isat-an element derived from L. isat-is (Gr. ἰσάτις) woad, used in Chem. to form the name of isatin (see below), and of other bodies related to it and to indigo. Among these are:isatic|aɪˈsætɪk|isatic acid, C8H7NO3 (= isatin + H2O), substitution products of which are bromisatic (C8H6BrNO3), chlorisatic, etc., acids; the salts are isatates|ˈaɪsəteɪts|, broˈmisatates, chloˈrisatates, etc. isatimide|aɪˈsætɪmaɪd|, the imide of isatin, C24H17N5O4. isatite: see isatin. iˈsatogen, any compound containing the bicyclic group C8H4NO2 found in isatin; hence isatoˈgenica.ˌisato-sulˈphuricisato-sulphuric acid, an acid containing the elements of isatin and sulphuric acid or sulphuric anhydride; the salts of which are isato-sulphates. ˈisatyde († isathyd), a substance bearing the same relation to isatin that indigo-white bears to indigo-blue, being formed from it by the addition of one atom of hydrogen.1845Penny Cycl. 1st Suppl. 346/1 Isatic acid..is perfectly insoluble in cold water, but when heated in water it is decomposed into isatin and water.1865–72Watts Dict.Chem. III. 404 The solution..deposits..crystals of isatin, which in fact differs from isatic acid, only by the elements of water.Ibid. 405 Chlorisatate of potassium..crystallizes in shining flattened quadrilateral needles of a light yellow colour.Ibid., The other salts of chlorisatic acid are obtained by double decomposition.Ibid. 409 Isatosulphuric acid is a strong acid, separating even the stronger mineral acids from their salts.Ibid. 410 Isatosulphite of Ammonium,..of Potassium.Ibid. 411 Isatyde is white, with a slightly greyish tint, tasteless, and inodorous. It..separates on cooling in microscopic scales.1882Jrnl.Chem.Soc. XLII. 198 Isatogenic acid is very unstable, and cannot be obtained either from the above salt, or from free orthonitropropiolic acid, as it is immediately converted into isatin.Ibid. 620 To ascertain the nature of the isatogen-group, experiments were made on its derivatives.1889Roscoe & Schorlemmer Treat.Chem. III. v. 262 When the solution is poured into water, the isatogenic acid decomposes instantaneously into carbon dioxide and isatin.1916Chem.Abstr. X. 1334 The isatogens are typical quinones, forming a new class of m-quinoid compds., in which the group N:O plays the role of a CO group.1948Wengraf & Baumann tr.Diseren's Chem.Technol. Dyeing & Printing i. i. 26 The formation of indigo can be explained by an intermediate rearrangement of the o-nitrophenyl propiolic acid into isatogenic acid... The latter product is reduced to indigo by splitting off CO2.1965Jrnl. Pharmacy & Pharmacol. XVII. 736 The isatogens..were all effective against Gram-positive organisms.1972W. A. Remers in W. J. Houlihan Chem. Heterocyclic Compounds XXV. i. 193 Isatogens..also undergo addition to the 1,2-double bond. Add: isaˈtogenate, a salt or ester of isatogenic acid.1882Jrnl.Chem.Soc. XLII. 198 (heading) Ethyl isatogenate. This compound is obtained by the action of concentrated sulphuric acid on ethyl orthonitropropiolate; it crystallises in yellow needles, m.p. 115°.1935Chem.Abstr. XXIX. 1089 Me isatogenate is reduced at low temp. by dil. PhNHNH2 to the ketoindolenine.