Enzymatic resolution and odor description of both enantiomers of lavandulol, a fragrance of lavender oil.

Both enantiomers of lavandulol (1), an important constituent of lavender oil, were prepared by enzymatic optical resolution, and the odor quality of the single antipodes were evaluated. The fragrance of the nature-identical (R)-enantiomer ('weak floral, herbal odor with slightly lemon-like, fresh citrus fruity nuance') was superior to those of both the unnatural (S)-enantiomer ('very weak odor') and the racemate ('weak floral, herbal odor').

Intramolecular migration of long chain acyl group of enacyloxin IIa methyl ester.

Enacyloxin IIa methyl ester in non-protic solvent gave rearranged product in acidic conditions such as surface of TLC plate of silica gel or by treatment with a catalytic amount of p-toluenesulfonic acid. On the other hand, such a rearrangement did not occur in polar protic solvent. The structure of the rearranged product was elucidated as 4-acyl analog of the cyclohexane ring.

Total synthesis of cis-solamin.

[structure: see text] A convergent total synthesis of cis-solamin and its diastereomer was accomplished using VO(acac)2-catalyzed diastereoselective epoxidation followed by cyclization of bis-homoallylic alcohol as the key step. By comparison of the optical rotation of two possible diastereomers, it is suggested that the absolute configuration of natural cis-solamin is 1a.

Incorporation of Farnesyl Pyrophosphate Derivertives into Abscisic Acid and Its Biosynthetic Intermediates in Cevcospova cruenta.

To investigate the transformation from (2E,6E)-farnesyl pyrophosphate to (2Z,4E)-γ-ionylideneethanol in the abscisic acid-producing fungi, Cercospora cruenta, plausible [2-14C]-C15 intermediates were prepared and fed. Substrates such as (2E,6E)-farnesyl pyrophosphate, (2Z,4E)-γ-ionylideneethanol and its pyrophosphate were incorporated into ABA and its known biosynthetic precursors. It is suggested that (2E,6E>farnesyl pyrophosphate is converted to (2Z,4E)-γ-ionylideneethanol in four consecutive steps: dehydrogenation, isomerization, cyclization and hydrolysis.

Biosynthesis and metabolism of abscisic acid and related compounds.

This review describes research on the chemistry (biosynthesis, metabolism and synthetic analogs) of a plant hormone, abscisic acid (ABA), covering 1970 to 2002 with 123 references

Preparation of N-substituted aryl and alkyl carbamates and their inhibitory effect on oat seed germination.

A series of N-substituted aryl and alkyl carbamates (RNHCOOR'; R: aryl, alkyl; R': aryl, alkyl) was prepared and screened for inhibitory activity toward the germination of oat seeds. The activity of each compound was compared with that of chlorpropham (isopropyl 3-chlorocarbanilate). Some of the synthetic carbamates possessing the N-(phenylthio)methyl group, PhSCH2NHCOOR', showed inhibitory activity close or comparable to that of chlorpropham.

Polyoxygenated cyclohexenes from the Chinese tree, Uvaria purpurea.

Four new polyoxygenated cyclohexenes, 2-O-acetyl-6-O-methylzeylenol (2), 2-O-benzoyl-3-O-debenzoylzeylenone (5), 3-O-debenzoylzeylenone (6) and 3-O-debenzoylgrandiflorone (8), were isolated from the leaves of Uvaria purpurea. 2-O-acetyl-6-O-benzoylzeylenol (3) was also isolated for the first time as a natural product. Compounds 5-7 each showed inhibitory activity against the root growth of Lactuca sativa. Their structures were established by spectroscopic and chemical methods.

A new drimane from the heartwood of the Japanese yew, Taxus cuspidata.

A new drimane sesquiterpenoid was isolated from the heartwood of the Japanese yew, Taxus cuspidata Sieb. et Zucc. Its structure was established as 1beta-acetoxyisodrimeninol (1beta-acetoxy-11,12-epoxy-7-drimen-11-ol, 1). This compound was gradually oxidized to give y-lactone (1beta-acetoxy-8-drimeno-11,12-lactone, 4).

Synthesis and biological evaluation of 4-deacetoxy-1,7-dideoxy azetidine paclitaxel analogues.

Three novel 4-deacetoxy-1,7-dideoxy azetidine paclitaxel analogues were synthesized through a convenient route that employed hydroboration-amination and intramolecular S(N)2-type substitution reaction from a natural taxoid taxinine. All analogues have been tested for cytotoxicity against three human tumor cell lines. None of them showed remarkable cytotoxicity compared to paclitaxel against tested tumor cell lines.

New 2(3-->20)abeotaxane and 3,11-cyclotaxane from needles of Taxus cuspidata.

Two new taxoid metabolites, 2alpha,7beta,10beta-triacetoxy-5alpha,13alpha-dihydroxy-2(3-->20)abeotaxa-4(20),11-dien-9-one (1) and 2alpha-acetoxy-5alpha-cinnamoyloxy-9alpha,10beta-dihydroxy-3,11-cyclotax-4(20)-en-13-one (2), were isolated from the methanol extract of needles of the Japanese yew, Taxus cuspidata.