Syntheses of biologically active

This method can be adapted for the synthesis of biologically active compounds the 2,2-difluoro derivative of the antibacterial pleuromutalin a tricyclic terpenoid, was prepared in 31% yield from 2-diazopleuromutahn and dilute fluorine in chloroform in the presence of potassium fluoride at 50 °C [96]... 

Hydrazine and its derivatives find considerable use in the synthesis of biologically active materials, dyestuff intermediates and other organic derivatives. Reactions of aldehydes to form hydrazides (RCH=NNH2) and azines (RCH=NN=CHR) are well known in organic chemistry, as is the use of hydrazine and its derivatives in the synthesis of heterocyclic compounds. 

Tietze L. F., Modi A. Multicomponent Domino Reactions for the Synthesis of Biologically Active Natural Products and Drugs Med. Res. Rev. 2000 20 304-322 Keywords Diels-Alder reactions... 

Okamura H., Iwagawa M. and Nakatani M. Development of Base Catalyzed Diels-Alder Reaction of 3-Hydroxy-2-Pyrone and Application to Synthesis of Biologically Active Compounds Org. Chem. Japan 1999 57 84... 

Mikolajezyk M, Balczewski P (2003) Phosphonate Chemistry and Reagents in the Synthesis of Biologically Active and Natural Products. 223 161-214 Mikolajezyk M, see Drabowicz J (2000) 208 143-176... 

Properly substituted phosphonates, which serve as key intermediates for the synthesis of biologically active compounds [39,54], have been prepared via the photo-induced 1,4-addition of phosphites onto Michael ketones (Scheme 19). 

Michalski J, Dahkowski W (2003) State of the Art. Chemical Synthesis of Biophosphates and Their Analogues via PHI Derivatives. 232 93-144 Mikolajczyk M, Balczewski P (2003) Phosphonate Chemistry and Reagents in the Synthesis of Biologically Active and Natural Products. 223 161-214 Mikolajczyk M, see Drahowicz J (2000) 208 143-176 Millar JG (2005) Pheromones of True Bugs. 240 37-84... 

Phosphonate Chemistry and Reagents in the Synthesis of Biologically Active and Natural Products... 

VIII. Synthesis of Biologically Active Carba-oligosaccharides. 74... 

Preparation of 2-fluorofuranoses is also important in relation to the synthesis of biologically active 2 -fluoro derivatives of nucleosides (see Section 111,4). Su and coworkers prepared the 2-triflates 236 and 239 through acid-catalyzed methanolysis of 3,5-di-O-benzyl-1,2-(9-isopropylidene-a-D-ribofuranose [to give 235 (major) and 238] and subsequent triflylation. On treatment with fluoride ion, the anomer 236 afforded exclusively the furan derivative 237, whereas the a anomer 239 gave the 2-fluoro compound 240... 

Abstract A -Heterocyclic carbene complexes produced on industrial scale are presented in this chapter along with a discussion about their production. Details of processes employing NHC complexes on pilot to industrial scales are discussed. These are frequently oriented towards the synthesis of biologically active molecules, however, examples are given for rubber formation and for 1-octene synthesis, a comonomer for polyethylene synthesis. 

His research program focuses on the asymmetric synthesis of biologically active, stereo-chemically complex, natural products. Target molecules are selected which pose unique challenges in asymmetric bond construction. A complex multistep synthesis endeavour... 

Brown T, Holt H Jr, Lee M (2006) Synthesis of Biologically Active Heterocyclic StUbene and Chalcone Analogs of Combretastatin. 2 1-51... 

Intramolecular arylations are possible and several studies have examined the synthesis of biologically active compounds such as oxindoles.181 For example, a synthesis of physovenine has been reported using this methodology. 

Haase C, Seitz O (2007) Chemical Synthesis of Glycopeptides. 267 1-36 Hahn F, Schepers U (2007) Solid Phase Chemistry for the Directed Synthesis of Biologically Active Polyamine Analogs, Derivatives, and Conjugates. 278 135-208 Hansen SG, Skrydstrup T (2006) Modification of Amino Acids, Peptides, and Carbohydrates through Radical Chemistry. 264 135-162... 

This type of substitution reaction is useful forthe synthesis of biologically active nucleosides. 1-Deoxy-l-nitroribose reacts with 2,4-bis(trimethylsilyloxy)pyrimidine in the presence of FeCl3 in MeCN to give the nucleoside in 77% yield (Eq. 7.30).34... 

Desyl ethers are key intermediates in the synthesis of biologically active furanopy-rones. MW-assisted synthesis of these has been performed in an open vessel under PTC solvent-free conditions (Eq. 19) by alkylation of 7-hydroxy-4-methyl coumarin with desyl chloride [30],... 

Kim et al. describe the synthesis of biologically active furanone compounds (Table 1) involving the formation of an amino and a hydroxyl compound... 

Synthesis of biologically active epoxides were reported by Le Blanc et al. and were synthesized initially as a route into the pyrazole compounds shown in Sect. 3.2.1a Scheme 48 [80]. Scheme 35 shows the synthesis of two of the most active epoxides 139a and 139b. They were formed from the reaction of chal-cones (140a and 140b, respectively) by reaction with H2O2 and K2CO3 in MeOH... 

Abstract. This article describes recent achievements of my research group in the Leibniz-Institut fiir Katalyse e.V. in the area of applied homogeneous catalysis for the synthesis of biologically active compounds. Special focus is given on the development of novel and practical palladium and copper catalysts for the functionalization of haloarenes and haloheteroarenes. 

The hydrogenation of ketones with O or N functions in the a- or / -position is accomplished by several rhodium compounds [46 a, b, e, g, i, j, m, 56], Many of these examples have been applied in the synthesis of biologically active chiral products [59]. One of the first examples was the asymmetric synthesis of pantothenic acid, a member of the B complex vitamins and an important constituent of coenzyme A. Ojima et al. first described this synthesis in 1978, the most significant step being the enantioselective reduction of a cyclic a-keto ester, dihydro-4,4-dimethyl-2,3-furandione, to D-(-)-pantoyl lactone. A rhodium complex derived from [RhCl(COD)]2 and the chiral pyrrolidino diphosphine, (2S,4S)-N-tert-butoxy-carbonyl-4-diphenylphosphino-2-diphenylphosphinomethyl-pyrrolidine ((S, S) -... 

The enantioselective hydrogenation of prochirai heteroaromatics is of major relevance for the synthesis of biologically active compounds, some of which are difficult to access via stereoselective organic synthesis [4], This is the case for substituted N-heterocycles such as piperazines, pyridines, indoles, and quinoxa-lines. The hydrogenation of these substrates by supported metal particles generally leads to diastereoselective products [4], while molecular catalysts turn out to be more efficient in enantioselective processes. Rhodium and chiral chelating diphosphines constitute the ingredients of the vast majority of the known molecular catalysts. 

Enantioselective hydrogenation of />-kelo esters catalyzed by the modified Raney Ni is useful for the synthesis of biologically active compounds, as shown in Figure 32.15 [56-58]. A large-scale synthesis of (-)-tetrahydroHpstatin (orlistat), a pancreatic lipase inhibitor (F. Hoffmann-La Roche AG), is carried out using this method [58]. 

Enantioselective hydrogenation of simple ketones catalyzed by BINAP/chiral diamine-Ru complexes is applied to the synthesis of biologically active compounds and a chiral phosphine ligand. Some examples are shown in Figure 32.44 [85 a, 87, 102, 128, 130, 135],... 

Some developments have been carried out for the enantioselective synthesis of biologically active compounds. One such example is the synthesis of ethyl (R)-2-hydroxy-4-phenylbutyrate, an important intermediate for the angiotensinconverting enzyme (ACE) inhibitor benazepril, or for coenzyme A, using the NORPHOS ligand (Scheme 33.9) [21]. 

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