1.4- Butanediol synthesis

Synthesis MDI prepolymer with 1000 MW polyfhexamethylene adipate) polyol, NCO/OH = 2.0, chain extended with 1,4-butanediol. 

Note that this method does not work on simple esters. In addition, TMSOCH2CH2OTMS/TMSOTF has been used to effect this conversion.The same process was used to introduce the cyclohexyl version of this ortho ester in a quassinoid synthesis. Its cleavage was effected with DDQ in aqueous acetone.(R,R)-2,3-Butanediol can be used to resolve the lactone. 

Oxidation of n-hutane to maleic anhydride is becoming a major source for this important chemical. Maleic anhydride could also be produced by the catalytic oxidation of n-butenes (Chapter 9) and benzene (Chapter 10). The principal use of maleic anhydride is in the synthesis of unsaturated polyester resins. These resins are used to fabricate glass-fiber reinforced materials. Other uses include fumaric acid, alkyd resins, and pesticides. Maleic acid esters are important plasticizers and lubricants. Maleic anhydride could also be a precursor for 1,4-butanediol (Chapter 9). 

Simple conjugated dienes used in polymer synthesis include 1,3-butadiene, chloroprene (Z-chloro-l -butadiene), and isoprene (2-methyl-l,3-butadiene). Isoprene has been prepared industrially by several methods, including the acid-catalyzed double dehydration of S-methyl-l/S-butanediol. 

The enzymatic synthesis of polyesters from activated diesters was achieved under mild reaction conditions. The polymerization of bis(2,2,2-trichloroethyl) glutarate and 1,4-butanediol proceeded in the presence of PPL at room temperature in diethyl ether to produce the polyesters with molecular weight of 8.2 x 10. Vacuum was applied to shift the equilibrium forward by removal of the activated alcohol formed, leading to the production of high molecular weight polyesters. The polycondensation of bis(2,2,2-trifluoroethyl) sebacate and aliphatic diols took place using lipases BC, CR, MM, and PPL as catalyst in diphenyl ether. Under the... 

The synthesis of both haliclamines A (64) and B (65) has been achieved (Scheme 6). The first synthesis of both 64 and 65 [35,36] was a convergent approach starting from the monoprotection and functional group interconversions (FGls) of 1,4-butanediol (66) to the monoprotected iodide (67), which... 

Synthesis of 2,3-butanediol enantiomers syn-hydroxylation of trans-2-butene. Retrosvnthetic Analysis... 

Significant synthetic applications of the nickel-salen catalysts are the formation of cycloalkanes by reduction of <>, -a-dihaloalkanes255,256 and unsaturated halides,257,258 the conversion of benzal chloride (C6H5CHC12) into a variety of dimeric products 259 the synthesis of 1,4-butanediol from 2-bromo- and 2-iodoethanol260 or the reduction of acylhalides to aldehydes261 and carboxylic acids.262... 

Lithiated chiral oxazolines have been shown to react with various electrophiles, generating a new asymmetric center with considerable bias. This process has led to the synthesis of optically active a-alkylalkanoic acids,47 n-hydroxy(methoxy)alkanoic acids,48 / -hydroxy(methoxy)alkanoic acids,49 n-substituted y-butyrolactones,50 and 2-substituted-l,4-butanediols (Fig. 2-4).50... 

Butanediol dehydration, 41 155 Butane-2,3-dione synthesis, 41 302-303 Butanethiol, dissociation, 37 292 -Butanol, see 1-Butanol 2-Butanol... 

In this procedure, the diol to be used in the synthesis of the polyester is used as the inert diluent in the synthesis step of the bis-carbamate. This avoids the requirement to use a solvent that then has to be removed prior to the polyester synthesis. The 1,4-butanediol is then incorporated into the polyester in the second stage of the reaction. 

The conventional synthesis of aliphatic polyesters based on adipic acid and a range of diols, such as 1,4-butanediol or 1,6-hexanediol, involves a high-temperature esterification reaction typically at 240-260 °C and an organometallic catalyst such as stannous octano-ate. The use of enzyme catalysis results in a much lower reaction temperature, but also the possibility of removing the esterification catalyst, giving the polyester significantly improved hydrolysis resistance. 

Fujita and Yamaguchi et a. reported a new method for the N-heterocyclization of primary amines with diols catalyzed by the l/NaHC03 system, and its application to the asymmetric synthesis of (S)-2-phenylpiperidine [61], The representative results of the reaction of primary amines with diols are summarized in Table 5.11. As shown in entry 1, the reaction of benzylamine with 1,4-butanediol at 110°C for... 

Baryshnikov and co-workers used the same methodology for the synthesis of 5,5 -dinitro-4,4 -bis( 1,2,3-triazole) (133) (DNBT) from l,l,4,4-tetranitro-2,3-butanediol diacetate (132) in the presence of sodium azide. 

The use of tartrate esters was an obvious place to start, especially since both enantiomers are readily available commercially and had already found widespread application in asymmetric synthesis (Figure 11) (e.g.. Sharpless asymmetric epoxidation).23.24 Reagents 36-38 are easily prepared and are reasonably enantioselective in reactions with achiral, unhindered aliphatic aldehydes (82-86% ee) typical results are given in Figure 12.3c,h Aromatic and a,p-unsaturated aldehydes, unfortunately, give lower levels of enantioselection (55-70% e.e.). It is also interesting to note that all other C2 symmetric diols that we have examined (2,3-butanediol, 2,4-pentanediol, 1,2-diisopropylethanediol, hydrobenzoin, and mannitol diacetonide, among others) are relatively ineffective in comparison to the tartrate esters (see Table ll).25... 

Pedamide 536 was converted by treatment with trimethyloxonium tetrafluoro-borate to methyl pedimidate (549) (475), which was connected by the reaction sequence shown in Scheme 69 to (-l-)-acetylpederic acid (550), prepared via a route similar to that to the racemic pederamide (536) from (—)-(2/ ,3/ )-2,3-butanediol. The ratio of the resulting (-l-)-pederin (147) to (+)-10-epipederin (551) was 1 3. This ratio can be inverted to 60 14 by a stereocontrolled synthesis (476) including connection of methyl pedimidate (549) and (+)-selenoacid (552)... 

Epoxy-l-butene (1) is a versatile intermediate for the production of commodity, specialty and fine chemicals (2). An important derivative of 1 is 2,5-dihydrofuran (2,5-DHF). This heterocycle is useful in the production of tetrahydrofuran (3), 2,3-dihydrofuran (4), 1,4-butanediol (5), and many fine chemicals (e.g., 3-formyltetrahydrofuran (6) and cyclopropanes (7)). The homogeneous, Lewis acid and iodide salt-catalyzed rearrangement (isomerization) of 1 to 2,5-DHF has been known since 1976 (8) and is the only practical method for 2,5-DHF synthesis. 

The synthesis of AMO involves treatment of 3,3-bis(chloromethyl) oxetane (BCMO) with sodium azide in the DMF medium at 85 °C for 24 h. Similarly, AMMO which is a monofunctional analog of AMO is synthesized by the azidation of chloro/tosylate product of 3-hydroxymethyl-3-methyl oxetane (HyMMO) with sodium azide in DMF medium at elevated temperatures. These energetic monomers are readily polymerized to liquid curable prepolymers with the help of boron trifluoride etherate/l,4-butanediol initiator system and the outlines of synthesis [147-150] of poly(BAMO) [Structure... 

Periodate regeneration was technically applied for the synthesis of dialdehyde starch from starch (Table 4, No. 64) and recently for the generation of acetaldehyde from 2,3-butanediol (Table 4, No. 65)... 

Diacetoxy-2-butene. Mitsubishi commercialized a new proces, the acetoxy-lation of 1,3-butadiene, as an alternative to the Reppe (acetylene-formaldehyde) process for the production of l,4-diacetoxy-2-butene. l,4-Diacetoxy-2-butene is tranformed to 1,4-butanediol used in polymer manufacture (polyesters, polyurethanes). Additionally, 1,4-butanediol is converted to tetrahydrofuran, which is an important solvent and also used in polymer synthesis. 

Synthesis Fischer-Tropsch synthesis 100-700 ammonia propionic and acetic acid urea (fertilizers) butanediol methanol hydrocarbons... 

---