Cresol derivatives

Fragment ions Benzyl alcohol-TMS can be distinguished from a cresol-TMS because benzyl alcohol has its base peak at ml-91. The o-, m-, and p-cresol derivatives can be distinguished from each other and from benzyl alcohol by the relative intensities of the m/z 91 ion. 

Hepatic Effects. Necropsy revealed extensive centrilobular to mid- zonal liver necrosis in a l-year-old baby who had 20 ml of a cresol derivative spilled on his head (Green 1975). 

Renal Effects. A l-year-old baby who died after a cresol derivative was spilled on his head had congested and swollen kidneys that were damaged by tubular necrosis (Green 1975). A man who fell into a vat containing a cresylic acid derivative developed anuria after 36 hours and experienced a steady increase in blood urea levels for 10 days until he died (Cason 1959). Anuria was also seen in a man who apparently absorbed cresol through the skin while working with an antiseptic solution containing concentrated mixed cresols (Larcan et al. 1974). 

Unlike the corresponding rc-cresol derivatives, these dichlorides are not readily transformed into triarylated tellurium chlorides by prolonged boiling with 95 per cent, alcohol or with aqueous sodium carbonate. 

Induction periods. An induction period typically occurs if a free-radical trap is present at a concentration much lower than that of the initiating substance (reactant or added initiator). An often cited example is the temporary inhibition of oxidation of cumene by a cresol derivative [57,84] ... 

Similarly, 2,6-xylenol along with m-cresol has been used for manufactime of 2,3,6-trimethyl phenol, a precursor for di-alpha-tocopherol, popularly known as vitamin-E. On chlorination 3,5-xylenol is converted to 4-chloro-3,5-xylenol — an antifungal medication and some pesticides [1,6]. In sum, some quantities of individual xylenols are used in organic chemical S3mthesis. However compared to cresols derivatives, downstream derivatives of xylenol isomers are relatively stiU not very significant. 

In case of m-cresol derivatives, an official process literature has reported that m-cresol is a possible intermediate for production of antiarrythmic toliprotol which is reportedly produced by Bochringer Ingelheim KG Germany [14]. 

Vitamin E being the fastest growing vitamin, 2,3,6-TMP constitutes the fastest growing m-cresol derivative. One critical factor for fast growth will, however, depend on availability of m-cresol. Currently, m-cresol is available mostly in Japan, USA, and W. Europe mostly as a co-product during manufacture of BHT from meta-para-cresols. Can also be obtained by methylation of 2,6-xylenol on y-aluminium oxide at about 355°C using a 2,6 xylenohmethanol ratio of 2 1. 

DNOC as a basic o-cresol derivative has been discussed in an earlier chapter. Some aspects of this multipurpose agrochemical, an insecticide, an acaricide, a herbicide and also a fungicide, are discussed here in some detail. 

Phenol and cresol derivatives, particularly p-cresol derivatives, have provided important building blocks for the pharmaceutical industry. There are a number of pharmaceutical compounds derived from p-cresol derivatives dilitiazem hydrochloride, the largest one. Trimethoprim, Nadifloxacin, and sulmetozin are other prominent examples. 

Para-anisic aldehyde and p-anisic alcohol are two important p-cresol derivatives which have provided critical feedstocks for some of the important bulk drugs. Trimethoprim made from 3,4,5-trimethoxybenzaldehyde is another example. p-Cresol has already replaced gallic acid as the preferred starting material for 3,4,5-trimethoxy benzaldehyde. As more R D work is undertaken, there will no doubt emerge more finished pharmaceutical items not only from p-cresol but also from o-cresol and m-cresol. Growth of meZo-cresol has indeed been remarkable after the process was commercialized for... 

Flavors, Fragrances, and Food Additives from Cresol Derivatives... 

Use of SCFE for industrial chemicals separation and extraction will ensure a clean process and eco-friendly system. Use of SCFE for separation of m-cresol from a mixture of meta-para-cresols, mixture of xylenols, and cresol derivatives will no doubt open up new possibilities. It is heartening that a few companies are already working on this line, as is evident from proceedings of various international seminars and conferences during the last few years. Some of the high-value pharmaceutical produces are also being seriously persued. 

Many of the constituents of flavors and fragrances are based on p-cresol, m-cresol, o-cresol derivatives or their precursors, such as cymenes. This will be discussed shortly. 

Easy availability of pure p-cresol, o-cresol, and m-cresol particularly in the developed countries of USA, UK, Germany, France, Switzerland, Japan, and even in China and India led to development and commercialization of a large number of cresol derivatives. These have been discussed in details vide Chapters 5-7. 

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