Piperonyl alcohol

Under the same conditions, benzaldehyde yielded 80 per cent of benzyl alcohol and piperonal 86 per cent of piperonyl alcohol. 

In a report dated 1915, Mrs Gertrude Maud Robinson (the first wife of Sir Robert Robinson) showed that the acid catalyzed condensation of veratryl alcohol produced, in excellent yield, a solid, m.p. 227 °C, which she considered to be 2,3,6,7-tetramethoxy-9,10-dihydroanthracene [1], In making this proposal (which, however, was not entirely accepted by her husband [1]), she was perhaps influenced by an earlier, hardly justified claim by Ewins (1909) that piperonyl alcohol, under acidic conditions, furnished a high-melting compound similar in many respects to hers described as being with considerable probability 2,3,6,7-dimethyl-enetetraoxy-9,10-dihydroanthracene [2]. 

The substituted benzyl alcohols listed below are prepared in a similar manner from the corresponding aldehydes in the yield indicated vanillyl alcohol, m.p. 113-114°, recrystallized from benzene, 95% anisyl alcohol, b.p. 127-130°/8 mm., 92% piperonyl alcohol, m.p. 52-53°, recrystallized from a mixture of ether and petroleum ether, 91% p-chlorobenzyl alcohol, m.p. 71-72.5°, recrystallized from ben-zene-ligroin mixture, 92% o-chlorobenzyl alcohol, m.p. 64 -65°, 96% p-bromobenzyl alcohol, m.p. 76-76.5°, 96%. 

The principal route of PBO degradation proceeds via an Initial oxidation and hydrolysis at the position of the ethoxy ethoxybutoxy side chain leading to the formation of MDB alcohol, also referred to as piperonyl alcohol. This undergoes further oxidation, through MDB aldehyde, to MDB acid. This acid, also referred to as pipcnunylic acid (Kamienski and Casida, 1970). was detected as a metabolite in the urine of mice, either as the free acid or conjugated. It has also been confirmed as a metabolite in the rat (Lin and Selim, 1991 Selim, 1991), where it accounted for c. 3% of the applied dose in both urine and faeces. 

Piperonyl alcohol (0.15 g, 1.00 mmol) was dissolved in EtOAc (7 mL, 0.14 M final concentration), and l-hydroxy-l,2,benziodoxol-3(l/7)-one (IBX 0.84 g, 3.00 imnol) was added. The resulting suspension was immersed in an oil bath set to 80 °C and stil l ed vigorously open to the atmosphere. After 3.25 h (TLC monitoring), the reaction was cooled to room temperature and filtered through a medium glass frit. The filter cake was washed with 3x2 mL of EtOAc, and the combined filtrates were concentrated to yield 0.14 g (90%, > 95% pure by H NMR) of piperonal as a waxy solid. 

In 1988 and 1990, Fuchs reported a new approach to the synthesis of the Cephalotaxus alkaloids ( )-cephalotaxine (1) (30,31), ( )-ll-hydroxyceph-alotaxine (26) (31), and ( )-drupacine (28) (31), which was based on the exploitation of vinyl sulfones as convenient multifunctional synthons (Schemes 7 and 8). The synthesis of cephalotaxine (Scheme 7) began with the ortho ester 77, obtained from piperonyl alcohol in five steps, which was... 

According to AF values, the rate of the polymerization decreases in the order of 3,4-dimethoxybenzyl alcohol > piperonyl alcohol > 4-methoxylbenzyl alcohol >... 

The major product, des base D, formed an 0-acetyl derivative and was converted to a deoxy compound F on catalytic reduction. Des base D formed no carbonyl derivatives, but permanganate oxidation afforded a mixture of 6-(4-methoxyphenyl)piperonal and 6-(4-methoxyphenyl)-piperonylic acid, the structures of which were confirmed by unambiguous synthesis (134). It follows that des base D is 6-(4-methoxyphenyl)-piperonyl alcohol (CXXVI) (117, 136, 137). The analytical data and melting point of 0-acetyl des base D agree with those reported for des base C, and it is likely that they are identical (137). The hydrogenation product of des base D, deoxy compound F, has been identified as 4 -methoxy-3,4-methylenedioxy-6-methylbiphenyl (134). 

Piperonyl alcohol 328 2-Propanol is rendered anhydrous by 4 hours boiling with calcium oxide, distillation, further boiling with aluminum isopropoxide, and renewed distillation. 50 g of piperonal in 500 ml of this alcohol are treated with 10 g of aluminum isopropoxide, and the whole is heated in an oil-bath at 95° under a Widmer column attached to a descending condenser. At the end of this time, 200 ml of distillate have passed over (b.p. 77-81°) and acetone is no longer detectable in a sample by means of 2,4-dinitrophenylhydrazine in N-hydro-chloric acid. The residue is treated with water, made just acid with hydrochloric acid, and extracted with ether. The extract is dried and evaporated, and the residue is distilled in a vacuum, giving 45 g of a product of b.p. 151°/13 mm. This solidifies to crystals melting at 51°. 

Klungsoyr, J. Scheline, R.R. (1984) Metabolism of piperonal and piperonyl alcohol in the rat with special reference to the scission of the methylenedioxy group. Acta Pharm. Suec. 21,67-72. 

Typical substrates oxidized are p-nitro- and p-methoxybenzyl alcohol, geraniol, myrtenol, 2-cyclohexenol, cinnamyl alcohol, piperonyl alcohol and -hex-2-en-l-ol [32]. 

SEQUENCE E The Synthesis of Piperonylonitrile from Piperonyl Alcohol 493... 

The first step in this sequence of reactions is the oxidation of piperonyl alcohol to obtain piperonal, an aromatic aldehyde. The reaction is selective and only the aldehyde is obtained no oxidation to the carboxylic acid is observed ... 

---