Synthetic pyridine

Synthetic polymers Synthetic Processes Synthetic pyridine Synthetic rubber... 

Figure 3 shows the production of acetaldehyde in the years 1969 through 1987 as well as an estimate of 1989—1995 production. The year 1969 was a peak year for acetaldehyde with a reported production of 748,000 t. Acetaldehyde production is linked with the demand for acetic acid, acetic anhydride, cellulose acetate, vinyl acetate resins, acetate esters, pentaerythritol, synthetic pyridine derivatives, terephthaHc acid, and peracetic acid. In 1976 acetic acid production represented 60% of the acetaldehyde demand. That demand has diminished as a result of the rising cost of ethylene as feedstock and methanol carbonylation as the preferred route to acetic acid (qv). 

The nameplate capacities for acetaldehyde production for the United States in 1989 are shown in Table 5 (120). Synthetic pyridine derivatives, peracetic acid, acetate esters by the Tischenko route, and pentaerythritol account for 40% of acetaldehyde demand. This sector may show strong growth in some products but all of these materials maybe prepared from alternative processes. 

Pjridine Bases. Formerly, pyridine bases were recovered from coal-tar light oils (18), but in more recent years synthetic pyridine and methylpyridine have mostiy replaced the coal-tar products. 

Synthetic products, sulfur use in, 23 591 Synthetic pulps, 16 96 Synthetic pyridines, 21 116, 118 Synthetic receptors, 3 808-810 Synthetic research... 

Safety Aspects in Handling and Exposure. Pyridine compounds are ubiquitous in the natural environment, and are often found in foods as minor flavor and fragrance components. Some synthetic pyridines are used as food additives. A high proportion of pyridine compounds shows some type of bioactivity, albeit mostly minor, such as herbiddal, insecticidal, or medicinal activity. Therefore, all the normal precautions should be exercised when handling pyridines that would be used when handling other organic products that are potentially bioactive. 

In 1995, the world capacity of synthetic pyridines was about 94,000 tonnes per year. 

Y-27632 (25) is a synthetic pyridine derivative that inhibits Rho kinase (ROCK)-I and ROCK-II. As expected, Y27632 (25) inhibits the formation of stress fibers in cultured cells and motility in a number of systems [36]. In addition, two isoquinoline sulfonamides, HA1077 (26) and H-1152 (27), were developed as ROCK inhibitors [37,38]. 

Pyridine bases namely 2 4-picolines are important commodity chemicals which are used in pharmaceuticals, rubber eind agricultural industries. 2-picoline is consumed for several different pesticides, and is used in the production of 2-vinylpyridine, which is a component of styrene-butadiene-vinylpyridine terpolymer latexes. The major outlet for 4-picoline is for the manufacture of 4-vinylpyridine and INH an anti-tubercular drug. The stringent specifications laid down for these products in pharmaceutical and agricultural applications can not be met from natural sources namely from coal carbonisation byproducts. Synthetic pyridine is the only answer to this problem. 

Acetaldehyde is used in producing acetic acid, acetic anhydride, cellulose acetate, synthetic pyridine derivatives, pentaerythritol, tereph-thalic acid, and many other raw materials. Release of acetaldehyde from poly ethylene terephthalate (PET) bottles into carbonated mineral waters has been observed (Lorusso et al. 1985) 180 ppm was detected in samples kept for 6 months at 40°C (104°F). 

The synthetic pyridine derivative, -(4-(2-carboxy-l-propenyl)benzyl) pyridine hydrochloride (OKY-1555) inhibited thromboxane formation selectively and had an IC50 of 3 nM [135]. Also the corresponding sodium salt (OKY-1581) was a potent and selective inhibitor of thromboxane synthetase [137,138]. 

Many synthetic pyridine derivatives are important as therapeutic agents, for example Isoniazide is a major antituberculosis agent, Sulphapyridine is one of the sulfonamide antibacterials, Prialdoxime is an antidote for poisoning by organophosphates, and Lacidipine is one of several antihypertensive 1,4-dihy-dropyridines. Some herbicides (Paraquat) and fungicides (Davicil) are also pyridine derivatives. 

Nenz, A., Pieroni, M. Commercial Synthetic Pyridine Bases Hydrocarb. Proc., 47, Nr. 11,139 (1968)... 

---