Succinic acid, first analysis

The most frequently used initiator of this type is 2,2 -azobisisobutyronitrile (AIBN). It was first prepared by Thiele and Hauser [51] who, at the same time, correctly identified its decomposition products. Analysis of the products was refined by Bickel and Waters [53]. According to them, the resulting compounds are the tetramethyldinitrile of succinic acid (84%), isobutyroni-trile (3%) and 2,3,5-tricyanohexane (9%). 

As shown in Table III, the BDSA process offers significant advantages in two primary areas. First, the process has a significantly lower estimated production cost for BDO, succinic acid, and several other commodity chemicals, as well as lower energy consumption during production. Current com production could easily supply the 100 to 200 hundred million pounds of com sugar required for each major chemical plant, and use of this feedstock would decrease petroleum consumption and imports. Further analysis by ACC and New Horizon of the production cost for succinic acid in our fermentation process has included several process modifications to further decrease costs. The estimated costs in 1998 were 0.20/lb sodium succinate. However, the petrochemical routes to BDO have also had further improvements, increased capacity and presumably lowered the target price. 

Composition and Structure. Chemical analysis of the polymer from our first strain (NCIB 11592) indicated that it was a polysaccharide containing the sugars, glucose and galactose, and the carboxylic acids - - succinic and pyruvic - - in the approximate ratios 7 1 1 1. 

By retro synthetic analysis collagenase inhibitor RO0319790 (1) can be assembled from two chiral building blocks, (R) -succinate 2 and (S)-tert-leucine N-methyla-mide 13. As the latter can be prepared from commercially available (S)-tert-leucine 8 our work concentrated in particular on the construction of the first building block 2. In order to assemble the carbon skeleton of 2 in the most efficient way, extremely cheap maleic anhydride 4 was converted in a known ene reaction with isobutylene to provide the cyclic anhydride 6. Hydrogenation of the double bond followed by the addition of EtOH/p-TsOH yielded the racemic diethyl ester substrate 9 for the enzyme reaction. The enzymatic monohydrolysis of 9 afforded the monoacid (R)-2a. (R)-2 a was coupled via its acid chloride with leucine amide 13 to ester 14, which finally was converted into the hydroxamic acid 1. 

Because of the ease of synthesis and industrial importance of diallyl esters much of the research has dealt with the behavior of the isomeric phthalates. Some other dicarboxylic acid esters have been studied by Simpson and Holt [41]. The kinetics of the poljmierization of the diallyl esters of oxalic, malonic, succinic, adipic, and sebacic acid have also been considered. In previous kinetie studies, no differentiation was made between the behavior of the uncyclized monomer (or its free radical) and of the cyclic free-radicals. A priori, differences should have been presumed, but evidently Matsumoto and Oiwa [46] were the first seriously to attempt a kinetic analysis based on the concept that the linear and the cyclic units are two different species. In effect, these two species copolymerize with each other. However, the analysis has not been carried so far as to determine reactivity ratios. 

---