Synthesis of a Prostaglandin Intermediate and Synthesis of Dihydrojasmone and Methyl Dihydrojasmonate

The synthesis of 2-(6-methoxycarbonylhexyl)cyclopent-2-ene-1-one (5), a valuable intermediate in the synthesis of prostaglandins, is described starting from ethyl 3-oxoglutarate (1). The same reaction sequence also produces dihydrojasmone (12) and methyl dihydrojasmonate (13).     

Synthesis and study of phosphoenolthiopyruvate

Phosphoenolthiopyruvate, the analogue of phosphoenolpyruvate in which the bridging oxygen of the phosphate ester is replaced by sulfur, has been synthesized from methyl acrylate and dimethyl (chlorothio)phosphonate. The compound is a substrate for alkaline phosphatase, pyruvate kinase, enolase, and phosphoenolpyruvate carboxylase. Both pyruvate kinase and phosphoenolpyruvate carboxylase convert the compound to thiopyruvate, which is a substrate for lactate dehydrogenase. Phosphoenolpyruvate carboxylase is slowly inactivated by phosphoenolthiopyruvate.     

Synthesis and evaluation of alpha-LNA

Three different synthetic routes to the alpha-configured LNA thymine monomer starting from D-allose or D-arabinose were investigated. The introduction of one or four alpha-LNA monomers into alpha-DNA had a destabilizing effect on the duplexes. However, a fully modified alpha-LNA sequence displayed strong recognition of complementary RNA, but no transition with DNA.     

Synthesis and secretion of GnRH

Comprehensive studies have provided a clear understanding of the effects of gonadal steroids on the secretion of gonadotropin releasing hormone (GnRH), but some inconsistent results exist with regard to effects on synthesis. It is clear that regulation of both synthesis and the secretion of GnRH are effected by neurotransmitter systems in the brain. Thus, steroid regulation of GnRH synthesis and secretion can be direct, but the predominant effects are transmitted through steroid-responsive neuronal systems in various parts of the brain. There is also emerging evidence of direct effects on GnRH cells. Overriding effects on synthesis and secretion of GnRH can be observed during aging, in undernutrition and under stressful situations; these involve various neuronal systems, which may have serial or parallel effects on GnRH cells. The effect of aging is accompanied by changes in GnRH synthesis, but comprehensive studies of synthesis during undernutrition and stress are less well documented. Altered GnRH and gonadotropin secretion that occurs in seasonal breeding animals and during the pubertal transition is not generally accompanied by changes in GnRH synthesis. Secretion of GnRH from the brain is a reflection of the inherent function of GnRH cells and the inputs that integrate all of the central regulatory elements. Ultimately, the pattern of secretion dictates the reproductive status of the organism. In order to fully understand the central mechanisms that control reproduction, more extensive studies are required on the neuronal circuitry that provides input to GnRH cells.     

Relationship Between Protein Synthesis and Viral Deoxyribonucleic Acid Synthesis

Evidence is presented that poxvirus deoxyribonucleic acid (DNA) synthesis required concurrent protein synthesis. The protein requirement in question can be distinguished from viral-induced thymidine kinase and DNA polymerase by virture of the instability of its messenger ribonucleic acid and its stoichiometric rather than catalytic relation to DNA synthesis. The protein(s) required did accumulate in the presence of fluorodeoxyuridine, an inhibitor of DNA synthesis, and, thus, appeared to be an "early" poxvirus function. The protein(s) was stable since it did function several hours after its synthesis had been terminated by puromycin. Two possible roles for such a protein requirement are discussed.     

Synthesis and characterisation of polyglucuronan

Several samples of polyglucuronan have been prepared by oxidation of cellulose with nitrogen oxides. Optimisation of the reaction conditions in terms of degree of oxidation and molecular weight of the products was carefully performed.     

Synthesis of poly-O-tert-butyl-L-serine and poly-L-serine

The synthesis of polymers containing O-tert-butyl-L -serine, O-tert-butyl-DL -serine, L -serine, and DL -serine is reported. The N-benzyloxycarbonyl-(L or DL )-serine benzyl ester was used to synthesize the corresponding N-benzyloxycarbonyl-O-tert-butyl-(L or DL )-serine benzyl ester. Catalytic hydrogenation of this material gave O-tert-butyl-(L or DL )-serine. The reaction of O-tert-butyl-(L or DL )-serine with phosgene produced the corresponding N-carboxyanhydrides. The kinetics of polymerization of N-carboxyanhydrides were investigated to facilitate, the preparation of block copolymers. The O-tert-butyl blocking group was removed from polymers by treatment with HCl and HBr in benzene. Both high molecular weight (water-insoluble) and low molecular weight (water-soluble) homopolymers have been prepared, as well as water-soluble block copolymers of the type (DL -serine)_x (L -serine)_y, (DL -serine)_z.     

Synthesis of Mono- and Sesquiterpenoids

The synthesis of isocitrate lyase in Candida tropicalis, the growth of which was stimulated by exogenously added biotin, was released from repression by glucose under biotin-deficient conditions. Biotin deficiency reduced remarkably the levels of biotin-enzymes, pyruvate carboxylase and acetyl-Co A carboxylase, in the glucose-utilizing cells of this yeast. A marked increase in intracellular level of pyruvate was observed in the biotin-deficient cells. Acetyl-CoA-donating compounds, such as pyruvate, acetate and alkanes, stimulated the formation of isocitrate lyase in the yeast regardless of the presence or absence of biotin. On the other hand, malate and succinate did not affect the enzyme synthesis. The isocitrate lyase synthesis under biotin-sufficient conditions was repressed by not only glucose but also glucosamine and 2-deoxyglucose. This repression by glucose was not eliminated by cAMP. The stimulated synthesis of isocitrate lyase under biotin-deficient conditions was also observed in C. albicans and C. guilliermondii growing on glucose.     

Synthesis and Properties of Thiodiglycolaldehyde

Thiodiglycolaldehyde (1) has been synthesised by dehydration of its hemialdal form, cis-2,6-dihydroxy-I,4-oxathiane (2a). The hydration and polymerisation of 1 have been studied. The composition and conformational population has been established for solutions of 2a in various solvents. In aqueous solution, 1,2a and its trans isomer 2b, and the acyclic dihydrate and monohydrate were detected. The preferred conformer of 2a has diequatorial OH groups     

A Novel Synthesis of 3-Substituted Furans: Synthesis of Perillen and Dendrolasin

A novel synthetic method of 3-substituted furans was developed and syntheses of perillen and dendrolasin are described.