Imino group

Nucleophilic reactivity of the sulfur atom has received most attention. When neutral or very acidic medium is used, the nucleophilic reactivity occurs through the exocyclic sulfur atom. Kinetic studies (110) measure this nucleophilicity- towards methyl iodide for various 3-methyl-A-4-thiazoline-2-thiones. Rate constants are 200 times greater for these compounds than for the isomeric 2-(methylthio)thiazole. Thus 3-(2-pyridyl)-A-4-thiazoline-2-thione reacts at sulfur with methyl iodide (111). Methyl substitution on the ring doubles the rate constant. This high reactivity at sulfur means that, even when an amino (112, 113) or imino group (114) occupies the 5-position of the ring, alkylation takes place on sulfiu. For the same reason, 2-acetonyi derivatives are sometimes observed as by-products in the heterocyclization reaction of dithiocarba-mates with a-haloketones (115, 116). 

Isoxazolines with alkyl substituents are also all liquids (or low melting solids) and incorporation of aryl substituents results in crystallinity. Introduction of carboxy substituents and endocyclic carbonyl or imino groups also has the anticipated effect, with crystalline products being isolated. These trends are illustrated by the data compiled in Table 2. 

BMI was also used as a crosslinking agent for poly(iminoethylene). The Michael addition takes place with the nucleophilic nitrogen of the imino group and the double bonds of the electrophilic BMI. The Michael addition of BMI is now adopted as a crosslinking reaction for polymers with amino end groups [2]. 

The hydrogen of the imino-group may be replaced lay acid and alkyl radicals. In the latter case the sodium compound is tieated with an alkyl iodide. 

In summary, the results for the case of the polymer indicate that only the amino-nitrogens interacts with the ITO surface while the model studies demonstrates that both amino- and imino-groups reacts with ITO. Thus, further investigations arc necessary in order to obtain a complete picture. Studies using model systems that contain the whole cmeraldine base sequence have been initiated [114],... 

The basicity of the nitrogen atom can be influenced by whether the imino group is attached directly to a benzene nucleus or whether a methylene group is interposed. 

Formation of C — C Bonds by Addition to Imino Groups (C = N) 1.4.1. Addition of o-Type Organometallic Compounds to Imino Groups... 

D.1.4. Formation of C —C Bonds by Addition to Imino Groups Houben-Weyl... 

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