Methyleneiminodiacetic acid derivatives of some 7-hydroxycoumarins as analytical reagents

✍ Scribed by M.A.Salam Khan; W.I. Stephen

• Publisher: Elsevier Science
• Year: 1970
• Tongue: English
• Weight: 610 KB
• Volume: 49
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/s0003-2670(00)86785-9

✦ Synopsis

EXPERIMENTAL

Prefiavation of reagents

7-Hydroxycoumarin

and its various derivatives (see Table ) were generally prepared by the PECHMANN reaction 5; the g-carboxylic acid ethyl ester derivative was prepared by the method of KNOEVENAGEL 0. In some cases the modifications suggested by SESHADRI et al.798 were introduced in order to improve yields. For the preparation of 3-acetoxy-7-hydroxycoumarin the method of BALAIAH et ~1.0 was found the most satisfactory. Full details of the preparations of these derivatives are described elsewherelo. In general, few difficulties were encountered in obtaining the pure coumarin derivatives, which were characterised by melting points, elemental analyses and thinlayer chromatopraphy.

The methyleneiminodiacetic acid derivatives of the hydroxycoumarins were prepared by Mannich-type condensation of the relevant coumarin with iminodiacetic 'acid and formaldehyde. In order to establish the optimal conditions for the condensation, since few details of such condensations have been pubhshed in the literature, the A~aal.Chim.