Building block 1,3-propanediol

Biomass is a renewable resource from which various useful chemicals and fuels can be produced. Glycerol, obtained as a co-product of the transesterification of vegetable oils to produce biodiesel, is a potential building block to be processed in biorefineries (1,2). Attention has been recently paid to the conversion of glycerol to chemicals, such as propanediols (3, 4), acrolein (5, 6), or glyceric acid (7, 8). 

Hydroxypropionic Acid (3-HPA). Like the structurally isomeric lactic acid, 3-HPA constitutes a three-carbon building block with the potential of becoming a key intermediate for a variety of high-volume chemicals malonic and acrylic acids, methacrylate, acrylonitrile, 1,3-propanediol, and so forth.Thus, Cargill is developing a low-cost fermentation route by metabolic engineering of the microbial... 

Reactions catalyzed by enzymes or enzyme systems exhibit far greater specificities than more conventional organic reactions. Among these specificities which enzymatic reactions possess, stereospecificity is one of the most excellent. To overcome the disadvantage of a conventional synthetic process, i.e., the troublesome resolution of a racemic mixture, microbial transformation with enzymes possessing stereospecificities has been appHed to the asymmetric synthesis of optically active substances [1-10]. C3- and C4-synthetic units (synthons, building blocks), such as epichlorohydrin (EP), 2,3-dichloro-l-propanol (2,3-DCP), glycidol (GLD), 3-chloro-l,2-propanediol (3-CPD), 4-chloro-... 

Another route to introduce the 1-[ F]fluoroisopropyl residue into the propanol-amine radioligands is represented by the model radiotracers listed in Table 3. [ F]Fluorometoprolol 6 exemplifies the less affine F-labeled counterpart of the )Si-AR-selective radioligand [ C]metoprolol [103]. 1-[ F]Fluoroisopropyl tosylate is the building block of choice used to prepare (+/ )-p F]fluorometopro-lol 6. 1-[ F]Fluoroisopropyl tosylate itself is accessible via the reaction of 1,2-propanediol di(p-toluenesulfonate) with [ F]K(Kryptofix 2.2.2)F. (+/ )-[ F]Fluorometoprolol 6 was proven to possess a similar Pt-AR selectivity like [ C]metoprolol, but its affinity appeared to be too low to potently visualize p-ARs in the heart with PET. 

Hydrogenation of ethyl 2,4-dioxopentanoate with an (S)-MeO-BIPHEP-Ru complex followed by in situ cyclization gives (3R,5S)-3-hydroxy-5-methyltetrahydrofuran-2-one with 98% ee and the 3R,5R isomer with 87% ee in an 84 16 ratio [236]. Ethyl 2-hydroxy-4-oxopentanoate is the only detectable intermediate. 1,3-Diphenyl-l,3-propanediol with a BIPHEMP-Ru complex is transformed to an anti-diol selectively [237]. 1,5-Dichloro-2,4-pentanediol, a versatile chiral building block, is selectively obtained through the BINAP-Ru catalyzed hydrogenation of a... 

Several important examples of metabolic engineering, ranging from applications in basic chemicals, such as the manufacture of propanediol from glucose, to the synthesis of chiral pharmaceutical intermediates, such as (2i )-indanediol, a building block of the HIV protease inhibitor Crixivan (Indinavir , Merck see Chapter 13, Section 13.3.3.30.), are presented in Chapter 20. 

Fig. 15.1 Synthesis generating dansyl-boronic receptors for fructose and building blocks, (i) DMS/Cs2C03 NH4Cl/dioxane, (ii) CH3I/K2C03, (iii) PC13/THF, (iv) 2-methyl-l,3-propanediol-3-amine-phenyl boronate...

Generally speaking, numerous synthons can be extracted from biomass. One known example is that of ethylene, produced from the dehydration of ethanol which is a very common product of fermentation. Another example is 1,3-propanediol, which is a monomer used as a building block for the production of polymers such as polyesters and polyurethanes. Several industrial processes have studied its production by fermentation with the aim of producing it directly from inexpensive plant raw materials (starch or sucrose). To synthesize polyamides and polyesters, we also aim to produce a,(o-dicarboxylic acids by the biological conversion of esters from vegetable oils. 

One of those value-added chemicals could be 1,3 propanediol (PDO), the key building block for DuPont orona, the company s newest polymer platform, used in applications such as plastic, textile apparel, carpeting, and packaging. 

So far, the following building blocks can be produced microbially for polymerization purposes hydroxyalkanoic acids with many structural variations, lactic acid, succinic acid, (i )-3-hydroxypropionic acid, bioethylene produced from dehydration of bioethanol, 1,3-propanediol, and c/ s -3,5-cyclohexadiene-I,2-diols from microbial transformation of benzene and other chemicals. They have been successfully used for making various bacterial plastics. 

In the category of the polymers produced from bio-based monomers, the polyesters used to be more popular. Thus, historically, the main studied monomers were bi-functional molecules, such as lactic acid, an a-hydrmy acid able to self-condense for the production of polylactic acid (PLA) 1.3-propanediol (PDO) leading to Dupont s Sorona after condensation with terephthalic acid and succinic acid, foreseen to be a key bio-based building block and leading to polybutylene succinate (PBS) after condensation with 1,4-butanediol. 

PD is currently produced commercially in small quantities by chemical synthesis using the toxic feedstock acrolein. Although 1,3-PD has not been produced on a large scale, there are dozens of potential uses in polymer synthesis and as a chemical intermediate (26), Cameron has also been involved in studies on strains of Clostridium thermosaccharolyticum that produce R(-)-1,2-propanediol, a useful chiral building block in organic synthesis (27),... 

Desymmetrization of Prochiral and wieso-Diols. Chiral 1,3-propanediol derivatives are useful building blocks for the preparation of enantiomerically pure bioactive compounds such as phospholipids [176], platelet activating factor (PAF), PAF-antagonists [177], and renin inhibitors [178]. A simple access to these syn-thons starts from 2-substituted 1,3-propanediols (Scheme 3.8). Depending on the substituent R in position 2, (/ )- or (5)-monoesters were obtained in excellent optical purities using Pseudomonas sp. lipase (PSL) [179-182]. The last three entries demonstrate an enhancement in selectivity upon lowering the reaction temperature [183]. 

Sorona, a polyester marketed by DuPont Staley Bio Products Co., LLC [11] is a good example of this. 1,3-Propanediol is the key building block for the synthesis of this polyester. Sorona, that is currently on the market is still made from petroleum-derived 1,3-propanediol, but a joint venture consisting of DuPont and Tate Lyle PLC, was formed that is developing the technology for the fermentation of com sugar to yield 1,3-propanediol. Thus, a polymer that is based in part on a renewable resource was developed and it is projected drat by 2006 Sorona production will be converted to agriculturally derived 1,3-propanediol. 

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