| abstract |
There are described new squaric acid esters, particularly mono-ortho esters, di-ortho esters, ortho ester anhydrides and ortho ester halides of squaric acid; a new process for producing these squaric acid esters; and a process for converting the squaric acid esters into squaric acid. It is possible by the new process to produce, with the use of readily obtainable starting products, the new squaric acid esters according to the invention in an economical manner and with good to very good yields; and the squaric acid esters can be converted under mild reaction conditions into squaric acid. |