A-Butyrolactone

In addition to its water solubility poly(vinyl pyrrolidone) is soluble in a very wide range of materials, including aliphatic halogenated hydrocarbons (methylene dichloride, chloroform), many monohydric and polyhdric alcohols (methanol, ethanol, ethylene glycol), some ketones (acetyl acetone) and lactones (a-butyrolactone), lower aliphatic acids (glacial acetic acid) and the nitro-paraffins. The polymer is also compatible with a wide range of other synthetic polymers, with gums and with plasticisers. 

Oxidative decomplexation of the dialkylated organic ligand to provide a butyrolactone is accomplished by successive treatment of the cationic carbene complex with hydroxide followed by bromine96. 

The sesquiterpene (+)-asteriscanolide 1 was first isolated from Asteriscus aquaticus L and characterized by San Feliciano in 1985.1 It has captured the attention of organic chemists mainly because of its uncommon bicyclo[6.3.0]undecane ring system bridged by a butyrolactone fragment. The only prior enantioselective synthesis of 1 has been described by Wender in 1988 featuring an Ni(0)-promoted [4 + 4]-cycloaddition.2 Booker-Milburn and co-workers described the sequential application of intramolecular [2 + 2]-photocycloaddition, Curtius rearrangement, and oxidative fragmentation to produce the 7-desmethyl derivative in 1997.3... 

Other lactones detected include a-butyrolactone and pantolactone (2,4-hydroxy-3,3-dimethylbutyrolactone), both of which are typical of sherries. Besides the duration of aging, their concentration is closely linked to yeast strain (Zea et al., 1995). Another lactone, solerone (4-... 

Other lactones detected include a-butyrolactone and pantonolactone (2,4-dihyd-roxy-3,3-dimethylbutyrolactone), which is deemed typical of sherry wines. Both have been associated with specific yeast races (Zea et al. 1995) and the aging time (Cortes 2002). 

SYNS Y-(3480 Y-BL BLO BLON BUTYRIC ACID LACTONE a-BUTYROLACTONE Y-BUTYROLACTONE (FCC) BUTYRYL LACTONE 4-DEOXYTETRONIC ACID DIHYDRO-2(3H)-FURAN-ONE FEMA No. 3291 4-HYDROXYBUTANOIC ACID LACTONE Y-HYDROXYBUTYRIC ACID CYCLIC ESTER 4-HYDROXYBUTYRIC ACID Y-LACTONE Y-... 

An interesting recent case of a solvolytic study of a fused-ring cyclopropylcarbinyl system is that of Hudrlik and coworkers on 38 as part of a synthesis of a-methylene-a-butyrolactones. 

Further biotransformations of A" VPA involve both the liver microsomal CYP enzymes and the fatty acid (3-oxidation pathway (Figure 33.29). The mixed-function-oxidase system metabolizes the unsaturated metabolite to a -butyrolactone derivative through a chemically reactive entity that is a mechanism-based inhibitor of CYP. The alkylation of the prosthetic heme by means of the radical occurs prior to formation of the epoxide. Thus, the epoxide is not involved in the CYP inhibition. 

Trachelogenin (39) showed the most potent activity, IC50 1.1 x 10 M while arylnaphthalenes showed no significant activity [80]. Several mammalian lignans containing a butyrolactone group—enterolactone (118), 3-0-methylenterolactone... 

As shown in section 2.1.1 and figure 15, (-t-)-muricatacin 19 has been synthesized in 4 steps and 48 % overall yield from a very inexpensive starting material, L-glutamic acid. The key steps of the synthesis are a nitrous deamination of an a-amino acid with retention of the configuration of the stereogenic centre, and a very diastereoselective reduction of a-butyrolactonic ketone 18 with L-Selectride . The use of D-glutamic acid allowed the preparation of (-)-muricatacin 19 as well. 

Tochtermann s strategy was based on a diastereoselective reduction of a racemic a-butyrolactonic ketone 124, followed by a chemical resolution in order to obtain a homochiral synthon 129 which after further chemical transformations led to the desired compound, (-)-muricatacin 19 (Fig. 16). The synthesis has been achieved in 17 steps and each transformation ranging from 77 to 97 % yield. 

Butyric acid lactone 4-Butyrolactone a-Butyrolactone y-Butyrolactone Butyryl lactone 4-Deoxytetronic acid Dihydro-2(3H)-furanone... 

Hashimoto K, Nihira T, Sakuda S, Yamada Y. IM-2, a butyrolactone autoregulator, induces production of several nucleoside antibiotics in Streptomyces sp. FRI-5. J Ferment Bioeng 1992 73 449 55. 

Sakuda S, Higashi A, Tanaka S, Nihira T, Yamada Y. Biosynthesis of virginiae butanolide A, a butyrolactone autoregulator from Streptomyces. J Am Chem Soc 1992 114 663-668. 

Okatnoto S, Nihiia T, Kataoka H, Suzuki A, Yamada Y. Purification and molecular cloning of a butyrolactone autoregulator receptor from Streptomyces virginiae. J Biol Chem 1992 267 1093-1098. 

The herbicidal activity of sulfonylureas derived from phenylacetic esters is enhanced when the carboxylate moiety is tied up to form a butyrolactone ring. Extension of this structural modification to weakly herbicidal sulfonylureas derived from cinnamate esters gives vinylogous butyrolactones which display significantly improved efficacy. Structure-activity relationships in these two classes of compounds are discussed along with their synthesis involving a novel benzothiazinone dianion and rf/h9-metallation chemistry. 

Acetic acid, on interaction with Mn-III-acetate [174] or other one-electron-oxidation agents of similar oxidation potential such as Cer-IV- [175] or Vanadium-V-salts, forms a radical, which in the presence of the diene 93 is trapped to form a butyrolactone 108 [176,177] (Reaction scheme 64). This lactone can be transformed into permethric acid as described in Sect. 1.3.2.2. 

Bibb 2005 Martin and Liras 2010). We will refer to the well-known streptomycin and cephamycin/clavnlanic acid regnlatory cascades as model systems, but the tylosin regulatory cascade and other similar cascades are also well known (Cundliffe 2008). In all these cases the top position in the regulatory cascade is occupied by (i) a butyrolactone receptor protein (BRP) in coordination with its cognate butyrolactone molecnle (Takano 2006), or (ii) a pleiotropic regulator (e.g. AreB dgR) that governs butyrolactone biosynthesis, and therefore, the butyrolactone-dependent cascade. 

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