. The various steps involved are described in Scheme 5 [59]. 

It was shown early on by Kende and co-workers that isosteganone 81 can be thermally isomerized to steganone 12, Fig. (17) [109]. This operation does not involve simple biaryl bond rotation since isosteganacin is unable to isomerize thermally to steganacin. It occurs rather through ring opening of the butyrolactone to form intermediate A, which... 

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