Coupling reaction between 4-t-butyl-o-benzoquinone and methyl linoleate

Abstract

this reagent and were discarded; fractions 4-11, which reacted positively with the F1 reagent were combined and the benzene removed in vacuo. Recrystallization of the crude white crystalline solid, so obtained, from light petroleum (b.p. 80-100") gave 6-acetoxy-4-S-carboxymethylthio-5-hydroxy-1,7-dimethylindole lactone (10) as white needles (53 mg, m.p. 202-204'). The proton magnetic resonance spectrum of this product in CDCI, indicated the presence of two C-CH, groups at z 7.62 and 7.45; an S-CHZgroup at z 6.54; an N-CH, group at z 5.98; the indole P-proton at z 3.64 (J,,, = 3 Hz); and the indole a-proton at z 3.03 (JZe3 = 3 HZ).Anal. Calcd. for C14H13N04S: C, 57.80; H, 4.50; N, 4.81; S, 11.02. Found: C, 57.61; H, 4.36; N, 4.85; S, 10.69. G. N. COHEN. Compt. Rend. 220, 796 (1945 This is the first report on the dehydrogenation-coupling reaction of an o-quinoid compound with a 1,Cdiolefinic compound. The reaction of 4-t-butyl-o-quinone and methyl linoleate has been studied, and the product which has a 1-(2'-hydroxy-4'(or 5')-t-buty1phenoxy)-2,4-pentadienyl structure has been separated and identified.Canadian Journal of Chemistry, 47, 2106Chemistry, 47, (1969 Previously we reported that urushiol quinone reacts with the side chain of a triolefinic component of urushiol (3-(8', 1 1',1 3'-pentadecatrieny1)-catechol) during the laccase-catalyzed oxidation process of Japanese lacquer, giving a coupling product with a phenyl ether linkage and a conjugated triene structure (1). As a further example of this type of reaction, we now describe the formation of a coupling product (1) in the reaction of 4-t-butyl-o-quinone with methyl linoleate at room temperature. R1 = t-butyl attached to 4 or 5 position Rz = (CHZ)7--COOCH3 3 -(CH2)4--CH3 andlorConcerning the reactions of o-quinones with unsaturated hydrocarbons, it is known that ahigh potential o-quinone, e.g., tetrachloro-o-quinone, abstracts hydrogen from the latter (2,3). It has been also reported that hydroquinone a-tetralyl ether derivatives were obtained by the reaction between the high potential p-quinone derivatives and tetralin ( 4 3 . In those cases, however, an elevated temperature (4) or a radical initiator (5) was required. Therefore, this is the first report on the dehydrogenation-coupling reaction of an o-quinone with a 1,Cdiene system.The reaction product (1) was separated by thinlayer chromatography (t.1.c.) and identified. The results of the elemental analysis and the molecular weight measurement indicate that the compound is a coupling product between methyl linoleate and 4-t-butyl-o-quinone. The presence of a hydroxyl group and a benzene nucleus is obvious in view of the finding of the infrared (i.r.) absorptions at 3600-3200 cm-', and at 1599 and 1510 cm-I, respectively. The conjugated diene structure was identified by the ultraviolet (u.v.) and i.r. absorptions at 234 mp ( E 27 900) and 991 Can. J. Chem. Downloaded from www.nrcresearchpress.com by 54.244.106.145 on 05/12/18For personal use only.