Derivatives of squaric acid, 1,2-dihydroxycyclobutenedione (la), have been prepared and studied. 1,2-Dimethoxycyclobutenedione (lb) was prepared from la. It is readily hydrolyzed to 1 -hydroxy-2-methoxycyclobutenedione (Ic): with water kw = 1.2 X -6 M-1 sec-1; with hydroxide kh = 1.2 X 102 sec-1. Ic is further hydrolyzed to la: with water kf ~2 X ICC7 M_1 sec-1; with hydroxide kf ~2 X KC1 M-1 sec-1. Compound lb was also converted to 1,2-diethoxycyclobutenedione (Id), to l-methoxy-2-aminocyclobutenedione (Ie), and to 1,2-diaminocyclobutenedione (If). In this set alkoxy compounds show ,"" ca. 250 µ, hydroxy compounds max ca. 265 µ, and amino compounds Xmax ca. 270 m,u; hydroxy-alkoxy and amino-alkoxy compounds show double maxima. The hydroxyls are strongly acidic, the alkoxyl compounds behave like reactive esters, and the amino compounds behave like high-melting acidic amides.

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