Ueber Acetyllävulinsäure und die Constitution der γ‐Ketonsäuren

Abstract

Acctyllaviiliiisiiure und die Constitutioti der y-Ketot isiiuren ; von J. Bred. (Mittheilung nun dem dhemischen Inetitut der' Unirern'tllt Bonn.) (Eingelaufen den 21. Scptcmber 1886.) Die Liivulinsaure ist bislier allgeniein als das Anfapgsglied der y-Ketonsauren betruchlet uiid die ihr zugeschriebene Constitutionsformel ; von kciner Seite bezweifclt wordea. Bedenkt man jedoch die aufserordentliclie Neigung zur Lactonbildung , welche wiederkehrt , so o n Jer Curboxylgruppe Celegenheit zur Ringschliefsung uii eineni Iiolilenstaffatom in der y-Stellung geboten wird, so nrufs man jedcnfalls der MBglichkeit Hechnung trugen, dafs cine derdrlige y-Ketonsaure sich in das entsprechende Oxylacton von der Fornrel : CLI,CO. CH, . CIA*. COOH CH,C(OH). CH,. CH, LO I 0

Ring-Chain Tautomerism.

“…On the simple basis of chemical behavior alone, it would be assigned the chain structure in the former case; the ring structure in the latter. An acid such as levulinic acid, which forms both derivatives (12,50,129), is considered to be a mixture of ring and chain tautomers, and it is often presumed that the relative amounts of the two derivatives serve as an indication of the amounts of ring and chain tautomers in the starting acid. This method of analysis may lead to erroneous results for at least two reasons.…”

Pseudoacids. I. 4- and 5-Oxoacids

“…Oxoacids may be thought to be analogous to the Y-and 8-hydroxyaldehydes/-ketones (carbohydrates) with the salient functional groups each in the next higher carbon oxidation state. The parent cyclic acids were named 'pseudos~iure' (pseudoacid)., For the 4-ketoacids, the cyclic form of levulinic acid (4oxopentanoic acid) was recognized more than a century ago as the potential intermediate in its acid-promoted dehydration to a-angelica lactone (Bredt, 1886). In solution, levulinic acid exists in the open form, although substitution at the positions between the carbonyls apparently shifts the solution equilibria toward the cyclic forms (Pascual et al, 1964;Claeson & Thalen, 1967).…”

Acetoxy-γ-valerolactone

“…For hydrogenbonding motifs, see: Bernstein et al (1995). For background information, see: Bredt (1886); Rasmussen & Brattain (1949); Suami & Day (1959); Glenny et al (2012). For a previous description of the title compound but without supporting crystal structure data, see: Bell & Covington (1975).…”

“…Acetoxy-γ-valerolactone (2-methyl-5-oxotetrahydrofuran-2-yl acetate) was first described by Bredt (1886) and became of interest during our investigation of novel, renewable levulinyl cellulose esters. Esterification of cellulose in the presence of levulinic acid and an aliphatic anhydride affords a mixed cellulose levulinyl ester which we have shown has particular utility in architectural coatings [Glenny et al, 2012].…”