Syntheses of Terpenes by the Condensation of Aliphatic Compounds

Treatment of mesityloxide with basic condensing agents resulted in formation of isoxylitones-A, B, C and D and isophorone. These compounds were purely isolated and assigned their structures from spectroscopic and chemical evidences. Isoxylitone-A and isoxylitone-B were conformers of 1-acetyl-2, 4, 6, 6-tetramethyl-1, 3-cyclohexadiene separated by the rotational barrier of acetyl group and interconversional barrier of cyclohexadiene ring. Isoxylitone-C was 4-isopropenyl-1, 5, 5-trimethyl-1-cyclohexen-3-one. Isoxylitone-D was 5, 5-dimethyl-3-(1-isobutenyl)-2-cyclohexen-1-one.     

Syntheses of Terpenes by the Condensation of Aliphatic Compounds

The condensation of mesityloxide with 4-diethylaminobutanone-(2) in the presence of potassium t-butoxide gave the products containing piperitenone together with isoxylitones, which were identified by gas chromatography and chemical methods. The effects of the combination of condensing agent, solvent, molar ratio of reagents and reaction temperature on the components in the condensation products were studied. It was found that piperitenone was able to obtain in an yield of 51% on the basis of 4-diethylaminobutanone-(2) by the use of Triton-B as a condensing agent. Also piperitenone can be isolated from the condensation products by the treatment with semicarbazide.     

Volatile Compounds Produced by the Reaction of L-Cysteine or L-Cystine with Carbonyl Compounds

Sulfur-containing amino acids (L-cysteine or L-cystine) were reacted with D-glucose or pyruvaldehyde at various temperatures and submitted to flavor evaluation. The nuance of the aroma was changed with temperature, and the most acceptable aroma (Japanese rice cracker with sesame-like) was produced at 160°C in all the samples. Volatile compounds produced at 160°C were investigated by gas chromatography and GC–MS coupling. Many compounds such as thiazoles and thiophenes found in the volatiles of some foodstuffs were identified.     

Carbonyl Compounds Produced by Cryptomonas ovata var. palustris*

SYNOPSIS. Some neutral carbonyl compounds synthesized by Cryptomonas, ovata var. palustris were identified as methanal, ethanal, 2-propanone, pentanal, and heptanal by means of thin-layer chromatography, gas chromatography and infrared spectroscopy.     

Syntheses of Compounds Possessing Chicken-Flavor

2,4-Decadien-1-ol and 2,4-dodecadien-1-ol were synthesized from n-caproaldehyde and caprylaldehyde, respectively and their flavors were shown to be similar to those of chicken meat and chicken fat.     

Synthesis of Aromatic Carbonyl Compounds by Friedel-Crafts Reaction Using BF3 Catalyst

Friedel-Crafts reaction using BF₃ catalyst was investigated in order to synthesize various carbonyl compounds.     

Reactivities of Some Carbonyl Compounds in Strecker Degradation

The amount of isovaleraldehyde produced by the reaction of l-leucine with various carbonyl compounds including degradation products of sugar was determined, and relative reactivities of these carbonyl compounds in Strecker degradation were compared. The relatively high reactivity of dl-glyceraldehyde in Strecker degradation was considered to be partly due to the formation of pyruvaldehyde which was isolated as its bis-2, 4-dinitrophenyl-hydrazone from the reaction mixture of l-leucine and dl-glyceraldehyde. Formation mechanism of pyruvaldehyde was also proposed.     

Syntheses of Thiadiazolopyrimidine and Related Compounds

A homologous transformation system was developed using the endogenous ATP-sulfurylase gene, AasC, as a selectable marker in Aspergillus aculeatus. Spontaneous mutation was proved to be beneficial in isolating AasC-deficient mutants. Molecular analysis of sC ⁺ transformants revealed that the frequency of single copy integration at ATP-sulfurylase locus was more than 40%.     

Spot Test of Some Carbonyl Compounds Using Their Fluorigenic Reactions with o-Aminodiphenyl

A new spot test on silica gel thin-layers of some carbonyl compounds was described, which was based on their fluorigenic reactions with o-aminodiphenyl dissolved in diluted sulfuric acid. Pyridoxal, higher fatty aldehydes, glycolaldehyde, glyoxylic acid and 2,3-pentanedione gave brilliantly fluorescent spots in UV light by heating with the reagent sprayed. Some other non- or sparingly volatile carbonyls also gave positive results.

The reaction of glyoxal with the reagent was carried out in aqueous solution. A linear relationship between the fluorescence intensity and glyoxal concentration was observed.     

The Synthesis of Cyclotene and Its Related Compounds by the Acyloin Condensation

A mutant which required glutamate for growth as the sole nitrogen source was derived from alkalophilic Bacillus No. 8–1 by UV irradiation. The relationship was examined between cell growth and glutamate transport into cells.

Cell growth and glutamate transport into cells were dependent on extracellular pH in the presence of Na⁺, and both were maximum between pH 9 and 10. The quantitative relation between specific growth rate and glutamate uptake rate indicated that the amount of glutamate required for growth at pH 7 and 9 was consistent with that of glutamate transported at pH 7 and 9, respectively. But the amount of glutamate transported at pH 7 was not sufficient to support growth at pH 9. The glutamate transport system of this mutant strain evidently had an effect on growth.     

Anti-Prelog Reduction of Prochiral Carbonyl Compounds by Oenococcus oeni in a Biphasic System

An aqueous-organic biphasic system was established and used with whole cells of Oenococcus oeni to reduce 2-octanone to (R)-2-octanol. The conversion reached 99% when the Tris/borate buffer was increased from 50 mM to 300 mM in the aqueous phase. In addition, the conversion increased as the log P value of the organic solvent changed from 0.5 to 6.6. Under optimized conditions, the conversion of (R)-2-octanol reached 99% from 0.5 M 2-octanone with an optical purity of 99% e.e. The biphasic system allows the anti-Prelog reduction of aliphatic and aromatic ketones to furnish (R)-configurated alcohols in high optical purity as well.     

Facile Syntheses of C-Glycosides of Aromatic Compounds

Aspartokinase (ATP: l-aspartate 4-phosphotransferase) was extracted and partially purified 11-fold from an extreme thermophile, Thermus flavus AT–62. The enzyme has a temperature optimum near 75°C and a pH optimum of 7 to 8. The enzyme activity was feedback inhibited 80% by l-threonine at the concentration of 0.1 mm at 60°C. No concerted effect of l-threonine with any other aspartate family amino acids was observed. The aspartokinase and homoserine dehydrogenase activities were eluted at different concentrations of KCl from DEAE-cellulose column. The aspartokinase was not inactivated after 30 min at 70°C, but 30% of the original activity was lost after 30 min at 80°C and rapid inactivation occurred above 85°C. The allosteric sensitivity of the enzyirie was maintained even at 60~80°C but was reduced with the increase of temperature, accompanying desensitization above 80°C. The heat stability of the enzyme activity and of the allosteric sensitivity was discussed in comparison with other allosteric enzymes of thermophiles.     

Syntheses of Paromamine and Its Related Compounds

Paromamine and its related compounds were synthesized by a modified Königs-Knorr reaction of 3,4,6-tri-O-acetyl-2-(2′,4′-dinitroanilno)-α-d-glucopyranosyl bromide with isopropylidene derivatives of 2-deoxystreptamine, streptamine and dihydroconduramine F–4. The condensed products were isolated as their poly N-acetyl derivatives and proved to have α-configuration by PMR spectroscopy in D₂O.     

NADH Model Reaction: Asymmetric Reduction of Non-activated Carbonyl Compounds with N-Anionized Hantzsch Ester

As model compounds for NADH coenzymes, three chiral Hantzsch ester-type dihydro-pyridines were prepared. By their use and 2,6-dimethyl-3,5-dicarbo-( — )-menthoxy-1,4-dihydropyridine that had already been prepared, asymmetric reductions of unactivated prochiral ketones were conducted under the action of alkali metal derivatives at room temperature in a non-polar solvent, and the alcohol product were obtained in a 36~80% chemical yield and 30~60% enantiomeric excess.     

Syntheses of Naturally Occurring Terphenyls and Related Compounds

Naturally occurring terphenyls and related compounds such as terferol and its corresponding quinone and phlebiarubrone were synthesized from 2,5-diphenyl-1,4-benzoquinone. According to the proposed biosynthetic pathway, chemical conversion of phlebiarubrone to ustalic acid, a toxic compound isolated from the poisonous mushroom, Tricholoma ustale, was examined to find a low-yield conversion to the ustalic acid dimethyl ester.