Ivan V. Peterson

Cell growth and accumulation of polyhydroxyalkanoates from CO2 and H2 of a hydrogen-oxidizing bacterium, Cupriavidus eutrophus B-10646.

Synthesis of polyhydroxyalkanoates (PHAs) by a new strain of Cupriavidus - Cupriavidus eutrophus B-10646 - was investigated under autotrophic growth conditions. Under chemostat, at the specific flow rate D=0.1h(-1), on sole carbon substrate (CO2), with nitrogen, sulfur, phosphorus, potassium, and manganese used as growth limiting elements, the highest poly(3-hydroxybutyrate) [P(3HB)] yields were obtained under nitrogen deficiency. In batch autotrophic culture, in the fermenter with oxygen mass transfer coefficient 0.460 h(-1), P(3HB) yields reached 85% of dry cell weight (DCW) and DCW reached 50 g/l. Concentrations of supplementary PHA precursor substrates (valerate, hexanoate, γ-butyrolactone) and culture conditions were varied to produce, for the first time under autotrophic growth conditions, PHA ter- and tetra-polymers with widely varying major fractions of 3-hydroxybutyrate, 4-hydroxybutyrate, 3-hydroxyvalerate, and 3-hydroxyhexanoate monomer units. Investigation of the high-purity PHA specimens showed significant differences in their physicochemical and physicomechanical properties.

Physicochemical properties of multicomponent polyhydroxyalkanoates: Novel aspects

The physicochemical properties such as the degree of crystallinity and temperature and molecularmass characteristics of a number of polyhydroxyalkanoates of various chemical composition synthesized on a complex carbon substrate by bacteria Cupriavidus eutrophus В10646 have been investigated. Two-, three-, and four-component copolymer samples have different sets and ratios of monomers with various lengths of carbon chains: 3-hydroxybutyrate (3HB), 4-hydroxybutyrate (4HB), 3-hydroxyvalerate (3HV), 3-hydroxyhexanoate (3HH), 3-hydroxy-4-methyl valerate (3H4MV), and diethylene glycol (DEG). It has been shown that weight-average molar mass М w and polydispersity vary in a wide range with no correlation existing with the composition of copolymer polyhydroxyalkanoates and that thermal stability is preserved in the temperature interval between the melting temperature and the thermal degradation temperature from 100 to 120–140°С. The composition and ratio of monomers most notably affect the degree of crystallinity of polyhydroxyalkanoates. Significant differences between the degrees of crystallinity of three- and four-component polyhydroxyalkanoates have been found for the first time. The degree of crystallinity for copolymers P(3HB/3HV/4HB) is 9–22%, and the degree of crystallinity for copolymers P(3HB/3HV/3HH) and P(3HB/3GV/3H4MV) is 41–63%; this value is close to the degree of crystallinity for diblock copolymers P(3HB)/DEG, which is 56–69%. For the four-component copolymers P(3HB/3GV/4HB/3HH), the degree of crystallinity is 30–41%. The values of М w for the copolymers P(3HB/DEG) are inhomogeneous and the polymers contain fractions uneven with respect to molecular mass: a high-molecular-mass polymer (М w from 2700 to 4900 kDa) and a low-molecular-mass polymer (М w = 46–167 kDa). For the copolymers P(3HB)/DEG and P(3HB/3HV/3H4MV), two peaks are observed in the region of melting with the gap between these peaks being 4–20°С. All of the types of copolymer samples, regardless of the monomer ratio, show an increase in elongation at break against the background of a decrease in tensile stress and Young’s modulus, with these effects being pronounced to different extents. On the whole, the properties of multicomponent polyhydroxyalkanoates differ appreciably.

Preparation of adamantyl derivatives of 1,4-; 1,6- and 1,7-dihydroxynaphthalenes and assignment of their NMR data

Adamantylation of dihydroxynaphthalenes with the hydroxyl groups on the same or different rings leads to compounds that are convenient starting materials in target‐oriented organic synthesis. Here, we report the 1H and 13C NMR assignments of eight 1‐adamantyl substituted derivatives of 1,4‐; 1,6‐ and 1,7‐dihydroxynaphthalenes. The data acquired and peculiarities of their molecular structure are useful for extrapolation for prompt characterization of compounds containing adamantane, dihydroxynaphthalenes or naphthoquinone units. Copyright

Adamantylation of polysubstituted arenes in trifluoroacetic acid

A reaction of 2,3-xylenol, 2,3-dichlorophenol, and 1,3-disubstituted benzenes with 1-adamantanol in trifluoroacetic acid leads to the corresponding monoand diadamantylated products.

Spectral assignment of new adamantane derivatives of 1,3-; 1,5-dihydroxy- and 1,5-dimethylnaphthalenes

1,3(I) and 1,5-dihydroxynaphthalens (II) as well as 1,5dimethylnaphthalene (III) are considered and investigated as template for building up various derivatives due to specific arrangement of the hydroxyl groups in its molecule (orthoandmetafor I; orthoand perifor II-III). Furthermore, some compounds containing resorcinol moiety exhibit depigmentation activity. A wide applications of adamantane derivatives allows to suggest that containing in its structure above-listed compounds I-III are of definite practical interest. Also it should be noted that aromatic compounds with an adamantane at the ortho-position to the hydroxyl groups are the key skeletons of synthetic retinoid analogues and supporting ligands of many homogeneous transition-metal catalysts. Moreover, recently much attention has been heeded to dearomatization reactions of aromatic and heteroaromatic compounds due to the highly reactive intermediates opportunities. Current report is an ongoing research of determination structure and features of adamantyl derivatives of dihydroxynaphthalenes by NMR spectroscopy. We describe here assignments of H and C NMR spectra of synthesized 1-adamantyl substituted compounds I-III. Additionally, previously defined patterns on the effect of OH-group in the orthoormetaposition to adamantane for its H and C NMR spectra have been confirmed on the basis of found spectral data. Such information can be useful for unambiguous interpretation of more sophisticated adamantyl derivatives of various naphthalene-units contain compounds, including their dearomatized derivatives.

1H and 13C NMR spectral assignments of novel adamantyl and di-adamantyl derivatives of 1,2-dihydroxynaphthalenes, 1,8-dihydroxynaphthalenes, 2,3-dihydroxynaphthalenes, 2,6-dihydroxynaphthalenes and 2,7-dihydroxynaphthalenes

Despite the fact that since the discovery and development methods of preparation and isolation of various dihydroxynaphthalenes passed a long time, at present, each of the ten isomers continue to find more and more fields of application. Among them, 1,8-dihydroxynaphthalene and their derivatives take a special place because the peri-interactions in 1,8-substituted naphthalene skeleton have an influence on the physical and chemical properties of these compounds. In addition, currently, the properties of equatorenes [chiral polycyclic aromatic hydrocarbons containing bis(1-adamantyl) groups at the peri-positions] were actively investigated, and in the case of 1,8-bis(1-adamantyl)naphthalene, a distortion of an aromatic ring system was determined. Studies by NMR spectroscopy of various perieffects of naphthalene-containing compounds as well as analysis of influence of different-sized substituents on an aromaticity in hydroxynaphthalene system are an important topic in NMR literature. On the other hand, to date, numerous studies have reliably found that the adamantyl moiety generally increases the lipophilicity and positively modulates the therapeutic index of many experimental substances via various mechanisms. Many of these adamantylmodified compounds contain in their structure a variety of aromatic components. Beyond pharmaceutical chemistry, the most practical applications are discovered among hydroxyaromatic compounds with adamantane in the ortho-position relative to the hydroxyl groups. In addition, nuclear magnetic resonance properties of adamantane, its derivatives, and higher adamantalog series continue to be actively explored. We continue to describe adamantyl derivatives of the homologous series of different naphthalenediols and their NMR features. Previously, NMR spectra of 1,4-dihydroxynaphthalenes, 1,6-dihydroxynaphthalenes, 1,7-dihydroxynaphthalenes, 1,3dihydroxynaphthalenes and 1,5-dihydroxynaphthalenes with one or two adamantyl groups were characterized in details. In the current paper, we report complete H and C spectral assignments of mono-adamantyl and di-adamantyl-containing derivatives of 1,2-dihydroxynaphthalenes, 2,3-dihydroxynaphthalenes, 2,6-dihydroxynaphthalenes, 2,7-dihydroxynaphthalenes and 1,8-dihydroxynaphthalenes and 6-(1-adamantyl)-2,3-dihydroxynaphthalene synthesized previously. Some of these NMR spectra show expected features associated with the symmetry of the molecules. The obtained results, together with the data from previous articles, will expand information on the effect of bulky substituents on molecular constitution of hydroxynaphthalene systems and thus will be a useful resource in their structure elucidation by NMR spectroscopy.

Improved Synthesis of 2-(1-Adamantyl)-4-bromophenol and 2-(1-Adamantyl)-4-bromoanisole, Intermediates in Adapalene Synthesis

A new simple and environmentally friendly synthetic method for 2-(1-adamantyl)-4-bromophenol that did not use catalysts and solvents was developed. A new simplified preparation method for 2-(1-adamantyl)-4-bromoanisole in one step instead of two was proposed. Both compounds are intermediates in the first and second synthetic steps to 6-[3-(1-adamantyl)-4-methoxyphenyl]-2-naphthoic acid (adapalene).