Three nepetalactones were isolated from Nepeta racemosa (mussinii) by traditional methods. An improved method was developed to isolate nepetalactones from N. faassénii. An epimerization procedure was used to prepare the fourth 7S-nepetalactone diastereomer. The cis-fused nepetalactols were prepared by reduction of the corresponding nepetalactones, while the trans-fused nepetalactols were unstable and found to undergo ring-opening reactions yielding iridodials. The characterizations and structural assignments by means of NMR agree with quantum chemical density functional calculations.

trans-Sabinene hydrate (1), was synthesized from (−)-3-thujol (2) in four steps. The key step was the selective formation of trans-2-hydroxy-3-thujene (6) by photooxygenation of a 3:1 mixture of 2- and 3-thujenes (4 and 5) obtained from (−)-3-thujol mesylate (3). Hydrogenation of 6 gave compound 1 in 46% overall yield.

The extract (IPA) of leaves from Ipomoea pes-caprae (L.) R. Br. has previously been shown to reduce the development of rat ear oedema induced by ethyl phenylpropiolate (EPP) in a dose-dependent manner. Using this bioassay to guide fractionation of the extract, two diastereomeric compounds, the actinidols 1a and 1b, were isolated (0.8% of IPA). The actinidols constitute part of the active principle of IPA. Compounds, previously isolated from IPA, with either prostaglandin synthesis inhibiting activity in vitro [2-hydroxy-4,4,7-trimethyl-1(4H)-naphthalenone, (-)-mellein and eugenol] or antispasmodic activity (E-phytol) were also assayed for inhibitory effects on the development of EPP-induced rat ear oedema. They all reduced oedema formation dose-dependently. The results suggest that IPA consists of several active compounds which interfere with the process of inflammation in different ways.

The crude extract (IPA) of the plant Ipomoea pes-caprae (L.) R. Br. has previously been shown to antagonize smooth muscle contractions induced by several agonists via a non-specific mechanism. Bioassay-guided fractionation of IPA resulted in isolation of the antispasmodically acting isoprenoids beta-damascenone and E-phytol. Their antispasmodic potencies were found to be in the same range as that of papaverine, a general spasmolytic agent. This effect was suggested to play a role in the previously observed anti-inflammatory activity of IPA by interfering with the contraction of endothelial cells. Severe vascular contraction has been shown to be involved in the dermatitis caused by toxic jellyfishes. It is possible that beta-damascenone and E-phytol, by interfering with the contraction of vascular smooth muscle cells, are partly responsible for the previously reported effectiveness of IPA in the treatment of such dermatitis.

The crude extract (IPA) of the plant Ipomoea pes-caprae (L.) R. Br. has previously been shown to antagonize smooth muscle contractions induced by several agonists via a non-specific mechanism. Bioassay-guided fractionation of IPA resulted in isolation of the antispasmodically acting isoprenoids beta-damascenone and E-phytol. Their antispasmodic potencies were found to be in the same range as that of papaverine, a general spasmolytic agent. This effect was suggested to play a role in the previously observed anti-inflammatory activity of IPA by interfering with the contraction of endothelial cells. Severe vascular contraction has been shown to be involved in the dermatitis caused by toxic jellyfishes. It is possible that beta-damascenone and E-phytol, by interfering with the contraction of vascular smooth muscle cells, are partly responsible for the previously reported effectiveness of IPA in the treatment of such dermatitis.

All-trans acyclic isoprenoid skeletons were made through a two-step iterative sequence. The method involves the Claisen rearrangement of allyl vinyl ethers formed from allylic alcohols and the dimethyl acetal of methyl isopropenyl ketone, followed by LiAlH4 reduction of the α,β-unsaturated ketone formed by rearrangement. The α,β-unsaturated ketone was also transformed to the 2-methyl-1-propenyl group by using a one-pot deoxygenation reaction for the synthesis of (E)-β-farnesene, (E)-β-springene and dendrolasin.

The crude extract (IPA) of the plant Ipomoea pes-caprae (L.) R. Br. showed a inhibitory effect of prostaglandin synthesis in vitro. Bioassay-guided separation of the extract led to the isolation of four active compounds: 2-hydroxy-4,4,7-trimethyl-1(4H)-naphthalenone (1), (-)-mellein (2), eugenol (3), and 4-vinyl-guaiacol (4). Among the isolated compounds, 3 and 4 were the most active with IC50 values of 9.2 and 18-mu-M, respectively. For 1 and 2 the IC50 values were 230 and 340-mu-M, respectively. The influence of 1, 2, 3, and 4 on the formation of prostaglandins may partly explain a previously observed anti-inflammatory effect of the extract IPA.

Claisen rearrangements of allyl vinyl ethers, formed in situ by the acid catalyzed reaction of dimethyl acetals of acetaldehyde, acetone and isopropeny] methyl ketone with different types of allylic alcohols, have been compared. The primary, secondary and tertiary allylic alcohols used in the investigation were selected to serve as models for isoprenoid synthesis. The basis for two feasible methods that can be iterated to create isoprenoid chains has been investigated.

Synthesis of racemic lineatin (1), a pheromone component of Trypodendron lineatum, is described. Condensation of 5-methyl-5-hexen-2-one (2) and triethyl phosphonoacetate with LiN(SiMe3)2 gave esters 3, which upon hydrolysis gave acids 4a-f. The bicyclo[3.2.0] ring compounds 5 and 6 were obtained via an intramolecular [2 + 2] addition by refluxing underivatized carboxylic acids 4a-f with NaOAc and Ac2O. Compound 5 was isomerized to the thermodynamically more stable isomer 6 using a Pd/C catalyst activated with hydrogen. Reduction of 6 with LiAlH4 gave the endo and exo isomers 7a and 7b (4:1). Isolation of the alcohol 7a followed by acetylation gave 8. Subsequent oxidation with OsO4 and methylmorpholine N-oxide gave diol 9. Cleavage of 9 with H5IO6 in diethyl ether gave keto aldehyde 10, which was converted to keto acetal 11. Treatment of 11 with MeMgBr followed by acidic workup gave 1. The overall efficiency is approximately 20%.

A simple synthesis of trans-β-farnesene, an alarm pheromone for aphids, from myrcene is described and a reliable procedure for working up of DIBAH reduction from esters to aldhydes is introduced.

AbstractIsopropenyl methyl ketone (I) is coupled with methacrolein (II) to generate the hydroxy dienone (III).

Ipomoea pes-caprae (L.) R. Br. (Convolvulaceae) is a plant that grows on sandy seashores in tropical climate, and has been reported to be used in traditional medicine for various disorders including inflammation (1). In Thailand the leaves of this plant are also used to treat skin injuries caused by poisonous jelly fish. We have previously reported on the antagonistic activity of the plant extract, obtained from petroleum ether extraction of a water distillate of the leaves (IPA, 0.05% yield), toward jelly fish poison as well as different agonists on isolated guinea pig ileal smooth muscle (2, 3). In a clinical study, IPA decreased the symptoms of dermatitis caused by jelly fish sting (4). In our continuing study aimed at relating the traditional use of this plant to the active compounds present, we have investigated the anti-inflammatory properties of IPA both in vivoand in vitro.

A simple synthesis of some furanomonoterpenes, including natural perillene, was realized on the basis of the cyclopropylcarbinyl homoallylic rearrangement.

Methyl (2E,4Z)-2,4-decadienoate (1), an important pheromone component of Pityogenes chalcographus, and its three geometrical isomers (2–4) have been synthesized and obtained in 99 % isomeric purity. Urea inclusion complexes were used in the final purification procedures. Spectroscopic data (MS, 1H and 13C NMR) of all four isomers are discussed. A photoisomerization study of the decadienoates is presented.

AbstractMannich reaction of the propynol (I) yields the amine (IV), which is converted to the precursor (VII).

In field experiments in Sweden, the constituent 2-methyl-3-buten-2-ol of the aggregation pheromone of the spruce bark bettleIps typographus (L.) was effectively replaced by 2-methyl-3-butyn-2-ol.

AbstractBei der Photolyse von Thymol (I) entstehen neben dem gewünschten Umbellulon (II) die Ketone (III) und (IV) sowie die Phenole (V).

The specificity of receptor cells specialized for the bark beetle pheromone component, ipsdienol, was studied electrophysiologically (extracellular recordings) in species ofIps. Single cells were tested with both ipsdienol enantiomers, their racemate, and racemates of structurally similar compounds. The two cell types, keyed to (+)- and to (−)-ipsdienol, respectively, showed much weaker responses to the analogues, demonstrating the high specialization of the cells. The relationships between the dose-response curves of the two types were similar, favoring the concept of particular membrane receptor types (acceptors) in both cell types.