Synthesis of l,7-Diphenyl-l,3-heptadien-5-one,One of the Components in the Fresh Catkin of Alnus pendula

Several microorganisms capable of utilizing 1-aminocyclopropane-1-carboxylate (ACPC) were isolated from soil. A bacterium which belongs to Pseudomonas accumulated cellular α-aminobutyrate with consumption of ACPC and cells incubated with ACPC medium had the activity deaminating the substrate to form α-ketobutyrate. An enzyme, ACPC deaminase, was highly purified and its molecular weight, substrate specificity and absorption spectrum were investigated. These results suggested that this enzyme was a pyridoxal 5′-phosphate enzyme which has the molecular weight of 104000 and high specificity for ACPC, Km= 1.5 mM. A yeast, Hansenula saturnus, is also capable of forming ACPC deaminase, which has a lower molecular weight, 69000, and higher Km value, 2.6 mM.     

Synthesis of Prostaglandin-F1 Related Compounds

Synthesis of several prostaglandin-F₁ related compounds utilizing bicyclo(2,2,1) heptene derivatives as key intermediates were investigated.     

A Novel Synthetic Procedure for “Reverse” C-Nucleosides

The Colletotrichum lagenarium PKS1 gene was expressed in the heterologous fungal host, Aspergillus oryzae, under the starch-inducible α-amylase promoter to identify the direct product of polyketide synthase (PKS) encoded by the PKS1 gene. The main compound produced by an A. oryzae transformant was isolated and characterized to be 1,3,6,8-tetrahydroxynaphthalene (T4HN) as its tetraacetate. Since the PKS1 gene was cloned from C. lagenarium to complement the nonmelanizing albino mutant, T4HN was assumed to be an initial biosynthetic intermediate, and thus the product of the PKS reaction, but had not been isolated from the fungus. The production of T4HN by the PKS1 transformant unambiguously identified the gene to encode a PKS of pentaketide T4HN. In addition, tetraketide orsellinic acid and pentaketide isocoumarin were isolated, the latter being derived from a pentaketide monocyclic carboxylic acid, as by-products of the PKS1 PKS reaction. Production of the pentaketide carboxylic acid provided insights into the mechanism for the PKS1 polyketide synthase reaction to form T4HN.     

Biochemical Studies on “Bakanae” Fungus. Part 55 Synthesis of Gibberellins

In order to clarify the structure of ring A of gibberellins, thirteen lactones of cyclohexan series, of which eight were new, were prepared to examine their infrared spectra. So far; the experiment is concerned, γ-lactones show the characteristic absorption band in the rang 1775~1782 cm^?1 in dioxane, while 5-ones in the range 1730/~1762 cm^?1. Since the absorptio band due to lactone carbonyl of gibberellins occurs at the range 1777~1786 cm^?1 in dioxane, the lactone ring of gibberellins seems to be γ.     

The Synthetic Study of 2.3-Dihydro-lH-pyrrolo [1,2-a] indole Ring System

The 2,3-Dihydro-lH-pyrrolo[l,2-a]indole ring system was synthesised by the condensation reaction of toluquinone and 2-cyanomethylenepyrrolidine.     

Syntheses and Configurational Analysis of Rotenoids,XIX The Total Synthesis of Natural Rotenone

d,l-Derrisic acid (IIa, R′: H) was synthesized from d,l-hydroxy dihydrotubanol (Ve) by Hoesch condensation with a nitrile (VI). The possible optical resolution of d,l-IIa was demonstrated by a conventional “reversed resolution” method.

This communication and previous works constitute the first total synthesis of natural rotenone (Ia).     

Structure and Synthesis of a Minor Component in the Oxidation Products of Crude Natural Variotin Oxidized with Manganese Dioxide,and Its Reduction with Lithium Aluminum Tri-t-butoxy Hydride

The structure of a minor component in the oxidation products of crude natural variotin oxidized with manganese dioxide is elucidated. The synthesis of the investigated compound, N-(6-oxo-2,4-trans, tralls-heptadienoyl) 2-pyrrolidonide, and the reduction of the substance are also described.     

A Stereoselective Synthesis of Antimycinone A3 and Its Stereoisomers

Antimycinone A₃, which is a neutral fragment of mild alkaline hydrolysate of antimycin A₃, and its stereoisomers were synthesized stereoselectively from methyl trans-2-n-butylpent-3-enoate or methyl cis-2-n-butylpent-3-enoate, and natural antimycinone A₃ was proved to possess Hα-Hβ and Hβ-Hγ trans configuration.     

Chemical Studies on Ambergris

So called ambreinolal (IV),* a component of ambergris, was first synthesized by CrO₃ oxidation of ambreinolol (III)* which was obtained from ambreinolide (II) by reduction with LiAlH₄. Ambreinolol (III) was converted to the C₁₇-saturated oxide (VII) in a good yield through the monotosylate (VIII) by treatment with p-toluenesulfonyl chloride in pyridine.

Ambrein (I), a major constituent of ambergris, was easily converted to ambrein-tetrahydropyranylether (II), of which thermal decomposition gave back ambrein (I). The tetrahydropyranylether (II) was oxidized to ambreinolal-tetrahydropyranylether (V) in two steps. Ambreinolal-tetrahydropyranylether (V) was synthesized from ambreinolol (VII) in four steps and converted to the C₁₇-unsaturated oxide (VI) on heating.