Preparation of Cyan Dyes from 6-Diethylaminobenzo[b]furan-2-carboxaldehyde

Abstract

6-Diethylaminobenzo[b]furan-2-carboxaldehyde was synthesized in four steps and 48% overall yield starting from 4-diethylaminosalicylaldehyde. Five cyan dyes were made from this aldehyde using malononitrile dimer and 2-dicyanomethylene-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran. The crystal structures of two dyes are included.

Keywords:

• Benzofuran
• dyes
• malononitrile dimer
• polyene

ACKNOWLEDGMENTS

The authors thank several colleagues from Naval Air Warfare Center: Dr. Andrew P. Chafin for molecular modeling of structures related to dyes 3 and 6; Brad Douglas for preparing the piperidinium acetate; Dr. Richard A. Hollins for preparing the TCF acceptor; Dr. Geoffrey A. Lindsay for advice and encouragement throughout the course of this work; Ann M. Moorehead and Linda L. Robinett of the Technical Library for obtaining Refs. 1 and 25; and Dr. Zachary A. Sechrist for assistance with UV/vis spectroscopy.

Notes

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