Lilac Alcohol Research Articles

Analysis of volatile compounds emitted from fresh Syringa oblata flowers in different florescence by headspace solid-phase microextraction–gas chromatography–mass spectrometry

In this study, a simple and solvent-free method was developed for determination of the volatile compounds from fresh flowers of Syringa oblata using headspace solid-phase microextraction and gas chromatography–mass spectrometry. The SPME parameters were studied, the optimum conditions of a 65 μm polydimethylsiloxan/divinylbenezene (PDMS/DVB), extraction temperature of 25 °C and extraction time of 30 min were obtained and applied to extraction of the volatile compounds emitted from fresh flowers of S. oblata. The volatile compounds released from fresh flowers of S. oblata were separated and identified by GC–MS. Lilac aldehyde A, lilac aldehyde B, lilac aldehyde C, lilac aldehyde D, lilac alcohol A, lilac alcohol B, lilac alcohol C, lilac alcohol D, α-pinene, sabinene, β-pinene, myrcene, d-limonene, eucalyptol, cis-ocimene, benzaldehyde, terpinolene, linalool, benzene acetaldehyde, α-terpineol, p-methoxyanisole, p-anisaldehyde, ( Z, E)-α-farnesene and ( E, E)-α-farnesene were the most abundant volatiles released from fresh flowers of S. oblata var. alba. The relative contents of main volatile fragrance were found to be different in emissions from two varieties of S. oblata flowers (white or purple in color). The four isomers of lilac alcohol and four isomer lilac aldehyde were the characteristic components of the scent of fresh flowers of S. oblata. The main volatile fragrance from fresh flowers of S. oblata var. alba in different florescence ((A) flower buds; (B) at the early stage of flower blooming; (C) during the flower blooming; (D) at the end of flower blooming; (E) senescence) were studied in this paper. The results demonstrated that headspace SPME–GC–MS is a simple, rapid and solvent-free method suitable for analysis of volatile compounds emitted from fresh flowers of S. oblata in different florescence.

Lilac alcohol epoxide: A linalool derivative in Actinidia arguta flowers

Lilac alcohol epoxide (2-(5-methyl-5-(oxiran-2-yl)-tetrahydrofuran-2-yl)propan-1-ol), a previously unreported monoterpene, was identified in the solvent extract of the flowers of seven Actinidia arguta genotypes. The diastereomeric lilac alcohol epoxides co-occurred with the lilac aldehydes and alcohols. Another compound, the lilac diol (2-(5-(1-hydroxyethyl)-5-methyl-tetrahydrofuran-2-yl)propan-1-ol) was synthesised as part of our efforts to identify the lilac alcohol epoxide.

Biogenetic studies in Syringa vulgaris L.: bioconversion of (18)O(2H)-labeled precursors into lilac aldehydes and lilac alcohols.

Syringa vulgaris L. inflorescences, petals, and chloroplasts, isolated from lilac flower petals, were fed with aqueous solutions of (18)O-labeled linalool and [5,5-(2)H(2)]-deoxy-d-xylose (DOX). The chloroplasts of lilac flower petals were isolated after feeding experiments with labeled precursors. Volatiles from the chloroplasts were extracted by stir bar sorptive extraction (SBSE) and analyzed using enantioselective multidimensional gas chromatography-mass spectrometry (enantio-MDGC-MS). Feeding experiments with DOX indicate that the novel mevalonate-independent 1-deoxy-d-xylose 5-phosphate/2C-methyl-d-erythritol 4-phosphate (DOX/MEP) is the decisive pathway of lilac aldehyde and lilac alcohol, respectively. Bioconversion of [(18)O]linalool into lilac aldehyde and lilac alcohol during in vivo feeding experiments was monitored, and the metabolic pathways are discussed.

Synthesis, structure elucidation, and olfactometric analysis of lilac aldehyde and lilac alcohol stereoisomers.

Structure elucidation of the lilac aldehyde and lilac alcohol stereoisomers was ascertained by (1)H nuclear magnetic resonance (NMR) spectroscopy, including intramolecular nuclear Overhauser effects of the separated diastereoisomers and anisotropic effects of the diastereomeric 2-phenylpropionyl ester, and (1)H, (1)H COSY NMR spectroscopy of synthesized (5'R)-configured stereoisomers, synthesized from (R)-linalool. Direct stereodifferentiation of the eight stereoisomers of lilac aldehyde and lilac alcohol, respectively, has been achieved, using enantioselective capillary GC. The elution order of the isomers was deduced from the chromatographic behavior of the (5'R)-configured diastereoisomers. Additionally, the odor thresholds of lilac aldehyde and lilac alcohol stereoisomers are reported.

Biogenetic studies in Syringa vulgaris L.: synthesis and bioconversion of deuterium-labeled precursors into lilac aldehydes and lilac alcohols.

Syringa vulgaris L. inflorescences were fed with aqueous solutions of regioselectively deuterated compounds assumed to be precursors of lilac aldehyde and lilac alcohol, respectively. Volatiles were extracted by stir bar sorptive extraction (SBSE) and analyzed using enantioselective multidimensional gas chromatography/mass spectrometry (enantio-MDGC/MS); deuterium-labeled lilac aldehydes and lilac alcohols were separated from unlabeled stereoisomers on a fused silica capillary column, coated with heptakis(2,3-di-O-methyl-6-O-tert-butyldimethylsilyl)-beta-cyclodextrin (DIME-beta-CD) (30%) in SE 52 (70%), as the chiral stationary phase. Feeding experiments with [5,5-(2)H(2)]mevalonic acid lactone 22 and [5,5-(2)H(2)]deoxy-d-xylose 23 indicate that the novel mevalonate independent 1-deoxy-d-xylose 5-phosphate/2C-methyl-d-erythritol 4-phosphate pathway is the dominant metabolic route for biosynthesis in lilac flowers. Additionally, bioconversion of deuterium-labeled d(5)-(R/S)-linalool 3, d(6)-(R)-linalool 21, d(5)-(R/S)-8-hydroxylinalool 6, d(5)-(R/S)-8-oxolinalool 7, d(5)-lilac aldehydes 8-11 and d(5)-lilac alcohols 12-15 into lilac during in vivo feeding experiments was investigated and the metabolic pathway is discussed. Incubation of petals with an aqueous solution of deuterated d(5)-(R/S)-linalool 3 indicates an autonomic terpene biosynthesis of lilac flavor compounds in the flower petals of lilac.

Intramolecular reactions of allyloxy radicals

Allyloxy radicals, formed by epoxide cleavage, have cyclised onto appropriately positioned alkenes to form tetrahydrofurans, and the diastereoselectivity of the cyclisation has been studied. The reaction was used to synthesise lilac alcohols which were then used to confirm the stereochemistry of such cyclisations.

Analysis of the floral fragrance of Platanthera stricta

The qualitative and quantitative composition of the floral fragrance of Platanthera stricta was determined by trapping fragrance components on charcoal or Tenax adsorbents in the field. Analysis (GC-MS) showed the fragrance to consist largely of lilac aldehydes, lilac alcohols and other monoterpene alcohols, monoterpene hydrocarbons (of which α-pinene is the predominant constituent), and aromatic aldehydes and alcohols. Rates of emission of fragrance among mature inflorescences varied greatly ( ca 50—0 μg/hr/inflorescence). Neither charcoal nor Tenax alone effectively trapped the full range of floral fragrance compounds. When Tenax was used as the trapping agent, lilac aldehydes, lilac alcohols, aromatic aldehydes, aromatic alcohols, and some of the monoterpenes were recovered, but α-pinene, a major component of the fragrance, was recovered only in trace amounts. By contrast, α-pinene and lilac alcohols were effectively recovered from charcoal, but aromatic aldehydes and alcohols were poorly recovered, and lilac aldehydes decomposed.

Photoreactivite de l'ester de dieckmann α-methyle. Applications de la reaction du type I de norrish a la synthese du dihydroterpenediol secrete par danaus chrysippus et a celle des alcools du lilas

The α-methyl Dieckmann ester, when irradiated with UV light, gives a mixture of relatively light stable E and Z isomers of 5-carbethoxyhex-4-en-1-al 2, (77% yield). Although the 2E isomer can be isolated in pure form in almost 50% yield, separation of the two isomers is unnecessary. Their formation has been used as a key step in the total synthesis of the dihydroterpenediol 3 (34% overall yield) secreted by Danaus Chrysippus (African Monarch), and the four lilac alcohols 4.

The Synthesis and the Absolute Configurations of Lilac Alcohols, New Naturally Occurring Odorous Ingredients of Lilac Flower

Abstract The conversion of racemic linalyl acetate to racemic lilac alcohols has been completed in 5 steps and four diastereoisomers of β,5-dimethyl-5-vinyl-2-tetrahydrofuranethanol were obtained. d-Lilac alcohols were also synthesized from d-linalyl acetate and confirmed to be identical with natural ones. The absolute configurations of lilac alcohol-a, -b, -c, and -d were respectively shown to be (βS, 2S, 5S), (βR, 2S, 5S), (βR, 2R, 5S), and (βS, 2R, 5S) by the chemical and physical evidences.

Terpenoids Part LXII: New Synthesis of 2,6-Dimethyl- 3,6-epoxyoct-7-enol(±)-Lilac alcohol

Terpenoids Part LXII: New Synthesis of 2,6-Dimethyl- 3,6-epoxyoct-7-enol(±)-Lilac alcohol

Terpenoids-Part LXII: New Synthesis of 2, 6-Dimethyl-3, 6-epoxyoct-7 -enol (±)-Lilac Alcohol

Terpenoids-Part LXII: New Synthesis of 2, 6-Dimethyl-3, 6-epoxyoct-7 -enol (±)-Lilac Alcohol

The Synthesis and Absolute Configurations of Lilac Alcohols

The Synthesis and Absolute Configurations of Lilac Alcohols