Precursor compounds

In order to continue the design of a synthesis, 2 is now analysed further by the disconnection strategy for aliphatic bonds. WODCA detects two strategic bonds which are rated 100 and 67, respectively. The disconnection of the bond with the highest rating forms two precursor compounds, 3 and 4 (Figure 10,3-52),... 

Both precursor compounds, 3 and 4, arc available from Fluka, which is checked automatically Iry WODCA searching in this data file. 

The initiator usually constitutes less than 1% of the final product, and since starting the process with such a small amount of material in the reaction vessel may be difficult, it is often reacted with propylene oxide to produce a precursor compound, which may be stored until required [6]. The yield of poloxamer is essentially stoichiometric the lengths of the PO and EO blocks are determined by the amount of epoxide fed into the reactor at each stage. Upon completion of the reaction, the mixture is cooled and the alkaline catalyst neutralized. The neutral salt may then be removed or allowed to remain in the product, in which case it is present at a level of 0.5-1.0%. The catalyst may, alternatively, be removed by adsorption on acidic clays or with ion exchangers [7]. Exact maintenance of temperature, pressure, agitation speed, and other parameters are required if the products are to be reproducible, thus poloxamers from different suppliers may exhibit some difference in properties. 

M - 2 Aromatic isocyanates Aromatic phenols Certain butenols Certain fluorinated amines e.g., C8F17CH2CHICH2NH2 or CF3(CF2)7CH2CH2CH2NH2 Possible Precursor Compounds Polynuclear aromatics (e.g., dihydroxyphenanthrene) Ethylsilanes (dimers to heptamers)... 

M - 3 Possible Precursor Compounds M - 3 ions must be fragments from a higher mass molecular ion (e.g., M—CH3, M—H20). 

M - 14 Possible Precursor Compounds Not observed from a molecular ion however, a mixture of two different compounds may be present. The higher mass ion is M—H. The apparent loss of 14 would be the loss of 15 from the molecular ion. 

Possible Precursor Compounds Carboxylic acids (loss of OH)... 

C6H9, (H0)2P+0 present in phosphate spectra M — 82 Possible Precursor Compounds... 

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