Propanediol derivatives

Although not of industrial importance, several asymmetric syntheses of (R)-pantolactone (9) have been developed. Stereoselective abstraction of the j Z-proton of the achiral 1,3-propanediol derivative (23) by j -butyUthium-(-)-sparteine, followed by carboxylation and hydrolysis, results in (R)-pantolactone in 80% yield and 95% ee (53). 

Refs l)BeiI - not found 2)H.P. den Otter, Rec 5 7, 13-24 (1938) 3)CA 32, 335 4 (1938) Note Compare the above compds with Anilino-propanediol derivs described in Vol l,p A434-R... 

Zhang S. and Horrocks, A.R. 2003. Substantive intumescence from phosphorylated 1,3-propanediol derivatives substituted on to cellulose. J. Appl. Polym. Sci. 90( 12) 3165—3172. 

Theil, F., Femke, K., Ballschuh, S., Kunath, A., and Schick, H. 1995. Fipase-catalyzed resolution of 3-(aryloxy)-l,2-propanediol derivatives-towards an improved active-site model of Pseudomonas cepacia lipase (Amano PS). Tetrahedron Asymm., 6, 1323-1344. 

Prochiral Compounds. The enantiodifferentiation of prochi-ral compounds by lipase-catalyzed hydrolysis and transesterification reactions is fairly common, with prochiral 1,3-diols most frequently employed as substrates. Recent reports of asymmetric hydrolysis include diesters of 2-substituted 1,3-propanediols and 2-0-protected glycerol derivatives. The asymmetric transesterification of prochiral diols such as 2-0-benzylglycerol and various other 2-substituted 1,3-propanediol derivatives is also fairly common, most frequently with Vinyl Acetate as an irreversible acyl transfer agent. 

Methocarbamol was developed in 1956 in the laboratories of A.H. Robins. Studies were directed towards the development of propanediol derivatives which possessed muscle relaxant properties superior to those of mephenesin, which had low potency and a short duration of action1 >2,3. 

Yokomatsu, T., Minowa. T.. Murano. T.. and Shibuya, S., Enzymatic desymmetrization of prochiral 2-benzyl-l,3-propanediol derivatives. A practical chemoenzymatic synthesis of novel phosphorylated tyrosine analogues. Tetrahedron. 54, 9341, 1998. 

DEPAP, but not aniline or other 3-(A-phenylamino)- 1,2-propanediol derivatives, induced both apoptosis and necrosis in human peripheral blood lymphocytes in vitro in a time- and concentration-dependent fashion. In short-term cell cultures, possibly representative of the toxic oil syndrome acute phase, DNA degradation occurred rapidly. Apoptosis preceded membrane damage. In longer-term cultures, cytotoxicity was characterized by necrosis. As the cells die, abnormal forms of autoantigens are released, activating autoreactive lymphocytes, which could ultimately initiate autoimmune disease (Gallardo et al., 1997 Lahoz et al., 1997). 

Sila propanediol derivatives (15,16), and butanediol, pentanediol, hexanediol and heptanediol derivatives (17,18, 21, 22) (Table 11.1-17) have also been prepared. 

Optically active 2-substituted- 1,3-propanediol derivatives were prepared as shown in equation 45. The bis-trimethylsilylated 1,3-diols were condensed with /-menthone in the presence of trimethylsilyl triflate to give the corresponding diastereomeric ketals, which were separated and subjected to further transformations. For example, the cleavage was carried out via a Mukaiyama reaction to generate the a-alkoxy ketone, which could be protected and then cleaved to the optically active, unsymmetrical, monoprotected 1,3-diol52. 

Methods of synthesis of polymeric plasticizers are discussed in several pat-ents. ° ° "° Endcapped polyalkylene ethers were prepared for use in polyester resins. Different propanediol derivatives are synthesized to form polyester-type plasticizer. In the synthesis of polyester-type plasticizer it is important to avoid presence of unreacted acids. A second stage reaction is conducted in order to remove the odor from the polyester plasticizer." First, the plasticizer is synthesized in the presence of a molar excess of alcohol, then hydroxyl groups are reacted with mono- or difimctional isocyanates." Polyester plasticizer is also produced from a waste stream of non-volatiles recovered as a by-product of oxidation of cyclohexanone. 

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]. 

Figure 30.9 A swimsuit made (in part) from corn—The synthesis of poly(trimethylene terephthalate) from 1,3-propanediol derived from corn...

VeUsek, J., Davidek, J., Davidek, T., Hamburg, A. 3-Chloro-1,2-propanediol derived amino alcohol in protein hydrolysates. J. Food Sci. 56, 136 (1991) Velisek, J., Davidek, J., Kubelka, V, Janisek, G., Svo-bodava, Z., Simicova, Z. New chlorine-containing organic compounds in protein hydrolysates. J. Agric. Food Chem. 28, 1142(1980)... 

General Synthesis.—One of the more significant publications of 1976 is a full report 1 from Meyer s group on the preparation of chiral a-alkylalkanoic acids (2) in up to 80% optical yield, by alkylation of chiral 2-oxazolines (1) (Scheme 1). The thorough study has revealed that alkyl iodides or activated halides afford maximum yields, and that no racemization occurs on hydrolysis thus the propanediol derivative (3) can be recycled. In addition, it is possible to predict which enantiomer of acid (2) will be obtained on double alkylation of oxazoline (4) by due consideration of the order of alkylation. The carbanion from (4) has also been found to be capable of chiral recognition of racemic secondary alkyl iodides to afford 3-alkylalkanoic acids in ca. 40% optical purity. In similar studies, oxazoline... 

Takabe, K, Hashimoto, H., Sugimoto, H., Nomoto, M., and Yoda, H. (2004) First asymmetric synthesis of the marine furanosesterterpene natural product, (18S)-variabilin, employing enzymatic desymme-trization of propanediol derivatives. Tetrahedron Asymmetry, 15, 909-912,... 

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