Butanolids

A lactone is named by replacing the oic acid ending of the parent carboxylic acid by olide and identifying its oxygenated carbon by number This system is illustrated m the lactones shown m the preceding equations Both 4 butanolide and 5 pentanolide are... 

In a similar experiment, unlabeled 4-butanolide was allowed to stand in an acidic solution in which the water had been labeled with 0. When the lactone was extracted from the solution after four days, it was found to contain 0. Which oxygen of the lactone do you think became isotopically labeled ... 

Bernsteinsaure-imide werden zu 4-Hydroxy-butansaure-amiden reduziert2 3, wobei auch hier 4-Butanolide anfallen2. 

Zu einer Suspension von 0,275 g (2 mMol) 2-Formyl-4-butanolid-Natriumsalz, 0,325 g (4 mMol) Dimethyl-amin-Hydrochlorid und 0,25 g Linde 3 A Molekularsieb gibt man 0,13 g (2 mMol) Natrium-cyano-trihydrido-borat und riihrt 24 Stdn. Danach filtriert man iiber Celite, wascht mit 10 ml Methanol und sauert das Filtrat mit... 

At this time, we can focus on the creation of the butenolide. Sulfur based methodoly allows simplification to the simple butanolide as in 170. While cyclobutanone spiroannulation of 171 followed by a Baeyer-Villiger reaction would create 170,... 

The availability of cyclopentenones from butanolides allows the lactone annulation to facilitate the synthesis of cyclopentyl natural and unnatural products. An example that highlights the latter is dodecahedrane (178) for which 179 constitutes a critical synthetic intermediate 136,137). Lateral fusion of cyclopentenones as present in 179 can arise by acid induced reorganization and dehydration of 180. While a variety of routes can be envisioned to convert a ketone such as 182 into 180, none worked satisfactorily137 On the other hand, the cyclobutanone spiro-annulation approach via 181 proceeds in 64 % overall yield. Thus, the total carbon cource of dodecahedrane derives from two building blocks — cyclopentadiene and the cyclopropyl sulfonium ylide. 

In addition, other systems of nomenclature for AHLs have also appeared in the literature describing them as derivatives of furanone, y-butyrolactone or 4-butanolide. For example, the above V.fischeri autoinducer can also be named as (S)-N-(3-oxohexanoyl)-3-aminodihydro-2(3H)-furanone,(S)-a-(3-oxohexa-noyl)amino-y-butyrolactone or (S)-2-(3-oxohexanoyl)amino-4-butanolide (another IUPAC name) [27]. 

Intramolecular addition can occur when nucleophilic substituents are suitably positioned as in Eq. 14 [88]. When the latter electrolysis is conducted in CH2CI2/BU4 NCI, 75% of the chloro-y-lactone are obtained. Electrolysis of ( )-5-phenyl-4-pentenoic acid affords a 4-(phenyl-methoxymethyl) -4-butanolide [89]. 

Ester Aldehyde or Ketone Butanolide Product Yield /%... 

Antibiotic production and morphological differentiation (formation of aerial mycelium and sporulation) in Streptomyces species and in some other actinomycetes is regulated by small signaling molecules called y-butyrolactones or butanolids. These quorum-sensing signals bind to... 

Chiral furanones (butanolides) such as 191 have been used as dipolarophUes in various 1,3-dipolar cycloadditions. The chiral 4-substituted butanolide 190 was prepared from 191 and the chiral auxiliary menthol (Scheme 12.55) (310,311). The single diastereomer 191 is obtained by crystallization and epimerization of the other diastereomer, as the amount of 191 in solution decreases. 1,3-Dipolar... 

S )-3-Hydroxy-4-butanolide (1), which is readily available from (—)-(S)-malic acid, can be converted into the dianion and the latter alkylated with alkyl halides or mesylates with moderate yields but with high diastereoselectivity (d.r. >98 2)39. 

Auf ahnliche Weise wird aus 3-Amino-2-oxo-tetrahydrofuran (2-Amino-4-butanolid) 4-(2-Hydroxy-ethyl)-2-mercapto-imidazol hergestellt149. 

Morino, A., Kuwahara, Y., Matsuyama, S. and Suzuki, T. (1997). ( ,)-2-(4/-Methyl-3 -pentenylidene)-4-butanolide, named /i-acariolidc a new monoterpene lactone from the mold mite, Tyrophagus putrescentiae (Acarina Acaridae). Bioscience, Biotechnology and Biochemistry 61 1906-1908. 

SCHEME 65. BINAP-Ru-catalyzed hydrogenation of 2-acetyl-4-butanolide. 

Scheme 65 shows a reaction occurring with opposite 2,3-syn diaste-reoselection. Hydrogenation of racemic 2-acetyl-4-butanolide, in which the 2-substituent and directing group are linked, proceeds with 98 2 yn anti selectivity to form the diastereomeric hydroxyethyl lactones. 

The butanolide and butenolide lactones are formally furans with exocyclic double bonds and are sometimes indexed in this manner. Their chemistry, however, is not customarily related to furan chemistry but simply to acyclic ester chemistry. Lactones of course have the CC-cis rather than the CC-trans conformation (36JCS1383), but the atoms defining the... 

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